bluuebunny/crossref_metadata_2025 huggingface dataset:
Isomerization of L‐glyceraldehyde to dihydroxyacetone during glyceride synthesis by rat liver microsomes
Authors: Rao G. Ananda , Puleo L. E. , Sorrels M. F. , Reiser Raymond
Published: November 2006

L‐glyceraldehyde is converted to phosphatidic acid by the action of rat liver microsomal enzymes and glycerol kinase in the presence of fatty acid, ATP, CoASH and NADH. L‐glycerol 3‐phosphate is not an intermediate in this synthesis since microsomes in the presence of NADH neither reduce L‐glyceraldehyde nor, in the additional presence of glycerol kinase and ATP, convert it to L‐glycerol 3‐phosphate. However dihydroxyacetone is produced when L‐glyceraldehyde is incubated with microsomes. This was shown enzymatically by the subsequent conversion to dihydroxyacetone phosphate which was confirmed by the oxidation of NADH in the presence of glycerol 3‐phosphate dehydrogenase. Isomerization of L‐glyceraldehyde and the synthesis of dihydroxyacetone phosphate may be one of several possible mechanisms in the conversion of the triose to either glucose or glycerideglycerol which has been reported to occur in tissue.
Structural comparison between triglycerides and phospholipids from pig kidney
Authors: Hagen Per‐Otto
Published: November 2006

The compositional specificity of the major diacyl phosphatides, plasmalogens and triglycerides of pig kidney has been determined. The triglycerides have been shown to be esterified predominantly with saturated fatty acids in the 2 position while the phosphatides have predominantly unsaturated fatty acids in this position. Such complete “inversion” of the structure of triglycerides and phospholipids is not normally seen in mammalian tissue and suggests that the synthesis of structural polar lipids involves other steps than the reaction of a diglyceride with CDP‐ethanolamine or CDP‐choline. This marked difference in the fatty acid distribution of the polar lipids and triglycerides of the pig kidney may render this tissue especially suitable for studies on the turnover and synthesis of structural lipids.
Enzymatic conversion of 5α‐cholest‐8(14)‐en‐3β‐ol to 5α‐cholesta‐8, 14‐dien‐3β‐ol
Authors: Lutsky B. N. , Schroepfer G. J.
Published: November 2006

[3α‐3H]‐Cholest‐8(14)‐en‐3β‐ol was incubated with a 10,000 x g supernatant fraction of a rat liver homogenate. The enzymatic formation of labeled cholesta‐8, 14‐dien‐3β‐ol was indicated by the results of studies employing column chromatographic and cocrystallization techniques.
2‐Monoglyceride as an aid to the absorption of cholesterol into the thoracic lymph
Authors: Klauda Harry C. , Quackenbush Forrest W.
Published: November 2006

Absorption of radioactive cholesterol given in triolein was nearly three‐fold that of a similar dose given in ethyl oleate or oleic acid. The difference appears to reflect a need for monoglyceride, since addition of 2‐monoolein to ethyl oleate improved cholesterol absorption.
Relative incorporation of acetate and glucose into glycerides ofGlomerella cingulata
Authors: Jack R. Cecil , Harkness S. H.
Published: November 2006

Cultures of the fungusGlomerella cingulata were pulse‐labeled for 30 min with 1‐14C‐acetate at ages from 2 to 12 days old. The greatest incorporation into triglycerides and phosphoglycerides occurred in the youngest cultures, but more of the radioactive acetate was diverted to the phosphoglycerides than to the triglycerides in these cultures.

In another series of experiments the incorporation of 1‐14C‐acetate or 2‐14C‐glucose into the triglycerides and phosphoglycerides of the fungus was investigated at 15‐minute intervals for 1 hr. Hydrolysis of the two classes of glycerides revealed some labeling of glycerol from acetate; but, not surprisingly, acetate was incorporated into the fatty acid moieties to a greater extent than into the glycerol moieties, and there was relatively greater incorporation of 2‐14C‐glucose into glycerol than into fatty acids. Some relationships of these results to the growth and development ofG. cingulata are suggested, and implications relative to control mechanisms are pointed out.
Glyceride structure ofCardamine impatiens L. Seed oil
Authors: Mikolajczak K. L. , Smith C. R. , Wolff I. A.
Published: November 2006

A group of unusual triglycerides, in which one of the acyl groups is a vicinal dihydroxy acid with one of the hydroxyl groups acetylated, has been isolated fromCardamine impatiens L. (Cruciferae) seed oil. Hydrolysis of these triglycerides with castor bean lipase facilitated isolation and identification of a mixture of C18, C20, C22, and C24 hydroxy acetoxy fatty acids. Pancreatic lipase hydrolysis data revealed that these monoacetylated dihydroxy acid residues are esterified exclusively with one of the α‐positions of the glycerol moiety. The remaining acyl groups are comprised of ordinary C18 unsaturated acids (which occupy 98% of the β‐position), palmitic acid, and C20, C22, and C24 monoenoic fatty acids.
Tritium and14C counting in tissue samples by using liquid scintillation method
Authors: Parekh C. K. , Eigen E.
Published: November 2006

The combustion method has been modified to increase the recovery of tritiated water after combustion of a tritium‐labeled tissue sample. This was accomplished by cooling the bottom of the combustion flask in a dry ice‐acetone bath while irradiating the top with an infrared lamp. The procedure resulted in at least 92% to 102% recovery of the tritiated water. The NCS solubilizer was found to be superior to hyamine for solubilizing14C labeled tissue samples. The samples yielded light yellow‐colored solutions when incubated for 15 hr at 50–55C. The counting efficiency of this solution was 75% or higher.
Sterol metabolism. III. Sterols of marine waters
Authors: Stephen Matthews W. , Smith Leland L.
Published: November 2006

The detection and tentative identification of three sterols, cholesterol, stigmasterol, and β‐sitosterol, in hexane extracts of Gulf of Mexico waters has been achieved by using thin‐layer and gas chromatographic procedures. The identifications are assigned on the basis of chromatographic properties of the free sterols, of their acetates, and of their trimethylsilyl ethers.
The lipids of the common house cricket,Acheta domesticus L. I. Lipid classes and fatty acid distribution
Authors: Hutchins Roderick F. N. , Martin Michael M.
Published: November 2006

The lipids of the common house cricket,Acheta domesticus L., have been examined with the following results. The fatty acids associated with the lipid extracts do not change significantly from the third through the eleventh week of the crickets' postembryonic life. The major fatty acids are linoleic (30–40%), oleic (23–27%), palmitic (24–30%), and stearic acids (7–11%). There are smaller amounts of palmitoleic (3–4%), myristic (∼1%), and linolenic acids (<1%). The fatty acid composition of the cricket lipids reflects but is not identical to the fatty acids of the dietary lipids: linoleic (53%), oleic (24%), palmitic (15%), stearic (3%), myristic (2%), and linolenic acid (2%).

The amount of triglycerides present in the crickets increases steadily from the second through the seventh or eighth week of postembryonic life, then drops sharply. Other lipid classes, such as hydrocarbons, simple esters, diglycerides, monoglycerides, sterols, and free fatty acids remain about constant. The composition of the fatty acids associated with the tri‐, di‐, and monoglycerides and the free fatty acid fraction are all about the same. The fatty acids associated with the simple esters are high in stearic acid.
Fatty acid composition ofClaviceps species. Occurrence of (+)‐threo‐9, 10‐dihydroxystearic acid
Authors: Morris L. J.
Published: November 2006

The fatty acids from sclerotia ofC. purpurea and of four otherClaviceps species have been examined chromatographically, and all contain greater or lesser amounts of various oxygenated fatty acids.C. sulcata was the most unusual in that it contained some 60% of (+)‐threo‐9, 10‐dihydroxystearic acid.
Hydrophobic enzymes in hydrocarbon degradation
Authors: Van Der Linden A. C. , Van Ravenswaay Claasen J. C.
Published: November 2006

Pseudomonas aeruginosa (strain 473) constitutively contains an NADP‐linked alcohol dehydrogenase. This enzyme is believed to function only in assimilative processes, because growth on primary alcohols, α,ω‐diols orn‐alkanes induces another alcohol dehydrogenase which is not linked to a pyridine nucleotide. The inducible enzyme reduces bovine cytochromec and various dyes, but not oxygen. At least two variants of the dissimilative NAD(P)‐independent enzyme can be induced by choosing the substrate used for growth. The main difference between the two variants is their different capacity to oxidize ethanol. A noteworthy property of the inducible enzyme is its hydrophobic character. Some of its consequences in paraffin dissimilation are discussed. The paraffin hydroxylase system of the heptane‐grownPseudomonas was found to hydroxylate various types of hydrocarbons and thus shows a low substrate specificity. On the other hand, remarkable specificities were also encountered; in some cases only thetrans configuration of a substrate was hydroxylated. With respect to the site of hydroxylation, the enzyme system was quite specific, even to the extent that, in appropriate cases, the hydroxyl group was introduced in thetrans‐position only. The results obtained with the enzymatic hydroxylations, including some of the specificities encountered, can be explained by assuming that substrate molecules capable of attaining a planar conformation are bound by hydrophobic forces to the enzyme surface.
Metabolism of alkane by yeast
Authors: Lebeault J. M. , Azoulay E.
Published: November 2006

We demonstrated two NAD+‐linked alcohol dehydrogenases in cell free extracts ofCandida tropicalis grown onn‐tetradecane. Comparative studies of localization, properties and regulation indicate that these enzymes are involved in two different pathways ofn‐alkane metabolism, one cytoplasmic and the other mitochondrial. Kinetic properties, such as the variation of the Km and Vmax as a function of substrate chain length of the soluble NAD+‐linked alcohol dehydrogenase, might involve hydrophobic interactions between the substrate and the enzyme.
Microbial subterminal oxidation of alkanes and alk‐1‐enes
Authors: Allen J. E. , Forney F. W. , Markovetz A. J.
Published: November 2006

Oxidation ofn‐alkanes and alk‐1‐enes by aPenicillium species andPseudomonas aeruginosa resulted in the formation of intermediates arising from the oxidation of methylene groups. A catabolic pathway involving oxidation of the hydrocarbon to a secondary alcohol and the corresponding ketone, followed by the formation and subsequent cleavage of an ester intermediate is presented.
The effect of undernutrition on the development of myelin in the rat central nervous system
Authors: Fishman Marvin A. , Madyastha Prema , Prensky Arthur L.
Published: November 2006

Newborn rats were segregated into litters of 6 and 22 pups. Undernourished groups were maintained for 21 and 53 days at which time a portion of each group was sacrificed and the remainder refed until 121 days. The amount of myelin isolated from the central nervous system was decreased in nutritionally deprived animals but there was little change in its chemical composition or intereference in the normal chemical maturation of the membrane. The only consistent change was a reduction in phosphatidyl ethanolamine plasmalogen. This deficit tended to be corrected by nutritional rehabilitation and was most complete in those animals refed ad lib. diets for the longest time periods prior to sacrifice. The relatively normal chemical composition of myelin obtained from undernourished animals differs from changes described in myelin membranes isolated from patients with destructive or degenerative diseases of the nervous system. This seems to be further evidence that the reduction in myelination in undernutrition is a result of decreased synthesis of the membrane.
Ether‐containing lipids of the slime mold,Physarum polycephalum: I. Characterization and quantification
Authors: Poulos Alfred , Le Stourgeon Wallace M. , Thompson Guy A.
Published: November 2006

Rapidly growing plasmodia of the acellular slime mold,Physarum polycephalum, contain large amounts of ether‐linked lipids. The ether bonds occur principally in the phospholipids, where plasmalogens account for 21–24 mole per cent of the total and alkyl ether phospholipids comprise 12 mole per cent of the total. Plasmalogens account for over half of the ethanolamine phosphatides, while the alkyl ether derivatives are more uniformly distributed among the various phospholipid fractions. The 16 carbon side chain is by far the major component of both the saturated and the α,β‐unsaturated ether derivatives. The nature and amounts of ether lipids present inPhysarum add to the growing evidence that Myxomycetes are more closely related to protozoa than to fungi.
Effects of su‐13437, a new hypolipidemic drug, upon synthesis in vivo of hepatic and carcass total fatty acids and total cholesterol
Authors: Cenedella Richard J.
Published: November 2006

The present study is directed toward obtaining information on the metabolic effects and on the mode of action of CIBA‐Su‐13437, a new hypolipidemic phenolic ether structurally related to clofibrate. The ability of Su‐13437 to affect the net formation of lipids in vivo was studied by measuring the total incorporation of intraperitoneally injected 1,2‐14C‐sodium acetate and uniformly labeled14C‐glucose into total fatty acids and total cholesterol by the liver and carcass of control and Su‐13437‐treated mice. Treated mice received Su‐13437 orally at 25, 100 or 250 mg/kg/day for 14 or 15 consecutive days. Treatment with Su‐13437 resulted in pronounced enlargement of the liver and significant reductions in the plasma levels of triglycerides and total cholesterol. Essentially all of the observed metabolic effects of Su‐13437 were confined to the liver. At all doses studied, in addition to liver enlargement, there were large increases in incorporation of both14C‐acetate and14C‐glucose carbon into hepatic total fatty acids; marked increases in hepatic total fatty acid content; and decreases in the liver's relative cholesterol content of up to 30% with little or no effect upon the net synthesis of cholesterol per gram of liver. These observations are interpreted as indicating that Su‐13437 lowers plasma triglyceride and cholesterol levels by means other than net inhibition of fatty acid and cholesterol formation by either hepatic or extrahepatic tissues.
Mass spectrometric analysis of long chain alk‐1‐enyl ether esters and alkyl ether esters of diols
Authors: Kramer John K. G. , Baumann Wolfgang J. , Holman Ralph T.
Published: November 2006

The mass spectra of homologous series of long chain alk‐1‐enyl ether esters and alkyl ether esters of short chain diols were determined, and general patterns of fragmentation were established. Both types of diol lipids yielded ions characteristic of the alkoxy or alk‐1‐enyloxy moiety and the acyl moiety, as well as ions indicative of the constituent short chain diol. Prominent ions were formed from both types of ether esters due to the loss of the alkoxy or alk‐1‐enyloxy moieties giving rise to ions for which cyclic structures are proposed. High resolution mass spectrometry and deuterium labeling techniques were used to verify the composition of ions and to substantiate fragmentation mechanisms.
Separation of lipids containing phytanic acid by thin‐layer chromatography
Authors: Karlsson K. ‐A. , Nilsson K. , Pascher I.
Published: November 2006

Cholesteryl phytanate and triglycerides containing phytanic acid were separated from their normal fatty acid analogs by thin‐layer chromatography. The presence of the branched‐chain fatty acid makes the lipid less polar, and this effect becomes more pronounced as the number of phytanic acid residues in the triglycerides is increased. Phytanic acid was prepared from commercial phytol by catalytic hydrogenation, followed by catalytic oxidation. It contained 5% pristanic acid.
Fatty acids of unusual double‐bond positions and chain lengths found in rat skin surface lipids
Authors: Nicolaides N. , Ansari M. N. A.
Published: November 2006

The fatty acids of rat skin surface lipids comprise four main skeletal types of chains which occur both as saturates and monoenes and range from C12 to C38: straight even, straight odd, iso and anteiso (the latter two identified by GC retention data only). Two unidentified series of branched monoenes also occur in trace amounts.

Reductive ozonolysis of monoenes reveals two characteristic double‐bond position patterns, one for the straight even chain series and the other for the straight odd chain series. The straight even chain pattern comprises four series, of which ω7 ≫ω9>ω5>ω11; the straight odd chain series in contrast shows a large number of ω series with irregular distribution. The biosynthesis of the even chain fatty acid monoenes can be thought of as occurring in two stages: synthesis of 14∶Δ9, 16∶Δ9, 18∶Δ9 and 20∶Δ9, with 16∶Δ9 predominating; elongation of these chains mostly by 1, 2, or 3 C2 units but up to the unusually long lengths by 11 C2 units. For the formation of the former, two schemes by known pathways are proposed.

Iso and anteiso chains which are nearly all saturated comprised 1/3 the total fatty acids.
The incorporation of14C‐glycerol into different species of diglycerides and triglycerides in rat liver slices
Authors: Hill Edward E. , Lands William E. M. , Slakey Sister P. M.
Published: November 2006

The relative rates of de novo synthesis of species of diglycerides and triglycerides from14C‐glycerol were examined in rat liver slices. Diglycerides containing one or two double bonds per molecule and triglycerides containing four or more double bonds per molecule represented 70% and 60% respectively of the newly synthesized diglycerides and triglycerides. The newly synthesized triglycerides were more unsaturated than the endogenous triglycerides. Our results suggest that a nonrandom synthesis of species of diglycerides occurred followed by an almost random utilization of the various diglyceride species for the biosynthesis of triglycerides.
Predicting the positional distribution of docosahexaenoic and docosapentaenoic acids in aquatic animal triglycerides
Authors: Litchfield Carter
Published: November 2006

The positional distribution of 22∶6 and 22∶5 in aquatic animal triglycerides can be predicted by simple proportionality equations of the typey=kx. The mole % 22∶6 at the 1, 2, or 3 position (y) is obtained by multiplying the proportionality constant for that position (k1,k2, ork3) times the mole % 22∶6 in the total triglycerides (x). For fish and invertebrate triglycerides,k1=0.28,k2=2.06, andk3=0.66. For marine mammal blubber triglycerides,k1=0.94,k2=0.22, andk3=1.84. The same equations apply to both 22∶6 and 22∶5.
Hydroxy fatty acids from cerebrosides of the central nervous system: GLC determination and mass spectrometric identification
Authors: Capella P. , Galli C. , Fumagalli R.
Published: November 2006

A method has been developed for GLC determination of hydroxy fatty acids (HFA) from cerebrosides of the central nervous system.

Identification of HFA present in complex biological mixtures was achieved by the use of the combination gas chromatography— mass spectrometry. GLC separations and mass spectrometric determinations were carried out on the trimethylsilyl derivatives of HFA, which show excellent GLC characteristics and favorable cleavages to determine the position of OH groups on the aliphatic chain. The mass spectra of these derivatives present some unusual rearrangement ions, whose composition has been studied with the aid of deuterium labeled analogs.
Dietary induced alterations in swelling characteristics and endogenous phospholipase A2 activity of rat liver mitochondria
Authors: Waite Moseley , Van Golde L. M.
Published: November 2006

The present study describes the rapid alterations in the fatty acid patterns of phosphatidyl choline and phosphatidyl ethanolamine from rat liver mitochondria induced by corn oil feeding to EFA‐deficient rats. Simultaneous changes occurring with comparable rates were observed in the swelling properties and phospholipase A2 activity of the mitochondria. Mitochondria isolated from the liver of EFA‐deficient rats exhibited a high tendency to swell and a high phospholipase A2 activity in comparison with those prepared from normal rat liver. Feeding of corn oil for 48 hr to the EFA‐deficient rats completely reduced this high rate of swelling and phospholipase A2 activity to the normal level. In the same time eicosatrienoic acid, a characteristic fatty acid constituent of phospholipids from EFA‐deficient animals, was replaced by the more common fatty acids, linoleic and arachidonic. The possible relationship between fatty acid constituents of phospholipids, swelling properties and phospholipase A2 activity in rat liver mitochondria are discussed.
Lipids and the pill
Authors: Alfin‐Slater R. B. , Aftergood L.
Published: November 2006

The widespread use of anovulatory compounds and the well‐known effects of sex hormones on various aspects of metabolism prompted this review of our work and the work of others on observed changes in lipid metabolism resulting from the administration of oral contraceptives and their components. In the rat, female sex hormone administration results in a decreased plasma cholesterol level, an accumulation of cholesterol in liver and a decreased hepatic cholesterol biosynthesis. On the other hand, cholesterol biosynthesis is enhanced in ovaries and adrenals. There is also a diminished alpha lipoprotein content and a corresponding decrease in the alpha/beta lipoprotein ratio. In some cases these changes are comparable to those observed during pregnancy. The results of sex hormone administration to women are more variable. In this case the most often observed effect is hypertriglyceridemia. Changes in lipoprotein content and distribution are also evident and may be the result of changes in metabolism in the liver, e.g., lipid synthesis or lipid transport from liver to plasma and tissues, or both. Many of these changes may be mediated indirectly through the action of estrogenprogestin on other hormones. In both species the effects of oral contraceptives are attributable principally to the estrogen component. The combination of estrogen with progestin compounds, which constitutes the oral contraceptive, modifies the effects of estrogen administered alone.
Fatty acid synthesis in rat testes injected intratesticularly or incubated with 1‐14C acetate
Authors: Evans O. B. , Zseltvay Richard , Whorton Richard , Coniglio John G.
Published: November 2006

Fatty acid synthesis was studied in testes of young and adult rats either injected intratesticularly or incubated with 1‐14C acetate. The pattern of14C incorporation into lipids and individual fatty acids in the two age groups was similar but results obtained with intratesticular injection differed considerably from those obtained in the in vitro studies. In the former more than 70% of the14C incorporated in total lipids was in phosphatides, with about 15% in triglycerides and only minor amounts in cholesteryl esters and free fatty acids. Most of the14C incorporated into total fatty acids was in saturated acids (predominantly 16∶0). A small amount of14C was in the higher polyenes and there was a progressive increase with time after acetate injection in the14C content of 22∶5 W6. In testes incubated with 1‐14C acetate, the phosphatide, triglyceride, and free fatty acid fractions had similar amounts of14C. In the total fatty acid fraction about 40% of the incorporated14C was in saturated acids (predominantly 14∶0 and 16∶0) and about 50% in the higher polyenes. Twenty carbon polyenes and 22∶5 W6 had significant14C incorporation, but most of the14C was in 22∶4 W6. About 80% of the14C in the latter compound was in the carboxyl carbon, indicating its origin from endogenous 20∶4 W6 elongated by the added 1‐14C acetate used as substrate. The14C 22∶4 was present predominantly in the triglyceride and phosphatide fractions with minor amounts in other lipids.14C‐labeled compounds of retention time greater than 22∶5 were also present in all lipid fractions.
Fluorescent products of lipid peroxidation of mitochondria and microsomes
Authors: Dillard C. J. , Tappel A. L.
Published: November 2006

Liver microsomes and mitochondria and heart sarcosomes from rats fed diets with varying α‐tocopherol concentrations and lipid contents were peroxidized over a 6 hr time period. Lipid peroxidation was measured by absorption of oxygen, production of thiobarbituric acid (TBA) reactants and by development of fluorescence. The spectral characteristics of the fluorescent compounds were the same for all peroxidizing systems; the excitation maximum was 360 nm and the emission maximum was 430 nm. As time of peroxidation increased, uptake of oxygen and production of fluorescent compounds increased. These two parameters as well as production of TBA reactants were dependent upon dietary antioxidant and all three had an inverse relationship with the amount of dietary α‐tocopherol. The relationship between absorption of oxygen and development of fluorescent compounds was also dependent upon dietary polyunsaturated fats (PUFA). Subcellular particles from animals fed higher levels of PUFA produced more fluorescent products per mole of oxygen absorbed than did those from animals on a diet with lower PUFA content. TBA reacting products increased with time during the initial phase of peroxidation: in the microsomal systems their production stabilized or decreased by 4–6 hr of peroxidation. Using the synthetic 1‐amino‐3‐iminopropene derivative of glycine as standard for quantitation of fluorescence, the molar ratios of oxygen absorbed per fluorescent compound produced were calculated. This ratio for subcellular particles isolated from rats fed diets with PUFA ratios similar to those in the average American human diet was 393∶1. The fluorescent compounds had the same spectral characteristics as the lipofuscin pigment that accumulates in animal tissues as a function of age, oxidative stress or antioxidant deficiency. The fluorescent molecular damage represented by that accumulated in human heart age pigment by 50 years of age was calculated to have been caused by approximately 0.6 μmole of free radicals per gram of heart tissue.
Net esterification in vitro of plasma cholesterol in human primary hyperlipidemia
Authors: Marcel Yves L. , Fabien Hélène D. , Davignon Jean
Published: November 2006

Net esterification of cholesterol was studied in vitro in the plasma of normal subjects and of patients with different types of hyperlipidemia. Net esterification of cholesterol was found to be significantly enhanced in types IIa, IV and V of human primary hyperlipidemia. In the plasma of all normal and hyperlipidemic subjects taken as a group, net esterification of cholesterol is significantly correlated with free cholesterol (p<0.001) and with phosphatidyl choline (p<0.001).
Mass spectrometric analysis of mono‐ and dialkyl ethers of diols
Authors: Kramer John K. G. , Holman Ralph T. , Baumann Wolfgang J.
Published: November 2006

Mass spectra of homologous series of long chain mono‐ and dialkyl ethers of ethanediol and propanediols were measured and general patterns of fragmentation were established. Both classes of diol lipids produce ions which are characteristic for the alkoxy moieties as well as ions which are typical of the constituent short chain diols. Prominent ions are formed by cleavages α and β to the ether oxygen and by rearrangement of one or two hydrogens and concurrent fission. High resolution mass spectrometry and deuterium labeling techniques were used to verify the composition of ions and to substantiate fragmentation mechanisms.
Synthesis of C‐18 mixed acid diacyl‐sn‐glycerol enantiomers
Authors: Buchnea Dmytro
Published: November 2006

Procedures have been developed for the synthesis of both enantiomeric forms of mixed fatty acid, saturated and polyunsaturated 1,2‐diacyl‐sn‐glycerols and 2,3‐diacyl‐sn‐glycerols from D‐mannitol as starting material. The following diacyl‐sn‐glycerols have been synthesized: 1‐Stearoyl‐2‐linoleoyl‐sn‐glycerol, 1‐stearoyl‐2‐linolenoyl‐sn‐glycerol, 2‐linoleoyl‐3‐stearoyl‐sn‐glycerol and 2‐linolenoyl‐3‐oleoyl‐sn‐glycerol. Their specific rotations, refractive indices, densities, solubilities, carbon and hydrogen analysis and iodine values have been reported.
Effects of pure oxygen atmosphere in vivo on plasma lecithin‐cholesterol acyltransferase reaction
Authors: Mikel Hubert S. , Foulds Emmet L. , Clark Dale A. , Larkin Edward C.
Published: November 2006

Exposure to pure oxygen atmospheres for more than three days resulted in loss of red blood cell mass in astronauts in some flights. Oxidation of lipid or protein membrane components may account for this phenomenon, since tocopherol deficient red blood cells have been shown to hemolyze on exposure to elevated oxygen pressures in vitro and in vivo. An additional contributing cause to the induced red cell loss may be the inhibition of the plasma lecithin‐cholesterol acyltransferase reaction by oxygen, since congenital absence of the enzyme is associated with anemia. This possibility was explored in eight human subjects who lived in a sealed environmental chamber and breathed 100% oxygen at 258 mm Hg pressure for 30 days. In their plasma a 40% decrease in the conversion of free cholesterol to ester was demonstrated in vitro after four weeks’ exposure to 100% oxygen. Plasma cholesteryl ester concentration was also decreased. Red blood cell mass was reduced and erythropoiesis was depressed. These findings support the hypothesis that the anemia induced by exposure to 100% oxygen was caused in part by decreased synthesis of cholesteryl esters secondary to an inhibition of the plasma lecithin‐cholesterol acyltransferase reaction.
Effects of renal factors on in vitro hepatic cholesterol synthesis in the rat
Authors: Haven Guy T. , Jacobi Herbert P.
Published: November 2006

Two products derived from rat renal tissue have been shown to affect in vitro hepatic cholesterol synthesis. A premevalonate inhibitor of hepatic cholesterol synthesis is associated with the membranes of the renal endoplasmic reticulum. It is stable at −75 C and at 4 C but is heat labile. A pre‐mevalonate stimulator of in vitro hepatic cholesterol synthesis is located within renal lysosomes and can be prepared in a nonsedimentable form by extraction with hypotonic buffer. While it is stable at −75 C, it loses activity at 4 C. Both of these products appear to have a molecular weight in excess of 150,000 as determined by gel filtration.
The structural analysis of wheat flour glycerolipids
Authors: Arunga R. O. , Morrison W. R.
Published: November 2006

The compositions of the fatty acids in the 1, 2 and 3 positions of the principal glycerolipids and their various stereoisomers were determined. Fatty acids in the 1 and 3 positions of triglycerides were similar in composition and less unsaturated than those in the 2 position. Fatty acids in the 1,2‐, 1,3‐ and 2,3‐diglycerides were distributed in a pattern which indicated isomerization ofsn‐1,2‐diacylglycerol. Lysophosphatidyl choline (the principal monoacyl lipid) consisted of about 80% 1‐acyl and 20% 2‐acyl isomers. The fatty acid compositions indicated that most of the 2‐lysophosphatidyl choline was formed by isomerization of 1‐lysophosphatidyl choline. Most of the digly cerides and lysophosphatidyl choline were synthesized in the ripening wheat grain. However a small proportion of these partial glycerides and all of the other minor partial glycerides (monoglycerides, digalactosyl monoglycerides) appeared to be the result of limited lipolysis of the corresponding diacyl lipids in the wheat or in the freshly‐milled flour. Fatty acids in the 2 position of all the fully acylated glycerides were very similar in composition, but there were considerable differences in the 1 position fatty acids.
Studies on the nuclear magnetic resonance spectra of olefinic protons of conjugated fatty acid methyl esters
Authors: Suzuki Osamu , Hashimoto Tetsutaro , Hayamizu Kikuko , Yamamoto Osamu
Published: November 2006

The NMR spectra of olefinic protons in the four representative conjugated fatty acid methyl esters, methylcis‐9,trans‐11‐octadecadienoate, methyltrans‐9,trans‐11‐octadecadienoate, methyl α eleostearate, and methyl β eleostearate, were studied. The chemical shift of each olefinic proton in these compounds was determined by considering their intramolecular environment. Coupling constants were also obtained as the results of spectral analysis.
Preparation of3H‐phosphatidylmyoinositol withKloeckera brevis
Authors: Prottey Colin , Seidman Michael M. , Ballou Clinton E.
Published: November 2006

The growth ofKloeckera brevis in the presence of uniformly tritiated myoinositol is described. The major radioactive lipid isolated from the cells is3H‐phosphatidylmyoinositol, labeled exclusively in the myoinositol moiety. Chromatographic methods for purifying3H‐phosphatidylmyoinositol, free from other labeled lipids, are described, and the use of this labeled lipid as a precursor in studying enzymatic synthesis of complex inositol lipids is demonstrated.
Liver lipids of the polar bear,Thalarctos maritimus
Authors: Gershbein Leon L. , Singh Eric J.
Published: November 2006

The distribution of total and free fatty acids as well as the acids from the glycerides, sterol esters and phospholipids of polar bear liver lipids was ascertained and found to contain somewhat higher levels of unsaturated components as compared to those of such mammals as the pig. Saponification of the liver lipids yielded the hydrocarbons, alcohols and sterols which were analyzed by GLC. The hydrocarbons occurred at an overall level of 55 mg/kg liver or 57.9 mg/100 g total lipids, of which pristane and other saturated hydrocarbons, mainly normal homologs, comprised 2.6 and 5.3 mg/100 g, respectively; the remainder contained squalene (37.7 mg/100 g) and other unsaturated types (12.3 mg/100 g). As based on the total lipids, the levels of fatty alcohols, sterol and glyceryl ethers amounted to 1.65%, 5.9% and 0.03%, respectively. The fatty alcohols displayed about 31 peaks of C12 to C30, of which the hexadecanol and a branched C20 component were prominent.
Chain length specificity of the saturated fatty acyl desaturase in rat liver preparations
Authors: Raju P. K. , Reiser Raymond
Published: November 2006

Chain length specificity of the saturated fatty acyl desaturase was studied in rat liver preparations using both de novo synthesized long chain fatty acids and equimolar mixtures of preformed fatty acids. Both experiments show that myristic acid is least desaturated and palmitic and stearic acids are desaturated in about equal amounts.
Lipolysis, esterification and glucose oxidation by human omental isolated adipose cells: The effects of pH, buffer and epinephrine
Authors: Ashley B. C. E. , Goldrick R. B.
Published: November 2006

The rates of glycerol productions, glucose oxidation and glucose conversion to glyceride‐glycerol by human omental fat cells were compared in vitro at pH's from 7.0 to 8.4, with and without epinephrine, and in both Krebs‐Ringer‐bicarbonate and‐phosphate buffers. Basal glycerol production was not significantly altered by changes in pH, and was similar in each buffer. Epinephrine markedly increased glycerol production at each pH in both buffers, but significantly more was produced at pH 8.4 than at pH 7.4. Basal glucose metabolism was not affected by pH or by the type of buffer. Epinephrine caused a small increase in glucose oxidation at each pH in bicarbonate buffer but only at pH 7.8 in phosphate buffer, and had no effect on glucose conversion to glyceride‐glycerol.
Isotope effects in the desaturation of stearic to oleic acid
Authors: Johnson A. R. , Gurr M. I.
Published: November 2006

Comparisons have been made of the rates of desaturation of stearic to oleic acid using a series of differently labeled forms of the substrate and two different methods of assay. The reaction has been measured either by analyzing the amount of labeled oleic acid produced, or by analyzing the amount of tritium released into water from [9,10‐3H2]‐labeled substrates. The rate of desaturation of [1‐14C] stearic acid has been compared with that of [threo‐9,10‐3H2] and [erythro‐9,10‐3H2] stearic acids in which about 99% of the label was at the 9 and 10 positions and in which most of the labeled molecular species contained two tritium atoms. A further series of [erythro‐9,10‐3H2] stearates was used in which there was a greater proportion of tritium at positions other than 9 and 10 or a greater proportion of species containing only one tritium atom, or both. In the tritium release assay the enzyme discriminated against the tritium substrates, the discrimination being greater witherythro‐ditritio‐compounds than with monotritio orthreo‐ditritio‐compounds. The isotope effect was also observed when [3H] stearoyl‐CoA thiol esters were the substrates, and when the source of the enzyme was the green algaChlorella vulgaris. Despite the isotope effect, the release of tritiated water can be used as an assay of desaturase activity. If the absolute value of enzymic activity is required, however, the location and stereochemistry of the tritium atoms should be known or the method standardized against [1‐14C] stearic acid.
Sterol metabolism: XII. 26‐hydroxycholesterol in commercial cholesterol
Authors: Van Lier Johan E. , Smith Leland L.
Published: November 2006

Commercial cholesterol of bovine brain and spinal cord origin has been care‐fully examined for its 24‐ and 26‐hydroxycholesterol content. By alternate adsorption chromatography and chromatography on Sephadex LH‐20 26‐hydroxycholesterol was isolated from this course in 15 μg/g amounts, whereas 24‐hydroxycholesterol was not observed.
Glycerides ofLimnanthes douglasii seed oil
Authors: Phillips Bruce E. , Smith C. R. , Tallent W. H.
Published: November 2006

Brockerhoff‐type procedures were used to determine the amounts of each acyl group at each glyceride position ofLimnanthes douglasii seed oil. During the course of the analyses, small quantities of three acids isomeric with those previously found in the oil were identified by their ozonolysis products and their gas‐liquid chromatographic (GLC) behavior. The newly discovered constituents of the oil were 3‐octadecenoic acid (0.1%), 5‐octadecenoic acid (0.9%) and 11‐eicosenoic acid (3%). The saturated acids and those with ω‐9‐unsaturation are esterified most often to β‐glyceride positions inLimnanthes seed, while the acids with Δ5‐unsaturation occur generally at the outer glyceride positions. Although the Δ5‐unsaturated acids as a group exhibited no obvious preference for one outer position over the other, individual acids were unequally distributed between the 1‐ and 3‐sn‐glycerol positions. The probabilities of occurrence of the various triglycerides were calculated from the stereospecific analysis data by assuming a 1‐random, 2‐random, 3‐random distribution of the acyl groups. The calculations are in agreement with the composition of the whole oil, as determined by GLC.
Functions of sterols in plants
Authors: Heftmann Erich
Published: November 2006

Sterols have at least three functions in animals: they may act as precursors of other steroids, as hormones and as membrane components. The author advances the hypothesis that sterols have similar functions in plants.
Potential function of cholesterol in blood coagulation: Amplification of phospholipid thromboplastic activity
Authors: Sorbye Oyvind , Phillips Fred C. , Lundberg W. O.
Published: November 2006

Recalcification tests have revealed a two‐ to threefold increase in the thromboplastic activity of recombined phospholipid fractions from chicken erythrocyte lipids on supplementation with the original concentration of cholesterol. An optimal four‐ to fivefold increase was obtained at higher levels. Cholesterol esters had no such effect and clotting times with Russell's viper venom were not similarly affected.
Gas chromatographic separation of linoleic acid hydroperoxides as trimethylsilyl ethers of methyl hydroxystearates
Authors: Eriksson C. E. , Leu Karin
Published: November 2006

The primary products, 9‐ and 13‐hydroperoxy‐octadecadienoic acids, from lipoxygenase catalyzed oxidation of linoleic acid, were converted into the trimethylsilyl ethers of methyl 9‐ and 13‐hydroxystearates which were completely separated by gas chromatography on an OV‐17 methyl silicone (50% phenyl groups), capillary column.
Inhibition of desaturation of stearic acid in livers of rats fed ethionine
Authors: Lyman R. L. , Fosmire M. A. , Giotas C. , Miljanich P.
Published: November 2006

The effect of ethionine on the conversion of stearic acid to oleic acid was studied. Rats were fed essential fatty acid (EFA) deficient diet for three weeks, after which time half the animals were fed 0.25% DL‐ethionine for nine additional days. Seventeen hours prior to killing, they were fed a slurry of the diet containing 18‐14C‐stearic acid. Liver triglycerides and phospholipids were extracted and separated and their fatty acid composition and the distribution of radioactivity between stearic and oleic acid was determined. In the tissues studied, oleic acid was maintained at control levels in ethionine‐fed rats, but eicosatrienoic acid was significantly depressed. Distribution of radioactivity and specific activity of oleic acid in the triglycerides and phospholipids were significantly reduced by the analogue. In vitro studies of desaturation and chain elongation reactions, with liver microsomes, using 18‐14C‐stearic and 1‐14C‐linoleic acids as substrates, showed that ethionine depressed the synthesis of oleic acid from stearic and γ‐linolenic from linoleic acid. Elongation of linoleic adie to a 20∶2 fatty acid was unaffected by ethionine. Therefore, the results showed that ethionine inhibited desaturation of stearic to oleic acid in vivo and in vitro and probably also impaired the desaturation of oleic to octadeca‐6, 9‐dienoic acid. Maintenance of control levels of oleic acid in the tissues of ethionine‐fed, EFA deficient rats suggested the presence of synthetic pathways for oleic acid other than via desaturation of stearic acid.
Fatty acid composition of the neutral lipids and individual phospholipids of muscle of cold‐stressed arctic mice
Authors: Eybel Carl E. , Simon R. Gerald
Published: November 2006

Fatty acids of the individual phospholipids and total neutral lipid fractions in skeletal muscle of three species of Arctic mice were identified and quantitated after the mice had been classified as control, cold‐sensitive or cold‐resistant. The results indicate that some species increase the percentage of unsaturated fatty acids as an apparent result of cold exposure and some species do not. A common finding for all cold‐sensitive mice was a significant increase in 14∶0 in phosphatidic acid when compared to cold‐resistant and control animals. Hypotheses are presented in an attempt to explain this finding.
Effect of culture temperature on fatty acid composition ofChlorella sorokiniana
Authors: Patterson Glenn W.
Published: November 2006

Chlorella sorokiniana was grown for extraction of fatty acids at seven temperatures ranging from 14 C to 38 C. The predominant fatty acids inC. sorokiniana grown at 38 C were saturated (46% of total); at 22 C, triunsaturated (40% of total); and at 14 C diunsaturated (47% of total). Increasing temperature resulted in an increase in the degree of unsaturation from 14 C to 22 C, but further increases in temperature always resulted in a decrease in unsaturation. At any point in the temperature range used, an increased temperature always resulted in fatty acids with a lower average chain length. Total fatty acid production was greatest at the extremes of temperature and lowest at 26 C. The chain length and degree of saturation of fatty acids increased at temperatures lower than 22 C. Therefore, the fatty acids ofC. sorokiniana do not have an increasingly lower melting point when the culture temperature is reduced at temperatures 22 C or below.
Desaturation of saturated fatty acids by rat liver microsomes
Authors: Paulsrud John R. , Stewart Sheila E. , Graff Gustav , Holman Ralph T.
Published: November 2006

A method was developed for the rapid determination of the initial velocity of the desaturation of saturated fatty acids. In the reaction, DPNH was a more efficient electron donor than TPNH. Fatdeficient rats have a 2.5‐fold greater level of acyl desaturase per milligram of liver microsomal protein than did animals fed lab chow. Increasing the chain length of the acyl substrate from 10∶0 to 18∶0 increases the rate of monoene formation, but 19∶0 is desaturated at a rate lower than that for 15∶0. The energy of activation (Ea) for the overall desaturation reaction has been determined for 12∶0 through 19∶0. The Ea values for desaturation of 13∶0 and 16∶0 are markedly lowr than for the other acids. An interaction between the alkyl chain of the substrate and polyunsaturated acids of the microsomal membrane‐bound phospholipids is postulated to explain the recurring 3‐carbon pattern of the relative reaction rates of the various acyl substrates.
The metabolism of linoleic and arachidonic acids in rat testis
Authors: Bridges Raymond B. , Coniglio John G.
Published: November 2006

Linoleic and arachidonic acids, labeled with14C and injected intratesticularly, were used to study with time the interconversion of polyunsaturated fatty acids in rat testis and their incorporation into the major lipid classes. With both substrates14C activity was readily incorporated into longer chain, more highly unsaturated fatty acids. After the injection of 1‐14C‐linoleic acid the major portion of the14C was found in palmitic, linoleic, 8,11,14‐eicosatrienoic, 5,8,11,14‐eicosatetraenoic, 7,10,13,16‐docosatetraenoic and 4,7,10,13,16‐docosapentaenoic acids. Hydrogenation of the total fatty acids isolated from rat testes after intratesticular injection of 1‐14C‐linoleate revealed that the polyenoic acids hydrogenating to lignoceric acid (previously characterized as 9,12,15,18‐tetracosatetraenoate and 6,9,12,15,18‐tetracosapentaenoate) had a relatively high specific activity. After the injection of 1‐14C‐arachidonate significant14C activity was found in palmitate, 7,10,13,16‐docosatetraenoate, 4,7,10,13,16‐docosapentaenoate, 9,12,15,18‐tetracosatetraenoate and 6,9,12,15,18‐tetracosapentaenoate. The biosynthesis of the ω6 polyunsaturated fatty acids in rat testis is discussed in relation to these data. Investigation of the distribution of label in the complex lipid fractions demonstrated the majority of the14C activity to be present in phosphatides and triglycerides after injection of either of these14C substrates with only small quantities being present as nonesterified acids. At the time periods studied the polyenoic acids of triglycerides had a higher specific activity than the corresponding acids of phosphatides with the exception of linoleate.