bluuebunny/crossref_metadata_2025_split huggingface dataset:
Autoxidation of phenyl linoleate and phenyl oleate: HPLC analysis of the major and minor monohydroperoxides as phenyl hydroxystearates
Authors: Haslbeck Franz , Grosch Werner 
Published: December 2006

AbstractPhenyl linoleate was oxidized under different conditions. The monohydroperoxide products were isolated and subsequently hydrogenated. The isomers of phenyl hydroxysterate obtained were separated by high pressure liquid chromatography. On the basis of cochromatography with reference materials and mass spectroscopy, it was shown that the mixture was composed mainly (96%) of phenyl 9‐hydroxy‐ and phenyl 13‐hydroxysterates (9‐ and 13‐HOPh) with 8‐, 10‐, 12‐ and 14‐HOPh as minor compounds (4%). In the minor fraction, the 8‐ and 14‐HOPh predominated in comparison to the 10‐ and 12‐HOPh. The presence of α‐tocopherol in the autoxidation experiment changed the proportion of the phenyl hydroxystearate isomers: the proportion of the 9‐ and 13‐HOPh increased and those of the 8‐ and 14‐HOPh decreased. After addition of 0.05% or higher concentrations of α‐tocopherol, the minor fraction comprised approximately equal amounts of 8‐, 10‐, 12‐ and 14‐HOPh. Autoxidation of phenyl oleate followed by hydrogenation of the monohydroperoxides resulted in the formation of a mixture of phenyl hydroxystearates containing approximately equal amounts of 8‐, 9‐, 10‐ and 11‐HOPh.
(n−3) and (n−6) polyunsaturated fatty acids in the phosphoglycerides of salt‐secreting epithelia from two marine fish species
Authors: Bell Michael V. , Simpson Catriona M. F. , Sargent John R. 
Published: December 2006

AbstractFatty acid analyses were carried out on phosphoglycerides isolated from microsomal fractions of the rectal gland of the dogfish,Scyliorthinus canicula, and gills of the cod,Gadus morhua. Ratios of (n−3)/(n−6) polyunsaturated fatty acids were ca. 10 for phosphatidylcholine, (PC), phosphatidylethanolamine (PE) and phosphatidylserine (PS) from cod gills, reflecting high concentrations of 20∶5 (n−3) and 22∶6(n−3). The ratio for phosphatidylinositol (PI) from cod gills was 1.3, reflecting high concentrations of 20∶4(n−6) as well as (n−3) polyunsaturates. PC, PE and PS from rectal glands all had much lower (n−3)/(n−6) ratios than in cod gills, reflecting higher concentrations of 20∶4(n−6), but the lowest ratio was again present in PI. The latter phospholipid had high concentrations of 18∶0 in both tissues. The relative constancy of the fatty acid composition of PI in the two salt‐secreting tissues and its similarity to mammalian phospholipids is considered to reflect its specialized role in biomembranes.
Lipid deterioration: β‐Carotene destruction and oxygen evolution in a system containing lactoperoxidase, hydrogen peroxide and halides
Authors: Kanner Joseph , Kinsella John E. 
Published: December 2006

AbstractA model system containing lactoperoxidase/H2O2/halide decomposed β‐carotene in a reaction greatly affected by the concentration of H2O2. The optimal concentrations of H2O2 for activation of iodide and bromide were 2 mM and 10 μM, respectively. The oxidation of chloride by a lactoperoxidase, using β‐carotene destruction as a sensitive method to determine the activity of the enzyme, is reported herein. In the presence of optimal amounts of H2O2, the rate of β‐carotene destruction increases slowly until a critical concentration of the halides, followed by a rapid increase in the rate when halide concentrations were furthere increased. A lactoperoxidase/H2O2/iodide and/or bromide system generates oxygen in the presence of high H2O2 and halide concentrations. β‐Carotene inhibited the evolution of oxygen. A possible mechanism of β‐carotene destruction and triplet unexcited oxygen evolution by a lactoperoxidase/H2O2/halide system are proposed.
Polycyclic hydrocarbon and polychlorinated biphenyl solubilization in aqueous solutions of mixed micelles
Authors: Laher J. M. , Barrowman J. A. 
Published: December 2006

AbstractTo determine the physiochemical behavior of xenobiotic hydrocarbons in simulated intestinal content, we examined the partition of 7,12‐dimethylbenzanthracene (DMBA), 3‐methyl cholanthrene (MC), benzo(a)pyrene, and a polychlorinated biphenyl compound (PCB, Aroclor 1242) between an emulsified oil phase and a mixed micellar solution. In a mixed lipid‐bile salt system, negligible amounts of hydrocarbon were present in aqueous solution below the critical micellar concentration (CMC) of sodium taurocholate. Once the CMC was obtained, the 4 hydrocarbons exhibited nearly identical partitions from the lipid into the micellar system which was enhanced by increased concentrations of bile salt, reduction of triglyceride concentration and the formation of mixed rather than pure bile salt micelles. The partition of DMBA and MC into micelles was optimized by long‐chain monounsaturated oleic acid and monooleoylglycerol as compared to their octanoic or linoleic counterparts. Linoleic acid and monolinoleoylglycerol maximized the partition of PCB from the oil into the micellar phase. In a mixed micellar system excluding an oil phase and an excess of DMBA, a molar saturation ratio (mol hydrocarbon:mol bile salt) was calculated by regression analysis to be 0.162. This indicates that more than one molecule of hydrocarbon is solubilized per mixed micelle and that the aqueous solubilization of hydrocarbon may be attributed to true micellar solubilization.
Relative contribution of the main tissues and organs to body fatty acid synthesis in the rat
Authors: Gandemer G. , Durand G. , Pascal G. 
Published: December 2006

AbstractTritiated water was used to measure the rate of fatty acid synthesis in the main tissues and organs of 7‐week old wistar male rats in order to determine the relative contribution of each tissue to body fatty acid synthesis. We reached the following conclusions: (a) the liver is the main site of fatty acid synthesis, it alone synthesizes 42% of the newly synthesized fatty acids in the body. (b) The dissectable white adipose tissues synthesize 27% of the fatty acids in the body. This group of tissues is heterogeneous because the mesenteric adipose tissue alone contains 40% of the labeled fatty acids present in the white adipose tissues. (c) Besides the intestines, organs other than the liver play a negligible role (2% of the total) in fatty acid synthesis. (d) The skin contributes 7% of the body fatty acid synthesis. (e) The rest of the carcass, essentially composed of the musculature and the skeleton, contributes 18% of body fatty acid synthesis and accounts for 33% of the extrahepatic tissue fatty acid synthesis.
Determination of lycopene, α‐ and β‐carotene and retinyl esters in human serum by reversed‐phase high performance liquid chromatography
Authors: Broich Carla R. , Gerber Leonard E. , Erdman John W. 
Published: December 2006

AbstractA rapid specific, microdetermination of the major human blood carotenoids by high performance liquid chromatography (HPLC) separation and quantitation at 466 nm is detailed in this paper. Serum retinyl esters can also be quantified utilizing the same separation procedure but detected at 325 nm. One hundred microliters of deproteinated serum were extracted with chloroform and injected on a reverse‐phase column. Separation occurred within 16 min for all compounds of interest employing a mobile solvent of MeOH/AcN/CHCl3 (47∶47∶6). All compounds were quantified at the wavelengths cited by integrated peak areas using retinyl acetate as a daily standard. Analysis of serum from a hypercarotenemic anorexia nervosa patient and a person suffering from hypervitaminosis A are presented as examples of the clinical application of this procedure.
Effect of antioxidants on the photooxidation of fatty acids
Authors: Logani M. K. , Shah B. , Davies R. E. 
Published: December 2006

AbstractThe effect of butylated hydroxytoluene (BHT), butylated hydroxy anisole (BHA) and tocopherol acetate on photooxidation of the fatty acids was studied. A marked increase in the photooxidation was observed in the presence of BHT, and this effect was further potentiated by hexabromobiphenyls. Conversely, BHA and tocopherol acetate as such did not show any significant effect, but greatly enhanced the photooxidation when hexabromobiphenyls were also present. Hexabromobiphenyls by themselves did not show any notable effect on the photooxidation.
Desmosterol in human milk
Authors: Clark Richard M. , Fey Mark B. , Jensen Robert G. , Hill Dennis W. 
Published: December 2006

AbstractMilk samples were collected from mothers at 2,6, 12 and 16 weeks postpartum. Desmosterol was found to be present in all the milk samples. Identification of desmosterol was based on retention times with two gas liquid chromatography (GLC) columns and verified by GC‐m ass spectrometry. The concentration of desmosterol in breast milk increased significantly (P<0.5) from 0.6 mg/100 ml at 2 weeks to 1.3 mg/100 ml at 16 weeks postpartum. Desmosterol was not significantly correlated with total lipid, total cholesterol or free cholesterol in the milk.
Double‐bond location in long‐chain polyunsaturated fatty acids by chemical lonization‐mass spectrometry
Authors: Lankelma Jan , Ayanoglu Eser , Djerassi Carl 
Published: December 2006

AbstractFor determination of the double‐bond position in polyunsaturated C24–30 fatty acids from marine organisms, methoxy derivatives were prepared. Diagnostic mass spectral fragment as well as molecular ion intensities were obtained by adjusting the ion source optics in the presence of ammonia at a lower source pressure than used conventionally. A lower detection limit was observed compared to conventional methane chemical ionization, which is a more favorable condition for capillary gas chromatography. Analysis of fatty acids from the spongeCalyx niceaensis showed the double‐bond position of 8 unsaturated fatty acids, including two new ones. In addition, structural proof is provided for the presence of a new cyclopropane‐containing fatty acid: 19,20‐methylene‐hexacosanoic acid.
Stereospecific analysis of triglycerides ofGlycine max, Glycine soya, Avena sativa andAvena sterilis strains
Authors: Pan W. P. , Hammond E. G. 
Published: December 2006

AbstractA rapid method for the stereospecific analysis of triglycerides based on enzymatic hydrolysis on thin layer plates was applied to a number ofGlycine max, Glycine soya, Avena sativa andAvena sterilis strains. The percentage of each fatty acid on thesn‐1,sn‐2‐ andsn‐3‐positions was linearly related to the total percentage of the fatty acid in the triglyceride. Large deviations from the common triglyceride pattern were not found.
Ceramides from the spongeDysidea etheria
Authors: Grode Stephen H. , Cardellina John H. 
Published: December 2006

AbstractCeramides have been isolated from the polar organic extracts of the spongeDysidea etheria. The ceramides proved to be amides of sphingosine with either normal, saturated fatty acids or saturated α‐hydroxy fatty acids. Sphingosine was identified by isolation from the hydrolysis reaction mixture, acetylation and comparison of its physical and spectral properties with those reported for authentic sphingosine triacetate. The acids were identified by gas chromatography‐mass spectrometry analysis of their respective methyl esters.
Occurrence of long‐chain alkan‐diols and alkan‐15‐one‐1‐ols in a quaternary sapropel from the Eastern Mediterranean
Authors: Smith Dedric J. , Eglinton Geoffrey , Morris Robert J. 
Published: December 2006

AbstractC28−C32 alkandiols and keto‐ols are reported in an S1 sapropel from the Eastern Mediterranean. Mediterranean. Their occurrence in this sediment and in certain other sedimentary environments may provide a clue to their source which is thought to be a specific marine organism or group of marine organisms.
Characteristics of the formation of the platelet lipoxygenase product from endogenous arachidonic acid
Authors: Hwang Daniel H. 
Published: December 2006

AbstractThe concentration of 12‐hydroxyeicosatetraenoic acid (12‐HETE) formed in rat platelets aggregated by collagen suspension increased continuously during a 115‐min incubation period, whereas the concentration of TXB2 or PGF2α reached the maximum within 3 min and stayed at the plateau for the remaining incubation period. These data indicate that platelet lipoxygenase is not completely inactivated as is cyclooxygenase by the oxidizing agent. Platelets of essential fatty acid deficient (EFAD) rats resuspended in plasma of control rats produced more 12‐HETE than platelet‐rich plasma (PRP) of EFAD rats, whereas platelets of control rats resuspended in plasma of EFAD rats formed less 12‐HETE than PRP of control rats. However, the concentration of TXB2 or PGF2α produced was not changed in both cases implying that platelet cyclooxygenase preferentially utilizes arachidonic acid (AA) derived from platelet lipids. Radioactivity of phosphatidylcholine (2‐arachidonyl‐1‐14C) suspended in the plasma of PRP was incorporated into 12‐HETE but not to TXB2, indicating again that only lipoxygenase can utilize AA derived from plasma phospholipids. The significance of this observation is that the effects of platelet lipoxygenase products, although their physiological roles are not known, would be much more persistent than cyclooxygenase products after platelets are stimulated or aggregated in vivo.
Phosphatidate phosphatase of dermatophytes
Authors: Kasinathan C. , Chopra A. , Khuller G. K. 
Published: December 2006

AbstractPhosphatidate phosphatase (EC 3.1.3.4) was detected in filamentous pathogenic fungi. In both dermatophytes,Microsporum gypseum andEpidermophyton floccosum, the enzyme was located in the mitochondrial and microsomal subcellular fractions with a pH optimum of 6.0. TheE. floccosum enzyme was more active than that ofM. gypseum. Although the enzyme in both fractions of the dermatophytes was susceptible to inhibition by Fe2+, Mn2+, Cu2+, Ba2+ and Hg2+, theE. floccosum microsomal enzyme was completely inhibited by Mn2+ and Fe2+. The enzyme ofM. gypseum as well as ofE. floccosum exhibited a Mg2+ dependency in presence of EDTA. Sulphydryl reagents did not inhibit either the mitochondrial or the microsomal enzyme of these fungi. Phosphorylcholine and lysophosphatidylcholine markedly inhibited the enzyme in the two dermatophytes; however, the inhibition was less pronounced with phosphatidylcholine.
Fatty acid specificity in the inhibition of cell proliferation and its relationship to lipid peroxidation and prostaglandin biosynthesis
Authors: Morisaki N. , Sprecher H. , Milo G. E. , Cornwell D. G. 
Published: December 2006

AbstractPrimary cultures of smooth muscle cells were established from the medial layer of guinea pig aorta. Cells at passage level 4 were treated with different series of fatty acids belonging to the n‐9, n‐6 and n‐3 families. Lipid peroxidation was measured by the thiobarbituric acid assay and prostaglandin biosynthesis was measured by the radioimmunoassay of PGE and 6‐keto‐PGF1α. Cell proliferation was estimated from the total cell number of cultures seeded at low density. 18∶1(n‐9) did not form lipid peroxides and this fatty acid stimulated cell proliferation. All fatty acids which generated lipid peroxides inhibited cell proliferation, but inhibition was correlated with the degree of lipid peroxidation only in the n‐9 fatty acid family. 22∶4(n‐6) and 22∶6(n‐3) inhibited prostaglandin biosynthesis. 18∶2(n‐6), 18∶2(n‐9), 18∶3(n‐3), 20∶2(n‐9), 20∶3(n‐3) and 20∶5(n‐3) had no effect on prostaglandin biosynthesis. 18∶3(n‐6), 20∶3(n‐6) and 20∶4(n‐6) generated prostaglandins. 20∶3(n‐9) generated metabolites with prostaglandin immunoreactivity. The inhibition of cell proliferation did not correlate with enhanced or inhibited prostaglandin synthesis. The inhibition of cell proliferation was related to the structures of the different polyunsaturated fatty acid families decreasing in the order n‐9>n‐6>n‐3. Eicosatrienoic acids were the most effective inhibitors of cell proliferation in each fatty acid family and 20∶3(n‐9) was the most potent eicosatrienoic acid. These data show that specific as yet unrecognized products of fatty acid metabolism are responsible for the inhibition of cell proliferation.
Fatty acid and phospholipid composition ofBacillus megaterium spores with altered germination properties
Authors: Skomurski J. F. , Vary J. C. 
Published: December 2006

AbstractThe ability of spores to trigger germination was altered by growing spores at either a suboptimal temperature or in a rich medium modified by substituting L‐isoleucine for D‐glucose. Compared to the control, spores grown in the presence of isoleucine germinated more readily between 20 and 28 C, while spores grown at 20 C germinated slower than the control at any temperature tested. Analysis of the composition of these spores indicated that spores grown in the presence of isoleucine had much higher levels of anteiso‐C15 fatty acids than the control, while the phospholipid composition and the phospholipid to protein ratio were unchanged. The fatty acid composition for spores grown at 20 C was comparable to that of the control spores, but the levels of diphosphatidylglycerol and phosphatidylglycerol were altered as well as the ratio of phospholipid to protein. Steady‐state fluorescent anisotropy measurements were made with 1,6‐diphenyl‐1,3,5‐hexatriene incorporated into membrane isolated from these spores. The membranes from spores grown in the presence of isoleucine were more “fluid” between 10 and 20 C than membranes from the control spores. Membranes from 20 C grown spores were less “fluid” between 10 and 38 C than membranes from the control spores. These results show that triggering of spore germination was altered by growing spores under conditions that altered the composition of spore membranes.
Nonspecific lipid transfer proteins as probes of membrane structure and function
Authors: Crain Richard C. 
Published: December 2006

AbstractA protein that accelerates transfer of phospholipids of varying head group and fatty acid composition has been purified from bovine liver. As previously found for other phospholipid transfer proteins, “nonspecific lipid transfer protein” stimulates a kinetically biphasic transfer of radioactively labeled phospholipid from small unilamellar vesicles to unlabeled multilamellar vesicles. The kinetics are consistent with rapid transfer of phospholipid from the outer monalyer and slow transfer of that localized in the inner monolayer (half‐times greater than 3 days for phosphatidylcholine, phosphatidylethanolamine, and phosphatidylinositol). Protein catalyzed transfer is inhibited by high ionic strength and has an activation energy of 35 kJ/mol. The broad lipid specificity and ease of large‐scale purification make these proteins candidates for membrane phospholipid compositional modification. The compositions of rat liver mitochondrial and microsomal membranes and Morris hepatoma 7288c mitochondrial membranes were altered by incubation with lipid vesicles and nonspecific lipid transfer protein. Incubation with phosphatidylcholine vesicles led to increased levels of phosphatidylcholine and decreased levels of other transferrable lipids (phosphatidylethanolamine, phosphatidylinositol, and cholesterol) unless the latter were included in the vesicles. When vesicles containing dipalmitoylphosphatidylcholine were incubated with microsomal membranes, a large increase in disaturated phosphatidylcholine was also observed. These changes in composition were correlated with activities of membrane enzymes. It appears that microsomal glucose‐6‐phosphatase is inhibited by increased phosphatidylcholine saturation. Moreover, this enzyme is also inhibited by decreases in the phosphatidylethanolamine/phosphatidylcholine ratio whereas NADPH cytochrome c reductase is not. Likewise, decreased cholesterol to phospholipid ratios did not greatly affect the abnormally low levels of hepatoma succinate cytochrome c reductase activity.
Changes in the activities of lipoprotein lipase and the lipogenic enzymes in tumor‐bearing rats
Authors: Lanza‐Jacoby Susan , Miller Elizabeth E. , Rosato Francis E. 
Published: December 2006

AbstractThe effects of tumor growth on lipid metabolism were investigated by evaluating serum lipids, lipoprotein lipase activity (LPLA), the lipogenic enzymes, urinary catecholamines along with serum insulin and glucagon levels. We injected 1.5×106 cells of rat mammary tumor, AC33, and killed the rats on the 18th day. Serum triglycerides and free fatty acids of the tumor‐bearing (TB) rats increased 4 and 5 times, respectively, more than the control (C) rats. Total liver lipids were not significantly different between the two groups. Tumor growth produced a 70% decrease in total epididymal fat pad LPLA; there were no changes in soleus muscle LPLA. Serum insulin levels of the TB rats were 49% less than the C rats. The TB rats had significantly lighter epididymal fat pads and lower activities of adipose fatty acid synthetase and citrate cleavage enzyme. Urinary catecholamines of the TB rats were reduced over 30% compared with the C rats. These results show that the hypertriglyceridemia of the TB rats may be due, in part, to a deficiency of adipose tissue LPLA. The data also suggest that the effects of the tumor on lipid metabolism may be mediated through insulin.
Effects of different fractions of the barley kernel on the hepatic lipid metabolism of chickens,
Authors: Burger Warren C. , Qureshi Asaf A. , Prentice Neville , Elson Charles E. 
Published: December 2006

AbstractVarious physical fractions of the barley kernel were fed to one‐day‐old female and male chickens to determine their effect on hepatic β‐hydroxy‐β‐methylglutaryl coenzyme A (HMG‐CoA) reductase, cholesterol 7α‐hydroxylase and the lipogenic enzymes, acetyl‐CoA carboxylase (ACX), malic enzyme (ME), citrate‐cleavage enzyme (CCE) and fatty acid synthetase (FAS) at the subcellular level. Significant inhibition (p<0.01) of cholesterol biosynthesis accompanied by significant decreases in plasma cholesterol concentrations and induction of fatty acid synthesis were found in diets based on pearled barley, barley pearlings and a high‐protein barley flour (HPBF: aleurone and subaleurone layers of barley endosperm) separated from the pearlings when compared to corn. Lower weight gains in 1‐ to 4‐week‐old birds fed the high‐protein barley flour were found to be the result of lower feed consumption; pair feeding of 12‐week‐old birds with diets based on corn and high‐protein barley flour produced equal weight gains in both treatments and significant reductions in hepatic HMG‐CoA reductase, plasma cholesterol and induction in several lipogenic enzymes in birds fed the high‐protein barley flour. Substitutions of 5–20% high‐protein barley flour for corn in a corn‐based diet produced significant weight gains (p<0.01) of 10 to 20% in 2‐week‐old chickens, inhibited cholesterol biosynthesis by 45–65% and produced a 3‐fold increase in a fatty acid synthetase. The results indicate that HPBF contains an inhibitor(s) of cholesterol biosynthesis and a growth factor(s) when compared to a corn‐based diet.