bluuebunny/crossref_metadata_2025 huggingface dataset:
The effect of enhanced intake of linoleic acid on the fatty acid composition of tissue polar lipids of post‐smolt atlantic salmon (Salmo salar)
Authors: Bell J. Gordon , Youngson Arthur , Mitchell Alexander I. , Cowey Colin B.
Published: November 2006

Duplicate groups of Atlantic salmon (Salmo salar) post smolts were given diets in which the lipid component was either fish oil or a mixture of corn oil and lard. This difference in the dietary lipid did not significantly affect growth over a period of sixteen weeks.

Proportions of docosahexaenoic acid [22∶6(n−3)] and total (n−3) fatty acids in the polar lipids of liver and white muscle were unaffected by this difference in dietary lipid component over the time period used. Fish given the diet containing corn oil and lard had significantly higher levels of 20∶2(n−6), 20∶3(n−6) and 20∶4(n−6) in the polar lipids of these tissues than were present in the tissues of the fish given diets containing fish oil. There results suggest that linoleic acid [18∶2(n−6)] undergoes elongation and desaturation to arachidonic acid [20∶4(n−6)] in post‐smolt Atlantic salmon.
Microsomal Δ5 desaturation of eicosa‐8,11,14‐trienoic acid is activated by a cytosolic fraction
Authors: Leikin Alicia L. , Brenner Rodolfo R.
Published: November 2006

Δ5 Desaturation of eicosa‐8,11,14‐trienoic acid to arachidonic acid was studied in rat liver microsomes. It was shown that Δ5 desaturation of fatty acids in vitro requires the participation of a peripheral component of cytosolic origin. Desaturation of 20∶3n−6 to 20∶4n−6 decreases in washed microsomes as they lose an adsorbed cytosolic fraction (CF), but the enzymatic activity can be recovered as a function of CF concentration in the incubation medium. Albumin does not substitute for CF. Δ5 Desaturation of 20∶3n−6 is inhibited by arachidonic acid by a product inhibition effect, but CF prevents retroinhibition of Δ5‐desaturase by 20∶4n−6. This ability of CF is eliminated by preincubation of CF with 20∶4n−6, but not with γ−18∶3n−6, the product of Δ6 desaturation of 18∶2n−6, thus indicating that CF impairs the retroinhibitory effect of arachidonic acid on Δ5‐desaturase in a specific manner. Δ6 Desaturation of linoleic acid to γ−18∶3n−6 is also activated by CF and retroinhibited by γ−18∶3n−6. CF activity on Δ6 desaturation is retained after preincubation with 20∶4n−6, but it is lost after preincubation with γ−18∶3n−6. Activation of Δ6‐desaturase by CF is associated with the removal of the reaction product in a specific manner. Chromatography of CF by Sephacryl S‐200 separates two major subfractions which show different efficiency in reactivating Δ5‐ and Δ6‐desaturase activities in washed microsomes. Therefore, CF may contain subfractions that can prevent Δ5‐ and δ6‐desaturase retroinhibition by apparently binding their respective reaction products specifically.
Cholesterol metabolism in frog (Rana esculenta) liver: Seasonal and sex‐related variations
Authors: Bruscalupi G. , Castellano F. , Scapin S. , Trentalance A.
Published: November 2006

Many aspects of lipid metabolism have been studied in amphibians, but seasonal lipid modulation in male and female frogs has not been investigated. We describe here the yearlong patterns of hepatic lipid content and enzyme activities related to cholesterol homeostasis, 3‐hydroxy‐3‐methylglutaryl coenzyme A (HMG‐CoA) reductase activity and acyl coenzyme A:cholesterol acyltransferase (ACAT) activity in liver of the male and female frog,Rana esculenta. Lipid storage follows distinct seasonal patterns, with an increase in June that is more pronounced in the female than in the male frog. Cholesterol content and cholesterol storage as cholesteryl ester in male liver are consistent with the activity of HMG‐CoA reductase and of ACAT enzymes. HMG‐CoA reductase activity of the female frog shows an extra peak in fall unrelated to cholesterol storage and probably related to the production of essential compound for oogenesis.
Analysis of seed oils containing cyclopentenyl fatty acids by combined chromatographic procedures
Authors: Christie William W. , Brechany Elizabeth Y. , Shukla Vijai K. S.
Published: November 2006

The fatty acids of seed oils of the Flacourtiaceae,Hydnocarpus anthelmintica, Caloncoba echinata andTaraktogenus kurzii, have been examined by a combination of capillary gas chromatography, silver ion high performance liquid chromatography and gas chromatography‐mass spectrometry. In addition to the common range of cyclopentenyl fatty acids found in such oils, 13‐cyclopent‐2‐enyltridec‐4‐enoic acid was a major component ofH. anthelmintica and was identified by mass spectrometry as its picolinyl ester and dimethyldisulphide adduct. It has not previously been found in nature. In the other seed oils, the isolated double bond in the corresponding fatty acid was in position 6, as expected. Similarly,cis‐4‐hexadecenoic acid and C16 and C18 cyclopentyl fatty acids were identified for the first time inH. anthelmintica. Iso‐ andanteiso‐methylbranched fatty acids were present in trace amounts.
Capillary gas chromatography and tandem mass spectrometry of paf‐acether and analogs: Absence of 1‐O‐alkyl‐2‐propionyl‐sn‐glycero‐3‐phosphocholine in human polymorphonuclear neutrophils
Authors: Bossant M. J. , Farinotti R. , De Maack F. , Mahuzier G. , Benveniste J. , Ninio E.
Published: November 2006

Fast atom bombardment‐tandem mass spectrometry was used to identify molecular species of paf‐acether (paf) produced by human polymorphonuclear neutrophils. Using this biological material, normal phase high performance liquid chromatography was necessary prior to the fast atom bombardment‐tandem mass spectrometry step. Gas liquid chromatography/electron capture detection after hydrolysis with phospholipase C and conversion to heptafluorobutyrate derivatives was used to confirm the results. The results indicated the presence of mainly 1‐O‐hexadecyl/octadecyl‐2‐acetyl‐sn‐glycero‐3‐phosphocholine, acyl analogs of paf and only trace amounts of other alkyl analogs of paf. We did not detect the 2‐propionyl analog of paf. Moreover, supplementation of human polymorphonuclear neutrophils with sodium propionate did not result in formation of the 2‐propionyl analog of paf.
Thiobarbituric acid‐reactive malondialdehyde formation during superoxide‐dependent, iron‐catalyzed lipid peroxidation: Influence of peroxidation conditions
Authors: Janero David R. , Burghardt Barbara
Published: November 2006

A systematic study of the influence of biological lipid peroxidation conditions on lipid hydroperoxide decomposition to thiobarbituric acid‐reactive malondialdehyde is presented. A superoxide‐dependent, iron‐catalyzed peroxidation system was employed with xanthine oxidase plus hypoxanthine plus ferric iron‐adenosine diphosphate complex as free radical generator. Purified cardiac membrane phospholipid (as liposomes) was the peroxidative target, and 15‐hydroperoxy‐eicosatetraenoic acid was used as a standard lipid hydroperoxide. Exposure of myocardial phospholipid to free radical generator at physiological pH (7.4) and temperature (37°C) was found to support not only phospholipid peroxidation, but also rapid lipid hydroperoxide breakdown and consequent malondialdehyde formation during peroxidation. Under lipid peroxidation conditions, oxidative injury to the phospholipid polyunsaturated fatty acids required superoxide radical and ferric iron‐adenosine diphosphate complex, whereas 37°C temperature and trace iron were sufficient for lipid hydroperoxide decomposition to malondialdehyde. Harsh thiobarbituric acid‐test conditions following peroxidation were not mandatory for either lipid hydroperoxide breakdown or thiobarbituric acid‐reactive malondialdehyde formation. However, hydroperoxide decomposition that had begun in the peroxidation reaction could be completed during a subsequent thiobarbituric acid test in which no lipid autoxidation took place. Iron was more critical than heat in promoting the observed hydroperoxide decomposition to malondialdehyde during the lipid peroxidation reaction at 37°C and pH 7.4. These data demonstrate that the radical generator, at physiological pH and temperature, serves a dual role as both initiator of membrane phospholipid peroxidation and promotor of lipid peroxide breakdown and thiobarbituric acid‐reactive malondialdehyde formation. Consequently, peroxidation reaction conditions can directly influence lipid hydroperoxide decomposition, malondialdehyde production and system thiobarbituric acid‐reactivity. In vivo, decomposition of lipid peroxides to malondialdehyde during radical‐mediated, metal‐catalyzed membrane peroxidation may represent an integral component of oxidative tissue injury rather than a mere consequence of hydrolyzing the peroxidized biological sample in a thiobarbituric acid test.
Alpha‐ and gamma‐tocopherol levels in lipoproteins fractionated by affinity chromatography
Authors: Clevidence Beverly A. , Lehmann Joanna
Published: November 2006

Alpha‐ and gamma‐tocopherol levels of nine women were measured in whole serum and in serum lipoproteins separated by heparin affinity chromatography. Alphatocopherol levels (mean±SD) in whole serum, low density plus very low density lipoproteins and high density lipoproteins were 10.8±2.7, 6.4±1.6 and 4.6±1.4 (μg/ml), respectively. Corresponding values (μg/ml) for gamma‐tocopherol were 1.2±0.5, 0.7±0.3 and 0.6±0.2. Recoveries of serum alpha‐ and gamma‐tocopherol from the heparin columns were 102±5% and 105±7%, respectively. Serum alpha‐tocopherol was linearly correlated with components of high density lipoprotein (apolipoproteins, high density lipoprotein cholesterol), but not with serum total lipids or indices of low density lipoprotein, even though high density lipoprotein carried less than half of the serum alpha‐tocopherol. However, serum gamma‐tocopherol was highly correlated with indices of serum lipids, such as serum cholesterol (r=0.92, p=0.005). The coefficient for the correlation of low density lipoprotein (+very low density lipoprotein) tocopherol with high density lipoprotein tocopherol was r=0.66 (p=0.06) for alpha‐tocopherol and r=0.84 (p=0.004) for gamma‐tocopherol. These differences in the relationships of the two tocopherols to lipids and lipoproteins support the view that when the two tocopherols are present at normal dietary levels, gamma‐tocopherol partitions between lipoproteins based on their relative lipid content, but a portion of the alpha‐tocopherol in high density lipoprotein is specifically bound.
Fatty acid pattern of tissue phospholipids in copper and iron deficiencies
Authors: Johnson Susan B. , Kramer Tim R. , Briske‐Anderson Mary , Holman Ralph T.
Published: November 2006

Because copper and iron have been reported to be essential cofactors in Δ9 desaturation of fatty acids, the effects of different dietary intakes of copper and iron on tissue fatty acids were studied. Male Long‐Evans rats (ten per group) were fed diets containing adequate, deficient or excess copper or iron. On day 42 of the dietary regimen, the animals were killed and tissues and blood were removed for analysis of metals and fatty acids of phospholipids. Compared with the copper‐adequate rats, the copper‐deficient rats showed increased 18∶0 in liver and decreased 16∶1ω7 in liver, heart and serum. There were no differences for 16∶0 or 18∶1ω9. Intake of excess copper did not cause an increase in products of Δ9 desaturation. Comparisons between iron‐deficient and iron‐adequate rats showed that iron deficiency increased 18∶2ω6 in liver and serum and decreased 20∶4ω6 in serum only. Relative percentages of 16∶0, 18∶0, 16∶1ω7 and 18∶1ω9 in liver and serum phospholipids were similar for both groups. Intake of excess iron caused a decrease in 18∶2ω6; and 16∶0 and 18∶1ω9 were higher in the liver of the iron‐excess group than the iron‐deficient group. This study did not support the requirement for copper or iron in the Δ9 desaturation of fatty acids as expressed in phospholipids of liver, heart and serum.
Eskimo plasma constituents, dihomo‐γ‐linolenic acid, eicosapentaenoic acid and docosahexaenoic acid inhibit the release of atherogenic mitogens
Authors: Smith Donald L. , Willis Anthony L. , Nguyen Ngoc , Conner Debra , Zahedi Shaye , Fulks Judy
Published: November 2006

Studies in man and laboratory animals suggest that ω3 polyunsaturated fatty acid consituents of fish oils have antiatherosclerotic properties. We have studied the effects of several such polyunsaturated fatty acids for ability to modify the in vitro release of mitogens from human platelets. Such mitogens may produce the fibroproliferative component of atherosclerotic plaques. Both 5,8,11,14,17‐eicosapentaenoic acid (20∶5ω3) and 4,7,10,13,‐16,19‐docosahexaenoic acid (22∶6ω3), major constituents of fish oils, inhibited adenosine diphosphate‐induced aggregation of platelets and the accompanying release of mitogens. These effects are dose dependent. Linolenic acid (18∶3ω3), the biosynthetic precursor of eicosapentaenoic acid, also inhibited platelet aggregation and mitogen release. Eicosapentaenoic acid also inhibited mitogen release from human monocyte‐derived macrophages, which, in vivo, are an additional source of mitogens during atherogenesis.

Potent inhibition of human platelet aggregation and mitogen release was also seen with dihomo‐γ‐linolenic acid (8,11,14‐eicosatrienoic acid 20∶3ω6), whose levels are reportedly elevated in Eskimos subsisting on marine diets.

We conclude that diets that elevate plasma and/or tissue levels of eicosapentaenoic acid, docosahexaenoic acid and dihomo‐γ‐linolenic acid precursor γ‐linolenic acid (18∶3ω6) may exert antiatherosclerotic effects by inhibiting the release of mitogens from platelets and other cells.
Simple high performance liquid chromatography methods for monitoring lipase reactions
Authors: Ergan Françoise , André Gérald
Published: November 2006

This paper describes three simple high performance liquid chromatography methods to separate mixtures of free fatty acids, mixtures of different triglycerides and mixtures of all fat classes (monoglycerides, diglycerides, triglycerides and free fatty acids). It is possible with our methods to identify and quantify each peak of the chromatogram. These methods have been designed to monitor lipase reactions. Using a first set of conditions, we have been able to separate five fatty acids: linolenic, linoleic, palmitic, oleic and stearic, without any specific preparation of the samples. With a second set of conditions, we showed that the same mobile phase and the same column could separate both triglyceride species and fat classes. However, in the latter case, a flow gradient was used.
On the isolation of 2‐hydroxydocosanoic and 2‐hydroxytricosanoic acids from the marine spongeAmphimedon compressa
Authors: Carballeira Néstor M. , Lopez Mario R.
Published: November 2006

The first α‐hydroxy fatty acids from a marine sponge, namely 2‐hydroxydocosanoic and 2‐hydroxytricosanoic, were identified in the Caribbean spongeAmphimedon compressa. These acids were found to occur in phosphatidylethanolamine and phosphatidylserine and constituted 52% of the total fatty acid mixture of this sponge. The long chain fatty acids 5,9,23‐nonacosatrienoic (29∶3) and 5,9,23‐tricontatrienoic (30∶3), as well as a new tetratricontatetraenoic (34∶4) acid, were also found inA. compressa.
Long chain fatty acid deficits in brain myelin sphingolipids of undernourished rat pups
Authors: Yeh Yu‐Yan
Published: November 2006

A restricted maternal dietary intake (40% of ad libitum intake) is known to cause myelin deficit that is accompanied by decreased amounts of individual phospholipids and sphingolipids in brain myelin of suckling rats. This communication reports the effects of the same nutritional stress on the fatty acid composition of brain myelin lipids. In myelin of 19‐day‐old normally fed rats, palmitate (16∶0), stearate (18∶0) and oleate (18∶1) accounted for 80–90% of all fatty acids in phosphatidylcholine, phosphatidylethanolamine and phosphatidylserine. Maternal dietary restriction resulted in deficits of total fatty acid content, but did not affect the proportional distribution of individual fatty acids among phospholipids. By contrast, longer chain (22‐ and 24‐carbon) fatty acids accounted for more than half the fatty acid content of myelin cerebroside and sulfatide from the 19‐day‐old control rat pups. In undernourished rats of that age, proportions of lignocerate (24∶0) and nervonate (24∶1) in cerebroside and sulfatide were 40–50% lower than those in control rats. This, together with higher proportions of 16∶0, 18∶0 and 18∶1 and a higher ratio of C16−C20 to C22−C24 in under‐nourished than in control rats, suggests an impairment in fatty acid chain elongation. Ten days of nutritional rehabilitation failed to restore the fatty acid imbalances; however, after an additional 5 days of ad libitum feeding, the experimental and control values were similar. The undernutrition results in hypomyelination, which is characterized by a proportional decrease in lignoceric and nervonic acids of sphingolipids.
A novel bioaction of PAF: Induction of microbicidal activity in guinea pig bone marrow cells
Authors: Hayashi Hidetoshi , Kudo Ichiro , Kato Toshiyuki , Nozawa Ryushi , Nojima Shoshichi , Inoue Keizo
Published: November 2006

When guinea pig bone marrow cells were incubated in the presence of 10−8 to 10−6 M platelet activating factor (PAF) for 24 to 72 hr, microbicidal activity againstCandida parapsilosis of cells was augmented. This augmentation was inhibited by PAF‐specific antagonists, CV6209 or FR900452. PAF‐specific binding sites with a high affinity were found on guinea pig bone marrow cells. Carrageenan or 2‐chloroadenosine, reagents known to be preferentially cytotoxic to macrophages, abolished the microbicidal activity of PAF‐treated bone marrow cells. Macrophages prepared from the peritoneal cavity, however, acquired no appreciable microbicidal action by treatment with PAF. These observations suggest that PAF may affect a class of guinea pig bone marrow cells through binding to receptors specific to PAF, resulting in activation and/or induction of differentiation of monocyte‐macrophage lineage cells.
Erythrocyte contamination of leukocyte populations following density‐gradient centrifugation results in artificially high levels of human leukocyte HMG‐CoA reductase activity
Authors: Harwood H. James , Bridge Donna M. , Stacpoole Peter W.
Published: November 2006

When measuring human leukocyte HMG‐CoA reductase activity, special care must be taken to prevent erythrocyte contamination of the leukocyte layer during isopycnic centrifugation. Contamination during leukocyte isolation and subsequent erythrocyte lysis during NH4Cl treatment results in increased leukocyte microsomal HMG‐CoA reductase activity. Increased enzyme activity is not due to enzyme dephosphorylation, thiol‐disulfide reduction or increased enzyme protein concentration. Leukocyte populations containing granulocytes appear to be most sensitive. Prevention of erythrocyte contamination during isopycnic centrifugation should aid in accurate measurement of human leukocyte HMG‐CoA reductase activity.
Novel method to administer radiolabeled lipid to juvenile oysters
Authors: Erickson Marilyn C. , Selivonchick Daniel P.
Published: November 2006

Particles prepared from egg yolk were shown to encapsulate protein and to be in a size range that would be filtered by the oyster. A radiotracer study involving the addition of radiolabeled phosphatidylcholine to egg yolk demonstrated that the egg yolk particles were taken up and metabolized by juvenile oysters (Crassostrea gigas). Catabolism of the radiolabeled lipid and subsequent resynthesis into non‐lipid components occurred to a slight extent. The main factor responsible for the distribution of radioactivity amongst the lipids in the stomach tissue was believed to be transacylation.
Time course of dolichol and dolichyl phosphate in regenerating rat liver
Authors: Yamada Kouji , Murakami Manabu , Katayama Kouichi , Sato Tadashi
Published: November 2006

By using novel high performance liquid chromatographic methods, the time course of dolichol and dolichyl phosphate in regenerating rat liver was investigated and compared with that for cholesterol. The cholesterol level in the liver increased more rapidly than the level of dolichyl phosphate (Dol‐P). HMG‐CoA reductase activity correlated well with cholesterol concentration. The level of Dol‐P at day 1 was lower than that in normal liver, but was increased at three to five days after hepatectomy, which correlates well with mannosyl transferase activity. Dolichol decreased for three days, and thereafter increased until 11 days after hepatectomy. The compositions of dolichol and Dol‐P homologues did not change during the experimental period. The results indicate that the cholesterol content in regenerating rat liver increased first, followed by Dol‐P, and finally dolichol.
Free fatty acid inhibition of the insulin induction of glucose‐6‐phosphate dehydrogenase in rat hepatocyte monolayers
Authors: Salati Lisa M. , Adkins‐Finke Bonnie , Clarke Steven D.
Published: November 2006

Rat hepatocytes in monolayer culture were utilized to determine if the decrease in glucose‐6‐phosphate dehydrogenase (G6PD) activity resulting from the ingestion of fat can be mimicked by the addition of fatty acids to a chemically, hormonally defined medium. G6PD activity in cultured hepatocytes was induced several‐fold by insulin. Dexamethasone or T3 did not amplify the insulin induction of G6PD. Glucose alone increased G6PD activity in cultured hepatocytes from fasted donors by nearly 500%. Insulin in combination with glucose induced G6PD an additional two‐fold. The increase in G6PD activity caused by glucose was greater in hepatocytes isolated from 72 hr‐fasted rats as compared to fed donor rats. Such a response was reminiscent of the “overshoot” phenomenon in which G6PD activity is induced well above the normal level by fasting‐refeeding rats a high glucose diet. Addition of linoleate to the medium resulted in a significant suppression of insulin’s ability to induce G6PD, but linoleate had no effect on the induction of G6PD activity by glucose alone. A shift to the right in the insulin‐response curve for the induction of G6PD also was detected for the induction of malic enzyme and acetyl‐CoA carboxylase. Arachidonate (0.25 mM) was a significantly more effective inhibitor of the insulin action than linoleate was. Apparently rat hepatocytes in monolayer culture can be utilized as a model to investigate the molecular mechanism by which fatty acids inhibit the production of lipogenic enzymes. In part, this mechanism of fatty acid inhibition involves desensitization of hepatocytes to the lipogenic action of insulin.
Metabolism of sitosteryl β‐D‐glucoside and its nutritional effects in rats
Authors: Weber Nikolaus
Published: November 2006

[4‐14C]Sitosteryl β‐D‐glucoside, intragastrically administered to rats, was not absorbed by the intestinal mucosa. At three hr after the application, radioactivity was concentrated almost exclusively in the digesta of stomach, small intestine as well as cecum and colon, whereas only low proportions of radioactively labeled compounds were found in the various tissues of the gastrointestinal tract. Minor proportions of labeled metabolites of [4‐14C]sitosteryl β‐D‐glucoside, such as sitosterol and sitosteryl esters, were formed in the small intestine in vivo and in slices of small intestine in vitro. In the tissues of cecum and colon as well as the digesta derived from them, high proportions of labeled coprositostanol, i.e. 24α‐ethyl‐5β‐cholestan‐3β‐ol, that obviously had been formed by bacterial degradation of the substrate were detected.

The feeding of sitosteryl β‐D‐glucoside (0.5 g/kg body weight×day) over a period of four weeks did not alter significantly body weights or organ weights of rats. Analyses of steryl lipids of the various organs and tissues confirmed the findings obtained with the radioactive substrate: neither sitosteryl β‐D‐glucoside nor sitosterol or sitosteryl esters derived therefrom had been transported in appreciable amounts to organs and tissues outside the alimentary canal during the feeding period. Minor proportions of unmetabolized sitosteryl β‐D‐glucoside were detected in the tissues of stomach and intestine, whereas large proportions of the substrate were found in feces of rats that had received the sitosteryl β‐D‐glucoside‐containing diet; coprositostanol was found in feces of these animals in high proportions as well. Thus, the use of sitosteryl β‐D‐glucoside as emulsifier or preservative in food and feed does not appear to involve any risk.
Regulation of squalene epoxidase activity by membrane fatty acid composition in yeast
Authors: Buttke T. M. , Brint S. L. , Lowe M. R.
Published: November 2006

DeprivingSaccharomyces cerevisiae strain GL7 of exogenous unsaturated fatty acid supplements causes this sterol biosynthetic mutant to accumulate squalene at the expense of squalene epoxide and squalene diepoxide. To further characterize the apparent relationship between squalene epoxidase activity and membrane fatty acid composition, a variety of unsaturated fatty acids differing in their chain lengths and in the positions and orientation (cis ortrans) of their double bonds were tested for their ability to promote turnover of endogenous squalene in cells previously deprived of olefinic supplements. All of the unsaturated fatty acids tested were found to restore squalene epoxidase activity but there were marked differences in their efficacies that best were correlated with the extent to which they reduced the medium chain (C‐10+C‐12) saturated fatty acid content of cellular phospholipids. Additional studies demonstrated that de novo protein synthesis was required for the restoration of squalene epoxidase activity in unsaturated fatty aciddeprived cells.
Effects of cholestanol feeding and cholestyramine treatment on the tissue sterols in the rabbit
Authors: Buchmann Marie S. , Clausen Ole P.
Published: November 2006

Rabbits were fed diets enriched with cholestanol or cholestereol (3.5 g/wk) for 4–12 weeks. During cholestanol feeding, the concentration of cholestanol in blood serum, liver, heart and aorta increased 15–30 times. In serum and liver, the concentration of cholesterol also increased. Cholestanol‐fed rabbits developed inflammatory changes in the liver, with proliferation of small bile ducts. Liver tests were only slightly abnormal. Morphological atherosclerosis of the aorta was only occasionally seen in rabbits receiving cholestanol for eight weeks or less.

During cholesterol feeding, the amounts of cholesterol in different tissues increased dramatically, most in the aorta. Morphological atherosclerosis in the aorta was found in all rabbits fed cholesterol‐enriched diets for more than four weeks. Brain cholestanol was doubled in rabbits fed cholestanol for eight weeks, whereas brain sterols did not change significantly during cholesterol feeding. After an additional regression period with cholestyramine for eight weeks, the increased content of cholestanol in the brain was unchanged in cholestanol‐fed rabbits. These observations are discussed in relation to the cholestanolosis of the brain that develops in the rare inherited human disease cerebrotendinous xanthomatosis.
Dominance of Δ7‐sterols in the family caryophyllaceaein the family caryophyllaceae
Authors: Salt Thomas A. , Adler John H.
Published: November 2006

The predominant 4‐desmethylsterols from the leaves of 12 species in 11 genera of the family Caryophyllaceae are 24‐ethyl‐Δ7‐sterols. In eight species,Scleranthus annus L.,Paronychia virginica Spreng.,Lychnis alba Mill.,Silene cucubalus Wibel,Dianthus armeria L.,Gypsophilia paniculata L.,Saponaria officinales L. andMyosoton aquaticum (L.) Moench, the major sterols are spinasterol (24α‐ethylcholesta‐7,22E‐dien‐3β‐ol) and 22‐dihydrospinasterol (24α‐ethylcholest‐7‐en‐3β‐ol), with spinasterol at more than 60% of the desmethylsterol in the latter six species. Both 24α‐and 24β‐ethyl‐Δ7‐sterols are present in two species,Minuartia caroliniana Walt. andSpergula arvensis L., which possess 24β‐ethylcholesta‐7,25(27)‐dien‐3β‐ol and 24β‐ethylcholesta‐7,22E,25(27)‐trien‐3β‐ol as well as spinasterol and 22‐dihydrospinasterol.Cerastium arvense L.,C. vulgatum L. andArenaria serpyllifolia L. possess 24‐alkyl‐Δ5 and Δ7‐sterols. These three species synthesize sitosterol (24α‐ethylcholest‐5‐en‐3β‐ol), 24ζ‐methylcholest‐5‐en‐3β‐ol, spinasterol, 22‐dihydrospinasterol and the stanols, sitostanol (24α‐ethyl‐5α‐cholestan‐3β‐ol) and 24ζ‐methyl‐5α‐cholestan‐3β‐ol. Avenasterol (24‐ethylcholesta‐7,24(28)Z‐dien‐3β‐ol) was also isolated from five species. Sterol biosynthetic capability may be a useful characteristic in examining the taxonomic relatedness of plants in the Caryophyllaceae.
Spectroscopic investigations of the water pool in lecithin reverse micelles
Authors: Kumar V. V. , Raghunathan P.
Published: November 2006

The nature of the water pool formed in the reverse micellar system, lecithin/nonpolar solvent/water, has been investigated by means of near infrared, ultraviolet, fluorescence emission and visible spectroscopic techniques. The three nonpolar solvents chosen in this study were benzene, carbon tetrachloride and cyclohexane. Near infrared spectroscopic studies revealed that the amount of water present in the bulk organic phase is negligible at all water concentrations studied in all three solvents. The results of the polarity probe and 8‐anilinonaphthalene sulfonic acid (ANSA) fluorescence emission maxima studies indicate that the polarity of the water pool is much lower than that of bulk water. The difference in polarity between the water pool and bulk water decreases with increasing water concentration in benzene and carbon tetrachloride systems. However, in the cyclohexane system, at a water content of 6 moles of water per mole of lecithin, where the system is known to change from isotropic reverse micelle to anisotropic liquid crystalline state, the polarity of the water pool is found to decrease.
Specific induction of lauric acid ω‐hydroxylase by clofibrate, diethylhexyl‐phthalate and 2,4‐dichlorophenoxyacetic acid in higher plants
Authors: Salaün Jean‐Pierre , Simon Annick , Durst Francis
Published: November 2006

Recently, we have found in plant microsomes two laurate hydroxylases that catalyze the terminal hydroxylation or the in‐chain hydroxylation of the fatty acid. These two hydroxylases, which are both cytochrome P‐450 enzymes, are never found in the same plant. This study shows that the hypolipidemic drug clofibrate induces the lauric acid ω‐hydroxylase activity inVicia and soybean seedlings. The marked increase in activity (>20‐fold) produced by clofibrate was dose‐dependent but was not paralleled by an enhancement of bulk cytochrome P‐450 or cinnamic acid 4‐hydroxylase. Compounds related to clofibrate by structure (2,4‐dichlorophenoxyacetic acid) or effects (diethylhexyl‐phthalate) also stimulated the ω‐hydroxylating system in these plants. In contrast, the lauric acid in‐chain hydroxylase from Jerusalem artichoke tubers was induced less than cinnamic acid 4‐hydroxylase activity and bulk cytochrome P‐450 in tissues incubated in clofibrate solution. This suggests that clofibrate induces preferentially the laurate ω‐hydroxylating isozyme in plants.
A phospholipase C with a high specificity for platelet‐activating factor in rabbit liver light mitochondria
Authors: Nishihira Jun , Ishibashi Teruo
Published: November 2006

The light mitochondrial fraction from rabbit liver was found to catalyze the hydrolysis of platelet‐activating factor (PAF, 1‐O‐alkyl‐2‐acetyl‐sn‐glycero‐3‐phosphocholine) by the phospholipase C reaction to form 1‐O‐alkyl‐2‐acetyl‐glycerol and phosphocholine. The highest specific phospholipase C activity occurred in the liver and kidney. A subcellular survey showed that the enzyme was of lysosomal origin. The enzyme was solubilized with 2% Triton X‐100 from rabbit liver light mitochondria and purified ca. 600‐ to 700‐fold with a 17% yield using procedures that included hydroxyapatite, Sepharose 4B and isoelectric focusing column chromatography followed by fast protein liquid chromatography. The enzyme consists of two forms having a pl of 4.7 and 5.8. Each form was purified to a homogeneous state as judged by sodium dodecyl sulfate‐polyacrylamide disc gel electrophoresis. The enzyme migrated to positions corresponding to apparent molecular weights of 33,000 and 75,000, respectively. The purified enzymes of pl 4.7 and 5.8 had pH optima of 8.2 and 8.5 and apparent Km values of 55.6 and 45.5 μM for PAF, respectively. Furthermore, their phospholipase C activity was significantly inhibited by the addition of 1 mM EDTA. EDTA‐inactivated enzyme, however, recovered completely upon addition of Ca2+ to the original level. p‐Chloromercuribenzoate markedly inhibited enzyme activity, suggesting that phospholipase C is a—SH enzyme. The physiological role of the enzyme should be evaluated, considering its specificity for a highly potent, biologically active ether‐phospholipid.
Influence of dietary vitamin E, selenium and age on regional distribution of α‐tocopherol in the rat brain
Authors: Meydani Mohsen , Macauley John B. , Blumberg Jeffrey B.
Published: November 2006

Concentrations of α‐tocopherol (α‐T) in plasma, cerebrum, cerebellum, midbrain and brain stem and activity of selenium (Se)‐dependent glutathione peroxidase (GSH‐Px) in plasma were measured in 1‐ and 15‐month‐old male F344 rats fed diets containing vitamin E (E, IU/kg) and Se (ppm) in the following combinations: 30 E, 0.1 Se (control diet, minimum requirements); 200E, 0.2 Se; 0.0 E, 0.2 Se; 200 E, 0.0 Se; 0.0 E, 0.0 Se for 8 or 20 weeks. α‐T and GSH‐Px levels in plasma were reflective of dietary treatment in young rats in which an interaction of the two nutrients was noted. A longer period of dietary vitamin E deficiency was necessary to deplete plasma α‐T and depress GSP‐Px activity significantly in the old rats. Among the brain regions of all ages, cerebrum and midbrain had the highest concentrations of α‐T while cerebellum showed the lowest. However, cerebellum of young rats and cerebellum and brain stem of old rats had a greater α‐T accumulation with doubly supplemented diets, whereas only cerebellum of young and old rats showed a marked increased of α‐T with vitamin E supplementation. In old rats, vitamin E deficiency resulted in greater depletion of α‐T in cerebellum and brain stem than cerebrum and midbrain regions. Se deficiency in brain stem of young and old rats significantly decreased α‐T accumulation by vitamin E supplementation. Se supplementation marginally alleviates vitamin E depletion in brain. Cerebellum and brain stem of old rats fed the minimum requirements of vitamin E and Se for 20 weeks showed a significant decline in α‐T. Therefore, cerebellum and brain stem appear, to have a higher turnover of α‐T than cerebrum and midbrain, and older rats may require a higher level, of vitamin E in the diet to maintain steady state levels of α‐T in these regions.
A highly active soluble diacylglycerol synthesizing system from developing rapeseed,Brassica napusL.
Authors: Murphy Denis J.
Published: November 2006

The subcellular distribution of the enzymes of triacylglycerol biosynthesis has been studied in developing oilseed rape. All in vitro enzymatic activities from oleoyl‐CoA to triacylglycerol were sufficient to account for the known rate of oleate deposition in triacylglycerol in vivo. The enzymatic activities from oleoyl‐CoA to diacylglycerol preferentially were localized in a 150,000 g supernatant fraction, while the diacylglycerol acyl‐transferase mostly was associated with the microsomal (20,000 g pellet and 150,000 g pellet) and oil‐body fractions. The soluble (150,000 g supernantant) fraction rapidly incorporated oleate from [1‐14C]oleoyl‐CoA into diacylglycerol with rates of 40 nm min−1g−1FW at 20 μM oleoyl‐CoA. The pH optimum was 7.5–9.0, and normal saturation kinetics were seen with oleoyl‐CoA; the S0.5was about 32 μM. Exogenous acyl acceptors, such as glycerol 3‐phosphate, lysophosphatidic acid and lysophosphatidylcholine stimulated oleate incorporation into diacylglycerol. The detergents Triton X‐100 and sodium cholate inhibited diacylglycerol formation at concentrations in the region of their critical micellar concentration, while n‐octyl‐β,D‐glyco‐pyranoside had no effect, even at high concentration. The significance of these findings for the mechanism of oil‐body formation in developing oilseeds is discussed.
Linoleic acid requirement of rats fedtrans fatty acids
Authors: Zevenbergen J. L. , Houtsmuller U. M. T. , Gottenbos J. J.
Published: November 2006

The amount of linoleic acid required to prevent undesirable effects of C18trans fatty acids was investigated. In a first experiment, six groups of rats were fed diets with a high content oftrans fatty acids (20% of energy [en%]), and increasing amounts of linoleic acid (0.4 to 7.1 en%). In a second experiment, four groups of rats were fed diets designed to comparetrans fatty acids with saturated andcis‐monounsaturated fatty acids of the same chain length at the 2 en% linoleic acid level. After 9–14 weeks, the oxygen uptake, lipid composition and ATP synthesis of heart and liver mitochondria were determined.

The phospholipid composition of the mitochondria did not change, but the fatty acid compositions of the two main mitochondrial phospholipids were influenced by the dietary fats.Trans fatty acids were incorporated in all phospholipids investigated. The linoleic acid level in the phospholipids, irrespective of the dietary content of linoleic acid, increased on incorporation oftrans fatty acids. The arachidonic acid level had decreased in most phospholipids in animals fed diets containing 2 en% linoleic acid. At higher linoleic acid intakes, the effect oftrans fatty acids on the phospholipid arachidonic acid level diminished. However, in heart mitochondrial phosphatidylethanolamine,trans fatty acids significantly increased the arachidonic acid level. Despite these changes in composition, neither the amount of dietary linoleic acid nor the addition oftrans fatty acids influenced the mitochondrial function. For rats, a level of 2 en% of linoleic acid is sufficient to prevent undesirable effects of high amounts of dietary C18trans fatty acids on the mitochondrial function.
Human placenta gangliosides
Authors: Taki Takao , Matsuo Ken‐ichi , Yamamoto Kaname , Matsubara Toshiko , Hayashi Akira , Abe Tadayuki , Matsumoto Makoto
Published: November 2006

Gangliosides extracted from human placenta were composed of four major components (G1–G4), which were purified by silica beads column chromatography. The structures of these gangliosides were analyzed by exoglycosidase treatments, 400 MHz proton magnetic resonance spectroscopy and gas chromatography‐mass spectrometry and were concluded to be as follows:

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Gangliosides containing more than 10 sugar residues were observed in addition to the above four major components. But ganglio‐series gngliosides were undetectable in the placenta.
Butter‐enriched diets reduce arterial prostacyclin production in rats
Authors: O'Dea Kerin , Steel Merryn , Naughton Joan , Sinclair Andrew , Hopkins Grant , Angus James , He Guo‐Wei , Niall Margaret , Martin T. J.
Published: November 2006

Rats were fed diets containing 10%, 30% or 50% energy as fat derived predominantly from butter or lard. The protein content of the diets was maintained at 20%. After three weeks on the diets, the rats were killed and the following parameters measured: prostacyclin production in vitro from abdominal aorta and mesenteric artery; platelet aggregation to ADP and thrombin; fatty acid composition of the phospholipids in plasma, thoracic aorta and liver; smooth muscle reactivity and release of endothelial derived relaxing factor (EDRF) from aortic endothelium stimulated by acetylcholine. There was no significant effect of increasing fat content of the diets (neither lard nor butter) on platelet aggregation. In contrast, prostacyclin production in both the mesenteric artery and the abdominal aorta fell in a concentration‐dependent manner in the butter‐supplemented rats. However, no effect on prostacyclin production was detected in arteries from the lard‐supplemented animals. The effects of the diets on prostacyclin (PGI2) production correlated very well with the changes in plasma, aortic and liver phospholipid arachidonic acid (AA) and eicosapentaenoic acid (EPA) contents. AA decreased in a concentration‐dependent manner in the rats fed the butter‐enriched diets but did not change in those fed the lard‐enriched diets, whereas EPA rose in a concentration‐dependent manner in the butter‐fed rats and was unchanged in the lard‐fed animals. The clear‐cut effects of the butter‐enriched diets on aortic phospholipid fatty acid composition and aortic PGI2 production were accompanied by a significant reduction in smooth muscle relaxation to EDRF. These results indicate that in the rat, enrichment of the diet with butter can reduce the concentration of AA and increase that of EPA in plasma and tissue phospholipids with a parallel reduction in arterial PGI2 production and EDRF.
Effects of cyclopropenoid fatty acids on fungal growth and lipid composition
Authors: Schmid Katherine M. , Patterson Glenn W.
Published: November 2006

Cyclopropenoid fatty acids (CPE) isolated fromSterculia foetida oil by urea clathration and reverse phase high performance liquid chromatography (HPLC) were introduced into fungal cultures. Stearate levels in phospholipids and triacylglycerols fromUstilago maydis sporidia rose considerably in response to 30 μM CPE. In addition, CPE themselves were incorporated into glycerolipid fractions. Sterol composition was unaffected. Changes in lipid composition were accompanied by inhibition of dry weight accumulation and sporidial number. Treated sporidia showed irregular wall deposition and a branched morphology. Oleate alleviated CPE effects on growth and morphology. Hyphal extension byRhizoctonia solani was inhibited somewhat by 30 μM sterculate, whileFusarium oxysporum showed no appreciable response. Although CPE appeared to inhibit fatty acid desaturation byF. oxysporum, gross increases in the proportion of stearate were limited to the triacylglycerol fraction during 30 μM treatments. The possibility that the CPE synthesized by plants serve as antifungal agents is discussed.
Long‐chain alkanediols: Biological markers for cyanobacterial contributions to sediments
Authors: Morris R. J. , Brassell S. C.
Published: November 2006

One significant family of sedimentary lipids of widespread occurrence are series of C28–C32 alkanediols and hydroxyketones. The recognition of the same series of alkanediols as major lipid components of a field population of the cyanobacteriumAphanizomenon flos‐aquae leads us to propose that these lipids are markers for cyanobacterial inputs to sediments. The frequency of occurrence of the alkanediols in sedimentary environments supports the recent finding that cyanobacteria are major contributors to the aquatic biomass.
Membrane lipid alteration: Effect on cellular uptake of mitoxantrone
Authors: Burns C. Patrick , Haugstad Bradley N. , Mossman Craig J. , North James A. , Ingraham Leah M.
Published: November 2006

We have studied the effect of membrane structural alteration on the cellular association of the anticancer drug mitoxantrone whose uptake is not carrier‐mediated. Membrane fatty acids of L1210 cells were modified by incubating the cells with the highly unsaturated docosahexaenoic acid (22∶6), which results in isolated plasma membranes with 37% of the fatty acids as 22∶6, or with the monounsaturated oleic acid (18∶1), which results in 58% of the fatty acids as 18∶1. The rate of uptake by 22∶6‐enriched cells during the first min was 62% greater than by those enriched with 18∶1. The higher rate was recorded at 0.5–16 μM, pH 6.6–7.6 and temperatures 10–40 C. The difference in cell‐associated drug apparently was not due simply to a change in mitoxantrone solubility as measured by partitioning of the drug in lipophilic‐hydrophilic systems containing lipids from the fatty‐acid altered cells. We conclude that the type of fatty acids contained in L1210 cell membranes can affect the cell association of mitoxantrone. This effect could be on transmembrane flux or be due to differences in binding of the drug to intracellular structures.
Hydroxyacid derivatives in human epidermis
Authors: Wertz Philip W. , Downing Donald T.
Published: November 2006

The principal objective of this investigation was to examine the ω‐hydroxyacid derivatives in the cornified layer of human skin. Toward this end, sunburn peelings were collected, and the lipids were extracted with chlofoform/methanol. Comparison with authentic standards by thin layer chromatography (TLC) indicated the presence of both N‐(ω‐acyloxy)acylsphingosine (acylceramide) and ω‐acyloxy fatty acid (acyl acid), which accounted for 1.7% and 2.0% of the total lipid, respectively, as estimated by photodensitometry of the charred chromatograms. Each of these lipids was isolated by preparative TLC, hydrolyzed, and the resulting fragments were further analyzed by TLC and by gas liquid chromatography (GLC) of appropriate derivatives. In both of these lipids, the predominant ω‐hydroxyacid proved to be the 30‐carbon saturated species (56–59% of the total), while linoleate was the major ester‐linked fatty acid. Linoleate was more abundant in the acyl acid (38.0%) than in acylceramide (21.4%). These findings represent the first demonstration of acyl acid in human skin and support the proposition that acyl acid, like the other linoleate‐rich ω‐hydroxyacid derivatives, functions as a molecular rivet in maintaining epidermal structure and fucntion.
Trifluoperazine increases fatty acid turnover in phospholipids in cultured human fibroblasts
Authors: Mazière Cecile , Mazière Jean‐Claude , Mora Liliana , Auclair Martine , Polonovski Jacques
Published: November 2006

A 24‐hr pretreatment of cultured human fibroblasts with trifluoperazine induced a marked increase in incorporation of saturated (stearic, palmitic) and unsaturated (oleic, arachidonic) fatty acids into phospholipids (1.5‐ to 2‐fold for 5.10−5 M trifluoperazine). Concomitantly, incorporation into cholesteryl esters was strongly inhibited (20% of control for 5.10−5 M trifluoperazine). The drug did not change the phospholipid composition of treated cells. The effect of trifluoperazine on oleic acid incorporation into phospholipids was time‐dependent and reached a maximum after a six‐hr preincubation with the drug. Trifluoperazine also induced an increase in the rate of chase of oleic acid from the different phospholipid classes. In vitro preincubation of cell‐free extracts with trifluoperazine resulted in activation of phospholipid acyltransferases, whereas cholesterol acyltransferase activity was decreased. The rapid effect of trifluoperazine together with its effect on a cell‐free system suggests a direct action of this amphiphilic drug on the acyltransferase activities, probably by modification of the structural organization of cellular membranes.
Disposition and metabolism of pristane in rat
Authors: Le Bon A. M. , Cravedi J. P. , Tulliez J. E.
Published: November 2006

The fate of pristane (2,6,10,14‐tetramethylpentadecane), a widespread isoprenoid hydrocarbon, has been studied in rats after a single per os administration of3H‐labeled pristane. The balance study showed an extensive fecal excretion (66%) mainly as unchanged hydrocarbon, whereas about 14% of ingested pristane was excreted in urine as pristane metabolites and tritiated water. After one wk, 8.3% of the ingested3H still was stored in the carcass, and radioactive distribution in tissues and organs showed a preferential incorporation into adipose tissue and liver. Over 75% of the radioactivity stored in the carcass was associated with pristane metabolites and tritiated water. Tissue metabolites were characterized by thin layer chromatography, gas chromatography and mass spectrometric analyses. Four metabolites were identified: pristan‐1‐ol, pristane‐2‐ol, pristanic acid and 4,8,12‐trimethyltridecanoic acid. These demonstrate that this isoprenoid hydrocarbon undergoes subterminal hydroxylation or terminal oxidation followed by the classical β‐oxidation process. Incorporation of metabolites in phospholipids and more particularly in the phosphatidylserine fraction has been observed and is discussed.