bluuebunny/crossref_metadata_2025_split huggingface dataset:
Phosphorylation of mitochondrial phospholipid scramblase 3 by protein kinase C‐δ induces its activation and facilitates mitochondrial targeting of tBid
Authors: He Yongwen , Liu Jihua , Grossman Douglas , Durrant David , Sweatman Trevor , Lothstein Leonard , Epand Raquel F. , Epand Richard M. , Lee Ray M. 
Published: January 2007

AbstractPhospholipid scramblase 3 (PLS3) is a member of the phospholipid scramblase family present in mitochondria. PLS3 plays an important role in regulation of mitochondrial morphology, respiratory function, and apoptotic responses. PLS3 is phosphorylated by PKC‐δ at Thr21 and is the mitochondrial target of PKC‐δ‐induced apoptosis. Cells with overexpression of PLS3, but not the phosphoinhibitory mutant PLS3(T21A), are more susceptible to apoptosis induced by AD198, an extranuclear targeted anthracycline that activates PKC‐δ. Here we report that the phosphomimetic mutant of PLS3(T21D) by itself can induce apoptosis in HeLa cells. Using proteoliposomes with addition of pyrene‐labeled phosphatidylcholine (PC) at the outer leaflet, we measured the lipid flip‐flop activity of PLS3 and its phosphorylation mutant. PLS3(T21D) is more potent than wild‐type PLS3 or PLS3(T21A) to transfer pyrene‐PC from the outer leaflet to the inner leaflet of liposomes. Based on our previous finding that PLS3 enhances tBid‐induced mitochondrial damages, we tested the hypothesis that PLS3 enhances cardiolipin translocation to mitochondrial surface and facilitates tBid targeting. Fluorescein‐labeled tBid(G94E) was used as a probe to quantify cardiolipin on the surface of mitochondria. Mitochondria from cells treated with AD198 or cells expressing PLS3(T21D) had a higher level of tBid‐binding capacity than control cells or cells expressing wild‐type PLS3. These findings indicate that phosphorylation of PLS3 by PKC‐δ induces PLS3 activation to facilitate mitochondrial targeting of tBid and apoptosis. J. Cell. Biochem. 101:1210–1221, 2007. © 2007 Wiley‐Liss, Inc.
Oncostatin M promotes osteogenesis and suppresses adipogenic differentiation of human adipose tissue‐derived mesenchymal stem cells
Authors: Song Hae Young , Jeon Eun Su , Kim Jung Il , Jung Jin Sup , Kim Jae Ho 
Published: January 2007

AbstractOncostatin M (OSM) is a multifunctional cytokine of the interleukin‐6 family and has been implicated in embryonic development, differentiation, inflammation, and regeneration of liver and bone. In the present study, we demonstrated that treatment of human adipose mesenchymal stem cells (hADSCs) with OSM‐attenuated adipogenic differentiation, as indicated by decreased accumulation of intracellular lipid droplets and down‐regulated expression of adipocytic markers, such as lipoprotein lipase and PPARγ. However, OSM treatment stimulated osteogenic differentiation, as demonstrated by the increase in matrix mineralization and expression levels of osteogenic differentiation markers, including alkaline phosphatase, Runx2, and osteocalcin. OSM treatment induced activation of JAK2, JAK3, and ERK in hADSCs, and pre‐treatment of hADSCs with the JAK2 inhibitor, AG490, significantly restored the OSM‐induced inhibition of adipogenic differentiation. Whereas, the JAK3 inhibitor, WHI‐P131, and the MEK inhibitor, U0126, had no effects on the anti‐adipogenic activity of OSM. On the other hand, the pro‐osteogenic activity of OSM was prevented by treatment of the cells with WHI‐P131 or U0126, but not with AG490. These results indicate that distinct signaling pathways, including JAK2, JAK3, and MEK‐ERK, play specific roles in the OSM‐induced anti‐adipogenic and pro‐osteogenic differentiation of hADSCs. J. Cell. Biochem. 101:1238–1251, 2007. © 2007 Wiley‐Liss, Inc.
Concerted activation of the Mdm2 promoter by p72 RNA helicase and the coactivators p300 and P/CAF
Authors: Shin Sook , Janknecht Ralf 
Published: January 2007

AbstractA scarcely studied and under‐recognized feature of RNA helicases is their ability to regulate gene transcription. In particular, very little is known about the role of p72 RNA helicase in gene regulation. Here, we have analyzed how this helicase may enhance promoter activity. We demonstrate that p72 RNA helicase forms complexes with the homologous coactivators p300 and CBP in vitro and in vivo, especially leading to an enhancement of the transactivation potential of their C‐termini. In addition, we show that the p300/CBP‐associated protein (P/CAF) also interacts with p72 RNA helicase, and both this interaction and the binding to p300/CBP are mediated by the N‐terminal 63 amino acids of p72 RNA helicase. p300, P/CAF and p72 RNA helicase synergize to stimulate selected promoters, including the Mdm2 one. Notably, downregulation of p72 RNA helicase leads to reduced Mdm2 transcription. Furthermore, our data suggest that p72 RNA helicase activates the Mdm2 promoter in a p53 dependent and independent manner. Collectively, our results have unraveled a mechanism of how p72 RNA helicase can regulate gene transcription, namely by cooperating with p300/CBP and P/CAF. Thereby, p72 RNA helicase may not only be involved in the p53‐Mdm2 regulatory loop, but also profoundly impact on the transcriptome through various CBP/p300 and P/CAF interacting proteins. J. Cell. Biochem. 101:1252–1265, 2007. © 2007 Wiley‐Liss, Inc.
Heparin suppresses lipid raft‐mediated signaling and ligand‐independent EGF receptor activation
Authors: Liu Yuan‐Tao , Song LiFang , Templeton Douglas M. 
Published: January 2007

AbstractHeparin is well known to suppress vascular smooth muscle cell (VSMC) proliferation, and attempts to exploit this therapeutically have led to recognition of multiple pathways for heparin's anti‐mitogenic actions. At low concentrations (ca. 1 µg · ml−1), these suppressive effects may reflect physiological activities of endogenous heparan sulfates, and appear to be rapid responses to extracellular or cell surface‐associated heparin. Because heparin has been shown to influence expression of caveolin proteins, and caveolae/lipid rafts are critical structures modulating cell signaling, we examined the effect of heparin on signaling involving cholesterol‐rich membrane microdomains. The VSMC line PAC‐1 activates the MAP kinase Erk in response to the cholesterol‐sequestering agents methyl‐β‐cyclodextrin and nystatin. This follows a temporal sequence that involves Ras‐GTP activation of MEK, and is independent of PKC, Src, and PI3 kinase. However, ligand‐independent phosphorylation of the EGF receptor (EGFR) by removal of cholesterol precedes Ras activation, and the EGFR kinase inhibitor AG1478 blocks Erk phosphorylation, supporting occurrence of the signaling sequence EGFR‐Ras‐MEK‐Erk. Phosphorylation of EGFR occurs predominantly in caveolin‐rich microdomains as identified by Western blotting of fractions from density gradient centrifugation of membranes prepared under detergent‐free conditions. In these situations, heparin inhibits phosphorylation of EGFR on the Src‐dependent site Tyr845, but not the autophosphorylation of Tyr1173, and decreases Ras activation and Erk phosphorylation. We conclude that heparin can suppress Erk signaling in VSMC with effects on site‐specific phosphorylation of EGFR localized in caveolin‐enriched lipid rafts. J. Cell. Physiol. 211: 205–212, 2007. © 2007 Wiley‐Liss, Inc.
Dual transcriptional control of claudin‐11 via an overlapping GATA/NF‐Y motif: Positive regulation through the interaction of GATA, NF‐YA, and CREB and negative regulation through the interaction of Smad, HDAC1, and mSin3A
Authors: Lui Wing‐Yee , Wong Elissa W.P. , Guan Yuanfang , Lee Will M. 
Published: January 2007

AbstractThe expression of claudin‐11, a key integral tight junction protein, is tightly regulated to ensure that the integrity of the seminiferous epithelium could be maintained during the translocation of spermatocytes at the blood–testis barrier at stages VIII–IX. In this study, we elucidate how the overlapping GATA/NF‐Y motif within the core promoter of claudin‐11 gene is modulated by differential binding of various transcription factors, resulting in dual transcriptional control. Using electrophoretic mobility shift assay (EMSA) and chromatin immunoprecipitation (ChIP) assay, we confirmed that GATA, nuclear factor YA (NF‐YA), and cAMP response element‐binding protein (CREB) form a complex in vivo and bind to the GATA/NF‐Y region to promote claudin‐11 gene transcription. Such gene activations were significantly reduced in the presence of siRNA specific to these transcription factors. GATA and CREB transactivation could be further modulated by the presence of Smad3 and Smad4 proteins. Binding of Smad proteins at the GATA/NF‐Y motif could repress the GATA and CREB transactivation of claudin‐11 gene. Such repression which required the recruitment and physical interactions of histone deacetylase 1 and its co‐repressor, mSin3A with Smad proteins, was abolished by treatment with Trichostatin A, thus suggesting the involvement of histone deacetylation at the site of the promoter region. It is believed that cyclic changes in the ratio of positive regulators (GATA, NF‐Y, and CREB) to negative regulators (Smads) in the seminiferous epithelium during the spermatogenic cycle might provide a precise control in claudin‐11 gene transcription. J. Cell. Physiol. 211: 638–648, 2007. © 2007 Wiley‐Liss, Inc.
Evaluation of the viability of cultured corneal endothelial cells by quantitative electron probe X‐ray microanalysis
Authors: Alaminos M. , Sanchez‐Quevedo M.C. , Muñoz‐Ávila J.I. , García J.M. , Crespo P.V. , González‐Andrades M. , Campos A. 
Published: January 2007

AbstractConstruction of artificial organs and tissues by tissue engineering is strongly dependent on the availability of viable cells. For that reason, the viability and the physiological status of cells kept in culture must be evaluated before the cells can be used for clinical purposes. In this work, we determined the viability of isolated rabbit corneal endothelial cells by trypan blue staining and quantitative electron probe X‐ray microanalysis. Our results showed that the ionic content of potassium in cultured corneal endothelial cells tended to rise initially, but significantly decreased in cells in the fifth (and final) subculture, especially in comparison to cells in the fourth subculture (P < 0.001). However, the concentration of sulfur was higher in the fifth subculture than in the fourth subculture (P < 0.001), with a nonsignificant increase in sodium in the fifth subculture (P = 0.031). These data imply a remarkable decrease in the K/Na ratio from the fourth to the fifth subculture. Our microanalytical results, along with the morphological differences between cells in the last two subcultures, are compatible with an early phase of the preapoptotic process in the fifth subculture, and suggest that cells of the first four subcultures would be better candidates for tissue engineering. J. Cell. Physiol. 211: 692–698, 2007. © 2007 Wiley‐Liss, Inc.
The small‐scale manufacturing sector in Ghana: a source of dynamism or of subsistence income?
Authors: Mensah John Victor , Tribe Michael , Weiss John 
Published: January 2007

AbstractSurvey data from small‐scale manufacturing enterprises in Central Region, Ghana permit analysis of factors affecting performance, and of economic dynamism. The majority of the firms were sole proprietorships, with most of the hired labour being apprentices. A high proportion of rural‐based proprietors and many urban‐based proprietors had secondary occupations. All but two of the industry groups were unprofitable when the legal minimum wage was used as a proxy for the value of proprietors' time. The implication of this is that the small‐scale industries are principally a source of modest income and may not be financially and economically dynamic. However, the small enterprises surveyed do seem to represent part of a ‘sustainable livelihoods’ strategy of lowering economic risk by diversifying income sources. Copyright © 2007 John Wiley & Sons, Ltd.
Designer Self‐Assembling Peptide Materials
Authors: Zhao Xiaojun , Zhang Shuguang 
Published: January 2007

AbstractUnderstanding of macromolecular materials at the molecular level is becoming increasingly important for a new generation of nanomaterials for nanobiotechnology and other disciplines, namely, the design, synthesis, and fabrication of nanodevices at the molecular scale from bottom up. Basic engineering principles for microfabrication can be learned through fully grasping the molecular self‐assembly and programmed assembly phenomena. Self‐ and programmed‐assembly phenomena are ubiquitous in nature. Two key elements in molecular macrobiological material productions are chemical complementarity and structural compatibility, both of which require weak and non‐covalent interactions that bring building blocks together during self‐assembly. Significant advances have been made during the 1990s at the interface of materials chemistry and biology. They include the design of helical ribbons, peptide nanofiber scaffolds for three‐dimensional cell cultures and tissue engineering, peptide surfactants for solubilizing and stabilizing diverse types of membrane proteins and their complexes, and molecular ink peptides for arbitrary printing and coating surfaces as well as coiled‐coil helical peptides for multi‐length scale fractal structures. These designer self‐assembling peptides have far reaching implications in a broad spectrum of applications in biology, medicine, nanobiotechnology, and nanobiomedical technology, some of which are beyond our current imaginations.magnified image
Water‐Triggered Frontal Polymerization
Authors: Pujari Narahari S. , Inamdar Satish R. , Ponrathnam Surendra , Kulkarni Bhaskar D. 
Published: January 2007

AbstractA totally new mode of frontal polymerization (FP) of acrylamide is established which is triggered by the simple addition of a minute, specific volume of water. Experimental conditions under which this mode of polymerization yields linear and water‐soluble polyacrylamide were carefully established, paving the way to synthesize commercially pertinent homo‐ and copolymers. A new redox couple was identified to circumvent the imidization and the ensuing gelation, hitherto associated with FP of acrylamide. Effects of reaction variables such as type and concentration of redox couple and volume of water on measurable parameters of FP such as front velocity, front temperature, shape of front and yield have been studied. Two types of redox couples are reported. Nonplanar frontal regime was observed in few redox couples. We could visually observe helical patterns with naked eyes, while layered patterns were observable under SEM. Additionally, micro‐phase separation and heterogeneity in the polymer matrix was observed due to unreacted pockets of monomer which evolve via bulk mode. This nonlinear phenomenon is described.magnified image
Epoxy/Silica Nanocomposites: Nanoparticle‐Induced Cure Kinetics and Microstructure
Authors: Rosso Patrick , Ye Lin 
Published: January 2007

AbstractThis study reveals the influence of silica nanoparticles on the cure reactions of a diglycidyl ether of bisphenol A epoxy resin. As soon as the silica nanoparticles are added to the neat resin (1, 3, and 5 vol.‐%), the total degree of conversion increases with an increasing amount of nanoparticles, and the cure reaction shows a more complex autocatalytic behaviour, which can not be described by a traditional kinetic model. Results from subsequent thermo‐mechanical analyses confirm an alteration in the microstructure attributable only to the presence of the nanoparticles in the curing stage. An amino‐rich interphase around the reactive treated particles is formed, which shifts the resin/hardener ratio, and benefits the homopolymerization of the epoxy and leads to a more highly crosslinked epoxy network. At the same time, the nanophase consists of a core‐shell structure with the rigid particle inside and a rubber‐like shell because of the excess hardener in this region.TEM image of two neighboring silica nanoparticles in the epoxy matrix showing a 2–3 nm altered interphase region.magnified imageTEM image of two neighboring silica nanoparticles in the epoxy matrix showing a 2–3 nm altered interphase region.
A New Type of Macroscopically Oriented Smectic‐A Liquid Crystal Elastomer
Authors: Komp Ansgar , Finkelmann Heino 
Published: January 2007

AbstractSmectic‐A liquid single crystal elastomers (SA‐LSCE) are materials where the rubber elasticity of the polymer network is combined with the one‐dimensional positional long‐range order of mesogenic groups which are covalently attached to the network. In the systems investigated so far, a mechanical deformation of the network causes significant reorientation processes of the layered structure. We present a new type of SA‐LSCE in which this structure remains unaffected on mechanical deformation both parallel and perpendicular to the director. The thermoelastic behavior, macroscopic dimensions, and stress–strain measurements parallel as well as perpendicular to the director are investigated. X‐ray studies confirm that a deformation parallel and perpendicular to the layer normal does not alter the macroscopically ordered lamellar structure with respect to the order parameter and the layer correlation length. We propose a simple picture where defects within the lamellar structure might account for these findings.magnified image
Swelling and Dissolution of Cellulose Part II: Free Floating Cotton and Wood Fibres in NaOH–Water–Additives Systems
Authors: Cuissinat Celine , Navard Patrick 
Published: January 2007

AbstractSummary: The swelling and dissolution mechanisms of native cotton and wood cellulose fibres in NaOH–water are studied. The cellulose fibres exhibit a heterogeneous swelling by ballooning in the best dissolving conditions (−5 °C, 7.6% of NaOH). This corresponds to the mode 3 of the swelling‐dissolution (see companion paper). In this region of the mixture phase diagram, cellulose is only dissolved inside the balloons. A lot of insoluble parts are present. Increasing the temperature and/or the content of NaOH decreases the quality of the solvent. In this case, the cellulose fibres do not show ballooning, but only a homogeneous swelling (mode 4). Three components are tested as additives: urea, zinc oxide and N‐methylmorpholine– N–oxide (NMMO). The swelling and dissolution mechanisms in NaOH‐water and NaOH–water–additives stay the same. Adding urea to NaOH‐water (−5 °C, 7.6% of NaOH) gives the same ballooning mechanisms, but with a larger expansion of the balloons, indicating that the solvent is better. Zinc oxide does not increase the expansion of the balloons, but the kinetics of swelling is faster. NMMO acts as a dissolution inhibitor.
Regioselectively Functionalized Cellulose Derivatives: A Mini Review
Authors: Koschella Andreas , Fenn Dominik , Illy Nicolas , Heinze Thomas 
Published: January 2007

AbstractSummary: The paper reviews recent developments in synthesis and characterization of regioselectively functionalized cellulose derivatives. It demonstrates the importance of protecting groups like triphenylmethyl‐ and thexyldimethylsilyl (TDMS) ethers in cellulose chemistry. The protected cellulose derivatives can be used for the preparation of 2,3‐O‐functionalized polymers. Moreover, the TDMS group opens up the synthesis of 3‐O‐ethers of cellulose that possess interesting properties in terms of structure in solution, water‐solubility, and thermoreversible gelation.
A New Kinetic Model for Water Sorption Isotherms of Cellulosic Materials
Authors: Kohler Robert , Alex Rainer , Brielmann Renate , Ausperger Bernhard 
Published: January 2007

AbstractSummary: Some natural fibres like flax, hemp and others show excellent mechanical properties which make them a promising choice for the reinforcement of polymers. For natural fibre reinforced composites, hydrophilicity is a problem with respect to dimensional changes, fibre to matrix adhesion and long term stability. The interaction of differently prepared and modified fibres with water vapour has been investigated by dynamic vapour sorption. It has been found that the sorption and desorption kinetics of cellulosic fibres can be excellently fitted by assuming two parallel, independent first order processes. This empirical model, defined here as the “Parallel Exponential Kinetics” model (PEK‐model), reveals two distinct mechanisms with slow and fast exchange of water vapour respectively, related to different sorption sites. The specific sorption mechanisms are represented by individual sorption‐desorption isotherms as components of the total isotherms. The results suggest a relation to the differing types of amorphous regions in the fibres and/or to the different states of “bound” or “free” water, discussed for hydrophilic materials. The PEK‐model proved to be consistently applicable for sorption and desorption over the whole humidity range, and also for all tested cellulose fibres. It is especially useful for a clearer distinction of different fibre types or modifications and can be successfully used for an extended fibre characterization.
Novel Thermoplastic Composites from Commodity Polymers and Man‐Made Cellulose Fibers
Authors: Fink Hans‐Peter , Ganster Johannes 
Published: January 2007

AbstractSummary: A new class of fibre reinforced commodity thermoplastics suited for injection moulding and direct processing applications has been developed using man‐made cellulosic fibres (Rayon tire yarn, Tencel, Viscose, Carbacell) and thermoplastic commodity polymers, such as polypropylene (PP), polyethylene (PE), high impact polystyrene (HIPS), poly(lactic acid) (PLA), and a thermoplastic elastomer (TPE) as the matrix polymer. For compounding, a specially adapted double pultrusion technique has been employed which provides composites with homogeneously distributed fibres. Extensive investigations were performed with Rayon reinforced PP in view of applications in the automotive industry. The Rayon‐PP composite is characterized by high strength and an excellent impact behaviour as compared with glass fibre reinforced PP, thus permitting applications in the field of engineering thermoplastics such as polycarbonate/acrylonitrile butadiene styrene blends (PC/ABS). With the PP based composites the influence of material parameters (e.g. fibre type and load, coupling agent) were studied and it has been demonstrated how to tailor the desired composite properties as modulus and heat distortion temperature (HDT) by varying the fibre type or adding inorganic fillers. Man‐made cellulose fibers are also suitable for the reinforcement of further thermoplastic commodity polymers with appropriate processing temperatures. In case of PE modulus and strength are tripled compared to the neat resin while Charpy impact strength is increased five‐fold. For HIPS mainly strength and stiffness are increased, while for TPE the property profile is changed completely. With Rayon reinforced PLA, a fully biogenic and biodegradable composite with excellent mechanical properties including highly improved impact strength is presented.
Aerocellulose: Aerogels and Aerogel‐like Materials made from Cellulose
Authors: Innerlohinger Josef , Weber Hedda K. , Kraft Gregor 
Published: January 2007

AbstractSummary: Cellulose aerogels have been prepared starting from cellulose‐NMMO solutions via the classical aerogel‐path. Different cellulosic materials have been tested and their influence on the properties of the product aerogels has been studied. Other parameters that have been varied include solution composition as well as the way of cellulose regeneration (solvent and temperature). More than 300 different samples were prepared and analysed. Their density is in a typical range from 0.02 g/cm3 to 0.2 g/cm3 and their internal surface area ranges from 100 m2/g to 400 m2/g. Another property investigated in detail beside density and internal surface area was the shrinkage of the cellulosic bodies during the production process.