bluuebunny/crossref_metadata_2025_split huggingface dataset:
Norflurazon—An inhibitor of essential fatty acid desaturation in isolated liver cells
Authors: Hagve Tor‐Arne , Christophersen Bjørn O. , Boger Peter 
Published: November 2006

AbstractNorflurazon is a herbicide known to inhibit carotene biosynthesis and linolenic acid biosynthesis in plants. In the present work, the effect of norflurazon on the metabolism of essential fatty acids was studied in isolated rat liver cells and in rat liver microsomes, incubated with [1‐14C] labeled linolenic acid (18∶3, n−3), dihomogammalinolenic acid (20∶3, n−6) and eicosapentaenoic acid (20∶5, n−3). Norflurazon (0.1 mM, 1.0 mM) was found to inhibit essential fatty acid desaturation. The Δ6 desaturation is inhibited more efficiently than the Δ5 and Δ4 desaturation. The chain elongation of essential C18 fatty acids to their C20 and C22 homoglogs was not inhibited by norflurazon.
Enhancement of eicosaenoic acid lipoxygenation in human platelets by 12‐hydroperoxy derivative of arachidonic acid
Authors: Croset Martine , Lagarde Michel 
Published: November 2006

AbstractHuman platelet lipoxygenase activity toward several eicosaenoic acids was measured in intact cells as well as in subcellular fractions (cytosol and membranes). In whole platelets, the lipoxygenation of eicosaenoic acids was enhanced greatly by high concentrations of aspirin, which partially inhibit the peroxidase activity associated with the pathway. The lipoxygenation also was increased by arachidonic acid (AA) or its lipoxygenase product, 12‐hydroxyperoxy‐eicosatetraenoic acid (12‐HPETE). Similarly, prostanoid precursors, dihomogammalinolenic (DHLA) and eicosapentaenoic (EPA) acids also were better converted by cyclooxygenase in the presence of AA or 12‐HPETE. Among the eicosaenoic acids tested, EPA oxygenation was affected most.Using cytosol or membranes as the lipoxygenase source instead of whole cells led to completely different results. AA exerted a competitive inhibition upon the other eicosaenoic acid oxygenation except that of EPA, for which a dual effect of AA was observed. This makes questionable the use of platelet subfractions for investigating lipoxygenase activity.We conclude that platelet lipoxygenation of eicosaenoic acids appears peroxide‐dependent, especially for apparent poor substrates like EPA. This might be relevant in respect to 12‐HPETE, which is the main hydroperoxy derivative to be produced during platelet activation.
Non‐soluble dietary fiber effects on lipid absorption and blood serum lipid patterns
Authors: Kies Constance 
Published: November 2006

AbstractGeneralized effects of dietary fiber on lipid absorption and blood serum lipid patterns of humans have not been defined and may not even exist. The term dietary fiber covers a wide variety of materials with different chemical and physical characteristics. The ability of pectins and mucilages, often classed as soluble fibers, to lower blood and liver lipids has been demonstrated repeatedly and consistently. However, demonstrated hypolipidemic effects of feeding such non‐soluble fibers as cellulose, hemicellulose and bran are by no means consistent. On the basis of pooled data, it appears that hypolipidemic response or non‐response of humans to inclusion of non‐soluble fibers in diets is in part related to the degree of fecal bulking as a result of in vitro water holding capacity and in part related to pre‐study blood serum lipid levels of the individual subjects.
Effect of moderate to very low fat defined formula diets on serum lipids in healthy subjects
Authors: Snook Jean T. , DeLany James P. , Vivian Virginia M. 
Published: November 2006

AbstractSerum total cholesterol, high density lipoprotein (HDL) cholesterol, and triglyceride levels were studied in healthy male and female subjects consuming for one‐week periods a diet of conventional food (CF) providing 42% of energy as fat, principally butter fat, and then in random order nutritionally complete, defined formula diets of moderate (32%) to very low (1%) fat content. Compared to CF, the formula with 32% of energy as corn oil lowered serum cholesterol by 25% and the ratio of total to HDL‐cholesterol by 13%. Low (9%) and very low (1–3%) fat formulas reduced HDL‐cholesterol by as much as 40%, raised the total: HDL‐cholesterol ratio by about 20% and raised serum triglyceride levels by as much as 100%. When low and very low fat formulas were ingested for three weeks, these effects persisted although maximal responses occurred during the first week. These results demonstrated that a moderate fat formula diet with a high P/S ratio had a more favorable effect on serum lipid levels than various low fat formulas. Low fat conventional food diets should be studied in long‐term controlled metabolic experiments before such diets are recommended to the general population for coronary heart disease or cancer prevention.
Cutin acids: Synthesis and mass spectrometry of methyl 16‐hydroxy‐7‐oxo‐, 16‐hydroxy‐8‐oxo‐, 16‐hydroxy‐9‐oxo‐, 16‐hydroxy‐10‐oxo‐ and 7,16‐, 8,16‐, 9,16‐ and 10,16‐dihydroxyhexadecanoates
Authors: Tulloch A. P. 
Published: November 2006

AbstractMethyl esters of 8 16‐carbon acids which occur in cutin of plants have been synthesized from methyl 16,17‐dihydroxy‐7‐oxo‐ and 16,17‐dihydroxy‐9‐oxoheptadecanoates. 16‐Hydroxy‐7‐oxo‐ and 16‐hydroxy‐9‐oxohexadecanoates were prepared by lead tetraacetate cleavage followed by sodium triacetoxyborohydride reduction; 16‐hydroxy‐8‐oxo‐ and 16‐hydroxy‐10‐oxohexadecanoates were prepared by successive ketalization, ester reduction, diol cleavage, acylation, oxidation and methanolysis. Dihydroxy esters were prepared by reduction of oxo esters with sodium borohydride. Mass spectra of TMS ethers of the esters, of pyrrolides and of TMS esters of pyrrolidides have been compared. Mass spectra of mixtures of hydroxyoxo derivatives and of dihydroxy derivatives show that correction factors are required for quantitative analysis, particularly when 7‐substituted isomers are present.
Partition of ketone bodies into cholesterol and fatty acids in vivo in different brain regions of developing rats
Authors: Yeh Yu‐Yan 
Published: November 2006

AbstractThe proportions of labeled ketone bodies and glucose incorporated into cholesterol and fatty acids in different regions of the brain in developing rats were compared. In cerebrums of 15‐ and 18‐day‐old rats, the ratios of dpm cholesterol/dpm fatty acids incorporated from [3‐14C] acetoacetate and [3‐14C] β‐hydroxybutyrate ranged from 0.4 to 0.7, or 50 to 100% higher than values obtained with [U‐14C] glucose. Much higher ratios were obtained with younger animals: from 1 to 12 days of life, the values ranged from 1.0 to 1.3 with [3‐14C] β‐hydroxybutyrate as substrate, and, from 1 to 5 days, with [3‐14C] acetoacetate, they were 1.0 or greater. During the first 12 days of life, the ratios resulting from administration of [U‐14C] glucose were 0.4–0.7. Clearly, a greater proportion of acetoacetate and β‐hydroxybutyrate was incorporated into cholesterol during the first week of life than the remaining suckling period. Like cerebrum, other brain regions (i.e., cerebellum, midbrain, brain stem and thalamus) yielded higher ratios of dpm cholesterol/dpm fatty acids from [3‐14C] β‐hydroxybutyrate during the first 12 days of life than on day 17. Brain stem was the most active region for lipid synthesis, and had the highest dpm cholesterol/dpm fatty acid ratio. Since active synthesis of cholesterol from ketone bodies during the early postnatal period coincides with a period of rapid brain growth, the results indicate that ketone bodies are more important early in the suckling period as sources of cholesterol for brain growth.
Effect of diet composition and fasting on lipogenesis in lean and polygenic obese mice
Authors: Hennig Bernhard , Sutherland Thomas M. , Mathias Melvin M. , Smith Barbara A. 
Published: November 2006

AbstractA line of mice was developed which exhibited spontaneous obesity when fed commercial laboratory ration low in fat content. Obese mice were compared to a nonobese related line to determine whether energy source in the diet would affect onset of obesity. Experimental diets‐beef tallow (38% of calories as beef fat and 2% as corn oil), corn oil (40% corn oil) or low‐fat (2% corn oil)‐were instituted ad libitum at the time of weaning. When the mice reached 6 months of age, lipogenesis was investigated by injecting intravenously3H2O and glucose‐U‐14C.3H2O and glucose‐U‐14C incorporation into fatty acids of fed mice was greater for obese than for lean mice. Fatty acid synthesis was inhibited by high‐fat diets compared to low‐fat diet in both lines. Of the 2 high‐fat diets, the corn oil diet inhibited fatty acid synthesis about twice as much as beef tallow diet. There was no line effect on tritium incorporation into cholesterol. Cholesterol synthesis from glucose‐U‐14C was greater in obese than lean mice. Diets had no effect on tritium and glucose‐U‐14C incorporation into cholesterol. Fasting reduced fatty acid synthesis in all mice, but total body fatty acid synthesis was not affected by lines or dietary treatment under fasted conditions. These data suggest that degree of lipogenesis, in part, explains obesity. A failure of inhibition of lipogenesis or an enhanced efficiency in fat deposition by feeding beef tallow compared to corn oil diet may explain the fact that lean mice fed the beef tallow diet tended to be more obese that lean mice fed corn oil or low‐fat diets.
Hormonal regulation of medium chain fatty acid synthesis by mouse mammary gland explants
Authors: Borst David W. 
Published: November 2006

AbstractExplants of pregnant mouse mammary tissue were cultured in media supplemented with various hormones. During the last few hours of culture, explants were labeled with [14C] acetate. Fatty acid synthesis by the tissue was analyzed using reverse phase thin layer chromatography, and incorporation of radioactivity into the medium chain fatty acid (MCFA) fraction was calculated as total MCFA per mg tissue fresh weight and as a percentage of the total fatty acid radioactivity (%MCFA). After 48 hr of culture, explants had an elevated %MCFA synthesis only when exposed to media containing insulin, cortisol and prolactin, confirming previous reports. Increasing doses of prolactin (maximal response at 300 mg/ml) caused a coordinate rise in both %MCFA synthesis and total MCFA synthesis per mg fresh weight. Epithelial cells isolated from explants after culture for 48 hr with insulin, cortisol and prolactin showed an elevated %MCFA synthesis compared to cells from explants cultured with insulin and cortisol alone, indicating that hormonal stimulation of mammary explants causes a change in the chain length of fatty acids synthesized by mammary epithelial cells. The specificity of the explant response to prolactin was tested with other hormones: FSH and calcitonin had no effect, whereas bovine growth hormone showed activity only at high concentration. Progesterone and 17β‐estradiol also had no effect. The analysis of MCFA synthesis provides another means of (a) assessing hormonal action upon mammary tissue, and (b) evaluating the biological activity of prolactin.
The influence of linoleic acid intake on membrane‐bound respiratory activities
Authors: Abuirmeileh N. M. , Elson C. E. 
Published: November 2006

AbstractThe fatty acid composition of subcellular membranes, like that of depot fats, can be altered by dietary manipulation. Most attention has been directed toward the effects of feeding an essentialfatty‐acid‐free diet. We chose to examine some responses generated by the feeding of a dietary fat containing a disproportionately high level of an essential fatty acid. Rats were fed diets formulated with beef tallow (BT) to provide 4% (P/S, 0.2) or safflower oil (SO) to provide 24% (P/S, 7.6) of total energy as linoleic acid. Lipids isolated from hepatic mitochondria of rats fed the SO diet contained, in relative terms, 85% more unsaturated bonds. Mitochondria isolated from livers of rats fed either diet were tightly coupled. When all aspects of oxidative metabolism examined in this report are considered, mitochondria of SO group origin exhibited greater oxidative activities but lower ADP/O ratios than did BT mitochondria. Our hypothesis is that the perturbed state of the membrane‐bound phospholipids initiates a remodeling‐response through which an intramitochondria source of ADP is generated to support state‐3 respiratory activity.
Gangliosides of bovine optic nerve
Authors: Das Salil K. , McCullough Melba S. 
Published: November 2006

AbstractGangliosides from bovine optic nerve were analyzed. The optic nerve contained 129, 98, 97, 80, 31 and 12 μg of GM1, GD1a, GD1b, GT1b, GD3 and GQ1 gangliosides, respectively, per g of tissue wet wt. These 6 gangliosides altogether contributed 97% of the total sialic acid. GM3 and GM2 gangliosides contributed the remaining 3% of total sialic acid. Stearoyl (18∶0) was the predominant acyl group (61–76%) in all gangliosides. There was a marked variation in acyl group composition between GT1 and most of the other major gangliosides except GD3. In comparison to the other gangliosides, GT1 contained a lower proportion of the stearoyl group and a higher proportion of the oleoyl, nervonoyl and the long chain acyl groups. Both GT1 and GD3 gangliosides contained proportionately higher levels of long chain acyl groups (20∶0→24∶0) than did other gangliosides. GD3 gangliosides showed 2 bands on thin layer chromatography, and the upper band was more distinct than the lower band.
Nitric‐oxide myoglobin as an inhibitor of lipid oxidation
Authors: Kanner Joseph , Ben‐Gera Itamar , Berman Shura 
Published: November 2006

AbstractThe effect of nitric‐oxide myoglobin (MbNO) on lipid oxidation was studied in linoleate and β‐carotene‐linoleate aqueous model systems and compared with that of metmyoglobin (MMb) and oxymyoglobin (MbO2) in short‐ and long‐term reactions. While MMb and MbO2had a clear prooxidative effect, MbNO, under the same conditions, acted as an antioxidant. The specific antioxidative activity of MbNO was maintained even in the presence of prooxidants such as hemeproteins. The significance of the conversion of MbO2and MMb into an antioxidant during the curing process is discussed.
Fatty acid and sterol composition of ungerminated spores of the vesicular‐arbuscular mycorrhizal fungus,Acaulospora laevis
Authors: Beilby J. P. 
Published: November 2006

AbstractThe fatty acids and sterols of ungerminated chlamydospores of the vesicular‐arbuscular (VA) endophyteAcaulospora laevis were examined by gas chromatography and mass spectrometry. The total lipid content of the spores was 45.5% of the spore dry weight. Predominant fatty acids were palmitoleic (52.5%), palmitic (25.5%) and oleic (7.4%). Minor fatty acids consisted of a range of (n−3) and (n−6) polyunsaturated acids. The occurrence of (n−3) polyunsaturated fatty acids is rare in fungi of the order Mucorales. Three sterols were identified as 24‐ethylcholesterol (79.9%), cholesterol (11.0%) and 24‐methylcholesterol (9.2%). No ergosterol was detected. Lipids of the chlamydospores ofA. laevis are compared with those ofGlomus caledonius.
Altered fatty acid desaturation and microsomal fatty acid composition in the streptozotocin diabetic rat
Authors: Faas Fred H. , Carter William J. 
Published: November 2006

AbstractStreptozotocin diabetes in the rat diminishes the synthesis of both monounsaturated and polyunsaturated fatty acids. Rat liver microsomal fatty acid composition and fatty acid desaturation were studied in the streptozotocin diabetic rat. The major alterations in fatty acid composition found in the diabetic rat were decreased proportions of palmitoleic, oleic and arachidonic acids and an increased proportion of linoleic and docosahexaeneoic acids. These findings, other than the increased docosahexaeneoic acid, probably result from the diminished liver microscomal δ9 and δ6 desaturase activities found in these animals. These changes are not due to the diminished weight gain of the diabetic animals since restricting food intake of control animals to achieve a similar weight gain failed to reproduce either the changes in fatty acid composition or the decrease in fatty acid desaturation. The increased food intake of the diabetic animal may contribute to the altered proportions of linleic and arachidonic acids since limiting food intake in diabetic animals to that of normal controls diminished the magnitude of these changes. Insulin therapy for 2 days not only reverses and overcorrects the diminished desaturase activities, but likewise reverses and overcorrects the altered fatty acid composition, with the exception of the diminished arachidonic aicd levels which are further decreased following insulin therapy. These findings strongly suggest that most of the changes in fatty acid composition in the diabetic rat are indeed caused by the diminished fatty acid desaturase activities.
Activity of myocardial lipase using natural edible oils as substrates
Authors: Vajreswari A. , Tulpule P. G. 
Published: November 2006

AbstractRat heart homogenates were tested for their lipolytic activity toward synthetic and natural substrates such as edible oils. Triolein was hydrolyzed very efficiently by myocardial lipase whereas trierucin was not cleaved by the enzyme. Among the natural substrates, safflower oil, which has the highest degree of unsaturation, was hydrolyzed to a greater extent than the other oils. Mustard oil rich in erucic acid formed a poor substrate for the myocardial lipase.
The identity of the cholesteryl esters in human milk
Authors: Clark R. M. , Ferris A. M. , Fey N. , Hundrieser K. E. , Jensen R. G. 
Published: November 2006

AbstractMilk samples were collected from 11 mothers who were at least 4 weeks postpartum. The amounts of fat and the fatty acid compositions of cholesteryl esters (CE) and triacylglycerols (TG) in the milk were determined. The mean concentration of total milk lipid was 3.01 gm/100 ml of milk±.42 SD. The major fatty acids esterified with CE and TG were 16∶0,cis 18∶1 and 18∶2. The patterns were similar except for a greater proportion ofcis 18∶1 in the CE. The majortrans fatty acid detected was the 18∶1 isomer which accounted for 4.48% of the TG fatty acids and 2.96% of the CE fatty acids.
Homeostasis of mucosal cholesterol in the small intestine of the rat
Authors: Blumer A. , Watt S. M. , Simmonds W. J. 
Published: November 2006

AbstractThis study was undertaken to investigate the capacity of the intestinal mucosa to maintain a constant cholesterol content under conditions where mucosal uptake or cholesterol transport into the lymph were manipulated. Two series of bile‐diverted unanaesthetised rats were infused intraduodenally with saline, triolein emulsified with Pluronic F68, or taurocholate with or without added tomatine. Pluronic F68 is a nontoxic detergent which promotes mucosal uptake of polar lipids but not cholesterol. Tomatine is a cholesterol‐binding saponin. One series of rats was used for measuring mucosal cholesterol content, DNA and protein after the test infusions. A second series of rats had the thoracic lymph duct cannulated but otherwise remained the same as the first series. The second series was used for measuring the effect of the different infusions on mass cholesterol output into lymph. Mucosal cholesterol content of rats that were not fed decreased with bile‐diversion and was restored with taurocholate infusion. This suggested a contribution of luminal cholesterol to the mucosal cholesterol pool. However, evidence for a contribution from the lumen was provided by only one of two groups of rats given infusions which did not promote mucosal uptake of cholesterol. First, addition of tomatine to the taurocholate infusate prevented both the increase in lymph output of cholesterol and the increased mucosal cholesterol content shown in rats given taurocholate alone. Second, in another group of rats in which mucosal uptake of cholesterol was prevented, i.e. in rats given Pluronic F68‐triolein emulsions, the increased fat absorption was accompanied by a marked increase in cholesterol output into lymph without a concomitant decrease in mucosal cholesterol content. These results would be consistent with increased mucosal synthesis of cholesterol as a possible source of endogenous cholesterol absorbed into lymph.
Serum lipids and fatty acid composition of tissues in rats on total parenteral nutrition (TPN)
Authors: Martins F. M. , Wennberg A. , Meurling S. , Kihlberg R. , Lindmark L. 
Published: November 2006

AbstractThe modulating effect of energy and exogenous triglyceride supply on serum lipids and fatty acid composition of liver, tibialis anterior muscle, subcutaneous and peri‐epididymal fat was assessed in rats using Total Parenteral Nutrition (TPN). Nutrients were infused continuously for 10 days through a central vein catheter. Four levels of fat were tested: No fat, Low fat (6% non‐protein calories), Medium fat (30%) and High fat (60%), at 2 energy levels (270 kcal and 350 kcal/kg·day). An isonitrogenous supply was given to all groups as 0.9 g N/kg·day. At the highest level of fat intake (20.4 g/kg) at the high energy level triglycerides, cholesterol and phospholipids of serum were elevated. Biochemical signs of essential fatty acid (EFA) deficiency were observed as rising levels of eicosatrienoic acid and lowered concentrations of linoleic and arachidonic acid, mostly in the liver and the muscle in the No fat groups. EFA levels were reduced significantly in the No fat and Low fat groups and more pronounced at the high energy level. In conclusion, our study suggests that when energy intake is increased the EFA status becomes more critical. It seems evident that more EFA is required in absolute values when hypercaloric diets are given.
Phospholipid studies of marine organisms: New branched fatty acids fromStrongylophora durissima
Authors: Dasgupta Amitava , Ayanoglu Eser , Djerassi Carl 
Published: November 2006

AbstractThe phospholipids of the spongeStrongylophora durissima were analyzed. The major phospholipids present were phosphatidylethanolamine (PE), phosphatidylcholine (PC), phosphatidylserine (PS), phosphatidylglycerol (PG) and phosphatidylinositol (PI). The major fatty acid components of the phospholipids consisted of short chain (C14−C19) and very long chain (C25−C30) “Demospongic” acids. Three novel branched Δ5 monounsaturated acids,Z‐19‐methyl‐5‐pentacosenoic,Z‐19‐methyl‐5‐hexacosenoic andZ‐19‐methyl‐5‐heptacosenoic acids were encountered in the sponge. The 3‐saturated counterparts of these compounds, 19‐methylpentacosanoic, 19‐methylhexacosanoic and 19‐methylheptacosanoic acids, as well as 19‐methylpentacosanoic and 20‐methyloctacosanoic acids also are hitherto undescribed acids present in the sponge. Trace amounts of 2 very long chain acids also were detected and their structures tentatively assigned as 19,21‐dimethylheptacosanoic and 20,22‐dimethyloctacosanoic acids. The distribution of these fatty acids according to phospholipid head groups also was described.