bluuebunny/crossref_metadata_2025 huggingface dataset:
Double bond position affects metabolism ofcis‐octadecenoates
Authors: Mounts T. L.
Published: December 2006

The metabolic fate ofcis‐positional isomers of octadecenoates has been compared to that of naturally occurring oleic acid (cis‐Δ9). Radioactive mixtures of tritium‐labeled positional octadecenoate isomer and oleic acid‐10‐14C were administered to laying hens, and their eggs were analyzed for the isotopic ratios (3H/14C) incorporated into total egg lipid, triglycerides, and phospholipids. Variations in the isotopic ratios indicated the comparative metabolic utilization ofcis‐positional isomers Δ8 through Δ12. Incorporation into egg lipid fractions is as follows: triglycerides: Δ9>Δ8, Δ9>Δ10, Δ9>Δ11, Δ9>12; phospholipid: Δ9>Δ8, Δ9>Δ10, Δ9<Δ11, Δ9<Δ12.
Effects of protected cyclopropene fatty acids on the composition of ruminant milk fat
Authors: Cook L. J. , Scott T. W. , Mills S. C. , Fogerty A. C. , Johnson A. R.
Published: December 2006

Unsaturated fatty acids can be protected from ruminal hydrogenation, and, when fed to lactating ruminants, the constituent acids are incorporated into milk triacylglycerols. By this means, it has been possible to reduce the melting point of milk triglycerides and to make softer butter fat. This report shows that, by feeding small amounts of protected cyclopropene fatty acids, one is also able to make harder butter fat.Sterculia foetida seed oil, a rich source of cyclopropene fatty acids, was emulsified with casein and spray dried to yield a free flowing dry powder. When this material was treated with formaldehyde and fed to lactating goats (ca. 1 g cyclopropene fatty acids per day), there were substantial increases in the proportions of stearic acid and decreases in the proportions of oleic acid in milk fat. Similar results were obtained when the formaldehyde‐treated supplements were fed to lactating cows (ca. 3 g cyclopropene fatty acids per day). The effect was considerably less apparent when theS. foetida seed oilcasein supplement was not treated with formaldehyde, suggesting that cyclopropene fatty acids are hydrogenated in the rumen as are other unsaturated fatty acids. The effect of feeding protected cyclopropene fatty acids on the stearic: oleic ratio in milk fat is probably due to cyclopropene‐mediated inhibition of the mammary desaturase enzymes.
Utilization of l‐serine in the in vivo biosynthesis of glycerophospholipids by rat liver
Authors: Yeung K. K. F. , Kuksis A.
Published: December 2006

The incorporation of L‐serine‐U‐14C, L‐serine‐3‐14C, and D,L‐serine‐1‐14C into the glycerophospholipids of rat liver in vivo was determined over a period of 3 min to 13 hr following intravenous injection. The radioactivity from these serines was transferred to variable extent into the glycerol, fatty acid, and nitrogenous base parts of all the glycerophospholipids and neutral lipids. The half‐lives and turnover rates of phosphatidylserine calculated from the precursor‐product specific activity curves obtained with L‐serine‐U‐14C were 14 min and 0.28 μmol/min/liver, respectively. The half‐lives and turnover rates of phosphatidylserine as measured from the decay data of lipid serine from all markers averaged, respectively, 8.2 hr and 0.008 μmol/min/liver. The discrepancy between these turnover rates was attributed to an underestimation of degradation of phosphatidylserine due to its continued biosynthesis and/or an extensive reutilization of L‐serine. By monitoring the formation of radioactive lipid ethanolamine, it was found that phosphatidylserine was decarboxylated at one‐half the rate of lipid serine biosynthesis. It is suggested that as much as one‐half of total phosphatidylserine may be degraded by other mechanisms, such as base exchange with choline, ethanolamine, and serine, as already demonstrated in vitro by other workers. The time course and nature of labeling of phosphatidylcholine was consistent with an extensive conversion of radioactive L‐serine to 1‐carbon fragments and a rapid methylation of phosphatidylethanolamine to phosphatidylcholine.
Quantitation of phosphatidyl N‐methyl‐ and N,N‐Dimethylaminoethanol in rat liver
Authors: Katyal S. L. , Lombard B.
Published: December 2006

The contents of phosphatidyl N‐methyl‐and N,N‐dimethylaminoethanol were determined in the liver of rats injected with (Me‐C14) methionine. Total phospholipids were extracted from aliquots of the liver and fractionated by two‐dimensional thin layer chromatography after addition of carrier phosphatidyl‐N‐methyl‐and N,N‐dimethylaminoethanol. The radioactivity present in the two phosphatide spots was determined and used to calculated total disintegrations per min/100 g body wt. The remainder of the livers was pooled, and total phospholipids were isolated and subjected to acid hydrolysis. N‐methyl‐ and N,N‐dimethylaminoethanol were purified by thin layer chromatography, and their specific activity was determined after quantitation by gas liquid chromatography and radioactivity measurement. The liver contents of phosphatidyl N‐methyl‐ and N,N‐dimethylaminoethanol were determined by dividing disintegrations per min/100 g body wt by the specific activity of N‐methyl‐ or N,N‐dimethylaminoethanol.
Effects of sex on formation and properties of plasma very low density lipoprotein in vivo
Authors: Soler‐Argilaga Carlos , Danon Abraham , Wilcox Henry G. , Heimberg Murray
Published: December 2006

The concentration and composition of the very low density lipoprotein (VLDL) lipids and the behavior of the VLDL in a density gradient in the zonal ultracentrifuge were examined in plasma obtained from normal fed male and female rats before and after intravenous injection of Triton WR‐1339. Concentration of lipids in plasma VLDL of female rats was about half that of male animals. Following injection with Triton WR‐1339, the concentration of VLDL lipids was higher in female rats (triacylglycerol) or similar (phospholipid, cholesterol, and cholesteryl esters) in both sexes. Female rats secreted much more VLDL triacylglycerol into the plasma compartment than did the male animals under the same experimental conditions. No differences were observed in lipid composition of the VLDL or in the position of the VLDL in the zonal rotor after ultracentrifugation in a density gradient of the lipoprotein from plasma of normal male and female rats before treatment with the detergent. However, after treatment with Triton, a higher proportion of the VLDL particles isolated from plasma of female rats displayed a more rapid rate‐zonal flotation in the ultracentrifuge than did the VLDL produced by the male. The VLDL secreted by female rats contained fewer moles of phospholipid and free sterol per mol triacylglycerol than did the VLDL secreted by male animals under identical experimental conditions. The molar ratio of free cholesterol: cholesteryl ester in the VLDL secreted after treatment with Triton increased in both male and female rats. Simultaneously, the content of arachidonic acid in phospholipid of VLDL increased with a concomitant decrease in cholesteryl ester. These changes in fatty acid composition suggest that the inhibitory effect of Triton on lecithin‐cholesterol acyl transferase activity affects the exchange of lipids between VLDL and high density lipoprotein. It can be concluded from the data reported here that sex influences the concentration of plasma lipids in vivo and the output and properties of the VLDL.
Protective effect of 3‐hydroxy‐3‐methylglutaric acid in alcohol‐induced lipemia
Authors: Yousufzai S. Y. K. , Siddiqi Majid , Abdullah A. K.
Published: December 2006

Oral administration of 1 g of 3‐hydroxy‐3‐methylglutaric acid (HMG) before the ingestion of whiskey and a fatty meal markedly reduced the elevation of serum triglycerides, β‐lipoproteins, phospholipids, and cholesterol in man. In rats receiving an ethanol and corn oil mixture, HMG also inhibited the increase in postprandial serum and liver lipids. A comparative study of HMG and nicotinic acid in rats showed that, therapeutically, 50 mg MHG/kg body weight is equivalent to 200 mg nicotinic acid/kg body weight in offering almost total protection against lipemic effects of ethanol.
Effect of dietary cyclopropene fatty acids on the octadecenoates of individual lipid classes of rat liver and hepatoma
Authors: Wood Randall , Chumbler Fred , Wiegand Rex D.
Published: December 2006

The effect of dietary cyclopropene fatty acids on the concentration of octadecenoate chain positional isomers in individual lipid classes of normal liver, host liver, and hepatoma 7288CTC has been determined. The data revealed the following: (a) Saturated and monoene fatty acid percentages of liver phosphatidylcholines and phosphatidylethanolamines werenot affected, but the percentage of saturated fatty acids of the triglycerides and cholesteryl esters was increased while the monoene percentages decreased. (b) Oleate to vaccenate percentage ratios, previously shown to be characteristic of individual lipid classes, were completely disrupted. (c) Oleate concentrations of the two major liver phospholipids were elevated, and vaccenate levels were dramatically reduced. (d) Cyclopropene fatty acids appear to inhibit monoene elongation. (e) The elevated concentrations of oleate indicate that an alternate route of oleate biosynthesis must exist if the Δ9 desaturation is inhibited by cyclopropene fatty acids as reported previously. (f) In contrast to liver, oleate and vaccenate concentrations in hepatoma were not affected by the dietary cyclopropene fatty acids.
Studies on the hydrogen belts of membranes: III. Glycerol permeability of dihydrosphingomyelin‐cholesterol membranes
Authors: Tirri Lawrence J. , Ayengar Narayan K. N. , Lipton Linda C. , Chatterjie Nithiananda , Brockerhoff Hans
Published: December 2006

The permeability of an N‐oleoyldihydrosphingomyelin bilayer against glycerol was similar to that of a bilayer of phosphatidylcholine with identical effective hydrophobic chain length. Cholesterol at 1∶1 molar ratio reduced the permeability, and also reduced the energy of activation of glycerol penetration, an effect not found for diesterphosphatidylcholine with cholesterol. The higher level of the ground state of the entropy of activation for permeability can be interpreted in terms of a hydrogen belt model which postulates lipid‐lipid hydrogen bonding in membranes and explains the effect found as a disturbance of the hydrogen belt structure. Dihydrosphingomyelin can be considered to function as an “extender” in the hydrogen belt network.
Chemical composition of the preen gland secretions from some ciconiiform birds
Authors: Jacob Jürgen
Published: December 2006

The preen waxes from four Ciconiiformes species are shown to be ester waxes of very different composition. Three species possess monoester waxes with branched wax acids and alcohols. In one of these waxes, homologous series of ethyl‐substituted constituents are observed. In contrast to this, the uropygial gland secretion of the marabou is a triglyceride mixture.
Changes in fatty acid composition of cardiac mitochondrial phospholipids in rats fed rapeseed oil
Authors: Dewailly P. , Nouvelot A. , Sezille G. , Fruchart J. C. , Jaillard J.
Published: December 2006

Male Wistar rats were fed rapeseed oil containing high or low levels or erucic acid for 20 weeks, and changes in the fatty acid composition of cardiac mitochondrial phospholipids were studied. Treatment with rapeseed oil containing 46.2% erucic acid showed incorporation of 22∶1 (5.6%) into isolated cardiolipin from heart mitochondria. After high or low (3.7%) erucic rapeseed oil feeding, linoleic acid was slightly incorporated into cardiolipin. Moreover, both of these rapeseed oils induced a significant increase of linoleate‐arachidonate ratio in phosphatidylethanolamine and phosphatidylcholine. This ratio was also significantly increased in fatty acids esterified to the β‐position of these phospholipids. On the basis of such results, we have to consider the role of linolenic acid which is present at a high level in the different rapeseed oils used, as a possible inhibitor of heart microsomal enzymes involved in linoleate arachidonate conversion. Such alterations might account for mitochondrial fragility and myocardial lesions obtained in long term rapeseed oil feeding experiments.
Lipid peroxidation: A mechanism involved in acute ethanol toxicity as demonstrated by in vivo pentane production in the rat
Authors: Litov Richard E. , Irving Dennis H. , Downey Jeanne E. , Tappel Al L.
Published: December 2006

The effect of a single dose of ethanol on lipid peroxidation in three groups of rats fed different amounts of vitamin E was determined by the measurement of pentane in the breath. All rats had increased pentane production above basal levels by 15 min following oral administration of 6 g ethanol/kg body wt. The increase in total pentane production during a 13‐hr test period after intragastric administration of ethanol was greater in the rats fed the vitamin E‐deficient diet than in the rats, fed vitamin E‐supplemented diets (α=2P=0.02). The results support the hypothesis that acute ethanol toxicity involves lipid peroxidation and further demonstrate the usefulness in toxicological studies of monitoring pentane as an index of lipid peroxidation in vivo.
The influence of urea on lipogenesis in renal papillae of rats
Authors: Bojesen Inge N.
Published: December 2006

The osmolality has been determined for the papillary interstitial fluids obtained from the isolated papillae of rats in different states of water balance. Hypertonic buffers for in vitro experiments were prepared by addition of urea to regular Krebs‐Ringer phosphate buffers (340 mosmol/kg H2O) since urea is the most changeable solute of the renal papillary tissue in response to external influences. The effect of such hypertonic buffers on papillary lipogenesis was very pronounced. The fatty acid synthesis from acetate decreased by a factor of 7–9 in response to increased osmolality from 340 to 1370 mosmol/kg H2O. In the physiological range of osmolalities (500–1800 mosmol/kg H2O), the de novo synthesis of papillary glycerolipids from glucose decreased by a factor of ca. 5. A possible specific inhibitory effect of hypertonic buffers on the pentose phosphate cycle was studied with a negative result. It is concluded that the addition of urea causes a decrease of total energy metabolism in the tissue.
Cigarette smoke affects lipolytic activity in isolated rat lungs
Authors: Hartiala Jaakko , Viikari Jorma , Hietanen Eino , Toivonen hannu , Uotila Pekka
Published: December 2006

Isolated perfused rat lungs liberated fatty acids at a rate of 15 μmol/hr during perfusion of triglyceride‐rich medium through the pulmonary vascular bed. About 80% of this activity seemed to result from lipoprotein lipase and 20% to hormone‐sensitive lipase. Ventilation of the lungs with cigarette smoke instead of air during the perfusion reduced fatty acid liberation by 23%. Pre‐exposure of rats to cigarette smoke for either 1 or 10 days did not cause significant changes in lung lipolytic activity compared to sham‐exposed controls.
Comparative studies on the fatty acid composition of moderately and extremely thermophilic bacteria
Authors: Oshima Mieko , Miyagawa Akihisa
Published: December 2006

The fatty acids of three strains of extremely thermophilic bacteria and three strains of moderately thermophilic bacteria were examined by gas liquid chromatography. All the thermophiles contained straight, iso, and ante‐iso branched fatty acids. Iso C17∶0 acid was abundant in both the moderately thermophilic strains (10–33%) and the extremely thermophilic strains (50–61%). The pair of fatty acids iso C15∶0 and iso C17∶0 was the predominant pair in both the moderately (34–64%) and extremely (76–87%) thermophilic strains. The pair of fatty acids ante‐iso C15∶0 and ante‐iso C17∶0 was present in larger amount in moderately (25–34%) than in extremely (8.5–15%) thermophilic strains. No hydroxy cyclopropane, or unsaturated fatty acids were found. One extreme thermophile,Flavobacterium thermophilum HB‐8 was grown at 6 different culture temperatures from 49–82 C, and the changes of its fatty acid composition were studied. The ratios of iso C17∶0/iso C15∶0 and ante‐iso C17∶0/ante‐iso C15∶0 were much greater at higher culture temperatures, indicating chain elongation.
Influence of the polar group on interactions between phospholipids and sterols in monolayers. Rapid decomposition of phosphatidylethanolamines and cholesterol in monolayers at pH 11.9
Authors: Ghosh D. , Lyman R. L. , Tinoco J.
Published: December 2006

Pressure‐area curves were obtained for monolayers of pure lipids or mixtures of lipids in order to investigate the effect of different polar groups upon interactions between molecules of various structures. Cholest‐4‐ene‐3‐one and cholestan‐3‐one were measured alone and in mixtures with di 16∶0‐lecithin, and 16∶0–18∶1‐lecithin, 16∶0–18∶3‐lecithin, and 16∶0–20∶4‐lecithin. All lecithin films were somewhat condensed by the ketones, but much less so than by cholesterol. Cholesterol was measured alone and with either di 16∶0 phosphatidylethanolamine (PE) or rat liver phosphatidylethanolamine at pH 2.0, 5.4 and 11.9. Cholesterol condensed the natural PE at pH 2.0 and 5.4, but not the di 16∶0 PE. At pH 11.9, both cholesterol and PE were chemically unstable in monolayers. The strong interaction of cholesterol with mixed phosphatidylethanolamines in monolayers suggests that cholesterol may also interact strongly with PE in membranes, of which PE are important components.
Fatty acid composition of symbiotic zooxanthellae in relation to their hosts
Authors: Bishop David G. , Kenrick Janette R.
Published: December 2006

Gymnodinoid dinoflagellate symbionts, commonly referred to as zooxanthellae, are widely distributed among marine invertebrates. It has been assumed that they represent only one species,Gymnodinium microadriaticum. The fatty acid composition of total lipids and galactolipids of zooxanthellae isolated from 8 species of corals, 3 species of clams and a foraminiferan have been analyzed and found to vary according to the host. For example, the content of eicosapentaenoic acid in clam zooxanthellae monogalactosyldiacylglycerol was less than 2%, whereas in the same lipid from coral zooxanthellae, the content ranged from 9 to 22%. Corresponding values for the acid in digalactosyl‐diacylglycerol were 1–8% from clam zooxanthellae and 23–40% from coral zooxanthellae. Coral zooxanthellae monogalactosyldiacylglycerol contain higher levels of octadecatetraenoic acid than are found in digalactosyldiacylglycerol, whereas the reverse is true in clam zooxanthellae. The fatty acid composition of the lipids of an axenic culture of zooxanthellae isolated from the clamTridacna maxima are similar to those of cells freshly isolated from the host. The results suggest either that the host is capable of affecting the fatty acid metabolism of the symbiont or that different strains of zooxanthellae occur in corals and clams.
Bile acids: LXI. Synthesis and properties of conjugates of 5α‐bile acids
Authors: Shaw Roger , Elliott William H.
Published: December 2006

Allo bile acids and their taurine‐ and glycine‐conjugates were synthesized by modification of existing procedures. Their chromatographic and spectral properties were investigated and compared with the 5β‐analogs. Some of the naturally occurring 5α‐ and 5β‐conjugates were separable by high performance liquid chromatography via straight‐phase (Corasil II column) or reverse‐phase systems (μBondapak/C18 column), though unsuccessful with thin layer or gas liquid chromatography. Differences between the C‐5 epimers in the infrared and proton magnetic resonance spectra could be attributed to the configurations at the A/B ring junction and the configuration of the 3‐hydroxyl group. The calcium salts of the allo compounds were generally less soluble in water than the 5β‐isomers.
Occurrence of unusual hexadecenoate fatty acids in hepatoma lipids
Authors: Wood Randall , Lee Theresa
Published: December 2006

Cis‐hexadecenoates isolated from rat liver and hepatoma 7288CTC lipids were analyzed for positional isomers by ozonolysis and capillary gas liquid chromatography. In addition to the Δ6, Δ7, Δ9 and Δ11 isomers found in both tissues, the hepatoma neutral and polar lipids contained relatively high percentages of Δ12 and Δ14 hexadecenoates that were virtually absent from liver. The occurrence of these unusual fatty acids may result from an error in lipid metabolism in the hepatoma.
Temperature‐dependent deacylation of molecular species of phosphatidylcholine by microsomal phospholipase A2 of thermally acclimated rainbow trout,Salmo gairdneri1
Authors: Neas N. P. , Hazel J. R.
Published: December 2006

Using the ratios of kinetic parameters, V/Km, the deacylation of different molecular species of 1‐palmitoyl,2‐acyl phosphatidylcholine via microsomal phospholipase A2 (PLA2) was studied in liver tissue of thermally acclimated rainbow trout (Salmo gairdneri). In general, PLA2 from fish acclimated to cold temperatures showed an order of preference for the acyl moieties of 18∶1>18∶1>18∶2>18∶0. Trout acclimated to warm temperatures generally preferred 18∶0 PC, but the actual order of preference depended on the temperature of the assays and the presence of endogenous lipids in the enzyme preparation. At 5 C, the particulate (microsomal) enzyme preferred 18∶0>18∶2>18∶1, but a lipid‐free preparation of the enzyme preferred 18∶2>18∶0>18∶1. At 20 C, particulate enzyme preferred 18∶1>18∶0>18∶2 but purified enzyme preferred 18∶0>18∶2>18∶1. Thus, assay temperature and the presence of microsomal lipids had a greater effect on PLA2 from fish acclimated to warm temperatures than fish acclimated to cold temperatures. The substrate preference of PLA2 is discussed with reference to the previously observed changes in membrane fatty acid composition that occur with thermal acclimation in rainbow trout.
Double‐bond patterns of fatty acids and alcohols in steer and human meibomian gland lipids
Authors: Nicolaides N. , Santos Evelyn C. , Papadakis Konstantine
Published: December 2006

Ozonolysis studies of the monoenes of the fatty chain types in lipids of steer meibomian gland excreta (meibum) have confirmed earlier structural assignments based on gas liquid chromatography (GLC) retention data and have assisted in assigning complete structures to a group of recently identified ω‐hydroxy fatty acids. The ω‐hydroxy acids include straight‐chain monoenoic acids (85%), saturated anteiso and iso acids (13%), monoenoic acids of the latter group (1%) and, finally, saturates of the normal monoenoic acids (1%). All the fatty chains of meibum can be biosynthesized by a unified process of chain buildup to primary chain lengths of 12∶0–20∶0 for the straight evens, with 16∶0 predominating, 13∶0–21∶0 for the straight odds with 17∶0 predominating, i16∶0 to i28∶0 for the iso and ai17∶0 to ai29∶0 for the anteiso chain types; then Δ9 desaturation of each of these chain types; and finally chain elongation of 1–10 C2 units. Some chain degradation may also occur. The meibum lipid components involved are unsubstituted fatty acids, α‐OH fatty acids, ω‐OH fatty acids, fatty alcohols and some other lipid components incompletely characterized. The carbon skeletons are straight even, straight odd, iso and anteiso except that the α‐OH fatty acids are only straight even and straight odd and these chains are not elongated. All fatty chains are almost entirely saturated and monoenoic, the polyenes occurring in only trace amounts. Biosynthesis of the fatty chains of human meibum evidently occurs similarly, except that considerably more 18∶0 than 16∶0 fatty acids are built up by the fatty acid synthetase, before desaturation and extension.
Singlet oxygen in copper‐catalyzed lipid peroxidation in erythrocyte membranes
Authors: Ding Ai‐Hao , Chan Phillip C.
Published: December 2006

Lipid hydroperoxide was generated in human erythrocyte membranes by irradiation with near ultraviolet (UV) light in the presence of a photosensitizer, hematoporphyrin, but no production of 2‐thiobarbituric acid‐reactive materials (malonaldehyde and its precursors) was detected. Incubation of the irradiated membranes with CuSO4 led to increased levels of hydroperoxide and formation of malonaldehyde. Hydroperoxides were essential for initiating the Cu(II)‐catalyzed peroxidation as no significant activity was observed with nonirradiated membranes and Cu(II) unless an organic peroxide, either t‐butyl hydroperoxide or cumene hydroperoxide, was added. Catalytic activity was also found with Fe(II), but not with other metal ions tested. The peroxidation catalyzed with Cu(II) was partially inhibited by several singlet oxygen quenchers but was not affected by superoxide dismutase, catalase or OH• radical scavengers. The possible involvement of singlet oxygen in the Cu(II)‐catalyzed peroxidation reaction was further supported by a 3‐fold enhancement of malonaldehyde production in D2O.
Fatty acid desaturase specificity in tetrahymena
Authors: Conner Robert L. , Burtness Barbara , Ferguson Karen A.
Published: December 2006

The ciliate,Tetrahymena, was provided a supplement of the fatty acid [1‐14C] 18∶2Δ6,9. After a period of growth the cells were claimed, the lipids extracted, the polar lipids recovered and the mild alkali‐labile fatty acid methyl esters generated. The fatty acids were resolved by high pressure liquid chromatography (HPLC), the 18∶3Δ6,9,12 (γ‐linolenic acid) was recovered and its identity verified by high pressure liquid chromatography (HPLC), gas liquid chromatography (GLC), hydrogenation and oxidation. Fifty‐three percent of the cell‐associated label was found in γ‐linolenic acid; thus, a Δ12 fatty acid desaturase converts the 6,9 octadecadienoic acid to the 6,9,12 derivative. No carboxyl or methyl terminus restriction appears on Δ9 monoenoic or dienoic fatty acid desaturation in this cell as is found in higher plants and animals.
Phospholipid synthesizing enzymes of dermatophytes III. Glycerol kinase of dermatophytes
Authors: Kasinathan C. , Khuller G. K.
Published: December 2006

Glycerol kinase, the key enzyme for glycerol use in phospholipid synthesis, was identified in cytosolic fractions of 2 dermatophytes,Microsporum gypseum andEpidermophyton floccosum. Ammonium sulfate was observed to activate and stabilize this enzyme in both dermatophytes. Two pH optima, 8.0 and 10.5, were observed for both dermatophyte enzymes. Glycerol kinase fromM. gypseum was purified up to 33‐fold with a 225% recovery by ammonium sulfate precipitation and gel filtration. The molecular weight of the enzyme was ca. 4.5×105. It had 2 pH optima of 8.0 and 10.5. The enzyme had Km values of 0.35 mM and 2.3 mM for glycerol and ATP. Reactivity of the enzyme for various nucleotides was ATP>TTP>GTP>ITP=CTP=UTP. Kinetic studies showed the enzyme to catalyze the reaction by the ping‐pong mechanism. Fructose 1,6‐bisphosphate and glucose‐6‐phosphate inhibited the enzyme competitively, whereas glucose was not inhibitory.
Quantitative determination of Tri‐, Di‐,monooleins and free oleic acid by the thin layer chromatography‐flame lonization detector system using internal standards and boric acid impregnated chromarod
Authors: Tatara Takako , Fujii Tomiko , Kawase Tokuzo , Minagawa Motoi
Published: December 2006

The separation conditions for hydrolysates of triglycerides by lipase and their quantitative determination are discussed for a thin layer chromatography‐flame ionization detector system utilizing internal standards. The complete separation of glyceride hydrolysis mixtures (triolein 1,3‐diolein, 1,2‐diolein, 1‐monoolein and oleic acid) was achieved on a 3% boric acid‐impregnated Chromarod S‐II by development with benzene/chloroform/acetic acid (70∶30∶2, v/v/v) (mobile phase A) or hexane/ ether/acetic acid (70∶30∶1, v/v/v) (mobile phase B). Mobile phase B had an advantage over mobile phase A in terms of free space to add internal standards for simultaneous quantitation and was employed.p‐Hydroxybenzoic acid andp‐carboethoxy benzyl alcohol, which appeared between 1,2‐diolein and 1‐moloolein, were adopted as the internal standards. The calibration curves relating internal standards to each glyceride were all approximated by the equations Y=aXb giving high correlations. The method was applied to hydrolysis of triolein by pancreatic lipase.
The effect of dietary partially hydrogenated marine oils on desaturation of fatty acids in rat liver microsomes
Authors: Svensson Lennart
Published: December 2006

The influence of dietary partially hydrogenated marine oils on distribution of phospholipid fatty acids in rat liver microsomes was studied with particular reference to the metabolism of linoleic acid. Five groups of weanling rats were fed diets containing 20% (w/w) peanut oil (PO), partially hydrogenated peanut oil (HPO), partially hydrogenated Norwegian capelin oil (HCO), partially hydrogenated herring oil (HHO), and rapeseed oil (RSO) for 10 weeks. The partially hydrogenated oils were supplemented with linoleic acid corresponding to 4.6 cal % in the diets. Accumulation of linoleic acid and reduced amount of total linoleic acid metabolites were observed in liver microsomal phospholipids from rats fed partially hydrogenated oils as compared to PO feeding. The most striking effects on the distribution of ω6‐polyunsaturated fatty acids was obtained after feeding HHO, a marine oil with a moderate content oftrans fatty acids in comparison with HPO but rich in isomers of eicosenoic and docosenoic acids. Liver microsomal Δ6‐as well as Δ6‐desaturase activities as measured in vitro were reduced in rats kept on HHO as compared to PO dietary treatment. The results obtained suggest that the dietary influence of partially hydrogenated marine oils on the metabolism of linoleic acid might be better related to the intake of isomeric eicosenoic and docosenoic acids than to the total intake oftrans fatty acids.
Cholinephosphotransferase activity in human platelets
Authors: Gianfrancesco Goracci , Paolo Gresele , Arienti Giuseppe , Porrovecchio Patrizia , Nenci Giuseppe G. , Porcellati Giuseppe
Published: December 2006

Disrupted human platelets possess a cholinephosphotransferase activity (EC 2.7.8.2) whose properties have been studied in this work. The labeling of choline glycerophospholipid (CGP) from radioactive cytidine‐5′‐diphosphate choline (CDP‐choline) in vitro shows a maximum at pH 8.0 (using Hepes [4‐(2‐hydroxyethyl)‐piperazine‐1‐ethane‐2‐sulfonic acid] as a buffer) and is stimulated by Mn2+, Mg2+ and diacylglycerol. The enzymic activity is inhibited by Ca2+. The dependence of human platelet choline‐phosphotransferase upon CDP‐choline concentration does not follow the Michaelis‐Menten equation. CMP strongly inhibits the reaction. The functional implications of this newly discovered platelet activity are briefly considered.
Biliary and fecal steroid excretion in rats fed partially hydrogenated soybean oil
Authors: Sugano Michihiro , Ide Takashi , Kohno Mitsuko , Watanabe Midori , Cho Young‐J. , Nagata Yasuo
Published: December 2006

Male Wistar rats were fed cholesterol‐free or cholesterol‐enriched diets containing partially hydrogenated soybean oil with different levels oftrans‐fatty acids or unhydrogenated soybean oil at the 10% level. The linoleic acid content of hydrogenated fat diets was adjusted to 3.6% of the total energy. Hydrogenated fat diets contained 29% and 41%trans‐acids, mainly ast‐18∶1.Trans‐fats exerted no untoward effects on growth parameters, but increased liver weight. Dietary hydrogenated fats influenced neither the concentration nor composition of biliary steroids, irrespective of the presence or absence of cholesterol in the diet. In rats fed a cholesterol‐free diet, daily fecal output of neutral and acidic steroids was enhanced by hydrogenated fats and the magnitude of augmentation was proportional to the dietary level oftrans‐fatty acids. The increased fecal steroid excretion corresponded to an increase in total excreta. Hydrogenated fats also tended to enhance bile acid excretion when feeding a cholesterol‐enriched diet. The results suggest that dietarytrans‐fatty acids, in relation tocis‐polyunsaturated fatty acids, provoke demonstrable change in steroid homeodynamics.
Cooccurrence of C‐24 alkylated Δ7‐ and Δ5‐Sterols in the leaves ofBeta vulgarisin the leaves ofBeta vulgaris
Authors: Adler John H. , Salt Thomas A.
Published: December 2006

The 4‐desmethylsterols from the leaves ofBeta vulgaris are a mixture of Δ7‐sterols (71%) and Δ5‐sterols (29%). The Δ7‐sterols isolated are spinasterol (24α‐ethylcholesta‐7,22‐dien‐3β‐ol; 45%), 22‐dihydrospinasterol (24α‐ethylcholest‐7‐en‐3β‐ol; 24%), and avenasterol (24‐ethylcholesta‐7,24(28)‐dien‐3β‐ol; 1.5%). The Δ5‐sterols isolated are sitosterol (24α‐ethylcholest‐5‐en‐3β‐ol; 15%), 24ζ‐ethylcholesta‐5,22‐dien‐3β‐ol (7.5%), and 24ζ‐methylcholest‐5‐en‐3β‐ol (7%).
Determination of lipase specificity
Authors: Jensen Robert G. , DeJong Felice A. , Clark Richard M.
Published: December 2006

Specificity of lipases is controlled by the molecular properties of the enzyme, structure of the substrate and factors affecting binding of the enzyme to the substrate. Types of specificity are as follows. I. Substrate: (a) different rates of lipolysis of TG, DG, and MG by the same enzyme; (b) separate enzymes from the same source for TG, DG and MG. II. Positional: (a) primary esters; (b) secondary esters; and (c) all three esters or nonspecific hydrolysis. III. Fatty acid, preference for similar fatty acids. IV. Stereospecificity: faster hydrolysis of one primarysn ester as compared to the other. V. Combinations of I–IV. Lipases with these specificities are: Ia, pancreatic; Ib, postheparin plasma. IIa, pancreatic; IIb,Geotrichum candidum, for fatty acids withcis‐9‐unsaturation, and IIc,Candida cylindracea. III,G. candidum for unsaturates. IV.sn‐1, postheparin plasma andsn‐3 human and rat lingual lipases. V. Rat lingual lipase. Methods for determination involve digestion of natural fats of known structure and synthetic acylglycerols followed by analysis of the lipolysis products. All of the types of specificity have been detected with use of synthetic acylglycerols. Detection of stereospecificity requires enantiomeric acylglycerols which are difficult to synthesize, so other methods have been developed. These involve the generation of 1,2‐(2,3) DG and resolution of the enantiomers. Trioleoylglycerol or racemic TG can be used as substrates. If the lipase is stereospecific, then either thesn‐1,2‐ or 2,3‐enantiomer will predominate. The relative amounts of the enantiomers can be determined by measurement of specific rotation, and nuclear magnetic resonance spectra. The DG can also be separated by conversion to phospholipids and hydrolysis with phospholipases A‐2 or C. Applications of these procedures are discussed and data on the specificity of various lipases presented.
Enhanced incorporation of exogenous arachidonic acid into phosphatidylinositol and other phospholipids during the early stages of thrombin‐induced aggregation in gerbil platelets
Authors: Agwu D. E. , Johnstone I. , Crane S. , Holub B. J.
Published: December 2006

The degradation of platelet phospholipids via phospholipase activity is known to occur during thrombin‐induced platelet aggregation. Both phosphatidylinositol and phosphatidylcholine are considered to be sources of the released arachidonic acid which becomes a substrate for prostaglandin and thromboxane A2 formation. In this work, the effect of thrombin on the incorporation of exogenous arachidonic acid into platelet membrane phospholipids was studied. Suspensions of gerbil platelets were incubated in aggregometer cuvettes with [14C] arachidonic acid in the absence or presence of thrombin, and product formation was monitored by thin layer chromatography and scintillation counting. Within 30 sec, the entry of arachidonic acid into phosphatidylinositol was increased by 165% in thrombin‐stimulated platelets over controls. Under identical conditions, the incorporation into phosphatidylcholine was increased by only 57%. These results suggest that the incorporation of exogenous arachidonic acid via lysophosphatidylinositol and lysophosphatidylcholine acyltransferase activities may be intimately associated with thrombin‐induced platelet aggregation in the gerbil.
A complete separation of lipids by three‐directional thin layer chromatography
Authors: Kramer J. K. G. , Fouchard R. C. , Farnworth E. R.
Published: December 2006

A novel three‐directional thin layer chromatography (TLC) method is reported by which all the polar and neutral lipids are isolated on a single TLC plate. Following resolution of the phospholipids by two‐directional TLC, lipids are visualized by ultraviolet light after spraying with 2′,7′‐dichloro‐fluorescein. A line is drawn across the plate, parallel to the second direction of development, separating the resolved phospholipids and the neutral lipids concentrated along the solvent front. The TLC plate is then chromatographed in the reverse direction of the second development to resolve the neutral lipids. By exposing the lipids to HCl fumes after the first development, the plasmalogen content of the lipids may also be determined. This new technique is rapid and lends itself to qualitative and quantitative analyses of total lipids.
Metazoan lipids: An unusual association of saturated sterols with relatively saturated fatty acids in the cilia ofCiona intestinalis
Authors: Morris Robert J. , Bone Q.
Published: December 2006

Cilia from the tunicateCiona intestinalis have been analyzed for, their biochemical compositions. Cholestanol is found to be a major steroidal component, whereas the phospholipids are composed mainly of C14−C18 saturated fatty acids. The saturated nature of the lipids may be related to specific requirements of the ciliary membrane.
Fatty acids in plasma and red cell membranes in normal humans
Authors: Manku M. S. , Horrobin D. F. , Huang Y‐S. , Morse N.
Published: December 2006

A detailed study was made of the fatty acid composition of plasma triglycerides, free fatty acids, phospholipids, red cell total phospholipids, phosphatidylcholine and phosphatidylethanolamine in 32 normal males and 18 normal females. No sex differences could be detected. There were substantial differences in the compositions of the various fractions and long‐chain polyunsaturated fatty acids were particularly important in the red cells.
Oxidation of lipids: III. Oxidation of methyl linoleate in solution
Authors: Yamamoto Yorihiro , Niki Etsuo , Kamiya Yoshio
Published: December 2006

The effects of oxygen pressure, substrate concentration and solvent on the rate and products of oxidation of methyl linoleate were studied at 50 C with azobisisobutyronitrile as a radical initiator. The absolute and quantitative numbers for oxygen uptake, substrate disappearance, and formation of conjugated diene and hydroperoxides were measured. Under the present conditions, 4 conjugated diene hydroperoxides, 13‐hydroperoxy‐9‐cis, 11‐trans‐(2a), 13‐hydroperoxy‐9‐trans, 11‐trans‐(3a), 9‐hydroperoxy‐10‐trans, 12‐cis‐(4a), and 9‐hydroperoxy‐10‐trans, 12‐trans‐(5a) octadecadienoic acid methyl esters, were formed almost quantitatively. The rate of oxidation decreased with decreasing oxygen pressure. However, the ratio ofcis,trans totrans,trans hydroperoxides, (2a+4a)/(3a+5a), was independent of oxygen pressure, and this ratio increased with increasing methyl linoleate concentration, as found recently by Porter. Further, the rate of oxidation and the ratio ofcis,trans/trans,trans hydroperoxides were dependent on solvent and increased with an increase in dielectric constant of solvent. A mechanism of methyl linoleate oxidation consistent with these results is discussed.
Modulation of tissue prostaglandin synthesizing capacity by increased ratios of dietary alpha‐linolenic acid to linoleic acid,
Authors: Marshall Lisa A. , Johnston Patricia V.
Published: December 2006

Semipurified diets containing ratios of α‐linolenic acid (18∶3ω3) to linoleic acid (18∶2ω6) of 1/32, 1/7, 1/1, and 3.5/1 in the form of corn oil, soybean oil, soybean/linseed oil mix and linseed oil were fed to rats for 2 months. The first 3 diets were fed to another group of rats for 4 months and to a group through the second generation. Fatty acid analysis of liver and spleen ethanolamine glycerophosphatide revealed that, as the level of 18∶3ω3 in the diet increased, the elongated, desaturated metabolites of the ω6 series decreased and the ω3 series increased. Noteworthy was the depression in the amount of the precursor of the 2‐series prostaglandins (PG) as the ω3 levels increased. Synthesis of PG by liver of rats fed 2 or 4 months markedly decreased, but at 2 months in thymus and spleen, it showed a trend toward decreasing only. Brain slices showed no decrease in PGF2α synthesis after 4 months, but did decrease significantly after feeding the diets to the second generation. Synthesis of PGE2 by spleen homogenate from the second generation also significantly decreased. The replacement of ω6 series fatty acids by ω3 series is explained by the effective competition of 18∶3ω3 over 18∶2ω6 for the Δ6 desaturase. Depressions in PG synthesis by high dietary 18∶3ω3 is explained by the competitive inhibition of the PG synthetase complex by 20∶5ω3 as well as by the decreased levels of 20∶4ω6.
The effect of dietary lipid on the lipoprotein status of the mongolian gerbil
Authors: Leach Andrea B. , Holub Bruce J.
Published: December 2006

The Mongolian gerbil,Meriones unguiculatus, may be a suitable animal model for the investigation of dietary lipid effects on cholesterol metabolism. The effects of dietary cholesterol, and its possible interaction with the type of dietary fat, on the lipoprotein status of this animal have not been examined previously. In the present research, the effects of adding 0.5% cholesterol to diets high in saturated (19.5% beef tallow: 0.5% safflower oil) or polyunsaturated (20% safflower oil) fats on the lipoprotein status of the gerbil were determined after 11 and 22 days of feeding. Lipoproteins (VLDL, LDL and HDL) were separated by sequential ultracentrifugation. Their cholesterol, phospholipid and protein concentrations were determined colorimetrically. In the absence of 0.5% cholesterol, safflower oil lowered the concentration (mg/100 ml) of cholesterol in each of the VLDL, LDL and HDL relative to beef tallow (BT) without greatly influencing the cholesterol distribution amongst them. The HDL carried the majority of the serum cholesterol and the VLDL transported the smallest amount. However, inclusion of 0.5% dietary cholesterol resulted in a redistribution of cholesterol amongst the lipoproteins so that the VLDL and LDL became the major and the HDL the minor carriers. Dietary cholesterol also brought about a rise in the VLDL and LDL concentrations (mg/100 ml) of cholesterol, phospholipid and protein and altered the VLDL and LDL compositions. No such changes were observed in the HDL, indicating that the HDL are relatively resistant to any of the possible effects of cholesterol feeding measured in this experiment. The specific mechanisms responsible for the changes observed in the lipoprotein status of the gerbil remain to be elucidated.
Lung surfactant and fatty acid composition of lung tissue and lavage of rats fed diets containing different lipids
Authors: Alam Syed Q. , Alam Bassima S.
Published: December 2006

Two nutritional models, essential fatty acid (EFA) deficiency and the feeding of saturated vs unsaturated fats, were used to determine the effects of dietary lipids on the fatty acid composition of rat lung and lavage. Semipurified diets containing 7% corn oil, 7% hydrogenated coconut oil (EFA‐deficient), 10% butter or 10% safflower oil were fed to dams during lactation and thereafter to their offspring for a total of 24 weeks. Lipids were extracted from the lung lavage and lung tissue and their fatty acid composition was determined. The content of dipalmitoylphosphatidylcholine (DPPC), the main surfactant in the lungs, was also determined. The results show that the levels of DPPC in the lungs of rats fed 10% butter decreased although the decrease in the EFA‐deficient rats was greater. Comparing rats fed butter with those fed corn oil, there were also modifications in the fatty acid composition of the total lipids and phospholipids of lung tissue and lavage as well as in phosphatidylcholine, phosphatidylethanolamine and phosphatidylinositol +phosphatidylserine fractions isolated from the lung tissue. The changes in fatty acid composition were somewhat fewer in rats fed butter then in those fed an EFA‐deficient diet. The results suggest that a marginal EFA deficiency produced in rats by long‐term feeding of 10% butter may account for the reduction in DPPC levels and in the changes in fatty acid composition in the lung tissue and lavage.
Complete assignment of the carbon‐13 NMR spectrum of oiticica oil: Interpretation of chemical shifts in conjugated systems
Authors: Bergter L. , Seidl P. R.
Published: December 2006

All absorptions on the carbon‐13 spectrum of α‐ and β‐eleostearic and licanic acid esters are assigned. A combination of off‐resonance decoupling and lanthanide‐induced shifts coupled to polarization by a remote keto group was necessary to establish the correct order of conjugated olefinic carbon atoms. By themselves, none of these techniques would have sufficed to reach the cortect conclusions. Steric effects are accounted for but may lead to wrong results if proper consideration is not given to other factors.
High field13C nuclear magnetic resonance spectrum of the olefinic carbons of the triglycerides of palm oil
Authors: Ng Soon
Published: December 2006

In the triglycerides of palm oil (or any vegetable oil or fat), an unsaturated fatty acid (oleic or linoleic) attached to the 2‐glycerol carbon can be distinguished from one attached to the 1‐ or 3‐glycerol carbon by high (or medium) field13C nuclear magnetic resonance (NMR) analysis of the olefinic carbons. The chemical shift difference of the olefinic carbons in the fatty acid chain is characteristic of the chain's glycerol position and can therefore be used to identify the glycerol position of an unsaturated fatty acid in the triglyceride.
Phospholipid studies of marine organisms: V1 new α‐methoxy acids fromHigginsia tethyoides
Authors: Ayanoglu Eser , Popov Simeon , Kornprobst J. M. , Aboud‐Bichara Amira , Djerassi Carl
Published: December 2006

The phospholipids of the demospongeHigginsia tethyoides are shown to have at least 16 long‐chain α‐methoxy acids, which represent a new class of fatty acids. Among them are the saturated α‐methoxy acids containing 19–24 carbon atoms. The monounsaturated compounds are 2‐OMe‐Δ17‐24:1, 2‐OMe‐Δ18‐25:1, 2‐OMeΔ19‐26:1 and 2‐OMe‐Δ21‐28:1. The major diunsatured ones were shown to be 2‐OMe‐Δ5, 19‐26:2 and 2‐OMe‐Δ7, 21‐28:2. Small amounts of 2‐OMe‐23∶1, 2‐OMe‐26∶3; 2‐OMe‐27∶1 and 2‐OMe‐28∶3 were also encountered. Structures of the minor monounsaturated compounds were tentatively assigned as 2‐methoxy‐16‐tricosenoic acid and 2‐methoxy‐20‐heptacosenoic acids. The double bonds of the fatty acids show all‐cis configuration. Circular dichroism measurements indicate an R‐configuration for the α‐methoxy acids. The major component of the total phospholipid acid mixture is 5,9,23‐triacontatrienoic acid. Possible biosynthetic routes to these unusual phospholipid acids are discussed. The major phospholipids were phosphatidylethanolamine, phosphatidylglycerol and phosphatidylserine. The distribution of fatty acids among the phospholipids was also investigated.
Lipolysis of corn, peanut and randomized peanut oils
Authors: Kim Hong K. , Kritchevsky David
Published: December 2006

Corn oil, peanut oil and randomized peanut oil exhibit different atherogenic potentials; peanut oil being more atherogenic than the other oils. This study was conducted to ascertain if the atherogenicity of these oils was related to their rates of lipolysis. Using both pancreatic lipase and milk lipoprotein lipase (LPL), it was shown that the rated of lipolysis were corn oil>peanut oil>randomized peanut oil. The rates of lipolysis are not related to atherogenicity and may be affected by the distribution of long‐chain saturated fatty acids in the component triglycerides.