bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of growth temperature on the positional distribution of eicosapentaenoic acid andrans hexadecenoic acid in the phospholipids of aVibrio species of bacterium
Authors: Henderson R. J. , Millar R. M. , Sargent J. R. 
Published: November 2006

AbstractPhosphatidylethanolamine (PE) and phosphatidylglycerol (PG) were isolated from aVibrio species of bacterium, known to produce eicosapentaenoic acid (20∶5n−3) andtrans‐hexadecenoic acid (16∶1n−7), and subjected to phospholipase A2 degradation to determine the positional distribution of component fatty acids. At the two growth temperatures studied (20 and 5°C), both 20∶5n−3 andtrans 16∶1 n−7 were located mainly at positionsn−2 in PE. Increases in the proportions of 20∶5n−3 andtrans 16∶1n−7 in positionsn−2 with decreasing growth temperature were balanced mainly by decreases in the level ofiso‐15∶0. In PG,trans 16∶1n−7 was located predominantly in positionsn‐1, although the difference between the two positions was not as great as in PE. Eicosapentaenoic acid was preferentially located in positionsn‐2 of PG, particularly at 5°C when it comprised 29.9% of the total fatty acids in this position. It is concluded thattrans 16∶1n−7/20∶5n−3 is not a major molecular species of phospholipid in this species ofVibrio and that changes in the levels of molecular species of PE containingiso‐15∶0 may feature in thermal acclimation.
β‐Carotene transport in human lipoproteins. Comparisons with a‐tocopherol
Authors: Traber Maret G. , Diamond Seth R. , Lane Jerome C. , Brody Rachel I. , Kayden Herbert J. 
Published: November 2006

AbstractThe purpose of this study was to investigate the temporal relationships of the transport of β‐carotene in human lipoproteins. We administered 60 mg β‐carotene with breakfast to nine fasting subjects, then blood samples were collected at intervals of up to 75 h, lipoproteins were isolated, and β‐carotene was quantitated. β‐Carotene concentrations in chylomicrons and very low density lipoproteins (VLDL) peaked at 6 and 9 h, respectively. Nonetheless, at all time points the majority of plasma β‐carotene was contained in low density lipoproteins (LDL), while high density lipoproteins (HDL) carried a smaller portion (at 24 h, 73±8% in LDL as compared with 23±5% in HDL). In three subjects, transport of β‐carotene was compred with the results of earlier studies on the transport of stereoisomers of α‐tocopherol. Unlike plasmaRRR‐α‐tocopherol concentrations, which are maintained by the preferential incorporation ofRRR‐α‐tocopherol into VLDL by the liver, β‐carotene increased and decreased in VLDL similarly toSRR‐α‐tocopherol, a stereoisomer whose concentrations are not maintained in plasma. In conclusion, β‐carotene is primarily transported in the plasma in LDL, but its incorporation by the liver into lipoproteins does not appear to be enhanced.
Upregulation of low density lipoprotein receptor activity by tumor necrosis factor, a process independent of tumor necrosis factor‐induced lipid synthesis and secretion
Authors: Liao Wei , Florén Claes‐Henrik 
Published: November 2006

AbstractIt has been shown that tumor necrosis factor (TNF) rapidly upregulates expression of the low density lipoprotein (LDL) receptors on Hep G2 cells and acutely stimulates hepatic lipid synthesis and secretionin vivo. It may thus be possible that TNF‐induced expression of LDL receptors is secondary to a decrease in cellular cholesterol content caused by TNF‐stimulated lipid secretion. In order to know whether TNF upregulates LDL receptors by depletion of the cellular cholesterol content, the present experiments were designed to study the temporal relationship between TNF‐stimulated expression of LDL receptor activity and TNF‐induced changes in lipid synthesis and secretion in anin vitro setting by using Hep G2 cells (a highly differentiated human hepatoma cell line) as a hepatocyte model. Hep G2 cells were incubated with TNF (usually 2.5 nmol/L) for certain periods, and LDL receptor activity was evaluated by measuring [125I]LDL binding at 4°C; lipid synthesis and secretion were assayed by measuring [3H]glycerol incorporation into triglycerides and phospholipids as well as [14C]acetate incorporation into cholesterol. We found that a 30‐h exposure of the cells to TNF was needed for the effect of TNF to be seen on lipid synthesis and secretion as measured by incorporation of [3H]glycerol into triglycerides and phospholipids, whereas TNF rapidly (in several hours) upregulated LDL receptor activity. TNF stimulated triglyceride synthesis, but did not stimulate phospholipid synthesis. On the other hand, TNF stimulated phospholipid secretion, but did not stimulate triglyceride secretion. Exposure of the cells to TNF for 16 or 24 h neither decreased cholesterol synthesis nor stimulated cholesterol secretion as measured by [14C]acetate incorporation into cholesterol. Upregulation of LDL receptor activity through inhibition of cellular cholesterol synthesis with compactin (a competitive inhibitor of the 3‐hydroxyl‐3‐methylglutaryl‐CoA reductase) was augmented by TNF, whereas downregulation of LDL receptor activity through stimulation of cellular cholesterol synthesis with mevalonolactone almost completely blocked the upregulatory effect of TNF. In conclusion, TNF‐stimulated expression of LDL receptor activity is not secondary to a depletion of cellular cholesterol content through TNF‐stimulated lipid secretion or inhibition of cholesterol synthesis.
Linoleic acid uptake by isolated enterocytes: Influence of α‐linolenic acid on absorption
Authors: Goré Jacques , Hoinard Claude , Couet Charles 
Published: November 2006

AbstractIn a previous study we showed that intestinal uptake of α‐linolenic acid (18∶3n−3) was carrier‐mediated and we suggested that a plasma membrane fatty acid protein was involved in the transport of long‐chain fatty acids. To further test this hypothesis, the mechanism of linoleic acid (18∶2n−6) uptake by isolated intestinal cells was examined using a rapid filtration method and 20 mM sodium taurocholate as solubilizing agent. Under these experimental conditions transport of [1‐14C]linoleic acid monomers in the concentration range of 2 to 2220 nM was saturable with a Vm of 5.1±0.6 nmol/mg protein/min and a Km of 183±7 nM. Experiments carried out in the presence of metabolic inhibitors, such as 2,4‐dinitrophenol and antimycin A, suggested that an active, carriermediated mechanism was involved in the intestinal uptake of this essential fatty acid. The addition of excess unlabeled linoleic acid to the incubation medium led to a 89% decrease in the uptake of [1‐14C]linoleic acid, whiled‐glucose did not compete for transport into the cell. Other long‐chain polyunsaturated fatty acids added to the incubation mixture inhibited linoleic acid uptake by more than 80%. The presence of α‐linolenic acid (18∶3n−3) in the incubation medium caused the competitive inhibition (Ki=353 nM) of linoleic acid uptake. The data are compatible with the hypothesis that intestinal uptake of both linoleic, and α‐linolenic acid is mediated by a membrane carrier common to long‐chain fatty acids.
Occurrence of 5c,8c,11c,15t‐eicosatetraenoic acid and other unusual polyunsaturated fatty acids in rats fed partially hydrogenated calola oil
Authors: Ratnayake W. M. N. , Chen Z. Y. , Pelletier G. , Weber D. 
Published: November 2006

AbstractUncommoncis andtrans fatty acids can be desaturated and elongated to produce unusual C18 and C20 polyunsaturated fatty acids in animal tissues. In the present study we examined the formation of such metabolites derived fromcis andtrans isomers of oleic and linoleic acids of partially hydrogenated vegetable oil origin in rats. For two months, aduut male rats were fed a partially hydrogenated canola oil diet containing moderately high levels oftrans fatty acids (9.6 energy%) and an adequate level of linoleic acid (1.46 energy%). Analysis of the phospholipid (PL) fatty acids of liver, heart, serum and brain showed no new C18 polyunsaturated fatty acids, except for those uncommon 18∶2 isomers originating from the diet. However, minor levels (each <0.3% PL fatty acids) of six unusual C20 polyunsaturated fatty acids were detected in the tissues examined, except in brain PL. Identification of their structures indicated that the dietary 9c,13t−18∶2 isomer, which is the majortrans polyunsaturated fatty acid in partially hydrogenated vegetable oils, was desaturated and elongated to 5c,8c,11c,15t−20∶4, possibly by the same pathway that is operative for linoleic acid. Furthermore, dietary 12c−18∶1 was converted to 8c,14c−20∶2 and 5c,8c,14c−20∶3; dietary 9c,12t−18∶2 metabolized to 11c,14t−20∶2 and 5c,8c,11c14t−20∶4, and dietary 9t,12c to 11t,14c−20∶2. These results suggested that of all the possible isomers of oleic and linoleic acids in partially hydrogenated vegetable oils, 12c−18∶1, 9c,13t−18∶2, 9c,12t−18∶2 and 9t,12c−18∶2 are the preferred substrates for desaturation and elongation in rats. However, their conversions to C20 metabolites were not as efficient as that of oleic or linoleic acids.
Rat liver chromatin phospholipids
Authors: Albi E. , Mersel M. , Leray C. , Tomassoni M. L. , Viola‐Magni M. P. 
Published: November 2006

AbstractTo shed light on the question whether the phospholipids present in chromatin are native or are due to contamination from nuclear membranes, we labeled the phospholipids of isolated nuclei and determined the amount of phospholipids (PL) and PL fatty acid composition in nuclei and chromatin. The hepatocyte nuclei were isolated and radioiodinated by the lactoperoxidase method under saturating and nonsaturating conditions, and the radioactivity associated with chromatin extracted from these nuclei was monitored. Whereas 97% the label was recovered in the nuclear membranes, only 0.08–0.6% was found in chromatin. The PL present in chromatin were relative to the amounts present in the entire nuclei and calculated as percentage of total, phosphatidylethanolamine (10%), phosphatidylserine (22%), phosphatidylinositol (19%) phosphatidylcholine (14%), and sphingomyelin (35%). In sphingomyelin of chromatin‐associated PL an enrichment in polyunsaturated fatty acids was seen. The data indicated that the PL found in isolated chromatin do not seem to be due to contamination from the nuclear membrane.
Preparation of defined molecular species of lactosylceramide by chemical deacylation and reacylation withN‐succinimidyl fatty acid esters
Authors: Kadowaki Hiroko , Grant Marianne A. 
Published: November 2006

AbstractA procedure for the preparation of specific molecular species ofd‐erythro‐lactosylceramide involving deacylation and reacylation of lactosylceramide prepared from bovine brain gangliosides is described. Lactosylceramide wasN‐deacylated by alkaline hydrolysis and the resulting four lysolactosylceramides, which contained d18∶1, d20∶1, d18∶0 and d20∶0 long‐chain bases, were simultaneously re‐N‐acylated with theN‐succinimidyl ester of either 16∶0, 18∶0, 20∶0, 24∶0, 20∶1, 22∶1 or 24∶1 fatty acid. The resulting lactosylceramide contained four molecular species of lactosylceramides, i.e., d18∶1, d20∶1, d18∶0 and d20∶0 long‐chain bases coupled with the fatty acid that was introduced. Lactosylceramides prepared in this manner were separated into four individual molecular species by high‐performance liquid chromatography (HPLC). Each of the purified molecular species of lactosylceramide was quantitated by HPLC after derivatization with benzoylchloride and was characterized by mass spectrometry. The yields of reacylated lactosylceramide were 38–58% relative to the starting lactosylceramide; the purity of each of the molecular species of lactosylceramide was greater than 95%.
Alkyl glycerol monoethers in the marine spongeDesmapsamma anchorata
Authors: Quijano Leovigildo , Cruz Francisco , Navarrete Irma , Gómez Patricia , Rios Tirso 
Published: November 2006

Abstract1‐O‐Hexadecylglycerol (chimyl alcohol), 1‐O‐heptadecylglycerol and 1‐O‐octadecylglycerol (batyl alcohol) have been identified as the major native constituents of a mixture of free alkyl glycerol ethers isolated from the contained water and the methanolic extract of the spongeDesmapsamma anchorata. Minor components were the free C14, C15, C19, C20 and C21 alkyl glycerol monoethers. The alkyl glycerol monoethers were analyzed and identified by gas chromatography/mass spectrometry of their isopropylidene derivatives. This is the first report on the occurrence of free C15, C19, C20 and C21 alkyl glycerol monoethers in a sponge.
Parametric probabilistic transition systems for system design and analysis
Authors: Lanotte Ruggero , Maggiolo-Schettini Andrea , Troina Angelo 
Published: November 2006

AbstractWe develop a model of parametric probabilistic transition Systems (PPTSs), where probabilities associated with transitions may be parameters. We show how to find instances of the parameters that satisfy a given property and instances that either maximize or minimize the probability of reaching a certain state. As an application, we model a probabilistic non-repudiation protocol with a PPTS. The theory we develop allows us to find instances that maximize the probability that the protocol ends in a fair state (no participant has an advantage over the others).
Aggregation of polyphagous predators in response to multiple prey: ladybirds (Coleoptera: Coccinellidae) foraging in alfalfa
Authors: Evans Edward W. , Toler Trent R. 
Published: November 2006

AbstractThe spatial distribution of polyphagous predators may often reflect the integration of aggregative responses to local densities of multiple species of prey, and as such may have consequences for the indirect linkages among the prey sharing these predators. In a factorial field experiment in which we manipulated local prey densities within a field of alfalfa in Utah (USA), we tested whether aphidophagous ladybirds would aggregate not only in response to their primary aphid prey, but also in response to an abundant alternative prey, the alfalfa weevil (Hypera postica [Gyllenhal]). Native North American ladybirds (primarily Hippodamia convergens Guerin and H. quinquesignata quinquesignata [Kirby]) responded only to spatial variation in aphid density. In contrast, the introduced ladybird, Coccinella septempunctata L., aggregated also at local concentrations of the weevil late in the experiment when weevil density was high and aphid density was relatively low throughout all experimental plots. The results support the hypothesis that C. septempunctata is more responsive than are native ladybirds to the availability of alternative prey in alfalfa, which may account in part for the displacement of native ladybirds from alfalfa by the introduced species as aphid numbers have declined. The differing responses of the native and introduced ladybirds to spatial patterns of the alternative prey underscore the importance of extending the study of predator aggregation to understand better how polyphagous predators distribute themselves in response to spatial patterns of multiple species of potential prey.
Nanocrystal and surface alloy properties of bimetallic Gold-Platinum nanoparticles
Authors: Mott Derrick , Luo Jin , Smith Andrew , Njoki Peter N. , Wang Lingyan , Zhong Chuan-Jian 
Published: November 2006

Abstract
We report on the correlation between the nanocrystal and surface alloy properties with the bimetallic composition of gold-platinum(AuPt) nanoparticles. The fundamental understanding of whether the AuPt nanocrystal core is alloyed or phase-segregated and how the surface binding properties are correlated with the nanoscale bimetallic properties is important not only for the exploitation of catalytic activity of the nanoscale bimetallic catalysts, but also to the general exploration of the surface or interfacial reactivities of bimetallic or multimetallic nanoparticles. The AuPt nanoparticles are shown to exhibit not only single-phase alloy character in the nanocrystal, but also bimetallic alloy property on the surface. The nanocrystal and surface alloy properties are directly correlated with the bimetallic composition. The FTIR probing of CO adsorption on the bimetallic nanoparticles supported on silica reveals that the surface binding sites are dependent on the bimetallic composition. The analysis of this dependence further led to the conclusion that the relative Au-atop and Pt-atop sites for the linear CO adsorption on the nanoparticle surface are not only correlated with the bimetallic composition, but also with the electronic effect as a result of the d-band shift of Pt in the bimetallic nanocrystals, which is the first demonstration of the nanoscale core-surface property correlation for the bimetallic nanoparticles over a wide range of bimetallic composition.
Effect of therapeutic pulsed ultrasound on parameters of oxidative stress in skeletal muscle after injury
Authors: Freitas Luciana S. , Freitas Tiago P. , Silveira Paulo C. , Rocha Luís G. , Pinho Ricardo A. , Streck Emilio L. 
Published: November 2006

AbstractContusion injuries are a very common form of both athletic and non‐athletic injury, that effect muscle function. Treatments to augment the normal repair and regeneration processes are important for a wide variety of patients. Therapeutic ultrasound has been claimed to promote tissue repair, especially by enhancing cell proliferation and protein synthesis. The present study aimed to investigate the effect of therapeutic pulsed ultrasound (TPU) on parameters of oxidative stress, namely thiobarbituric acid‐reactive substances (TBARS), protein carbonyl content and the activities of antioxidant enzymes, catalase and superoxide dismutase (SOD), in skeletal muscle after injury. Wistar rats were submitted to an animal model of muscle (gastrocnemius) laceration. TPU was used once a day. One, three or five days after muscle laceration, the animals were killed by decapitation and oxidative stress parameters were evaluated. Serum CK levels were increased in muscle‐injured animals, indicating that the laceration animal model was successful. TBARS were not altered after muscle injury, when compared to the sham group. Protein carbonyl content was increased after muscle laceration. Catalase and SOD activities were increased 1 day after muscle injury and not altered at days 3 and 5. TPU decreased TBARS levels after muscle laceration when compared to injured muscle animals without treatment. Protein carbonyl content evaluation presented similar results. It is tempting to speculate that TPU seems to protect the tissue from oxidative injury. TPU diminished catalase and SOD activities, especially on the first day following muscle laceration.
Down‐regulation of IGF‐IR using small, interfering, hairpin RNA (siRNA) inhibits growth of human lung cancer cell line A549 in vitro and in nude mice
Authors: Dong Ai‐Qiang , Kong Min‐Jian , Ma Zhi‐Yuan , Qian Jian‐Fang , Xu Xiao‐Hong 
Published: November 2006

AbstractType I insulin‐like growth factor receptor (IGF‐IR), which is frequently overexpressed in a variety of human cancers including lung cancer, mediates cancer cell proliferation and tumor growth. In this study, we used a human U6 promoter‐driven DNA‐template approach to induce hairpin RNA (hpRNA)‐triggered RNAi to silence IGF‐IR gene expression in the human lung cancer cell line A549, and then evaluate its effects on apoptosis, apoptosis‐related gene expression, and the growth of tumor cells in vitro and in nude mice. IGF‐IR expression levels were found to markedly decrease in cells transfected with a plasmid expressing hairpin siRNA for IGF‐IR (by more than 78.9%). Down‐regulation of IGR‐IR concomitantly accompanied reduction of bcl‐2 as well as pERK and pAkt levels, activation of caspase‐3, apoptosis and growth inhibition of A549 cells in vitro. Direct intratumoral injections of plasmid DNA expressing hpRNA for IGF‐IR significantly regressed pre‐established tumors in nude mice. Our results support the therapeutic potential of RNAi as a method for gene therapy in treating lung cancer.
A simple centrifugal dehydration force method to characterize water compartments in fresh and post‐mortem fish muscle
Authors: Cameron Ivan L. , Short Nicholas J. , Fullerton Gary D. 
Published: November 2006

AbstractA centrifugal dehydration force (CDF) method to quantify changes in tissue hydration in fresh and in post‐mortem muscular fish tail tissue is presented. The data obtained were used to assess fluid flow rate from tissues and the size of hydration compartments expressed in g water/g dry mass (DM). Curve fit analysis demonstrated that muscle tissue has three detectable water compartments. Application of the method to the fresh fish indicated the presence of a large non‐bulk water compartment (3.14 g water/g DM) with a much smaller (0.11 g water/g DM) inner non‐bulk water sub‐compartment in addition to a comparatively small bulk water compartment (0.99 g water/g DM). At 10 min and at 4 h post‐mortem, no significant change in size or flow rate of the water compartments was observed. At 24 h post‐mortem the muscular fish tissue, stored in water, swelled with statistically significant increase in total water and in the bulk water compartment but no significant change in the size of the non‐bulk water compartments. The water flow rate from the non‐bulk water compartment was, however, increased significantly in the 24 h dead tissue. This simple CDF method has application for quantization of bulk and non‐bulk water compartments in other biological and non‐biological systems.
Verification of simple hydration/dehydration methods to characterize multiple water compartments on Tendon Type 1 Collagen
Authors: Cameron Ivan L. , Short Nicholas J. , Fullerton Gary D. 
Published: November 2006

AbstractA molecular model of collagen hydration is used to validate centrifugal dehydration force (CDF) and re‐hydration isotherm (RHI) methods to measure and characterize hydration compartments on bovine tendon. The CDF method assesses fluid flow rate from flexor and extensor tendons expressed in (g‐water/g‐dry mass‐minute) and hydration capacity of compartments in (g‐water/g‐dry mass). Measured water compartment capacities agree with the molecular model of collagen hydration [Fullerton GD, Rahal A. Collagen structure: the molecular source of tendon magic angle effect. J Mag Reson Imag 2007;25:345–361; Fullerton GD, Amurao MR. Evidence that collagen and tendon have monolayer water coverage in the native state. Cell Biol Int 2006;30(1):56–65]. Native tendon hydration has monolayer coverage on collagen h
m= 1.6 g/g which divides into primary hydration on polar surfaces hpp= 0.8 g/g and secondary hydration hs= 0.8 g/g bridging over hydrophobic surfaces. Primary hydration is hydrogen bonded tocollagen polar side chains hpsc= 0.54 g/g with small free energy or to the protein main chain hydration hpmc= 0.26 g/g with greater free energy of binding. The CDF method replaces the more time consuming water proton NMR spin‐lattice dehydration (NMR titration) method, confirms the presence ofthree non‐bulk water compartments on collagen (hpmc= 0.26 g/g, hpp= 0.8 g/g and hm= 1.6 g/g). This CDF method provides the most reproducible experimental measure of total tissue non‐bulk water (TNBW). The re‐hydration isotherm method, on the other hand, provides the most accurate measure of the Ramachandran water‐bridge capacity hRa= 0.0656 g/g. The only equipment needed are: microfilterfuge tubes, a microcentrifuge capable of 14,000 × g or 4 MPa, a vacuum drying oven, an accurate balance and curve fitting ability. The newly validated methods should be useful for characterizing multiple water compartments in biological and non‐biological materials by allowing direct measurement of water compartment changes induced by pH, co‐solute salt, glycation and protein cross‐linking.