bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hepatic cholesterol synthesis from mevalonate and squalene in rats: Effect of feeding cholesterol supplemented diet during weaning and following starvation
Authors: Johnson Ronald C. , Shah Shantilal N. 
Published: November 2006

AbstractThe conversion of squalene to digitonin precipitable sterols by microsomes and soluble fractions from liver and the incorporation of mevalonate into nonsaponifiable lipids and digitonin precipitable sterols by 5000 g liver supernatant was studied in suckling rats and rats weaned on diet (Purina chow) supplemented with varying levels of cholesterol. The results indicate that the conversion of squalene to digitonin precipitable sterols was low in suckling rats and high in rats weaned on Purina chow diet. Weaning rats on 1% cholesterol supplemented diet effectively eliminated the post‐weaning increase in mevalonate incorporation into nonsaponifiable and digitonin precipitable sterols, and in the conversion of squalene to digitonin precipitable sterols. The incorporation of mevalonate into nonsaponifiable lipids and digitonin precipitable sterols, and of squalene into digitonin precipitable sterols also was studied in liver preparations from adult rats which were starved and refed control or cholesterol supplemented diet. It was observed that the conversion of squalene to digitonin precipitable sterols by liver fractions from fasted rats was low, while that by liver fractions from rats refed control diet was higher. Furthermore, the post‐fasting increase in the conversion of mevalonate to nonsaponifiable lipids and digitonin precipitable sterols and in squalene to digitonin precipitable sterols conversion essentially was eliminated by refeeding a 1% cholesterol supplemented diet. The low conversion of squalene to digitonin precipitable sterols in suckling rats, rats weaned on cholesterol supplemented diet, and adult rats that were starved, or starved and refed cholesterol supplemented diet, was due to the reduced activity of microsomal enzymes. It is concluded from this study that dietary cholesterol prevents the increase in cholesterol synthesis observed in developing and regenerating liver by suppressing the activities of one or more enzymes between mevalonate and squalene and between squalene and cholesterol.
Effect of light intensity upon lipid composition ofNitzschia closterium (Cylindrotheca fusiformis)
Authors: Orcutt David M. , Patterson Glenn W. 
Published: November 2006

AbstractTotal fatty acid, total sterol, fatty acids of specific lipid classes, and unsaturated fatty acids produced inNitzschia closterium were compared qualitatively and quantitatively as a function of changes in light intensity. Increased levels of total fatty acids were observed in cells grown at high light intensity when compared to cells grown at low light intensity. However, the percentage of unsaturated fatty acid decreased under high light conditions. Fatty acid analysis of triglyceride and 1,3 diglyceride fractions indicated an increase in levels of fatty acid at high light intensity when compared to low light intensity, while levels of polar lipid fatty acids increased at low light intensity. These analyses can be taken to indicate an increase in triglyceride and diglyceride at high light and a decrease in polar lipid at high light. Levels of free fatty acids did not differ significantly with light intensity. The levels of total sterol also were unaffected by changes in light intensity. However, levels of sterol isolated as free sterol and sterol associated in a yet unknown manner in the polar lipid fraction varied with changes in light intensity. Levels of polar lipid sterol increased at high light intensity compared to low light intensity, while the opposite was true for free sterol. The greatest percentage of total sterol was found in the polar lipid class regardless of light intensity.
Sphingophospholipids of species ofAedes andCulex mosquito cells cultivated in suspension culture from logarithmic and stationary phases of growth
Authors: Yang T. K. , Mc Means E. , Anderson L. E. , Jenkin H. M. 
Published: November 2006

AbstractTwo sphingophospholipids, sphingomyelin (ceramide phosphorylcholine), and ceramide phosphorylethanolamine, were isolated and purified from cells of four mosquito species obtained from the logarithmic and stationary phases of growth. Quantitation of the two lipids in both phases of growth from cells of each species was made. The fatty acid composition of the two lipids was compared between the cell types and the two phases of growth. There was a tendency for an increase of ceramide phosphorylcholine and a decrease of ceramide phosphorylethanolamine in the stationary phase. Longer chain fatty acids of ceramide phosphorylcholine were observed in the stationary phase than in the logarithmic phase of growth of the mosquito cells. The four species had distinctly different fatty acid patterns in the two complex lipids which might be useful for taxonomic purposes and cell identification.
Essential fatty acids in maternal diet and in rat milk phospholipids
Authors: Galli C. , Spagnuolo C. 
Published: November 2006

AbstractThe administrations of semisynthetic diets supplemented with oils and fats containing different levels of linoleic acids to lactating rats result in corresponding changes in the polyunsaturated fatty acids of triglycerides in the collected milk. Milk phospholipids show a quite different trend, polyunsaturated acids of the linoleic acid family being highest with low dietary linoleic acid supply, and vice versa, suggesting a control in the secretion of polyunsaturated fatty acids in milk.
Myocardial alterations resulting from feeding partially hydrogenated marine oils and peanut oil to rats
Authors: Ackman R. G. 
Published: November 2006

AbstractMyocardial alterations were observed in 5 groups of rats fed diets containing 20% fat for 16 weeks. The incidence was comparable to that from other studies and uniform at 6/20 in hearts from rats fed: partially hydrogenated herring oil to give dietary levels of either 16.7% or 4.6% 22∶1; partially hydrogenated redfish/flatfish oil to give 4.5% 22∶1 in the dietary fat; and peanut oil (of unknown origin) containing 0.1% 22∶1. The incidence was 9/20 in the hearts of rats fed an unrefined and unprocessed redfish oil at a dietary level of 16.0% 22∶1 in fatty acids.
Plasma, apolipoprotein A‐I and A‐II levels in hyperlipidemia
Authors: Schonfeld Gustav , Bailey Alberta , Steelman Robert 
Published: November 2006

AbstractSome of the component moieties of high denisty lipoproteins (HDL) were analyzed in normal subjects and in patients with hyperlipidemia. Apoproteins A‐I and A‐II were quantified by radioimmunoassay, HDL cholesterol and triglycerides were assessed on heparin‐MnCl2 supernates of fasting plasmas. We found that HDL is enriched in triglycerides in all forms of hyperlipidemia, while the proportion of ApoA‐II is unaltered and the proportion of ApoA‐I is decreased. Thus, the composition of HDL is altered in hypertriglyceridemia. The molecular associations of ApoA‐I and ApoA‐II in plasma were also examined by assaying the apoprotein contents of plasma fractions prepared by ultracentrifugation and by gel filtration column chromatography. The ApoA‐I contents of d<1.063 fraction increased in hyperlipidemia from <0.5% to ∼2%, but the ApoA‐I contents of the d>1.21 fraction remained at <12% of total in plasmas with triglyceride levels <1500 mg/dl. d>1.21 ApoA‐I rose to 23% in one plasma with a triglyceride level of >1700 mg/dl. On column chromatography, ApoA‐I eluted with the lipoproteins and also in a fraction whose molecular weight (MW) appreared to be ∼50,000 daltons. The proportion of plasma ApoA‐I which eluted in the 50,000 MW peak was positively correlated with plasma triglyceride levels, but at triglyceride levels of <1500 mg/dl, <20% of ApoA‐I was in the 50,000 MW peak. Between levels of ∼2000 and 12,000 mg/dl, the percentage “50,000 M.W. ApoA‐I” was 20–25%. The ApoA‐II contents of d<1.063 fractions were also increased in hyperlipidemia, but >95% of ApoA‐II was found in the HDL fractions in both normal and hyperlipidemic plasma both by column chromatography and ultracentrifugation. Thus, the molecular association of ApoA‐I appears to be altered in hyperlipidemia.
Bile acids in tissues: Binding of lithocholic acid to protein
Authors: Nair P. P. , Solomon Robert , Bankoski Joyce , Plapinger Robert 
Published: November 2006

AbstractHuman liver contains two forms of lithocholic acid. One form is readily extractable by 95% ethanol/0.1% ammonia (soluble lithocholate, SL), while the other remains firmly bound to the residue (tissue‐bound lithocholate, TBL). TBL could be hydrolytically released using clostridial cholanoylamino acid hydrolase, suggesting a peptide link between lithocholate and protein. With bovine serum albumin (BSA), lithocholic acid showed spontaneous amino group‐modifying activity. When small molecular weight lysine (α‐t‐BOC‐1‐lysyl‐β‐naphthylamide) and arginine peptides (α‐CBZ‐di‐arginyl‐β‐naphthylamide) were used in place of BSA, lithocholate bound specifically to the lysine peptide. The unusual affinity for lysine suggested that this amino acid might be involved as a residue in TBL. Synthesis of lithocholyl lysines and comparison with products of acid hydrolysis of TBL established ε‐lithocholyl lysine as the predominant form in which lithocholic acid is found in tissue bound form.
Fatty acid positional specificity in phospholipids of L1210 leukemia and normal mouse lymphocytes
Authors: Burns C. Patrick , Wei Shiao‐Ping L. , Luttenegger Diana G. , Spence Arthur A. 
Published: November 2006

AbstractThe positional distribution of fatty acids in the choline and ethanolamine phosphoglycerides of the L1210 murine leukemia cells was determined and compared to that of normal mouse lymphocytes. The major phospholipids of both cell types had appreciable degrees of positional specificity as evident from the higher percentage of saturated fatty acids in position 1 and of polyunsaturated fatty acids in position 2. The L1210 cells had less arachidonate and more linoleate in position 2 of choline and ethanolamine phosphoglycerides as compared to the normal lymphocytes. However, there were similar proportions of saturated, monoenoic and polyenoic fatty acids in positions 1 and 2 of the phospholipids of the L1210 leukemia cells and the lymphocytes. These data demonstrate that fatty acid positional specificity is retained in the major phospholipids of this rapidly growing tumor.
Separation of triglycerides by chain length and degree of unsaturation on silica HPLC columns
Authors: Plattner R. D. , Payne‐Wahl Kathleen 
Published: November 2006

AbstractTriacylglycerols can be separated by both chain length and number of double bonds using micro particulate silica high pressure liquid chromatography columns with isooctane, diethyl ether, and acetic acid solvent mixtures. The separations obtained are the reverse of those observed with μ‐Bondapak C18 columns (Waters Associates); i.e., longer chain length triglycerides elute from the column earlier than their shorter chain homologs, and saturated triglycerides elute before the more unsaturated ones. Base line separation was obtained between tristearin, triolein, trilinolein, and trilinolenin.
Membrane‐bound phospholipid desaturases
Authors: Pugh E. L. , Kates M. 
Published: November 2006

AbstractThis review covers studies on membrane‐bound phospholipid desaturases in yeast and rat liver carried out in this laboratory. In yeast the desaturase system was shown to effect the direct desaturation of dioleoyl‐lecithin to dilinoleoyl‐lecithin. In rat liver the desaturase was capable of converting 2‐eicosatrienoyl‐lecithin to 2‐arachidonoyl‐lecithin. Both systems required reduced pyridine nucleotides, O2 and cytochrome b5. Eicosatrienoyl‐lecithin desaturase along with eicosatrienoyl‐CoA desaturase of rat liver microsomes was solubilized with detergents and purified 7–8‐fold from the microsomal pellets. Both activities were reconstituted in the presence of deoxycholate on addition of the other components of the cytochrome b5‐electron transport chain (cytochrome b5 and NADH‐cytochrome b5 reductase) to the solubilized desaturase; addition of lecithin further stimulated the activities. The demonstration of desaturation of eicosatrienoyl‐lecithin by a solubilized and partially purified desaturase provides strong evidence for the direct desaturation of the lecithin substrate without prior conversion to the acyl‐CoA thiolester.
The relationship of dietary fats to prostaglandin biosynthesis
Authors: Mathias Melvin M. , Dupont Jacqueline 
Published: November 2006

AbstractThe direct and indirect evidence that the fatty acid composition of dietary fat is involved in the regulation of prostaglandin biosynthesis was reviewed. Direct evidence included effects of essential fatty acid deficiencies and excesses on endogenous tissue levels and production rates of prostaglandins by several tissues. Indirect evidence included lipolytic, platelet aggregatory, hypertensive, inflammatory and immune responses. In general, composition of dietary fat did not affect prostaglandin biosynthesis unless a biochemical essential fatty acid deficiency was induced or the linoleate to saturated fatty acids ratio of the dietary fat was greater than 5. Most results were interpreted in light of changing fatty acid composition; however, very few direct measurements have been made.
Experimental nephrotic syndrome induced in the rat by puromycin aminonucleoside: Hepatic synthesis of neutral lipids and phospholipids from3H‐water and3H‐palmitate
Authors: Gherardi E. , Calandra S. 
Published: November 2006

AbstractExperimental nephrotic syndrome (ascites, proteinuria, hypoalbuminemia, and hyperlipidemia) was induced in male Wistar rats by seven daily subcutaneous injections of puromycin aminonucleoside (20 mg/kg). Hepatic lipogenesis from3H‐water and3H‐palmitate was investigated in nephrotic and pair fed control rats by using liver slices. Total incorporation of3H‐water into neutral lipids was higher in nephrotic than in control rats (413±124 vs. 229±46 nmoles/g/hr, p<.01). Among neutral lipids, the major increase was observed for triacylglycerols (106±26 vs. 72±21 nmoles/g/hr, p<.05), cholesteryl esters (3.7±2.1 vs. 1.4±.7 nmoles/g/hr, p<.05) and, above all, for cholesterol (123 ±48 vs. 36±18 nmoles/g/hr, p<.0025). Total incorporation of3H‐water into phospholipids as well as incorporation of3H‐water into individual phospholipids were not significantly increased. Incorporation of3H‐palmitate into neutral lipids was increased (312±84 vs. 221±28 nmoles/g/hr, p<.05). Among neutral lipids, a significant increase was observed for 1,3‐diacylglycerols (19±3 vs. 13±3 nmoles/g/hr, p<.025), triacylglycerols (228±50 vs. 163±14 nmoles/g/hr, p<.05) and cholesteryl esters (18±5 vs. 10±1 nmoles/g/hr, p<.01). Incorporation of3H‐palmitate into phospholipids was not significantly affected. The difference in hepatic lipogenesis between nephrotic and control rats was even more pronounced if the data were corrected for the total liver weight which was significantly increased in the nephrotic rats (11.3±.3 vs. 8.5±.1 g, p<.001). These findings indicate that the synthesis of neutral lipids from both3H‐water and3H‐palmitate is elevated in rat with aminonucleoside‐induced nephrotic syndrome. The possible role of the increased hepatic lipogenesis in the pathogenesis of the nephortic hyperlipidemia is discussed.
Abnormal metabolism of polyunsaturated fatty acids and phospholipids in diabetic glomeruli
Authors: Kanzaki Tetsuto , Ishikawa Yo , Morisaki Nobuhiro , Shirai Kohji , Saito Yasushi , Yoshida Sho 
Published: November 2006

AbstractStudies were done on changes in phospholipid content and fatty acid composition of phospholipids and on the role of the acylation pathway in synthesis of phospholipids in the development of abnormal fatty acid composition in the glomeruli of rats 2 and 10 mo after induction of diabetes with streptozotocin. The proportions of individual phospholipids in the glomeruli of rats were not changed 2 mo after induction of diabetes, but the proportion of phosphatidylethanolamine (PE) decreased and that of sphingomyelin increased 10 mo after induction of diabetes. In contrast, in liver the proportion of PE was increased and that of phosphatidylcholine was decreased. These results showed that changes of individual phospholipids in glomeruli were time‐dependent and tissue‐specific. Two mo after induction of diabetes, the main change in the phospholipid fatty acid composition of diabetic glomeruli was a decrease in arachidonic acid (AA); the main change in serum free fatty acids (FFA) was an increase in linoleic acid (LA) and a decrease in AA. Ten mo after induction of diabetes, the main changes in the phospholipid fatty acid composition of glomeruli were an increase in LA and a decrease in AA; the main change of the serum FFA composition was a decrease in AA. Thus, the fatty acid composition of glomerular phospholipids was not directly correlated to that of the serum in diabetic rats. Acyl‐CoA synthetase and acyltransferase activities increased in diabetic glomeruli with either AA or LA as substrate, but activity toward LA increased more at 2 mo after induction of diabetes. Acyl‐CoA synthetase activity increased in diabetic glomeruli with LA as substrate, but that did not change with AA as substrate at 10 mo after induction of diabetes. Furthermore, acyltransferase activity decreased in diabetic glomeruli with AA as substrate, although that did not change with LA as substrate at 10 mo after induction of diabetes.
Isoprenoid fatty acids from marine sponges. Are sponges selective?
Authors: Carballeira Nestor M. , Maldonado Lilliam , Porras Beatriz 
Published: November 2006

AbstractThe burrowing spongesAnthosigmella varians andSpheciospongia vesparium were found to be rich in the isoprenoid phospholipid fatty acid 4,8,12‐trimethyltridecanoic (5.2% and 23%, respectively, of the total fatty acid composition), while the burrowing spongeChondrilla nucula and the demospongeAgelas dispar contained the acid 3,7,11,15‐tetramethylhexadecanoic (13.8% and 8.6%, respectively, of the total phospholipid fatty acid composition). No other isoprenoid fatty acid was found, and the two acids described in this work did not occur concomitantly in the same sponge.
Phospholipid studies of marine organisms: 14. Ether lipids of the spongeTethya aurantia
Authors: Smith Glenn M. , Djerassi Carl 
Published: November 2006

AbstractThe novel unesterified alkyl glycerol monoethers, (2S)‐1‐(hexadecyloxy)‐2,3‐propanediol (1), (2S)‐1‐(16‐methylheptadecyloxy)‐2,3‐propanediol (2) and (2S)‐1‐(15‐methylheptadecyloxy)‐2,3‐propanediol (3) were isolated from the marine spongeTethya aurantia and were characterized by spectroscopic methods. These three saturated ethers as well as a series of alk‐1′‐enyl glycerol monoethers were also encountered in the phospholipids of the same sponge after reduction with LiAlH4. Incorporation experiments with dissociated cells ofT. aurantia indicated that [1‐14C]‐hexadecanol was incorporated into the unesterified alkyl glycerol monoethers.
Liver parenchymal cells differ from the fat‐storing cells in their lipid composition
Authors: Hendriks Henk F. J. , Brekelmans Pieter J. A. M. , Buytenhek Rien , Brouwer Adriaan , Margreet de Leeuw A. , Knook Dick L. 
Published: November 2006

AbstractThe neutral lipid and phospholipid compositions of purified sinusoidal (fat‐storing, endothelial and Kupffer) cells, parenchymal cells and liver homogenates were determined by thin layer chromatography. In addition, the retinoid content of the same purified cell populations was determined by high performance liquid chromatography. From each cell type, both a lipid droplet fraction and a pellet fraction (containing the majority of the remaining cell organelles) were prepared by differential centrifugation. Electron microscopic analysis showed that lipid droplets isolated from fat‐storing cells were larger (up to 8 μm) than those isolated from parenchymal cells (up to 2.5 μm). Moreover, the parenchymal lipid droplets seemed to be surrounded by a membranous structure, while the fat‐storing lipid droplets seemed not to be. Both fat‐storing and parenchymal cells contained high concentrations of neutral lipids, 57.9 μg and 71.0 μg/106 cells, respectively, while endothelial and Kupffer cells contained only 8.6 μg and 13.8 μg/106 cells of neutral lipids, respectively. Sixty‐five percent of fat‐storing cell lipid droplet fractions comprised esters of retinol and cholesterol. This combined ester fraction contained mainly retinyl esters. In addition, considerable quantities (20%) of triglycerides were present. Parenchymal cell lipid droplet fractions comprised triglycerides (62%) and cholesteryl esters (up to 30%). The pellet fractions prepared from all four cell types consisted mainly of cholesterol (41–67%) and free fatt acids (20–28%). The phospholipid content was much higher in parenchymal cells than in the sinusoidal liver cell types. The relative proportions of the four major phospholipid classes were comparable in all liver cell types analyzed. It is concluded that parenchymal cell lipid droplets comprised mainly triglycerides and cholesteryl esters, which is in agreement with the function of parenchymal cells in lipid metabolism. Fat‐storing cell lipid droplets consisted of retinyl esters and triglycerides, which correlates well with their function in retionid storage and metabolism.
Periodate‐induced lipid oxidation of erythrocyte membranes
Authors: Beppu Masatoshi , Kikugawa Kiyomi 
Published: November 2006

AbstractExposure of human erythrocyte ghosts to 0.2–5 mM periodate at 0 C for 15 min resulted in an increase of thiobarbituric acid‐reactive substances and fluorescent materials in the membranes. This increase was suppressed by radical scavengers, butylated hydroxytoluene and thiourea, indicating that periodate caused lipid oxidation of ghosts. A role of hemoglobin in the periodate‐induced lipid oxidation of ghosts was suggested by the fact that the oxidation was augmented by hemoglobin and inhibited by an iron chelator, desferrioxamine. Treatment of ghosts with periodate caused membrane protein cross‐linking with and without disulfide bridge. Erythrocytes were also susceptible to lipid oxidation by periodate, but only disulfide‐mediated protein cross‐linking was observed. Erythrocytes treated with neuraminidase or trypsin were less susceptible, but those treated with neuraminidase along with galactose oxidase were nearly as susceptible as untreated cells. The effect of galactose oxidase was diminished by reduction of the enzyme‐treated cells with borohydride. These results indicate that the aldehyde moieties generated by periodate at the sialyl residues or those generated by galactose oxidase at the terminal galactosyl orN‐acetyl galactosaminyl residues of the membrane glycoconjugates play a stimulating role in the periodate‐induced membrane lipid oxidation.