bluuebunny/crossref_metadata_2025_split huggingface dataset:
Monohexosylceramides of larval and adult forms of the tapeworm,spirometra erinacei
Authors: Kawakami Yasushi , Kojima Hisako , Nakamura Kazuo , Suzuki Minoru , Uchida Akihiko , Murata Yoshihiko , Tamai Yoichi 
Published: November 2006

AbstractThe occurrence of glycosphingolipids with unique carbohydrate structures in different species of cestode, Platyhelminth, which had been shown, previously, prompted us to study the molecular species of the monohexosylceramides (cerebrosides) in the pseudophyllidean cestode,Spirometra erinacei. The purpose of the study was to obtain a basis for future investigations of the physiological role of glycolipids in parasitism. Cerebrosides were isolated froms. erinacei at two growth stages, i.e., from the larval form (plerocercoid) and from the adult tapeworms (intestinal form). The cerebrosides were separated into four subfractions by silica gel column chromatography, and their constituents were analyzed by gasliquid chromatography, gas chromatography/mass spectrometry, and high‐performance liquid chromatography/mass spectrometry. The hexoses of the cerebrosides consisted primarily of galactose in both growth stages, while only a small amount of glucose was detected. The ceramides were composed of sphinganine (d18∶0) and phytosphingosine (t18∶0) as sphingoid bases, and of nonhydroxy fatty acids ranging from C16 to C30 and hydroxy stearic acid (18h∶0). The cerebrosides of adult tapeworms contained more 18h∶0 than those of plerocercoids. The combination of hexoses and ceramides in the cerebroside molecules was slightly different in the two growth stages: the glucocerebrosides of plerocercoids contained only d18∶0‐nonhydroxy fatty acids in their ceramide moieties, whereas those of adult tapeworms contained varying ceramide moieties. Our data indicate that the molecular species of glycolipids present were essentially homeostatic throughout growth in spite of the entirely different environmental conditions, although there were slight differences in the hexose distribution in the two growth stages.
The structure of the core polyol of the ether lipids fromSulfolobus acidocaldarius
Authors: Sugai Akihiko , Sakuma Rie , Fukuda Ikuko , Kurosawa Norio , Itoh Yuko H. , Kon Kazuo , Ando Susumu , Itoh Toshihiro 
Published: November 2006

AbstractThe major ether‐type lipid structures ofSulfolobus acidocaldarius (ATCC33909) were composed of caldarchaeol and calditoglycerocaldarchaeol. However, the characterization by nuclear magnetic resonance spectroscopy and mass spectrometry showed that the structure of calditol in calditoglycerocaldarchaeol is not nonitol, 2‐(1′,2′,3′‐trihydroxypropyl)1,2,3,4,5,6‐hexahydroxyhexane, but 2‐hydroxymethyl‐1‐(2,3‐dihydroxypropoxy),2,3,4,5‐cyclopentanetetraol with an ether linkage in the molecule. Such an intermolecular ether linkage was resistant, to BCl3 treatment, but nonresistant to 57% HI degradation treatment conducted at 100°C for 60 h, producting 2‐hydroxymethyl‐1,2,3,4,5‐cyclopentanepentaol from calditol as reaction product. Further, it was confirmed that the structure of calditol is essentially a derivative of glycerol, and hydrocarbon chains were conjugated to the glycerol‐like site in the structure. The calditol with an ether linkage in the molecule suggested an important role regarding the properties of heat‐resistance and acid‐resistance observed inSulfolobales.
Role of cyclic adenosine monophosphate in phospholipid synthesis inMycobacterium smegmatis ATCC 607
Authors: Kaur Harpinder , Khuller G. K. 
Published: November 2006

AbstractThe present study was undertaken to examine the influence of intracellular levels of cyclic AMP on phospholipid synthesis inMycobacterium smegmatis ATCC 607. The cyclic AMP levels were modulated by growing cells in the presence of activator (forskolin) and inhibitor (atropine) of adenylate cyclase, the synthesizing enzyme of cyclic AMP. Forskolin‐grown cells exhibited a 1.4‐fold increase in the level of cAMP while a similar decrease (1.8‐fold) was seen with atropine‐grown cells. These altered levels of cAMP in turn affected the total content, composition and synthesis of phospholipids. Total phospholipid content increased and decreased in cells grown in the presence of forskolin and atropine, respectively. These observations were further supported by alterations in [14C]acetate incorporation as well as in activities of glycerol kinase and glycerol‐3‐phosphate acyltransferase, the key enzymes of phospholipid synthesis. Protein phosphorylation mechanism seems to be involved in phospholipid metabolism as the activities of protein kinase increased and decreased in cells grown in forskolin or atropine cells. Our results demonstrate a correlation between phospholipid synthesis and intracellular levels of cAMP inM. smegmatis.
Purification and properties of an extracellular lipase from the fungusBotrytis cinerea
Authors: Comménil Pascal , Belingheri Lionel , Sancholle Michel , Dehorter Bertrand 
Published: November 2006

AbstractAn extracellular lipase (EC 3.1.1.3) from the fungusBotrytis cinerea has been purified to homogeneity and characterized. The purification included ammonium sulfate fractionation and sequential column chromatography. The purification of the preparation was 31‐fold and recovery yield was 21%. The purified enzyme was associated with esterase activity according to activity staining on polyacrylamide gel. The molecular weight was determined as 60 kDa on sodium dodecyl sulfate‐polyacrylamide gel electrophoresis and estimated at 72 kDa using gel filtration, which suggests that the enzyme may be a monomer. The isoelectric point was 6.5, and optimal activity was obtained at 38°C and pH 6.0. This lipase showed a high specificity for synthetic substrates containing long‐chain unsaturated fatty acids using umbelliferone esters. The effect of β‐cyclodextrin on the hydrolysis of olive oil has been studied. The specific activity was 25 μmole/min/mg in the absence of β‐cyclodextrin and 132 μmole/min/mg in its presence.
Fatty acid composition of erythrocyte, platelet, and serum lipids in strict vegans
Authors: Ågren Jyrki J. , Törmälä Marja‐Leena , Nenonen Mikko T. , Hänninen Osmo O. 
Published: November 2006

AbstractThe fatty acid composition of erythrocytes, platelets, and serum lipids was compared between subjects who had been eating a strict uncooked vegan diet (“living food”) for years and omnivore controls. The vegan diet contains equal amounts of fat but more monounsaturated and polyunsaturated and less saturated fatty acids than the mixed diet of the control group. In vegans, the proportion of linoleic acid was greater in all lipid fractions studied. Also, the levels of other n−6 fatty acids were greater, with the exception of arachidonic acid levels, which were similar in most fractions. In erythrocytes, platelets and serum phospholipid fractions, this increase was mainly at the expense of the n−3 fatty acids. The proportions of eicosapentaenoic and docosahexaenoic acid were only 29–36% and 49–52% of those in controls, respectively. In vegans the ratio of n−3 to n−6 fatty acids was only about half that in omnivores. In addition to the lower levels of n−3 fatty acids, the proportions of palmitic and stearic acids were lower in serum cholesteryl esters, triglycerides and free fatty acids of vegans. The proportion of oleic acid was slightly lower only in serum cholesteryl esters and erythrocyte phosphatidylserine. The results show that, in the long term, the vegan diet has little effect on the proportions of oleic and arachidonic acids, whereas the levels of n−3 fatty acids are depressed to very low levels with prolonged consumption of the high linoleic and oleic acid components of this diet.
Characterization of the diacylglycerol acyltransferase activity in the membrane fraction from a fungus
Authors: Kamisaka Yasushi , Yokochi Toshihiro , Nakahara Toro , Suzuki Osamu 
Published: November 2006

AbstractIn an attempt to clarify the mechanism of lipid accumulation inMortierella ramanniana var.angulispora, diacylglycerol acyltransferase (DGAT) in the membrane fraction from this fungus was characterized. The enzyme had an optimum pH of 7.0–7.5, and enzyme activity was blocked by SH‐reagents. Metal ions were not essential for maintaining DGAT activity.n‐Octyl‐β‐d‐glucoside, 3‐[(3‐cholamidopropyl)dimethylammonio]‐1‐propanesulfonate and Tween 80 were found to preserve activity, while Triton X‐100 and sucrose monolaurate inhibited it. As the inhibition of DGAT activity by Triton X‐100 was overcome by the addition of diacylglycerol (DG), the dependency of DGAT activity on exogenous DG was determined in the presence of 0.1% Triton X‐100. DGAT activity in the membrane fraction was traced in fungi cultured for different time periods or in media at different carbon to nitrogen (C/N) ratios. Although the increase in total lipid content with culture time was accompanied by an increase in DGAT activity, total lipid changes related to changes in C/N ratio did not correlate with DGAT activity. Factors other than DGAT activity in the membrane fraction would appear to be involved in the regulation of total lipid content in this fungus.
Atherosclerosis and plasma and liver lipids in nine inbred strains of mice
Authors: Nishina Patsy M. , Wang Jiajin , Toyofuku Wendy , Kuypers Frans A. , Ishida Brian Y. , Paigen Beverly 
Published: November 2006

AbstractNine inbred strains of mice, which are progenitors of recombinant inbred sets, were evaluated for aortic lesion formation and plasma and liver lipid levels. This survey was done to determine if a semi‐synthetic high‐fat diet could elicit the same extent of diet‐induced atherosclerosis as that observed in mice fed a natural ingredient highfat diet and to discover strain‐specific plasma and liver lipid variants for future genetic characterization. Evaluation of aortic lesions after 18 wk of diet consumption showed that strains C57BL/6J, C57L/J, SWR/J and SM/J were susceptible to atherosclerosis and that A/J, AKR/J, C3H/HeJ, DBA/2J and SJL/J were relatively resistant. High‐density lipoprotein cholesterol (HDL‐C) levels were negatively correlated to lesion formation. Susceptible strains had decreased HDL‐C levels when switched from chow to the semi‐synthetic high‐fat, high cholesterol diet, whereas resistant strains either showed no change or a slight increase in HDL‐C levels. The exception to this pattern was found in SM mice, which were susceptible to aortic lesion formation but maintained the same HDL‐C level on both chow and high‐fat diets. HDL size differed among the strains, and levels of plasma apolipoprotein A‐I and A‐II correlated with HDL‐C levels. Liver damage was not correlated to HDL‐C levels or to susceptibility to atherosclerosis. Mice from strain A, which are resistant to atherosclerosis, had evidence of liver damage as observed by elevated levels of plasma alanine aminotransferase activity, by liver histology, by increased liver weight and by exceptionally high hepatic cholesterol content. For all strains, the levels of liver cholesterol and triglycerides were inversely correlated with each other; phospholipids did not vary greatly among strains. No remarkable differences in hepatic fatty acid profile were noted among the strains fed the atherogenic diet, but the fatty acid profile did differ considerably from that found in the diet itself.
The esterification of cholesterol in the yolk sac membrane of the chick embryo
Authors: Shand J. H. , West D. W. , McCartney R. J. , Noble R. C. , Speake B. K. 
Published: November 2006

AbstractThe uptake of lipid from the yolk by the yolk sac membrane of the chick embryo is accompanied by the rapid esterification of a large proportion of the yolk cholesterol. This could arise from enhanced acyl‐CoA:cholesterol acyltransferase (ACAT) activity and/or inhibition of cholesteryl ester hydrolase (CEH) activity. The activity of ACAT was therefore measured in microsomes obtained from yolk sac membranes at various stages of development. A high level of activity (up to 929 pmol of cholesteryl oleate formed per min per mg protein) was found during the second half of this period. Supplementation with exogenous cholesterol stimulated ACAT activity in microsomes obtained from the tissue at the earlier, but not at the later, stages of development suggesting that the enzyme became saturated with microsomal cholesterol as development proceeded. Correlating with this, the concentration of cholesterol in the microsomes increased 4‐fold between 9 and 20 d of development. The activity of CEH was very low in the microsomes and could not be detected in the cytosolic fraction. The activity of a protein, which has been shown to function as an inhibitor of CEH, was found to be present at all stages of development. The high activity of ACAT, together with the low activity of CEH and an active CEH inhibitor protein is a combination well suited to promote an essentially unidirectional conversion of cholesterol to cholesteryl ester. This process may be a major determinant of the rate of lipid transfer from the yolk to the embryo.
Triacylglycerol structure of human colostrum and mature milk
Authors: Martin Jean‐Charles , Bougnoux Philippe , Antoine Jean‐Michel , Lanson Monique , Couet Charles 
Published: November 2006

AbstractBecause triacylglycerol (TAG) structure influences the metabolic fate of its component fatty acids, we have examined human colostrum and mature milk TAG with particular attention to the location of the very long chain polyunsaturated fatty acid on the glycerol backbone. The analysis was based on the formation of various diacylglycerol species from human milk TAG upon chemical (Grignard degradation) or enzymatic degradation. The structure of the TAG was subsequently deduced from data obtained by gas chromatographic analysis of the fatty acid methyl esters in the diacylglycerol subfractions. The highly specific TAG structure observed was identical in mature milk and colostrum. The three major fatty acids (oleic, palmitic and linoleic acids) each showed a specific preference for a particular position within milk TAG: oleic acid for thesn‐1 position, palmitic acid for thesn‐2 position and linoleic acid for thesn‐3 position. Linoleic and α‐linolenic acids exhibited the same pattern of distribution and they were both found primarily in thesn‐3 (50%) andsn‐1 (30%) positions. Their longer chain analogs, arachidonic and docosahexaenoic acids, were located in thesn‐2 andsn‐3 positions. These results show that polyunsaturated fatty acids are distributed within the TAG molecule of human milk in a highly specific fashion, and that in the first month of lactation the maturation of the mammary gland does not affect the milk TAG structure.
Dietary saturated, monounsaturated, n−6 and n−3 fatty acids, and cholesterol influence platelet fatty acids in the exclusively formula‐fed piglet
Authors: Innis Sheila M. , Dyer Roger , Wadsworth Louis , Quinlan Paul , Diersen‐Schade Deborah 
Published: November 2006

AbstractPlatelet lipid composition is important to normal platelet morphology and function, and is influenced by dietary fatty acids and cholesterol. The fatty acid composition and cholesterol content of infant formulas differs from those of human milk, but the possible effects on platelet lipids in young infants is not known. This was studied in piglets fed from birth to 18 d of age with one of eight formulas differing in saturated fatty acid chain length, or content of 18∶1, 20∶5n−3 plus 22∶6n−3, or cholesterol. A reference group of piglets fed sow milk was also studied. Sow milk has a fatty acid composition and cholesterol content similar to that of human milk. Piglets fed formulas high in 18∶1 (34.9–40.8% wt fatty acids) and low in 16.0 (≤6.5% wt fatty acids) had lower platelet counts and greater platelet size than piglets fed sow milk (40.4% 18∶1, 30.7% 16∶0). Piglets fed formulas high in 16∶0 (27–29.6%) and 18∶1 (40–40.6%), or low in both 16∶0 (5.9–6.1%) and 18∶1 (10.8–11.2%), had similar platelet counts and size to piglets fed sow milk. Platelet phospholipid % 20∶4n−6 was lower in all the groups of piglets fed formula than in the group fed sow milk. Addition of fish oil with 20∶5n−3 plus 22∶6n−3 to the formula further decreased platelet phospholipid 20∶4n−6. Addition of cholesterol to the formula increased the platelet phospholipid % 20∶4n−6 and platelet volume.
Rat vitamin E status and heart lipid peroxidation: Effect of dietary α‐Linolenic acid and marine n−3 fatty acids
Authors: Javouhey‐Donzel Anne , Guenot Lucien , Maupoil Véronique , Rochette Luc , Rocquelin Gérard 
Published: November 2006

AbstractThree groups of sixteen male rats each were fed semipurified diets containing 15% by weight of lipid for a period of 4 wk. The diets contained the same amount of polyunsaturated fatty acids (PUFA) (20% of total fatty acids) and saturated fatty acids (19% of total fatty acids). Dietary PUFA were represented exclusively by linoleic acid (18∶2 diet), or 10% linoleic acid and 10% linolenic acid (18∶3 diet), or 10% linoleic acid and 10% long‐chain n−3 fatty acids (LCn−3 diet). The overall amount of vitamin E was similar in the three diets,i.e, 140, 133 and 129 mg/kg diet, respectively. Following appropriate extraction, tocopherol levels in heart, liver, brain, adipose tissue (AT) and plasma were measured by high‐performance liquid chromatography. The level of vitamin E in the heart decreased with n−3 PUFA diets, most markedly with LCn−3 PUFA. Liver and AT vitamin E contents also decreased with n−3 PUFA diets when expressed as μg/mg total lipids and μg/mg phospholipids, respectively. Total plasma vitamin E was lower in rats fed the LCn−3 diet, but there was no significant difference when expressed as μg/mg total lipids. Brain vitamin E was not affected by the various diets.In vitro cardiac lipid peroxidation was quantified by the thiobarbituric acid reactive substances (TBARS) test. Heart homogenates were incubated at 37°C for 15 and 30 min in both the absence (uninduced) or presence (induced) of a free radical generating system (1 mM xanthine, 0.1 IU per mL xanthine oxidase, 0.2 mM/0.4 mM Fe/ethylenediaminetetraacetic acid). TBARS release was time‐independent but significantly higher when LCn−3 fatty acids were fed to rats in either the uninduced or induced system. The study demonstrated that n−3 PUFA diets can influence vitamin E status of rats even in short‐term experiments and can change the susceptibility of the heart toin vitro lipid peroxidation.
A multivariate optimization of triacylglycerol analysis by high‐performance liquid chromatography
Authors: Bergqvist Magnus H. J. , Kaufmann Peter 
Published: November 2006

AbstractIn the present study we have used statistical experimental design and multivariate optimization to formally optimize a reversed‐phase high‐performance liquid chromatography method for the analysis of triacylglycerol molecular species of natural oils. The optimal conditions found were, on an octadecylsilan‐column, from acetonitrile/isooctane (90∶10, vol/vol) to acetonitrile/ethanol/isooctane (40∶35∶25, by vol), at a column temperature of 50°C and a flowrate of 1.5mL/min using a negative exponential gradient profile. Several examples of separations of natural seed and animal oils,i.e., soybean oil, rapeseed oil, palm oil, linseed oil, tallow and fish oil, are given. A version of the equivalent carbon number concept, utilizing the Snyder polarity index, was used to identity the molecular species.
Regio‐ and stereochemical analysis of trihydroxyoctadecenoic acids derived from linoleic acid 9‐ and 13‐hydroperoxides
Authors: Hamberg Mats 
Published: November 2006

AbstractThe methyl esters of 9S,10S,13R‐trihydroxy‐11E‐octadecenoic acid, 9S,10R,13S‐trihydroxy‐11E‐octadecenoic acid, and 9S,10R,13R‐trihydroxy‐11E‐octadecenoic acid were prepared from 9S‐hydroperoxy‐10E,12Z‐octadecadienoic acidvia the epoxy alcohols methyl 10R,11R‐epoxy‐9S‐hydroxy‐12Z‐octadecenoate and methyl 10S,11S‐epoxy‐9S‐hydroxy‐12Z‐octadecenoate. The trihydroxyesters, as well as four stereoisomeric methyl 9,12,13‐trihydroxy‐10E‐octadecenoates earlier prepared [Hamberg, M.,Chem. Phys. Lipids 43, 55–67 (1987)], were characterized by thin‐layer chromatography, gas‐liquid chromatography, mass spectrometry, and by chemical degradation. Availability of these chemically defined trihydroxyoctadecenoates made it possible to design a method for regio‐ and stereochemical analysis of 9,10,13‐ and 9,12,13‐trihydroxyoctadecenoic acids obtained from various sources. Application of the method revealed that the mixture of 9,10,13‐ and 9,12,13‐trihydroxyoctadecenoic acids formed during autoxidation of linoleic acid in aqueous medium contained comparable amounts of the sixteen possible regio‐ and stereoisomers. Furthermore, hydrolysis of the allylic epoxy alcohol, methyl 9S,10R‐epoxy‐13S‐hydroxy‐11E‐octadecenoate, yielded a major trihydroxyoctadecenoate,i.e., methyl 9S,10S,13S‐trihydroxyl‐11E‐octadecenoate, together with smaller amounts of methyl 9S,10R,13S‐trihydroxy‐11E‐octadecenoate, methyl 9S,12R,13S‐trihydroxy‐10E‐octadecenoate, and methyl 9S,12S,13S‐trihydroxy‐10E‐octadecenoate.
Comparative specificity of plasma lecithin: Cholesterol acyltransferase from ten animal species
Authors: Grove Douglas , Pownall Henry J. 
Published: November 2006

AbstractThe molecular specificities of plasma lecithin:cholesterol acyltransferase (LCAT) from ten animal species have been compared. Using a reassembled high density lipoprotein containing a mixture of phosphatidylcholines, the relative rates of liberation of different species of cholesteryl ester were measured. All but two species of LCAT clustered according to one of three patterns of substrate specificity. The LCAT from six species, including human, did not transfer highly polyunsaturated fatty acyl chains. In addition, human LCAT transesterified saturated fatty acyl chains more effectively than unsaturated fatty acyl chains. We conclude that the structures of the active sites of the enzymes differ, and that this may be related to size constraints that prevent efficient binding of large bulky phosphatidylcholines.
Activation and solubilization by triton X‐100 of membrane‐bound phospholipase D of rat brain
Authors: Kanoh Hiroyuki , Kanaho Yasunori , Nozawa Yoshinori 
Published: November 2006

AbstractIn the present study, we examined the ability of detergents to stimulate and solubilize phospholipase D (PLD) of a particulate fraction of rat brain. PLD activity was assayed by measuring the [3H]choline produced from the exogenous substrate dipalmitoyl phosphatidyl[3H]choline (dipalmitoyl [3H]PC). In the absence of detergents, PLD activity was not detectable. Of the detergents examined, Triton X‐100 was found to markedly enhance PLD activity, whereas other detergents including sodium doexycholate, sodium cholate, CHAPS and Lubrol‐PX caused only a small, if any increase in activity. Enhancement by Triton X‐100 was maximal at 0.1–0.2% (w/v) and decreased at higher concentrations. The optimal pH was 7.1–7.3. Both Ca2+ and Mg2+ inhibited enzyme activity stimulated by Triton X‐100 in a concentration‐dependent manner. Triton X‐100 effectively solubilized PLD from the particulate fraction of rat brain; more than 70% of the activity of the particulate fraction was extracted by 0.5–1.0% (w/v) Triton X‐100. Furthermore, when the PLD activities in brains of three different species (rat, rabbit and bovine) were measured under optimal conditions, the activities were found to differ greatly. PLD activity was highest in rabbit brain, followed by rat and bovine brains; the activity in bovine brain was extremely low compared to the activities in rat and rabbit brains. We conclude that Triton X‐100 is potentially useful for the purification of PLD and that rabbit and rat brains are the preferred sources.