bluuebunny/crossref_metadata_2025_split huggingface dataset:
Flotation rates, molecular weights and hydrated densities of the low‐density lipoproteins
Authors: Lindgren F. T. , Jensen L. C. , Wills R. D. , Freeman N. K. 
Published: November 2006

AbstractA method involving three computer programs is described for characterizing the major component of the Sf 0–12 low‐density lipoprotein class by its Sf rate, hydrated density and molecular weight. All necessary information is obtained from a standard low and high‐density lipoprotein ultracentrifugal analysis. Moving‐boundary flotation rates are measured in 1.061 g/ml sodium chloride and 1.200 g/ml sodium bromide solutions and are corrected to flotation at zero concentration. Hydrated densities are calculated from η Fo versus ρ plots and minimum hydrated molecular weights calculated using Stokes' frictional factor, assuming spherical molecules. Preliminary application of this procedure indicates higher Sfo rates, higher molecular weights, and lower hydrated densities in females than in males. Molecular weights and standard deviations of the principal Sf 0–12 component for non‐fasting normal adult females and males were 2.36±0.16 and 2.12±0.20 millions, respectively.
Microbial hydration ofCis‐9‐alkenoic acids
Authors: Davis E. N. , Wallen L. L. , Goodwin J. C. , Rohwedder W. K. , Rhodes R. A. 
Published: November 2006

AbstractThe activity of acis‐9‐fatty acid hydratase produced by aPseudomonas sp. (NRRL B‐3266) isolated from soil was compared with that of another isolate previously reported (NRRL B‐2994). The presence of appropriate fatty acids for at least 4 hr during aerobic growth in yeast extract medium increased subsequent enzyme activity. Such cells anaerobically hydrated severalcis‐9‐alkenoic acids to 10‐hydroxy fatty acids and aerobically formed 10‐keto acids, which were partially degraded to shorter chain keto acids. Melting point, gas chromatography, infrared, mass spectrometry and optical rotatory dispersion data are given. Six fatty acids havingcis‐9‐unsaturation produced hydrated products, but several enoic acids havingtrans‐9‐unsaturation or double bonds in other than the 9 position were inactive as substrates. The (−)‐10‐hydroxypalmitic acid produced from palmitoleic acid is considered to have the D configuration. Yields of 71% crude crystalline product from 15 g of oleic acid and 53% from 11 g of palmitoleic acid were obtained in 5‐liter anaerobic fermentations with NRRL B‐3266. Methyl esters, triolein and oleyl alcohol were not hydrated.
Neutral lipid and fatty acid composition of earthworms (Lumbricus terrestris)
Authors: Cerbulis J. , Wight Taylor M. 
Published: November 2006

AbstractEarthworms (Lumbricus terrestris) were extracted with chloroform‐methanol (2∶1) and examined primarily for neutral lipids and fatty acids. TLC showed spots for sterols, hydrocarbons, free fatty acids, phospholipids and pigments but none for glycerides (tri‐, di‐ or mono). Saponification of the crude lipid extract yielded 32% fatty acids, 25% unsaponifiables and 43% unidentified. The lipid contained 3% hydrocarbon and 16% sterols. GLC of the hydrocarbons showed at least 13 components. GLC of the sterol fraction showed peaks corresponding to cholesterol (the major component), γ‐sitosterol, β‐sitosterol, stigmasterol, campesterol, and ergosterol. GLC showed that at least 38 fatty acids were present, with 18∶1, 18∶2, 18∶0, 20∶1 and 17∶0 predominanting.
Variation in plasma lipids with age and sex in a hypertriglyceridemic rat
Authors: Lenz Paul H. , Fleischman Alan I. 
Published: November 2006

AbstractA substrain of the Long Evans rat having the characteristics of a common human lipid disorder, hypertriglyceridemia, is described. These rats were found to be hypercholesterolemic, hyperphospholipidemic and normotriglyceridemic during the first month of life when feeding predominantly on the higher lipid, lower carbohydrate content of their mothers' milk. After weaning (22 days of age), when a typical higher carbohydrate and lower fat containing commercial laboratory feed was substituted for mother's milk, plasma cholesterol and phospholipid levels declined and triglyceride levels significantly increased. Electrophoretic analysis of lipoproteins revealed the presence of a pre‐β fraction and the absence of chylomicra, indicating that this rat is a type IV according to the Fredrickson classification system. Glucose tolerance curves remained elevated for a longer period of time and returned to normal more slowly in 1 year old compared to 2 month old males, indicating progressive alterations in glucose metabolism common in a Fredrickson type IV. After weaning, plasma phospholipid, cholesterol and triglyceride levels were significantly higher and body weight significantly lower in the female than in the male. Studies on hematocrit and hemoglobin variations with respect to age in both sexes indicated that the observed plasma lipid changes could not be attributed to hemoconcentration.
Regulation of hepatic carbohydrate metabolism by FFA and acetyl‐CoA: Sequential feedback inhibition
Authors: Weber G. , Lea M. A. , Stamm Nancy B. 
Published: November 2006

AbstractIn recent years experiments in slices, perfused liver and in the whole animal demonstrated that liver carbohydrate metabolism can be controlled by free fatty acids (FFA). Our investigations suggest that FFA and acetyl‐CoA might provide regulation of the rate and direction of opposing pathways of hepatic glycolysis and gluconeogenesis by controlling the activity of key enzyme systems. Long and short chain FFA were observed to selectively inhibit the key enzymes of glucose catabolism, glucokinase, hexokinase, phosphofructokinase and pyruvate kinase. The long chain FFA were inhibitors two magnitudes stronger than octanoate. The FFA were also able to inhibit lactate production in a fortified supernatant fluid system. Acetyl‐CoA inhibited hepatic glucokinase and pyruvate kinase but did not affect liver hexokinase, phosphofructokinase, lactate dehydrogenase, glucose‐6‐phosphatase or fructose‐1, 6‐diphosphatase. The inhibition of glucokinase and pyruvate kinase was dependent on the dose and preincubation time with acetyl‐CoA. The acetyl‐CoA is the end product of the degradation of FFA which in turn is an end product of glucose catabolism; therefore, the inhibition of the three key glycolytic enzymes by FFA and the subsequent reinforcement of the inhibition of glucokinase and pyruvate kinase may be called sequential feedback inhibition. The regulatory role of phosphoenol‐pyruvate, NADH, ATP, alanine and oxaloacetate in the control of hepatic carbohydrate metabolism is discussed.
Methyl octadecadienoates as protectors against inactivation of alkaline phosphatase by γ‐radiation
Authors: Akiya Toshimi , Madson T. H. , Chipault J. R. 
Published: November 2006

AbstractMethylcis, cis‐, cis, trans‐ andtrans,trans‐9,12‐octadecadienoates protect alkaline phosphatase from inactivation by γ‐rays. The three isomers are equally efficient.
Control of metabolism in brown adipose tissue
Authors: Williamson John R. , Prusiner Stanley , Olson Merle S. , Fukami Miriam 
Published: November 2006

AbstractCells and mitochondria were isolated from brown adipose tissue of the adult hamster. Isolated mitochondria did not show respiratory control. Reversed electron transport was demonstrated and the oxidation rates of various substrates were compared. α‐Glycerophosphate gave the highest oxidative rate with isolated mitochondria. The low basal respiration of isolated brown fat cells could be stimulated by catecholamines, oleate, succinate,a‐glycerol phosphate and uncoupling agents. Only norepinephrine or oleate induced respiration was sensitive to inhibition by oligomycin, but this inhibition could not be released by uncoupling agents. Neither atractyloside nor (+) decanoylcarnitine were found to affect respiration, suggesting that mitochondrial nucleotide exchange is slow and that fatty acid oxidation might be carnitine independent. In resting brown fat cells, ATP amounts to 75% of the total adenine nucleotides. NE or oleate caused a small decrease of ATP and a corresponding increase of ADP. Oligomycin caused a partial depletion of ATP content, but subsequent NE addition increased ATP back to control values. This effect was abolished by arsenite. Similarly, uncoupling agents diminished the ATP level which was increased only slightly by NE. Arsenite alone decreased ATP levels to a small extent but a rapid depletion occurred upon subsequent NE addition while respiration was inhibited. Thus, substrate level phosphorylation may be the major energy producing reaction for the generation of ATP and GTP for the activation of fatty acids. Norepinephrine addition to brown fat cells caused an oxidation of pyridine nucleotides, a reduction of flavoproteins and an oxidation of cytochrome b. In constras, succinate produced a reduction of all the components of the respiratory chain. The bioenergetic basis of thermogenesis in brown fat is its high respiratory rate. The rapid respiration induced by norepinephrine or fatty acids appears to be characterized by a low yeild of ATP from oxidative phosphorylation and may be controlled by fatty acid mediated release of energy coupling, possibly by an indirect mechanism.
The comparative oxidation of palmitic, oleic and succinic acids by rat and bat brown adipose tissue homogenates as a function of temperature
Authors: Dryer Robert L. , Paulsrud John R. , Brown Donald J. , Mavis Karol 
Published: November 2006

AbstractThe oxidation of 1‐14C‐palmitic, 1‐14C‐oleic and 2‐14C‐succinic acids to14CO2 by homogenates of brown adipose tissue (BAT) from rat and bat was studied as a function of temperature. In all cases bat BAT gave a greater conversion of added fatty acids to14CO2 than did rat BAT. The conversion of labeled succinate to14CO2 is greater in the bat than in the rat only at low temperatures. In all paired observations below 30 C the energy of activation (EA) of the bat preparations are lower than the rat. This indicates a greater thermal efficiency for the oxidation of the indicated substrates. The bat BAT homogenates show a greater efficiency than rat homogenates in the amount of succinate oxidation associated with the oxidation of long chain fatty acids to CO2. The significance of these findings to thermogenesis by BAT in hibernation and cold adaptation is discussed.
Cholesterol esters of milk and mammary tissue
Authors: Keenan T. W. , Patton Stuart 
Published: November 2006

AbstractThe fatty acid composition and metabolic activity of cholesterol esters in milk and mammary tissue (cow, sow and goat) were investigated. Cholesterol esters of freshly secreted milks incubated at 40 C for 2 hr showed no change in fatty acid composition and no incorporation of 1‐14C‐palmitate. The fatty acid composition of cholesterol esters in the milk of all three species exhibited elevated levels of a unique group of fatty acids when compared to other milk ester lipid classes. This group was comprised of monounsaturated acids and acids with odd numbers of carbons. Tissue cholesterol esters contained lower levels of these acids. Evidence from experiments in which an odd carbon acid (C15) was infused into the lactating mammary gland indicated that the group of unique acids is preferentially retained in the cholesterol ester fraction which is secreted with milk. These infusion experiments also provided evidence that cholesterol esters accumulate in developing milk fat globules in a manner paralleling triglyceride accumulation, and that acyl moieties of cholesterol esters may be desaturated in the form of the intact ester. Our results are compatible with the hypothesis that acyl moieties of cholesterol esters in lactating mammary tissue are turning over rapidly.
Free fatty acids in cultured cells
Authors: Howard Barbara V. , Kritchevsky David 
Published: November 2006

AbstractA method for isolation and quantitation of cellular free fatty acid has been developed. When this method was used to quantitate the free fatty acid content of various cells and tissues, their levels of free fatty acids were found to vary over a wide range. In comparing tissue culture cells having different levels of free fatty acid, it was demonstrated that the conditions of culture and the type of serum in the medium are not responsible for the difference in levels. Isotopic studies have shown that the cellular free fatty acid is not biosynthesized, but is derived from the free fatty acid of the medium. Preliminary studies on the fate of the intracellular free fatty acid and a discussion of possible factors controlling the level of this compound in cells are presented.
Ceramide phosphorylglycerol phosphate a new sphingolipid found in bacteria
Authors: White David C. , Tucker Anne N. 
Published: November 2006

AbstractCeramide phosphorylglycerol phosphate (CPGP) has been identified in the lipid extract of the anaerobic bacteriumBacteroides melaninogenicus. To our knowledge this is the first report of this lipid in biological material. The ceramide derivative contains two phosphates, an amide linked fatty acid and a dihydrosphingosine long chain base. Glycerol diphosphate (PGP) identified by paper and column chromatography can be isolated after mild acid hydrolysis of the ceramide derivative. Inorganic phosphate is liberated quantitatively on treatment of the PGP from the ceramide derivative with alkaline phosphatase. The proportions of the fatty acids found linked to the amide of the dihydrosphingosine (LCB) differ from those esterified to cardiolipin in this organism. The long chain base appears to consist of part of an homologous series of branched and normal LCB containing from 17 to 21 carbon atoms. Previous work has indicated that ceramide phosphorylethanolamine and ceramide phosphorylglycerol (CPG) are present in the lipid extracts ofB. melaninogenicus. By analogy with phosphatidylglycerol synthesis, CPGP is postulated to be an intermediate in the synthesis of CPG.
The effect of dietary sterculic acid on the hepatic lipids of rainbow trout
Authors: Roehm J. N. , Lee D. J. , Wales J. H. , Polityka S. D. , Sinnhuber R. O. 
Published: November 2006

AbstractGroups of young rainbow trout (5 g) were fed a basal diet containing 9% salmon oil and 1% tristearin with 0, 100 or 200 ppm methyl sterculate. Liver lipids were separated into polar and nonpolar fractions and the fatty acids quantitatively analyzed. Significant elevations of the stearic‐oleic and the palmiticpalmitoleic ratios were found in liver fatty acid composition 10 days after the feeding trial began. Liver triglycerides of fish fed methyl sterculate for 87 days contained only 2–3% docosahexenoic acid as compared to 10.69% in control trout, suggesting an effect on the biosynthesis of long chain polyunsaturates. Dietary cyclopropenoid fatty acids (CPFA) suppressed growth rate during the first part of the 200 day feeding trial. After 90 days no differences in the rate of weight gain were observed between the control and CPFA groups. A seven day feeding trial with 0, 5, 20, 50 and 100 ppm CPFA resulted in a maximum change in the stearic‐oleic ratio at 50 and 100 ppm levels. All levels of CPFA increased this ratio and caused marked alterations in the cellular morphology of the liver.
The lipids of thermophilic fungi: Lipid composition comparisons between thermophilic and mesophilic fungi
Authors: Mumma R. O. , Fergus C. L. , Sekura R. D. 
Published: November 2006

AbstractThe lipid composition of nine thermophilic and nine mesophilic species of seven genera of fungi were compared. The total lipids varied between 8.0% and 54.1% with most fungi possessing between 8.0% and 18.3% lipids. The predominant fatty acids were found to be palmitic, oleic and linolenic. Lesser amounts of arachidic, linolenic, palmitoleic, pentadecanoic, myristic and lauric acids were found. The mesophiles varied between 0% and 18.5% linolenic acid, while the thermophiles did not contain any appreciable linolenic acid (<0.5%). The mesophile,Mucor globosus, and the thermophile,Mucor pusillus, contain γ linolenic acid. The fatty acids of the thermophilic fungi were more saturated than the corresponding mesophilic species.
The incorporation of glycerol into the glyceride‐glycerol of fat cells isolated from chronically cold‐exposed rats
Authors: Hubbard R. W. , Voorheis H. P. , Therriault D. G. 
Published: November 2006

AbstractThe rate of 2‐14C‐glycerol incorporation into the glyceride‐glycerol moiety was measured in isolated fat cells from control rats maintained at 25 C and from animals chronically exposed to cold (5 C) for six to eight weeks. The rate of glycerol conversion (μM/μg DNA/30 min) was less in the cold‐exposed rats, than in comparable controls (1.96±0.14 vs. 2.68±0.17). Very little glycerol was oxidized to CO2 or converted to fatty acids. In both groups of animals, the glyceride‐glycerol formation was apparently stimulated by noradrenaline in the presence of glucose, but this incorporation does not significantly bias the estimation of lipolysis based upon glycerol release.
Lipid composition of beef and human pituitary glands
Authors: Singh H. , Carroll K. K. 
Published: November 2006

AbstractThe lipid composition of beef and human pituitary was determined by chromatographic and spectrophotometric methods. Beef pituitary lipid contained about 25% nonpolar lipids and 75% phospholipids whereas nonpolar lipids made up approximately 60% of the total in human pituitaries. The main nonpolar (i.e., low polarity) lipids in human pituitary were triglycerides, cholesterol, free fatty acids and an unidentified component in the triglyceride fraction. Cholesterol was the major nonpolar lipid component in freshly collected beef anterior and posterior pituitary, but the amount of free fatty acids appeared to increase during storage. Preliminary investigation of the unknown nonpolar lipid in human pituitaries suggested that it was an unsaturated hydroxy compound with no carbonyl functions. Thin layer chromatography indicated that it was also present in smaller amounts in freshly collected beef pituitaries. The main phospholipids of beef anterior, posterior and human pituitary were phosphatidyl ethanolamine, phosphatidyl choline, phosphatidyl inositol, phosphatidyl serine and sphingomyelin. The fatty acid composition of total nonpolar lipids, free fatty acids, total phospholipids, phosphatidyl ethanolamine and phosphatidyl choline of beef anterior and posterior pituitary was determined by gas liquid chromatography. Mixtures of saturated and unsaturated fatty acids ranging from C12 to C22 were present; the main fatty acids were palmitic, stearic, oleic, linoleic and arachidonic.
Fatty acids: XXII partial synthesis of racemic helenynolic acid from crepenynic acid by a possible biosynthetic route and the discovery ofcis‐9,10‐epoxyoctadec‐12‐ynoic acid inHelichrysum bracteatum seed oil
Authors: Conacher H. B. S. , Gunstone f. D. 
Published: November 2006

AbstractRacemic helenynolic acid has been prepared from crepenynic acid by epoxidation followed by base‐catalyzed rearrangement. This may be the pathway by which helenynolic acid is produced inHelichrysum bracteatum seed oil from the crepenynic acid also present. A reinvestigation of the epoxy acids in this oil has shown thatcis‐9,10‐epoxyoctadec‐12‐ynoic acid accompanies the coronaric acid previously identified.
Cholesterol absorption with different fats following thoracic duct cannulation of the rat
Authors: Klauda Harry C. , Quackenbush Forrest W. 
Published: November 2006

AbstractRadioactive cholesterol in three unsaturated fats was absorbed into the lymph to the same extent as cholesterol in three saturated fats or in fats which had been stripped of sterols. Absorption on the first day following cannulation was less than half that on subsequent days.
Tropaeolum speciosum seed fat: A rich source ofcis‐15‐tetracosenoic andcis‐17‐hexacosenoic acids
Authors: Litchfield Carter 
Published: November 2006

AbstractTropaeolum speciosum seed fat contains 41.6 wt %cis‐15‐tetracosenoic acid and 7.6 wt %cis‐17‐hexacosenoic acid. Unlike nasturtium seed fat (Tropaeolum majus), the 22∶1, 24∶1 and 26∶1 inT. speciosum triglycerides are almost entirely esterified at the 1,3 positions.
Monounsaturated fatty acids of mouse skin surface lipids
Authors: Wilkinson David I. 
Published: November 2006

AbstractThe occurrence of the various positional isomers of monounsaturated fatty acids of mouse skin surface lipids was studied by conventional oxidative cleavage‐gas liquid chromatography techniques. The pattern observed could be accommodated by the biosynthetic scheme proposed elsewhere for rat skin fatty acids, except that 18∶Δ9 replaced 16∶Δ9 as the main precursor.
Incorporation of U‐14C‐leucine into the serum lipoproteins and proteins of partially hepatectomized rats
Authors: Narayan K. Ananth 
Published: November 2006

AbstractThe incorporation of U‐14C‐leucine into five classes of serum lipoproteins and into lipoprotein‐free serum proteins was investigated in partially hepatectomized, sham operated and normal rats. The serum concentration of very low density lipoprotein and the predominant subfraction of high density lipoprotein (HDL2) was considerably reduced in partially hepatectomized rats as compared with both normal and sham operated rats. The incorporation of U‐14C‐leucine into HDL2 of partially hepatectomized rats was only one third and one fourth of that observed with normal and sham operated rats, respectively. On the other hand, the incorporation of the label into low density lipoproteins and into serum proteins was slightly greater in partially hepatectomized rats as compared with normal rats. In sham operated animals, the incorporation into most fractions was considerably greater than those observed with lobectomized and normal rats.
Mass spectrometry of triglycerides: I. Structural effects
Authors: Lauer W. M. , Aasen A. J. , Graff G. , Holman R. T. 
Published: November 2006

AbstractMass spectra of several triglycerides of specific structure or with specific deuterium labeling have been measured with a low resolution mass spectrometer. With saturated triglycerides the abundances of ions characteristic of the component acids, [M‐RCO2]+, increase with increasing chain length, and [M‐RCO2CH2]+ decrease with increasing chain length. Unsaturation in the acyl moiety causes the abundant formation of [RCO‐1]+. Structures have been suggested for a number of the main peaks obtained from saturated triglycerides, and high resolution spectra of one triglyceride agree with the postulated structures. The peaks, [RCO+74]+, [RCO+115]+ and [RCO+128+14n]+, represent structures which contain the glyceryl portion of the triglyceride, since in case of the replacement of its hydrogens with deuteriums, these peaks are shifted accordingly. Evidence which indicates the possibility of determining the location of unsaturation by the interruption of homology of the [RCO+128+14n]+ series, brought about by the addition of deuterium to the unsaturated linkages, is introduced. Further evidence is also presented, which indicates that the [M‐RCO2CH2]+ ions arise from the positions 1 and 3 and, in agreement with earlier studies from other laboratories, it is thus possible to identify the acyl groups attached to the 1 and 2 positions of the glyceryl moiety.
Mass spectrometry of triglycerides: II. Specifically deuterated triglycerides and elucidation of fragmentation mechanisms
Authors: Aasen A. J. , Lauer W. M. , Holman R. T. 
Published: November 2006

AbstractDeuterium labeled monoacid triglycerides were synthesized and their mass spectra were measured. The spectra provided further support for proposed (1) structures of principal ions, knowledge about the formation of [M‐18]+, the interexchange of hydrogen atoms between 2 and the 5,6 or 7 positions and the explusion of part of the alkyl chain.