bluuebunny/crossref_metadata_2025_split huggingface dataset:
NDRG1 is down‐regulated in the early apoptotic event induced by camptothecin analogs: The potential role in proteolytic activation of PKCδ and apoptosis
Authors: Zheng Ying , Wang Li‐Shun , Xia Li , Han Yu‐Hui , Liao Shi‐Hua , Wang Xiao‐Ling , Cheng Jin‐Ke , Chen Guo‐Qiang 
Published: March 2009

AbstractWe previously reported that NSC606985, a new camptothecin analog, induces apoptosis of acute myeloid leukemic cells, which is triggered by proteolytic activation of protein kinase C delta (PKCδ). Here, we performed quantitative proteomic analysis of NSC606985‐treated and untreated leukemic U937 cells with two‐dimensional fluorescence difference gel electrophoresis (2‐D DIGE) in combination with matrix‐assisted laser desorption/ionization time‐of‐flight/time‐of‐flight tandem mass spectrometry. Thirty‐three proteins were found to be deregulated. Then, we focused on N‐myc downstream regulated gene 1 (NDRG1) down‐regulated during apoptosis induction. The results demonstrated that the down‐regulation of NDRG1 protein but not its mRNA was an early event prior to proteolytic activation of PKCδ in U937 cells under treatments of NSC606985 as well as other camptothecin analogs. With the ectopic expression of NDRG1, the proteolytic activation of PKCδ in NSC606985‐treated leukemic cells was delayed and the cells were less sensitive to apoptosis. On the contrary, the suppression of NDRG1 expression by specific small interfering RNA significantly enhanced NSC606985‐induced activation of PKCδ and apoptosis of U937 cells. In summary, our study suggests that the down‐regulation of NDRG1 is involved in proteolytic activation of PKCδ during apoptosis induction, which would shed new light on the understanding the apoptotic process initiated by camptothecin.
Mapping of O‐linked β‐N‐acetylglucosamine modification sites in key contractile proteins of rat skeletal muscle
Authors: Hédou Julie , Bastide Bruno , Page Adeline , Michalski Jean‐Claude , Morelle Willy 
Published: March 2009

AbstractO‐linked β‐N‐acetylglucosamine (O‐GlcNAc) is a widespread modification of serine/threonine residues of nucleocytoplasmic proteins. Recently, several key contractile proteins in rat skeletal muscle (i.e., myosin heavy and light chains and actin) were identified as O‐GlcNAc modified. Moreover, it was demonstrated that O‐GlcNAc moieties involved in contractile protein interactions could modulate Ca2+ activation parameters of contraction. In order to better understand how O‐GlcNAc can modulate the contractile activity of muscle fibers, we decided to identify the sites of O‐GlcNAc modification in purified contractile protein homogenates. Using an MS‐based method that relies on mild β‐elimination followed by Michael addition of DTT (BEMAD), we determined the localization of one O‐GlcNAc site in the subdomain four of actin and four O‐GlcNAc sites in the light meromyosin region of myosin heavy chains (MHC). According to previous reports concerning the role of these regions, our data suggest that O‐GlcNAc sites might modulate the actin–tropomyosin interaction, and be involved in MHC polymerization or interactions between MHC and other contractile proteins. Thus, the results suggest that this PTM might be involved in protein–protein interactions but could also modulate the contractile properties of skeletal muscle.
Biomarker discovery in asthma‐related inflammation and remodeling
Authors: Calvo Florence Quesada , Fillet Marianne , de Seny Dominique , Meuwis Marie‐Alice , Maree Raphael , Crahay Céline , Paulissen Geneviève , Rocks Natacha , Gueders Maud , Wehenkel Louis , Merville Marie‐Paule , Louis Renaud , Foidart Jean‐Michel , Noël Agnes , Cataldo Didier 
Published: March 2009

AbstractAsthma is a complex inflammatory disease of airways. A network of reciprocal interactions between inflammatory cells, peptidic mediators, extracellular matrix components, and proteases is thought to be involved in the installation and maintenance of asthma‐related airway inflammation and remodeling. To date, new proteic mediators displaying significant activity in the pathophysiology of asthma are still to be unveiled. The main objective of this study was to uncover potential target proteins by using surface‐enhanced laser desorption/ionization‐time of flight‐mass spectrometry (SELDI‐TOF‐MS) on lung samples from mouse models of allergen‐induced airway inflammation and remodeling. In this model, we pointed out several protein or peptide peaks that were preferentially expressed in diseased mice as compared to controls. We report the identification of different five proteins: found inflammatory zone 1 or RELMα (FIZZ‐1), calcyclin (S100A6), clara cell secretory protein 10 (CC10), Ubiquitin, and Histone H4.
Towards functional proteomics of minority component of honeybee royal jelly: The effect of post‐translational modifications on the antimicrobial activity of apalbumin2
Authors: Bíliková Katarína , Mirgorodskaya Ekaterina , Bukovská Gabriela , Gobom Johan , Lehrach Hans , Šimúth Jozef 
Published: March 2009

AbstractThis study illustrates multifunctionality of proteins of honeybee royal jelly (RJ) and how their neofunctionalization result from various PTMs of maternal proteins. Major proteins of RJ, designated as apalbumins belong to a protein family consisting of nine members with Mr of 49–87 kDa and they are accompanied by high number of minority homologs derived from maternal apalbumins. In spite of many data on diversity of apalbumins, the molecular study of their individual minority homologous is still missing.This work is a contribution to functional proteomics of second most abundant protein of RJ apalbumin2 (Mr 52.7 kDa). We have purified a minority protein from RJ; named as apalbumin2a, differ from apalbumin2 in Mr (48.6 kDa), in N‐terminal amino acids sequences – ENSPRN and in N‐linked glycans. Characterization of apalbumin2a by LC‐MALDI TOF/TOF MS revealed that it is a minority homolog of the major basic royal jelly protein, apalbumin2, carrying two fully occupied N‐glycosylation sites, one with high‐mannose structure, HexNAc2Hex9, and another carrying complex type antennary structures, HexNAc4Hex3 and HexNAc5Hex4. We have found that apalbumin2a inhibit growth of Paenibacillus larvae. The obtained data call attention to functional plasticity of RJ proteins with potential impact on functional proteomics in medicine.
The seminal fluid proteome of the honeybee Apis mellifera
Authors: Baer Boris , Heazlewood Joshua L. , Taylor Nicolas L. , Eubel Holger , Millar A. Harvey 
Published: March 2009

AbstractEjaculates contain sperm but also seminal fluid, which is increasingly recognized to be of central importance for reproductive success. However, a detailed biochemical composition and physiological understanding of seminal fluid is still elusive. We have used MS to identify the 57 most abundant proteins within the ejaculated seminal fluid of the honeybee Apis mellifera. Their amino acid sequences revealed the presence of diverse functional categories of enzymes, regulators and structural proteins. A number have known or predicted roles in maintaining sperm viability, protecting sperm from microbial infections or interacting with the physiology of the female. A range of putative glycoproteins or glycosylation enzymes were detected among the 57, subsequent fluorescent staining of glycolysation revealed several prominant glycoproteins in seminal fluid, while no glycoproteins were detected in sperm samples. Many of the abundant proteins that accumulate in the seminal fluid did not contain predictable tags for secretion for the cell. Comparison of the honeybee seminal fluid proteins with Drosophila seminal fluid proteins (including secreted accessory gland proteins known as ACPs), and with the human seminal fluid proteome revealed the bee protein set contains a range of newly identified seminal fluid proteins and we noted more similarity of the bee protein set with the current human seminal fluid protein set than with the known Drosophila seminal fluid proteins. The honeybee seminal fluid proteome thus represents an important addition to available data for comparative studies of seminal fluid proteomes in insects.
Synthesis and characterization of L‐leucine containing chiral vinyl monomer and its polymer, poly(2‐(methacryloyloxyamino)‐4‐methyl pentanoic acid)
Authors: Bag Dibyendu S. , Dutta Dhiraj , Shami T. C. , Bhasker Rao K. U. 
Published: March 2009

AbstractA chiral monomer containing L‐leucine as a pendant group was synthesized from methacryloyl chloride and L‐leucine in presence of sodium hydroxide at 4 °C. The monomer was polymerized by free radical polymerization in propan‐2‐ol at 60 °C using 2,2′‐azobis isobutyronitrile (AIBN) as an initiator under nitrogen atmosphere. The polymer, poly(2‐(Methacryloyloxyamino)‐4‐methyl pentanoic acid) is thus obtained. The molecular weight of the polymer was determined to be: Mw is 6.9 × 103 and Mn is 5.6 × 103. The optical rotation of both chiral monomer and its polymer varies with the solvent polarity. The amplification of optical rotation due to transformation of monomer to polymer is associated with the ordered conformation of chiral monomer unit in the polymeric chain due to some secondary interactions like H‐bonding. The synthesized monomer and polymer exhibit intense Cotton effect at 220 nm. The conformation of the chain segments is sensitive to external stimuli, particularly the pH of the medium. In alkaline medium, the ordered chain conformation is destroyed resulting disordered random coils. The ordered coiling conformation is more firmly present on addition of HCl. The polymer exhibits swelling‐deswelling characteristics with the change of pH of the medium, which is reversible. The Cotton effect decreases linearly with the increase of temperature which is reversible on cooling. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2228–2242, 2009
Engineering polymer surfaces with variable chemistry and topography
Authors: Muñoz‐Bonilla Alexandra , Ibarboure Emmanuel , Papon Eric , Rodriguez‐Hernandez Juan 
Published: March 2009

AbstractWe describe the preparation of surfaces with controlled surface chemistry and topology combining both surface segregation of block copolymers and “breath figures” formation. For that purpose, an amphiphilic ABC triblock copolymer, that is, poly(2,3,4,5,6‐pentafluorostyrene)‐b‐polystyrene‐b‐poly[poly(ethylene glycol) methyl ether methacrylate] (PS5F21‐b‐PS31‐b‐PPEGMA38) was mixed with high molecular weight polystyrene and spin coated in a moist atmosphere. As demonstrated by X‐ray photoelectron spectroscopy and atomic force microscopy analysis, the surfaces exhibit spherical holes with diameters between 100 and 300 nm. The holes, enriched in triblock copolymer, exhibit variable chemical composition and topography depending on the environmental conditions. The surface functionality could be reversibly modulated: whereas under humid conditions the PPEGMA hydrophilic block reorients towards the surface, annealing to dry air directs the PS5F fluorinated block to the interface. Equally, surfaces annealed to humid air changed their topography from holes to islands depending on the extent of swelling of the PPEGMA block. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2262–2271, 2009
Ring‐opening polymerization of lactides initiated by magnesium and zinc complexes based on NNO‐tridentate ketiminate ligands: Activity and stereoselectivity studies
Authors: Huang Yong , Hung Wen‐Chou , Liao Ming‐Yuan , Tsai Tsung‐En , Peng Ya‐Liu , Lin Chu‐Chieh 
Published: March 2009

AbstractFour metal benzylalkoxides, [L2M2(μ‐OBn)2] (M = Mg or Zn), based on NNO‐tridentate ketiminate ligands are synthesized and characterized. X‐ray crystal structural studies of [(L1)2Mg2(μ‐OBn)2] (1a) and [(L1)2Zn2(μ‐OBn)2] (1b) (L1‐H = (Z)‐4‐((2‐(dimethylamino)ethylamino)(phenyl)methylene)‐3‐methyl‐1‐phenyl‐pyrazol‐5‐one) reveal that both complexes 1a and 1b are dinuclear species whereas the geometry around the metal center is penta‐coordinated bridging through the benzylalkoxy oxygen atoms in the solid structure. The activities and stereoselectivities of these four complexes toward the ring‐opening polymerization of L‐lactide and rac‐lactide are investigated. Polymerization of L‐lactide initiated by these four metal benzyloxides proceeds rapidly with good molecular weight control and yields polymer with a very narrow molecular weight distribution. The kinetic studies for the polymerization of L‐lactide with compound 1a show first order in both compound 1a and lactide concentrations with the polymerization rate constant, k, of 6.94 M/min. Besides, experimental results demonstrate that among these metal benzylalkoxides, complex 1a exhibits the highest stereoselectivity with a Pr up to 87% and complex 1b possesses the highest activity indicating that the terminal group of NNO‐tridentate ketimine ligands exerts a significant influence on both the reactivity and stereoselectivity of these complexes. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2318–2329, 2009
Three‐arm star ring opening metathesis polymers via alkyne‐azide click reaction
Authors: Dag Aydan , Durmaz Hakan , Sirkecioglu Okan , Hizal Gurkan , Tunca Umit 
Published: March 2009

AbstractThe click chemistry strategy is successfully applied for the preparation of three‐arm star (A3) ring opening metathesis polymers. A well‐defined monoazide end‐functionalized poly(N‐ethyl oxanorbornene) and a poly(N‐butyl oxanorbornene) obtained via ring opening metathesis polymerization using first generation Grubbs' catalyst are simply clicked with the trisalkyne core affording the synthesis of target star polymers. The obtained star polymers are characterized via nuclear magnetic resonance spectroscopy and gel permeation chromatography (GPC). The deconvolution analyses of GPC traces reveal that the click reaction efficiency for the star formation strongly depends on the chemical nature and the molecular weight of ROM polymers. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2344–2351, 2009
Modulated molecular recognition by a temperature‐sensitive molecularly‐imprinted polymer
Authors: Li Songjun , Pilla Srikanth , Gong Shaoqin 
Published: March 2009

AbstractModulated molecular recognition was achieved in a temperature‐sensitive molecularly‐imprinted polymer. Using PNIPA as the temperature‐sensitive element, the adenine‐imprinted polymer (i.e., MIP‐S) was prepared and characterized. The MIP‐S exhibited a temperature‐responsive molecular recognition behavior because of the thermal phase‐transition within the MIP‐S network. Specifically, below the transition temperature (e.g., 20 °C), the MIP‐S showed a highly specific recognition for the imprint species (adenine). However, the MIP‐S did not show any significant resolution for the imprint species (adenine) and its analogue (1‐methyladenine) above the transition temperature (e.g., 40 °C). Such temperature‐regulated recognition is comparable to a switch‐on and switch‐off process, thereby making tunable molecular recognition feasible. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2352–2360, 2009
Preparation and characterization of nematic polyazomethine/single‐walled carbon nanotube composites prepared by in situ polymerization
Authors: Lafuente Esperanza , Piñol Milagros , Martínez María Teresa , Muñoz Edgar , Oriol Luis , Serrano José Luis 
Published: March 2009

AbstractThe synthesis and characterization of a series of nematic SWNT‐polyazomethine composites are described. The composites were prepared by in situ polymerization in the presence of 1 wt % of chemically modified SWNTs in such a way that they were either dispersed or covalently bonded to the polymeric matrix. The presence of the SWNTs did not alter the thermal behavior of the polymer matrix and, therefore, highly oriented fibers could be melt‐extruded from the composites at moderate temperatures, as revealed by structural and morphological studies. Preliminary tests on tensile properties indicate that strength and stiffness were improved when compared with fibers without CNTs, particularly when SWNTs were covalently bonded to the polymeric matrix. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2361–2372, 2009
Monolithic biocompatible and biodegradable scaffolds for tissue engineering
Authors: Buchmeiser Michael R. 
Published: March 2009

AbstractThe state of the art in polymeric materials for tissue engineering as well as the needs and concerns for future medical applications are outlined and discussed and brought into relation to recent developments in polymer chemistry. Particularly, the recent developments in micro‐ and nano‐structured polymeric monoliths designed for these purposes will be discussed. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2219–2227, 2009
Linear polyurethanes made from naturally occurring tartaric acid
Authors: Marín Romina , Martínez de Ilarduya Antxon , Muñoz‐Guerra Sebastián 
Published: March 2009

AbstractNaturally occurring tartaric acid was used as raw material for the synthesis of novel linear polyurethanes (PURs) bearing two carboxylate side‐groups in the repeating unit. Aliphatic and aromatic PURs were obtained by reaction in solution of alkyl and benzyl tartrates with hexamethylene diisocyanate and 4,4′‐methylene‐bis(phenyl isocyanate), respectively. All the novel PURs were thermally stable and optically active. The aliphatic carboxylate‐containing PURs had Mw in the 40–70 kDa range, with PD between 2.1 and 2.5; all were semicrystalline polymers with melting temperatures between 100 and 150 °C and Tg in the 50–80 °C range. The aromatic PURs were amorphous materials with molecular weights between 18 kDa and 25 kDa and Tg above 130 °C. Hydrogenolysis of the PUR made from hexamethylene diisocyanate and benzyl tartrate yielded PURs containing up to 40% of free carboxylic side‐groups. The tartrate‐derived PURs displayed enhanced sensitivity to hydrolysis compared with their unsubstituted 2,6‐PUR homologs. The PURs bearing free carboxylic groups were unique in being degraded by water upon incubation under physiological conditions. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2391–2407, 2009
Synthesis and characterization of optically active helical vinyl polymers via free radical polymerization
Authors: Zhi Junge , Guan Yan , Cui Jiaxi , Liu Anhua , Zhu Zhiguo , Wan Xinhua , Zhou Qifeng 
Published: March 2009

AbstractA facile synthetic route to prepare the dual‐functional molecule, 2,5‐bis(4′‐carboxyphenyl)styrene, was developed. The esterification of this compound with chiral alcohols, that is, (S)‐(+)‐sec‐butanol/(R)‐(−)‐sec‐butanol, (S)‐(+)‐sec‐octanol/(R)‐(−)‐sec‐octanol, and D‐(+)‐menthol/L‐(−)‐menthol, respectively, yielded three enantiomeric pairs of novel vinyl monomers, which underwent radical polymerization to obtain helical polymers with an excess screw sense. These polymers exhibited optical rotations as large as fourfold those of the corresponding monomers. Their helical conformations were quite stable as revealed by the almost unchanged chiroptical properties measured at different temperatures. The polymers with linear alkyl tails in the side‐groups formed irreversibly columnar nematic phases in melt although the corresponding monomers were not liquid crystalline. Whereas, the polymers with cyclic tails generated no mesophase. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2408–2421, 2009
Synthesis and characterization of photocrosslinked poly(ε‐caprolactone)s showing shape‐memory properties
Authors: Nagata Minoru , Yamamoto Yu 
Published: March 2009

AbstractPoly(ε‐caprolactone) (PCL) with a pendent coumarin group was prepared by solution polycondensation from 7‐(3,5‐dicarboxyphenyl) carbonylmethoxycoumarin dichloride and α, ω‐dihydroxy terminated poly(ε‐caprolactone) with molecular weights of 1250, 3000, and 10,000 g/mol. These photosensitive polymers underwent a rapid reversible photocrosslinking upon exposure to irradiation with alternating wavelengths (>280/254 nm) without a photoinitiator. The thermal and mechanical properties of the photocrosslinked films were examined by means of differential scanning calorimetry and stress–strain measurements. The crosslinked films exhibited elastic properties above the melting temperature of the PCL segment along with significant decrease in the ultimate tensile strength and Young's modulus. Shape‐memory properties such as strain fixity ratio (Rf) and strain recovery ratio (Rr) were determined by means of a cyclic thermomechanical tensile experiments under varying maximum strains (εm = 100, 300, and 500%). The crosslinked ICM/PCL‐3000 and ‐10,000 films exhibited the excellent shape‐memory properties in which both Rf and Rr values were 88–100% for tensile strain of 100–500%; after the deformation, the films recovered their permanent shapes instantaneously. In vitro degradation was performed in a phosphate buffer saline (pH 7.2) at 37 °C with or without the presence of Pseudomonas cepacia lipase. The presence of the pendent coumarin group and the crosslinking of the polymers pronouncedly decreased the degradation rate. The crosslinked biodegradable PCL showing a good shape‐memory property is promising as a new material for biomedical applications. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2422–2433, 2009
Synthesis and spectroscopic investigation of π‐conjugated (E)‐enyne polycarbazole with different organo‐metallic catalysts from 3,6‐diethynyl‐9‐(2‐ethylhexyl)carbazole
Authors: Moon In Kyu , Kawamoto Masuki , Wada Tatsuo 
Published: March 2009

AbstractIn the present study, a new (E)‐rich‐enyne π‐conjugated polymer containing a carbazole was designed and synthesized. Two different synthesis methods of poly[N‐(2‐ethylhexyl)‐3,6‐carbazolyleneethynylene‐(E)‐vinylene] (PCZEV) have been prepared from 3,6‐diethynyl‐9(2‐ethylhexyl)carbazole by using the palladium‐carbene‐catalyzed reaction and/or by using the organolanthanide‐catalyzed reaction leading to well‐defined polymer, and their general properties were studied. Compared to poly[N‐(2‐ethylhexyl)‐3,6‐carbazolyleneethynylene] (PCE), the UV‐vis absorption and photoluminescence of the PCZEV was red‐shifted, which indicates the extension of conjugation length. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2434–2442, 2009
Poly(arylene sulfide)s by nucleophilic aromatic substitution polymerization of 2,7‐difluorothianthrene
Authors: Robb Maxwell J. , Knauss Daniel M. 
Published: March 2009

AbstractPoly(thianthrene phenylene sulfide) and poly(thianthrene sulfide) have been prepared by nucleophilic aromatic substitution polymerization of the activated monomer 2,7‐difluorothianthrene with bis thiophenoxide and sulfide nucleophiles, respectively. The resulting polymers are thermally stable, amorphous materials that have been characterized by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), gel permeation chromatography (GPC), matrix‐assisted laser desorption/ionization‐time‐of‐flight (MALDI‐TOF) mass spectrometry, UV‐Vis spectroscopy, refractometry, and intrinsic viscosity (IV) measurements. The polymers produced exhibit 5% weight loss values approaching 500 °C in inert and air atmospheres and glass transition temperatures that range from 149 to 210 °C. Poly(thianthrene phenylene sulfide) with a number average molecular weight of 22,100 g/mol has been synthesized with an IV in DMPU of 0.62 dL/g at 30 °C. Creasable films of this polymer have been prepared by solvent casting and melt pressing at 250 °C. Films of poly(thianthrene phenylene sulfide) exhibit transparencies greater than 50% at wavelengths exceeding 400 nm and a high refractive index value of 1.692 at a wavelength of 633 nm, making the polymer interesting for optical applications. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2453–2461, 2009