bluuebunny/crossref_metadata_2025_split huggingface dataset:
Characterization of phospholipase D activity in bovine photoreceptor membranes
Authors: Salvador G. A. , Giusto N. M. 
Published: November 2006

AbstractPhospholipase D (E.C. 3.1.4.4.) was detected in isolated bovine rod outer segments (ROS) and its properties determined. The enzyme activity was assayed using either a sonicated microdispersion of 1,2‐diacyl‐sn‐[23H]glycerol‐3‐phosphocholine (PC), or [14C]ethanol. Using [3H]PC and ethanol as a substrate, we were able to detect the hydrolytic properties as well as the transphosphatidylation reaction catalyzed by phospholipase D (PLD): formation of [3H]phosphatidic acid and phosphatidylethanol [3H]PtdEt; whereas with [14C]ethanol or [3H]glycerol in the absence of exogenous PC, only transphosphatidylation reactions were detected (formation of [14C]PtdEt or [3H]phosphatidylglycerol, respectively). The use of varying concentrations of [3H]PC and 400 mM of ethanol gave an apparent Km value for PC of 0.51 mM and a Vmax value of 111 nmol × h−1 × (mg protein)−1. The activity was linear up to 60 min of incubation and up to 0.2 mg of protein. The optimal ethanol concentration was determined to be 400 mM, with an apparent Km of 202 mM and a Vmax value for ethanol of 125 nmol × h−1 × (mg protein)−1. A clear pH optimum was observed around 7. PLD activity was increased in the presence of 3‐[(3‐cholamidopropyl)dimethylammonio]‐1‐propane‐sulfonate or sodium deoxycholate and inhibited with Triton X‐100. The enzyme activity was also activated in the presence of Ca2+ or Mg2+ (1 mM) although these ions were not required for measuring PLD activity. The high specific activity of PLD found in purified ROS compared to the activity found in other subcellular fractions of the bovine retina suggests that this enzymatic activity is native to ROS. The present report is the first evidence of PLD activity associated with photoreceptor ROS.
Lipase specificity toward some acetylenic and olefinic alcohols in the esterification of pentanoic and stearic acids
Authors: Lie Ken Jie Marcel S. F. , Fu Xun 
Published: November 2006

AbstractThe esterification of five medium‐ and long‐chain acetylenic alcohols (2‐nonyn‐1‐ol, 10‐undecyn‐1‐ol, 6‐octadecyn‐1‐ol, 9‐octadecyn‐1‐ol, and 13‐docosyn‐1‐ol), seven olefinic alcohols (cis‐3‐nonen‐1‐ol, 10‐undecen‐1‐ol, cis‐6‐octadecen‐1‐ol, cis‐9‐octadecen‐1‐ol, trans‐9‐octadecen‐1‐ol, trans‐9, trans‐11‐octadecadien‐1‐ol, cis‐9, cis‐12‐octadecadien‐1‐ol), and four short‐chain unsaturated alcohols (allyl alcohol, 3‐butyn‐1‐ol, 3‐pentyn‐1‐ol, and cis‐2‐penten‐1‐ol) with pentanoic or stearic acid in the presence of various lipase preparations was studied. With the exception of 2‐nonyn‐1‐ol, where Lipase AY‐30 (Candida rugosa) was used as the biocatalyst, the esterification of C11, C18, and C22 acetylenic alcohols with pentanoic acid appeared to be generally unaffected by the presence of an acetylenic bond in the alcohol as relatively high yields of the corresponding esters (78–97%) were obtained. However, medium‐ and long‐chain olefinic alcohols were discriminated by Lipase AY‐30, Lipolase 100T (Rhizomucor miehei), and especially by porcine pancreatic lipase (PPL), when esterification was conducted with pentanoic acid. Esterification of medium‐and long‐chain acetylenic or olefinic alcohols with a long‐chain fatty acid, stearic acid, was very efficient except when Lipase AY‐30 and Lipolase 100T were used. Short‐chain unsaturated alcohols were much more readily discriminated. 3‐Pentyn‐1‐ol and 3‐butyn‐1‐ol were difficult (<5% yield) to esterify with pentanoic or stearic acid in the presence of Lipase AY‐30 and PPL, respectively. Very low yields (<26%) of esters were produced when 3‐butyn‐1‐ol and 3‐pentyn‐1‐ol were reacted with pentanoic or stearic acid, when catalyzed by lipase from Candida cylindracea, No reaction took place between 3‐butyn‐1‐ol and stearic acid in the presence of Lipase AY‐30. Esterification of short‐chain acetylenic and olefinic alcohols was most efficiently achieved with Lipolase 100T (Rhizomucor miehei), Lipozyme IM20 (Rh. miehei), or Novozyme 435 (Candida antarctica) as the biocatalyst.
The triggering signal dictates the effect of docosahexaenoic acid on lymphocyte function in vitro
Authors: Jenski Laura J. , Scherer John M. , Caldwell LaDawn D. , Ney Victori A. , Stillwell William 
Published: November 2006

AbstractDocosahexaenoic acid (DHA) is an n‐3 fatty acid beneficial to several human conditions including inflammation and autoimmune disease. To better understand the effect of DHA on immunity, we monitored the rise in cytosolic free calcium, interleukin 2 receptor (IL2R) expression, and proliferation of splenic lymphocytes triggered with three different stimuli in the presence or absence of DHA. We found that 10 μg DHA/mL suppressed concanavalin A‐induced mitogenesis and the mixed lymphocyte reaction while concurrently enhancing proliferation stimulated with anti‐Thy‐1 antibodies. Proliferation, as measured by [3H]thymidine incorporation after 2 to 5 d of culture, was affected by DHA, but earlier activation effects such as elevation of cytosolic free calcium and IL2R expression were not altered. These results imply that DHA incorporated into membrane phospholipids differentially affects the activity of distinct membrane‐bound receptors and signaling molecules. This result suggests that DHA may be used to modulate immune responses selectively, e.g., to suppress, undesired autoimmunity while maintaining protective immunity.
Different degrees of moderate iron deficiency modulate lipid metabolism of rats
Authors: Stangl Gabriele I. , Kirchgessner Manfred 
Published: November 2006

AbstractSevere iron deficiency affects lipid metabolism. To investigate whether moderate iron depletion also alters lipid variables—including lipid levels in serum and liver, hepatic lipogenesis, and fatty acid composition indicative of an impaired desaturation—we carried out experiments with rats fed 9, 13, and 18 mg iron/kg diet over a total of 5 wk. The study also included three pair‐fed control groups and an ad libitum control group, fed with 50 mg iron/kg diet. The iron‐depleted rats were classified as iron‐deficient on the basis of reduced serum iron, hemoglobin concentration, and hematocrit. All moderately iron‐deficient rats had significantly lower cholesterol concentrations in liver and serum lipoproteins than their pair‐fed controls. Rats with the lowest dietary iron supply had higher concentrations of hepatic phosphatidylcholine (PC) and phosphatidylethanolamine (PE), lower activities of glucose‐6‐phosphate dehydrogenase, malic enzyme and fatty acid synthase, and higher triacylglycerol concentrations in serum lipoproteins than the corresponding pair‐fed control rats. Moderate iron deficiency also depressed the serum phospholipid level. Moreover, several consistent significant differences in fatty acid composition of hepatic PC and PE occurred within moderate iron deficiency, which indicate impaired desaturation by Δ‐9 and Δ‐6 desaturases of saturated and essential fatty acids. We conclude that lipid variables, including cholesterol in liver and serum lipoproteins as well as fatty acid desaturation, reflect the gradations of iron status best and can be used as an indicator of the degree of moderate iron deficiency.
Effects of dietary methionine and cystine on lipid metabolism in hepatoma‐bearing rats with hyperlipidemia
Authors: Kawasaki Masashi , Funabiki Ryuhei , Yagasaki Kazumi 
Published: November 2006

AbstractAbnormal lipid metabolism and its restoration by dietary methionine (Met) and cystine (Cys) were studied in Donryu rats subcutaneously implanted with an ascites hepatoma cell line of AH109A. The hepatoma‐bearing rats exhibited byperlipidemia characterized by rises in serum triglyceride and cholesterol levels. Decreased lipoprotein lipase (LPL) activities in epididymal adipose tissue, cardiac muscle, and gastrocnemius as well as increased fatty acid mobilization from adipose tissue were considered to be responsible for the hepatoma‐induced hypertriglyceridemia, while increased hepatic cholesterogenesis and decreased steroid excretion into feces were thought to be responsible for the hepatoma‐induced hypercholesterolemia. Dietary‐supplemented Met or Cys reduced the AH109A‐induced hypertriglyceridemia with suppression of fatty acid synthesis in the host liver. Met restored the fall of LPL activities, while Cys did not. Dietary Met or Cys also reduced the hypercholesterolemia with restoration of decreased bile acid excretion into feces. These results suggest that dietary Met or Cys is hypolipidemic in the hepatoma‐bearing rats with slight differences in their modes of action.
An efficient ultrasound‐assisted zinc reduction of fatty esters containing conjugated enynol and conjugated enynone systems
Authors: Lie Ken Jie Marcel S. F. , Mustafa Jamal , Pasha Mohammed Khysar 
Published: November 2006

AbstractReduction of methyl 8‐hydroxy‐11‐E/Z‐octadecen‐9‐ynoate (1) with zinc in either aqueous n‐propanol or water under concomitant ultrasound irradiation furnished a mixture of methyl 8‐hydroxy‐9Z,11E‐octadecadienoate (3a) and methyl 8‐hydroxy‐9Z, 11Z‐octadecadienoate (3b) (96% yield). Reduction of methyl 8‐oxo‐11‐E/Z‐octadecen‐9‐ynoate (2) under similar conditions gave methyl 8‐oxo‐10‐Z‐octadecenoate exclusively (4, 70%). The latter compound was epoxidized and converted to a C18 furanoid fatty ester (6, methyl 8,11‐epoxy‐8,10‐octadecadienoate) in 70% yield.
Assessment of the arachidonic acid content in foods commonly consumed in the American diet
Authors: Taber Laura , Chiu Chun‐Hung , Whelan Jay 
Published: November 2006

AbstractArachidonic acid (AA) is an extremely important fatty acid involved in cell regulation. When provided in the diet, it is cogently incorporated in membrane phospholipids and enhances eicosanoid biosynthesis in vivo and in vitro; however, controversy exists as to the levels of AA in food and in the diet. This study determined the amount of AA in cooked and raw portions of beef (rib eye), chicken (breast and thigh), eggs, pork (loin), turkey (breast), and tuna; it compared these results to values published in Agriculture Handbook No. 8 (HB‐8). The cooked portions were prepared as described in HB‐8. With the exception of chicken thigh and tuna, the levels of AA (w/w) in the selected foods analyzed were significantly higher, in general, than those values published in HB‐8. The greatest differences were observed in beef (raw and cooked), turkey breast (raw and cooked), and pork (cooked) where AA levels were twice that of the values in HB‐8. In contrast, the AA and n‐3 fatty acid contents in tuna were almost half the HB‐8 values. The present data indicate that HB‐8 tends to underreport the amounts of AA in a number of foods commonly consumed in the American diet, and new initiatives should be considered to validate and update the current database for fatty acid composition of foods.
Fish oil supplementation with and without added vitamin E differentially modulates plasma antioxidant concentrations in healthy women
Authors: Turley E. , Wallace J. M. W. , Gilmore W. S. , Strain J. J. 
Published: November 2006

AbstractThe purpose of this study was to assess the effect of fish oil with or without vitamin E on plasma vitamin antioxidants. Thirty‐three apparently healthy women aged 18–28 yr were recruited from the university environs, and 30 completed the double‐blinded, parallel design supplementation trial. Blood samples were collected at baseline (week 0) and following 28 d of supplementation with three capsules/d (0.8 g×3) of either fish oil (FO) or FO with vitamin E (3 IU/g) (FOE). An additional blood sample was taken at day 91 (washout). Plasma antioxidant vitamins, fatty acid composition, and lipid peroxides were measured. Plasma α‐tocopherol concentrations were increased significantly in both groups postsupplementation FO (P=0.018) and FOF (P=0.003) compared with baseline and washout values. Plasma retinol concentration was significantly increased (P=0.034) compared with baseline and washout values following supplementation with FOE but not FO, while plasma β‐carotene was significantly increased (P=0.036), compared with baseline and washout values, following supplementation with FO but not FOE. There was a trend (P=0.059) toward decreased plasma ascorbic acid following FO supplementation compared with baseline and washout. Plasma lipid peroxides did not change following either supplementation. Results suggest that low‐dose FO feeding with and without vitamin E differentially modulates plasma antioxidant vitamins but has no significant effect on lipid peroxidation.
Effect of dietary cholesterol on low density lipoprotein‐receptor, 3‐hydroxy‐3‐methylglutaryl‐CoA reductase, and low density lipoprotein receptor‐related protein mRNA expression in healthy humans
Authors: Boucher Philippe , de Lorgeril Michel , Salen Patricia , Crozier Pierre , Delaye Jacques , Vallon Jean‐Jacques , Geyssant André , Dante Robert 
Published: November 2006

AbstractWe investigated the possibility that dietary cholesterol downregulates the expression of low density lipoprotein (LDL) receptor and 3‐hydroxy‐3‐methylglutaryl (HMG)‐CoA reductase genes of circulating mononuclear cells in vivo in healthy humans. We also studied the variations of the LDL receptor‐related protein (LRP) gene in the same conditions. Dieters (n=5) were submitted to a 4‐d fat restriction (mean cholesterol intake: 6±4 mg/d), followed by a 7‐d cholesterol (a mean of 791±150 mg/d) supplementation. Controls (n=3) did not change their diet. During fat restriction, serum total and LDL cholesterol decreased significantly (P<0.05), and LDL receptor and HMG‐CoA reductase mRNA copy numbers in mononuclear cells increased by 57 and 147%, respectively (P<0.05). After reintroducing cholesterol, serum cholesterol was stable whereas LDL receptor and HMG‐CoA reductase mRNA decreased by 46 and 72% (P<0.05) and LRP mRNA increased by 59% (P<0.005). The changes in LDL receptor and HMG‐CoA reductase mRNA abundance were correlated (r=+0.79, P=0.02) during cholesterol reintroduction as were LDL receptor and LRP mRNA levels, but negatively (r=−0.70, P=0.05). Also, 70% of the variability in LRP mRNA (P<0.005) was explained by dietary cholesterol. Thus, the basic mechanisms regulating cellular cholesterol content, the coordinate feedback repression of genes governing the synthesis and uptake of cholesterol, are operating in vivo in humans. However, serum cholesterol did not increase in response to dietary cholesterol, suggesting that these mechanisms may not play as predominant a role as previously believed in the short‐term control of serum cholesterol in vivo in humans. A new finding is that LRP gene is also sensitive to dietary cholesterol, suggesting that it may participate in the control of serum cholesterol. Further in vivo studies in humans are warranted to explore the molecular mechanisms of the physiological response to dietary cholesterol in humans.
Effect of diet on the fatty acid and molecular species composition of dog retina phospholipids
Authors: Delton‐Vandenbroucke Isabelle , Maude Maureen B. , Chen Huiming , Aguirre Gustavo D. , Acland Gregory M. , Anderson Robert E. 
Published: November 2006

AbstractDogs were born to mothers fed commercial diets low or enriched in n‐3 fatty acids and raised on those diets until they were about 50 d old. Retinas were removed, lipids were extracted, and total phospholipids were anlyzed for fatty acid and molecular species composition. Animals from the low n‐3 group had significantly lower retinal levels of 22∶6n‐3 and higher levels of n‐6 fatty acids, especially 20∶4n‐6 and 22∶5n‐6. There was no difference in the retinal levels of 18∶2n‐6, and only small differences were found in saturated and monounsaturated fatty acids. The most dramatic differences in molecular species occurred in 22∶6n‐3‐22∶6n‐3 (4.7 vs. 0.8%) and 18∶0‐22∶6n‐3 (27.6 vs. 14.4%); total molecular species containing 22∶6n‐3 were significantly lower in the low n‐3 group (45.5 vs. 24.0%). Molecular species containing 20∶4n‐6 and 22∶5n‐6 were greater in the low n‐3 animals (13.0 vs. 25.7%), as were molecular species containing only saturated and monounsaturated fatty acids (40.8 vs. 35.4%). These results show that modest differences in the amount of n‐3 fatty acids in the diets of dogs can have profound effects on the fatty acid and molecular species composition of their retinas.
Phytanic acid α‐hydroxylation by bacterial cytochrome P450
Authors: Matsunaga Isamu , Sumimoto Tatsuo , Kusunose Emi , Ichihara Kosuke 
Published: November 2006

AbstractFatty acid α‐hydroxylase, a cytochrome P450 enzyme, from Sphingomonas paucimobilis, utilizes various straight‐chain fatty acids as substrates. We investigated whether a recombinant fatty acid α‐hydroxylase is able to metabolize phytanic acid, a methyl‐branched fatty acid. When phytanic acid was incubated with the recombinant enzyme in the presence of H2O2, a reaction product was detected by gas chromatography, whereas a reaction product was not detected in the absence of H2O2. When a heat‐inactivated enzyme was used, a reaction product was not detected with any concentration of H2O2. Analysis of the methylated product by gas chromatography‐mass spectrometry revealed a fragmentation pattern of 2‐hydroxyphytanic acid methyl ester. By single‐ion monitoring, the mass ion and the characteristic fragmentation ions of 2‐hydroxyphytanic acid methyl ester were detected at the retention time corresponding to the time of the product observed on the gas chromatogram. The Km value for phytanic acid was approximately 50 μM, which was similar to that for myristic acid, although the calculated Vmax for phytanic acid was about 15‐fold lower than that for myristic acid. These results indicate that a bacterial cytochrome P450 is able to oxidize phytanic acid to form 2‐hydroxyphytanic acid.
Inhibition of lipoxygenase 1 by phosphatidylcholine micelles‐bound curcumin
Authors: Began G. , Sudharshan E. , Rao A. G. Appu 
Published: November 2006

AbstractCurcumin (diferuloyl methane) from rhizomes of Curcuma longa L. binds to phosphatidylcholine (PC) micelles. The binding of curcumin with PC micelles was followed by fluorescence measurements. Curcumin emits at 490 nm with an excitation wavelength of 451 nm after binding to PC‐mixed micelles stabilized with deoxycholate. Curcumin in aqueous solution does not inhibit dioxygenation of fatty acids by Lipoxygenase 1 (LOX1). But, when bound to PC micelles, it inhibits the oxidation of fatty acids. The present study has shown that 8.6 μM of curcumin bound to the PC micelles is required for 50% inhibition of linoleic acid peroxidation. Lineweaver‐Burk plot analysis has indicated that curcumin is a competitive inhibitor of LOX1 with Kl of 1.7 μM for linoleic and 4.3 μM for arachidonic acids, respectively. Based on spectroscopic measurements, we conclude that the inhibition of LOX1 activity by curcumin can be due to binding to active center iron and curcumin after binding to the PC micelles acts as an inhibitor of LOX1.
Chemiluminescent determination of cholesterol hydroperoxides in human erythrocyte membrane
Authors: Adachi Junko , Asano Migiwa , Naito Takeaki , Ueno Yasuhiro , Tatsuno Yoshitsugu 
Published: November 2006

AbstractA method for separating, detecting, and quantifying cholesterol hydroperoxide (Ch‐OOH) based on extraction, purification by solid‐phase extraction cartridge, high‐performance liquid chromatography with chemiluminescent detection (HPIC‐CI), and liquid chromatography mass spectrometry has been developed for human erythrocyte membrane. We prepared standard compounds of the cholesterol 5α‐, 7α‐, and 7β‐hydroperoxides (Ch 5α‐OOH, Ch 7α‐OOH, and Ch 7β‐OOH). An octyl silica column with methanol/water/acetonitrile 89∶9∶2 (by vol) as eluent was used to determine Ch‐OOH. HPLC‐CL that incorporated cytochrome c and luminol as the post‐column luminescent reagent was used. We also investigated the optimal assay conditions and how to prevent formation of artifact Ch‐OOH. Analysis of erythrocyte membranes from seven healthy volunteers identified Ch 7α‐OOH and Ch 7β‐OOH, but not Ch 5α‐OOH, as commonly occurring components. The respective mean concentrations of Ch 7α‐OOH and Ch 7β‐OOH were 2,5±1.6 and 5A±3.5 pmol/mL blood.
Lymphatic fatty acid absorption profile during 24 hours after administration of triglycerides to rats
Authors: Porsgaard Trine , Straarup Ellen Marie , Høy Carl‐Erik 
Published: November 2006

AbstractIn this study we determined in rats the complete 24‐h lymphatic fatty acid profile after administration of either rapeseed oil (RO) or rapeseed oil interesterified with 10∶0 (RO/C10) with special emphasis on the transition from absorptive to postabsorptive phase. Rats were subjected to cannulation of the main mesenteric lymph duct and the next day oils were administered through a gastric feeding tube. Lymph was collected in 1‐h fractions for the following 24 h. The time for maximum lymphatic transport of fatty acids was at 4 h with fast changes in fatty acid composition from the fatty acids of endogenous origin to those of the administered oils. Seven to eight hours after administration the transport was significantly lower than maximum, indicating the change from absorptive to postabsorptive phase. At 24 h after administration of either oil the transport of total fatty acids, palmitic acid (16∶0), and linoleic acid (18∶2n−6) together with oleic acid (18∶1n−9) after RO had not returned to the transport at baseline. In contrast, the transport of decanoic acid (10∶0) and α‐linolenic acid (18∶3n−3) returned to baseline values between 12 and 15 h. This indicated that the absorption of purely exogenous fatty acids (illustrated by 10∶0 and 18∶3n−3) was complete at 15 h and that the fatty acids transported between 15 and 24 h were derived mostly from endogenous stores.