bluuebunny/crossref_metadata_2025 huggingface dataset:
Dietary fats and properties of endoplasmic reticulum: I. Dietary lipid induced changes in composition of microsomal membranes in liver and gastroduodenal mucosa of rat
Authors: Laitinen M. , Hietanen E. , Vainio H. , Hänninen O.
Published: December 2006

Rats were fed for four weeks with different lipid diets to determine the effects on the endoplasmic reticulum membranes of the liver and on the postmitochondrial supernatant fraction of the gastroduodenal mucosa. The diets contained cholesterol, cacao butter, olive oil, and these in combination. The results showed that dietary lipids were able to modify the composition of the hepatic endoplasmic reticulum and, to a lesser extent, that of postmitochondrial fraction of gastroduodenal mucosa. Cacao butter in the diet decreased the relative proportion of protein in hepatic microsomes. Cholesterol and olive oil were able to increase the cholesterol content of microsomes. The trypsin digestion of membranes revealed that cholesterol increased the solubility of microsomal protein and decreased the trypsin sensitive protein‐lipid binding. The neutral fat diets increased the binding of proteins to the membrane, and cholesterol had no effect when it was given in combination. The low power photomicrographs revealed vacuolization of the cytoplasm of the hepatocytes when rats were fed on lipid rich diets. Also fatty degeneration was present. Cholesterol in combination with olive oil, however, did normalize the structure of the hepatocytes to a marked extent.
Effects of bacteriophage M13 infection upon phospholipid and fatty acid compositions ofEscherichia coli
Authors: Chattopadhyay P. K. , Dutta J.
Published: December 2006

Escherichia coli K38 were grown and infected with wild type and amber mutants of bacteriophage M13 in the early log phase. Lipid compositions of the infected and healthy cultures, grown under identical conditions, were determined 2 hr after infection. From the results, it was observed that total lipid and total phospholipid content remained nearly constant, suggesting that the cell membrane which contained the maximum phospholipids was not damaged by the infection. Moreover, the percentage of diphosphatidylglycerol and lyso‐compounds corresponding to phosphatidylethanolamine and phosphatidylglycerol increased, while phosphatidylethanolamine and phosphatidylglycerol decreased. The increase in lyso‐compounds may be due to the release of phospholipase A2 (a periplasmic enzyme) from the cell wall after damage by the infection. Bacteriophage M13 infection had no effect on the fatty acid composition of the phospholipids.
Acetylenic acids from mosses
Authors: Anderson W. H. , Gellerman J. L.
Published: December 2006

Two new acetylenic fatty acids, 9, 12‐octadecadien‐6‐ynoic and 11,14‐eicosadien‐8‐ynoic, were identified from lipids of the moss,Fontinalis antipyretica. They resemble the previously identified 9,12,15‐octadecatrien‐6‐ynoic acid by having a methylene interrupted unsaturated system. The C20 acetylenic acid shows that the capability of mosses to synthesize polyolefinic acids of this chain length applies, in certain species, also to olefinic‐acetylenic acids.
NMR spectra of mercury adducts of unsaturated fatty acids: Quantitative determination ofcis‐trans ratio
Authors: Schaumburg Kjeld
Published: December 2006

By stereospecific adduct formation between mercuric acetate and unsaturated fatty acids, derivatives are obtained suitable for NMR determination ofcis‐trans ratio. The preparation and optimal experimental conditions are determined. Experimental data are found to be within a few per cent of the true values.
Retarded hydrolysis by pancreatic lipase of seed oils withTrans‐3 unsaturation
Authors: Kleiman R. , Earle F. R. , Tallent W. H. , Wolff I. A.
Published: December 2006

Triglycerides containing acids withtrans‐3 unsaturation (16∶13, 18∶13 and 18∶33, 9, 12) showed a marked retardation of reaction rate with pancreatic lipase. An inverse relationship was found between content oftrans‐3 unsaturated acids in seed oils and lipolysis rate. Thetrans‐3 unsaturated acids were concentrated in the diglyceride and residual triglyceride fractions of the lipolysates, and only small amounts were present in the free acid and monoglyceride fractions.
Nonconversion of 5,11,14‐eicosatrienoic into arachidonic acid by rats
Authors: Schlenk H. , Sand D. M. , Gellerman J. L.
Published: December 2006

Methyl ester of [U‐14C]5,11,14‐20∶3 was administered to essential fatty acid deficient rats. In contrast to a report by Takagi, it was found that the trienoic acid was not converted into arachidonic acid.
Detection of lithocholic acid in multiple sclerosis brain tissue
Authors: Mujtaba Naqvi S. H. , Ramsey Robert B. , Nicholas H. J.
Published: December 2006

By methods previously employed for detecting lithocholic acid in brains of guinea pigs afflicted with experimental allergic encephalitis, the same acid was detected in a coronal specimen of human brain obtained on autopsy of a multiple sclerosis patient. The specimen contained several well‐defined demyelinated plaque areas. No lithocholic acid was detected in a somewhat larger coronal specimen of normal human brain.
Structure of some intact lipids of petrel stomach oils
Authors: Watts Rodney , Warham John
Published: December 2006

The stomach or proventricular oils from 16 species of petrel have been analyzed and the carbon number distributions of the wax esters, triglycerides, and diacylglyceryl ethers are reported. The wax esters have been fractionated further into less and more polar species. To determine whether any intermolecular specificity existed, carbon number distributions for each lipid class were calculated, assuming random esterifications. The triglyceride and diacylglyceryl ether compositions observed were all found to agree closely with those calculated. The wax esters from three petrel species were found to have greater proportions of the middle range species with carbon numbers 34–38 than calculated. However, most of the lipids examined had random structures which have been found to be characteristic of marine sources. The results in general support the belief that the oils are derived directly from dietary sources rather than synthesis by the proventricular glands.
Tirucalla‐7,24‐dienol: A new triterpene alcohol from tea seed oil
Authors: Itoh T. , Tamura T. , Matsumoto T.
Published: December 2006

A new triterpene alcohol is isolated from tea (Thea sinensis, Theaceae) seed oil, and its structure is shown to be 5α‐tirucalla‐7,24‐dien‐3β‐ol. This triterpene alcohol is considered to be a possible biogenetic precursor to the meliane and meliacan series of oxygenated triterpenes. Gas liquid chromatographic and proton magnetic resonance spectroscopic correlations between euphane and tirucallane series triterpenes also are discussed.
Vitamin E, cholesterol, and lipids during atherogenesis in rabbits
Authors: Bitman Joel , Weyant Joan , Wood D. L. , Wrenn T. R.
Published: December 2006

Rabbits were fed diets including cholesterol and 10% butterfat to determine whether polyunsaturated butter (9% 18∶2) would be less atherogenic than normal saturated butter (3% 18∶2) when fed for 12 weeks. The cholesterol diets alone, 0.5% or 2%, produced aortic plaque development, and plasma cholesterol increased 20 times, lipids increased 10 times, and vitamin E increased 5 times. The inclusion of both fat and cholesterol in the diet produced a synergistic effect, doubling these values to 40 times for cholesterol, 20 times for lipids, and 10 times for vitamin E. The higher circulating levels of cholesterol caused increased tissue levels of cholesterol. With 2% cholesterol and fat, liver and aorta cholesterol increased 10 times, heart 4 times, and muscle cholesterol 2 times. The lower 0.5% dietary cholesterol load was successful in limiting the amount of tissue cholesterol increase. Liver, aorta, heart, and muscle levels of cholesterol were only about half the concentration attained when 2% cholesterol was fed. It was concluded that there were no differences in plasma or tissue cholesterol, vitamin E, or atherosclerosis attributable to the polyunsaturated nature of the diet. The 10% butterfat diets alone, whether saturated or unsaturated, did not induce aortic plaques and did not increase blood or tissue cholesterol, lipids, or vitamin E. Our results suggest that the lipid mobilizing effect is mediated by cholesterol, probably by conversion to bile acids and a stimulation in intestinal absorption.
Site of bile acid absorption in the rat
Authors: Sklan D. , Budowski P. , Hurwitz S.
Published: December 2006

Bile acid absorption was measured in the small intestine of the rat using91Y as a nonabsorbed reference substance. Some 50% of the secreted bile acids were absorbed in the proximal half of the small intestine. In situ incubations of ligated intestinal segments into which tauro(14C‐carbonyl)cholic acid was introduced confirmed the considerable uptake of bile acids in the jejunum. The in situ experiments indicated that serosal transport is the limiting stage of bile acid absorption in the jejunum but not in the ileum. Increasing bile acid concentrations in the in situ experiments did not affect the percentage disappearance of dose from the jejunum but reduced the percentage mucosal uptake in the ileum. It is concluded that, in the rat, the proximal small intestine is as important in the absorption of bile acids as the distal small intestine.
Chemiluminescent autoxidation of linolenic acid films on silica gel
Authors: Slawson Vida , Adamson Arthur W.
Published: December 2006

Films of linolenic acid supported on chromatographic type silica gel undergo autoxidation at a rate which is slow compared to that in homogeneous phase at low surface coverage but comparable to it at coverages approximating a close‐packed monolayer. The new observation reported here is that these surface phase oxidations are chemiluminescent. The quantum yield is ca. 10−12 quanta per molecule of fatty acid reacted for a close‐packed monolayer and remains approximately constant with decreasing coverage. The emission intensity is temperature dependent, with an apparent activation energy of 10 kcal mol−1, and shows an induction period for close‐packed monolayers. The emission spectrum contains a component consistent with excited state ketone emission and a low energy component, ca. 600+ nm, which could be due to singlet oxygen emission. The existence of the emission means that surface autoxidation reactions can be followed in place; the nature of the emission may provide insight into the autoxidation mechanism beyond that which may be inferred from conventional rate measurements.
Esterified alkan‐1‐ols and alkan‐2‐ols in barley epicuticular wax
Authors: von Wettstein‐Knowles P. , Netting A. G.
Published: December 2006

The epicuticular wax on all barley organs is characterized by the presence of long chain esters which have alkan‐1‐ols as their alcohol moiety (mainly C38−C48). A second type of long chain ester in which alkan‐2‐ols serve as the alcohol moiety has been identified in the wax from all organs except the awns and leaf blades (mainly C33−C35). Utilizing Silica Gel H column chromatography, a 95% separation of the two ester types was achieved. Unlike alkan‐1‐ols, the alkan‐2‐ols (primarily C13 and C15) do not occur free in the wax. Esters isolated from spike minus awn wax consisted of 62% alkan‐2‐ol and 38% alkan‐1‐ol containing esters. The isomeric composition of each ester was determined with the aid of gas liquid chromatography‐mass spectrometry. In the mass spectra of the alkan‐2‐ol containing esters, mass ions were absent and the relative intensities of the RCO2H2+, RCO2H+, [R′‐1]+, and RCO+ ions were markedly different from those characteristic for alkan‐1‐ol containing esters. Since esterified alkan‐2‐ols occur only in those waxes having β‐diketones, a close biosynthetic relationship between these two lipid classes is suggested.
Specific inhibition of hepatic fatty acid synthesis exerted by dietary linoleate and linolenate in essential fatty acid adequate rats
Authors: Clarke S. D. , Romsos D. R. , Leveille G. A.
Published: December 2006

Dietary linoleate and linolenate were investigated for their ability to specifically inhibit liver and adipose tissue lipogenesis in meal‐fed (access to food 900‐1,200 hr), essential fatty acid (EFA) adequate rats. Supplementing a high carbohydrate diet containing 2.5% safflower oil with 3% palmitate 16∶0, oleate 18∶1, or linoleate 18∶2 did not affect in vivo liver or adipose tissue fatty acid synthesis. However, 18∶2 addition to the basal diet did result in a significant (P<0.05) decline of liver fatty acid synthetase (FAS) and glucose‐6‐phosphate dehydrogenase (G6PD) activities. When the safflower oil content of the basal diet was reduced to 1%, the addition of 3% 18∶2 or linolenate 18∶3 significantly (P<0.05) depressed hepatic FAS, G6PD, and in vivo fatty acid synthesis by 50%. Addition of 18∶1 caused no depression in hepatic FAS activity but did result in a significant (P<0.05) decline in liver G6PD activity and fatty acid synthesis which was intermediate between basal and basal +18∶2‐or+18∶3‐fed animals. Adipose tissue rates of lipogenesis were completely unaffected by dietary fatty acid supplementation. Similarly, the addition of 3 or 5% 18∶3 to a basal diet for only one meal resulted in no change in lipogenesis relative to that in animals fed the basal diet. The data indicate that, like rats fed EFA‐deficient diets, dietary 18∶2 and 18∶3 exert a specific capacity to depress rat liver FAS and G6PD activities and rate of fatty acid synthesis.
Effects of dietary saturated andtrans fatty acids on cholesteryl ester synthesis and hydrolysis in the testes of rats
Authors: Takatori Takehiko , Phillips Frederick , Privett Orville S.
Published: December 2006

Studies were made of the enzymic synthesis and hydrolysis of cholesteryl esters in rat testes. Weanling rats were fed for 14 weeks diets containing 5% by wt of hydrogenated coconut oil (HCO), a concentrate of ethyl elaidate and linolelaidate (TRANS), devoid of essential fatty acids (EFA), or safflower oil (SAFF). Cholesterol esterifying activity was localized in the soluble fraction, and cholesteryl ester hydrolase activity was distributed in both particulate and soluble fractions obtained from tissue homogenates. The optimum pH was 6.0 for esterification and 6.9–7.0 for hydrolysis. Neither esterifying nor hydrolytic activity was affected by freezing and thawing, but both reactions were inhibited by heat or sonication. The animals of both the HCO and TRANS groups had developed an EFA deficiency before they were sacrificed. The EFA deficiency produced upon feeding the HCO diet had no apparent effect on the synthesis and hydrolysis of cholesteryl esters in rat testes. The TRANS diet influenced the development of the testes as judged by their size, and cholesterol esterifying and cholesteryl ester hydrolyzing activities were suppressed in the testes of the animals of this group. A major difference in the effects of the HCO and TRANS diets on the lipids of the testes was the relatively minor amount of eicosatrienoic acid (20∶3) and the elevated level of docosapentaenoic acid (22∶5) in the cholesteryl esters of the testicular lipids of the TRANS group.
Comparative antilipidemic effects of various ethyl 5‐substituted benzofuran‐, 2,3‐dihydrobenzofuran‐, and 3(2H)‐benzofuranone‐2‐carboxylate analogs of clofibrate in a triton hyperlipidemic rat model
Authors: Witiak Donald T. , Newman Howard A. I. , Poochikian Guiragos K. , Loh William , Sankarappa Shankar K.
Published: December 2006

The antilipidemic properties of certain benzofuran‐, 2,3‐dihydrobenzofuran‐, and 3(2H)‐benzofuranone‐2‐carboxylate analogs of clofibrate in a hyperlipidemic rat model are described. The hyperlipidemia was induced by intraperitoneal injection of Triton WR‐1339. The results were analyzed in light of structural modifications as well as the lipid solubility of substituted compounds as assessed by a consideration of calculated log P values. Comparisons are made between the activity of these compounds and the activity of related cyclic analogs previously reported. Among the various compounds tested, only the 5‐C1 and phenylsubstituted dihydrobenzofurans were selective against elevated serum cholesterol levels in this animal model. The data presented support the hypothesis that the cholesterol and triglyceride lowering activity of clofibrate related analogs in this animal model may be separated through a consideration of log P, conformational, and electronic changes. The proposal is advanced that relatively minor structural modification of clofibrate related analogs may lead to compounds which are not only selective in the Triton model but also to compounds which are likely to exert their effects by differing modes of action.
Free radical reactions of peroxidizing lipids with amino acids and proteins: An ESR study
Authors: Schaich Karen M. , Karel Marcus
Published: December 2006

Free radical transfer from oxidizing methyl linoleate to amino acids and proteins was studied in dry model systems incubated for periods up to 20 days. Electron spin resonance was used to study free radical production. Free radicals were detectable in the amino acids lysine, arginine, histidine, tryptophan, and cysteine. Reduced glutathione and, to a limited extent, cystine also gave free radical signals. Free radicals produced in proteins primarily showed central singlet lines, attributable to carbon‐centered radicals, with g=2.004±0.001. Sulfhydryl proteins also exhibited downfield shoulders at g≄2.015 and 2.023 that were essentially identical to peaks observed in cysteine and reduced glutathione. The field positions of sulfur resonance in cysteine and proteins suggested a sulfur‐oxygen complex rather than thiyl radicals.
Biosynthesis of fatty acids by the carp,Cyprinus carpio L., in relation to environmental temperature
Authors: Farkas Tibor , Csenger Istvan
Published: December 2006

Incorporation in vivo of sodium 1‐14C‐acetate into different lipid classes and fatty acids of total lipids and phospholipids of warm adapted and cold adapted carp livers was studied at 5 C and 22 C, respectively. The fatty acid composition of total lipids and phospholipids was also determined. The level of long chain polyunsaturated fatty acids in both total lipid and phospholipid fractions was higher in cold adapted fish than in warm adapted ones. The distribution of radioactivity among different lipid classes depended only on the actual incorporation temperature and was independent of the temperature history of the animals. Livers of fish incorporated a higher percentage of radioactivity into long chain polyunsaturated fatty acids of total lipids and phospholipids in 5 C than in 22 C. The distribution of radioactivity among different fatty acids was dependent on the experimental temperature rather than on the temperature to which the fish were adapted. The results suggest that fish are able to adjust the pattern of the biosynthesis of fatty acids very rapidly to the prevailing temperature and to assure by this way the proper physicochemical properties of their membranes. The possible mechanisms involved in this rapid response are discussed.
Mass spectra of acetylenic fatty acid methyl esters and derivatives
Authors: Kleiman R. , Bohannon M. B. , Gunstone F. D. , Barve J. A.
Published: December 2006

A series of isomeric methyl octadecynoates was analyzed by mass spectrometry; each isomer gave a unique spectrum. The characteristic ions were those resulting from a McLafferty rearrangement of the allenic sites or of the already‐rearranged allenic sites. The acetylenic esters were also subjected to oxymercuration whereupon a carbonyl group was formed at either of the original actylenic carbon atoms providing two oxostearates. Further reaction with NaBH4 formed hydroxy esters which, after silylation, gave diagnostic mass spectra indicative of the triple bond location. Applied to esters with both double and triple bonds, this procedure permitted differentiation between the two types of unsaturation. Methoxyl groups marked the original double bond locations and hydroxyls did so for triple bonds.
Kinetics of absorption, equilibration (or distribution), and excretion of orally and intraperitoneally administered cholesterol in the rat
Authors: Adam A. , Van Cantfort J. , Gielen J.
Published: December 2006

Resorption and metabolism of cholesterol administered intraperitoneally and per os have been described in the rat utilizing a technique of double isotopic labeling. Depending upon the route of administration, these parameters vary to a large degree. Alimentary cholesterol is progressively resorbed over a period of 10 hr, while the maximal blood level of cholesterol is attained after the 6th hr following intraperitoneal injection. On the other hand, cholesterol administered per os is more rapidly utilized in biliary acid synthesis than cholesterol administered intraperitoneally. In the range of concentrations utilized in this work (10–300 μg and 0.2–300 μg, respectively, administered to the rat, orally and intraperitoneally), the rate of cholesterol resorption remained constant.
Studies on drug‐induced lipidosis: VII. Effects of bis‐β‐diethylaminoethylether of hexestrol, chloroquine, homochlorocyclizine, prenylamine, and diazacholesterol on the lipid composition of rat liver and kidney
Authors: Yamamoto Akira , Adachi Susumu , Matsuzawa Yuji , Kitani Teruo , Hiraoka Akira , Seki Ko‐Ichi
Published: December 2006

4,4′‐Bis (β‐diethylaminoethoxy)‐α,β‐diethyldiphenylethane (DH), which had been shown to induce a type of lipidosis resembling Niemann‐Pick disease, was given to rats at a dose of 20, 50, 100, and 150 mg/kg body weight per day for 1 or 2 weeks. An enlargement of the liver with marked increases in free cholesterol, total phospholipids, and phosphatidylinositol took place by administration of a larger dose. The increase in bis (monoacylglyceryl) phosphate (BMGP), which is peculiar to this kind of drug‐induced lipidosis, was dependent upon the dose of the drug as well as the length of time. Similar changes were also observed in kidney. Among several other drugs tested, chloroquine and diazacholesterol brough on as much increase in BMGP as treatement with DH.
A study of the heparin‐manganese chloride method for determination of plasma α‐lipoprotein cholesterol concentration
Authors: Ishikawa T. T. , Brazier J. B. , Steiner P. M. , Stewart L. E. , Gartside P. S. , Glueck C. J.
Published: December 2006

To assess the limits of the heparin‐MnCl2 precipitation method for quantitation of α‐lipoprotein cholesterol (C‐HDL), effects of varying final MnCl2 and heparin concentrations were studied, and the precipitation method was compared to preparative ultracentrifugation. In 65 parallel plasma aliquots, C‐HDL determined by ultracentrifugation (54.3±1.8 mg/dl) correlated significantly (r=0.98, P<0.001) with the precipitation method (56.0±1.9 mg/dl). C‐HDL by ultracentrifugal and precipitation methods were also similar in 16 subjects with triglycerides ranging from 150 to 312 mg/dl (41.4±2.6, 43.4±2.8, r=0.97, P<.001). A constant amount of cholesterol in the supernatant was measured over a final MnCl2 range of 0.046–0.23M, and cholesterol values in the supernatant at final MnCl2 concentrations of 0.046, 0.05, and 0.055M did not differ from each other, P>0.1. However, cholesterol levels in the supernatant at final MnCl2 concentration of 0.042M differed from those at concentrations of 0.046, 0.05, and 0.055M, P<0.05, and the amount of supernatant cholesterol increased as the final MnCl2 concentration was reduced from 0.042 to 0.02M. A constant amount of cholesterol in the supernatant was measured over a heparin concentration range of 92–734 USP units/ml. The final MnCl2 and heparin concentrations of 0.046M and 184 USP units/ml, which are incorporated in widely used procedures, gave C‐HDL values for the precipitation method which were in close agreement with the ultracentrifugal method. There is no evidence for a heparin‐Mn++ precipitation of HDL and systematic underestimation of HDL by the precipitation method. However, the final MnCl2 concentration is very near the minimum required for accurate measurement of C‐HDL. To preclude incomplete precipitation of low and very low density lipoproteins by insufficient manganese concentration, an increase of the manganese concentration should be considered.
Fecal long chain fatty acids and colon cancer risk
Authors: Sperry J. F. , Salyers A. A. , Wilkins T. D.
Published: December 2006

To determine whether excretion of high concentrations of long chain fatty acids might be associated with high colon cancer risk, we compared concentrations of major long chain fatty acids in the feces of four populations at different risk for colon cancer. Concentrations of C18∶1 were found to be significantly higher (P<0.05) in the feces of the two high risk populations than in the feces of the two low risk populations.
Binding of squalene, lanosterol, desmosterol, and cholesterol to proteins in brain and liver 105,000 g supernatant fractions: Evidence for specific binding sites
Authors: Johnson Ronald C. , Shah Shantilal N.
Published: December 2006

The binding of squalene, lanosterol, desmosterol, and cholesterol to proteins in 105,000 g supernatant fraction (S105) from brain and liver of rats was investigated. The S105 fractions from both tissues contain specific binding sites for sterols, which are sensitive to trypsin. The dissociation constants for squalene and sterol protein complexes were in the range of 10−6 M and were not appreciably different for proteins in brain and liver S105. Competition studies revealed that both brain and liver S105 contain one receptor protein which binds lanosterol and is specific for methyl sterols, and a second receptor which binds both desmosterol and cholesterol. Binding of 7‐dehydrocholesterol reported by others must occur at a third independent site since this compound does not interfere with the binding of lanosterol, desmosterol, or cholesterol. Although binding of squalene to proteins in brain and liver S105 does occur, we were unable to show the specificity of squalene binding. The concentration of desmosterol and cholesterol binding sites, which ranged from 6 to 10 nmol/mg protein, was 3‐ to 5‐fold higher than the concentration of squalene and lanosterol binding sites (1.6–2.3 nmol/mg protein). The brain S105 from suckling rats contained fewer binding sites for desmosterol and cholesterol than the brain S105 from weaned rats. However, the concentration of lanosterol binding sites in brain S105 did not show an age‐dependent change. The receptor proteins in brain and liver appear to be identical.
Effects of rapeseed oil on fatty acid oxidation and lipid levels in rat heart and liver
Authors: Galli Kienle M. , Cighetti G. , Spagnuolo C. , Galli C.
Published: December 2006

The comparative rates of oxidation of erucic and oleic acids and of their CoA esters were studied in heart and liver mitochondria of rats fed a standard diet or semisynthetic diets containing 25% of the calories as either rapeseed oil (46.6% erucic and 10.4% eicosenoic acid) or olive oil, for a period of 5 months. The long exposure to the diet containing 25% rapeseed oil did not alter the oxidative activity of mitochondria and did not induce morphological changes in the heart. It is confirmed that erucic acid is oxidized in mitochondria at lower rates than other long chain fatty acids and that its activation as CoA derivative may be one of the rate limiting steps of the overall oxidation process. Total lipids and triglycerides do not significantly change in the heart whereas they increase in the liver of rats fed the diet containing rapeseed oil.
Monoacyl‐sn‐glycerol 3‐phosphate acyltransferase specificity in bovine mammary microsomes
Authors: Kinsella John E.
Published: December 2006

The acyl‐CoA∶:acyl‐sn‐glycerol 3‐phosphate acyltransferases located in the microsomal fraction of lactating bovine mammary tissue show a preference for palmityl‐CoA particularly above the apparent Km values of the acyl acceptors. Using saturating levels of monopalmityl‐sn‐glycerol 3‐phosphate, the order of acylation was palmityl‐>myristyl‐> oleyl‐>stearyl‐>linoleyl‐CoA. Apparent Km values for monopalmityl‐ and monooleyl‐sn‐glycerol 3‐phosphate with palmityl‐CoA as donor were 16 and 13μM, respectively, while the Km values for palmityl‐CoA with these two acyl acceptors were 5 and 5.2μM, respectively. The apparent Vmax values for the palmityl acceptor and donor were 25 and 30 nmol/min/mg protein. Phosphatidic acid was the principal product. The inclusion of magnesium in the assay depressed activity while the addition of ethylenediaminetetraacetate doubled the rate of acylation.
Occurrence of 2‐ and 3‐hydroxy fatty acids in high concentrations in the extractable and bound lipids ofFlavobacterium meningosepticum andFlavobacterium IIb
Authors: Yano I. , Ohno Y. , Masui M. , Kato K. , Yabuuchi E. , Ohyama A.
Published: December 2006

The major hydroxy fatty acids of cellular lipids inFlavobacterium meningosepticum andFlavobacterium sp. King's group IIb were identified as 2‐hydroxy 13‐methyltetradecanoic, 3‐hydroxy 13‐methyltetradecanoic, 3‐hydroxy palmitic, and 3‐hydroxy 15‐methylhexadecanoic acids using gas chromatography‐mass spectrometry and GC‐mass fragmentography. The concentration of these hydroxy fatty acids comprised up to 30–40% of the total extractable and 20–30% of the bound lipid fatty acids, respectively. From the stability for mild alkaline hydrolysis, 2‐hydroxy fatty acids seemed to be attached with ester linkage, and 3‐hydroxy fatty acids with amide linkage.
Biosynthesis of polyunsaturated fatty acids in the developing brain: II. Metabolic transformations of intracranially administered [3‐14C] eicosatrienoic acid, evidence for lack of Δ8 desaturasedesaturase
Authors: Dhopeshwarkar Govind A. , Subramanian Carole
Published: December 2006

[3‐14C] Eicosatrienoic acid (Δ11,14,17) chemically synthesized from [1‐14C] linolenic acid was injected intracranially into 14‐day old rats and sacrificed 8 hr later. The analysis of brain fatty acids by radio‐gas liquid chromatography before and after ozonolysis showed that the tetraene fraction consisted of a desaturated product, Δ5,11,17–20∶4, and its elongated product, Δ7,13,16,19–22∶4. Both of these products, with a combined total of 61% of the total radioactivity recovered in the tetraene fraction, contain a nonmethylene interrupted double bond system and, therefore, are unsuitable for further desaturation. The other two components, Δ6,9,12,15–18∶4 and Δ8,11,14,17–20∶4, must have been formed from Δ9,12,15–18∶3, formed by retroconversion of the starting material 20∶3, followed by desaturation and elongation. These results suggest a lack of Δ8 desaturase in the developing brain, leading to formation of Δ5,11,14,17–20∶4 rather than Δ8,11,14,17–20∶4. Howeve, the nonmethylene interrupted double bond isomer does not restrict chain elongation.
Lipid synthesis by perfused lung
Authors: Tombropoulos Elias G. , Hadley John G.
Published: December 2006

An isolated lung ventilated with pulses of negative pressure and perfused through the pulmonary vasculature was utilized for the study of 3‐sn‐phosphatidylcholine synthesis. The perfusion fluid consisted of a Krebs‐Ringer phosphate buffer with 6% bovine serum albumin, pH 7.4, and the appropriate substrate. The simultaneous incorporation of (1‐14C) palmitate and (2‐3H) glycerol and the simultaneous incorporation of (CH3‐14C) choline and (CH3‐3H) methionine were examined. From these experiments it is concluded: 1) lung tissue incorporates (2‐3H) glycerol into 3‐sn‐phosphatidylcholine to a greater extent than any other lipid examined; 2) both choline and methionine contribute to the synthesis of 3‐sn‐phosphatidylcholine, and 50–70% of the label in its nitrogen base is derived from choline and 30–50% from methionine; and 3) a high PO2 appears to reduce the synthesis of 3‐sn‐phosphatidylcholine.
Cardiopathogenicity of rapeseed oils and oil blends differing in erucic, linoleic, and linolenic acid content
Authors: McCutcheon J. S. , Umermura T. , Bhatnagar M. K. , Walker B. L.
Published: December 2006

Male Wistar rats were fed semipurified diets containing 20% fat for 25 weeks. Ten different oils or oil blends were employed, including rapeseed oils, simulated rapeseed‐type oils, and modified rapeseed‐type oils. Safflower, soybean, and hydrogenated coconut oils served as control oils. Histopathological examination of the cardiac tissue was conducted at the end of the study and an incidence‐severity rating assigned to the lesions induced by each fat. Oils containing high levels of erucic acid (26–30%) induced the most severe cardiac necrosis, irrespective of the source of erucic acid (rapeseed oil or nasturtium oil). Increasing the linoleic: linolenic acid ratio of the high erucic oils to that of soybean oil failed to reduce necrosis, but the absence of linolenic acid from a high erucic acid oil blend resulted in a markedly reduced lesion incidence‐severity rating, comparable to those obtained for low erucic acid rapessed oil and soybean oil which were similar. Lowest lesion incidence was obtained with safflower oil and hydrogenated coconut oil. We have postulated that linolenic acid plays a role in the etiology of cardiac necrosis observed when rats are fed diets containing low erucic acid rapeseed oils.
Effect of cholesterol and cholestyramine feeding and of fasting on sterol synthesis in the liver, ileum, and lung of the guinea pig
Authors: Turley S. D. , West C. E.
Published: December 2006

The effects of feeding diets containing either cholesterol (0.24% w/w) or cholestyramine (2.5% w/w) and of fasting on sterol synthesis in the liver, ileum, and lung of both male and female guinea pigs have been studied by measuring the incorporation by tissue slices of14C‐labeled acetate into total digitonin‐precipitable sterols. Cholesterol feeding significantly decreased (P<0.05) sterol synthesis in the liver, ileum, and lung of the males and in the ileum of females. Cholestyramine feeding stimulated the rate of hepatic sterol synthesis 13‐fold but did not significantly affect sterologenesis in the ileum. Sterol synthesis in the lung was significantly increased (P<0.05) but to a much lesser extent than in the liver. Fatty acid synthesis in the liver, ileum, and lung was not significantly affected by either cholesterol or cholestyramine feeding. In guinea pigs fasted for 24 hr, sterol synthesis was inhibited in all three tissues, the most pronounced effect occurring in the liver. Only in the lung was fatty acid synthesis significantly decreased (P<0.001) by fasting. Cholesterol feeding resulted in increased concentrations of cholesterol in the plasma and liver. Cholestyramine feeding reduced plasma cholesterol concentration by 81% in females and by 64% in males. However, it did not significantly change the tissue cholesterol concentrations. Fasting resulted in a significant increase (P<0.05) in plasma cholesterol concentration but did not affect the concentration of cholesterol in the tissues. It was concluded that in the normal guinea pig, the feedback inhibition produced by both cholesterol and also possibly by bile acids suppresses sterol synthesis in the liver to very low rates compared to those in the small intestine, where sterologenesis is not only less sensitive to the cholesterol negative feedback system than that in the liver, but also is not subject to regulation by the bile acid negative feedback system.
Initial cholesterol uptake by everted sacs of rat small intestine: Kinetic and thermodynamic aspects
Authors: Chow San‐Laung , Hollander Daniel
Published: December 2006

The kinetics of initial cholesterol uptake by everted rat proximal and distal small intestinal sacs were evaluated in vitro. The mucosal incubation solution consisted of 0.05 mM cholesterol solubilized in 4.8 mM sodium taurocholate micellar solution at pH 7.4. Experiments were performed at temperatures from 26 to 38 C. The rate of cholesterol uptake followed a linear relationship when plotted against time indicating an apparent zero‐order kinetics mechanism for initial uptake. An Arrhenius plot of the results of uptake versus temperature remained linear over the entire range of temperatures studied. The large free energy of activation (20 kcal/mole) suggests that an energy barrier for cholesterol uptake exists at the enterocyte luminal cell membrane and may be an important limiting step in cholesterol uptake. It is proposed that a transient association between cholesterol and a component of the enterocyte luminal cell membrane is formed during initial uptake of cholesterol. The transient association may be an activated complex formed with proteins present at or within the luminal enterocyte cell membrane.
The effects of certain ecdysteroids and inhibitory amines and amides on the metabolism of 22,25‐dideoxyecdysone in cockroach organ cultures
Authors: Marks Edwin P. , Robbins William E. , Thompson Malcolm J.
Published: December 2006

An organ culture assay system using cockroach leg regenerates and fat body has been developed in which compounds that either inhibit molting hormone metabolism or act as molting hormone antagonists can be tested. Representatives of three classes of compounds were tested in the system: ecdysteroids, azasteroids, and nonsteroidal amines and amides. Inhibitory compounds were found in all three of the classes. Certain of these inhibitors represent a new class of insect hormonal compounds with a novel mode of action—the disruption of molting hormone metabolism.
Steric requirements for the stimulation of glycosyltransferase activity by lysophosphatidylcholine
Authors: O'Doherty P. J. A.
Published: December 2006

1‐Palmitoyl‐sn‐glycerol‐3‐phosphocholine and 3‐palmitoyl‐sn‐glycerol‐1‐phosphocholine have been found to be equipotent in the stimulation of membrane‐bound glycosyltransferases in microsomes of rat intestinal villus cells. This indicates that the stimulatory effect of lysophosphatidylcholine is not stereospecific, but that it may be related to a specific detergent property dependent upon the peculiar balance of hydrophilic and hydrophobic components in the molecule.
Prostaglandin metabolism by human testis
Authors: Carpenter M. P. , Robinson R. D. , Thuy L. P.
Published: December 2006

Human testis preparations appear to carry out both the synthesis and turnover of prostaglandins. Prostaglandins and prostaglandin metabolites were extracted from whole tissue. Testis microsomes converted both endogenous and exogenous substrate to prostaglandins. Microsomal prostaglandin biosynthesis was inhibited by indomethacin. Prostaglandin E2‐9‐ketoreductase was present in both the cytosolic and microsomal fractions of human testis. Prostaglandin metabolism by human testis has not previously been reported.
Factors affecting fatty acid oxidation in bovine mammary tissue
Authors: Dimenna G. P. , Emery R. S.
Published: December 2006

Oxidation of fatty acids was studied in bovine mammary tissue slices in order to evaluate their potential contribution to energy metabolism. Rates of fatty acid oxidation decreased with increasing chain length: acetate>octanoate>palmitate or oleate. Rates of oxidation of long chain, but not short chain, fatty acids increased over time, which could not be explained by carnitine palmitoyltransferase (CPT) activity. This phenomenon is not an artifact of the incubation system or caused by substrate solubility, as rates of palmitate oxidation were constant in rat kidney cortex slices. Preincubating mammary tissue with or without unlabeled palmitate showed that increasing rates of palmitate oxidation is not caused by use of endogenous fatty acids. Palmitate at 0.26 mM, equivalent to arterial fatty acid concentration, gave maximal rates of oxidation. The β‐oxidation enzymes may restrict fatty acid oxidation as oxidation of [1‐14C] palmitate exceeded that of [U‐14C] palmitate. Acetate inhibited palmitate oxidation (75%) but not esterification, suggesting that acetate inhibits palmitate oxidation by substrate competition at the mitochondrial level or via malonyl‐CoA inhibition of CPT. Glucose inhibited palmitate oxidation (67%) and stimulated esterification. Low palmitoyl‐CoA levels would favor glyceride synthesis over oxidation, since the apparent Km for palmitoyl‐CoA, of the glycerol‐3‐phosphate acyltransferases is lower than that for CPT. Thus, glucose presumably diverts palmitate from oxidation to glycerolipids. Clofenapate, a glyceride synthesis inhibitor, decreased triacylglycerol formation, and marginally increased palmitate oxidation. We estimated that long chain fatty acids can potentially account for 6–10% of the oxidative metabolism of mammary tissue.
Glucagon and N6,O2′‐dibutyryl adenosine 3′∶5′‐monophosphate inhibition of lipogenesis and phosphofructokinase activity of hepatocytes from meal‐fed rats
Authors: Ochs Raymond S. , Harris Robert A.
Published: December 2006

Glucagon and N6,O2′‐dibutyryl adenosine 3′∶5′‐monophosphate (dibutyryl cyclic AMP) inhibit net glucose utilization, lactate plus pyruvate accumulation and fatty acid synthesis by isolated hepatocytes prepared from meal‐fed rats. A crossover in the metabolite profile of the glycolytic intermediates occurs between fructose‐6‐phosphate and fructose‐1,6‐bisphosphate, suggesting either inhibition of phosphofructokinase or activation of fructose diphosphatase, or both. Direct assay of the enzymes in cell‐free extracts of the hepatocytes indicates that dibutyryl cyclic AMP inhibits phosphofructokinase but has no effect upon fructose diphosphatase. The assay for phosphofructokinase was modified by the use of ITP in place of ATP for the phosphate donor as the ATP‐linked assay is complicated by an apparent time‐dependent activation of the enzyme. These findings strongly suggest that cyclic AMP inhibition of phosphofructokinase explains in part cyclic AMP inhibition of aerobic glycolysis and lipogenesis by rat liver hepatocytes.
Effect of dietary fatty acid composition on the biosynthesis of unsaturated fatty acids in rat liver microsomes
Authors: Kurata Norimasa , Privett O. S.
Published: December 2006

A study was made of the influence of semisynthetic diets of low and high unsaturation on the fatty acid composition and desaturation‐chain elongation enzymatic activity of the liver microsomal fractions of male Sprague‐Dawley rats of different ages. Groups of rats were fed 5 or 20% coconut oil (CO), or a 5 or 20% mixture of corn and menhaden oils (3∶7) (CME) from weaning to 100 wk of age. Growth rate and food consumption were measured during this period in which animals were sacrificed at 36, 57, 77 and 100 wk of age. Both the level and composition of the dietary fat supplements produced marked effects on the fatty acid composition of the liver microsomal lipids. In general, the fatty acid composition of the microsomal fractions reflected that of the dietary fat and was more unsaturated with the higher level of fat fed. The rate of conversion of linoleic to arachidonic acid in assays performed in vitro with liver microsomal preparations from animals of the different groups also showed marked differences. The 6‐desaturase‐chain elongation activity was higher in the 5% than 20% group and corresponded to the essential fatty acid (EFA) status of the animals in these groups as represented by the triene‐tetraene ratio of the microsomal lipid. The relationship of the 6‐desaturase activity to fatty acid composition of the microsomal lipid indicated that if varied directly with the level of 20∶3ω9, 18∶1 and 16∶1 and was inhibited by arachidonic acid. The activity of the 6‐desaturase enzyme system was lowest in the liver microsomal fraction obtained from the animals fed the CME diets and appeared to be suppressed by the high levels of 20∶5 and 22∶6 that accumulated in the microsomal lipid. Accordingly, the levels of arachidonic acid were lower in the microsomal lipid of these groups than those of the corresponding CO groups in spite of a greater abundance of linoleic acid in the diet. The data suggest that the activity of the 6‐desaturase‐chain elongation system is regulated by the fatty acid composition of the microsomal lipid as influenced by the composition of the dietary fat.
Lipids of myocardial membranes: Susceptibility of a fraction enriched in sarcolemma to hydrolysis by an exogenous mammalian phospholipase A2
Authors: Owens K. , Pang D. C. , Franson R. C. , Weglicki W. B.
Published: December 2006

A myocardial membrane fraction enriched in sarcolemma was used to determine the susceptibility of the lipids to hydrolysis by a phospholipase A2 from granulocytes. After incubation (37 C, pH 7.0, 5 mM Ca2+) with the phospholipase A2 for 30 min, a more than 3‐fold increase in unesterified fatty acids was found (up to 47 nmol/mg protein; P<0.001) relative to a control incubated without phospholipase A2 or Ca2+. This included a 10‐fold increase in the arachidonic acid content (up to 42 mol %) and at least a 7‐fold increase in lysophosphatidylethanolamine (up to 7.4 mol% total phospholipid‐P). However, the exogenous phospholipase did not augment the quantity of lysophosphatidylcholine produced by endogenous phospholipases in the presence of Ca2+ (5 mM). These results demonstrate the in vitro susceptibility of phospholipids of myocardial membranes, particularly phosphatidylethanolamine, to the neutral‐active, Ca2+‐dependent phospholipase A2 from granulocytes. This work may be relevant to myocardial inflammation and tissue damage during ischemia, where heterolytic injury of the myocardium may occur subsequent to the accumulation of granulocytes.
Comparison of pyrrolidides with other amides for mass spectral determination of structure of unsaturated fatty acids
Authors: Andersson B. Å. , Heimermann W. H. , Holman R. T.
Published: December 2006

Amides of unsaturated fatty acids give mass spectra which indicate the locations of the double bonds. A survey of several amides of oleic acid was made to evaluate which amide might be most suitable for routine use in elucidation of structure. Methods of preparation of several amides of oleic acid are presented with mass spectral and gas chromatographic data. Tertiary amides have most easily interpretable mass psectra which indicate the position of the double bond in the fatty acid chain. The pyrrolidide is advantageous for fatty acid gas liquid chromatography and mass spectrometry analyses because it can be prepared easily in high yield on a microscale, it is volatile enough for gas liquid chromatographic separations, and it has a simple and easily interpretable mass spectrum which indicates the structure.
Induction of essential fatty acid deficiency in mouse brain: Effects of fat deficient diet upon acyl group composition of myelin and synaptosome‐rich fractions during development and maturation
Authors: Sun G. Y. , Go J. , Sun A. Y.
Published: December 2006

A fat‐deficient diet was initiated in mice before birth and at different ages during development and maturation. The induction of an essential fatty acid deficiency in brain was most effective when the deficient diet was initiated prenatally. With increasing time on the deficient diet, there was an increase in 20∶3(n−9) and a decrease in 20∶4(n−6) in the phosphoglycerides of subcellular brain fractions. The highest ratio of 20∶3(n−9) to 20∶4(n−6) observed was 1.5 for both diacyl and alkenylacyl glycerophosphorylethanolamines in the synaptosome‐rich fraction from mice on the deficient diet from before birth to 7 months of age. The acyl groups of brain ethanolamine plasmalogens are quite susceptible to alteration by the fat‐deficient diet. Elongated products of 20∶3(n−9), tentatively identified as 22∶3(n−9) and 22∶5(n−9), also were present in brain during essential fatty acid deficiency. These fatty acids were preferentially linked to the alkenylacyl glycerophosphorylethanolamines. It further was observed that, even when the deficient diet was initiated after maturation, similar changes in fatty acid composition occurred in both myelin and synaptosomerich fractions, but at a slower rate. For mice on the deficient diet from 12–18 months of age, the highest ratio of 20∶3(n−9) to 20∶4(n−6) was 0.6 for the alkenylacyl glycerophosphorylethanolamines from the myelin.