bluuebunny/crossref_metadata_2025_split huggingface dataset:
An aldehyde‐containing galactolipid from the red algaGracilariopsis lemaneiformis
Authors: Jiang Zhi D. , Gerwick William H. 
Published: November 2006

AbstractAn unprecedented aldehyde‐containing digalactosyldi‐acylglycerol (DGDAG) has been isolated from the red algaGracilariopsis lemaneiformis and structurally defined. Its structure was determined as 1‐O‐[5‐hydroxy‐12‐oxododeca‐6(E), 8(E), 10(E)‐trienoyl]‐2‐O‐palmitoyl‐3‐O‐[‐β‐D‐galactopyranosyl‐6,1‐α‐D‐galactopyranosyl]‐glycerol by nuclear magnetic resonance (NMR) spectroscopy, mass spectrometry and degradation to simple fragments. The identification of this aldehyde‐containing DGDAG fromG. lemaneiformis, in addition to our previous findings of unusual galactolipids, further indicates that this alga has unique lipoxygenase capacities.
The hypotriglyceridemic effect of eicosapentaenoic acid in rats is reflected in increased mitochondrial fatty acid oxidation followed by diminished lipogenesis
Authors: Willumsen Nina , Skorve Jon , Hexeberg Sofie , Rustan Arild C. , Berge Rolf K. 
Published: November 2006

AbstractThe effect of eicosapentaenoic acid (EPA) on fatty acid oxidation and on key enzymes of triglyceride metabolism and lipogenesis was investigated in the liver of rats. Repeated administration of EPA to normolipidemic rats resulted in a time‐dependent decrease in plasma triglycerides, phospholipids and cholesterol. The triglyceride‐lowering effect was observed after one day of feeding whereas lowering of plasma cholesterol and phospholipids was observed after five days of treatment. The triglyceride content of liver was reduced after two‐day treatment. At that time, increased mitochondrial fatty acid oxidation occurred whereas mitochondrial and microsomal glycerophosphate acyltransferase was inhibited. The phosphatidate phosphohydrolase activity was unchanged. Adenosine triphosphate:citrate lyase, acetyl‐CoA carboxylase, fatty acid synthetase and glucose‐6‐phosphate dehydrogenase were inhibited during the 15 d of EPA treatment whereas peroxisomal β‐oxidation was increased. At one day of feeding, however, when the hypotriglyceridemic effect was established, the lipogenic enzyme activities were reduced to the same extent in palmitic acid‐treated animals as in EPA‐treated rats. In cultured rat hepatocytes, the oxidation of [14C]palmitic acid to carbon dioxide and acid‐soluble products was stimulated in the presence of EPA. These results suggest that the instant hypolipidemia in rats given EPA could be explained at least in part by a sudden increase in mitochondrial fatty acid oxidation, thereby reducing the availability of fatty acids for lipid synthesis in the liver for export,e.g., in the form of very low density lipoproteins, even before EPA induced peroxisomal fatty acid oxidation, reduced triglyceride biosynthesis and diminished lipogenesis.
Plasma clerance and hepatic utilization of stearic, myristic and linoleic acids introducedvia chylomicrons in rats
Authors: Wang Shu , Koo Sung I. 
Published: November 2006

AbstractThe primary objective of the present study was to compare the rates of plasma clearance and hepatic utilization of stearic (18∶0), myristic (14∶0) and linoleic (18∶2) acids, as introducedvia chylomicrons. Lymph chylomicrons were specifically labeledin vivo with [14C]stearic and (SA), [14C]myristic acid (MA), or [14C]linoleic acid (LA) by infusing donor rats intraduodenally with the labeled fatty acids in a lipid emulsion. Following intravenous injection of recipient rats with the labeled chylomicrons, the rates of plasma clearance and incorporation of the label in triglycerides (TG), phospholipids (PL) and other lipids in the liver were compared at 5, 15 and 30 min. [14C]SA was cleared at a slightly faster rate (t1/2=7.0 min) than [14C]MA (t1/2=8.1 min) and [14C]LA (t1/2=8.0 min) (P<0.05). [14C]SA was accumulated in the liver at a significantly faster rate than [14C]MA and [14C]LA. At the peak (15 min) of hepatic uptake, 30.3% of [14C]SA, 26.2% of [14C]LA and 21.9% of [14C]MA were recovered in the liver. At 30 min, 33.5% of [14C]SA was taken up by the liver, whereas 27.8% of [14C]LA and only 15.2% of [14C]MA were removed. In the liver, the percentage of [14C]SA incorporated into PL steadily increased with time, whereas the percent‐age incorporated into TG decreased. [14C]SA was preferentially incorporated into PL at all time intervals, as compared with [14C]MA and [14C]LA. At 30 min, 38.6% of [14C]SA was found in PL, and only 5.2% of [14C]MA and 12.0% of [14C]LA were present in PL. A large proportion of hepatic [14C]MA remained unesterified (free fatty acid) throughout the 30‐min period, with a small proportion incorporated into PL and TG. Of the total liver14C radioactivity recovered at 30 min, 63.8% of [14C]MA, 48.8% of [14C]LA and 25.5% of [14C]SA were found unesterified. During 30 min, a significantly greater amount of [14C]MA (76.9%) was oxidized in both the liver and the peripheral tissue combined, compared with [14C]LA (64.7%) and [14C]SA (61.2%). A higher proportion of [14C]LA was incorporated into TG than into PL at all time intervals. No differences were noted in the relative distribution of14C in cholesterol and other lipids among the three fatty acids. Using labeled fatty acids incorporatedin vivo into chylomicrons, the present study demonstrated that SA, MA and LA are distinctly different in their metabolic behavior. During the initial 30 min after their entry into the blood, 92–95% of the fatty acids were cleared. During this early phase of metabolism, [14C]SA was preferentially utilized for liver PL synthesis, whereas [14C]LA was better incorporated into TG. [14C]MA was poorly incorporated into hepatic lipids, but was preferentially oxidized in the liver or utilized by the peripheral tissue.
Bile acid and very low density lipoprotein production by cultured hepatocytes from hypo‐ orhyperresponsive rabbits fedcholesterol
Authors: Podrez Evgeniy A. , Kosykh Vladimir A. , Lakeev Yuri V. , Kosenkov Evgeniy I. , Mambetisaeva Elvira T. , Repin Vadim S. , Sminov Vladimir N. , Miettinen Tatu A. 
Published: November 2006

AbstractTwo groups of rabbits, either hyperresponsive or hyporesponsive to dietary cholesterol, wereselected after ten weeks of cholesterol feeding (0.2 g cholesterol/kg body weight per day). Bile acids and very low density lipoprotein (VLDL) production were determined in primary hepatocyte cultures from control, hyper‐ and hyporesponsive rabbits. Free cholesterol and cholesteryl ester contents in hepatocytes of the hyperresponsive rabbits was significantly increased. In contrast, lipid composition in hepatocytes of the hyporesponders was similar to that of control cells. Cholic acid was the predominant bile acid in the culture medium of hepatocytes together with small amounts of chenodeoxycholic and deoxycholic acids. The rate of cholic acid production by hepatocytes in the hyporesponsive group was two times higher than that in the hyperresponsive group. Bile acid production by control hepatocytes was slightly higher than in the hyperresponsive group. In contrast, secretion of VLDL cholesteryl ester was significantly increased by hepatocytes of the hyperresponsive rabbits. Similar differences, in bile acid production were found between hypo‐ and hyperresponsive rabbits selected after five days of cholesterol feeding and subsequent maintenance on a low cholesterol diet for a period of one month. The results suggest that the increased rate of bile acid production could contribute to the apparent resistance of hyporesponders to the atherogenic diet.
Mouse alveolar surfactant: Characterization of subtypes prepared by differential centrifugation
Authors: Oulton M. , MacDonald J. , Janigan D. T. , Faulkner G. T. 
Published: November 2006

AbstractTo characterize the properties of alveolar surfactant susbfractions obtained from mouse lung by differential centrifugation, lavage fluid, following a preliminary centrifugation at 140 × g for 5 min to yield a cellular pellet (Pc), was sequentially cetrifuged at 10,000 ×g for 30 min, 60,000 ×g for 60 min and 100,000 ×g for 15 h; and the resultant pellets, respectively referred to as P10, P60 and P100, were harvested for electron microscopy, phospholipid analysis and surface tension measurements. Ultrastructural differences were observed, in that P10 contained large multilamellated structures which were typical of newly secreted surfactant, P100 contained small unilamellar vesicular structures, typical of catabolic end products of alveolar surfactant and P60 appeared to contain a mixture of structures present in P10 and P100 in addition to numerous, large unilamellar vesicles which were not present in either P10 or P100. Slight but significant differences were found in the phospholipid compositions of the three subfractions but not in the fatty acid composition of their phosphatidylcholine (PC) component. There were no significant differences in their disaturated PC/total PC ratios, but significant differences in their phospholipid/protein ratios. P60 had the highest proportion of phospholipid to protein. P10 and P60 demonstrated surface activity but P100 did not. Total alveolar surfactant phospholipid was evenly distributed among the three fractions. This pattern of distribution was significantly different from that observed in rabbit subfractions prepared by the same procedure. These data indicate that mouse alveolar surfactant consists of three distinct subfractions or subtypes which can be separately and quantitatively isolated by differential centrifugation. They also suggest that there may be species differences in the relative proportions of the individual subtypes present in normal adult lung.
The role of arginines in stabilizing the active open‐lid conformation ofRhizomucor miehei lipase
Authors: Holmquist Mats , Norin Martin , Hult Karl 
Published: November 2006

AbstractMolecular dynamics simulations for the lid covering the active site ofRhizomucor miehei lipase [EC 3.1.1.3] postulated that, among other interactions, Arg86 in the lid stabilized the open‐lid conformation of the protein by multiple hydrogen bonding to the protein surface. Chemical modification of arginine residues inR. miehei lipase with 1,2‐cyclohexanedione or phenylglyoxal resulted in residual activities in the hydrolysis of tributyrin of 66 and 46%, respectively. Tryptic maps of native and phenylglyoxal‐reactedR. miehei lipase showed that Arg86 was the residue modified most, when the lipase was inhibited to the greatest extent. Guanidine, a structural analog to an arginine side chain, inhibited both the natibe enzyme and the arginine‐modified enzymes, resulting in residual activities of 26% as compared to the native enzyme. The inhibition was not an effect of enzyme denaturation. The native enzyme was also inhibited by 1‐ethylguanidine, benzamidine and urea, but to a lesser degree than by guanidine. Lipases fromHumicola lanuginosa and porcine pancreas in 100 mM guanidine showed residual activities of 88 and 70%, respectively. The lipases fromCandida antarctica, C. rugosa, Pseudomonas cepacia andP. fluoresences were not inhibited by guanidine. The inhibition ofR. miehei lipase by structural analogs of the arginine side chain and after chemical modification of arginine residues suggest a role of an arginine residue in stabilizing the active open‐lid conformation of the enzyme.
Systematic analysis of glycosphingolipids in the human gastrointestinal tract: Enrichment of sulfatides with hydroxylated longer‐chain fatty acids in the gastric and duodenal mucosa
Authors: Natomi Hitomi , Saitoh Toshihito , Sugano Kentaro , Iwamori Masao , Fukayama Masahisa , Nagai Yoshitaka 
Published: November 2006

AbstractThe composition of the glycosphingolipids of the human gastrointestinal tract was studied. The major neutral glycosphingolipids were ceramide monohexosides (e.g., GalCer, GlcCer), LacCer, Gb3Cer, Gb4Cer and more polar ones with more than four sugars, whereas neither Gg3Cer nor Gg4Cer were present. The acidic glycosphingolipids consisted of sulfatides and gangliosides such as GM3, GM1, GD3 and GD1a. Also a large amount of sulfatides was found in the gastric mucosa and duodenum. The concentrations of sulfatides in the fundic mucosa, antral mucosa and duodenum amounted to 416.0, 933.8 and 682.9 nmol/g of dry weight, respectively, exceeding those in the gastric mucosa and kidney of other mammals. The major molecular species of the sulfatides were identified as I3SO3‐GalCer with hydroxylated longer‐chain fatty acids based on the analyses by gas‐liquid chromatography and negative ion fast‐atom bombardment mass spectrometry. In contrast, gangliosides in these regions showed a tendency to be lower than sulfatides, and the molar ratios of sulfatides to gangliosides were about 2.0, whereas those in other parts were less than 0.5. A high content of sulfatides in the gastric and duodenal mucosa, where mucosa is easily insulted by acid, pepsin and bile salts, may be closely related to their roles in mucosal protection.
Kinetic study of the prooxidant effect of tocopherol. Hydrogen abstraction from lipid hydroperoxides by tocopheroxyls in solution
Authors: Mukai Kazuo , Sawada Kouhei , Kohno Yasuhiro , Terao Junji 
Published: November 2006

AbstractA kinetic study of the prooxidant effect of vitamin E (tocopherol, TocH) has been carried out. The rates of hydrogen abstraction (k−1) from methyl linoleate hydroperoxide (ML‐OOH) by α‐tocopheroxyl (α‐Toc.) (1) and eight types of alkyl substituted Toc. radicals, (2–9) in benzene solution have been determined spectrophotometrically. The results show that the rate constants decrease as the total electron‐donating capacity of the alkyl substituents on the aromatic ring of Toc. increases. The k−1 value (5.0×10−1M−1s−1) obtained for α‐Toc. (1) was found to be about seven orders of magnitude lower than the k1 value (3.2×106M−1s−1) for the reaction of α‐TocH with peroxyl radical, which is well known as the usual radical‐scavenging reaction of α‐TocH. The above reaction rates (k−1) obtained were compared with those (k3) of methyl linoleate with Toc. (1–9) in benzene solution. The rates (k−1) were found to be about six times larger than those (k3) of the corresponding Toc.. The results suggest that both reactions may relate, to the prooxidant effect of α‐TocH at high concentrations in foods and oils. The effect of the phytyl side chain on the reaction rate, of Toc. in micellar dispersions has also been studied. We have measured the rate constant, k−1, for the reaction of phosphatidylcholine hydroperoxide with a Toc. radical in benzene,tert‐butanol and in Triton X‐100 micellar dispersions, and compared the observed k−1 values with the corresponding values for ML‐OOH.
The steryl ester and phospholipid fatty acids of the spongeAgelas conifera from the Colombian Caribbean
Authors: Duque Carmenza , Cepeda Nestor , Martínez Alejandro 
Published: November 2006

AbstractThe steryl ester and phospholipid fractions of the marine spongeAgelas conifera were isolated and analyzed. The fatty acyl components of the steryl ester and phospholipid fractions as determined by gas chromatography and gas chromatography/mass spectrometry were very similar and consisted of 56.8 and 62.7% of C14−C20 acids (normal; branched, especiallyiso andanteiso; and monounsaturated, particularly Δ9 and Δ11 acids) and of 43.1 and 35.5% of C24−C26 acids (Δ5,9 diunsaturated acids), respectively. The major constituent fatty acids detected were 13‐methyltetradecanoic,n‐hexadecanoic, 10‐methylhexadecanoic, 11‐octadecenoic, 12‐methyloctadecanoic, 5,9‐pentacosadienoic and 5,9‐hexacosadienoic acids. The phospholipids isolated were identified as phosphatidylcholine (37%), phosphatidylserine (34%), phosphatidylethanolamine (16%) and phosphatidylinositol (11%). The distribution of fatty acids within the phospholipid classes was also determined.
Age‐related accumulation of phosphatidylcholine hydroperoxide in cultured human diploid cells and its prevention by α‐tocopherol
Authors: Suzuki Toshihide , Miyazawa Teruo , Fujimoto Kenshiro , Otsuka Miki , Tsutsumi Masako 
Published: November 2006

AbstractThe levels of phosphatidylcholine hydroperoxide in serially cultured human fetal diploid fibroblasts at various population doubling levels were determined by high‐performance liquid chromatography combined with chemiluminescence detections. This methodology utilizes a mixture of cytochromec and luminol as post‐column hydroperoxide group specific luminescent reagents. The cellular hydroperoxide content increased with age from 0.34 to 27.72 pmol/106 cells. At the end of the cells'in vitro lifespan (51st population doubling level), the hydroperoxide content per 106 cells reached about 80 times the level found in cells of the 20th population doubling level. Supplementation of exogenous α‐tocopherol to the culture medium prevented hydroperoxide accumulation, but did not extent the lifespanin vitro. The results indicate that substantial intracellular phospholipid hydroperoxide accumulation occurred in the course of aging of human fetal liploid fibroblasts.
Occurrence of n−5 monounsaturated fatty acids in jujube pulp lipids
Authors: Yamamoto Kohei , Shibahara Akira , Sakuma Akiko , Nakayama Takao , Kajimoto Goro 
Published: November 2006

AbstractThe pulp lipids of jujube (Zizyphus jujuba var.inermis) fruit have been shown by chromatographic, spectrometric and chemical analyses to contain a series ofcis‐monoenoic fatty acids with n−5 unsaturation as major acyl moieties. The total concentration of these n−5 fatty acids, such as 14∶1n−5, 16∶1n−5 and 18∶1n−5, ranged from 22 to 54% of total fatty acids in the pulp lipids of 11 different sources. The main component of the n−5 homologues was 16∶1n−5 in all cases. Other monoenoic acids with n−7 unsaturation, namely palmitoleic (cis‐9‐hexadecenoic) acid andcis‐vaccenic (cis‐11‐octadecenoic) acid, as well as with n−9 unsaturation, namely oleic acid, were also identified. In the seed lipids of jujube fruit, none of the n−5 monoenoic acids could be detected. Thus the jujube pulp lipids are characterized by the predominance of n−5 monoenoic acid isomers.
Lyso platelet activating factor (LysoPAF) and its enantiomer. Total synthesis and carbon‐13 NMR spectroscopy
Authors: Murari M. P. , Murari R. , Parthasarathy S. , Guy C. A. , Kumar V. V. , Malewicz B. , Baumann Wolfgang J. 
Published: November 2006

AbstractDescribed is a reaction sequence for the total synthesis of lyso platelet activating factor (lysoPAF; 1‐O‐alkyl‐sn‐glycero‐3‐phosphocholine) and its enantiomer. The procedure is versatile and yields optically pure isomers of defined chain length. The synthesis is equally suited for the preparation of lysoPAF analogues and its enantiomers with unsaturation in the long aliphatic chain. First,rac‐1(3)‐O‐alkylglycerol is prepared by alkylation ofrac‐isopropylideneglycerol with alkyl methanesulfonate followed by acid‐catalyzed removal of the ketal group. The primary hydroxy group of alkylglycerol is then protected by tritylation, the secondary hydroxy group is acylated, and the protective trityl group is removed under mild acidic conditions with boric acid on silicic acid, essentially without acyl migration. Condensation of the diradylglycerol with bromoethyl dichlorophosphate in diethyl ether, hydrolysis of the resulting chloride, and nucleophilic displacement of the bromine with trimethylamine givesrac‐1‐O‐alkyl‐2‐acylglycero‐3‐phosphocholine in good overall yield. The racemic alkylacylglycerophosphocholine is finally treated with snake venom phospholipase A2 (Ophiophagus hannah) which affords 1‐O‐alkyl‐sn‐glycero‐3‐phosphocholine (lysoPAF) of natural configuration in optically pure form. The “unnatural” 3‐O‐alkyl‐2‐O‐acyl‐sn‐glycerol‐1‐phosphocholine enantiomer, which is not susceptible to phospholipase A2 cleavage, gives 3‐O‐alkyl‐sn‐glycero‐1‐phosphocholine upon deacylation with methanolic sodium hydroxide. Homogeneity and structure of the intermediates and final products were ascertained by carbon‐13 nuclear magnetic resonance spectroscopy on monomeric solutions.
Effects of free fatty acids on the binding of steroid hormones to bovine serum albumin
Authors: Watanabe Sadao , Tani Takayuki , Watanabe Shigenobu , Senō Manabu 
Published: November 2006

AbstractThe effects of binding of free fatty acids (FFA) to bovine serum albumin (BSA) on steroid hormone binding to BSA were examined. The FFA studied included myristic, palmitic, stearic, oleic and linoleic acids. The binding coefficient K was estimated from the changes in the equilibrium partition coefficient between the aqueous and the hexane phase caused by the addition to BSA to the aqueous phase. A noticeable effect of FFA binding (molar ratio FFA/BSA, 2∶1) on the affinities of α‐estradiol, ethynylestradiol and dehydroisoandrosterone to BSA was not observed: however, the affinities of progesterone, androsterone and testosterone were distinctly enhanced by FFA binding. Furthermore, the elution profiles of gel filtration chromatography clearly showed that progesterone and testosterone are easily liberated from the hormone/BSA complexes and that stronger binding of these hormones to BSA is caused by binding of FFA to BSA. The affinity of ethynylestradiol to BSA is stronger than that of progesterone and testosterone and is not affected by palmitic acid binding to BSA.
Erythrocyte membrane lipid alterations in undernourished cerebral palsied children during high intakes of a soy oil‐based enteral formula
Authors: Harper Mary Ellen , Patrick John , Kramer John K. G. , Wolynetz Mark S. 
Published: November 2006

AbstractFive undernourished children with severe cerebral palsy (CP) were tube‐fed sufficient volumes of IsocalTM to allow rapid weight gain. IsocalTM provided, on average, 88% of their daily energy intake for at least 25 days. The purpose of our study was to correct the undernutrition and to analyze the major erythrocyte phospholipids before and after feeding periods for possible feeding and disease‐related differences. The fatty acid profiles of erythrocyte membranes from CP children were compared with those from 12 healthy children and with the fatty acid composition of the formula. There were no clinical or biochemical indications of essential fatty acid deficiency. The feeding of a soy oil‐based formula increased the proportions of 18∶2n−6 in the phospholipids. The increases occurred predominantly in phosphatidylcholine followed by phosphatidylethanolamine. Despite such large dietary intakes of soy oil, no changes were observed in the phospholipid concentrations of 20∶4n−6, 18∶3n−3, 20∶5n−3, or in the C22n−6 and C22n−3 fatty acids. These findings are consistent with an inhibition of the Δ6 desaturase by high dietary linoleate.
Selective reduction of fatty acid oxidation in colonocytes: Correlation with ulcerative colitis
Authors: Roediger W. E. W. , Nance S. 
Published: November 2006

AbstractAttempts were made to define which fatty acid (2∶0 to 18∶1) was optimally oxidized by isolated colonocytes (colonic epithelial cells) and to select inhibitors of fatty acid oxidation which would be analogous in their action to the inhibition of fatty acid oxidation observed in colonocytes involved with ulcerative colitis. Isolated colonic epithelial cells of Sprague‐Dawley rats were used with 2‐mercaptoacetate, dichloroacetate, 3‐mercaptopropionate, 4‐mercaptobutyrate, 4‐sulfatebutyrate, 2‐bromobutyrate, sulfite ions and nitrite ions. n‐Butyrate (4∶0) was maximmaly oxidized to CO2 and ketone bodies (mean value 5.46 μmol/min/g dry wt). Oxidation of butyrate to CO2 was diminished by 2‐bromobutyrate, sulfite ions and all mercapto fatty acids. Both fatty acid oxidation and glucose oxidation were significantly inhibited by 2‐bromobutyrate, while mercapto fatty acids and sulfite inhibited fatty acid oxidation (p<0.01) without significantly changing glucose oxidation. Observation with 2‐mercaptoacetate and sulfite correlate with early changes of fatty acid oxidation observed in cases of ulcerative colitis, and warrant further study with isolated colonocytes of man.