bluuebunny/crossref_metadata_2025_split huggingface dataset:
Occurrence of a novel sterol, 24,25‐methylenecholest‐5‐en‐3β‐ol, inMortierella alpina 1S‐4
Authors: Shimizu Sakayu , Kawashima Hiroshi , Wada Masaru , Yamada Hideaki 
Published: November 2006

Abstract24,25‐Methylenecholest‐5‐en‐3β‐ol, which has not been reported previously to exist in nature, was isolated from mycelia of an arachidonic acid‐producing fungus,Mortierella alpina 1S‐4. Desmosterol, ergosta‐5,24(25)‐dien‐3β‐ol and ergosta‐5,25‐dien‐3β‐ol were also found in the fungus, but ergosterol and cholesterol were not detected.
Effect of different acids with Δ9,12‐dienoic structures on Δ9 desaturation activity in rat liver microsomes
Authors: de Alaniz Maria J. T. , de Gomez Dumm Irma N. T. , Brenner Rodolfo R. 
Published: November 2006

AbstractThe effect of oral administration, for 24 or 48 hr, of different octadeca fatty acids containing a 9,12‐dienoic structure on the fatty acid composition and Δ9 desaturation activity of liver microsomes of rat fed a fat‐free diet was studied. The ethyl esters of linoelaidic and γ‐linolenic acids, the methyl ester of linoleic acid and free columbinic acid were administered to rats maintained on a fat‐free diet. The supplementation of the fat‐free diet with linoelaidate produced no relevant changes in the fatty acid composition pattern of liver microsomes and did not modify the percentage of conversion of palmitic to palmitoleic acid. The addition of linoleate or γ‐linolenate to the fat‐free diet returned liver microsome Δ9 desaturation activity toward the control and partially restored the liver microsome fatty acid spectrum found in the fat‐free diet. Columbinic acid (5‐trans‐9‐cis,12‐cis‐18∶3), which cannot be transformed into arachidonic acid, also decreased the Δ9 desaturation activity enhanced by the fat‐free diet and evoked changes in the microsomal fatty acid composition similar to those produced by the ω6 fatty acids. These results suggest that the modulation of Δ9 desaturase activity evoked by dietary administration of unsaturated acids of ω6 series would depend on thecis double bond configuration of these acids.
Fatty acids in crinoidea and ophiuroidea: Occurrence of all‐cis‐6,9,12,15,18,21‐tetracosahexaenoic acid
Authors: Takagi Toru , Kaneniwa Masaki , Itabashi Yutaka 
Published: November 2006

AbstractThe fatty acid compositions of lipids from two species of Crinoidea and two species of Ophiuroidea have been investigated with open‐tubular gas chromatography. About 5–10% of tetracosahexaenoic acid was found in total fatty acids from all the samples, and the structure was determined as all‐cis‐6,9,12,15,18,21‐tetracosahexaenoic acid [24∶6(n−3)] by13C‐NMR of the methyl esters and mass spectrometric analyses of the methyl esters, the pyrrolidides and the ozonolysis products. The 24∶6(n−3) was concentrated in the polar lipids rather than neutral lipids. The n−3 hexaenoic structure suggested chain elongation of 22∶6(n−3) as the source.The 5‐olefinic acids (5−18∶1, 5−20∶1, 5,11‐ and 5,13−20∶2) were low in Crinoidea (0.2–1.3%) but were present in higher levels (2.5–5.2%) in Ophiuroidea. Polyunsaturated acids found other than 24∶6(n−3) were 20∶4(n−6), 20∶5(n−3) and 22∶6(n−3) as major components and 16∶3(n−3), 18∶2(n−6), 18∶3(n−6), 18∶3(n−3), 18∶4(n−3), 20∶2(n−9), 20∶2(n−6), 20∶3(n−6), 20∶3(n−3), 21∶5(n−3) and 22∶5(n−3) as minor components in all the samples.
Effects of estradiol and environmental temperature changes on rat liver Δ6 microsomal desaturase activity
Authors: Gonzalez Susana , Nervl Anibal M. , Peluffo Raul O. 
Published: November 2006

AbstractThe regulation of Δ6 desaturase activity by environmental temperature changes was studied in the microsomal membranes from female and ovariectomized female rat liver. Female rats adapted at 30–32 C for 20–25 days and then shifted to 13–15 C for 5 days showed an increased Δ6 desaturase system. Ovariectomized rats adapted under the same conditions did not show significant changes in this enzyme. The fatty acid compositions of microsomal phosphatidylcholine showed a decrease in arachidonic acid in female rats at 30 C compared to females at 15 C and ovariectomized rats at both temperatures. These results suggest that a modification of ovaric sex hormone levels might be responsible for the different Δ6 desaturase activity in female rats acclimated at both temperatures. In this regard, serum estradiol radioimmunoassay yielded slight differences between the two groups of female rats, suggesting that estradiol could play a role in the regulation of the Δ6 desaturase. The administration of a pharmacological dose of 17‐β estradiol to female and ovariectomized rats kept at 30 and 15 C decreased the Δ6 microsomal desaturase activity. These data suggest that estradiol levels are involved in the regulation of the Δ6 desaturase during cold adaptation.
Metabolism and incorporation into glycerolipids of exogenous 18∶3(n−3) and 18∶3(n−6) by MDCK cells
Authors: Lynch Robert D. , Locicero Jean , Schneeberger Eveline E. 
Published: November 2006

AbstractThe extent to which exogenous 18∶3(n−3) and 18∶3(n−6) were desaturated and elongated and the degree to which they and their derivatives altered the unsaturation index of cell glycerolipids were compared using clone 4 MDCK cells grown in lipid‐ and serum‐free medium. Despite differences in the degree of unsaturation of the individual polyunsaturated fatty acids produced from 18∶3(n−3) or 18∶3(n−6), the unsaturation index of phospholipids increased similarly from 0.7 in control cells grown in serum‐ and lipid‐free medium to ca. 1.6 in those supplemented with fatty acid. The added fatty acids had little effect on cell growth. The conversion of 18∶3(n−6) to 20∶3(n−6) and 20∶4(n−6) was more rapid than that of 18∶3(n−3) to 20∶4(n−3) and 20∶5(n−3). No significant quantities of 20∶3(n−3) or 18∶4(n−3) were noted. When both 18∶3 isomers were supplied simultaneously, marked differences in the amounts of some species of n−3 and n−6 polyunsaturated fatty acids were observed. The presence of 18∶3(n−6) and/or its derivatives suppressed levels of 20∶4(n−3) and 20∶5(n−3), perhaps through inhibition of the Δ6 and Δ5 desaturases responsible for their synthesis from 18∶3(n−3). Similarly 18∶3(n−3), and/or its longer more unsaturated derivatives, diminished the formation of 20∶4(n−6) from 18∶3(n−6). No marked effect on the products derived from elongation alone were observed.
Effect of nutritional status on the fatty acid composition of rat liver and cultured hepatocytes
Authors: Nelson Gary J. , Kelley Darshan S. , Hunt James E. 
Published: November 2006

AbstractThe lipid concentration and fatty acid composition of the whole liver and of cultured hepatocytes isolated from the livers of rats fed ad libitum (fed), fasted for 24 hr (fasted), or fasted for 48 hr and then refed a fat‐free, high carbohydrate diet for 48 hr (refed) was studied. Hepatocytes were maintained as monolayer cultures in serum‐free, lipid‐free media and their fatty acid composition was analyzed at 3, 24, 48, 72 and 96 hr. The livers of fed animals, as well as their hepatocytes, contained less total lipid than those from animals on either of the other dietary regimes. Livers of fasted animals had three times the amount of lipid found in the livers of fed animals, and the livers of refed animals contained five times the amount of lipid as the livers of fed animals (all based on mg lipid/g wet weight of liver). The fatty acid composition of hepatocytes after 3 hr of culturing was very similar to that of fresh liver when compared in each of the dietary regimes. However, while the fatty acid compositions of livers and hepatocytes from fed and fasted animals were similar, the pattern in liver of refed animals was quite distinct from that of the fed animals. In the fed and fasted animals palmitic acid (16∶0), stearic acid (18∶0), oleic acid (18∶1[n‐9]), linoleic acid (18∶2[n‐6]) and arachidonic acid (20∶4[n‐6]) were the major fatty acids of the liver; in refed animals 16∶0, palmitoleic acid (16∶1[n‐7]), 18∶0, 18∶1(n‐9) andcis‐vaccenic acid (the n‐7 isomer of oleic acid) were the major fatty acids. During maintenance in culture the 18∶1(n‐9) content of the hepatocytes increased in cells from livers of animals on all three dietary regimes. The polyunsaturated fatty acid content was similar in fresh livers and isolated hepatocytes in all samples when compared on the basis of μg fatty acid/mg of hepatocyte or liver protein. It was also found that the polyunsaturated fatty acid content of hepatocytes was remarkedly stable with time of culture when the cells were incubated in serum‐free, lipid‐free medium. Thus, isolated hepatocytes maintained in serum‐free medium appear to be a possible system for the evaluation of the effects of prior nutritional status on fatty acid metabolism in the whole animal, not subject to hormonal and other somatic influences which often complicate the interpretation of such nutritional studies.
Glycerolipid biosynthesis in rat adipose tissue. Influence of age and cell size on substrate utilization
Authors: Jamdar Subhash C. , Osborne Linda J. , Wells Gary N. 
Published: November 2006

AbstractThe conversion of [14C]‐labeled compounds such as acetate, glucose, pyruvate and palmitate into CO2, glyceride‐glycerol, glyceride fatty acids and total lipids was monitored in the average and matching adipocyte (with respect to size) preparations from young (6–9 wk) and old (age 56–60 wk) male Sprague‐Dawley rats. The average cell size populations from young and old rats were 46±3 and 83±11 μm in diameter, respectively. The incorporation of [14C]acetate, pyruvate and glucose into fatty acids was significantly reduced in the adipocytes from older rats, irrespective of their sizes. The production of CO2and glyceride‐glycerol did not change significantly as a function of either cell size or animal age. Palmitate incorporation into lipids was similar in the average cell population derived from old and young rats, but it was considerably lower in the smaller adipocytes (46–50 μm diameter) from old animals. Irrespective of the cell size, triacylglycerol formation fromsn‐glycerol‐3‐phosphate was also significantly diminished in the adipocytes from older animals compared to younger ones as evidenced by decreases in activities of several enzymes, includingsn‐glycerol‐3‐phosphate acyltransferase, Mg2+‐dependent phosphatidate phosphohydrolase and diacylglycerol acyltransferase. However, triacylglycerol formation from monoacylglycerol did not change as a function of either cell size or age. These measurements of the metabolic and enzymic activities provide evidence that the synthesis of fatty acids from various precursors and triacylglycerol formation fromsn‐glycerol‐3‐phosphate are significantly reduced in adipocytes from older animals and that such changes occur independently of adipocyte size.
Distribution of vitamins A and E in blood and liver of rats depleted of vitamin A or vitamin E
Authors: Omaye Stanley T. , Chow Faye I. 
Published: November 2006

AbstractYoung Sprague‐Dawley male rats (n=150) were fed a semipurified diet, either without vitamin A (VA), without vitamin E (VE) or supplemented with both vitamins A and E (control). At the end of weeks 0, 1, 3, 5, 6, 7, 8 and 9, groups of rats were anesthetized with methoxyflurane, and blood was collected by cardiac puncture until the rat was exsanguinated. The liver was excised. Whole blood (WB_ from each rat was fractionated into plasma (PLA), leukocytes (LEU), platelets (PLT) and erythrocytes (RBC). Each blood components was extracted with hepatane and livers were extracted with CHCl3/CH3OH (2∶1, v/v). The extracts were analyzed for VA and VE by high performance liquid chromatography. The relationship among blood components in the loss of VA was PLT=LEU>WB>PLA. The relationship among blood components in the loss of VE was PLA>RBC>WB>LEU‐PLT. VA and VE levels in other blood components decreased precipitously between weeks 0 and 4 in the animals placed on deficient diets. These results and correlation analyses between vitamin contents of blood components and of livers indicate inadequacies for the use of certain blood components as monitors of lipid‐soluble vitamin status in the rat.
Identification of 5,9‐hexadecadienoic acid in the marine spongeChondrilla nucula
Authors: Carballeira Nestor M. , Maldonado Lilliam 
Published: November 2006

AbstractThe fatty acid 5,9‐hexadecadienoic was identified in the spongeChondrilla nucula. This is the shortest fatty acid with the Δ5,9 unsaturation yet isolated from a marine sponge.
Mammary tumorigenesis in rats fed diets high in lard
Authors: Rogers A. E. , Conner B. , Boulanger C. , Lee S. 
Published: November 2006

AbstractStudies were performed to examine the effect of a lard diet on tumorigenesis by 7,12‐dimethylbenzanthracene (DMBA), given parenterally rather than by gavage, to eliminate any effect of the high lard diet on carcinogen absorption. In addition, the effect of low dietary levels of the antioxidants butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) in the tumor model was evaluated. The lards fed were analyzed for fatty acid composition and content of certain potential contaminants. DMBA induced tumors when given by intravenous or subcutaneous injection. The high lard diet appeared to enhance tumorigenesis in rats given a dose of 0.25 mg (10% of the gavage dose) by injection into the mammary gland, although the effect was not statistically significant. In other experiments using lard from different sources and DMBA given by gavage, significant enhancement of tumorigenesis was limited to groups fed the high lard diets throughout the experiment or beginning after DMBA exposure. In contrast to earlier results, there was no demonstrable effect of feeding the high lard diets before DMBA administration. Addition of BHA and BHT to the lard at the concentration assayed in commercial lard samples or at the maximum concentration permitted did not influence the tumorigenesis. In groups in which tumorigenesis was enhanced by the high lard diet, the incidence of malignant, invasive tumors was higher than in other groups.
Effect of dietary components on the pathobiology of colonic epithelium: Possible relationship with colon tumorigenesis
Authors: Bird R. P. 
Published: November 2006

AbstractThe concept that diet plays an important role in the initiation and/or development of various types of tumors in man and experimental animals is well documented. The etiology of colon cancer is complex and multifactorial in nature, and these is little information on the dietary components that may act as initiators during colon tumorigenesis. We have evaluated various dietary heterocyclic mutagenic amines present in a typical “Western” diet for their nuclear damaging effect (presumably a genotoxic response) on the colonic epithelium of C57BL/6J mice in vivo. Among the mutagenic amines studied, 2‐amino‐3,4‐dimethylimidazo(4,5‐f)quinoline and 2‐amino‐3‐methylimidazo(4,5‐f)quinoline were very potent inducers of nuclear aberrations. These observations provide us with clues that our daily diet may contain colon‐specific genotoxic components. Promotional effects of dietary fat and/or bile acids on colon tumorigenesis have been well studied. Dietary levels of calcium (0.1, 0.5 or 1.0% by weight) appear to modify the toxicity of orally administered fat or cholic acid (assessed by quantifying cell proliferation). The colons of animals consuming 0.1% or 0.5% calcium diet were more susceptible to the toxicity, whereas the colons of those consuming a 1.0% calcium diet appeared more like control colons. These studies demonstrate a profound effect of dietary constituents on the pathobiology of the colonic epithelium which may have a marked influence on the colon tumorigenesis.
A comparison of lipids from liver and hepatoma subcellular membranes
Authors: Wood Randall , Upreti Girish C. , de Antueno Roberto J. 
Published: November 2006

AbstractSubcellular fractions of nuclei, mitochondria, endoplasmic reticulum, plasma membrane and cytosol were prepared from liver and hepatoma 72288CTC. Marker enzyme activities, biochemical compositions and electron microscopy were used to establish purity. Hepatoma NADH: cytochrome C reductase and 5′‐nucleotidase exhibited abnormal subcellular distributions.The lipids from the subcellular fractions were examined in detail. Mitochondria and plasma membranes were characterized by elevated percentages of diphosphatidylglycrerol and sphingomyelin, respectively, in both tissues. All hepatoma subcellular fractions contained dramatically elevated levels of sphingomyelin and cholesterol, two components that form preferential strong complexes in vitro. The fatty acid composition of hepatoma sphingomyelin differed markedlg from liver and, unlike liver, did not exhibit organelle specific compositions. Some hepatoma lipid classes contained reduced percentages of palmitate while others contained higher levels. Hepatoma phosphatidylcholine and phosphatidylethanolamine from organelles contained lower percentages of long chain polyunsaturated fatty acids than liver. Generally, unique fatty acid profiles exhibited by individual phospholipid classes of liver subcellular fractions were absent or much reduced in the hepatoma. The ratios of oleate to vaccenate were near one for most of the phospholipid classes of most liver fractions, but all hepatoma classes, with few exceptions, contained a much higher percentage of oleate in all subcellular fractions. The hypothesis is proposed that the origin of some acyl moieties for the biosynthesis of various hepatome lipid classes differs from liver sources. The possible changes in acyl pools, sources and compartments for complex lipid biosynthesis could result in change in the quantities of molecular species that could contribute to the abnormal properties of the hepatoma membranes.
Molecular species composition of the major diacyl glycerophospholipids from muscle, liver, retina and brain of cod (Gadus morhua)
Authors: Bell M. V. , Dick J. R. 
Published: November 2006

AbstractThe molecular species composition of phosphatidylcholine (PC), phosphatidylethanolamine (PE) and phosphatidylserine (PS) from white muscle, liver, retina and brain of cod (Gadus morhua) were determined by high‐performance liquid chromatography of the respective 1,2‐diacylglycerol 3,5‐dinitrobenzoyl derivatives. A minimum of 69 diacyl species was identified. In muscle and liver saturated fatty acid/polyunsaturated fatty acid (PUFA) and monounsaturated fatty acid/PUFA molecular species were predominant, particularly 16∶0/20∶5 and 16∶0/22∶6 in PC, 16∶0/22∶6 and 18∶1/22∶6 in PE and 18∶0/22∶6 and 18∶1/22∶6 in PS. Didocosahexaenoyl species were major components of PC, PE and PS from retina, comprising 29.3, 71.8 and 59.7% of the respective totals. Didocosahexaenoyl species were also abundant in PE and PS from brain, accounting for 13.8 and 24.0% of the totals, respectively. DiPUFA species were important in muscle, totalling 21.2% in PC and 38.3% in PE. PC from all tissues had the largest amounts of species containing only saturated or monounsaturated fatty acids, accounting for 59.8% of PC from brain, including 12.8% of 18∶1/24∶1 plus 24∶1/18∶1.
Diacetone‐D‐glucosyl‐3‐O‐(N,N‐diethylamido)‐thiophosphates of the lipid‐soluble vitamins D2, D3 and E
Authors: Stamatov Stephan D. , Gronowitz Salo 
Published: November 2006

AbstractThe acyclic triamides of phosphorous acid, after appropriate activation, offer a number of advantages over conventional reagents when biologically active lipids are to be phosphorylated. The hexaethyltriamide of phosphorous acid activated by addition of iodine at the optimum molar ratio of 1.05∶0.05 was used as phosphorylating reagent to synthesize diacetone‐D‐glucosyl‐3‐0‐(N,N‐diethylamido)thiophosphates of ergocalciferol, cholecalciferol and DL‐α‐tocopherol in a “one‐pot” procedure in overall yields of 83–87%. The high selectivity of the phosphorylation at the monoester formation stage permits the direct synthesis of asymmetrical diesters. Anisochronicity was detected in the13C and31P nuclear magnetic resonance spectra of the thiophosphates synthesized. The compounds represent new types of glycophospholipid structures which, in addition to carbohydrate and a phosphagen fragment, contain a lipid‐soluble vitamin.
Involvement of heme components in sterol metabolism ofSaccharomyces cerevisiae
Authors: Lorenz R. Todd , Parks L. W. 
Published: November 2006

AbstractThere is an intimate association between sterol biosynthesis in yeast and aerobicity. Besides the requirement for molecular oxygen for the epoxidation of squalene, cytochrome hemoproteins are involved in demethylation and desaturation steps. Regulatory effects of hemes on sterol formation have been demonstrated using specifically defective mutants of yeast. Heme competency participates in a mechanism whereby wild‐type cells are prevented from taking exogenous sterols from the growth media. The multiple interactions of hemes and sterols appear to be associated with the variously defined functions for sterols in the yeast cells.
Free and combined sterols ofPavlova gyrans
Authors: Gladu Patricia K. , Patterson Glenn W. , Wikfors Gary H. , Lusby William R. 
Published: November 2006

AbstractPavlova gyrans, a unicellular alga of interest as food for oysters, was cultured axenically and examined for sterol composition. Desmethyl monohydroxy sterols, which are frequently seen in algae, made up 40% of the total sterols and were observed primarily in the free sterol fraction. The principal sterols of this group were 5‐ergostenol, poriferasterol, and clionasterol, as well as some poriferast‐22‐enol and poriferastanol. Several “methyl” sterols with unusual structures made up 27% of the total sterols. The principal “methyl sterols” were 4α‐methyl ergostanol, 4α‐methyl poriferastanol, and 4α‐methyl poriferast‐22‐enol. Methyl sterols were found primarily in the ester fraction. Also observed was a new class of dihydroxysterols composing 33% of the total sterols. These sterols are structurally related to the methyl and desmethyl sterols ofPavlova but contain an extra nuclear hydroxyl which can be acetylated when present on a desmethyl sterol, but which is nonreactive with acetic anhydride in 4α‐methyl sterols. None of these sterols were observed in ester form but are concentrated in the acid‐hydrolyzable, bound fraction. The unique nature of these sterols suggests potential taxonomic utility.
Sterols ofKalanchoe pinnata: First report of the isolation of both C‐24 epimers of 24‐alkyl‐Δ25‐sterols from a higher plant
Authors: Akihisa Toshihiro , Kokke W. C. M. C. , Tamura Toshitake , Matsumoto Taro 
Published: November 2006

AbstractEighteen sterols were isolated from the aerial parts ofKalanchoe pinnata (Crassulaceae) including four novel sterols,viz. (24R)‐stigmasta‐5,25‐dien‐3β‐ol (24‐epiclerosterol), (24R)‐5α‐stigmasta‐7,25‐dien‐3β‐ol, 5α‐stigmast‐24‐en‐3β‐ol, and 25‐methyl‐5α‐ergost‐24(28)‐en‐3β‐ol. 24‐Epiclerosterol and its Δ7‐analog occur together with their 24S/β‐epimers in the same plant making this the first report of the isolation of both C‐24 epimers of Δ25‐unsaturated 24‐alkylsterols from a non‐marine organism. Iodine‐catalyzed isomerization of stigmasta‐5,24‐dien‐3β‐ol (24‐ethyldesmosterol), the main sterol ofK. pinnata, yielded 24‐epiclerosterol among other products.
Occurrence and levels of ecdysteroids in spinach
Authors: Grebenok Robert J. , Ripa Perry V. , Adler John H. 
Published: November 2006

AbstractThe dominant ecdysteroid in spinach,Spinacia oleracea L., is 20‐hydroxyecdysone (2β,3β,14α, 20R,22R,25‐hexahydroxy‐5β‐cholest‐7‐en‐6‐one) with the presence of a smaller amount of polypodine B (2β,3β,5β,14α,20R,22R,25‐heptahydroxycholest‐7‐en‐6‐one). Ecdysteroids are present in the seed embryo at 14 μg ecdysteroid/seed, and ecdysteroid levels increase, in the plant during growth and development. During the onset of ecdysteroid production, the ratio of ecdysteroid to total sterol shifts from a value of one to about ten over the course of a week. Spinach may serve as a model to study ecdysteroid biosynthesis in plants.