bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fatty acid and product selectivities of potato tuber lipid acyl hydrolase in esterification reactions with glycerol in organic media
Authors: Pinsirodom Praphan , Parkin Kirk L. 
Published: May 2007

AbstractFatty acid [FA; butanoic (C4); octanoic (C8); tetradecanoic (C14); and cis‐9,12‐octadecadienoic (C18:2) acids] reaction selectivity and the corresponding acyl profiles in differentially accumulating acylglycerol (AG) products (mono‐, di‐, and triacylglycerols; MAG, DAG, TAG, respectively) were evaluated for Celite™‐immobilized potato tuber lipid acyl hydrolase (LAH)‐mediated esterification reactions in isooctane at 35°C and water activity of 0.19. The ordinal pattern of FA selectivities was C8>C14>C18:2>C4, and the AG products accumulating were α‐MAG>DAG>β‐MAG>TAG. A dimensionless expression for fatty acid partitioning coefficient (FAPC) was contrived to represent the partitioning patterns of specific FA into specific AG pools on the basis of an equivalent extent of FA reaction. These FAPC values indicated that preferential partitioning of FA was as follows: C4 was preferentially partitioned into TAG, DAG, and β‐MAG; C8 was preferentially partitioned into DAG; C14 was preferentially partitioned into α,β‐MAG; C18:2 was preferentially partitioned into α,β‐MAG and TAG. These findings infer that the tendency for LAH‐mediated esterifications to accumulate MAG is based, in part, on a constraint in reactivity of α‐MAG of ≥10 acyl carbon groups to serve as acceptors for further esterification events. The general approach taken in this study may assist in identifying the discrete steps in assembling structured glycerides where different biocatalysts exhibit the greatest degree or control of reaction selectivity.
Alkylguanidine‐catalyzed heterogeneous transesterification of soybean oil
Authors: Sercheli Ricardo , Matheus Vargas Rogério , Schuchardt Ulf 
Published: May 2007

AbstractTransesterification of soybean oil with methanol has been carried out in the presence of heterogenized alkylguanidines as catalysts. The alkylguanidines were anchored to modified polystyrene or siliceous MCM‐41, encapsulated in the supercages of zeolite Y, or entrapped in SiO2 sol‐gel matrices. The catalytic activity of these catalysts was compared with that of their homogeneous counterparts, showing that the yields of methyl esters obtained in the homogeneous phase can be obtained with the guanidines anchored to the supports after longer reaction times. The catalysts prepared by immobilization of alkylguanidines in microporous systems showed diffusion restrictions for the vegetable oil as well as the low stability of the inorganic framework.
Matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry of Vernonia galamensis oil
Authors: Ayorinde Folahan O. , Elhilo Eisa , Hlongwane Caswell , Saeed Kamal A. 
Published: May 2007

AbstractMatrix‐assisted laser desorption/ionization (MALDI) time‐of‐flight (TOF) mass spectrometry (MS) has been used to identify eight triacylglycerols (TAG) in Vernonia galamensis oil (VO). The TAG include trivernolin, divernoloylstearoylglycerol, divernoloyloleoylglycerol, vernoloyllinoleoylstearoylglycerol, vernoloyllinoleoyloleoylglycerol, and vernoloyldilinoleoylglycerol. Samples for the MALDI/TOF/MS analysis were prepared with alpha‐cyano‐4‐hydroxycinnamic acid (matrix) in an acetonitrile/tetrahydrofuran solvent system. A mol ratio of matrix/VO (44:1) gave reproducible composite spectra, resulting in resolutions greater than 8,000 and signal‐to‐noise ratios of above 1000 for the most abundant molecular species. 1,3‐Dioleoyl‐2‐stearoylglycerol and 1,2‐dioleoyl‐3‐palmitoylglycerol were used as calibration standards.
A population viability analysis (PVA) for Cabot's Tragopan (Tragopan caboti) in Wuyanling, south-east China
Authors: Zhang Yanyun , Zheng Guangmei 
Published: May 2007

AbstractUnderstanding the status of fragmented populations and predicting their fate is an increasingly important part of bird conservation. Population viability analysis (PVA) can help in this process and is widely used for assessing the extinction risk faced by threatened species and for finding the key factors affecting population status and survival prospects. From 1982 to 2004, 14 scientists studied the population of the globally threatened Cabot's Tragopan Tragopan caboti in Wuyanling National Natural Reserve (WNNR), south-east China and collected life-history data on the population. Using VORTEX, we analysed the viability of the population in the reserve and this predicted that the population size will increase for the next 50 years and will then show a very slight decline for the next 50 years. The loss of heterozygosity is predicted to be 14%, suggesting that the population may not be viable in the long term. Sensitivity analyses showed that nest loss is the most important factor affecting population size and the survival probability of the population, which is supported by field studies. Though the new evidence shows that Cabot's Tragopan can build nests in spruce forest successfully, broad-leaf forest is still necessary for them for foraging, especially at some times of the year. The simulation also shows that the probability of survival and the size of the population will decrease markedly if the extent of suitable habitat is reduced even relatively slowly (such as 0.1% per year). Overall, we conclude that the PVA has provided very informative guidance to future management and research on Cabot's Tragopan at Wuyanling National Nature Reserve.
Inhibition of acute nociceptive responses in rats after i.c.v. injection of Thr6‐bradykinin, isolated from the venom of the social wasp, Polybia occidentalis
Authors: Mortari M R , Cunha A O S , Carolino R O G , Coutinho‐Netto J , Tomaz J C , Lopes N P , Coimbra N C , dos Santos W F 
Published: May 2007

Background and purpose:In this work, a neuroactive peptide from the venom of the neotropical wasp Polybia occidentalis was isolated and its anti‐nociceptive effects were characterized in well‐established pain induction models.Experimental approach:Wasp venom was analysed by reverse‐phase HPLC and fractions screened for anti‐nociceptive activity. The structure of the most active fraction was identified by electron‐spray mass spectrometry (ESI‐MS/MS) and it was further assessed in two tests of anti‐nociceptive activity in rats: the hot plate and tail flick tests.Key Results:The most active fraction contained a peptide whose structure was Arg‐Pro‐Pro‐Gly‐Phe‐Thr‐Pro‐Phe‐Arg‐OH, which corresponds to that of Thr6‐BK, a bradykinin analogue. This peptide was given by i.c.v. injection to rats. In the tail flick test, Thr6‐BK induced anti‐nociceptive effects, approximately twice as potent as either morphine or bradykinin also given i.c.v. The anti‐nociceptive activity of Thr6‐BK peaked at 30 min after injection and persisted for 2 h, longer than bradykinin. The primary mode of action of Thr6‐BK involved the activation of B2 bradykinin receptors, as anti‐nociceptive effects of Thr6‐BK were antagonized by a selective B2 receptor antagonist.Conclusions and implications:Our data indicate that Thr6‐BK acts through B2 bradykinin receptors in the mammalian CNS, evoking antinociceptive behaviour. This activity is remarkably different from that of bradykinin, despite the structural similarities between both peptides. In addition, due to the increased metabolic stability of Thr6‐BK, relative to that of bradykinin, this peptide could provide a novel tool in the investigation of kinin pathways involved with pain.British Journal of Pharmacology (2007) 151, 860–869; doi:10.1038/sj.bjp.0707275
Molecular expression and pharmacological identification of a role for Kv7 channels in murine vascular reactivity
Authors: Yeung S Y M , Pucovský V , Moffatt J D , Saldanha L , Schwake M , Ohya S , Greenwood I A 
Published: May 2007

Background and purpose:This study represents a novel characterisation ofKCNQ‐encoded potassium channels in the vasculature using a variety of pharmacological and molecular tools to determine their role in contractility.Experimental approach:Reverse transcriptase polymerase chain reaction (RT‐PCR) experiments were undertaken on RNA isolated from mouse aorta, carotid artery, femoral artery and mesenteric artery using primers specific for all knownKCNQgenes. RNA isolated from mouse heart and brain were used as positive controls. Pharmacological experiments were undertaken on segments from the same blood vessels to determine channel functionality. Immunocytochemical experiments were performed on isolated myocytes from thoracic aorta.Key results:All blood vessels expressedKCNQ1,4and5with hitherto ‘neuronal’KCNQ4being, surprisingly, the most abundant. The correlated proteins Kv7.1, Kv7.4 and Kv7.5 were identified in the cell membranes of aortic myocytes by immunocytochemistry. Application of three compounds known to activate Kv7 channels, retigabine (2 –20 μM), flupirtine (20 μM) and meclofenamic acid (20 μM), relaxed vessels precontracted by phenylephrine or 1 mM 4‐aminopyridine but had no effect on contractions produced by 60 mM KCl or the Kv7 channel blocker XE991 (10 μM). All vessels tested contracted upon application of the Kv7 channel blockers XE991 and linopirdine (0.1‐10 μM).Conclusions and implications:Murine blood vessels exhibit a distinctiveKCNQexpression profile with ‘neuronal’KCNQ4dominating. The ion channels encoded byKCNQgenes have a crucial role in defining vascular reactivity as Kv7 channel blockers produced marked contractions whereas Kv7 channel activators were effective vasorelaxants.British Journal of Pharmacology(2007)151, 758–770; doi:10.1038/sj.bjp.0707284
Characterization of spinal α‐adrenergic modulation of nociceptive transmission and hyperalgesia throughout postnatal development in rats
Authors: Walker S M , Fitzgerald M 
Published: May 2007

Background and purpose:The selective α2‐adrenergic agonist dexmedetomidine is used clinically for analgesia and sedation, but effects in early life are not well characterized. Investigation of age‐related effects of dexmedetomidine is important for evaluating responses to exogenously administered analgesics and provides insight into postnatal function of noradrenergic pathways.Experimental Approach:We examined effects of epidural dexmedetomidine in anaesthetized rat pups (3, 10 and 21 postnatal days) using a quantitative model of nociception and C‐fibre induced hyperalgesia. Electromyographic recordings of withdrawal responses to hindpaw mechanical stimuli measured effects of dexmedetomidine upon the baseline reflex and the response to mustard oil application on the hindpaw (primary hyperalgesia) or hindlimb (secondary hyperalgesia). In addition, we compared epidural with systemic administration, examined effects of spinal transection and evaluated heart rate changes following dexmedetomidine.Key Results:Epidural dexmedetomidine dose‐dependently prevented mustard oil‐induced hyperalgesia at all ages but dose requirements were lower in the youngest pups. Higher doses also suppressed the baseline nociceptive reflex when given epidurally, but had no effect when given systemically. Analgesic efficacy was the same for primary and secondary hyperalgesia, and was not diminished by spinal cord transection.Conclusions and Implications:Our laboratory studies predict that spinally mediated α2‐agonist analgesia would be effective throughout postnatal development, dose requirements would be lower in early life and selective anti‐hyperalgesic effects could be achieved with epidural administration at doses lower than associated with antinociceptive or cardiovascular effects. Clinical trials of α2agonists in neonates and infants should consider developmentally regulated changes.British Journal of Pharmacology(2007)151, 1334–1342; doi:10.1038/sj.bjp.0707290
Combined pharmacological block of IKr and IKs increases short‐term QT interval variability and provokes torsades de pointes
Authors: Lengyel C , Varró A , Tábori K , Papp J G , Baczkó I 
Published: May 2007

Background and purpose:Assessing the proarrhythmic potential of compounds during drug development is essential. However, reliable prediction of drug‐induced torsades de pointes arrhythmia (TdP) remains elusive. Along with QT interval prolongation, assessment of the short‐term variability of the QT interval (STV(QT)) may be a good predictor of TdP. We investigated the relative importance of IKs and IKr block in development of TdP together with correlations between QTc interval, QT interval variability and incidence of TdP.Experimental approach:ECGs were recorded from conscious dogs and from anaesthetized rabbits given the IKr blocker dofetilide (DOF), the IKs blocker HMR‐1556 (HMR) and their combination, intravenously. PQ, RR and QT intervals were measured and QTc and short‐term variability of RR and QT intervals calculated.Key results:DOF increased QTc interval by 20% in dogs and 8% in rabbits. HMR increased QTc in dogs by 12 and 1.9% in rabbits. Combination of DOF+HMR prolonged QTc by 33% in dogs, by 16% in rabbits. DOF or HMR given alone in dogs or HMR given alone in rabbits induced no TdP. Incidence of TdP increased after DOF+HMR combinations in dogs (63%) and following HMR+DOF (82%) and DOF+HMR combinations (71%) in rabbits. STV(QT) markedly increased only after administration of DOF+HMR combinations in both dogs and rabbits.Conclusion and implications:STV(QT) was markedly increased by combined pharmacological block of IKr and IKs and may be a better predictor of subsequent TdP development than the measurement of QTc interval prolongation.British Journal of Pharmacology (2007) 151, 941–951; doi:10.1038/sj.bjp.0707297
Treprostinil potentiates the positive inotropic effect of catecholamines in adult rat ventricular cardiomyocytes
Authors: Fontana M , Olschewski H , Olschewski A , Schlüter K‐D 
Published: May 2007

Background and purpose:Prostanoids have been shown to improve exercise tolerance, hemodynamics and quality of life in patients with pulmonary arterial hypertension (PAH). We investigated whether treprostinil exerts direct contractile effects on cardiomyocytes that may explain partly the beneficial effects of these drugs.Experimental approach:Ventricular cardiomyocytes from adult rats were paced at a constant frequency of 0.5 to 2.0 Hz and cell shortening was monitored via a cell edge detection system. Twitch amplitudes, expressed as percent cell shortening of the diastolic cell length, and maximal contraction velocity, relaxation velocity, time to peak of contraction and time to reach 50% of relaxation were analyzed.Key results:Treprostinil (0.15 – 15 ng ml−1) slightly increased contractile dynamics of cardiomyocytes at clinically relevant concentrations. However, the drug significantly improved cell shortening of cardiomyocytes in the presence of isoprenaline, a β‐adrenoceptor agonist. Treprostinil exerted this effect at all beating frequencies under investigation. Treprostinil mimicked this potentiating effect in a Langendorff preparation as well. The potentiating effect of treprostinil on isoprenaline‐dependent cell shortening was no longer seen after phosphodiesterase inhibition. Long‐term cultivation of cardiomyocytes with treprostinil did not modify load free cell shortening of these cells, but reduces the duration of contraction.Conclusions and implications:We conclude that the clinically used prostanoid treprostinil potentiates the positive inotropic effects of catecholamines in adult ventricular cardiomyocytes. This newly described effect may contribute to the beneficial clinical effects of prostanoids in patients with PAH.British Journal of Pharmacology (2007) 151, 779–786; doi:10.1038/sj.bjp.0707300
Chemogenomic approaches to drug discovery: similar receptors bind similar ligands
Authors: Klabunde T 
Published: May 2007

Within recent years, a paradigm shift from traditional receptor‐specific studies to a cross‐receptor view has taken place within pharmaceutical research to increase the efficiency of modern drug discovery. Receptors are no longer viewed as single entities but grouped into sets of related proteins or receptor families that are explored in a systematic manner. This interdisciplinary approach attempting to derive predictive links between the chemical structures of bioactive molecules and the receptors with which these molecules interact is referred to as chemogenomics. Insights from chemogenomics are used for the rational compilation of screening sets and for the rational design and synthesis of directed chemical libraries to accelerate drug discovery.British Journal of Pharmacology (2007) 152, 5–7; doi:10.1038/sj.bjp.0707308
Therapeutic treatment with poly(ADP‐ribose) polymerase inhibitors attenuates the severity of acute pancreatitis and associated liver and lung injury
Authors: Mota R , Sánchez‐Bueno F , Berenguer‐Pina J J , Hernández‐Espinosa D , Parrilla P , Yélamos J 
Published: May 2007

Background and purpose:The mortality associated with acute pancreatitis (AP) is largely attributable to abnormalities that occur in distant organs and supportive care remains the only treatment for patients with these complications. Recently, prophylactic pharmacological blockade of poly(ADP‐ribose) polymerase (PARP) enzymes has been shown to attenuate the severity of the disease. However, the clinical relevance of PARP inhibitors administered after the onset of AP remains uncertain. The aim of the present study was to investigate the therapeutic effects of PARP inhibitors in established AP.Experimental approach:Mice were fed a choline/methionine‐deficient/ethionine‐supplemented (CMDE) diet to induce AP. PARP inhibitors were given at 36 h after the onset of CMDE diet. Severity of pancreatitis was assessed by measurements of serum amylase, lipase, IL‐1β and IL‐6, and histological grading. Serum hepatic enzymes, myeloperoxidase (MPO) activity and morphological changes were measured as indicators of hepatic insult. Lung injury was evaluated by MPO activity and morphological changes. Survival rates of mice were monitored for 7 days.Key results:CMDE diet administration resulted in a significant increase in serum amylase, lipase, IL‐1β, IL‐6, alanine aminotransferase and aspartate aminotranferase levels, indicating AP and associated liver injury. Analysis of the histopathological changes in pancreas, liver and lung revealed extensive tissue damage. Treatment of mice with PARP‐inhibitors after the onset of AP was associated with a reduction in the severity of AP and, accordingly, with a reduced mortality rate.Conclusions and Implications:Our results support the therapeutic application of PARP inhibitors in the treatment of established AP.British Journal of Pharmacology (2007) 151, 998–1005; doi:10.1038/sj.bjp.0707310
The SkyMapper Telescope and The Southern Sky Survey
Authors: Keller S. C. , Schmidt B. P. , Bessell M. S. , Conroy P. G. , Francis P. , Granlund A. , Kowald E. , Oates A. P. , Martin-Jones T. , Preston T. , Tisserand P. , Vaccarella A. , Waterson M. F. 
Published: May 2007

AbstractThis paper presents the design and science goals for the SkyMapper telescope. SkyMapper is a 1.3-m telescope featuring a 5.7-square-degree field-of-view Cassegrain imager commissioned for the Australian National University's Research School of Astronomy and Astrophysics. It is located at Siding Spring Observatory, Coonabarabran, NSW, Australia and will see first light in late 2007.The imager possesses 16 384 × 16 384 0.5-arcsec pixels. The primary scientific goal of the facility is to perform the Southern Sky Survey, a six-colour and multi-epoch (four-hour, one-day, one-week, one-month and one-year sampling) photometric survey of the southerly 2π sr to g ∼23 mag. The survey will provide photometry to better than 3% global accuracy and astrometry to better than 50 milliarcsec. Data will be supplied to the community as part of the Virtual Observatory effort. The survey will take five years to complete.
Asymmetry in the time‐lapse seismic response to injection and depletion
Authors: Sayers Colin M. 
Published: May 2007

ABSTRACTLarge changes in seismic reflection amplitude have been observed around injectors, and result from the decrease in elastic‐wave velocity due to the increase in pore pressure in the reservoir. In contrast, the velocity change resulting from the decrease in pore pressure in depleting reservoirs is observed to be smaller in magnitude. Elastic‐wave velocities in sandstones vary with stress due to the presence of stress‐sensitive grain boundaries within the rock. Grain‐boundary stiffness increases non‐linearly with increasing compressive stress, due to increased contact between opposing faces of the boundary. This results in a change in velocity due to a decrease in pore pressure that is smaller than the change in velocity caused by an increase in pore pressure, in agreement with time‐lapse seismic observations. The decrease in porosity resulting from depletion is not fully recovered upon re‐pressurization, and this leads to an additional steepening of the velocity vs. effective stress curve for injection relative to depletion. This difference is enhanced by any breakage of cement or weakening of grain contacts that may occur during depletion and by the reopening or formation of fractures or joints and dilation of grain boundaries that may occur during injection.
Microbial control of phosphate in the nutrient‐depleted North Atlantic subtropical gyre
Authors: Zubkov Mikhail V. , Mary Isabelle , Woodward E. Malcolm S. , Warwick Phillip E. , Fuchs Bernhard M. , Scanlan David J. , Burkill Peter H. 
Published: May 2007

SummaryLittle is known about the dynamics of dissolved phosphate in oligotrophic areas of the world's oceans, where concentrations are typically in the nanomolar range. Here, we have budgeted phosphate uptake by the dominant microbial groups in order to assess the effect of the microbial control of this depleted nutrient in the North Atlantic gyre. Low concentrations (2.2 ± 1.2 nM) and rapid microbial uptake (2.1 ± 2.4 nM day−1) of bioavailable phosphate were repeatedly determined in surface waters of the North Atlantic oligotrophic gyre during spring and autumn research cruises, using a radiotracer dilution bioassay technique. Upper estimates of the concentration of bioavailable phosphate were 7–55% of the dissolved mineral phosphate suggesting that a considerable part of the chemically measured nanomolar phosphate was in a form unavailable for direct microbial uptake. A 1:1 relationship (r2 = 0.96, P < 0.0001) was observed between the bioavailable total phosphate uptake and the phosphate uptake of all the flow sorted bacterioplankton cells, demonstrating that bacterioplankton were the main consumers of phosphate. Within the bacterioplankton a group of heterotrophic bacteria and Prochlorococcus phototrophic cyanobacteria, were the two major competing groups for bioavailable phosphate. These heterotrophic bacteria had low nucleic acid content and 60% of them comprised of SAR11 clade cells based on the results of fluorescence in situ hybridization. Each of the two competing bacterial groups was responsible for an average of 45% of the phosphate uptake, while Synechococcus cyanobacteria (7%) and picoplanktonic algae (0.3%) played minor roles in direct phosphate uptake. We have demonstrated that phosphate uptake in the oligotrophic gyre is rapid and dominated by two bacterial groups rather than by algae.