bluuebunny/crossref_metadata_2025_split huggingface dataset:
Trimer Stabilization, Oligomerization, and Antibody-Mediated Cell Surface Immobilization Improve the Activity of Soluble Trimers of CD27L, CD40L, 41BBL, and Glucocorticoid-Induced TNF Receptor Ligand
Authors: Wyzgol Agnes , Müller Nicole , Fick Andrea , Munkel Sabine , Grigoleit Goetz Ulrich , Pfizenmaier Klaus , Wajant Harald 
Published: July 2009

Abstract
For many ligands of the TNF family, trimer stability and oligomerization status are crucial determinants of receptor activation. However, for the immunostimulatory ligands CD27L, CD40L, 41BBL, and glucocorticoid-induced TNF receptor ligand (GITRL) detailed information regarding these requirements is lacking. Here, we comprehensively evaluated the effect of trimer stability and oligomerization on receptor activation by these ligands. Treatment with soluble Flag-tagged CD27L, 41BBL, and GITRL minimally activated receptor signaling, while Flag-CD40L was highly active. Oligomerization with anti-Flag Abs further enhanced the specific activity of Flag-CD40L 10-fold and of Flag-41BBL more than 200-fold, but it failed to activate Flag-CD27L and Flag-GITRL. We next investigated the relevance of trimer stability by introducing the tenascin-C (TNC) trimerization domain, yielding stabilized Flag-TNC-ligand trimers. Oligomerization with anti-Flag Ab potently activated signaling by Flag-TNC-CD27L and Flag-TNC-GITRL and, albeit to a lesser extent, Flag-TNC-CD40L and Flag-TNC-41BBL. Forced hexamerization, by introducing an Ig Fc domain, revealed that hexameric derivatives of Flag-TNC-41BBL, Flag-CD40L, and Flag-TNC-GITRL all activate receptor signaling with high efficiency, whereas hexameric Flag-CD27L variant left inactive. Finally, we attempted to selectively activate receptor signaling on targeted cells, by using Ab fragment (single-chain fragment variable region, scFv)-ligand fusion proteins, an approach previously applied to other TNF ligands. Target cell surface Ag-selective activation was achieved for scFv-41BBL, scFv-CD40L, and scFv-GITRL, although the latter two displayed already significant activity toward Ag-negative cells. In conclusion, our data establish that trimeric CD40L is active, 41BBL requires hexamerization, GITRL requires trimer stabilization, and CD27L requires trimer stabilization and oligomerization. Furthermore, surface immobilization might be exploited to gain locally enhanced ligand activity.
IL-8 Regulates Mucin Gene Expression at the Posttranscriptional Level in Lung Epithelial Cells
Authors: Bautista Maria V. , Chen Yajun , Ivanova Vessela S. , Rahimi Michael K. , Watson Alan M. , Rose Mary C. 
Published: July 2009

Abstract
Airway inflammation and mucus hypersecretion/overproduction/obstruction are pathophysiological characteristics of cystic fibrosis, asthma, and chronic obstructive pulmonary disease. Up-regulation of airway mucin genes by inflammatory/immune response mediators is one of the major contributors to mucin overproduction. IL-8, a potent proinflammatory mediator and neutrophil chemoattractant, is present at high levels in the airway secretions of such patients. In this study, the effects of IL-8 on expression of two major airway mucin genes, MUC5AC and MUC5B, were evaluated. IL-8 increased the mRNA abundance of both mucin genes in two human respiratory tract-derived cell lines (A549 and NCI-H292) in a time- and concentration-dependent manner. IL-8 also increased MUC5AC and MUC5B mRNA levels in primary normal differentiated human bronchial epithelial cells, with a high concentration of IL-8 required to increase MUC5B mRNA levels. IL-8 did not transcriptionally up-regulate MUC5AC gene expression, but rather increased the stability of the MUC5AC transcript, suggesting regulation at the posttranscriptional level. In addition, IL-8 altered the levels of RNA-binding proteins to specific domains in the 3′-untranslated region of the MUC5AC transcript. Taken together, these data indicate that the IL-8-induced binding of RNA-binding proteins to the 3′-untranslated region of MUC5AC is a potential mechanism for regulating MUC5AC gene expression at the posttranscriptional level, thus suggesting a new role whereby IL-8 sustains mucin gene expression in inflamed airways.
Novel MHC Class I Structures on Exosomes
Authors: Lynch Sarah , Santos Susana G. , Campbell Elaine C. , Nimmo Ailish M. S. , Botting Catherine , Prescott Alan , Antoniou Antony N. , Powis Simon J. 
Published: July 2009

Abstract
Exosomes are nanometer-sized vesicles released by a number of cell types including those of the immune system, and often contain numerous immune recognition molecules including MHC molecules. We demonstrate in this study that exosomes can display a significant proportion of their MHC class I (MHC I) content in the form of disulfide-linked MHC I dimers. These MHC I dimers can be detected after release from various cell lines, human monocyte-derived dendritic cells, and can also be found in human plasma. Exosome-associated dimers exhibit novel characteristics which include 1) being composed of folded MHC I, as detected by conformational-dependent Abs, and 2) dimers forming between two different MHC I alleles. We show that dimer formation is mediated through cysteine residues located in the cytoplasmic tail domains of many MHC I molecules, and is associated with a low level of glutathione in exosomes when compared with whole cell lysates. We propose these exosomal MHC I dimers as novel structures for recognition by immune receptors.
Maternal Exposure to Secondhand Cigarette Smoke Primes the Lung for Induction of Phosphodiesterase-4D5 Isozyme and Exacerbated Th2 Responses: Rolipram Attenuates the Airway Hyperreactivity and Muscarinic Receptor Expression but Not Lung Inflammation and Atopy
Authors: Singh Shashi P. , Mishra Neerad C. , Rir-sima-ah Jules , Campen Mathew , Kurup Viswanath , Razani-Boroujerdi Seddigheh , Sopori Mohan L. 
Published: July 2009

AbstractAirway hyperreactivity (AHR), lung inflammation, and atopy are clinical signs of allergic asthma. Gestational exposure to cigarette smoke (CS) markedly increases the risk for childhood allergic asthma. Muscarinic receptors regulate airway smooth muscle tone, and asthmatics exhibit increased AHR to muscarinic agonists. We have previously reported that in a murine model of bronchopulmonary aspergillosis, maternal exposure to mainstream CS increases AHR after acute intratracheal administration of Aspergillus fumigatus extract. However, the mechanism by which gestational CS induces allergic asthma is unclear. We now show for the first time that, compared with controls, mice exposed prenatally to secondhand CS exhibit increased lung inflammation (predominant infiltration by eosinophils and polymorphs), atopy, and airway resistance, and produce proinflammatory cytokines (IL-4, IL-5, IL-6, and IL-13, but not IL-2 or IFN-γ). These changes, which occur only after an allergen (A. fumigatus extract) treatment, are correlated with marked up-regulated lung expression of M1, M2, and M3 muscarinic receptors and phosphodiesterase (PDE)4D5 isozyme. Interestingly, the PDE4-selective inhibitor rolipram attenuates the increase in AHR, muscarinic receptors, and PDE4D5, but fails to down-regulate lung inflammation, Th2 cytokines, or serum IgE levels. Thus, the fetus is extraordinarily sensitive to CS, inducing allergic asthma after postnatal exposure to allergens. Although the increased AHR might reflect increased PDE4D5 and muscarinic receptor expression, the mechanisms underlying atopy and lung inflammation are unrelated to the PDE4 activity. Thus, PDE4 inhibitors might ease AHR, but are unlikely to attenuate lung inflammation and atopy associated with childhood allergic asthma.
Crystal-Induced Neutrophil Activation: XI. Implication and Novel Roles of Classical Protein Kinase C
Authors: Popa-Nita Oana , Proulx Sophie , Paré Guillaume , Rollet-Labelle Emmanuelle , Naccache Paul H. 
Published: July 2009

Abstract
Monosodium urate (MSU) crystals are among the most potent proinflammatory stimuli, and an innate immune inflammatory response to the crystal surface is involved in the pathology of gouty arthritis. Furthermore, MSU crystals have recently been identified as danger signals able to induce the maturation of dendritic cells. Release of the crystals into the joint cavity promotes an acute inflammation characterized by a massive infiltration of neutrophils that leads to tissue damage. Protein kinase C (PKC) represents a family of serine/threonine kinases that play central signaling roles in multiple cellular responses. This family of kinases is divided into three subfamilies based on second messenger requirements: conventional (or classical), novel, and atypical. Despite their role in signal transduction, very little is known about the involvement of the PKC family in the inflammatory reaction induced by MSU crystals. In the present study, we show that MSU crystals activate conventional PKC isoforms, and that this activation is necessary for the MSU crystal-induced degranulation and generation of a chemotactic activity in the supernatants of MSU crystal-stimulated human neutrophils. Evidence is also obtained that the tyrosine kinase Syk is a substrate of PKC and that the PKC-mediated serine phosphorylation of Syk is necessary to its interaction with the regulatory subunit of PI3K kinases (p85) and thus to the subsequent activation of these lipid kinases. These results suggest novel means of modulating neutrophil responses (through the specific regulation of PKC) during the acute phase of MSU crystal-induced inflammation.
Cerebrospinal fluid of brain trauma patients inhibitsin vitroneuronal network function via NMDA receptors
Authors: Otto Frauke , Illes Sebastian , Opatz Jessica , Laryea Maurice , Theiss Stephan , Hartung Hans‐Peter , Schnitzler Alfons , Siebler Mario , Dihné Marcel 
Published: July 2009

AbstractNeurological diseases frequently induce pathological changes of cerebrospinal fluid (CSF) that might secondarily influence brain activity, as the CSF–brain barrier is partially permeable. However, functional effects of CSF on neuronal network activity have not been specified to date. Here, we report that CSF specimens from patients with reduced Glasgow Coma Scale values caused by severe traumatic brain injury suppress synchronous activity of in vitro‐generated neuronal networks in comparison with controls. We present evidence that underlying mechanisms include increasedN‐methyl‐D‐aspartate receptor activity mediated by a CSF fraction containing elevated amino acid concentrations. These proof‐of‐principle data suggest that determining effects of CSF specimens on neuronal network activity might be of diagnostic value. Ann Neurol 2009;66:546–555
Synthesis and Characterization of New Liver Targeting 5‐Fluorouracil‐Cholic Acid Conjugates
Authors: Qian Shan , Wu Jian‐Bo , Wu Xiao‐Chun , Li Jie , Wu Yong 
Published: July 2009

AbstractThe objective of this work was to develop a liver‐specific antihepato carcinoma agent. A series of 5‐fluorouracil / cholic acid conjugates (5‐FU‐cholic acid conjugates) were prepared and tested for their chemical characteristics and bio‐distribution properties. The in‐vitro stability trial showed 5‐FU‐cholic acid conjugates could be completely hydrolyzed by heating at 70°C in an acidic solution, pH = 1, for 5 min. The fast and complete hydrolysis of these compounds could be compatible with a fast separation and analysis method to shorten the analysis time. The decomposition speeds of the 5‐FU‐cholic acid conjugates in different organs of mice at several time points after oral administration were evaluated by measuring the concentrations of regenerated 5‐FU in organ tissue. The results were compared with those of the controls, which was a group of mice orally taking 5‐FU. The concentrations of 5‐FU in mice liver tissue were remarkably increased after oral administration of the prodrugs, and were much larger than if only orally administered 5‐FU. The results suggested the feasibility to improve therapeutic efficiency of liver targeting treatments by using cholic acid as the vector of drugs.
Rhenium‐ and Manganese‐Catalyzed Insertion of Alkynes into a Carbon–Carbon Single Bond of Cyclic and Acyclic 1,3‐Dicarbonyl Compounds
Authors: Kuninobu Yoichiro , Kawata Atsushi , Nishi Mitsumi , Yudha S. Salprima , Chen Jingjin , Takai Kazuhiko 
Published: July 2009

AbstractTreatment of alkynes with cyclic and acyclic 1,3‐dicarbonyl compounds in the presence of a catalytic amount of a rhenium or manganese complex gives ring‐expanded and carbon‐chain extension products, respectively. In these reactions, alkynes insert into a non‐strained carbon–carbon single bond of 1,3‐dicarbonyl compounds. The ring‐expansion reaction is also promoted by the addition of 4‐Å molecular sieves instead of a catalytic amount of an isocyanide.
Nanorobots: The Ultimate Wireless Self‐Propelled Sensing and Actuating Devices
Authors: Sánchez Samuel , Pumera Martin 
Published: July 2009

AbstractNatural motor proteins, “bionanorobots,” have inspired researchers to develop artificial nanomachines (nanorobots) able to move autonomously by the conversion of chemical to mechanical energy. Such artificial nanorobots are self‐propelled by the electrochemical decomposition of the fuel (up to now, hydrogen peroxide). Several approaches have been developed to provide nanorobots with some functionality, such as for controlling their movement, increasing their power output, or transporting different cargo. In this Focus Review we will discuss the recent advances in nanorobots based on metallic nanowires, which can sense, deliver, and actuate in complex environments, looking towards real applications in the not‐too‐distant future.
The four cysteines ring motif in proteins
Authors: Zagari Adriana 
Published: July 2009

AbstractDisulfide bonds play fundamental roles in proteins. This work is devoted to highly rare motifs containing disulfide bonds. A search for four cysteines, forming a 16‐atom membered ring (4CR) embodying two disulfide bonds, was carried out against all entries in the Protein Data Bank. Searching the crystallographic subset, only few protein molecules, all dimeric, were found to embody this peculiar structural feature, which establishes a covalent link between two different polypeptide chains. In contrast, in a peptide studied in solution by NMR, the four cysteines moiety includes only residues from one chain. A comparative analysis provided evidence for similarity and difference. It emerged that 4CR motif is highly rare and may serve to gain a specialized function. © 2009 Wiley Periodicals, Inc. Biopolymers 91: 1048–1055, 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
Design and validation of a pulsatile perfusion bioreactor for 3D high cell density cultures
Authors: Chouinard Julie A. , Gagnon Serge , Couture Marc G. , Lévesque Alain , Vermette Patrick 
Published: July 2009

AbstractThis study presents the design and validation of a pulsatile flow perfusion bioreactor able to provide a suitable environment for 3D high cell density cultures for tissue engineering applications. Our bioreactor system is mobile, does not require the use of traditional cell culture incubators and is easy to sterilize. It provides real‐time monitoring and stable control of pH, dissolved oxygen concentration, temperature, pressure, pulsation frequency, and flow rate. In this bioreactor system, cells are cultured in a gel within a chamber perfused by a culture medium fed by hollow fibers. Human umbilical vein endothelial cells (HUVEC) suspended in fibrin were found to be living, making connections and proliferating up to five to six times their initial seeding number after a 48‐h culture period. Cells were uniformly dispersed within the 14.40 mm × 17.46 mm × 6.35 mm chamber. Cells suspended in 6.35‐mm thick gels and cultured in a traditional CO2 incubator were found to be round and dead. In control experiments carried out in a traditional cell culture incubator, the scarcely found living cells were mostly on top of the gels, while cells cultured under perfusion bioreactor conditions were found to be alive and uniformly distributed across the gel. Biotechnol. Bioeng. 2009; 104: 1215–1223. © 2009 Wiley Periodicals, Inc.
Preparation of a super‐long two column chromatography system and its application in separating glycosylated puerarin
Authors: Zhu Shouchuang , Xu Haidong , Yu Cigang , Ding Juanfang , Chen Ting , Jiang Jierong , Dai Yijun , Liu Guiyou , Huang Guodong , Chai Nan , Jiang Xuhua , Yuan Sheng 
Published: July 2009

AbstractSeparation of Puerarin‐7‐O‐glucoside from its precursor, puerarin, using a common chromatography column packed with AB‐8 macroporous resin was unsuccessful. Therefore, in this study a 8 m super‐long flexible reinforced PVC column was externally added to the common column in order to improve the chromatography efficiency by increasing the number of theoretical plates. Both the PVC and common columns were separately packed with AB‐8 macroporous resin slurry. The packed PVC column was coiled after washing and stored until use. The microbial transformation mixture with puerarin‐7‐O‐glucoside and puerarin (250 mL) was loaded onto the common column, followed by washing with 2000 mL H2O. After attaching the coiled external PVC column to the common column, a linear gradient of 10–30% ethanol was applied to elute the target compound. Two peaks appeared: peak I contained puerarin‐7‐O‐glucoside at 97.9% purity and 88.1% recovery rate, and peak II was puerarin at 98.7% purity and 87.0% recovery rate. The use of the coiled external flexible reinforced PVC column avoided spatial restriction for long columns, which made it much more convenient for column packing and chromatography operations. Furthermore, this method eliminated the resin blockage problem caused by stationary water pressure in a rigid vertical long column. Using an external super‐long column, the PVC tube was connected with the common column only during elution, which avoided delay in time period during sample loading and column washes associated with the use of long external columns. Copyright © 2009 John Wiley & Sons, Ltd.
Fractionation of transgenic corn seed by dry and wet milling to recover recombinant collagen‐related proteins
Authors: Zhang Cheng , Glatz Charles E. , Fox Steven R. , Johnson Lawrence A. 
Published: July 2009

AbstractCorn continues to be considered an attractive transgenic host for producing recombinant therapeutic and industrial proteins because of its potential for producing recombinant proteins at large volume and low cost as coproducts of corn seed‐based biorefining. Efforts to reduce production costs have been primarily devoted to increasing accumulation level, optimizing protein extraction conditions, and simplifying the purification. In the present work, we evaluated two grain fractionation methods, dry milling and wet milling, to enrich two recombinant collagen‐related proteins; thereby, reducing the amount and type of corn‐derived impurities in subsequent protein extraction and purification steps. The two proteins were a full‐length human recombinant collagen type I alpha 1(rCIα1) chain with telopeptides and peptide foldon to effect triple helix formation and a 44‐kDa rCIα1 fragment. For each, ∼60% of the rCIα1s in the seed was recovered in the dry‐milled germ‐rich fractions making up ca. 25% of the total kernel mass. For wet milling, ∼60% of each was recovered in three fractions accounting for 20–25% of the total kernel mass. The rCIα1s in the dry‐milled germ‐rich fractions were enriched three to six times compared with the whole corn kernel, whereas the rCIα1s were enriched 4–10 times in selected wet‐milled fractions. The recovered starch from wet milling was almost free of rCIα1. Therefore, it was possible to generate rCIα1‐enriched fractions by both dry and wet milling along with rCIα1‐free starch using wet milling. Because of its simplicity, the dry milling procedure could be accomplished on‐farm thus minimizing the risk of inadvertent release of viable transgenic seeds. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009
Chain gear design using artificial neural networks
Authors: Toktas Ihsan , Basak Hudayim 
Published: July 2009

AbstractIn this study, the analytical calculation and analysis for the data corresponding to these gears have been made to obtain alternative test and training data sets to be used at the artificial neural networks(ANNs) with the constraints and requirements for the design of chain gears of power and motion transmission mechanisms are determined. In the input layer, the constraints and requirement values(input power, number of revolution of the pinion, number of revolution of the gear and center distance) of chain gears are used while at the output layer chain code(i.e., the chain gear type and chain sequence number), specifying the functional and physical properties, is used. Then the network is tested with the test data. The analytical calculation results and ANN predictions are compared by using statistical error analyzing methods such as absolute fraction of variance(R2), root mean square error(RMSE), and mean error percentage(MEP) for the training and test data. The chain code has been determined by the ANN with an acceptable accuracy. It is concluded that ANNs can be used as an alternative method in chain gear design. © 2009 Wiley Periodicals, Inc. Comput Appl Eng Educ 20: 38–44, 2012
Deactivation of TEM‐1 β‐Lactamase Investigated by Isothermal Batch and Non‐Isothermal Continuous Enzyme Membrane Reactor Methods
Authors: Rogers Thomas A. , Daniel Roy M. , Bommarius Andreas S. 
Published: July 2009

AbstractThe thermal deactivation of TEM‐1 β‐lactamase was examined using two experimental techniques: a series of isothermal batch assays and a single, continuous, non‐isothermal assay in an enzyme membrane reactor (EMR). The isothermal batch‐mode technique was coupled with the three‐state “Equilibrium Model” of enzyme deactivation, while the results of the EMR experiment were fitted to a four‐state “molten globule model”. The two methods both led to the conclusions that the thermal deactivation of TEM‐1 β‐lactamase does not follow the Lumry‐Eyring model and that the Teq of the enzyme (the point at which active and inactive states are present in equal amounts due to thermodynamic equilibrium) is at least 10 °C from the Tm (melting temperature), contrary to the idea that the true temperature optimum of a biocatalyst is necessarily close to the melting temperature.