bluuebunny/crossref_metadata_2025_split huggingface dataset:
Uptake and interconversion of cholesterol and cholesteryl esters byPhytophthora cactorum
Authors: Elliott C. G. , Knights B. A. 
Published: November 2006

AbstractWhen cholesterol, cholesteryl palmitate and cholesteryl acetate were added individually to sterol‐free cultures ofPhytophthora cactorum, the free sterol was at first taken up more rapidly. By 24 hr, the uptake of esters and free sterol was similar. The 2 esters apparently are taken up by different mechanisms, since much acetate was found in extracts of the mycelium at early harvests, but very little palmitate. In cultures supplemented with a mixture of cholesterol and cholesteryl palmitate, the palmitate‐derived cholesterol was preferentially incorporated into the free sterol fraction of mycelial extracts. Cholesteryl palmitate and acetate were both hydrolyzed, and free cholesterol esterified by filtrates of cultures grown on sterol‐free medium. Reverse‐phase chromatography on hydroxyalkoxy‐propyl‐Sephadex resolved the sterol esters of mycelial extracts into 3 zones, the most polar comprising mainly the linolenate ester, the next linoleate, and the least polar mainly oleate. Linoleate was predominant among the first sterol esters synthesized by the mycelium whether the supplement was free sterol, palmitate or acetate. Later, oleate became predominant.
Competitive deposition oftrans‐12‐ andcis‐9‐octadecenoates into egg yolk lipids
Authors: Lanser A. C. , Emken E. A. 
Published: November 2006

AbstractThe deposition oftrans‐12‐octadecenoate‐12(13)‐3H (12t‐18∶1‐3H) was compared tocis‐9‐octadecenoate‐10‐14C (9c‐18∶1‐14C) in the major egg yolk neutral lipids and phospholipids.trans‐12‐Octadecenoate was preferentially incorporated into cholesteryl esters (CE), phosphatidylcholines (PC), and phosphatidylethanolamines (PE) but was discriminated against in triglycerides (TG). Isotopic ratios indicate that 5.9 and 5.6 times more 12t‐18∶1‐3H than 9c‐18∶1‐14C was esterified at the 1‐acyl position of PE and PC, respectively. The combined 1‐ and 3‐acyl positions of TG and the 2‐acyl position of TG, PE and PC were each preferentially esterified with 9c‐18∶1‐14C.
Lipids of dermatophytes
Authors: Khuller G. K. , Chopra A. , Bansal V. S. , Masih R. 
Published: November 2006

AbstractThis investigation deals with phosphatides and fatty acid content ofEpidermophyton floccosum, Microsporum cookie andTrichophyton mentagrophytes during different phases of growth. Total phosphatide content of these dermatophytes decreased with age, which was reflected in constituent major phosphatides. The zwitterionic and anionic phospholipids tended to maintain a constant ratio. Short chain fatty acids increased significantly with age inE. floccosum whereas these fatty acids represented a minor fraction of the total fatty acids inM. cookie andT. mentagrophytes. The ratio of saturated to unsaturated fatty acids increased 4‐fold during growth inE. floccosum, whereas this increase was marginal inM. cookie. This ratio decreased inT. mentagrophytes.
Thromboxane B2 biosynthesis and phospholipids hydrolysis in platelets from hypercholesterolemic rabbits
Authors: Kawaguchi H. , Ishibashi T. , Imai Y. 
Published: November 2006

AbstractThromboxane B2 biosynthesis from arachidonic acid was increased in platelets from hypercholesterolemic rabbits. The enzymic activity of phospholipase A2 which releases arachidonic acid, the precursor for the biosynthesis of thromboxane B2, showed hardly any change in hypercholesterolemic platelets. Phospholipase C and diglyceride lipase activities also were not changed in platelets from hypercholesterolemic rabbits. Furthermore, phospholipid concentration in platelets were not increased in this state. Thus, we conclude that the supply of precursor for thromboxane B2 biosynthesis was not increased in platelets from hypercholesterolemic rabbits as compared to controls. These results suggest that the enzyme activity of thromboxane B2 biosynthesis may be enhanced in platelets from hypercholesterolemic rabbits.
The prevention of alcoholic fatty liver using dietary supplements: Dihydroxyacetone, pyruvate and riboflavin compared to arachidonic acid in pair‐fed rats
Authors: Goheen S. C. , Pearson E. E. , Larkin E. C. , Rao G. A. 
Published: November 2006

AbstractMale Sprague‐Dawley rats were fed for 30 days a high‐fat liquid ethanol diet with dihydroxyacetone, pyruvate and riboflavin added as supplements (AMA‐). Plasma triglyceride (TG) levels were 6‐fold greater in these rats than in those fed and alcohol with without the supplements (AA‐). The liver TG content in rats fed the AMA‐diet was similar to that of rats fed a control diet (CA‐) in which alcohol was replaced with isocaloric amounts of dextrose. Livers of rats fed the AA‐ diet had 3 times more TG than controls. Alcohol ingestion also enhanced the hepatic content of cholesteryl esters (CE) and phospholipids (PL). These lipids were reduced to levels found in livers of rats fed the control diet (CA‐) when dihydroxyacetone, pyruvate and riboflavin were included in the alcohol diet. The fatty acid compositions of TG, CE and PL from livers of rats fed the AMA‐diet were similar to those of corresponding lipids from rats fed the control diet (CA‐) but differed from compositions when fed the alcohol diet (AA‐). Regardless of the diet fed, TG had the same fatty acid composition in plasma and liver. The same was true of PL fatty acid composition. However, the fatty acid composition of CE differed between liver and plasma. The major fatty acid in liver CE was 18∶1 whereas in plasma it was arachidonic acid (20∶4). Reduced fatty liver was observed in an earlier study when rats were fed ad libitum an ethanol diet containing 20∶4. In the present study, we pair‐fed the same diet and fatty liver was not reduced. Dihydroxyacetone, pyruvate and riboflavin did not prevent alcohol‐induced fatty liver when 20∶4 was included in the AMA‐diet. Our results confirm that dietary dihydroxyacetone, pyruvate and riboflavin prevent alcohol‐induced fatty liver, and show that this effect may result from increased mobilization of fat from liver.
The role of lipid peroxidation during chronic and acute exposure to ethanol as determined by pentane expiration in the rat
Authors: Litov R. E. , Gee D. L. , Downey J. E. , Tappel A. L. 
Published: November 2006

AbstractWeanling rats were fed one of 3 diets containing 0, 11 or 200 international units (IU) dl‐α‐tocopherol acetate/kg diet for 4 weeks. Following this period, the drinking water was replaced with an 18% solution of ethanol (v/v). An isocaloric D‐glucose solution was substituted for the drinking water of a control group of rats fed the vitamin‐E‐deficient diet for 4 weeks. The 4 treatment groups were maintained on the diet and drinking regimen for 20 weeks. Basal levels of expired pentane were determined at weeks 0, 1, 3, 5, 7 and 9. Chronic ethanol consumption did not influence basal pentane production during the 9‐week treatment. Basal levels of expired pentane were affected by dietary vitamin E. Rats supplemented with vitamin E had basal pentane levels less than one‐half of the level of rats fed a vitamin‐E‐deficient diet (p<0.001). After 14 weeks of treatment, the 2 groups of rats fed a vitamin‐E‐deficient diet were administered p.o. an acute dose of 6 g of ethanol/kg body wt. Pentane expired above basal levels during the following 4‐hr period correlated with the amount of hepatic triglycerides determined at the conclusion of the experiment. The etiology of ethanol toxicity is a complex and multifactorial system made up to many biological variables that influence lipid peroxidation. The appropriate choices of experimental designs and methods are important in examining the role of lipid peroxidation.
Purification of phospholipids by preparative high pressure liquid chromatography
Authors: Geurts van Kessel W. S. M. , Tieman M. , Demel R. A. 
Published: November 2006

AbstractA method is described for the purification of a number of phospholipids by preparative high performance liquid chromatography (HPLC). Purification of digalactosyl‐diglyceride from spinach and egg phosphatidylcholine, 1,2‐dioleoyl‐sn‐glycero‐3‐phosphocholine and 1,2‐dioleoyl‐sn‐glycero‐3‐phosphoethanolamine from its reaction mixture have been resolved. The lipid separation is performed on a polygosil column and the individual compounds are monitored directly by refractive index detection. Chloroform/methanol mixtures are used as eluent systems, providing a wide polarity range to separate the classes of lipids. The developed equipment can be used for columns between 10 and 50 cm long and 4 and 50 mm inner diameter. The flow rate could be varied between 1 and 100 ml/min and applied pressures between 10 and 450 bars.
Studies on biochemical effects of nitrogen dioxide: I. Lipid peroxidation as measured by ethane exhalation of rats exposed to nitrogen dioxide
Authors: Sagai M. , Ichinose T. , Oda H. , Kubota K. 
Published: November 2006

AbstractThis research was in order to follow the periodic fluctuation of lipid peroxidation by a new method in rats exposed to nitrogen dioxide. Wistar male rats were examined for lipid peroxidation as demonstrated by ethane exhalation. In rats continuously exposed to 10 ppm nitrogen dioxide for 2 weeks, the amount of ethane exhaled fluctuated in a complex manner during the exposure. Ethane exhalation decreased slightly after the first day of exposure and then increased rapidly. The maximal values were observed after the fourth day of exposure and then decreased gradually to the initial level. Furthermore, the activity of glutathione peroxidase in lungs of rats exposed to 10 ppm nitrogen dioxide varied symmetrically against the change of ethane formation. Similar changes in ethane exhalation were observed in rats exposed to the lower levels of nitrogen dioxide (0.4, 1.2 and 4.0 ppm) for 4 months. Compared to 10 ppm nitrogen dioxide exposure for 14 days, the characteristics in rats exposed to the low levels (0.4–4.0 ppm) of nitrogen dioxide were: the decline of ethane formation, the delay in alterations, and the tendency toward gradual increased during the longer period exposure.
Identification of acidic steroids in feces of monkeys fed β‐sitosterol
Authors: Kritchevsky D. , Davidson L. M. , Mosbach E. H. , Cohen B. I. 
Published: November 2006

AbstractVervet monkeys were fed a suspension of β‐sitosterol in corn oil Acidic steroids, were separated from a 4‐day pool of feces and subjected, after fraction, to gas liquid chromatography and mass spectrometry. Evidence for the presence of derivatives of 27‐carboxysitosterol, 27‐carboxysitostanol and 7‐hydroxy, 27‐carboxysitostanol is adduced.
Arachidonic acid: Occurrence in the reproductive tract of the male house cricket (Acheta domesticus) and field cricket (Gryllus spp.)
Authors: Worthington R. E. , Brady U. E. , Thean J. E. , Wilson D. M. 
Published: November 2006

AbstractReproductive tissues from male house and field crickets were investigated for the presence of arachidonic acid. Arachidonic acid was identified by retention behavior on 3 gas liquid chromatographic column systems—SE‐30, OV 225, and Silar 10C—and by gas liquid/positive ion chemical ionization mass spectrometry. Arachidonic acid constituted 0.3 and 1.2% of total fatty acids in the house and field cricket, respectively. Freeze‐dried male reproductive tissues from house and field cricket contained ca. 0.02 and 0.16% arachidonic acid and 8.2 and 8.6% total fatty acids. Other fatty acids found in reproductive tracts of both species of crickets were 16∶0, 18∶0, 18∶1, 18∶2, 20∶0, 20∶1 and 20∶3.
Antioxidants in neoplastic cells: IV. Evidence that the phenolic antioxidant A274 is 9‐(4‐hydroxyphenyl)xanthene, an artifact in tissue culture media
Authors: Arneson R. M. , Hinds J. L. , Wander J. D. 
Published: November 2006

AbstractAn extensively conjugated phenol (A274), recently shown to be present as a common trace constituent in randomly selected batches of commercial tissue culture media, was diazomethylated; the monomethyl derivative so prepared was shown to exhibit gas chromatographic and mass spectrometric properties identical to those observed for synthetically prepared 9‐(4‐methoxyphenyl)xanthene, but different from those of several isomeric compounds. The structure 9‐(4‐hydroxyphenyl)xanthene is thus proposed for A274.
Long chain polyenoic acid levels in viably sorted, highly enriched mouse testis cells
Authors: Grogan W. McLean , Farnham William F. , Szopiak Bernice A. 
Published: November 2006

AbstractTwenty‐and 22‐carbon fatty acids of the linoleic (n‐6) and linolenic (n‐3) acid families were measured in murine spermatogonia and preleptotene spermatocytes (early), pachytene primary spermatocytes (10) round spermatids (RS), condensing spermatids (CS) and Leydig cells enriched by staput velocity sedimentation at 1 G, followed by viable microflow sorting on the basis of light scatter and DNA content. 22: 5(n‐6) increased progressively from 2 to 20% of total fatty acid in the progression of germinal cell differentiation, early »10»RS»CS, but decreased in mature sperm. The precursor 20:4(n‐6) showed a roughly reciprocal relationship. 22:6(n‐3) showed no significant correlation with cell type. 22:5(n‐6) was found highest in triglycerides of later differentiation stages whereas 20:4(n‐6) and 22:6(n‐3) were found primarily in phospholipid in all cell fractions.
Incorporation of [1‐14C] acetate into fatty acids of the crustaceansDaphnia magna andCyclops strenus in relation to temperature
Authors: Farkas T. , Kariko K. , Csengeri I. 
Published: November 2006

AbstractDaphnia magna andCyclops strenus were maintained in aquaria containing sodium [1‐14C] acetate and the effect of temperature on labeling of their lipids was investigated. Incorporation of radioactivity in total lipids was slowed by a factor of 4 in cold‐exposed (5C) specimens compared to those incubated at 25 C. There was no significant difference in the distribution of label in the lipid classes of animals incubated at the two extreme temperatures. Decrease of the temperature from 25 to 5 C brought about a considerable reduction in the formation of palmitic and stearic acids and an increase in labeling of monounsaturated (18∶1) fatty acids inD. magna. Docosapolyenoic acids were absent from lipids of this crustacean.C. strenus directed a higher proportion of radioactivity into both oleic and docosahexaenoic acids upon cold exposure. In response to decrease of the temperature,D. magna formed a less unsaturated fatty acid population, as judged from dpm ratios of total saturated to total unsaturated fatty acids, thanC. strenus. Inability to form and accumulate docosapolyenoic fatty acids byD. magna might be related to their poor survival at reduced temperatures.
Application of methoxy‐bromomercuri‐adduct fractionation to the analysis of fatty acids of partially hydrogenated marine oils
Authors: Sebedio J‐L. , Ackman R. G. 
Published: November 2006

AbstractThe fatty acids of a refined and of a partially hydrogenated menhaden oil, iodine value (IV) 84.5, were separated into different classes (e.g., monoene, diene, including pentaene and hexaene) by thin layer chromatography (TLC) of their methoxy‐bromomercuri‐adducts (MBM). In the solvent system hexane: dioxane, the separation of fatty acids occurred according to the degree of unsaturation. No influence was exerted by either the geometry or the position of the ethylenic bonds. The effect of the various chain lengths (C14−C22) was to broaden the bands, but no overlap occurred among the chain lengths. A wide range of C20 unsaturated fatty acids were prepared by the hydrazine reduction of 20∶5‐Δ5,8,11,14,17. These were separated into groups as MBM adducts and identified by comparison of their experimental and calculated equivalent chain lengths (ECL) in gas liquid chromatography (GLC) on SILAR‐5CP and SILAR‐7CP columns. This confirmed that GLC did not totally separate all groups of isomers of different degrees of unsaturation. The quantitative analysis of both refined and partially hydrogenated (IV‐84.5) menhaden oils by GLC was effected by the recovery of the fatty acid methyl esters from the MBM adduct TLC bands with the addition of methyl heptadecanoate (17∶0) as an internal standard, followed by analysis of the different fractions on open‐tubular columns coated with SILAR‐5CP. For methylene‐ and nonmethylene‐interrupted unsaturated acids, 100% recovery from the MBM adducts was achieved, but in the case of the conjugated dienes the maximal recovery was 70%.
The OV 275‐packed stainless steel column intrans‐fatty acid research: A note of caution
Authors: Walker Brian L. 
Published: November 2006

AbstractGas chromatographic analysis of fatty acid methyl esters in a 6.1 m stainless steel column packed with 15% OV 275 and operated at 220 C resulted in poor recovery of polyunsaturated esters relative to their saturated or monoenoic counterparts. Relative responses of the esters declined with increasing unsaturation, were concentration‐dependent at low concentrations and changed as the column aged. Decomposition of polyunsaturated compounds in the hot stainless steel column appeared to be the major reason for their poor recovery and renders this particular column of doubtful value in analysis of complex ester mixtures.
On the mechanisms of fatty acid transformations in membranes
Authors: Gan‐Elepano Minerva , Aeberhard Ernesto , Mead James F. 
Published: November 2006

AbstractConcentrations of albumin in excess of 1% in the incubation mixture inhibited the elongation of added fatty acids and their incorporation into microsomal lipids whereas these reactions were not inhibited with endogenous microsomal membrane fatty acids. The results of these and other studies support the idea that such reactions of membrane lipid fatty acids with membrane‐bound enzymes normally occur entirely within the membrane without release of free fatty acids to equilibrate with the fatty acid pool during the process.
Endogenous lipolytic activities during autolysis of highly enriched hepatic lysosomes
Authors: Beckman Jeffrey K. , Owens Kenneth , Weglicki William B. 
Published: November 2006

AbstractHighly enriched (50‐ to 70‐fold) fractions of “native” lysosomes were isolated using continuous flow electrophoresis from livers of rats which had not been pretreated with Triton WR‐1339. Incubation of lysosomes for 30 min at pH 5.0 in the presence of 5 mM EDTA resulted in a dramatic loss in the content of fatty acids bound to triacylglycerols (137 down to 10 μmol/mg protein) and to phospholipids and an elevation in the level of unesterified fatty acid. Phosphatidylcholine, phosphatidylethanolamine and sphingomyelin concentrations decreased whereas those of lysophosphatidylethanolamine (0.8 up to 8.5% of total lipid‐P) and lysophosphatidylcholine (1.9 up to 16.7%) rose in a manner parallel to their respective, fully acylated lipids. Other phospholipids, including phosphatidylinositol, did not change in concentration during incubation. These results indicate that lysosomal phospholipase A, sphingomyelin and triacylglycerol lipase are activated by incubation at acid pH, enabling them to hydrolyze endogenous lysosomal lipids. However, lysosomal phosphatidylinositol‐directed phospholipase C is apparently unable to interact with phosphatidylinositol of the lysosomal membrane.
Identification and quantification of prostaglandin E3 in renal medullary tissue of three strains of rats fed fish oil
Authors: Ferretti Aldo , Schoene Norberta W. , Flanagan Vincent P. 
Published: November 2006

AbstractThree strains of rats were fed a fish oil diet to verify their ability to incorporate and convert dietary eicosapentaenoic acid (20∶5ω3) into trienoic prostaglandins. Our results show that such conversion indeed occurs in kidney medullae homogenates. Specifically, the presence of prostaglandin E3 (PGE3) was established by gas chromatographic‐mass spectrometric (GC‐MS) analysis. That compound was conclusively identified by comparison of fragment ions and their relative intensities with those obtained from authentic PGE3. Further evidence was provided by studying the recovery of exogenously added PGE3. The crude ethyl acetate extracts of the medullary homogenates were methylated and cleaned up by liquid‐gel chromatography with Lipidex‐5000 prior to conversion to PGB3 for GC‐MS analysis. The PGE3 was quantified by selected ion monitoring (SIM) with [3,3,4,4‐2H4PGE2 as internal standard. The levels of PGE3 were similar, about 3 ng/mg of wet tissue, in the 3 strains of rats. Identical in vivo conversion of the 20∶5ω3 fatty acid to PGE3 could not be positively established by analysis of pooled urine specimens.
Biosynthesis of (Z,Z)‐6,9‐heptacosadiene in the American cockroach
Authors: Dwyer Lawrence A. , de Renobales Mertxe , Blomquist Gary J. 
Published: November 2006

AbstractThe biosynthesis of (Z,Z)‐6,9‐heptacosadiene, the major cuticular hydrocarbon component of the American cockroach, was examined by radiotracer and13C‐nuclear magnetic resonance (NMR) techniques. Sodium [1‐14C] acetate was incorporated about equally into the saturated and diunsaturated hydrocarbons, whereas [1‐14C] linoleate preferentially labeled the C27 alkadiene and [9,10‐3H] oleate labeled the C27 alkadiene almost exclusively.13C‐NMR demonstrated that [2‐13C] acetate labeled carbons 25 and 27 but not carbon 3 of the C27 alkadiene. In addition, ozonolysis of the diene labeled from [1‐14C] acetate followed by radio‐gas liquid chromatography showed that carbons 1–6 were not labeled, whereas the fragment containing carbons 10–27 was labeled. The data presented in this paper indicate that linoleate from the diet or synthesized de novo is elongated by the addition of acetate units and is then decarboxylated.
Absence of cholesterogenesis regulation in the liver and prostate of the BIO 87.20 hamster
Authors: Schaffner Carl P. , Brill David R. , Singhal Anil K. , Bonner Daniel P. , Goldstein Neil I. , Wang Geng M. 
Published: November 2006

AbstractNormal, adult golden Syrian hamsters and the inbred stain BIO 87.20 Syrian hamsters were maintained on either control, cholesterol, candicidin or clofibrate diets for time periods of up to 4 months. The ventral prostate gland in both species was found to synthesize cholesterol at a greater rate than the liver. Also, our results show that, while hepatic cholesterol synthesis in the normal Syrian hamster is under feedback control with dietary cholesterol, hepatic cholesterol synthesis in the BIO 87.20 hamster, and prostatic cholesterol synthesis in either species, is under no such control. This apparent regulatory defect in the BIO 87.20 hamster, which results in a dramatic accumulation of cholesterol in the liver and serum, renders this animal a potentially valuable in vivo model for the study of cholesterol‐related disorders.
Production of prostaglandins in homogenates of kidney medullae and cortices of spontaneously hypertensive rats fed menhaden oil
Authors: Schoene N. W. , Ferretti A. , Fiore D. 
Published: November 2006

AbstractMenhaden oil (MO), whose polyunsaturated fatty acids consist mainly of (n−3) fatty acids, was fed to spontaneously hypertensive rats to determine the effect of (n−3) fatty acid on the in vitro production of prostaglandins produced from arachidonic acid (20∶4[n−6]). Capacity to form PGE2 and PGF2α was impaired in homogenates of kidney medullae and cortices from rats fed the MO diet compared to rats fed the control diet. The lower amounts of diene prostaglandins produced corresponded to the decrease in the amount of 20∶4 (n−6) in the tissue. Possibly changes produced in tissue lipids by dietary fatty acids affect prostaglandin production by reducing the availability of substrate in tissue lipids.