bluuebunny/crossref_metadata_2025 huggingface dataset:
Lipid composition of the membrane released after an in vitro acrosome reaction of epididymal boar sperm
Authors: Nikolopoulou Maria , Soucek Donald A. , Vary James C.
Published: November 2006

Prior to fertilization, mammalian sperm must undergo the acrosome reaction, which involves modifications of the plasma and outer acrosomal membranes followed by vesiculation and release of the membranes. The membrane fraction that was released from caudal boar sperm undergoing an in vitro acrosome‐like reaction was isolated and characterized with respect to density, marker enzymes and lipid composition. This membrane had a lower phospholipid/protein ratio (mg/mg) than the sperm plasma membrane, whereas both membranes had similar molar sterol/phospholipid ratios. The major phospholipid was sphingomyelin, followed by phosphatidylethanolamine and phosphatidylcholine, whereas in the plasma membrane the order was reversed; the two major phosphoglycerides contained alkylacyl and alkenylacyl species in addition to the diacyl species. The released membrane also contained lower amounts of cholesterol sulfate and unsaturated fatty acids than the plasma membranes. These results, in combination with our studies on the changes of the sperm membranes during maturation and acrosome reaction, will allow a better understanding of the mechanism of the sperm acrosome reaction.
Fast atom bombardment and tandem mass spectrometry of phosphatidylserine and phosphatidylcholine
Authors: Jensen Nancy J. , Tomer Kenneth B. , Gross Michael L.
Published: November 2006

Fast atom bombardment (FAB) desorption of phosphatidylserine and various phosphatidylcholines produces a limited number of very informative negative ions. Especially significant is the formation of (M‐H)− ions for phosphatidylserine, a compound which does not yield informative high mass ions by other ionization methods. Phosphatidylcholines of not yield (M‐H)− ions but instead produce three characteristic high mass ions, (M‐CH3+_−, [M‐HN(CH3)3+]− and [M‐HN(CH33+‐C2H2]−. Both classes of lipids also yield anions attributed to the carboxylate components of these complex lipids. FAB desorption in combination with collisional activation allows for characterization of fragmentation and determination of structural features. Collisional activation of the carboxylate anion fragments from the complex lipids is especially informative. Structural characterization of the fatty acid chain can be achieved as the released saturated carboxylate anions undergo a highly specific 1,4‐elimination of H2, which results in the losses of the elements of CH4, C2H6, C3H8...in a fashion entirely consistent with the chemistry of carboxylate anions desorbed from free fatty acids. These CnH2n+2 losses begin at the alkyl terminus and progress along the entire alkyl chain. Modified fatty acids undergo a similar fragmentation; however, the modification affects the series of CnH2n+2 losses in a manner which permits determining the type of modification and its location on the fatty acid chain.
A relationship between essential fatty acid and vitamin E deficiency
Authors: Subramanian Carole S. , Mead James F.
Published: November 2006

To test whether vitamin E deficiency might influence the course of essential fatty acid (EFA) deficiency, Long Evans rats were fed diets containing a marginal amount (1.5% of calories) of 18∶2ω6 or 18∶3ω3 fatty acid with complete absence of the other and with or without vitamin E. Vitamin E contents decreased continuously in serum and liver in all rats fed the E‐free diets but in the brains of only the rats fed the marginal 18∶3ω3, E‐free diet. It is considered that the vitamin E is cooxidized in the liver with 22∶6ω3, since this fatty acid is very low in livers of the rats fed the marginal 18∶2ω6 diet but much higher in livers of the rats fed the marginal 18∶3ω3 diet. Brain 22∶6ω3 values are comparable for both groups. The source of 22∶6ω3 is evidently in the mother's milk, since following weaning there is a precipitous drop in 22∶6ω3 in serum, liver and carcass of rats on the 18∶2ω6‐containing diet. No significant signs of EFA deficiency were seen in the E‐deficient rats.
Imprints of virus infection: Can paramyxoviruses permanently modify triacylglycerol metabolism?
Authors: Wild T. F. , Bernard A. , Malak N. Abdul , Brichon G. , Zwinglestein G.
Published: November 2006

We have examined whether the passage of a paramyxovirus in a cell (BGM, African green monkey kidney) or animal (Swiss mouse) can permanently modify its metabolism. In an in vitro model in which cells had been cured of a measles virus persistent infection, the cells retained the modifications affecting lipid metabolism and composition induced during the infection. In a canine distemper virus mouse model, the same virus‐induced modifications were observed in mice after the virus had been eliminated.
Metabolism of erucic acid in perfused rat liver: Increased chain shortening after feeding partially hydrogenated marine oil and rapeseed oil
Authors: Christiansen E. N. , Thomassen M. S. , Christiansen R. Z. , Osmundsen H. , Norum K. R.
Published: November 2006

The metabolism of [14‐14C] erucic acid was studied in perfused livers from rats fed on diets containing partially hydrogenated marine oil or rapeseed oil for three days or three weeks. Control rats were given groundnut oil. Chain‐shortening of erucic acid, mainly to 18∶1, was found in all dietary groups. In the marine oil and rapeseed oil groups, the percentage of chain‐shortened fatty acids in very low density lipoproteins‐triacylglycerols (VLDL‐TG) exported from the liver increased after prolonged feeding. A similar increase was found in liver TG only with partially hydrogenated marine oil. This oil, rich intrans fatty acids, thus seemed to be more effective in promoting chain‐shortening. The fatty acid composition of the secreted and stored TG differed both with respect to total fatty acids and radioactively labeled fatty acids, indicating that at least 2 different pools of TG exist in the liver. The lack of lipidosis in livers from rats fed dietary oils rich in 22∶1 fatty acids is discussed in relation to these findings. In conclusion, a discussion is presented expressing the view that the reversal of the acute lipidosis in the hearts of rats fed rapeseed oil or partially hydrogenated marine oils is, to a large extent, derived from the increased chain‐shortening capacity of erucic acid in liver.
Fatty acid composition of heart cells exposed to thermally oxidized fats
Authors: Bird R. P. , Alexander J. C.
Published: November 2006

Corn oil and olive oil were thermally oxidized, and the free fatty acids from the fresh fats, and from the distillable non‐urea‐adductable (DNUA) fractions of the thermally oxidized fats were prepared. These were added as emulsions to the medium of primary cultures of heart endothelial and muscle cells from neonatal rats. After exposure for 24 hr, the fatty acid composition of the triacylglycerol (TC) and phospholipid (PL) fractions of the cells was determined. Reflecting the nature of the fat used, the corn oil treatment produced relatively higher concentrations of linoleic acid in the TG and PL fractions compared to the olive oil treatment, in which case the oleic acid level was influenced. Treatment of the cultured cells with components derived from oxidized corn oil or oxidized olive oil resulted in lower concentrations of linoleic and arachidonic acids in the PL moieties compared to the fresh fat controls. However, there were marked increases in arachidonic acid in the TG fractions of both the endothelial and muscle cells. These changes due to the DNUA from thermally oxidized fats indicate a distinct metabolic response to the derivatives formed during thermal oxidation of the fats.
Oxidation of 3‐oxygenated Δ4‐ and Δ5‐C27 steroids by soybean lipoxygenase and rat liver microsomessteroids by soybean lipoxygenase and rat liver microsomes
Authors: Aringer Leif
Published: November 2006

The formation of dioxygenated metabolites of cholesterol, epicholesterol (5‐cholesten‐3α‐ol) 4‐cholesten‐3β‐ol, 4‐cholesten‐3α‐ol, 4‐cholesten‐3‐one and 4‐stigmasten‐3‐one was studied after incubations with soybean lipoxygenase and linoleic acid. From cholesterol and epicholesterol were formed the 7α‐hydroxy‐, 7α‐hydroperoxy‐, 7β‐hydroxy‐, 7β‐hydroperoxy‐, 7‐oxo and 5,6‐epoxyderivatives as well as 6β‐hydroxy‐4‐cholesten‐3‐one. All Δ4‐steroids were hydroxylated in the 6α‐ and 6β‐positions. The ratios between the yields of 6β‐ and 6α‐hydroxylated metabolites varied between 3∶1 and 2∶1. Incubations with 4‐cholesten‐3α‐ol and 4‐cholesten‐3β‐ol also afforded the 4,5‐epoxides of these steroids. The ratios between the yields of the 4β,5β‐ and 4α,5α‐epoxides were ca. 4∶1 for 4‐cholesten 3β‐ol and ca. 3∶2 for 4‐cholesten‐3α‐ol. With iron‐supplemented microsomes from rat liver, the compounds formed were qualitatively and quantitatively the same as with soybean lipoxygenase, whereas with 18,000 × g rat liver supernatant fractions the yields of all products formed—except 7α‐hydroxycholesterol and 6β‐hydroxy‐4‐cholesten‐3‐one—were markedly decreased. The results indicate the presence of a rat liver microsomal 6β‐hydroxylase which can use 4‐cholesten‐3‐one as a substrate and extend previous findings of similarities between soybean lipoxygenase and a nonspecific lipoxygenase in rat liver microsomes.
Cuticular lipid constituents of cabbage seedpod weevils and host plant oviposition sites as potential pheromones
Authors: Richter Ingolf , Krain Horst
Published: November 2006

The cuticular lipids of cabbage seedpod weevils (Ceutorrhynchus assimilis Payk.) and those at their oviposition site, i.e., the seed pods of the host plant (Brassica napus L.), were analyzed by chromatographic techniques in conjunction with mass spectrometry (MS). Long chain hydrocarbons were most abundant in both lipids; however, the seed pods ofB. napus containedn‐alkanes only, whereasC. assimilis showed a predominance of dimethylalkanes over internally branched methylalkanes as well as iso‐ andn‐alkanes. The amounts of ketones, secondary alcohols and aldehydes, the usual plant components that are unique in insects, occurred in cuticular lipids of both organisms in approximately the same ratio. The composition ofn‐alkanes,n‐ketones, secondaryn‐alcohols, iso‐ and anteisoaldehydes and esterified primary anteiso‐alcohols of wax esters was similar betweenC. assimilis andB. napus. In both sources, qualitative but not quantitative similarities were observed in the composition ofn‐aldehydes and esterified primaryn‐ and iso‐alcohols, respectively. The esterified fatty acids of wax esters fromB. napus were composed of roughly equal proportions of saturated branched and unbranched components. The esterified fatty acids of wax esters and steryl esters fromC. assimilis consisted of major proportions of saturated as well as unsaturatedn‐compounds, whereas iso‐ and anteiso structures were present in minor proportions only. Free fatty acids and traces of ethyl esters of fatty acids found inC. assimilis were mainly composed of unsaturatedn‐compounds.
Free fatty acid content of human milk: Physiologic significance and artifactual determinants
Authors: Chappell Janet E. , Clandinin Michael T. , McVey Muriel A. , Chance Graham W.
Published: November 2006

Analysis of human milk was conducted to determine if free fatty acids occur naturally or as a consequence of artifactual lipolysis after milk expression. Five mothers provided triplicate early morning milk samples on day 43 of lactation. Following extraction, lipid classes were separated by preparative thin layer chromatography and quantified by capillary gas liquid chromatography. Fresh milk samples collected with 20 volumes chloroform‐methanol (1∶1, v/v) were analogous in total free fatty acid level and profile of fatty acids to a duplicate sample collected with 0.4M EDTA and immediately frozen at −10 C. Low milk levels of free fatty acids appear to exist naturally. During days 4–37 of lactation, four serial milk samples from 15 mothers were collected and frozen with 0.4M EDTA. The concentration of free fatty acids in colostrum (0.03–0.5%, w/w) was lower than for subsequent days (0.3–2.5%, w/w). Additional samples were collected with and without a lipase inhibitor (0.4M EDTA) and subjected to routine collection and storage procedures. Significantly different fatty acid profile and higher levels of free fatty acids in milk collected without a lipase inhibitor added indicate that domestic freezing and/or thawing ruptures the fat globule membrane, allowing sn‐1‐stereospecific serum stimulated lipoprotein lipase contact with its triglyceride substrate. Standard procedures for collection of human milk for gavage fed infants appear to stimulate artifactual lipolysis of milk triglyceride and subsequent release of free fatty acids. The proposed relationship between dietary free fatty acids and prolonged, unconjugated hyperbilirubinemia in the newborn is discussed with regard to the significance of preintestinal lipolysis.
The squalene‐2,3‐epoxide cyclase as a model for the development of new drugs
Authors: Cattel L. , Ceruti M. , Viola F. , Delprino L. , Balliano G. , Duriatti A. , Bouvier‐Navé P.
Published: November 2006

The 2,3‐oxido squalene (SO) cyclases represent a group of enzymes which convert SO into polycyclic triterpenoids such as lanosterol, cycloartenol, cucurbitadienol and β‐amyrin. Taking into account the postulated model of the enzymatic cyclization of SO, we have investigated the possibility of designing compounds that would be selective and potent inhibitors of SO cyclases. Due to the fundamental role of sterols in animal, higher plant and fungal tissues, these inhibitors might behave as very selective (ipocholesterolemic, antifungal or phytotoxic) drugs.

Our first approach was the synthesis and biological evaluation of 2‐aza‐2,3‐dihydrosqualene and its derivatives which, being protonated at physiological pH, would present some similarities to the C‐2 carbon ion generated by the opening of the oxirane ring of SO. Microsomes from different sources (germinated pea cotyledons, maize seedlings, rat liver and yeasts) were utilized to determine the inhibition values (I50: concentration of inhibitor producing 50% inhibition at a given substrate concentration).

From the results obtained so far we conclude that 2‐aza‐2‐dihydrosqualene and its derivatives strongly inhibited the cyclases, the site of the enzyme responsible for binding to the inhibitor is quite sensitive to the steric hindrance, and the degree of the inhibitory activity is greater in higher plants than in rat liver or fungi.
Sterols of cucurbitaceae: The configurations at C‐24 of 24‐Alkyl‐Δ5‐,Δ7‐ and Δ8‐sterols
Authors: Akihisa Toshihiro , Thakur Swapnadip , Rosenstein Fumiko U. , Matsumoto Taro
Published: November 2006

The major sterols of the seeds ofBenincasa cerifera, Cucumis sativus, Cucurbita maxima, C. pepo andTrichosanthes japonica and of the mature plant tissues (leaves and stems) ofCitrullus battich, Cucumis sativus andGynostemma pentaphyllum of the family Cucurbitaceae were 24‐ethyl‐Δ7‐sterols which were accompanied by small amounts of saturated and Δ5‐and Δ8‐sterols. The 24‐ethyl‐Δ7,22,Δ7,25(27) and Δ7,22,25(27)‐sterols constituted the predominant sterols for the seed materials, whereas the 24‐ethyl‐Δ7 and Δ7,22‐sterols were the major ones for the mature plant tissues. The configurations of C‐24 of the alkylsterols were examined by high resolution1H NMR and13C NMR spectroscopy. Most of the 24‐methyl‐ and 24‐ethylsterols examined which lack a Δ25(27)‐bond (i.e., 24‐methyl‐, 24‐methyl‐Δ22‐, 24‐ethyl‐ and 24‐ethyl‐Δ22 sterols) were shown to occur as the C‐24 epimeric mixtures in which the 24α‐epimers predominated in most cases. The 24‐ethylsterols which possess a Δ25(27) (i.e., 24‐ethyl‐Δ25(27)‐and 24‐ethyl‐Δ7,22,25(27)‐sterols) were, on the other hand, composed of only 24β‐epimers. The Δ8‐sterols identified and characterized were four 24‐ethyl‐sterols: 24α‐and 24β‐ethyl‐5α‐cholesta‐8,22‐dien‐3β‐ol, 24β‐ethyl‐5α‐cholesta‐8,25(27)‐dien‐3β‐ol and 24β‐ethyl‐5α‐cholesta‐8,22,25(27)‐trien‐3β‐ol. This seems to be the first case of the detection of Δ8‐sterols lacking a 4‐methyl group in higher plants, and among the four Δ8‐sterols the latter two are considered to be new sterols. The probable biogenetic role of the Δ8‐sterols and the possible biosynthetic pathways leading to the 24α‐ and 24β‐alkylsterols in Cucurbitaceae are discussed.
Biosynthesis of 24‐methylcholest‐5‐en‐3β‐ol and 24‐ethylcholest‐5‐en‐3β‐ol inZea mays
Authors: Rendeli Nigel , Misso Neil L. A. , Goad L. John
Published: November 2006

The relative rates of synthesis of 24‐methylcholest‐5‐en‐3β‐ol and 24‐ethylcholest‐5‐en‐3β‐ol inZea mays shoots were determined using [2‐14C]mevalonic acid and [methyl‐14C]methionine as substrates. The 24‐ethylsterol had a higher specific activity and it apparently was synthesized at about 3–4 times the rate of the 24‐methylsterol.1H NMR spectroscopy showed that the 24‐ethylsterol was predominantly the 24α‐epimer but the 24‐methylsterol was a mixture of the 24α‐epimer (30–40%) and the 24β‐epimer (60–70%). The results are discussed in relation to the involvement of Δ24(28)‐, Δ23, Δ25‐ and Δ24(25)‐sterol intermediates in 24‐methyl‐ and 24‐ethylsterol production.
Selective sterol transfer in the honey bee: Its significance and relationship to other hymenoptera
Authors: Svoboda James A. , Herbert Elton W. , Thompson Malcolm J. , Feldlaufer Mark F.
Published: November 2006

The honey bee,Apis mellifera, is one of only a few species of phytophagous insects known to be unable to convert C‐24 alkyl phytosterols to cholesterol. Regardless of the dietary sterols available to worker bees, the major tissue sterol of brood reared by the workers is always 24‐methylenecholesterol, followed by sitosterol and isofucosterol. Normally, little or no cholesterol is present in honey bee sterols. The maintenance of high levels of certain sterols is accomplished through a selective transfer of sterols from the endogenous sterol pools of the workers to the developing larvae through the brood food material secreted from the hypopharyngeal and mandibular glands and/or the honey stomach of the workers. The selective uptake and transfer of radiolabeled C27, C28 and C29 sterols have been studied to correlate these aspects of sterol utilization with the discovery of an unusual molting hormone (ecdysteroid) in honey bee pupae as the major ecdysteroid of this stage of development. The phylogenetic implications of this selective transfer phenomenon in the honey bee and comparison with sterol metabolism in certain other hymenopteran species emphasize the diversity of steroid biochemistry in insects.
Evidence for facilitated transport in the absorption of sterols bySaccharomyces cerevisiae
Authors: Nes William R. , Dhanuka Inder C. , Pinto William J.
Published: November 2006

Saccharomyces cerevisiae is known to absorb sterols readily in the absence of air. As shown in this paper yeast cells also will absorb sterols with and without various double bonds or an alkyl group at C‐24 in the presence of air at a concentration (ca. 10% of the gas phase) which is growth‐limiting due to limited sterol synthesis. However, if the growth conditions are changed to be fully aerobic, sterol is no longer absorbed to any significant extent even when the sterol in the medium (ergosterol) is the same as that present in the cells. This implies that sterol in the medium does not equilibrate passively with sterol in the plasma membrane and that some sort of facilitated transport, which can be turned on and off, is responsible for the entry of sterol when it occurs as a response to an inadequate endogenous supply of sterol. In agreement with facilitated transport mediated by protein binding, yeast cells in an auxotrophic state for sterol exhibit a high degree of stereoselectivity with respect to the orientation of the side chain around the C‐17(20)‐bond. For instance, E‐17(20)‐ but not Z‐17(20)‐dehydrocholesterol is absorbed by cells undergoing limited growth with 10% air.
Sterols of the oyster,Crassostrea virginica
Authors: Teshima Shin‐Ichi , Patterson Glenn W. , Dutky Samson R.
Published: November 2006

A commericial sample of the oyster,Crassostrea virginica, obtained from Maryland waters of the Chesapeake Bay, contained 31 desmethylesterols and at least eight 4‐monomethylsterols. The combined gas liquid chromatography‐mass spectra of the minor components showed the presence of 6 unusual sterols, 24‐ethylcholest‐22‐en‐3β ol, 4α‐methyl‐24‐ethylcholestan‐3β‐ol, occelasterol, (24E)‐24‐propylidene‐cholest‐5‐en‐3β‐ol, (24ZO‐24‐propylidene‐cholest‐5‐en‐3β‐ol, and 24‐methylene‐cholestanol. The C‐24 configuration of 24‐ethylcholest‐5‐enol, 24‐methyl‐cholesta‐5,22‐dienol, and 24‐ethylcholesta‐5,22 dienol were elucidated by 220 MHz nuclear magnetic resonance spectrometry.
Dietary fibers: V. Binding of bile salts, phospholipids and cholesterol from mixed micelles by bile acid sequestrants and dietary fibers
Authors: Vahouny George V. , Tombes Robert , Cassidy Marie M. , Kritchevsky David , Gallo Linda L.
Published: November 2006

Mixed micelles were prepared containing combinations of either taurocholate or taurochenodeoxycholate, monoolein, oleic acid, dioleylphosphatidylcholine (lecithin) and cholesterol. These were incubated with commercial bile‐acid‐sequestering resins, cholestyramine and DEAE‐Sephadex, or various dietary fibers and fiber components including wheat bran, cellulose, alfalfa, lignin and 2 viscosity grades of guar gum. Binding was determined as the difference between the radioactivity of each micellar component added and that recovered in the centrifugal supernatant after incubation. In general, the extent of bile salt sequestration was characteristic and reproducible for each bile salt, and was largely unaffected by the presence of one or more additional components of the micellar mixture, including the other bile salt. Cholestyramine bound 81–92% of the bile salts and 86–99% of the phospholipid and cholesterol present in micelles. DEAE‐Sephadex sequestered only 49% of the taurocholate and 84% of the taurochenodeoxycholate, but completely removed all of the phospholipid and cholesterol from micelles containing either bile salt. Among the dietary fibers, guar gum of either viscosity bound between 20–38% of each micellar component, whereas lignin, alfalfa, wheat bran and cellulose were progressively less effective in sequestratin of individual components of mixed micelles. The extent of sequestration of micellar components by these resins and fibers is reasonably correlated with the effects of these same materials on lymphatic absorption of lipids and to their suggested hypocholesteremic properties.
Dynamic lipid changes in rapidly proliferating hepatic smooth endoplasmic reticulum during acute dexamethasone treatment of adrenalectomized rats
Authors: Holloway Caroline Tobia , Margolis Ronald N.
Published: November 2006

The regulation by the cell of subcellular membrane components is dependent on a highly complex balance of nutritional, hormonal and metabolic events. We have characterized the lipid components of the endoplasmic reticulum (ER) of the liver of adrenalectomized (ADX) rats and the response of these membrane components to glucocorticoid administration. Membrane microviscosity as measured by fluorescence depolarization of 1,6‐diphenylhexatriene (DPH) was measured and correlated with lipid composition and content of the membranes. In the ADX rat, a significant increase in membrane microviscosity of the smooth endoplasmic reticulum (SER) was observed and this was accompanied by an increase in the cholesterol content/mg protein and a decrease in the phospholipid content/mg protein. A change in the fatty acyl chain composition is observed with a significant increase in the mole percentage of arachidonic acid (20∶4) and an accompanying decrease in saturated fatty acids. Within 2–6 hr of dexamethasone administration, a decrease in membrane microviscosity is observed that returns this value to one similar to that for normal control animals. Both the cholesterol and the phospholipid contents/mg protein are likewise restored to levels similar to that for control animals beginning at the 2‐hr time point. The arachidonic acid and saturated fatty acid content of the constituent phospholipids do not begin to return to values similar to those for control animals until 6 hr after dexamethasone administration. From these experiments, we can conclude that glucocorticoids play a significant regulatory role in determining the lipid properties of rat hepatic microsomal membranes.
Detection of hydroxy fatty acids in biological samples using capillary gas chromatography in combination with positive and negative chemical ionization mass spectrometry
Authors: Stan H. ‐J. , Scheutwinkel‐Reich M.
Published: November 2006

The most common method for use in the structural analysis of hydroxy fatty acids in biological samples is the gas chromatography‐mass spectrometry (GC‐MS) analysis of trimethylsilyl ethers of the methyl esters using electron impact ionization. A comparison of electron impact (EI) with chemical ionization mass spectrometry (CI‐MS) shows that CI‐MS is the superior technique. All ions necessary for structural analysis are observed at sufficiently high levels of intensity when methane or isobutane are used as reactant gases. The molecular weight can be determined from the ion group M+H, M‐15 and M+H−90. The ionic series M+H−n×90 enables one to determine the number of hydroxyl groups. The position of the hydroxyl groups can be derived from the fragments of the α‐cleavage of the fatty acid chain. The application of heptafluorobutyrates as derivatives for hydroxy fatty acid methyl esters shows advantages in the trace analysis of these compounds. Heptafluorobutyrates exhibit useful mass fragmentation patterns in the positive as well as in the negative CI mode. With methane as the reactant gas, M+H usually is base peak in positive mass spectra. The ionic series M+H−n×214 leads to the number of hydroxy groups in the molecule. In the negative mass spectra, M and M‐20 are indicative for the molecular weight. The ion group m/z 213, 194 and 178 at high levels of intensity is typical for heptafluorobutyrates. The advantage of the application of heptafluorobutyrates is the high sensitivity which can be obtained in trace analysis using negative MS. Heptafluorobutyrates of hydroxy fatty acids gave a 20‐fold higher response in the negative scan mode compared to that of the positive. The detection limit for heptafluorobutyrates in negative CI‐MS was on the order of 1 fg (10−15 g).
Occurrence of squalene in skin surface lipids of the otter, the beaver and the kinkajou
Authors: Lindholm Jane S. , Downing Donald T.
Published: November 2006

In a previous survey of the skin surface lipids of 46 mammalian species, it was found that only 3, the otter, the beaver and the kinkajou, contained components with chromatographic mobility similar to squalene, and in each case, this material was the predominant constituent. The materials in question have now been isolated from each of these species and identified as squalene by thin layer chromatography, gas chromatography and infrared spectroscopy. The occurrence of squalene in the surface lipids of these particular species cannot be explained on the basis of either their evolutionary relationship or ecological niche.
The interaction of human plasma low density lipoproteins with glycosamino‐glycans: Influence of the chemical composition
Authors: Kostner Gerhard M. , Zechner Rudolf , Bihari‐Varga Magdolna , Gruber E.
Published: November 2006

Human plasma of 5 normolipemic individuals was incubated for 24 hr at 37 C in the presence or in the absence of lecithin: cholesterol acyltransferase (LCAT)‐inhibitors. Plasma steored at 4 C served as a control. The low density lipoprotein (LDL) fractions of the samples were isolated and investigated with respected to changes in chemical composition and complexing activity with glycosamino glycans (GAG).

Incubation of plasma in the presence of LCAT inhibitors caused a significant increase of LDL triglycerides at the expense of cholesteryl esters. Incubation with active LCAT not only changed the core but also the surface constituents (decrease in phospholipids and in free cholesterol).

The amount of GAG bound per mg of LDL was not uniformly changed in samples incubated after LCAT inhibition. LDL isolated from plasma incubated in the presence of LCAT, on the other hand, showed a significant reduction in GAG binding.

The ratio of free cholesterol: GAG in the complex was most significantly reduced in LCAT‐modified LDL. There was in addition a highly significant correlation between the LDL:GAG ratio in the complex and the free cholesterol and phospholipid content of the LDL samples.

It is concluded that alterations in surface lipid constitutents of LDL strongly after their interaction with sulfated polysaccharides, an effect which may be relevant also in vivo for the interaction of LDL with cell surfaces and intercellular matrices.
A diurnal variation of hepatic acid cholesteryl ester hydrolase activity in the rat
Authors: Tanaka Mitsuo , Yonekura Ryooji , Iio Toshihiro , Tabata Toshikazu
Published: November 2006

The diurnal variation in lysosomal acid cholesteryl ester hydrolase (Acid CEH), (EC 3.1.1.13) has been examined in fed, fasted and adrenalectomized rats. The Acid CEH activity of normal rat liver exhibits a diurnal rhythm with maxima at 06.00 hours and minima at 18.00 hours, but such a rhythm was not observed in spleen and brain. This rhythm was abolished after fasting for two days, and the resulting Acid CEH activity remained constant at the minimum level. However, adrenalectomy did not abolish the diurnal rhythm. These results indicate that the Acid CEH activity varies according to a diurnal rhythm with maxima and minima separated by approximately 12 hr. Further, it is evident that the appearance of this rhythm is dependent upon dietary, but not adrenal hormone influence.
Cardiac lipid changes in rats fed oils enriched in saturates and their apparent relationship to focal heart lesions
Authors: Kramer J. K. G. , Farnworth E. R. , Thompson B. K.
Published: November 2006

Weanling male Spraque‐Dawley rats were fed diets containing 20% by weight corn, soybean or low erucic acid rapeseed oils or mixtures of the latter two with cocoa butter or triolein for 1, 2, 3 or 4 weeks. These diets previously had been fed to the same strain of rats for 16 weeks, and a reduction in the incidence of focal heart lesions had been observed with the addition of cocoa butter, but not triolein. The cardiac lipid classes and the fatty acid and alkenyl ethers of the cardiac phospholipids were analyzed to determine if changes could be attributed to the observed cardiopathological response, and at what time. Cardiac lipid classes changed during post‐weaning development, but only triacylglycerol was diet‐related. A number of fatty acid changes were observed in the cardiac phospholipids which reflected the relative concentration of saturates, monounsaturates, linoleic acid and linolenic acid in the diet, but only the changes in saturates and the C22 polyunsaturated fatty acids from the linolenic acid family appeared to be related to the incidence of focal heart lesions. Arachidonic acid and the total C22 polyunsaturated fatty acids remained fairly constant throughout the feeding trial. Cardiac diphosphatidylglycerol was least affected by dietary manipulation, while nervonic acid increased in cardiac sphingomyelin when small amounts of erucic acid were present in the diet. Fatty acid changes were essentially completed after one week on the experimental diets, whereas changes in the alkenyl ethers took two to three weeks.
Mass spectra of pyrrolidides of oxy, hydroxy and trimethylsilyloxy octadecanoic acids
Authors: Tulloch A. P.
Published: November 2006

Pyrrolidides of 16 isomeric oxooctadecanoic acids and 17 isomeric hydroxyoctadecanoic acids and their trimethylsily (TMS) ethers have been prepared and their mass spectra measured. Comparison of spectra of all the isomers has shown the variation in amide‐ and substituent‐directed fragmentation with position of the substitutent on the 18 carbon chain. Five diagnostic ions are present in spectra of most oxo pyrrolidides, and the most important one is formed by cleavage between the carbons α and β to the oxo group on the amide side. Mass spectra of hydroxy pyrrolidides have four diagnostic ions; the principal one in most spectra is formed by α‐cleavage at the oxygenated carbon on the terminal methyl side. There are four characteristic ions in spectra of the trimethylsiloxy pyrrolidides, and the two formed by α‐cleavage on one or the other side of the oxygenated carbon are the most important. Spectra of the 2‐, 3‐ and 4‐substituted isomers are considerably different from those of the other isomers. Mass spectra of pyrrolidides of three specifically deuterated oxo acids and of eight deuterated hydroxy acids and their trimethylsilyl ethers also were recorded and used to confirm the mode of formation of almost all the ions in the spectra. Two unusual hydrogen migrations, from the carbon α to the oxygenated carbon on the terminal methyl side, are involved in fragmentation of the trimethylsilyl ethers. Spectra have been compared with those of the corresponding oxygenated methyl esters.
Chylomicron remnant and asialoglycoprotein metabolism are independent
Authors: Cooper Allen D. , Coleman David
Published: November 2006

Because of the considerable similarities between the hepatic metabolism of chylomicron remnants and asialoglycoproteins, the hypothesis that they might share a cell surface receptor or a common step in internalization was tested. Unlabeled chylomicron remnants did not reduce the binding of125I‐asiaglycoprotein to plasma membranes, but did compete for125I‐chylomicron remanant binding. The converse also was true. This suggested the receptors were distinct. The two substances did not compete with each other for removal by the isolated perfused rat liver. This suggests that no potentially common post binding events can become rate limiting.

In conclusion, despite similarities in their removal and metabolism, chylomicron remnants and asialoglycoproteins are metabolized independently.
Free, esterified and glucosidic sterols in cocoa butter
Authors: Staphylakis K. , Gegiou D.
Published: November 2006

Sterol lipids of cocoa butter (cocoa beansLome Tongo) were fractionated into free sterols, steryl esters (SE), steryl glucosides and acylated steryl glucosides (ASG). 4‐Desmethyl, 4‐methyl and 4,4′‐dimethyl sterols or triterpene alcohols, which were isolated as free sterols or which resulted from hydrolysis, were determined by thin layer chromatography‐flame ionization detection and identified by gas chromatography and combined gas chromatography‐mass spectroscopy. Free sterols comprise the main sterol fraction in cocoa butter. Esterified sterols amount to 11.5% of total sterols and glucosidic sterols to 16.3%. Fatty acids and D‐glucose from hydrolysis of esters and glucosides were analyzed. The fatty acids of SE and ASG are richer in unsaturated fatty acids than cocoa butter total fatty acids.
Hydrolysis of intralipid by pancreatic lipase and phospholipase A2‐gel filtration studies
Authors: Grataroli Renée , Charbonnier Monique , Nalbone Gilles , Lairon Denis , Chabert Christiane , Hauton Jacques C. , Lafont Huguette
Published: November 2006

Intralipid was incubated with pancreatic lipase (EC 3.1.1.3) and/or phospholipase A2 (EC 3.1.1.4) at two bile salts/phosphatidylcholine molar ratios and at two different triglyceride hydrolysis rates using various amounts of lipase.

Incubations were studied by gel filtration. Results show: (i) During lipase action, three phases of lipids coexist: an emulsified phase, a micellar phase and an intermediate heavy phase sized between the two others. The equilibrium between each phase is dependent upon the bile salts concentration. (ii) Under these conditions, pancreatic lipase was at 60% bound to the emulsified phase, whereas pancreatic phospholipase A2 was bound at 94% to the micellar phase.
The relative incorporation of arachidonic and eicosapentaenoic acids into human platelet phospholipids
Authors: Weaver B. J. , Holub B. J.
Published: November 2006

The incorporation of arachidonic acid (AA) as compared to eicosapentaenoic acid (EPA) into human platelet phospholipids was tested by incubating washed platelets with a known mixture of [3H]AA and [14C]EPA. Following incubation, the platelet lipids were extracted, the individual phospholipids—phosphatidylcholine (PC), phosphatidylserine (PS), phosphatidylinositol (PI) and phosphatidylethanolamine (PE)—were separated by thin layer chromatography, and their corresponding [3H]/[14C] ratios were determined. Based on a [3H]/[14C] ratio of unity for the substrate mixture, the PC, PS, PI and PE exhibited ratios of 0.55, 0.93, 1.12 and 0.74, respectively, which were significantly different from 1.00 in all instances except in the case of PS. These results indicate that PC and PE selectively incorporated EPA, while PI showed preference toward AA. These selectivities may account partly for the differing AA/EPA mass ratios that have been observed among the individual phospholipids of human subjects consuming fish oils.
Analysis of positional distribution of fatty acids in palm oil by13C NMR spectroscopy
Authors: Ng Soon
Published: November 2006

The13C NMR spectrum of the carbonyl carbons of the acyl groups of triacylglycerols of palm oil has been shown to give the composition of saturated, oleic and linoleic acyl groups at the 1,3‐positions and at the 2‐position of the glycerol moiety. Except for the lack of differentiation of the saturated fatty acids, the13C NMR technique provides the same information as the tedious enzymatic hydrolysis cum fatty acid analysis. The carbonyl carbon of the linolenic acyl group (18∶3,[cis, cis, cis]‐9, 12, 15) has a chemical shift which is only 0.005 ppm to low frequency of that of the linoleic acyl group (18∶2,[cis, cis]‐9, 12), so that the two resonances may not be distinguishable (or resolved) even at a high magnetic field.
Quantitative relationships between dietary linoleate and prostaglandin (Eicosanoid) biosynthesis
Authors: Mathias Melvin M. , Dupont Jacqueline
Published: November 2006

Essential fatty acid deficiency consistently depresses eicosanoid (prostaglandin E2, F2, and I2and thromboxane) biosynthesis independent of sampling protocols. Tissue fatty acid analyses support the hypothesis that the decrease is due in part to depression of arachidonate and accumulation of eicosatrienoate (n−9). Research on the alteration of eicosanoid biosynthesis by dietary linoleate supplementation is reviewed extensively. Responses of whole blood, lung, liver and heart eicosanoid synthesis to feeding eight concentrations of dietary linoleate between 0 and 27 energy percent are reported. It is concluded that stimulation, depression and no change in eicosanoid production could be equally well documented as a response to linoleate supplementation. Evidence for the obvious mechanism that alterations in precursor fatty acid composition are a possible explanation is fragmentary and inconsistent. The appropriate sampling techniques appear not to be established at this time and most likely are species, gender and tissue specific.
Cholesterol and triglyceride distributions in an adult employee population: The Pacific Northwest Bell Telephone Company health survey
Authors: Hoover J. Joanne , Walden Carolyn E. , Bergelin Robert O. , Wahl Patricia W. , Albers John J. , Hazzard William R. , Knopp Robert H.
Published: November 2006

Plasma cholesterol and triglyceride are presented for 4503 adult employees of the Pacific Northwest Bell Telephone Company. Cross‐sectional age and sex specific means and percentiles are shown. Females are classified by use or nonuse of exogenous sex hormones. Comparisons are examined among these groups, between blacks and whites, and among education and occupation categories. In these cross‐sectional data, cholesterol and triglyceride generally increase with age and exhibit distinct differences by sex and by hormone use.
The influence of linoleic acid intake on electron transport system components
Authors: Abuirmeileh N. M. , Elson C. E.
Published: November 2006

Groups of young rats were fed a basal diet with beef tallow (BT) or corn oil (CO) added to provide 4 or 19% energy as linoleic acid. Mitochondria isolated from the livers of the rats fed the CO contained a significantly lower concentration of b‐type cytochrome and significantly higher concentrations of cytochromes c, c1 and aa3. Cytochrome c oxidase activity also was elevated. The spectral characteristics of the b‐type cytochrome varied between the 2 groups. The mitochondria from the rats fed CO contained relatively more of the cytochrome b‐558 component whereas mitochondria from the BT group contained more of the cytochrome b‐562 component. The classical antimycin A inhibition of electron transport between cytochromes b and c1 was partially bypassed in mitochondria with the more fluid membrane. The activation energy for cytochrome c oxidase in mitochondria from this group was significantly higher. These differences may be traced to the physical characteristics of the inner mitochondrial membrane.
Phthalic ester, an artifactual contaminant in diazomethane prepared from N‐methyl‐N‐nitroso‐p‐toluenesulfonamide for the derivatization of prostaglandins
Authors: Mai J. , Kinsella J. E. , Chou J. S.
Published: November 2006

During analyses of prostaglandin (PG) methoxime methyl trimethylsilyl (MO‐ME‐TMS) ether derivatives by gas chromatography, we consistently observed a contaminant peak which we identified as di‐2‐ethylhexyl phthalate (DEHP). The diazomethane prepared from N‐methyl‐N‐nitroso‐p‐toluenesulfonamide (MNTSA) using the Diazald kit was the major source of DEHP. Several other materials also were significant sources. The concentrations of DEHP in these materials were quantified by gas chromatography‐mass spectrometry.
Fatty acid profile of myocardial lipid in populations consuming different dietary fats
Authors: Shenolikar Indushekhar
Published: November 2006

Human hearts from medico‐legal autopsies were obtained from 3 regions of India where the edible oils used are different. These 3 population groups consumed either mustard oil (Calcutta), coconut oil (Trivandrum) or peanut oil (Madras). Among the saturated fatty acids, lauric acid was found only in the myocardium of subjects from Trivandrum (3.5% of the total fatty acids [TFA]), heptadecanoic acid only in the samples from Madras (1.4% TFA) and arachidic acid only in those of Calcutta (1.9% TFA). Erucic acid was present only in the samples received from Calcutta and acted as a marker of mustard oil consumption. It had a mean concentration of 5.6% TFA. From the level of erucic acid present in the myocardial lipid, it is apparent that, at the level of intake of mustard oil prevalent in India, the risk of developing myocardial fibrosis is slight.
Comparison of fatty acids and lipids of smolting hatchery‐fed and wild atlantic salmonSalmo salar
Authors: Ackman R. G. , Takeuchi Toshio
Published: November 2006

In Atlantic Canada the Atlantic salmonSalmo salar change from the parr stage to the smolt stage while still in fresh water, preparatory to migration to salt water. In some stocks this takes place during the second overwintering. In several hatcheries where the water temperature drops to 0–0.5 C and the ponds ice over, there is a high incidence of erosion of the dorsal and pectoral fins and sometimes of the caudal fin. No disease organism has been identified, and the lesions heal over in most cases. Dietary fatty acids were thought, to be a factor. A detailed study of lipid recoveries and classes has shown that in the skins of abnormal fish the total lipid, is 7.8% compared to 4.7% in control fish.

Unexpectedly, an analysis of one lot of healthy smoltstage wild fish showed that whole bodies have only a quarter of the lipid of comparble hatchery fish. Comparison of fatty acids showed that wild fish lipids include a higher proportion of arachidonic acid than those of the hatchery fish. in the latter, linoleic acid is provided readily by diet but the elongation to arachidonic acid evidently does not proceed. These results suggest that the smolt lipid, is involved intimately with either the cause of the dermal lesion or is a defense mechanism, possibly mediated through oxygenase activity.
Distribution of14C after oral administration of (U‐14C)labeled methyl linoleate hydroperoxides and their secondary oxidation products in rats
Authors: Oarada Motoko , Miyazawa Teruo , Kaneda Takashi
Published: November 2006

To study the toxicity of low molecular weight (LMW) compounds formed during the autoxidation of oils,14C‐labeled primary monomeric compounds (methyl linoleate hydroperoxides) and secondary oxidation products, i.e., polymer and LMW compounds prepared from autoxidized methyl [U‐14C]linoleate hydroperoxides (MLHPO) were orally administered to rats, and their radioactive distributions in tissues and organs were compared. The polymeric fraction consisted mainly of dimers of MLHPO. For the LMW fraction, 4‐hydroxy‐2‐nonenal, 8‐hydroxy methyl octanoate and 10‐formyl methyl‐9‐decenoate were identified as major constituents by gas chromatography‐mass spectrometry (GC‐MS) after chemical reduction and derivatization. When LMW compounds were administered to rats,14CO2 expiration and the excreted radioactivity in urine in 12 hr were significantly higher than those from polymer or MLHPO administration. Maximum14CO2 expiration appeared 2–4 hr after the dose of LMW compounds. Radioactivity of the upper part of small intestines six hr after the dose of LMW compounds was higher than the values from administered polymer or MLHPO. The remaining radioactivity in the digestive contents and feces 12 hr after administration of LMW compounds was much lower than the values observed from administered polymer or MLHPO. Among internal organs, the liver contained the highest concentration of radioactivities from polymer, MLHPO and LMW fractions, and an especially higher level of radioactivity was found in liver six hr after the administration of LMW compounds. Six hours after the dose of LMW compounds, a relatively higher level of radioactivity also was detected in kidney, brain, heart and lung. These results show that the LMW compounds from MLHPO autoxidation are more easily absorbed in rat tissues than polymer and MLHPO.
Effect of clofibrate on cholesterol metabolism in rats treated with polychlorinated biphenyls
Authors: Nakagawa M. , Shimokawa T. , Noguchi A. , Ishihara N. , Kojima S.
Published: November 2006

Serum and hepatic cholesterol content in rats treated with polychlorinated biphenyls (PCBs, KC‐400) were increased compared to those of control rats. This increase of cholesterol content was reduced to control level by simultaneous administration of ethyl p‐chlorophenoxyisobutyrate (CPIB). Also, when lecithin‐cholesterol acyltransferase (LCAT) (EC. 2.3.1.43) activity was expressed as the net cholesterol esterification, the acyltransferase activity in rats treated with PCBs was elevated, while the elevated acyltransferase activity was brought to control level by simultaneous administration of CPIB. On the other hand, the amount of bile of rats treated with CPIB, PCBs and PCBs‐CPIB was increased, but free and total cholesterol content in bile of these treated rats was decreased to 40–60% of those of control rats. Moreover, cytochrome P‐450 content in liver microsomes of rats treated with CPIB, PCBs and PCBs‐CPIB was increased. At the same time, cholesterol‐metabolizing activity in liver microsomes of rats treated with CPIB, PCBs and PCBs‐CPIB also was elevated. Similar results were obtained for drug metabolizing (aniline hydroxylation and aminopyrine N‐demethylation) activity. In addition, the amount of bile acids excreted from rats treated with CPIB, PCBs and PCBs‐CPIB was increased compared to that of control rats.

These results suggest that hypercholesterolemia induced by oral ingestion of PCBs is recovered by CPIB treatment and that this hypocholesterolemic effect of CPIB may be related partly to the elevation of hepatic mixed function oxidase activity for cholesterol catabolism.