bluuebunny/crossref_metadata_2025_split huggingface dataset:
Regulation of phosphoenolpyruvate carboxylase in PVYNTN-infected tobacco plants
Authors: Müller Karel , Doubnerová Veronika , Synková Helena , Čeřovská Noemi , Ryšlavá Helena 
Published: December 2008

Abstract
The effect of viral infection on the regulation of phosphoenolpyruvate carboxylase (PEPC, EC 4.1.1.31) in Nicotiana tabacum L. leaves was studied. PEPC activity was 3 times higher in infected plant leaves compared to healthy plants. Activity of plant PEPC can be regulated, e.g., by de novo synthesis or reversible phosphorylation. The reason for the increase of PEPC activity as a consequence of PVYNTN infection was studied. The amount of PEPC determined by Western blot analysis or by relative estimation of PEPC mRNA by real-time PCR did not differ in control and PVYNTN-infected plants. Changes in post-translational modification of PEPC by phosphorylation were evaluated by comparing activity of the native and the dephosphorylated enzyme. The infected plants were characterized by a higher decrease of the enzyme activity after its dephosphorylation, which indicated a higher phosphorylation level. Immunochemical detection of phosphoproteins by Western blot analysis showed a more intensive band corresponding to PEPC from the infected material. This strengthens the hypothesis of an infection-related phosphorylation, which could be part of the plant's response to pathogen attack. The physiological implications of the increase in PEPC activity during PVYNTN infection are discussed.
Human CYP4Z1 catalyzes the in-chain hydroxylation of lauric acid and myristic acid
Authors: Zöllner Andy , Dragan Calin-Aurel , Pistorius Dominik , Müller Rolf , Bode Helge B. , Peters Frank T. , Maurer Hans H. , Bureik Matthias 
Published: December 2008

Abstract
Overexpression of human CYP4Z1, a cytochrome P450 enzyme, has been correlated with poor prognosis in human cancer. However, its catalytic properties are not yet known. We expressed this P450 in Schizosaccharomyces pombe and demonstrate by whole-cell biotransformation assays CYP4Z1-dependent in-chain hydroxylation of lauric and myristic acid, which in both cases leads to the formation of four different monohydroxylated products at positions ω-2, ω-3, ω-4, and ω-5, respectively. The CYP4Z1-expressing fission yeast should be a new valuable tool for testing cancer drugs or for the development of new prodrug strategies.
Expression and localization of atypical PKC isoforms in liver parenchymal cells
Authors: Stross Claudia , Keitel Verena , Winands Elisabeth , Häussinger Dieter , Kubitz Ralf 
Published: December 2008

Abstract
Members of all three classes of the protein kinase C (PKC) family including atypical PKCzeta (PKCζ) are involved in central functions of liver parenchymal cells. However, expression and localization of PKCiota (PKCι), the highly homologous atypical PKC (aPKC) isoform, in hepatocytes is unknown to date. PKCζ and PKCι were cloned from human and rat liver and fused to fluorescent protein tags (YFP). The sequence of full-length rat PKCι is not yet known and was cloned from cDNA of hepatocytes by the use of degenerated primers. PKCζ-YFP and PKCι-YFP (human and rat) were expressed in HeLa or HEK293 cells and used to test the specificity of seven aPKC antibodies. Two antibodies were PKCι-specific and two were specific for PKCζ in immunofluorescence and Western blot analysis. Subcellular localization was analyzed by immunofluorescence in isolated rat and human hepatocytes and liver sections. Low immunoreactivity for aPKCs was found at the sinusoidal membrane and in the cytosol. The highest density of PKCι as well as PKCζ was found at the canalicular membrane in co-localization with ABC-transporters, such as bile salt export pump or multidrug resistance-associated protein 2. This topology suggests a specific function of aPKCs at the canalicular membrane in addition to their known role in cell polarity of epithelial cells.
Tracing Streamlines on Unstructured Grids From Finite Volume Discretizations
Authors: Matringe S. F. , Juanes R. , Tchelepi H. A. 
Published: December 2008

Summary
The accuracy of streamline reservoir simulations depends strongly on the quality of the velocity field and the accuracy of the streamline tracing method. For problems described on complex grids (e.g., corner-point geometry or fully unstructured grids) with full-tensor permeabilities, advanced discretization methods, such as the family of multipoint flux approximation (MPFA) schemes, are necessary to obtain an accurate representation of the fluxes across control volume faces. These fluxes are then interpolated to define the velocity field within each control volume, which is then used to trace the streamlines. Existing methods for the interpolation of the velocity field and integration of the streamlines do not preserve the accuracy of the fluxes computed by MPFA discretizations.
Here we propose a method for the reconstruction of the velocity field with high-order accuracy from the fluxes provided by MPFA discretization schemes. This reconstruction relies on a correspondence between the MPFA fluxes and the degrees of freedom of a mixed finite-element method (MFEM) based on the first-order Brezzi-Douglas-Marini space. This link between the finite-volume and finite-element methods allows the use of flux reconstruction and streamline tracing techniques developed previously by the authors for mixed finite elements. After a detailed description of our streamline tracing method, we study its accuracy and efficiency using challenging test cases.
Performance of Drainage Experiments With Orinoco Belt Heavy Oil in a Long Laboratory Core in Simulated Reservoir Conditions
Authors: Wang Ruihe , Qin Jishun , Chen Zhangxin , Zhao Ming 
Published: December 2008

Summary
When some heavy-oil reservoirs are produced using gas drive, they show three important features: low production gas/oil ratios, higher-than-expected production rates, and relatively high oil recovery. The mechanism for this unusual behavior remains controversial and poorly understood, though the term "foamy oil" is often used to describe such behavior. The impetus for this work stems from some recent projects performed in the Orinoco belt, Venezuela. There exist nearly one trillion bbl of heavy oil (oil in place) in this region on the basis of a recent evaluation. Two crucial issues must be addressed before or during designing production projects: What is a suitable method for evaluating the foamy-oil drive mechanism that plays a major role during such oil recovery, and how do we obtain a reasonable percentage of ultimate oil recovery? Unfortunately, it is still difficult to give good explanations for these two issues, although several studies were performed. This paper attempts to present better explanations for these two issues using experimental drainage in a long laboratory core in simulated reservoir conditions.
Our experiments show that ultimate oil recovery for the heavy oil in the Orinoco belt can be as high as 15-20%. This high recovery comes from three contributions: fluid and rock expansion, foamy-oil drive, and conventional-solution-gas drive. Approximately 3-5% of recovery is from fluid and rock expansion, 11-16% from foamy-oil drive, and 2-4% from conventional-solution-gas drive. This ultimate-oil-recovery percentage is much higher than the 12% that has been used in the field-development plan for the Orimulsion project. The experiments performed and their findings obtained in this paper are representative at least in the Orinoco belt region.
Optimal synthesis of p‐xylene separation processes based on crystallization technology
Authors: Lima Ricardo M. , Grossmann Ignacio E. 
Published: December 2008

AbstractThis article addresses the synthesis and optimization of crystallization processes for p‐xylene recovery for systems with feed streams of high concentration, a case that arises in hybrid designs where the first step is commonly performed by adsorption. A novel superstructure and its corresponding mixed‐integer nonlinear programming (MINLP) model are proposed. The distinct feature of this superstructure is the capability to generate optimum or near optimum flow sheets for a wide range of specifications of p‐xylene compositions in the feed stream of the process. To cope with the complexity of the MINLP model, a two‐level decomposition approach, consisting of the solution of an aggregated model and a detailed model, is proposed. The results obtained show good performance of the decomposition strategy, and the optimal flow sheets and p‐xylene recoveries are in agreement with the results reported in patents. © 2008 American Institute of Chemical Engineers AIChE J, 2009
Stable intermediates determine proteins' primary unfolding sites in the presence of surfactants
Authors: Hansen Jonas Høeg , Petersen Steen Vang , Andersen Kell Kleiner , Enghild Jan J. , Damhus Ture , Otzen Daniel 
Published: December 2008

AbstractDespite detailed knowledge of the overall structural changes and stoichiometries of surfactant binding, little is known about which protein regions constitute the preferred sites of attack for initial unfolding. Here we have exposed three proteins to limited proteolysis at anionic (SDS) and cationic (DTAC) surfactant concentrations corresponding to specific conformational transitions, using the surfactant‐robust broad‐specificity proteases Savinase and Alcalase. Cleavage sites are identified by SDS‐PAGE and N‐terminal sequencing. We observe well‐defined cleavage fragments, which suggest that flexibility is limited to certain regions of the protein. Cleavage sites for α‐lactalbumin and myoglobin correspond to regions identified in other studies as partially unfolded at low pH or in the presence of organic solvents. For Tnfn3, which does not form partially folded structures under other conditions, cleavage sites can be rationalized from the structure of the protein's folding transition state and the position of loops in the native state. Nevertheless, they are more sensitive to choice of surfactant and protease, probably reflecting a heterogeneous and fluctuating ensemble of partially unfolded structures. Thus, for proteins accumulating stable intermediates on the folding pathway, surfactants encourage the formation of these states, while the situation is more complex for proteins that do not form these intermediates. © 2008 Wiley Periodicals, Inc. Biopolymers 91: 221–231, 2009.This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
IFN‐α‐mediated increase in cytolytic activity of maturing NK cell upon exposure to HSV‐infected myelomonocytes
Authors: Costa Paola , Sivori Simona , Bozzano Federica , Martini Isabella , Moretta Alessandro , Moretta Lorenzo , De Maria Andrea 
Published: December 2008

AbstractImpaired control of chronic pathogen replication may be associated to alterations of NK‐cell function. Whether mechanisms underlying this dysfunction involve perturbations of differentiating NK cells is still unknown. We studied an “in vitro” model of differentiation from CD34+Lin− precursors growing only myelomonocytes and maturing NK cells and where myelomonocytes could be suitably infected with HSV, HIV, or vaccinia. Cultures were evaluated by cytofluorometry and cytotoxicity assays for perturbations in differentiating NK cells. Increased expression of natural cytotoxicity receptors on maturing NK cells with increased cytolytic activity was observed with HSV‐1 infection, and with vaccinia while no modulation of NK‐cell phenotype nor cytotoxic activity were evident with an ssRNA lentivirus (HIV‐1). In the presence of constant IL‐12 and IL‐15 concentrations, the observed effect did not require cell contact, involved IFN‐αand was not reproduced by the addition of TLR9 agonist, nor blocked by TLR9 antagonists. Virus replication at sites of NK‐cell precursor development may have different outcomes depending on the interaction between invading viruses and maturing NK cells. Thus, NK‐cell precursors may be involved in the immune response to dsDNA viruses and possibly contribute to efficient control of virus infection.
Early recruitment of natural CD4+Foxp3+ Treg cells by infective larvae determines the outcome of filarial infection
Authors: Taylor Matthew D. , van der Werf Nienke , Harris Anjanette , Graham Andrea L. , Bain Odile , Allen Judith E. , Maizels Rick M. 
Published: December 2008

AbstractHuman helminth infections are synonymous with impaired immune responsiveness indicating suppression of host immunity. Using a permissive murine model of filariasis, Litomosoides sigmodontis infection of inbred mice, we demonstrate rapid recruitment and increased in vivo proliferation of CD4+Foxp3+ Treg cells upon exposure to infective L3 larvae. Within 7 days post‐infection this resulted in an increased percentage of CD4+T cells at the infection site expressing Foxp3. Antibody‐mediated depletion of CD25+ cells prior to infection to remove pre‐existing ‘natural’ CD4+CD25+Foxp3+ Treg cells, while not affecting initial larval establishment, significantly reduced the number of adult parasites recovered 60 days post‐infection. Anti‐CD25 pre‐treatment also impaired the fecundity of the surviving female parasites, which had reduced numbers of healthy eggs and microfilaria within their uteri, translating to a reduced level of blood microfilaraemia. Enhanced parasite killing was associated with augmented in vitro production of antigen‐specific IL‐4, IL‐5, IL‐13 and IL‐10. Thus, upon infection filarial larvae rapidly provoke a CD4+Foxp3+ Treg‐cell response, biasing the initial CD4+ T‐cell response towards a regulatory phenotype. These CD4+Foxp3+ Treg cells are predominantly recruited from the ‘natural’ regulatory pool and act to inhibit protective immunity over the full course of infection.
The typology of ancient quarries within the Paleocene limestone of Álava in northern Spain
Authors: Martínez‐Torres Luis M. 
Published: December 2008

AbstractPaleocene limestone and dolomitized limestone of Álava, Spain, were used as building materials from the Neolithic age until the Neoclassical, predominantly in the production of headstones, sculpture, and stonework during the Roman era (1st to 4th centuries) and Romanic and Gothic periods (10th to 15th centuries). The quarrying methods employed are related to topographic relief. Five types of ancient quarry have been identified: escarpment, dip‐slope (ascending and descending), edge, and trench. The oldest quarries (1st to 4th centuries) are the trench‐cut stone pits of “Raso de Cezama.” Later, from the Romanic period (10th to 15th centuries), descending dip‐slope, escarpment, and edge‐based quarries were worked, such as those at Achuri, Ajarte, and Santa Elena. Finally, an ascending dip‐slope quarry was developed at Marquínez during the Neoclassical period (18th century). © 2009 Wiley Periodicals, Inc.
Somatic and non‐affective symptoms of old age depression: ethnic differences among Chinese, Indians and Malays
Authors: Soh Keng Chuan , Kua Ee Heok , Ng Tze Pin 
Published: December 2008

AbstractBackgroundSomatic and other non‐affective symptomatology characterizes late life depression and contributes to its under‐diagnosis, especially in some ethnic groups.ObjectivesWe examined variations in non‐affective presentation and its health and functional significance across different ethnic groups of Chinese, Malays and Indians.MethodWe analyzed data from the National Mental Health Survey for Elderly, a population‐based cross‐sectional study of older adults aged 60 and above (N = 1092).ResultsCompared to the depressed Chinese as the reference group, depressed Malays were more likely to endorse symptoms of appetite decrease (OR = 5.19), sleep disturbances (OR = 2.93), disabling pain (OR = 3.12), psychomotor slowing (OR = 2.73) and anergia (OR = 3.70), while concurrently reporting poorer general health status and greater role limitations resulting from their mental and emotional problems (OR from 2.13 to 3.31). These differences were not influenced by anxiety, dementia or physical comorbidity.ConclusionWe revealed striking differences in the somatic and non‐affective symptomatology of geriatric depression among different Asian ethnic groups. Non‐affective symptoms in depression have large health and functional significance and important implications for the diagnosis and management of depression among elderly in primary care. Copyright © 2008 John Wiley & Sons, Ltd.
At the heart of the ventral attention system: The right anterior insula
Authors: Eckert Mark A. , Menon Vinod , Walczak Adam , Ahlstrom Jayne , Denslow Stewart , Horwitz Amy , Dubno Judy R. 
Published: December 2008

AbstractThe anterior insula has been hypothesized to provide a link between attention‐related problem solving and salience systems during the coordination and evaluation of task performance. Here, we test the hypothesis that the anterior insula/medial frontal operculum (aI/fO) provides linkage across systems supporting task demands and attention systems by examining the patterns of functional connectivity during word recognition and spatial attention functional imaging tasks. A shared set of frontal regions (right aI/fO, right dorsolateral prefrontal cortex, bilateral anterior cingulate) were engaged, regardless of perceptual domain (auditory or visual) or mode of response (word production or button press). We present novel evidence that: (1) the right aI/fO is functionally connected with other frontal regions implicated in executive function and not just brain regions responsive to stimulus salience; and (2) that the aI/fO, but not the ACC, exhibits significantly correlated activity with other brain regions specifically engaged by tasks with varying perceptual and behavioral demands. These results support the hypothesis that the right aI/fO aids in the coordination and evaluation of task performance across behavioral tasks with varying perceptual and response demands. Hum Brain Mapp 2009. © 2008 Wiley‐Liss, Inc.
Neural substrates of low‐frequency repetitive transcranial magnetic stimulation during movement in healthy subjects and acute stroke patients. A PET study
Authors: Conchou Fabrice , Loubinoux Isabelle , Castel‐Lacanal Evelyne , Le Tinnier Anne , Gerdelat‐Mas Angélique , Faure‐Marie Nathalie , Gros Helene , Thalamas Claire , Calvas Fabienne , Berry Isabelle , Chollet François , Simonetta Moreau Marion 
Published: December 2008

AbstractThe aim of the study was to investigate, with an rTMS/PET protocol, the after‐effects induced by 1‐Hz repetitive transcranial magnetic stimulation (rTMS) in the regional cerebral blood flow (rCBF) of the primary motor cortex (M1) contralateral to that stimulated during a movement. Eighteen healthy subjects underwent a baseline PET scan followed, in randomized order, by a session of Real/Sham low‐frequency (1 Hz) subthreshold rTMS over the right M1 for 23 min. The site of stimulation was fMRI‐guided. After each rTMS session (real or sham), subjects underwent behavioral hand motor tests and four PET scans. During the first two scans, ten subjects (RH group) moved the right hand ipsilateral to the stimulated site and eight subjects (LH group) moved the left contralateral hand. All remained still during the last two scans (rest). Two stroke patients underwent the same protocol with rTMS applied on contralesional M1. Compared with Sham‐rTMS, Real‐rTMS over the right M1 was followed by a significant increase of rCBF during right hand movement in left S1M1, without any significant change in motor performance. The effect lasted less than 1 h. The same rTMS‐induced S1M1 overactivation was observed in the two stroke patients. Commissural connectivity between right dorsal premotor cortex and left M1 after real‐rTMS was observed with a psychophysiological interaction analysis in healthy subjects. No major changes were found for the left hand. These results give further arguments in favor of a plastic commissural connectivity between M1 both in healthy subjects and in stroke patients, and reinforce the potential for therapeutic benefit of low‐frequency rTMS in stroke rehabilitation. Hum Brain Mapp, 2009. © 2008 Wiley‐Liss, Inc.
Two systems of resting state connectivity between the insula and cingulate cortex
Authors: Taylor Keri S. , Seminowicz David A. , Davis Karen D. 
Published: December 2008

AbstractThe insula and cingulate cortices are implicated in emotional, homeostatic/allostatic, sensorimotor, and cognitive functions. Non‐human primates have specific anatomical connections between sub‐divisions of the insula and cingulate. Specifically, the anterior insula projects to the pregenual anterior cingulate cortex (pACC) and the anterior and posterior mid‐cingulate cortex (aMCC and pMCC); the mid‐posterior insula only projects to the posterior MCC (pMCC). In humans, functional neuroimaging studies implicate the anterior insula and pre/subgenual ACC in emotional processes, the mid‐posterior insula with awareness and interoception, and the MCC with environmental monitoring, response selection, and skeletomotor body orientation. Here, we tested the hypothesis that distinct resting state functional connectivity could be identified between (1) the anterior insula and pACC/aMCC; and (2) the entire insula (anterior, middle, and posterior insula) and the pMCC. Functional connectivity was assessed from resting state fMRI scans in 19 healthy volunteers using seed regions of interest in the anterior, middle, and posterior insula. Highly correlated, low‐frequency oscillations (< 0.05 Hz) were identified between specific insula and cingulate subdivisions. The anterior insula was shown to be functionally connected with the pACC/aMCC and the pMCC, while the mid/posterior insula was only connected with the pMCC. These data provide evidence for a resting state anterior insula–pACC/aMCC cingulate system that may integrate interoceptive information with emotional salience to form a subjective representation of the body; and another system that includes the entire insula and MCC, likely involved in environmental monitoring, response selection, and skeletomotor body orientation. Human Brain Mapp 2009. © 2008 Wiley‐Liss, Inc.
Intentional inhibition: How the “veto‐area” exerts control
Authors: Kühn Simone , Haggard Patrick , Brass Marcel 
Published: December 2008

AbstractOne important aspect of self‐control is refraining voluntarily from already planned behavior, by a final intervention before commitment to action. Despite its crucial role in human existence, and clear social implications, this aspect of self‐control has proved hard to study experimentally. One recent study used a perceptual timing paradigm to identify specific activations in the dorsal fronto‐median cortex (dFMC) associated with voluntary inhibition of action (Brass and Haggard 2007: J Neurosci 27:9141–9145). Here, we extend this work in two important new directions. First, we developed a more naturalistic task that gives participants a strong reason to inhibit or to execute actions, and therefore involves self‐control in the sense of voluntary inhibition of prepotent impulsive responses. Second, we investigated the relation between dFMC and other cognitive‐motor areas using effective connectivity analysis. We show that dFMC is activated when inhibiting prepared responses to external events. Moreover, its effective connectivity suggests that it allows intentional inhibition of action through top‐down inhibition of premotor areas. This view of dFMC is consistent with a new view of self‐control as a key stage in a cognitive‐motor interface. Hum Brain Mapp, 2009. © 2008 Wiley‐Liss, Inc.