bluuebunny/crossref_metadata_2025_split huggingface dataset:
The use of 1H NMR for yield determination in the regioselective epoxidation of squalene
Authors: Aerts Hans A. J. , Sels Bert F. E. , Jacobs Pierre A. 
Published: November 2006

Abstract1H NMR can be used to determine the epoxide yield rapidly in the oxidation of squalene. Moreover, unequivocal distinction can be made between internal and terminal epoxide bonds. To underline the power of this technique, different stoichiometric and catalytic epoxidation procedures were carried out using squalene as substrate. They were characterized in terms of substrate conversion and regioselectivity of the epoxide fraction.
The role of endogenous amphiphiles on the stability of virgin olive oil‐in‐water emulsions
Authors: Sotiroudis T. G. , Sotiroudis G. T. , Varkas N. , Xenakis A. 
Published: November 2006

AbstractStable virgin olive oil‐in‐water emulsions were prepared using total endogenous surface‐active components derived from oil as emulsifying agents, and the interfacial properties of the emulsion droplets were examined. The amount of oil extracted into the aqueous buffer increased with buffer pH, with the most stable emulsions being formed at pH 7.5. Light microscopy of the emulsions revealed the presence of spherical droplets with diameters ranging from 1.5 to 3 μm. Their surface was negatively charged at pH 7.5, as confirmed by the effect of ions and polycations. Potassium chloride, Ca2+, and spermine induced rapid aggregation (as monitored by the turbidity change and by light microscopy), showing their maximal effect at 1 M, 4 mM, and 60 μM, respectively. Papain treatment of the emulsion particles rapidly induced particle aggregation, suggesting the destruction of stabilizing structural olive oil proteins. Unlike papain, treatment with phospholipase C did not result in an appreciable turbidity change. Treatment with soybean lipoxygenase slightly increased the turbidity of the emulsion. The interaction of linoleate‐Tween 20 mixed micelles with emulsion droplets produced turbidity, which was maximal at a neutral pH, whereas interaction with proteolyzed and lipoxygenase‐treated droplets induced both a significant increase in turbidity and a red shift to a different absorption maximum of the system as compared with those of the untreated emulsion.
Enzymatic incorporation of stearic acid into a blend of palm olein and palm kernel oil: Optimization by response surface methodology
Authors: Lumor Stephen E. , Akoh Casimir C. 
Published: November 2006

AbstractResponse surface methodology was used to model the incorporation of stearic acid into a blend of palm olein and palm kernel oil in hexane using the sn‐1,3‐regiospecific lipase Lipozyme RM IM. The factors investigated were incubation time, temperature, and substrate molar ratio. A second‐order model with interaction was used to fit the experimental data. The coefficients of determination, R2 and Q2, were 0.96 and 0.90, respectively. The adjusted R2 was 0.95. The regression probability was less than 0.001, and the model showed no lack of fit. Also, a linear relationship was observed between the predicted and observed values. All parameters studied had positive effects on incorporation of stearic acid, with substrate molar ratio having the greatest effect. The interaction terms of substrate molar ratio with temperature and time also had positive effects on incorporation, whereas the effect of the squared term of substrate molar ratio was negative. The quadratic terms of temperature and time, as well as their interaction term, had no significant effect on incorporation at α0.05. Model verification was done by performing a chi‐square test, which showed that there was no significant difference between predicted values and a new set of observed responses.
Enrichment of CLA isomers by selective esterification with l‐menthol using Candida rugosa lipase
Authors: Kobayashi Takashi , Nagao Toshihiro , Watanabe Yomi , Yamauchi‐Sato Yoshie , Negishi Satoshi , Shimada Vuji 
Published: November 2006

AbstractCommercially available preparations of CLA are composed of almost equal amounts of 9‐cis,11‐trans (9c,11t)‐CLA and 10‐trans,12‐cis (10t,12c)‐CLA. Each isomer was fractionated and enriched, for availability as a food supplement, by a process comprising selective esterification with l‐menthol by Candida rugosa lipase, distillation, and n‐hexane extraction. The first selective esterification of CLA isomers was conducted with an equimolar amount of l‐menthol of 30°C. The oil phase of the reaction mixture was fractionated into an l‐menthyl ester fraction (9c,11t‐CLA rich) and an FFA fraction (10t,12c‐CLA rich) by distillation. The FFA fraction was esterified again with an equimolar amount of l‐menthol to enrich 10t,12c‐CLA. The 10t,12c‐CLA preparation was obtained as the resulting FFA fraction by distillation. 10t,12c‐CLA was enriched to 91% with 40% recovery. To enrich 9c,11t‐CLA, the l‐menthyl ester fraction in the first esterification was chemically hydrolyzed, and the resulting FFA were esterified again with an equimolar amount of l‐menthol. The 9c, 11t‐CLA preparation was obtained by chemical hydrolysis of the resulting l‐methyl ester fraction, followed by n‐hexane extraction. 9c,11t‐CLA was enriched to 94% with 42% recovery. This effective process for purification of CLA isomers using l‐methol is applicable to the production of food supplements.
Ceramer coatings from castor oil or epoxidized castor oil and tetraethoxysilane
Authors: de Luca Maria Augusta , Martinelli Márcia , Jacobi Marly Maldaner , Becker Patrícia Luíza , Ferrão Marco Flores 
Published: November 2006

AbstractNew inorganic‐organic hybrids were synthesized through the reaction of castor oil (CO) or epoxidized castor oil (ECO) with tetraethoxysilane (TEOS). The mass proportions of ECO/TEOS varied from 90∶10 to 60∶40, and films of the material were thermally cured. An IR spectroscopy analysis was performed, and macro‐ and microscopic properties such as adhesion, hardness, swelling in toluene, microstructure (scanning electron microscopy), and Tg were investigated as a function of the proportion of their inorganic‐organic precursor. Morphologic studies showed that the hybrid films were homogeneous when lower proportions of the inorganic precursors were used. Hardness and tensile strength increased with TEOS concentration, whereas swelling in toluene decreased with TEOS concentration. Good adhesion was observed throughout the hybrid series.
Solvent extraction of ethanol from aqueous solutions using biobased oils, alcohols, and esters
Authors: Offeman Richard D. , Stephenson Serena K. , Robertson George H. , Orts William J. 
Published: November 2006

AbstractDistribution coefficients and separation factors were determined for the partitioning of ethanol and water from aqueous mixtures into several vegetable oils and their fatty alcohol and fatty ester derivatives. Castor oil, ricinoleyl alcohol, and methyl ricinoleate all show higher ethanol distribution coefficients, and similar or reduced separation factors, relative to other oils and derivatives studied here or reported by others. Of particular interest, ricinoleyl alcohol has an ethanol distribution coefficient 50% higher than that of oleyl alcohol, a commonly studied solvent for ethanol extraction from fermentation broths.
A quantitative colorimetric method of measuring alkaline phosphatase activity in eukaryotic cell membranes
Authors: Akcakaya Handan , Aroymak Aysin , Gokce Sina 
Published: November 2006

AbstractAlkaline phosphatase (ALP) is glycoprotein structured metalophosphatase with several defined functions. It is present in many tissues of all living beings from bacteria to mammals. The enzyme may catalyse the hydrolysis of various monophosphate esters at alkaline pH. The objective of this study was to quantify ALP functioning particularly in the membranes of eukaryotic cells. The membranes of seven different cells (myeloma cells; hybrid cells; erythroleukaemia cells; lymphocytes and erythrocytes) were tested for ALP activity using a cellular enzyme assay, which is based on the conversion of para‐nitrophenylphosphate (p‐NPP) to para‐nitrophenol and the colorimetric determination of the resulting coloured product. The test system was optimised with respect to substrate concentration, reaction time and the number of cells used as a source of enzyme. The obtained values were converted to quantitative results through a standard curve created using commercial ALP. In order to determine the effect of serum concentration on enzyme activity, 1G2 hybridoma, which is among the cells used in this study and which synthesizes monoclonal antibody against human serum albumin, was produced in different serum concentrations ranging from 0 to 15%.
In situ trapping of initiator caspases reveals intermediate surprises
Authors: Mohr Andrea , Zwacka Ralf M. 
Published: November 2006

AbstractA novel method to identify initiator caspases is an in situ trapping approach using a cell‐permeable biotinylated caspase inhibitor valine‐alanine‐aspartate‐fluoromethyl ketone (bVAD) that binds covalently and irreversibly to the active cysteine site of caspases. This inhibits apoptosis and should allow precipitation of initiator caspases in their uncleaved forms. However, in our experiments TRAIL and FasL‐induced apoptosis and bVAD labelling did not result in streptavidin precipitation of the procaspase‐8 forms, but led to the pull‐down of the intermediate and to a lesser extent fully cleaved forms (p41/43 and p18). These findings are contrary to other reports and are of relevance to apoptosis research as they challenge the general concept of the bVAD approach that procaspases are being trapped. We show that (partially) processed forms of initiator caspases rather than procaspases might be precipitated with this method.
Relevance of apoptosis in influencing recovery of hibernating myocardium
Authors: Angelini Annalisa , Maiolino Giuseppe , La Canna Giovanni , Ceconi Claudio , Calabrese Fiorella , Pettenazzo Elena , Valente Marialuisa , Alfieri Ottavio , Thiene Gaetano , Ferrari Roberto 
Published: November 2006

AbstractBackground:Hibernating myocardium (HM) is viable but dysfunctional myocardium which can recover following revascularization. Myocyte necrosis is virtually absent in HM; however, cellular loss may take place by apoptosis, although this is controversial.Aim:To assess the presence of apoptosis and its relevance in HM.Methods:During coronary artery by‐pass surgery (CABG), 21 patients underwent transmural biopsy in the dysfunctional left anterior descending artery tributary area of the left ventricle (LV), with kinetic recovery at follow‐up, thus fulfilling the HM criteria. All patients underwent echocardiographic follow‐up at 12 months. All biopsies were evaluated by light microscopy, electron microscopy (EM), and molecular analysis.Results:All biopsies were structurally altered, showing increased fibrosis and myocytes with variable size. Myocyte dedifferentiation was not detected by immunohistochemistry or EM. On stepwise linear regression, 1 year LVEF was predicted by the apoptotic index (β=−0.973, p=0.002), the normotrophic cell percentage (β=0.449, p=0.038), and mean fibrosis (β=−0.412, p=0.51).Conclusions:Our biopsy study detected a wide range of morphological substrate heterogeneity in HM with degenerative features. We have demonstrated for the first time in humans that myocyte apoptosis is an important phenomenon in HM, negatively influencing LV functional recovery after CABG.
Endogenous inhibitors of hypertrophy in concentric versus eccentric hypertrophy
Authors: Lemmens Katrien , Segers Vincent F.M. , Demolder Marc , Michiels Maria , Van Cauwelaert Philip , De Keulenaer Gilles W. 
Published: November 2006

AbstractLeft ventricular (LV) hypertrophy (LVH) is an adaptive response to hemodynamic overload, but also contributes to the pathogenesis of heart failure. LVH can be concentric (cLVH) but subsequent dilatation and progression to eccentric hypertrophy (eLVH) may lead to global pump failure. Recently, several endogenous molecular inhibitors of hypertrophy have been identified. Using real‐time PCR, we compared the myocardial mRNA expression of these inhibitors in pressure‐overload induced cLVH (severe aortic stenosis) and in volume overload‐induced eLVH (severe mitral regurgitation) in patients, and during the progression from cLVH to eLVH in pressure overload in rat. Each of these genes showed a unique temporal expression profile. Strikingly, except for SOCS‐3, changes in gene expression of these negative regulators in rat cLVH and eLVH vs sham were recapitulated in human cLVH and eLVH. In particular, VDUP‐1 and MCIP‐1 were high in cLVH but expression levels were normal in eLVH, both in rat and human. These data indicate that during the progression of LVH, both in pressure and volume overload, expression levels of endogenous inhibitors of hypertrophy are modified and that these changes may have pathophysiological significance. In particular, MCIP‐1 (the endogenous calcineurin inhibitor) and VDUP‐1 (the endogenous inhibitor of thioredoxin) are potential molecular switches in the progression of LV hypertrophy.
Shared executive dysfunctions in unaffected relatives of patients with autism and obsessive-compulsive disorder
Authors: Delorme Richard , Goussé Véronique , Roy Isabelle , Trandafir Anca , Mathieu Flavie , Mouren-Siméoni Marie-Christine , Betancur Catalina , Leboyer Marion 
Published: November 2006

AbstractBackgroundExecutive dysfunctions have been studied as a potential endophenotype associated with the genetic basis of autism. Given that recent findings from clinical and molecular genetic studies suggest that autism and obsessive-compulsive disorder (OCD) could share a common pattern of heritability, we assessed executive functions as a possible common cognitive endophenotype in unaffected family members of individuals with either autism or OCD.MethodsFive tests assessing executive functions (Tower of London, verbal fluency, design fluency, trail making and association fluency) were proposed to 58 unaffected first-degree relatives (parents and siblings) of probands with autism and 64 unaffected first-degree relatives of OCD patients. Results were compared with those of 47 healthy controls matched for age, sex, and level of education.ResultsIn the Tower of London test, both groups of unaffected relatives showed significantly lower scores and longer response times compared with controls. No differences were observed between autism and OCD relatives and healthy controls in the four other tasks (verbal fluency, design fluency, trail making test and association fluency).ConclusionsOur findings show the existence of executive dysfunction in the unaffected first-degree relatives of probands with OCD, similar to those observed in the relatives of patients with autism. These results support and extend previous cognitive studies on probands indicating executive dysfunctions in autism and OCD. Planning and working memory processes could thus represent a common cognitive endophenotype in autism and OCD that could help in the identification of genes conferring vulnerability to these disorders.
Sustained and selective attention deficits as vulnerability markers to psychosis
Authors: Mulet B. , Valero J. , Gutiérrez-Zotes A. , Montserrat C. , Cortés M.J. , Jariod M. , Martorell L. , Vilella E. , Labad A. 
Published: November 2006

AbstractThe first descriptions of schizophrenia emphasized attention problems patients with schizophrenia have but recent results evidence that other psychotic disorders share them.We compared the performance in sustained and selective attention between psychotic patients (P), their healthy first degree relatives (R) and healthy volunteers (C) to prove whether these alterations could be an endophenotype of vulnerability to psychosis. We also compared the performance of schizophrenic patients (SZP) and that of patients with other functional psychoses (OP) in order to prove whether these alterations are specific of any psychotic disorder.Seventy-six P, 70 R and 39 C were included in the study. A selective attention index, comprising TMT A and B and Stroop Test, and a sustained attention index comprising the Continuous Performance Test were calculated. We conducted an univariant general linear model to compare three group performances in these indexes, with age, sex and years of education as a covariables.We found significant differences between the indexes when we compared P, R and C. No differences in performance were found between SZP and OP. Our data showed that sustained and selective attention alterations could be a vulnerability factor to psychotic disorders in general, but they were not specific of schizophrenia.
The effects induced by the sulphonylurea glibenclamide on the neonatal rat spinal cord indicate a novel mechanism to control neuronal excitability and inhibitory neurotransmission
Authors: Ostroumov K , Grandolfo M , Nistri A 
Published: November 2006

Background and purpose:Using the neonatal rat spinal cord in vitro, we investigated the action of glibenclamide, a drug possessing dual pharmacological effects, namely block of KATP channels and of the cystic fibrosis transmembrane conductance regulator (CFTR).Experimental approach:Intra‐ and extracellular recordings were performed on motoneurons and interneurons. RT‐PCR and western immunoblotting were used to determine gene and protein expression.Key results:Glibenclamide (50 μM) facilitated mono‐ and polysynaptic reflexes, hyperpolarized motoneuron resting potential, increased action potential amplitude, decreased Renshaw cell‐mediated recurrent inhibition, and increased network excitability by depressing GABA‐ and glycine‐mediated transmission. The action of glibenclamide was mimicked by tolbutamide (500 μM) or the CFTR blocker diphenylamine‐2,2‐dicarboxylic acid (500 μM). The action of glibenclamide was independent from pharmacological inhibition of the Na+–K+ pump with strophanthidin (4 μM) and was associated with a negative shift in the extrapolated reversal potential for CI‐ dependent synaptic inhibition. On interneurons, intracellularly‐applied 8‐bromo‐cAMP elicited an inward current and resistance decrease; effects antagonized by the selective CFTR antagonist, CFTRinh‐172 (5 μM). RT‐PCR and western immunoblotting indicated strong expression of the CFTR in neonatal rat spinal cord.Conclusions and implications:These data suggest the CFTR expressed in motoneurons and interneurons of the neonatal spinal cord is involved in the control of Cl‐ homeostasis and neuronal excitability. CFTR appeared to contribute to the relatively depolarized equilibrium potential for synaptic inhibition, an important process to control hyperexcitability and seizure‐predisposition in neonates.British Journal of Pharmacology (2007) 150, 47–57. doi:10.1038/sj.bjp.0706943
Critical assessment of quantum mechanics based energy restraints in protein crystal structure refinement
Authors: Yu Ning , Li Xue , Cui Guanglei , Hayik Seth A. , Merz Kenneth M. 
Published: November 2006

AbstractA critical evaluation of the performance of X‐ray refinement protocols using various energy functions is presented using the bovine pancreatic trypsin inhibitor (BPTI) protein. The four potential energy functions we explored include: (1) fully quantum mechanical calculations; (2) one based on an incomplete molecular mechanics (MM) energy function employed in the Crystallography and NMR System (CNS) with empirical parameters developed by Engh and Huber (EH), which lacks electrostatic and attractive van der Waals terms; (3) one based on a complete MM energy function (AMBER ff99 parameter set); and (4) the same as 3, with the addition of a Generalized Born (GB) implicit solvation term. The R, R free, real space R values of the refined structures and deviations from the original experimental structure were used to assess the relative performance. It was found that at 1 Å resolution the physically based energy functions 1, 3, and 4 performed better than energy function 2, which we attribute to the better representation of key interactions, particularly electrostatics. The observed departures from the experimental structure were similar for the refinements with physically based energy functions and were smaller than the structure refined with EH. A test refinement was also performed with the reflections truncated at a high‐resolution cutoff of 2.5 Å and with random perturbations introduced into the initial coordinates, which showed that low‐resolution refinements with physically based energy functions held the structure closer to the experimental structure solved at 1 Å resolution than the EH‐based refinements.
Site‐directed mutagenesis indicates an important role of cysteines 76 and 181 in the catalysis of hydantoin racemase from Sinorhizobium meliloti
Authors: Martínez‐Rodríguez Sergio , Andújar‐Sánchez Montserrat , Neira Jose L. , Clemente‐Jiménez Josefa M. , Jara‐Pérez Vicente , Rodríguez‐Vico Felipe , Las Heras‐Vázquez Francisco J. 
Published: November 2006

AbstractHydantoin racemase enzyme plays a crucial role in the reaction cascade known as “hydantoinase process.” In conjunction with a stereoselective hydantoinase and a stereospecific carbamoylase, it allows the total conversion from D,L‐5‐monosubstituted hydantoins, with a low rate of racemization, to optically pure D‐ or L‐amino acids. Residues Cys76 and Cys181 belonging to hydantoin racemase from Sinorhizobium meliloti (SmeHyuA) have been proved to be involved in catalysis. Here, we report biophysical data of SmeHyuA Cys76 and Cys181 to alanine mutants, which point toward a two‐base mechanism for the racemization of 5‐monosubstituted hydantoins. The secondary and the tertiary structure of the mutants were not significantly affected, as shown by circular dichroism. Calorimetric and fluorescence experiments have shown that Cys76 is responsible for recognition and proton retrieval of D‐isomers, while Cys181 is responsible for L‐isomer recognition and racemization. This recognition process is further supported by measurements of protein stability followed by chemical denaturation in the presence of the corresponding compound.
Putative lipoproteins identified by bioinformatic genome analysis of Leifsonia xyli ssp. xyli, the causative agent of sugarcane ratoon stunting disease
Authors: SUTCLIFFE IAIN C. , HUTCHINGS MATTHEW I. 
Published: November 2006

SUMMARY Leifsonia xyli ssp. xyli is the causative agent of ratoon stunting disease, a major cause of economic loss in sugarcane crops. Understanding of the biology of this pathogen has been hampered by its fastidious growth characteristics in vitro. However, the recent release of a genome sequence for this organism has allowed significant novel insights. Further to this, we have performed a bioinformatic analysis of the lipoproteins encoded in the L. xyli genome. These analyses suggest that lipoproteins represent c. 2.0% of the L. xyli predicted proteome. Functional analyses suggest that lipoproteins make an important contribution to the physiology of the pathogen and may influence its ability to cause disease in planta.