bluuebunny/crossref_metadata_2025_split huggingface dataset:
Milk fat globules: Fatty acid composition, size and in vivo regulation of fat liquidity
Authors: Timmen Hermann , Patton Stuart 
Published: November 2006

AbstractPopulations of large and small milk fat globules were isolated and analyzed to determine differences in fatty acid composition. Globule samples were obtained by centrifugation from milks of a herd and of individual animals produced under both pasture and barn feeding. Triacylglycerols of total globule lipids were prepared by thin layer chromatography and analyzed for fatty acid composition by gas chromatography. Using content of the acids in large globules as 100%, small globules contained fewer short‐chain acids, −5.9%, less stearic acid, −22.7%, and more oleic acids, +4.6%, mean values for five trials. These differences are consistent with alternative use of short‐chain acids or oleic acid converted from stearic acid to maintain liquidity at body temperature of milk fat globules and their precursors, intracellular lipid droplets. Stearyl‐CoA desaturase (EC 1.14.99.5), which maintains fluidity of cellular endoplasmic reticulum membrane, is suggested to play a key role in regulating globule fat liquidity. Possible origins of differences between individual globules in fatty acid composition of their triacylglycerols are discussed.
6‐methyl‐8‐hexadecenoic acid: A novel fatty acid from the marine spongeDesmapsama anchorata
Authors: Carballeira Néstor M. , Maldonado Maria E. 
Published: November 2006

AbstractThe novel fatty acid 7‐methyl‐8‐hexadecenoic (1) was identified in the marine spongeDesmapsama anchorata. Other interesting fatty acids identified were 14‐methyl‐8‐hexadecenoic (2), better known through its methyl ester as one of the components of the sex attractant of the female dermestid beetle, and the saturated fatty acid 3‐methylheptadecanoic (3), known to possess larvicidal activity. The main phospholipid fatty acids encountered inD. anchorata were palmitic (16∶0), behenic (22∶0) and 5,9‐hexacosadienoic acid (26∶2), which together accounted for 50% of the total phospholipid fatty acid mixture.
Rhizomucor miehei triglyceride lipase is synthesized as a precursor
Authors: Boel Esper , Huge‐Jensen Birgitte , Christensen Mogens , Thim Lars , Fiil Niels P. 
Published: November 2006

AbstractARhizomucor miehie cDNA library constructed inEscherichia coli was screened with synthetic oligonucleotides designed from knowledge of a partial amino acid sequence of the secreted triglyceride lipase (triacyl‐glycerol acylhydrolase EC 3.1.1.3) from this fungus. Lipase‐specific recombinants were isolated and their insert sequenced. Unlike characterized bacterial and mammalian triglyceride lipases, the fungal enzyme is synthesized as a precursor, including a 70 amino acid residue propeptide between the 24 amino acid residues of the signal peptide and the 269 residues of the mature enzyme. The precursor processing mechanism, which involves cleavage between a methionine and a serine residue, is unknown. By sequence comparison with other lipases, a serine residue involved in substrate binding was identified in the fungal lipase. The sequence around this residue is well‐conserved among characterized lipases. Conservation of an intron in an isolated cDNA recombinant and immunoprecipitation of in vitro synthesizedR. miehei translation products indicates that the expression of the lipase gene might involve inefficient mRNA splicing.
Effects of hyperoxia and diet on murine tissue levels of vitamin E and polyunsaturated fatty acids
Authors: Tangney C. C. , McCloskey K. M. , Aye P. L. 
Published: November 2006

AbstractOne hundred eighty‐six adult female mice were studied to examine the effect of manipulating dietary vitamin E and fractional inspired oxygen concentrations (FiO2) on tissue levels of vitamin E, total polyunsaturated fatty acids (TPUFA) and conjugated dienes (CD) as an index of lipid peroxidation. Animals were fed custom diets containing either 0, 50 or 150 ppm DL‐α‐tocopheryl acetate. Once plasma vitamin E levels of mice fell below 0.2 mg/dl (at week 19), all mice were placed in chambers containing either room air (FiO2≈0.21) or FiO2>0.95 for the next 72 hr. Dietary manipulation had a major impact on the levels of vitamin E in plasma, lung and perirenal adipose tissues (p<0.0001, p<0.0001 and p<0.005, respectively). Dietary vitamin E deprivation was associated with significant reductions in lung glutathione peroxidase (GPX) activities (p<0.05) and in plasma TPUFA levels (p<0.05). No significant effect attributable to either diet or FiO2 was observed for liver vitamin E, liver TPUFA or lung TPUFA levels, or for those of CD in any tissue examined. Adipose TPUFA levels were depressed in all dietary groups exposed to FiO2>0.95, when compared with those of groups exposed to room air. The high FiO2 exposures also were associated with marked reductions in lung to body weight ratios (p<0.01). These data suggest that dietary vitamin E treatment after long‐term feeding can modify vitamin levels in plasma, lung and adipose tissue, and lung GPX activities. Vitamin E levels in liver seemed less responsive to our dietary manipulations in adult female mice, though expressing liver vitamin E levels in terms of TPUFA revealed significant differences between the ratios from 0 and 150 ppm vitamin E groups (p<0.05).
Trans fatty acids. 1. Growth, fertility, organ weights and nerve histology and conduction velocity in sows and offspring
Authors: Opstvedt Johannes , Pettersen Jan , Mork Sverre J. 
Published: November 2006

AbstractEffects of dietarytrans fatty acids on the pre‐ and postnatal growth and development in pigs were studied with special emphasis on nervous tissue. In experiment 1, female pigs were fed partially hydrogenated fish oil (PHFO) (28%trans) or soybean oil (PHSBO) (36%trans), in comparison with lard (0%trans) from weaning (3 wk) through the first reproduction cycle (up to 2 yr). In experiment 2, female pigs were fed two fish oils (33 and 19%trans) in comparison with coconut oil (0%trans) in diets with low and high levels of linoleic acid (18∶2n−6cis,cis) from gestation until their offspring were three wk old. Compared with thetrans‐free fats, thetrans‐containing fats had no effect on growth and development, feed consumption and utilization or on the weight of the brain, heart, kidneys, liver, lungs or spleen in the adult sows and their offspring. No effects from the experimental fats were found on histology and conduction velocity of the peroneal nerve. An increased number of the sows fed PHFO had fertility problems compared with those fed lard and PHSBO in Expt. 1, but no similar effects were seen in Expt. 2. It is concluded that consumption oftrans fatty acids with 18–22 carbon atoms from PHFO and with 18 carbon atoms from PHSBO at levels that were 5 to 12 times higher than those normally consumed by humans had no detrimental effects on female pigs or their offspring during pregnancy and lactation.
Lipids from the paracloacal glands of the American alligator (Alligator mississippiensis)
Authors: Weldon P. J. , Shafagati A. , Wheeler J. W. 
Published: November 2006

AbstractLipids from the paracloacal glands of adult and of immature American alligators (Alligator mississippiensis) were analyzed by gas chromatography‐mass spectrometry. Acetate esters (C12−C18) were indicated in the adults' secretions. Immature alligators contain C10−C18 acetates, C12−C18 dodecanoates, tetradecanoates and other high molecular weight esters, and C10−C16 3‐methyl‐butanoates. Cholesterol, C16 and C18 free fatty acids, and α‐tocopherol (vitamin E) were detected in some samples. The results are compared with those published for South American caiman species.
Lipid metabolic interrelationships and phospholipase activity in gustatory epithelium ofictalurus punctatus in vitro
Authors: Rabinowitz Joseph L. , Huque Taufiqul , Brand Joseph G. , Bayley Douglas L. 
Published: November 2006

AbstractThe catfish,Ictalurus punctatus, is an important model for studying the biochemical mechanisms of taste at the peripheral level. The type, amount and metabolic activity of the lipids within this tissue play important roles in taste transduction by forming the matrix in which the receptors for taste stimuli are imbedded and by acting as precursors to second messengers. The metabolic interconversions that occur among the lipids on the taste organ (barbels) of this animal are reported here. When sodium [32P]phosphate was incubated with minced pieces of epithelium from the taste organ ofI. punctatus, phospholipids became labeled. Maximal incorporation occurred near 20 min for lysophosphatidylcholines (LPC),phosphatidylcholines (PC) and phosphatidylinositols (PI). The phosphatidylethanolamines (PE) and phosphatidylserines (PS) became labeled more slowly. The label in LPC and PC declined from 20 min to 120 min, while that of the other fractions increased or was stable over the 20–120 min time period. Upon addition of 1,2‐di‐[1′‐14C]palmitoyl‐sn‐glycero‐3‐phosphocholine to the medium,14C was found within minutes in all of the phospholipids assayed. The amount of label incorporated increased with time, with maximum labeling for all phospholipids occurring at 15 min. However,14C appeared predominantly first (by 5 min) in a neutral lipid fraction (fraction AG, consisting of free fatty acids, mono‐ and diglycerides, triglycerides and methyl esters), then declined rapidly as the phospholipids gradually incorporated more label. Within minutes of addition of 1‐[1′‐14C]palmitoyl‐sn‐glycero‐3‐phosphocholine (lysophosphatidylcholine) the14C‐label was detected in the neutral lipid fraction AG, then in the PC fraction, and later in the other phospholipids. The PC fraction was maximally labeled by 40 min.Using the appropriate radiolabeled substrates, lysophosphatidylcholine phospholipase A1 and phosphatidylcholine phospholipase D activities were detected in this tissue. Very low activity of a phosphatidylcholine phospholipase A2 was observed. The experiments indicate that there are active and rapid exchange, degradation, synthesis and scavenger pathways of phospholipids in the taste organ of this animal, and suggest that phospholipases A1 and D‐type activities are primarily responsible for the rapid breakdown of LPC and PC.
Effect of dietary palm oil and its fractions on rat plasma and high density lipoprotein lipids
Authors: Sundram Kalyana , Khor Hun Teik , Ong Augustine S. H. 
Published: November 2006

AbstractMale Sprague Dawley rats were fed semipurified diets containing 20% fat for 15 weeks. The dietary fats were corn oil, soybean oil, palm oil, palm olein and palm stearin. No differences in the body and organ weights of rats fed the various diets were evident. Plasma cholesterol levels of rats fed soybean oil were significantly lower than those of rats fed corn oil, palm oil, palm olein or palm stearin. Significant differences between the plasma cholesterol content of rats fed corn oil and rats fed the three palm oils were not evident. HDL cholesterol was raised in rats fed the three palm oil diets compared to the rats fed either corn oil or soybean oil. The cholesterol‐phospholipid molar ratio of rat platelets was not influenced by the dietary fat type. The formation of 6‐keto‐PGF1α was significantly enhanced in palm oil‐fed rats compared to all other dietary treatments. Fatty acid compositional changes in the plasma cholesterol esters and plasma triglycerides were diet regulated with significant differences between rats fed the polyunsaturated corn and soybean oil compared to the three palm oils.
Separation and differential activation of rat liver cytosolic cholesteryl ester hydrolase, triglyceride lipase and retinyl palmitate hydrolase by cholestyramine and protein kinases
Authors: Ghosh Shobha , Kounnas Maria Z. , Grogan W. McLean 
Published: November 2006

AbstractCholesteryl ester hydrolase (CEH), triacylglycerol lipase (TGL) and retinyl palmitate hydrolase (RPH) were measured in 104,000 ×g supernatants from rat liver under optimal conditions for measurement of cytosolic CEH. Similar levels of hydrolytic activity were seen with oil droplet dispersions of cholesteryl oleate, trioleoylglycerol and retinyl palmitate. No cytosolic TGL activity was seen with substrate presented in the triton‐albumin emulsion used for measurement of lipoprotein lipase‐like TGL associated with hepatic plasma membrane. Cytosolic CEH, TGL and RPH were differentially partially purified by both ammonium sulfate precipitation and anion exchange fast protein liquid chromatography (FPLC). Of the three activities, only CEH was stimulated by cholestyramine feeding and by activators of protein kinases A and C. All three activities were inhibited by alkaline phosphatase treatment, although to different degrees. It is concluded that these activities are catalyzed by at least three differentially regulated enzymes with a high degree of specificity for their respective substrates.
Identification of the new 18‐hexacosenoic acid in the spongeThalysias juniperina
Authors: Carballeira Nestor M. , Shalabi Fathi , Maldonado Maria E. 
Published: November 2006

AbstractThe phospholipid fatty acids from the spongeSpheciospongia cuspidifera were studied revealing the presence of the rare 10‐octadecenoic acid (10−18∶1) and a new 2‐methoxyhexadecenoic acid. The phospholipid fatty acids fromThalysias juniperina were also studied revealing the presence of the hitherto unreported 18‐hexacosenoic acid (18−26∶1). These results tend to indicate that the biosynthetic pathway from 10−18∶1 to 18−26∶1 may be operative in nature. The phospholipid mixture from the sponges was also analyzed by31P‐NMR and shown to mainly consist of phosphatidylethanolamine, phosphatidylserine, phosphatidylinositol, and phosphatidylglycerol. Phosphatidylcholine was not found in the sponges analyzed in this work.
(3H/14C)Beta‐methylheptadecanoic acid subcellular distribution and lipid incorporation in mouse heart
Authors: Livni Eli , Ito Susumu , Kassis Amin I. , Elmaleh David R. 
Published: November 2006

AbstractBeta‐methylfatty acids are transported into myocardial cells as other fatty acids would be, but are incapable, for example, of undergoing complete catabolism. Our previous studies have established the structure‐location relationship and the imaging characteristics of these analogs. In the present study in mouse myocardium, microautoradiography and electron microscopy were used to show the distribution of [7,8‐3H] beta‐methylheptadecanoic acid ([3H]BMHA) in mitochondria and lipid droplets. Thin‐layer chromatography demonstrated the presence of [1‐14C] beta‐methylheptadecanoic acid ([14C]BMHA) and its metabolites in various lipid pools. These studies complement our earlier findings which showed that similarities exist in the initial metabolic fate of BMHA and physiological fatty acids.
Effect of phosphatidylcholine on the α‐lactalbumin‐induced fusion of vesicles
Authors: Park Byoung Sun , Kim Jeongha , Kim Uh Hee , Kim Hyoungman 
Published: November 2006

AbstractPrevious studies on α‐lactalbumin induced fusion of phosphatidylserine/phosphatidylethanolamine vesicles are extended to vesicles composed of various combinations of phosphatidylserine, phosphatidylethanolamine, phosphatidylcholine and cardiolipin. It was found that inclusion of phosphatidylcholine in the vesicles results in a depression of fusion. This depression of fusion appears to be caused by a reduction in the amount of irreversibly bound α‐lactalbumin to vesicles containing phosphatidylcholine. It is suggested that in this system fusion is dependent upon the extent by which a particular protein segment penetrates the bilayer.
Hepatic biotransformation and choleretic effect of 7‐ketolithocholic acid in the rat
Authors: Kanai Setsuko , Sato Yuko , Nokubo Munetaka , Kitani Kenichi 
Published: November 2006

AbstractHepatic biotransformation and the effect on bile flow of 7‐ketolithocholic acid (7‐oxo‐3α‐hydroxy‐5β‐cholan‐24‐oic acid), in comparison to ursodeoxycholic acid, were examined in rats under conditions of continuous infusion of solutions of sodium salts of these bile acids (1.2μmol/min/100 g body wt) for 2 hr. Both bile salts elevated the bile flow rate as well as the bile bicarbonate concentration to a similar degree. The minor difference observed was a transient (10–20 min) and subtle drop of bile flow during the first hour in rats given 7‐ketolithocholate. In ursodeoxycholate infused rats, the major bile salt in the bile was its taurine conjugate, although excretion of tauroursodeoxycholate dropped considerably during the second hour. In 7‐ketolithocholate infused rats, the major bile salt in the bile was again, its taurine conjugate, but ursodeoxycholate and chenodeoxycholate and their conjugates were also excreted. In contrast to ursodeoxycholate infused rats, the drop in excretion of taurine conjugates and the increase of glycine conjugates in rats infused with 7‐ketolithocholate were more rapid. In rats infused with 7‐ketolithocholate, excretion of ursodeoxycholate and its conjugates was significantly higher than the corresponding values for chenodeoxycholate, suggesting that 7‐ketolithocholate is reduced predominatly to the 7β‐epimer in this species. However, the concentration of ursodeoxycholate and its conjugates excreted into the bile in rats infused with 7‐ketolithocholate was only 10% of that of rats infused with ursodeoxycholate, yet the magnitude of choleresis and the rise in bile bicarbonate concentration were similar in both experiments. Therefore, it is suggested that the bicarbonate‐rich bile, induced by 7‐ketolithocholate infusion, is caused mainly by 7‐ketolithocholate rather than by its metabolite, ursodeoxycholate.
Thiobarbituric acid‐reactive substances from peroxidized lipids
Authors: Kosugi Hiroko , Kojima Takashi , Kikugawa Kiyomi 
Published: November 2006

AbstractThe thiobarbituric acid (TBA) reaction was performed on linoleic acid 13‐monohydroperoxide, autoxidized fatty esters, edible fats and oils, rat liver microsomal lipids, and on human erythrocyte ghost lipids in order to determine which substances from peroxidized lipids are TBA‐reactive. The reaction was carried out in 2% acetic acid containing butylated hydroxytoluene using two different reaction modes: a one‐step mode which involves heating at 100°C, and a two‐step mode which involves first treatment at 5°C and subsequent heating at 100°C. Yields of the red 1∶2 malonaldehyde/TBA adduct, as estimated by absorbance, fluorescence intensity and high‐performance liquid chromatography, were much higher than the malonaldehyde content as determined by direct chemical analysis. Yields of red pigment obtained by the two‐step mode were slightly higher than those obtained by the one‐step mode. Pigment yields were dramatically increased by addition oft‐butyl hydroperoxide. Red pigment formation from alkenals and alkadienals was similarly enhanced by the two‐step mode or by addition oft‐butyl hydroperoxide, whereas pigment formation from malonaldehyde was not. It appears likely that a component of the total red pigment formed from the peroxidized lipids was due to aldehyde species other than malonaldehyde.
Gas chromatographic analysis of free and bound malonaldehyde in rat liver homogenates
Authors: Ichinose T. , Miller M. G. , Shibamoto Takayuki 
Published: November 2006

AbstractA gas chromatographic method for the measurement of free and bound malonaldehyde (MA) in rat liver homogenate was developed to investigate biological damage caused by lipid peroxidation. Free MA was derivatized by reaction withN‐methylhydrazine (NMH) to form 1‐methylpyrazole (1‐MP), which was subsequently analyzed by capillary gas chromatography (GC). Bound forms of MA were determined by first hydrolyzing samples in acetic acid, then measuring the free MA as 1‐MP. Bound MA in rat liver was released within 15 min by acid hydrolysis. A slight increase in bound MA levels in rat liver was observed 1 hr after CCl4 treatment, with bound MA then returning to control levels. Free MA levels and thiobarbituric acid assay (TBA) values did not show appreciable changes over a 24‐hr period after CCl4 administration. However, the TBA values were approximately ten times the MA values in most samples.
The occurrence of estrone and estriol intrichostrongylus colubriformis (nematoda)
Authors: Lee Hui‐Minn , Parish Edward J. , Bone Leon W. 
Published: November 2006

AbstractMammalian sex steroids and cholesterol wre isolated from the lipid extract of the zooparasitic nematodeTrichostrongylus colubriformis. In addition to the previously identified sex steroids progesterone and testosterone, estrone and estriol were detected and isolated from the mixture. The steroids were analyzed by thin‐layer gas‐liquid and high‐performance liquid chromatography, and their structures confirmed by proton nuclear magnetic resonance and mass spectroscopy.
Time dependent changes occurring in rat liver microsomes upon lipid peroxidation
Authors: Ifoh Fumiaki , Minamide Yoshiyuki , Horie Toshiharu , Awazu Shoji 
Published: November 2006

AbstractSteady‐state fluorescence anisotropy of diphenylhexatriene and n‐(9‐anthroyloxy)stearic acids (n=2,12) in rat liver microsomes showed a marked increase in the early stages of enzymatically or non‐enzymatically induced lipid peroxidation. The changes in fluorescence anisotropy occurred in parallel with the formation of thiobarbituric acid‐reactive substances (TBA‐RS). Parallel to these changes, the fluorescence emitted from peroxidized microsomes increased markedly in the early stages of lipid peroxidation. In contrast to the changes in the fluorescence anisotropy and in the formation of TBA‐RS, the fluorescence showed a continuing increase over the three hr period of lipid peroxidation. Glucose‐6‐phosphatase was inactivated in the early stages of lipid peroxidation, whereas NADH‐cytochrome b5 reductase underwent a slow deactivation over three hr. The apparently slow deactivation of the peripheral protein may be explained by the formation of fluorescent substances.
Overexpression of aRhizopus delemar lipase gene inEscherichia coli
Authors: Joerger Rolf D. , Haas Michael J. 
Published: November 2006

AbstractA cloned complementary deoxyribonucleic acid encoding the precursor polypeptide of an extracellular lipase from the fungusRhizopus delemar was altered by site‐directed mutagenesis to generate deoxyribonucleic acid fragments that specifically code for the polypeptides of the proenzyme and the mature form of the lipase. Attempts to produce these polypeptides in enzymatically active form inEscherichia coli revealed toxic effects toward the host. Therefore the polypeptides were expressed as inactive and insoluble forms in the cytoplasm ofE. coli BL21 (DE3) cells using plasmid vector pET11‐d. With this tightly regulated high‐level expression system, lipase and prolipase polypeptides were produced to estimated levels of up to 21% and 15%, respectively, of total cellular protein. The insoluble polypeptides were solubilized in 8 M urea. Refolding into active forms was achieved by treatment with the redox system cystine/cysteine and dilution. Refolded mature lipase was purified to homogeneity by affinity and ion exchange chromatography. The enzyme had a specific activity comparable to that of lipase from the fungal culture. The quantities of pure enzyme obtained from a 1‐L culture ofE. coli exceeded those obtained from the fungal culture by a factor of at least 100. Refolded recombinant prolipase was purified essentially to homogeneity and had a specific activity similar to that of the mature enzyme. Its pH optimum was 7.5, rather than the pH 8 determined for recombinant mature lipase and for the enzyme purified from the fungal culture. Recombinant prolipase retained activity after 15 min incubation at 65°C, while mature lipase retained activity only up to 45°C.