bluuebunny/crossref_metadata_2025 huggingface dataset:
3‐Methylarginine from Pseudomonas syringae pv. syringae 22d/93 Suppresses the Bacterial Blight Caused by Its Close Relative Pseudomonas syringae pv. glycinea
Authors: Braun Sascha D. , Völksch Beate , Nüske Jörg , Spiteller Dieter
Published: July 2008

The epiphyte Pseudomonas syringae pv. syringae 22d/93 (Pss22d) produces a toxin that strongly inhibits the growth of its relative, the plant pathogen P. syringae pv. glycinea. The inhibition can be overcome by supplementing the growth medium with the essential amino acid, L‐arginine; this suggests that the toxin acts as an inhibitor of the arginine biosynthesis. The highly polar toxin was purified by bioassay‐guided fractionation using ion‐exchange chromatography and subsequent RP‐HPLC fractionation. The structure of the natural product was identified by HR‐ESI‐MS, HR‐ESI‐MS/MS, and NMR spectroscopy experiments as 3‐methylarginine. This amino acid has previously only been known in nature as a constituent of the peptide lavendomycin from Streptomyces lavendulae. Results of experiments in which labeled methionine was fed to Pss22d indicated that the key step in the biosynthesis of 3‐methylarginine is the introduction of the methyl group by a S‐adenosylmethionine (SAM)‐dependent methyltransferase. Transposon mutagenesis of Pss22d allowed the responsible SAM‐dependent methyltransferase of the 3‐methylarginine biosynthesis to be identified.
Oxidation of Guanine by Carbonate Radicals Derived from Photolysis of Carbonatotetramminecobalt(III) Complexes and the pH Dependence of Intrastrand DNA Cross‐Links Mediated by Guanine Radical Reactions
Authors: Crean Conor , Lee Young Ae , Yun Byeong Hwa , Geacintov Nicholas E. , Shafirovich Vladimir
Published: July 2008

The carbonate radical anion CO3.− is a decomposition product of nitrosoperoxycarbonate derived from the combination of carbon dioxide and peroxynitrite, an important biological byproduct of the inflammatory response. The selective oxidation of guanine in DNA by CO3.− radicals is known to yield spiroiminodihydantoin (Sp) and guanidinohydantoin (Gh) products, and also a novel intrastrand cross‐linked product: 5′‐d(CCATCG*CT*ACC), featuring a linkage between guanine C8 (G*) and thymine N3 (T*) atoms in the oligonucleotide (Crean et al., Nucleic Acids Res. 2008, 36, 742–755). Involvement of the T‐N3 (pKa of N3‐H is 9.67) suggests that the formation of 5′‐d(CCATCG*CT*ACC) might be pH‐dependent. This hypothesis was tested by generating CO3.− radicals through the photodissociation of carbonatotetramminecobalt(III) complexes by steady‐state UV irradiation, which allowed for studies of product yields in the pH 5.0–10.0 range. The yield of 5′‐d(CCATCG*CT*ACC) at pH 10.0 is ∼45 times greater than at pH 5.0; this is consistent with the proposed mechanism, which requires N3(H) thymine proton dissociation followed by nucleophilic addition to the C8 guanine radical.
Use of a Halogenase of Hormaomycin Biosynthesis for Formation of New Clorobiocin Analogues with 5‐Chloropyrrole Moieties
Authors: Heide Lutz , Westrich Lucia , Anderle Christine , Gust Bertolt , Kammerer Bernd , Piel Jörn
Published: July 2008

The depsipeptide antibiotic hormaomycin, which is produced by Streptomyces griseoflavus W‐384, contains a 5‐chloropyrrole moiety. In the producer strain we identified the gene hrmQ that shows sequence similarity to FADH2‐dependent halogenases. This gene was cloned and heterologously expressed in Streptomyces roseochromogenes var. oscitans DS12.976, which is the producer of the aminocoumarin antibiotic clorobiocin, which contains a 5‐methylpyrrole moiety. For the present experiment, we used a mutant of this strain in which the respective pyrrole‐5‐methyltransferase had been inactivated. Expression of the halogenase hrmQ in this mutant strain led to the formation of two new clorobiocin derivatives that carried a 5‐chloropyrrole moiety. These compounds were isolated on a preparative scale, their structures were elucidated by 1H NMR spectroscopy and mass spectrometry, and their antibacterial activity was determined. The substrate of HrmQ is likely to be a pyrrole‐2‐carboxyl‐S‐[acyl carrier protein] thioester. If this assumption is true, this study presents the first experiment in combinatorial biosynthesis that uses a halogenase that acts on an acyl carrier protein‐bound substrate.
Chiral recognition of ethers by NMR spectroscopy
Authors: Duddeck Helmut , Díaz Gómez Edison
Published: July 2008

Enantiomers of chiral ethers and acetals are notoriously difficult to differentiate because their reactivity is low and they are poor donors to any Lewis acid or metal ion. As an exception, epoxides are somewhat better donors. This review describes the properties of ethers, explains NMR methods for their chiral recognition and describes successful examples of ether differentiation. The majority of literature reports deals with chiral lanthanide shift reagents and dirhodium tetracarboxylate complexes, which were used as enantiopure auxiliaries to create diastereomeric adducts with dispersed 1H and 13C NMR signals. The various methods are compared as to which is best suited for which purpose. Chirality, 2009. © 2008 Wiley‐Liss, Inc.
Gas‐phase enantioselective reactions in noncovalent ion‐molecule complexes
Authors: Speranza Maurizio , Gasparrini Francesco , Botta Bruno , Villani Claudio , Subissati Deborah , Fraschetti Caterina , Subrizi Fabiana
Published: July 2008

Noncovalent diastereomeric ion‐molecule complexes are produced in the gas phase and are ideal for the study of chiral recognition in the absence of complicating solvent and counterion effects. This review article describes the state‐of‐art in this field with special emphasis on the most recent mass spectrometric studies of the structure, dynamics, and reactivity of diastereomeric ion/molecule aggregates. Chirality, 2009. © 2008 Wiley‐Liss, Inc.
A new water soluble Zn‐salophen derivative as a receptor for α‐aminoacids: Unexpected chiral discrimination
Authors: Dalla Cort Antonella , De Bernardin Paolo , Schiaffino Luca
Published: July 2008

A new water soluble zinc‐salophen complex with appended D‐glucose moieties was synthesized and characterized. Its binding properties toward six aminoacids were investigated by UV‐vis spectrophotometric titrations. Association constants showed to be unfavorably affected by increasing steric hindrance of the side chain. Quite surprisingly, different association constants were measured for the L and D enantiomers. These data suggest that aminoacids are bound via two interactions, zinc‐carboxylate coordination and two hydrogen bonds between the ammonium group of the aminoacid and two oxygen atoms of one D‐glucose moiety. Such conclusion is supported by the result of semiempirical (PM3) calculations. Notably, the KL/KD value of 9.6 observed for the association of phenylalanine rivals with the highest values found for the chiral recognition of aminoacids in water. Chirality, 2009. © 2008 Wiley‐Liss, Inc.
Assessment of configurational and conformational properties of naringenin by vibrational circular dichroism
Authors: Abbate Sergio , Burgi Luigi Filippo , Castiglioni Ettore , Lebon France , Longhi Giovanna , Toscano Eleonora , Caccamese Salvatore
Published: July 2008

The electronic circular dichroism (ECD) and vibrational circular dichroism (VCD) spectra of both enantiomers of naringenin (4′,5,7‐trihydroxyflavanone) in acetonitrile solution have been measured. The enantiomers were obtained by chiral HPLC separation of the racemic sample. DFT calculations have been performed for relevant conformers and subsequent evaluations of VCD spectra are compared with VCD experiments: safe assignment of the absolute configuration is provided, based in particular on the VCD data. The relevance of the rotational conformers of the hydroxyl groups and of the mobility of phenol moiety is studied: based on this, we provide a first interpretation of the observed intense and broad couplet at 1325/1350 cm−1. Four conformers contribute to this pattern with different sign and amplitude as shown by DFT calculations. Time dependent DFT calculations have been performed and compared with ECD experimental data, under the same assumption of conformational properties and mobilities investigated by VCD. Chirality, 2009. © 2008 Wiley‐Liss, Inc.
Immobilization of (1S,2R)‐(+)‐2‐amino‐1,2‐diphenylethanol derivates on aminated silica gel with different linkages as chiral stationary phases and their enantioseparation evaluation by HPLC
Authors: Yin Chuan‐Qi , He Bao‐Jiang , Li Shi‐Rong , Liu Yong‐Qiong , Bai Zheng‐Wu
Published: July 2008

A chiral selector was prepared through the reaction between (1S,2R)‐(+)‐2‐amino‐1,2‐diphenylethanol and phenyl isocyanate. This selector was immobilized on aminated silica gel, respectively, with bifunctional group linkers of 1,4‐phenylene diisocyanate, methylene‐di‐p‐phenyl diisocyanate, and terephthaloyl chloride to produce corresponding three chiral stationary phases. The prepared compounds and chiral stationary phases were characterized by FT‐IR, elemental analysis, 1H NMR, and solid‐state 1H NMR. The enantioseparation ability of these chiral stationary phases was evaluated with structurally various chiral compounds. The chiral stationary phase prepared with 1,4‐phenylene diisocyanate as linker showed excellent enantioseparation ability. The influence of different linkages on the enantioseparation was discussed. Chirality, 2009. © 2008 Wiley‐Liss, Inc.
Chemoenzymatic and microbial dynamic kinetic resolutions
Authors: Kamaruddin Azlina Harun , Uzir Mohamad Hekarl , Aboul‐Enein Hassan Y. , Halim Hairul Nazirah Abdul
Published: July 2008

This review tracks a decade of dynamic kinetic resolution developments with a biocatalytic inclination using enzymatic/microbial means for the resolution part followed by the racemization reactions either by means of enzymatic or chemocatalyst. These fast developments are due to the ability of the biocatalysts to significantly reduce the number of synthetic steps which are common for conventional synthesis. Future developments in novel reactions and products of dynamic kinetic resolutions should consider factors that are needed to be extracted at the early synthetic stage to avoid inhibition at scale‐up stage have been highlighted. Chirality, 2009. © 2008 Wiley‐Liss, Inc.
Asymmetric addition of phenylacetylene to aromatic ketones catalyzed by zinc or titanium complexes with chiral hydroxysulfonamide
Authors: Zhou Yi‐Feng , Han Zhi‐Jian , Qiu Li , Liang Jin‐Yan , Ren Feng‐Bo , Wang Rui
Published: July 2008

Various new chiral hydroxysulfonamide ligands (3a–3n, 4a–4d) were prepared. Compounds 3a, 3g, 3i, 3k–3n, 4a–4d could accelerate the reaction and reduce reaction time, and 3a, 3g, 3i, 3k–3n catalyzed the reaction without titanium. The results obtained were promising in terms of yields and enantiomeric excesses (3k up to 85% ee, 4a up to 83% ee). Chirality, 2009. © 2008 Wiley‐Liss, Inc.
Stereoselective plasma protein binding and target tissue distribution of clausenamide enantiomers in rats
Authors: Zhu Chuan Jiang , Zhang Jun Tian
Published: July 2008

Stereoselective differences in pharmacokinetics between clausenamide (CLA) enantiomers have been found after intravenous and oral administration of each enantiomer to rats. The differences could be associated with protein binding of CLA enantiomers. By equilibrium dialysis methods, the binding of CLA enantiomers to rat plasma protein was investigated. The results showed that mean percentages of (−) and (+)CLA in the bound form were 28.5% and 38.0%, respectively, indicating that the unbound fraction of (−)CLA was higher than that of (+)CLA, which provided an explanation for stereoselective pharmacokinetics of CLA enantiomers in rats. The results also showed that there were species differences in plasma protein binding of (−)‐isomer between rats (28.5%) and rabbits (47.2%). Furthermore, effects of plasma protein binding on the distribution of CLA enantiomers to their possible target tissues were observed. The amount of (−)CLA in brain was greater than that of (+)CLA 15 min after administration of each enantiomer to rats. But the results were reverse at 4 h postdose. Further studies in distributional kinetics showed that (−)CLA had a more rapid absorption and distribution to hippocampus, cortex, and cerebellum than (+) CLA. (+)CLA had greater values for Tmax, t1/2β, and AUC0→∞, and smaller ones for CL/F and Vd/F than its antipode. The data indicated that the distribution of (−) and (+)CLA in their target tissues was stereoselective. The stereoselective distribution might be involved in the metabolism and transport of two enantiomers in the central nerve system. Chirality, 2009. © 2008 Wiley‐Liss, Inc.
High performance liquid chromatographic enantioseparation of chiral bridged polycyclic compounds on chiralcel OD‐H and chiralpak OT(+)
Authors: Peluso Paola , Cossu Sergio , Moretto Flavio , Marchetti Mauro
Published: July 2008

The HPLC enantiomeric separation of 29 racemic bridged polycyclic compounds was examined on commercially available Chiralcel OD‐H and Chiralpak OT(+) columns. The separations were evaluated under normal‐phase mode (hexane containing mobile phase) for Chiralcel OD‐H and under normal‐phase as well as under reversed‐phase mode (pure MeOH, temperature 5°C) for Chiralpak OT(+). Almost all compounds were resolved either on Chiralcel OD‐H or on Chiralpak OT(+), in some cases on both. The use of trifluoroacetic acid (TFA), as modifier of the hexanic mobile phase, had a beneficial effect on the enantioseparation of some polar and acidic compounds on Chiralcel OD‐H. The influence of small chemical structural modifications of the analytes on the enantioseparation behavior is discussed. A structure–retention relationship has been observed on both stationary phases. This chromatographic evaluation may provide some information about the chiral recognition mechanism: in the case of Chiralcel OD‐H, hydrogen bonding, π‐π and distereoselective repulsive are supposed to be the major analyte‐CSP interactions. In the case of Chiralpak OT(+), a reversed‐phase enantioseparation could take place through hydrophobic interactions between the aromatic moiety of the analytes and the chiral propeller structure of the CSP. The synthesis of some unknown racemic bromobenzobicyclo[2.2.1] analytes is also described. Chirality, 2009. © 2008 Wiley‐Liss, Inc.
L‐Selectin‐deficient SJL and C57BL/6 mice are not resistant to experimental autoimmune encephalomyelitis
Authors: Uboldi Chiara , Döring Axinia , Alt Carsten , Estess Pila , Siegelman Mark , Engelhardt Britta
Published: July 2008

L‐selectin has been suggested to play a role in the pathogenesis of experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis. Here we demonstrate that L‐selectin–/– SJL mice are susceptible to proteolipid protein (PLP)‐induced EAE because the compromised antigen‐specific T cell proliferation in peripheral lymph nodes is fully compensated by the T cell response raised in their spleen. Transfer of PLP‐specific T cells into syngeneic recipients induced EAE independent of the presence or absence of L‐selectin on PLP‐specific T cells or in the recipient. Leukocyte infiltration into the central nervous system parenchyma was detectable independent of the mode of disease induction and the presence or absence of L‐selectin. In addition, we found L‐selectin–/– C57BL/6 mice to be susceptible to myelin oligodendrocyte glycoprotein‐induced EAE. Taken together, we demonstrate that in SJL and C57BL/6 mice L‐selectin is not required for EAE pathogenesis. The apparent discrepancy of our present observation to previous findings, demonstrating a role of L‐selectin in EAE pathogenesis in C57BL/6 mice or myelin‐basic protein (MBP)‐specific TCR‐transgenic B10.PL mice, may be attributed to background genes rather than L‐selectin and to a unique role of L‐selectin in EAE pathogenesis in MBP‐TCR‐transgenic mice.
Hydrogen Bonding and Anion Binding in Structures of Tris(pyrazolyl)boratenickel(II) and Phosphate Esters
Authors: Santana M. Dolores , López‐Banet Luisa , García Gabriel , García Luís , Pérez José , Liu Malva
Published: July 2008

This paper presents the syntheses, crystal structures and spectroscopic properties of a series of nickel(II) complexes containing hydrotris(3,5‐dimethylpyrazolyl)borate and phosphate esters: [Tp*Ni(Hpz*)2(L)][(RO)2PO2] [R = Et, Bu; L = H2O (1), (BuO)2P(O)OH (2)] and [Tp*Ni(Hpz*)(H2O)2][(EtO)2PO2] (5) {Tp* = hydrotris(3,5‐dimethylpyrazolyl)borate, Hpz* = 3,5‐dimethylpyrazole}. The complexes [Ni(Tp*)2] (3) and [(Tp*Ni)2(μ‐pz*)(μ‐OH)](4) were also prepared and fully characterized. X‐ray crystallographic studies of 1 and 2 reveal that the pyrazole moieties are hydrogen bonded to the guest phosphate ester anion. In complex 5, the phosphate anion is hydrogen‐bonded by two O–H groups of the water molecules. Their behavior in solution was investigated by 1D and 2D 1H NMR spectroscopic techniques. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Lanthanide Complexes of 2,2′,2″‐(10‐{[Hydroxy(phenyl)phosphoryl]methyl}‐1,4,7,10‐tetraazacyclododecan‐1,4,7‐triyl)triacetic Acid: Structural Characterisation of Intermediates from the Proposed Complexation Mechanism in the Systems of LnIII‐dota‐Type Ligands
Authors: Vojtíšek Pavel , Rohovec Jan , Klimentová Jana
Published: July 2008

The crystal and molecular structures of ten lanthanide complexes of H4do3aPPh [2,2′,2″‐(10‐{[hydroxy(phenyl)phosphoryl]methyl}‐1,4,7,10‐tetraazacyclododecan‐1,4,7‐triyl)triacetic acid] are presented here. These complexes constitute a new type of coordination compounds within the Ln‐dota family. They represent an intermediate stage on the way from the ligand to the classical in‐cavity complexes. The important role of intramolecular H‐bonds for the process was observed. These intermediate complexes in the solid state form several isostructural groups with the different coordination polyhedra (square antiprisma or dodecahedron) of lanthanide ions. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Copper Zeolites as Green Catalysts for Multicomponent Reactions of Aldehydes, Terminal Alkynes and Amines: An Efficient and Green Synthesis of Propargylamines
Authors: Patil Meghshyam K. , Keller Murielle , Reddy Benjaram M. , Pale Patrick , Sommer Jean
Published: July 2008

CuI‐modified zeolites, especially CuI‐USY, have proved to be very efficient catalysts in multicomponent reactions, allowing for a solvent‐free synthesis of propargylamines from aldehydes, amines, and terminal alkynes. With a heterogeneous catalyst and in the absence of solvent, this process is among the greenest ever reported. A mechanism has been proposed for this three‐component reaction.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Aryl Trialkylsilyl Ketenes: Acid‐Catalyzed Synthesis from 1‐Aryl‐2‐diazo‐2‐trialkylsilylethanones and Their Conversion into 3‐Silyl‐1‐silyloxyallenes
Authors: Bucher Stefan M. , Brückmann Ralf , Maas Gerhard
Published: July 2008

Aryl‐substituted α‐silyl α‐diazo ketones are readily transformed into aryl silyl ketenes in the presence of a catalytic amount of triflic acid. Thus, a convenient method to prepare these silyl ketenes becomes available, which combines two steps, silylation of an aryl diazomethyl ketone and acid‐induced Wolff rearrangement of the formed α‐silyl α‐diazo ketone, in a one‐pot procedure. It appears that the trialkylammonium salt, which is formed in the silylation step, can also catalyze the Wolff rearrangement, but distinctly more slowly than the proton acid. The silyl ketenes react smoothly with α‐silyl α‐diazo ketones to form 3‐silyl‐1‐silyloxyallenes in fairly good yields. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Electrochemical Characterization of Self‐Assembled Monolayer of a Novel Manganese Tetrabenzylthio‐Substituted Phthalocyanine and Its Use in Nitrite Oxidation
Authors: Matemadombo Fungisai , Griveau Sophie , Bedioui Fethi , Nyokong Tebello
Published: July 2008

Manganese phthalocyanine MnPc(SPh)4 has been synthesized and used to form self assembled monolayers on gold electrodes. The well packed SAM monolayer was characterized by analyzing the blocking of a number of Faradic processes by cyclic voltammetry, evaluating the electrical characteristics of the modified electrode by electrochemical impedance and imaging the modified surface by electrochemical scanning microscopy. Finally, MnPc(SPh)4‐SAM modified electrode displayed an electrocatalytic behavior toward the oxidation of nitrite.
The Fabrication and Characterization of a Bismuth Nanoparticle Modified Boron Doped Diamond Electrode and Its Application to the Simultaneous Determination of Cadmium(II) And Lead(II)
Authors: Toghill Kathryn E. , Wildgoose Gregory G. , Moshar Amir , Mulcahy Chris , Compton Richard G.
Published: July 2008

We report the simultaneous electroanalytical determination of Pb2+ and Cd2+ by square‐wave anodic stripping voltammetry (SWASV) using a bismuth nanoparticle modified boron doped diamond (Bi‐BDD) electrode. Bi deposition was performed in situ with the analytes, from a solution of 0.1 mM Bi(NO3)3 in 0.1 M HClO4 (pH 1.2), and gave detection limits of 1.9 μg L−1 and 2.3 μg L−1 for Pb(II) and Cd(II) respectively. Pb2+ and Cd2+ could not be detected simultaneously at a bare BDD electrode, whilst on a bulk Bi macro electrode (BiBE) the limits of detection for the simultaneous determination of Pb2+ and Cd2+ were ca. ten times higher.
Dynamically coated silica monolith with ionic liquids for capillary electrochromatography
Authors: Tian Yun , Feng Rui , Liao Liping , Liu Hanlan , Chen Hao , Zeng Zhaorui
Published: July 2008

An ionic liquid, 1‐butyl‐3‐methylimidazolium tetrafluoroborate ([BMIM][BF4]) was introduced as dynamic coating of a silica monolithic column for capillary electrochromatography of phenols and nucleoside monophosphates. The run‐to‐run and column‐to‐column repeatability of migration time for six phenols were satisfactory on this column with relative standard deviation values less than 0.90 and 4.31%, respectively. Anodic electroosmotic flow (EOF) was observed, which increased with the increase of [BMIM][BF4] concentration within 120 mM and when [BMIM][BF4] concentration was above 120 mM, EOF leveled off due to the saturation of [BMIM][BF4] on the monolith. Efficient separation of phenols and nucleoside monophosphates on this dynamically coated monolithic column was obtained, compared with a dynamically coated fused‐silica column and unmodified silica monolithic column. The retention behavior of uncharged phenols is mainly manipulated by hydrophobic interactions due to the presence of butyl groups, and that of nucleoside monophosphates is governed by the electrostatic attraction mechanism based on the interaction between positively charged [BMIM][BF4] moieties and negatively charged phosphate groups. In addition, silica matrix also contributes to the separation resolution.
Comparative study of the biosorption of cadmium(II), chromium(III), and lead(II) by olive stone
Authors: Hernáinz F. , Calero M. , Blázquez G. , Martín‐Lara M.A. , Tenorio G.
Published: July 2008

This research focuses on potential of using olive stone as a low‐cost biosorbent, for cadmium, chromium, and lead removal from aqueous solutions in a batch system as a function of pH, contact time, and temperature. Experimental data were tested in terms of biosorption kinetics using pseudo‐second‐order kinetic model. The results showed that the biosorption processes of the three metal ions followed well pseudo‐second‐order kinetics at 25, 40, and 60°C and for a metal initial concentration of 10 mg/L. The activation energy of biosorption (E) was determined as 7.09 kJ/mol for Cd(II), 12.39 kJ/mol for Cr(III), and 10.29 kJ/mol for Pb(II) indicating that the biosorption of these metal ions was taken place mainly by physical interactions. The equilibrium biosorption was also studied at these temperatures applying Sips isotherm model. Using the Sips constant, b, the thermodynamic parameters were calculated. The values of these parameters showed that the biosorption of Cd(II), Cr(III), and Pb(II) ions by olive stone was feasible and spontaneous and reflected the endothermic nature of the process for the removal of Cr(III) and Pb(II) except Cd(II). © 2008 American Institute of Chemical Engineers Environ Prog, 2008
Where will China go? A viewpoint based on an analysis of the challenges of resource supply and pollution
Authors: Yuan Zengwei , Jiang Weili , Liu Beibei , Bi Jun
Published: July 2008

Relying on the multiple inputs of natural resource and energy, as well as the transformation from a centrally planned economy to a market‐based economy and open policy, China made a great economic growth in the last few decades and became one of the most important world economic powers. However, the rapid economic growth has engendered serious natural resource depletion and pollution. Pollution and ecological degradation are becoming essential obstacles for China's further growth. Under the situation, the concept of circular economy (CE) was promoted in China as a new development strategy to alleviate the shortage of resource supply by improving the resource productivity and the eco‐efficiency of production and consumption, which will accelerate the economic transformation from economic growth to economic development. The difference of the two modes is that economic growth relies on a continuing increase of resource inputs while economic development relies on the improvement of efficiency (resource productivity and eco‐efficiency). © 2008 American Institute of Chemical Engineers Environ Prog, 2008
Hall effects for MHD Oldroyd 6‐constant fluid flows using finite element method
Authors: Sajid M. , Mahmood R. , Hayat T. , Siddiqui A. M.
Published: July 2008

This paper numerically investigates the influence of Hall current on the steady flows of an Oldroyd 6‐constant fluid between concentric cylinders. The flow analysis has been performed by employing finite element method. Two flow problems are considered. These problems have been recently solved by Rana et al. (Chaos, Solitons and Fractals, in press). Here the main equation governing the flow problems in (Chaos, Solitons and Fractals, in press) is corrected first and then used in the simulation. Finally, the interesting observations are obtained by plotting graphs. Copyright © 2008 John Wiley & Sons, Ltd.
Direct Electrochemistry of CueO and Its Mutants at Residues to and Near Type I Cu for Oxygen‐Reducing Biocathode
Authors: Miura Y. , Tsujimura S. , Kurose S. , Kamitaka Y. , Kataoka K. , Sakurai T. , Kano K.
Published: July 2008

CueO, a multi‐copper oxidase (MCO) occurring in Escherichia coli, catalyses a four‐electron reduction of O2 in a direct electron transfer (DET) mechanism with very high electrocatalytic activity on carbon aerogel electrodes. However, the overpotential of CueO is greater than that in other MCOs. By understanding the redox properties of CueO, we attempted to reduce this overpotential. Direct electrochemistry of CueO on carbon aerogel electrodes showed a pair of redox waves derived from the type I (T1) Cu site with a redox potential ($E {^{\circ \prime} \atop {\rm T1}} $) of 0.28 V versus Ag|AgCl at pH 5.0. Dependence of $E {^{\circ \prime} \atop {\rm T1}} $ on pH suggests the participation of proton transfer and acid–base equilibrium of some amino acid residue. The shape of the catalytic current is consistent with the T1 site being an inlet of electrons in the DET bioelectrocatalysis of O2, in which case the overpotential could be reduced by shifting $E {^{\circ \prime} \atop {\rm T1}} $ towards the positive potential. To achieve this, we created mutants of CueO at M510, which is the axial ligand of the T1 Cu, and at D439, which forms a hydrogen bond with His443 coordinated with the T1 Cu. Two mutants, M510L and D439A, successfully reduced the overpotential.
Pretreatment prediction of virological response to peginterferon plus ribavirin therapy in chronic hepatitis C patients using viral and host factors
Authors: Shirakawa Haruaki , Matsumoto Akihiro , Joshita Satoru , Komatsu Michiharu , Tanaka Naoki , Umemura Takeji , Ichijo Tetsuya , Yoshizawa Kaname , Kiyosawa Kendo , Tanaka Eiji
Published: July 2008

The interferon sensitivity determining region (ISDR) of the hepatitis C virus (HCV) and T-helper type 1 and type 2 (Th1/Th2) ratio were analyzed along with other host and viral factors for their ability to predict the response of patients with chronic hepatitis C to pegylated interferon alpha-2b (Peg-IFN) and ribavirin (RBV) combination therapy. A total of 120 chronic hepatitis C patients with genotype 1 HCV and high baseline viral loads who were to undergo combination therapy scheduled for 48 weeks were enrolled. Sustained virologic response (SVR) was achieved in 54 (45%) of the 120 patients. The pretreatment factors significantly associated with SVR by logistic regression analysis were ISDR mutant [odds ratio (OR) = 86.0,

P

= 0.0008], Th1/Th2 ratio ≤ 15.5 (OR = 9.6,

P

= 0.0021), body weight 59 kg, and neutrophil count 2,300/μL. A logistic regression model to estimate SVR before combination therapy was constructed using these four factors. Patients fell into three groups when plotted according to estimated and actual SVR rates: actual SVR rate was 91% (32/35) in the high sensitivity group, 41% (15/37) in the intermediate sensitivity group, and 15% (7/48) in the low sensitivity group. Rapid or early virological responses were seen in 80% of patients with high sensitivity and who achieved SVR but were found in only 40% of patients with intermediate or low sensitivity. Null- and very late virological responses were quite rare in the high sensitivity group. In conclusion, a logistic regression model that includes the sequence of ISDR of the HCV, Th1/Th2 ratio, body weight, and neutrophil count can be useful for accurately predicting actual SVR rate before combination therapy. (Hepatology 2008;48:1753-1760.)
Thymidylate synthase genotyping is more predictive for therapy response than immunohistochemistry in patients with colon cancer
Authors: Gosens Marleen J. , Moerland Elna , Lemmens Valery P. , Rutten Harm T. , Tan‐Go Ivonne , van den Brule Adriaan J.
Published: July 2008

Thymidylate synthase (TS) is a potentially valuable marker for therapy response since it is the molecular target of 5‐fluorouracil (5‐FU). TS can be analyzed at the DNA (gene polymorphisms and amplification) and protein level (immunohistochemistry). This study investigated the predictive role of TS at the DNA and protein levels in patients with N+colon cancer (n= 38). Tumor and normal tissues were genotyped using PCR for variable number of tandem repeats (VNTR), a single nucleotide polymorphism (SNP) in the 3R allele and a 6 bp deletion (1494del6) in theTSgene. Tumor tissues were additionally analyzed for loss of heterozygosity (VNTR polymorphism). A newly developed real time PCR assay was used to detect the presence ofTSgene amplifications in tumor tissues. VNTR analysis in normal tissue was significantly associated with distant tumor recurrence (8% for 2R/2Rvs.52% for patients carrying a 3R allele,p= 0.038) and cancer‐specific survival (p= 0.021). IHC was not found to be significantly associated with patients' outcome. No correlations betweenTSgene polymorphisms and IHC were found. However,TSgene amplification was correlated with a strong IHC staining intensity. In conclusion, this study indicates that DNA based analysis is more predictive for patients' outcome than TS IHC. © 2008 Wiley‐Liss, Inc.
Sustainable water saving: new concept of modern agricultural water saving, starting from development of Xinjiang's agricultural irrigation over the last 50 years
Authors: Ruisen Zhong , Xinguang Dong , Yingjie Ma
Published: July 2008

This paper analyses first the state of water land exploitation and water saving irrigation in Xinjiang over the last 50 years. A fairly severe situation of water resources utilization exists in Xinjiang, and so agricultural water saving provides an important way of solving the problem. Taking a comprehensive view of development of agricultural irrigation in Xinjiang over the last 50 years, surface irrigation and new high water‐saving technologies have both been present. Despite these two kinds of irrigation technologies, it is difficult to realize the effect of water saving and increasing production using the former, which is an engineering water‐saving mode using a canal anti‐seepage technique. To some degree, it inhibits ecological water use. The latter, which is an agronomic water‐saving mode laying emphasis on crop growth mechanisms, can realize the effect of water saving and increasing production. But, on the other hand, it is unable to improve soil characteristics. On the contrary, it might even aggravate soil salinization. Therefore, both engineering water saving and agronomic water saving must reconsider the sustainability of water saving. Can it realize reasonable water resources allocation of the whole watershed? Can it realize sustainable utilization of water resources in the whole watershed? This paper advances a new concept of modern agricultural water saving – sustainable water saving – which is different from real water saving. Copyright © 2008 John Wiley & Sons, Ltd.
Antitumor properties of a sulfated polysaccharide from the red seaweed Champia feldmannii (Diaz‐Pifferer)
Authors: Lins Kézia O. A. L. , Bezerra Daniel P. , Alves Ana Paula N. N. , Alencar Nylane M. N. , Lima Michael W. , Torres Valeska M. , Farias Wladimir R. L. , Pessoa Cláudia , de Moraes Manoel O. , Costa‐Lotufo Letícia V.
Published: July 2008

In recent years, much attention has been focused on polysaccharides isolated from natural sources. The aim of this study was to investigate the in vitro and in vivo antitumor properties of a sulfated polysaccharide isolated from the seaweed C. feldmannii (Cf‐PLS). Hematological, biochemical and histopathological analyses were performed in order to evaluate the toxicological aspects related to Cf‐PLS treatment. Its effects on the immunological system were also investigated. The Cf‐PLS did not show any significant in vitro cytotoxicity at the experimental exposure levels that were used, but showed in vivo antitumor effect. The inhibition rates of sarcoma 180 tumor development were 48.62 and 48.16% at the doses of 10 and 25 mg kg−1, respectively. In addition, Cf‐PLS was also able to increase the response elicited by 5‐fluorouracil (5‐FU) from 48.66 to 68.32%. The histopathological analysis of liver and kidney showed that both organs were moderately affected by Cf‐PLS‐treatment. Neither enzymatic activity of alanine aminotransferase nor urea or creatinine levels were significantly altered. In hematological analysis, leucopeny was observed after 5‐FU treatment, but this effect was prevented when the treatment was associated with the Cf‐PLS. It was also demonstrated that Cf‐PLS acts as an immunomodulatory agent, raising the production of specific antibodies, and increasing the production of OVA‐specific antibodies. It also induced a discreet hyperplasia of lymphoid folicules of the white pulp in the spleen of treated mice. In conclusion, Cf‐PLS has some interesting anticancer activity that could be associated with its immunostimulating properties. Copyright © 2008 John Wiley & Sons, Ltd.
Biomimetic scaffolds fabricated from apatite‐coated polymer microspheres
Authors: Davis Hillary E. , Rao Rameshwar R. , He Jiawei , Leach J. Kent
Published: July 2008

The deposition of a bonelike mineral on the surface of polymer scaffolds results in the formation of hybrid biomaterials, possessing enhanced osteoconductivity while retaining appropriate biodegradability. However, current methods of fabricating such composite scaffolds use a prolonged incubation process, which permits scaffold deformation and premature loss of incorporated macromolecules. We hypothesized that the fabrication of biomineralized polymer scaffolds could be achieved using premineralized polymer microspheres generated through incubation in a modified simulated body fluid (mSBF). We explored the material characteristics of these substrates and characterized the in vitro osteogenic differentiation of human mesenchymal stem cells (hMSCs) when cultured on these novel scaffolds. Unlike scaffolds prepared using the conventional approach, premineralized scaffolds maintained their initial conformation after fabrication, achieved improved mineral distribution throughout the substrate, and enabled significantly greater incorporation efficiency of a model protein. We did not detect differences in osteogenic differentiation as determined by alkaline phosphatase activity and osteopontin secretion. However, we did observe a significant increase in cell‐secreted calcium by hMSCs seeded on scaffolds prepared from premineralized polymer. These results demonstrate that the use of premineralized polymeric materials to fabricate biodegradable polymer scaffolds is an improved method for composite scaffold formation and may have numerous advantages for use in bone tissue engineering. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Identification of long range regulatory elements of mouse α‐globin gene cluster by quantitative associated chromatin trap (QACT)
Authors: Di Li‐Jun , Wang Li , Zhou Guo‐ling , Wu Xue‐song , Guo Zhi‐chen , Ke Xi‐song , Liu De‐pei , Liang Chih‐chuan
Published: July 2008

Chromatin from different regions of the genome frequently forms steady associations that play important roles in regulating gene expression. The widely used chromatin conformation capture (3C) assay allows determination of the in vivo structural organization of an active endogenous locus. However, unpredicted chromatin associations within a given genomic locus can not be identified by 3C. Here, we describe a new strategy, quantitative associated chromatin trap (QACT), which incorporates a modified 3C method and a quantitative assay tool, to capture and quantitatively analyzes all possible associated chromatin partners (ACPs) of a given chromatin fragment. Using QACT, we have analyzed the chromatin conformation of the mouse α‐globin gene cluster and proved the extensive interaction between HS26 and α‐globin genes. In addition, we have identified a candidate α1‐globin gene specific silencer 475A8 which shows the differentiation‐stage specific DNase I hypersensitivity. Functional analysis suggests that 475A8 may regulate the α1‐globin gene during terminal differentiation of committed erythroid progenitor cells. ChIP (chromatin immunoprecipitation) and cotransfection assays demonstrate that GATA‐1, a hemopoietic specific transcriptional factor, may increase α1‐globin gene expression by suppressing the function of 475A8 in terminally differentiated erythroid cells. J. Cell. Biochem. 105: 301–312, 2008. © 2008 Wiley‐Liss, Inc.
Microgenomics profile the endogenous angiogenic phenotype in subpopulations of aggressive Melanoma
Authors: Demou Zoe N. , Hendrix Mary J.C.
Published: July 2008

Beyond the elemental role of blood vessels in tumor growth, fluid conducting networks lacking endothelium (termed vasculogenic mimicry) were identified previously in metastatic melanoma and other cancer types. The etiology remains unclear, though it appears to involve dysregulation of the tumor‐specific phenotype and transdifferentiation. Instigating the molecular deciphering of this phenomenon, we established a novel technique for microdissecting the spontaneously formed vascular‐like networks and the randomly arranged cells (nests) from living 3D cultures of melanoma and performed microgenomics analysis. For the first time we show that despite the shared genotype, transcription was differentially regulated among the phenotypically distinct melanoma structures in vasculogenic mimicry. Several angiogenesis‐specific genes were differentially expressed in higher levels in network cells of both uveal and cutaneous melanoma with intriguing representation of the ephrin family of angiogenesis factors, which was confirmed with immunocytochemistry. Interestingly, the adjacent nest‐cells over‐expressed ECM‐related genes. Moreover, expression of angiogenesis‐specific genes in melanoma resembled that of normal microvascular cells and was enhanced in melanoma disseminating hematogenously. The findings suggest that melanoma plasticity could enable autopoiesis of vascular‐mimicking elements within the tumor infrastructure with significant clinical implications, such as response to anti‐angiogenic treatments. Identifying factors regulating tumor plasticity and heterogeneity at the molecular level is essential in designing effective anti‐cancer therapies. J. Cell. Biochem. 105: 562–573, 2008. © 2008 Wiley‐Liss, Inc.
Histones and nucleosomes in Cancer sperm (Decapod: Crustacea) previously described as lacking basic DNA‐associated proteins: A new model of sperm chromatin
Authors: Kurtz Kathryn , Martínez‐Soler Fina , Ausió Juan , Chiva Manel
Published: July 2008

To date several studies have been carried out which indicate that DNA of crustacean sperm is neither bound nor organized by basic proteins and, contrary to the rest of spermatozoa, do not contain highly packaged chromatin. Since this is the only known case of this type among metazoan cells, we have re‐examined the composition, and partially the structure, of the mature sperm chromatin of Cancer pagurus, which has previously been described as lacking basic DNA‐associated proteins. The results we present here show that: (a) sperm DNA of C. pagurus is bound by histones forming nucleosomes of 170 base pairs, (b) the ratio [histones/DNA] in sperm of two Cancer species is 0.5 and 0.6 (w/w). This ratio is quite lower than the proportion [proteins/DNA] that we found in other sperm nuclei with histones or protamines, whose value is from 1.0 to 1.2 (w/w), (c) histone H4 is highly acetylated in mature sperm chromatin of C. pagurus. Other histones (H3 and H2B) are also acetylated, though the level is much lower than that of histone H4. The low ratio of histones to DNA, along with the high level of acetylation of these proteins, explains the non‐compact, decondensed state of the peculiar chromatin in the sperm studied here. In the final section we offer an explanation for the necessity of such decondensed chromatin during gamete fertilization of this species. J. Cell. Biochem. 105: 574–584, 2008. © 2008 Wiley‐Liss, Inc.
Vitamin D and multiple sclerosis
Authors: Raghuwanshi Anita , Joshi Sneha S. , Christakos Sylvia
Published: July 2008

Vitamin D is a principal regulator of calcium homeostasis. However, recent evidence has indicated that vitamin D can have numerous other physiological functions including inhibition of proliferation of a number of malignant cells including breast and prostate cancer cells and protection against certain immune mediated disorders including multiple sclerosis (MS). The geographic incidence of MS indicates an increase in MS with a decrease in sunlight exposure. Since vitamin D is produced in the skin by solar or UV irradiation and high serum levels of 25‐hydroxyvitamin D (25(OH)D) have been reported to correlate with a reduced risk of MS, a protective role of vitamin D is suggested. Mechanisms whereby the active form of vitamin D, 1,25‐dihydroxyvitamin D3 (1,25(OH)2D3) may act to mediate this protective effect are reviewed. Due to its immunosuppressive actions, it has been suggested that 1,25(OH)2D3 may prevent the induction of MS. J. Cell. Biochem. 105: 338–343, 2008. © 2008 Wiley‐Liss, Inc.
Quercetin‐induced ubiquitination and down‐regulation of Her‐2/neu
Authors: Jeong Jae‐Hoon , An Jee Young , Kwon Yong Tae , Li Lu‐Yuan , Lee Yong J.
Published: July 2008

Her‐2/neu (ErbB2) is a transmembrane tyrosine kinase and acts as a co‐receptor for the other EGFR family members. It is well known that high expression of Her‐2/neu is associated with a poor prognosis in breast cancer. Quercetin, a flavonoid present in many vegetables and fruits, has been studied extensively as a chemoprevention agent in several cancer models. In this study, we observed that quercetin decreased the level of Her‐2/neu protein in time‐ and dose‐dependent manners and also inhibited the downstream survival PI3K‐Akt signaling pathway in Her‐2/neu‐overexpressing breast cancer SK‐Br3 cells. We also observed that quercetin induced polyubiquitination of Her‐2/neu. When the proteasome pathway was blocked by MG‐132 during quercetin treatment, accumulation of the NP‐40 insoluble form of Her‐2/neu occurred. Interestingly, data from immunocomplex studies revealed that quercetin promoted interaction between Her‐2/neu and Hsp90 which is a molecular chaperone involved in stabilization of Her‐2/neu. In this condition, inhibition of Hsp90 activity by a specific inhibitor, geldanamycin (GA), or intracellular ATP depletion caused dissociation of Hsp90 from Her‐2/neu and promoted ubiquitination and down‐regulation of Her‐2/neu protein. In addition, the carboxyl terminus of Hsc70‐interacting protein (CHIP), a chaperone‐dependent E3 ubiquitin ligase, played a crucial role in the quercetin‐induced ubiquitination of Her‐2/neu. Inhibition of tyrosine kinase activity of Her‐2/neu by quercetin could indicate an lateration in the Her‐2/neu structure which promotes CHIP recruitments and down‐regulation of Her‐2/neu. We believe that by using quercetin, new therapeutic strategies can be developed to treat Her‐2/neu overexpressing cancers. J. Cell. Biochem. 105: 585–595, 2008. © 2008 Wiley‐Liss, Inc.
IFN‐γ synergizes with LPS to induce nitric oxide biosynthesis through glycogen synthase kinase‐3‐inhibited IL‐10
Authors: Lin Chiou‐Feng , Tsai Cheng‐Chieh , Huang Wei‐Ching , Wang Chi‐Yun , Tseng Hsiang‐Chi , Wang Yi , Kai Jui‐In , Wang Szu‐Wen , Cheng Yi‐Lin
Published: July 2008

Interferon‐γ (IFN‐γ) plays a crucial role in innate immunity and inflammation. It causes the synergistic effect on endotoxin lipopolysaccharide (LPS)‐stimulated inducible nitric oxide synthase (iNOS)/NO biosynthesis; however, the mechanism remains unclear. In the present study, we investigated the effects of glycogen synthase kinase‐3 (GSK‐3)‐mediated inhibition of anti‐inflammatory interleukin‐10 (IL‐10). We found, in LPS‐stimulated macrophages, that IFN‐γ increased iNOS expression and NO production in a time‐dependent manner. In addition, ELISA analysis showed the upregulation of tumor necrosis factor‐α and regulated on activation, normal T expressed and secreted, and the downregulation of IL‐10. RT‐PCR further showed changes in the IL‐10 mRNA level as well. Treating cells with recombinant IL‐10 showed a decrease in IFN‐γ/LPS‐induced iNOS/NO biosynthesis, whereas anti‐IL‐10 neutralizing antibodies enhanced this effect, suggesting that IL‐10 acts in an anti‐inflammatory role. GSK‐3‐inhibitor treatment blocked IFN‐γ/LPS‐induced iNOS/NO biosynthesis but upregulated IL‐10 production. Inhibiting GSK‐3 using short‐interference RNA showed similar results. Additionally, treating cells with anti‐IL‐10 neutralizing antibodies blocked these effects. We further showed that inhibiting GSK‐3 increased phosphorylation of transcription factor cyclic AMP response element binding protein. Inhibiting protein tyrosine kinase Pyk2, an upstream regulator of GSK‐3β, caused inhibition on IFN‐γ/LPS‐induced GSK‐3β phosphorylation at tyrosine 216 and iNOS/NO biosynthesis. Taken together, these findings reveal the involvement of GSK‐3‐inhibited IL‐10 on the induction of iNOS/NO biosynthesis by IFN‐γ synergized with LPS. J. Cell. Biochem. 105: 746–755, 2008. © 2008 Wiley‐Liss, Inc.