bluuebunny/crossref_metadata_2025_split huggingface dataset:
A protein network for phospholipid synthesis uncovered by a variant of the tandem affinity purification method in Escherichia coli
Authors: Gully Djamel , Bouveret Emmanuelle 
Published: November 2005

AbstractIn prokaryotes, acyl carrier protein (ACP) is a cofactor central to a myriad of syntheses, including fatty acid and phospholipid synthesis. To fulfill its function, ACP must therefore interact with a multitude of different enzymes, which includes the thioesterase YbgC. We found a specific interaction between ACP and YbgC whose thioesterase activity has been demonstrated in vitro on acyl‐CoA derivatives, but whose physiological function in bacteria remains unknown. Therefore, YbgC could be a thioesterase active on some specific acyl‐ACPs. We then assigned a function to the ACP/YbgC pair by employing a proteomic approach derived from tandem affinity purification, the split tag method. This technique allowed us to purify proteins interacting with ACP and YbgC proteins at the same time. Interactions with PlsB, a sn‐glycerol‐3‐phosphate acyltransferase and PssA, a phosphatidylserine synthase, were identified and validated, showing that YbgC is involved in phospholipid metabolism. Furthermore, using an in vivo bacterial two‐hybrid interaction analysis, we showed for the first time that enzymes of the phospholipid synthesis pathway form a complex in the inner membrane. Taken together, these results describe an integrated protein network that could be involved in the coordination of phospholipid metabolism.
Growth hormone (GH) receptor knockout mice reveal actions of GH in lung development
Authors: Beyea Jason A. , Sawicki Grzegorz , Olson David M. , List Edward , Kopchick John J. , Harvey Steve 
Published: November 2005

AbstractThe presence of growth hormone (GH) and GH receptors (GHRs) in the lung suggests it is an autocrine/paracrine target site for pulmonary GH action and/or an endocrine site of pituitary GH action. Roles for GH in lung growth or pulmonary function are, however, uncertain. The possibility that pituitary and/or pulmonary GH have physiological roles in lung development has therefore been investigated in GHR knockout (KO or ‐/‐) mice, using a proteomics approach to determine if an absence of GH‐signaling affects the proteome of the developing lung. More than 600 proteins were detected by 2‐DE in the lungs of control [GHR (+/+)] and GHR (–/–) mice at the end of the alveolarization period (at day 14 postnatally). Of these, 39 differed significantly in protein content at thep>0.05 level [6 were of higher abundance in the GHR (–/–) group, 33 were of lower abundance] and 17 differed at thep>0.02 level [5 of higher abundance in the GHR (–/–) group, 12 of lower abundance] and 7 were definitively identified by MS. Vimentin, a protein involved in cellular proliferation, was reduced in content by approximately 75% in the lungs of the GHR (–/–) mice. Three proteins involved in oxidative protection [SH3 domain‐binding glutamic acid‐rich‐like protein, peroxiredoxin 6 (Prdx6), and isocitrate dehydrogenase 1] were also of lower content in the GHR (–/–) lungs (by approximately 88%, 81% and 70%, respectively). Prdx6 is also involved in lipid and surfactant metabolism, as is apolipoprotein A‐IV, the lung content of which was reduced by approximately 73% in these mice. Proteasome 26S ATPase subunit 4, a protein involved in the non‐lysosomal degradation of intracellular proteins, and electron flavoprotein alpha subunit , involved in intracellular metabolism, were also reduced in content in the lungs of the GHR (–/–) mice (by approximately 70% and 49%, respectively). These results therefore suggest that these proteins are normally dependent upon GH signaling, and that GH is normally involved in early lung growth, oxidative protection, lipid and energy metabolism and in proteasomal activity. These roles may reflect endocrine actions of pituitary GH and/or local autocrine/paracrine actions of GH produced within the lung.
Study of ring closure reaction of substituted phenyl N‐(2‐thiocarbamoylphenyl)carbamates catalysed by methoxide ion
Authors: Hanusek Jiří , Sedlák Miloš , Jansa Petr , Štěrba Vojeslav 
Published: November 2005

AbstractStudies were made of the kinetics of methoxide ion‐catalysed reactions of seven substituted phenyl N‐(2‐thiocarbamoylphenyl)carbamates, 4‐methoxyphenyl N‐(2‐thiocarbamoylphenyl)‐N‐(methyl)carbamate and five substituted phenyl N‐(4‐thiocarbamoylphenyl)carbamates, leading to the respective cyclisation products (i.e. 4‐thioxo‐1H,3H‐quinazolin‐2‐one or 1‐methyl‐4‐thioxo‐1H,3H‐quinazolin‐2‐one) and/or methanolysis product, i.e. methyl N‐(4‐thiocarbamoylphenyl)carbamate. The comparison of the rate constants, βlg, and ρ constants of the 2‐thiocarbamoyl derivatives (βlg = −1.15, ρ = 3.1 ± 0.1) and 4‐thiocarbamoyl derivatives (ρ = 4.6 ± 0.2, βlg = −1.55) shows that the ring closure reaction proceeds by the BAc2 mechanism with the splitting off of phenoxide anion being the rate‐limiting step, while the methanolysis follows the E1cB mechanism. The ring closure reaction of 4‐methoxyphenyl N‐(2‐thiocarbamoyl)‐N‐(methyl)carbamate proceeds kinetically in two steps, the respective rate constants differing by one order of magnitude. The NMR spectrum, spectral record and computational calculations of the ring closure reaction indicate that the process involves parallel reactions of two rotamers formed due to hindered rotation. Copyright © 2005 John Wiley & Sons, Ltd.
Detailed study of the ring‐opening metathesis polymerization of norbornene bearing a five‐ or six‐membered ring cyclic carbonate along with volume expansion
Authors: Hino Tetsuo , Inoue Naoto , Endo Takeshi 
Published: November 2005

AbstractThe ring‐opening metathesis polymerization (ROMP) of norbornene derivatives bearing five‐ or six‐membered cyclic carbonate (2 or 3) was carried out with a typical ruthenium catalyst [bis(tricyclohexylphosphine)benzylidene ruthenium(IV) dichloride], the so‐called first‐generation Grubbs catalyst, under various reaction conditions, to smoothly obtain the corresponding polyalkenamers (5 and 6) along with volume expansion. The number‐average molecular weights (Mn's), 10% weight loss decomposition temperatures, glass‐transition temperatures (Tg's), and volume expansion ratios of the resulting products depended on the polymerization conditions. The degree of volume expansion was mainly affected by Mn, Tg, and the cis/trans configuration of the exocyclic double bonds of the resulting polymers. The volume expansion was confirmed to specifically occur during the polymerization of the monomer bearing cyclic carbonate moieties, and similar ROMPs of monomers without cyclic carbonate, such as norbornene itself, the monomer 5,5‐bis(methoxymethyl)bicyclo[2.2.1]hept‐2‐ene, and the monomer endo‐N‐methylbicyclo[2.2.1]hept‐5‐ene‐2,3‐dicarboxylimide, proceeded along with volume shrinkage. Furthermore, an investigation of another type of polymerization, a vinyl‐type one, of monomer 2 suggested that the volume expansion specifically took place in the ring‐opening type of polymerization. In addition, the Sc(OTf)3‐mediated cationic ring‐opening reaction of the cyclic carbonate moiety of polyalkenamer 5 smoothly proceeded along with volume expansion or nearly zero volume shrinkage to yield the corresponding networked polymer. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 395–405, 2006
Atom transfer radical polymerization of styrene using the novel initiator ethyl 2‐N,N‐(diethylamino)dithiocarbamoyl‐butyrate
Authors: Zhang Wei , Zhu Xiulin , Zhu Jian , Chen Jianying 
Published: November 2005

AbstractThe atom transfer radical polymerizations (ATRPs) of styrene initiated by a novel initiator, ethyl 2‐N,N‐(diethylamino)dithiocarbamoyl‐butyrate (EDDCB), in both bulk and solution were successfully carried out in the presence of copper(I) bromide (CuBr) and N,N,N′,N″,N″‐pentamethyldiethylenetriamine at 115 °C. The polymerization rate was first‐order with respect to the monomer concentration, and the molecular weights of the obtained polymers increased linearly with the monomer conversions with very narrow molecular weight distributions (as low as 1.17) up to higher conversions in both bulk and solution. The polymerization rate was influenced by various solvents in different degrees in the order of cyclohexanone > dimethylformamide > toluene. The molecular weight distributions of the produced polymers in cyclohexanone were higher than those in dimethylformamide and toluene. The results of 1H NMR analysis and chain extension confirmed that well‐defined polystyrene bearing a photo‐labile N,N‐(diethylamino)dithiocarbamoyl group was obtained via ATRP of styrene with EDDCB as an initiator. The polymerization mechanism for this novel initiation system is a common ATRP process. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 32–41, 2006
Abilities of 2‐arylmethyloxy‐6‐cyanonaphthalene derivatives to initiate radical and cationic photopolymerizations
Authors: Tanaka Kenta , Akimoto Ryoichi , Igarashi Tetsutaro , Sakurai Tadamitsu 
Published: November 2005

AbstractAn investigation was undertaken to shed much light on the bond‐cleavage mode (heterolysis vs homolysis) of bichromophoric photoinitiators in styrene (St) and 1,2‐epoxycyclohexane (EpC) and then to develop a highly efficient hybrid‐type photoinitiator. Excited‐state 2‐(9‐anthrylmethyloxy)‐6‐cyanonaphthalene in toluene and 1,2‐dimethoxyethane, which were used instead of St and EpC, respectively, underwent both homolytic ArOCH2 bond cleavage and heterolytic ArOCH2 bond cleavage to give the corresponding radical‐pair and ion‐pair intermediates. The charge‐separated state characteristic of the naphthol chromophore in the singlet excited state was found to play a pivotal role in this heterolytic bond‐cleavage mode. An inspection of the radical (St) and cationic (EpC) photopolymerization behavior observed in the presence of some 2‐arylmethyloxy‐6‐cyanonaphthalenes led us to conclude that the aforementioned 9‐anthrylmethyloxy‐substituted naphthalene derivative is a candidate for a functional hybrid‐type photoinitiator containing no halogen and/or metal. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 25–31, 2006
Ring‐Opening and polymerization of 1‐[2′‐(heptaphenylcyclotetrasiloxanyl)ethyl]‐1,3,3,5,5‐pentamethylcyclotrisiloxane
Authors: Gädda Thomas M. , Weber William P. 
Published: November 2005

Abstract1‐[2′‐(Heptaphenylcyclotetrasiloxanyl)ethyl]‐1,3,3,5,5‐pentamethylcyclotetrasiloxane (II) was prepared from 1‐[2′‐(methyldichlorosilyl)ethyl]‐1,3,3,5,5,7,7‐heptaphenylcyclotetrasiloxane (I) and tetramethyldisiloxane‐1,3‐diol. Acid‐catalyzed ring‐opening of II in the presence of tetramethyldisiloxane gave 1,9‐dihydrido‐5‐[2′‐(heptaphenylcyclotetrasiloxanyl)ethyl]nonamethylpentasiloxane (III) and 1,9‐dihydrido‐3‐[2′‐(heptaphenylcyclotetrasiloxanyl)ethyl]nonamethylpentasiloxane (IV). Both acid‐ and base‐catalyzed ring‐opening polymerization of II gives highly viscous, transparent polymers. The structures of I–IV and polymers were determined by UV, IR, 1H, 13C, and 29Si NMR spectroscopy. In addition, molecular weights obtained by GPC and NMR end group analysis were confirmed with mass spectrometry. On the basis of 29Si NMR spectroscopy, the polymers appear to result exclusively from ring‐opening of the cyclotrisiloxane ring. No evidence for ring‐opening of the cyclotetrasiloxane ring was observed. Polymer properties were determined by DSC and TGA. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 137–146, 2006
Stimuli‐responsive polymers. VIII. Polyesters and poly(ester amides) containing azobenzene and chiral binaphthylene segments: Highly adaptive materials endowed with light‐, heat‐, and solvent‐regulated optical rotatory power
Authors: Jaycox Gary D. 
Published: November 2005

AbstractAzobenzene‐modified polyesters and poly(ester amide)s fitted with chiral, atropisomeric binaphthylene segments were prepared by a series of low‐temperature polycondensation reactions carried out in polar solvent media. When compared with their polyaramide counterparts studied earlier, these materials had significantly improved solubility behaviors and were readily dissolved by a wide range of organic solvents. In solution, each of these constructs underwent photoinduced oscillations in optical rotatory power when subjected to multiple UV‐light/visible‐light illumination cycles that drove trans↔cis isomerization reactions along their polymer chains. Light‐regulated chiroptical perturbations were dependent on polymer backbone structures and were further modulated by well‐coordinated temperature fluctuations and by the nature of the solvent medium employed. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 207–218, 2006
Copolymerization of N‐vinylcaprolactam and glycidyl methacrylate: Reactivity ratio and composition control
Authors: Qiu Xingping , Sukhishvili Svetlana A. 
Published: November 2005

AbstractFree‐radical copolymerizations of N‐vinylcaprolactam (VCL) and glycidyl methacrylate (GMA) were investigated to synthesize temperature‐responsive reactive copolymers with minimized compositional heterogeneity. The average copolymer composition was determined by Fourier transform infrared and nuclear magnetic resonance techniques. The reactivity ratios for VCL and GMA were found to be 0.0365 ± 0.0009 and 6.44 ± 0.36 by the Fineman–Ross method and 0.039 ± 0.006 and 6.75 ± 0.29 by the Kelen–Tudos method, respectively. When prepared by batch polymerization, VCL–GMA copolymers had a highly heterogeneous composition and fractions of different solubilities in water. The use of a gradual feeding technique, which included the sequential addition of more reactive GMA monomer into the reaction, yielded copolymers with much more homogeneous composition. The produced copolymers with 0.9 and 0.11 fractional GMA contents preserved their temperature‐responsive properties and precipitated from aqueous solutions when the temperature exceeded 31 °C. The GMA units in the VCL–GMA copolymers were capable of reacting with amino end‐functionalized poly(ethylene oxide) at room temperature to produce poly(N‐vinylcaprolactam)–poly(ethylene oxide) graft copolymers. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 183–191, 2006
Development of organotellurium‐mediated and organostibine‐mediated living radical polymerization reactions
Authors: Yamago Shigeru 
Published: November 2005

AbstractOrganotellurium‐mediated living radical polymerizations (TERPs) and organostibine‐mediated living radical polymerizations (SBRPs) provide well‐defined polymers with a variety of polar functional groups via degenerative chain‐transfer polymerization. The high controllability of these polymerizations can be attributed to the rapid degenerative‐transfer process between the polymer‐end radicals and corresponding dormant species. The versatility of the methods allows the synthesis of AB diblock, ABA triblock, and ABC triblock copolymers by the successive addition of different monomers. This review summarizes the current status of TERP and SBRP. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 1–12, 2006
New method of synthesis of electroactive polyamide with amine‐capped aniline pentamer in the main chain
Authors: Chao Danming , Lu Xiaofeng , Chen Jingyu , Zhao Xiaogang , Wang Lifeng , Zhang Wanjin , Wei Yen 
Published: November 2005

AbstractA novel way to prepare an electroactive polyamide (alternating copolymer) is presented. Well‐defined molecular structure polyamide with amine‐capped aniline pentamer in the main chain was obtained. The copolymer has been characterized by Fourier‐transform infrared (FTIR) spectra, 1H NMR, elemental analysis (EA), and gel permeation chromatography (GPC). Its chemical oxidation process was studied by UV–vis spectra and the electrochemical analysis was checked by cyclic voltammetry (CV). It was found that the obtained electroactive polyamide shows three redox peaks in the cyclic voltammetry, which is different from the polyaniline. Moreover, the thermal properties of the copolymer were evaluated by thermogravimetric analysis (TGA). The electrical conductivity is about 2.5 × 10−6 S cm−1 at room temperature. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 477–482, 2006
Preparation of ABC miktoarm star terpolymer containing poly(ethylene glycol), polystyrene, and poly(tert‐butylacrylate) arms by combining diels–alder reaction, atom transfer radical, and stable free radical polymerization routes
Authors: Durmaz Hakan , Karatas Figen , Tunca Umit , Hizal Gurkan 
Published: November 2005

AbstractThe ABC type miktoarm star terpolymer was prepared utilizing “core‐in” and “core‐out” methods via combination of Diels–Alder reaction (DA), stable free radical polymerization (SFRP), and atom transfer radical polymerization (ATRP). First, in DA reaction, poly(ethylene glycol)‐maleimide (PEG‐maleimide) precursor was reacted with succinic acid anthracen‐9‐ylmethyl ester 3‐(2‐bromo‐2‐methyl‐propionyloxy)‐2‐methyl‐2‐[2‐phenyl‐2‐(2,2,6,6‐tetramethyl‐piperidin‐1‐yloxy)‐ethoxy‐carbonyl]‐propyl ester, 8, to give DA adduct, 9, which has appropriate functional groups for SFRP and ATRP. Second, a previously obtained 9 was used as a macroinitiator for SFRP of styrene at 125 °C. As a third step, this PEG‐polystyrene (PEG‐PSt) precursor with a bromine functionality in the core was employed as a macroinitiator for ATRP of tert‐butylacrylate (tBA) in the presence of Cu(I)Br and pentamethyldiethylenetriamine at 80 °C to give ABC type miktoarm star terpolymer (PEG‐PSt‐PtBA) with controlled molecular weight and low polydispersity (Mw/Mn < 1.27). The obtained polymers were characterized by gel permeation chromatography and 1H NMR. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 499–509, 2006
Synthesis and characterization of amphiphilic copolymer of linear poly(ethylene oxide) linked with [poly(styrene‐co‐2‐hydroxyethyl methacrylate)‐graft‐poly(ε‐caprolactone)] using sequential controlled polymerization
Authors: Xu Xuewei , Huang Junlian 
Published: November 2005

AbstractA well‐defined amphiphilic copolymer of ‐poly(ethylene oxide) (PEO) linked with comb‐shaped [poly(styrene‐co‐2‐hydeoxyethyl methacrylate)‐graft‐poly(ε‐caprolactone)] (PEO‐b‐P(St‐co‐HEMA)‐g‐PCL) was successfully synthesized by combination of reversible addition‐fragmentation chain transfer polymerization (RAFT) with ring‐opening anionic polymerization and coordination–insertion ring‐opening polymerization (ROP). The α‐methoxy poly(ethylene oxide) (mPEO) with ω,3‐benzylsulfanylthiocarbonylsufanylpropionic acid (BSPA) end group (mPEO‐BSPA) was prepared by the reaction of mPEO with 3‐benzylsulfanylthiocarbonylsufanyl propionic acid chloride (BSPAC), and the reaction efficiency was close to 100%; then the mPEO‐BSPA was used as a macro‐RAFT agent for the copolymerization of styrene (St) and 2‐hydroxyethyl methacrylate (HEMA) using 2,2‐azobisisobutyronitrile as initiator. The molecular weight of copolymer PEO‐b‐P(St‐co‐HEMA) increased with the monomer conversion, but the molecular weight distribution was a little wide. The influence of molecular weight of macro‐RAFT agent on the polymerization procedure was discussed. The ROP of ε‐caprolactone was then completed by initiation of hydroxyl groups of the PEO‐b‐P(St‐co‐HEMA) precursors in the presence of stannous octoate (Sn(Oct)2). Thus, the amphiphilic copolymer of linear PEO linked with comb‐like P(St‐co‐HEMA)‐g‐PCL was obtained. The final and intermediate products were characterized in detail by NMR, GPC, and UV. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 467–476, 2006
Synthesis of well‐defined naphthalene and photo‐labile group‐labeled polystyrene via ATRP
Authors: Zhang Wei , Zhou Nianchen , Zhu Jian , Sun Bin , Zhu Xiulin 
Published: November 2005

AbstractThe atom transfer radical polymerizations of styrene were successfully carried out in bulk and solution, respectively, at 115 °C, with a novel photoiniferter reagent, (1‐naphthyl)methyl N,N‐diethyldithiocarbamate (NMDC), as an initiator in the presence of copper (I) bromide and N,N,N′,N″,N″‐pentamethyldiethylenetriamine. The results showed that NMDC was an effective initiator with high initiation efficiency for ATRP of St. The polymerization rate was first‐order with respect to the monomer concentration and the molecular weights of the obtained polystyrene (PS) increased linearly with the monomer conversion, with very narrow molecular weight distributions (Mw/Mn = 1.07–1.29). The functionalized naphthalene‐labeled PS bearing N,N‐(diethylamino)dithiocarbamoyl group which was confirmed by 1H NMR analysis, and chain extension of the PS exhibited fluorescence and ultraviolet absorption in chloroform (CHCl3). © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 510–518, 2006
Dibenzyl trithiocarbonate mediated reversible addition–fragmentation chain transfer polymerization of acrylonitrile
Authors: Liu Xiao‐Hui , Zhang Gui‐Bao , Lu Xian‐Feng , Liu Jing‐Yu , Pan Ding , Li Yue‐Sheng 
Published: November 2005

AbstractReversible addition–fragmentation chain transfer polymerization has been successfully applied to polymerize acrylonitrile with dibenzyl trithiocarbonate as the chain‐transfer agent. The key to success is ascribed to the improvement of the interchange frequency between dormant and active species through the reduction of the activation energy for the fragmentation of the intermediate. The influence of several experimental parameters, such as the molar ratio of the chain‐transfer agent to the initiator [azobis(isobutyronitrile)], the molar ratio of the monomer to the chain‐transfer agent, and the monomer concentration, on the polymerization kinetics and the molecular weight as well as the polydispersity has been investigated in detail. Matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry and 1H NMR analyses have confirmed the chain‐end functionality of the resultant polymer. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 490–498, 2006
Neodymium oxide‐assisted melt free‐radical grafting of maleic anhydride on isotactic‐polypropylene by reactive extrusion
Authors: Zhu Lianchao , Tang Gongben , Shi Qiang , Cai Chuanlun , Yin Jinghua 
Published: November 2005

AbstractRare earth oxide, neodymium oxide (Nd2O3), ‐assisted melt free‐radical grafting of maleic anhydride (MAH) on isotactic‐polypropylene (i‐PP) was carried out by reactive extrusion. The experimental results reveal that the addition of Nd2O3 into reactive system leads to an enhancement of the grafting degree of MAH, along with an elevated degradation of i‐PP matrix. When Nd2O3 content is 4.5 mmol %, the increment of the grafting degree of MAH (maximally) is up to about 30% compared with that of the related system without adding Nd2O3, while the severest degradation of i‐PP matrix simultaneously occurs. On the basis of the reaction mechanism of PP‐g‐MAH proposed before, the sequence of β‐scission and grafting reaction is discussed in detail. It is found that, for the reactive system studied, most tertiary macroradicals first undergo β‐scission, and then, grafting reaction with MAH takes place at the new radical chain ends. The imported Nd2O3 has no effect on the aforementioned reaction mechanism, whereas it enhances the initiating efficiency of the initiator, dicumyl peroxide (DCP). We tentatively explain the experimental results by means of synergistic effect between DCP and Nd2O3. It is calculated that the synergistic effect is maximal when the molar ratio of DCP to Nd2O3 is approximately 1:6. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 134–142, 2006