bluuebunny/crossref_metadata_2025_split huggingface dataset:
Genetic variants in protein kinase C zeta gene and type 2 diabetes risk: a case‐control study of a Chinese Han population
Authors: Qin Lei , Zhou Ling , Wu Xueji , Cheng Jinluo , Wang Jingsong , Du Yunfeng , Hu Jihong , Shen Moyu , Zhou Jinyi 
Published: July 2008

AbstractBackgroundPrevious investigations of the protein kinase C zeta (PRKCZ) gene, a susceptibility factor for type 2 diabetes mellitus (T2DM), have focussed on its single nucleotide polymorphisms (SNPs). In a departure from these earlier studies, we tested six tagging markers of PRKCZ based on the Hapmap database to evaluate their association with T2DM.MethodsPCR‐RFLP was performed to test the genotypes in type 2 diabetes patients (n = 343) and normal controls (n = 429). Insulin‐related indexes were calculated from levels of fasting plasma insulin (FPI) and fasting plasma glucose (FPG).ResultsThe variant genotypes, rs3753242TT, rs2503706CT, rs2503706CT/ TT and rs262654TT were associated with T2DM. And the significance remained for rs3753242 TT (p < 0.001) after the false discovery rate (FDR) correction. There was a doubling in the prevalence of the TTGCCC haplotype in the case subjects (14.2%) compared with the control subjects (6.9%) [OR (95% CI) = 2.19(1.49–3.22)]. In the control group, none of the haplotypes studied was associated with insulin‐related indexes.ConclusionsThe PRKCZ gene variants associated with the development of T2DM in this study must be investigated in a larger population to reveal any potential effects on metabolism. Copyright © 2008 John Wiley & Sons, Ltd.
Globular adiponectin stimulates glucose transport in type 2 diabetic muscle
Authors: Kuoppamaa Heidi , Skrobuk Paulina , Sihvo Maarit , Hiukka Anne , Chibalin Alexander V. , Zierath Juleen R. , Koistinen Heikki A. 
Published: July 2008

AbstractBackgroundAdiponectin acts as an insulin sensitizer in rodent models. The direct effect of adiponectin in intact type 2 diabetic muscle is unknown. We examined whether adiponectin stimulates glucose transport in isolated skeletal muscle strips from type 2 diabetic men.MethodsWe obtained open muscle biopsies from 12 men with type 2 diabetes (56 ± 1 years, 30.5 ± 1.1 kg/m2), and from 15 non‐diabetic men (59 ± 1 years, 28.0 ± 1.0 kg/m2). Skeletal muscle strips were isolated and exposed to globular adiponectin (2.5 µg/mL), insulin (120 nM) and/or AICAR (1 mM) in vitro for 1 h. Glucose transport was analysed by accumulation of intracellular 3‐O‐methyl [3H] glucose, phosphorylation of Akt‐Ser473 and Akt‐Thr308 was determined using phosphospecific antibodies, and adiponectin receptor 1 and 2 content was measured using specific antibodies.ResultsGlobular adiponectin increased glucose transport rate by 1.3‐fold (P < 0.01) in type 2 diabetic, but not in non‐diabetic muscle. Insulin‐stimulated glucose transport rate was unaltered by exposure to globular adiponectin in either group. AICAR increased glucose transport and enhanced insulin‐stimulated glucose transport in type 2 diabetic and non‐diabetic muscles. Insulin‐stimulated phosphorylation of Akt‐Ser473 or Akt‐Thr308 was comparable in type 2 diabetic and non‐diabetic muscles, and unaltered by the addition of globular adiponectin in either group. Adiponectin receptor expression was similar in skeletal muscle from type 2 diabetic and non‐diabetic men.ConclusionsGlobular adiponectin directly increases glucose transport in skeletal muscle from type 2 diabetic patients. This may occur via Akt‐independent signalling routes. Copyright © 2008 John Wiley & Sons, Ltd.
Two Hexanickel‐Substituted Keggin‐Type Germanotungstates
Authors: Zhao Jun‐Wei , Zhang Jie , Song You , Zheng Shou‐Tian , Yang Guo‐Yu 
Published: July 2008

AbstractTwo new inorganic–organic hybrid germanotungstates built from trivacant Keggin fragments and in situ generated hexanickel clusters [Ni(en)2]0.5[{Ni6(μ3‐OH)3(en)3(H2O)6}(B‐α‐GeW9O34)]·3H2O (1) and [{Ni6(μ3‐OH)3(dap)3(H2O)6}(B‐α‐GeW9O34)]·H3O·4H2O (2) (en = ethylenediamine and dap = 1,2‐diaminopropane) were hydrothermally synthesized and characterized by IR spectroscopy, elemental analysis, thermogravimetric analysis, single‐crystal X‐ray diffraction and magnetic analysis. Compound 1 crystallizes in the monoclinic space group P21/n; whereas compound 2 crystallizes in the monoclinic space group P21/c. Single‐crystal X‐ray diffraction indicates that both contain a hexa‐NiII‐substituted trivacant Keggin unit [{Ni6(μ3‐OH)3(L)3(H2O)6}(B‐α‐GeW9O34)]– (L = en or dap). Magnetic susceptibility measurements show the presence of ferromagnetic coupling interactions within the hexa‐NiII clusters for 1 and 2. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Metal‐Ion‐Mediated Base Pairs in Nucleic Acids
Authors: Müller Jens 
Published: July 2008

AbstractNucleic acids and their analogues raise more and more interest in research areas outside biology and biochemistry. The functionalization of these evolutionary optimized self‐assembling macromolecules with metal ions widens their applicability even further. Previous efforts to incorporate metal ions site‐specifically into nucleic acids focused on the covalent attachment of appropriate ligands to either the sugar phosphate backbone or the nucleobases. More recently, the use of metal‐ion‐mediated base pairs, i.e. the replacement of natural nucleobases by ligands, was suggested as an alternative means. This microreview discusses selected examples of metal‐ion‐mediated base pairs, including those that comprise unmodified natural nucleobases, and describes possible applications for the resulting metal‐modified nucleic acids. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Lanthanide Complexes and Quantum Dots: A Bright Wedding for Resonance Energy Transfer (Eur. J. Inorg. Chem. 21/2008)
Authors: Charbonnière Loïc J. , Hildebrandt Niko 
Published: July 2008

AbstractThe cover picture shows the schematic realization of a homogeneous fluoroimmunoassay using Förster resonance energy transfer (FRET) from luminescent lanthanide complexes (LLCs – an example of a Tb complex is shown in the top right corner) to a biocompatible CdSe/ZnS quantum dot (QD). Excitation of the immunocomplex formed by the association of QD‐labeled antibodies, antigen and LLC‐labeled antibodies by UV light (e.g. 315 nm) leads to a long‐lived Tb and QD luminescence (luminescence spectra shown in the bottom right corner) due to FRET sensitization by the LLCs. This new immunoassay approach opens doors to extremely sensitive background‐free fluoroimmunoassays suitable for multiplexing by using several different QDs as FRET acceptors with a single LLC donor. Details are discussed in the Microreview by L. J. Charbonnière and N. Hildebrandt on p. 3241 ff.
Regioselective Three‐Component Synthesis of Highly Fluorescent 1,3,5‐Trisubstituted Pyrazoles
Authors: Willy Benjamin , Müller Thomas J. J. 
Published: July 2008

Abstract3,5‐Disubstituted and 1,3,5‐trisubstituted pyrazoles are readily synthesized from acyl chlorides, terminal alkynes, and hydrazines by a consecutive one‐pot three‐component Sonogashira coupling/Michael addition/cyclocondensation sequence in good to excellent yields. These pyrazoles are highly fluorescent, both in solution and in the solid state. Investigation of the electronic properties by UV/Vis and fluorescence spectroscopy and by DFT and ZINDO CI computations reveal that the excited state is highly polar and allows fine‐tuning of the absorption and emission properties. X‐ray structure analyses of 3,5‐disubstituted pyrazoles reveal self‐organization by hydrogen bonding and π‐stacking. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Field‐Effect Nanoparticle‐Based Glucose Sensor on a Chip: Amplification Effect of Coimmobilized Redox Species
Authors: Gun Jenny , Schöning Michael J. , Abouzar Maryam H. , Poghossian Arshak , Katz Evgeny 
Published: July 2008

AbstractA capacitive EIS (electrolyte‐insulator‐semiconductor) structure was modified with gold nanoparticles together with glucose oxidase and used as field‐effect‐based glucose biosensor using the constant capacitance mode. Co‐immobilization of ferrocene redox species resulted in a two‐fold increase of the biosensor sensitivity. The effect was explained by the hydrogen peroxide‐mediated oxidation of ferrocene resulting in a pool of charged species at the interface increasing the sensor response towards glucose. The studied approach was suggested as a general means to amplify signals from Si chip‐based field‐effect enzyme biosensors.
Direct Electrochemistry and Electrocatalysis of Myoglobin Immobilized on Gold Nanoparticles/Carbon Nanotubes Nanohybrid Film
Authors: Cao Wei , Wei Cuimei , Hu Jingbo , Li Qilong 
Published: July 2008

AbstractA novel nanohybrid material, constructed by gold nanoparticles (GNPs) and multiwalled carbon nanotubes (MWNTs), was designed for immobilization and biosensing of myoglobin (Mb). Morphology of the nanohybrid film was characterized by SEM. UV‐vis spectroscopy demonstrated that Mb on the composite film could retain its native structure. Direct electrochemistry of Mb immobilized on the GNPs/MWNTs film was investigated. The immobilized Mb showed a couple of quasireversible and well‐defined cyclic voltammetry peaks with a formal potential of about −0.35 V (vs. Ag/AgCl) in pH 6.0 phosphate buffer solution (PBS) solution. Furthermore, the modified electrode also displayed good sensitivity, wide linear range and long‐term stability to the detection of hydrogen peroxide. The experiment results demonstrated that the hybrid matrix provided a biocompatible microenvironment for protein and supplied a necessary pathway for its direct electron transfer.
Calculation of the isoelectric point of tryptic peptides in the pH 3.5–4.5 range based on adjacent amino acid effects
Authors: Cargile Benjamin J. , Sevinsky Joel R. , Essader Amal S. , Eu Jerry P. , Stephenson James L. 
Published: July 2008

AbstractCurrent algorithms for the calculation of peptide or protein pI, based on the charge associated with individual amino acids, can calculate pI values to within ±0.2 pI units. Here, we present a new pI calculation algorithm that takes into account the effect of adjacent amino acids on the pI value. The algorithm accounts for the effect of adjacent amino acids ± 3 residues away from a charged aspartic or glutamic acid, as well as effects on the free C terminus, and applies a correction term to the corresponding pK values. The correction increments are derived from a 5000‐peptide training set using a genetic optimization approach. The accuracy of the new pI values obtained with this method approaches the error associated with the manufacture of the IPG strip (<±0.03 pI units). The approach is demonstrated for cytosolic cell extracts derived from the breast‐cancer cell line DU4475, and from membrane preparations from human lung‐tissue samples. One potential application of a more highly accurate pI calculation is data filtering of MS/MS outputs that will allow for more complex database searches including gene finding, and validation, and detection of coding single‐nucleotide polymorphisms in their expressed form.
Surface modification of polymer microfluidic devices using in‐channel atom transfer radical polymerization
Authors: Sun Xuefei , Liu Jikun , Lee Milton L. 
Published: July 2008

AbstractIn‐channel atom transfer radical polymerization (ATRP) was used to graft a PEG layer on the surface of microchannels formed in poly(glycidyl methacrylate)‐co‐(methyl methacrylate) (PGMAMMA) microfluidic devices. The patterned and cover plates were first anchored with ATRP initiator and then thermally bonded together, followed by pumping a solution containing monomer, catalyst, and ligand into the channel to perform ATRP. A PEG‐functionalized layer was grafted on the microchannel wall, which resists protein adsorption. X‐ray photoelectron spectroscopy (XPS) was used to investigate the initiator‐bound surface, and EOF was measured to evaluate the PEG‐grafted PGMAMMA microchannel. Fast, efficient, and reproducible separations of amino acids, peptides, and proteins were obtained using the resultant microdevices. Separation efficiencies were higher than 1.0×104 plates for a 3.5 cm separation microchannel. Compared with microdevices modified using a previously reported ATRP technique, these in‐channel modified microdevices demonstrated better long‐term stability.
Use of quasi‐isoelectric buffers to limit protein adsorption in capillary zone electrophoresis
Authors: Poitevin Martine , Hammad Karim , Ayed Ichraf , Righetti Pier Giorgio , Peltre Gabriel , Descroix Stephanie 
Published: July 2008

AbstractThe use of quasi‐isoelectric buffers consisting of narrow pH cuts of carrier ampholytes (NC) has been investigated to limit protein adsorption on capillary walls during capillary zone electrophoresis experiments. To quantify protein adsorption on the silica surface, a method derived from that of Towns and Regnier has been developed. α‐Lactalbumin (14 kDa, pI 4.8) and α–chymotrypsinogen A (25 kDa, pI 9.2) have been used as model proteins. Acidic narrow pH cuts of carrier ampholytes (NC, pH 3.0) obtained from fractionation of Serva 4‐9 carrier ampholytes were used as BGE in bare‐silica capillaries, and allowed to decrease significantly protein adsorption, as compared to experiments performed with classical formate buffer. The use of NC as BGE appeared to be as efficient as the use of polydimethylacrylamide coating to prevent protein adsorption. This increase of protein recovery when using NC was attributed to the interaction of carrier ampholytes with the silica surface, leading to a shielding of the capillary wall.
Preparation of a PET‐Hydrolyzing Lipase fromAspergillus oryzaeby the Addition of Bis(2‐hydroxyethyl) Terephthalate to the Culture Medium and Enzymatic Modification of PET Fabrics
Authors: Wang X. , Lu D. , Jönsson L. J. , Hong F. 
Published: July 2008

AbstractOptimization of cultivation conditions for lipase production and the preparation of a specific lipase catalyzing the hydrolysis of polyethylene terephthalate (PET) by Aspergillus oryzae CCUG 33812 as well as modification of PET fabrics by the enzyme were investigated. The lipase activity produced by the fungus after the addition of olive oil was not efficient in changing the properties of PET samples. In order to obtain lipase activity directed toward the hydrolysis of PET, two derivatives of terephthalic acid (TPA), namely diethyl p‐phthalate (DP) and bis(2‐hydroxyethyl) terephthalate (BHT), and PET short fibers were used as inducers. The results showed that BHT was the best inducer. The BHT‐induced extracellular lipase could catalyze the hydrolysis of the PET model substrate DP. The formation of new carboxyl groups is consistent with the increase in K/S values of dyed PET fabrics after the enzymatic treatment. Additionally, treatment with the BHT‐induced lipase resulted in increased moisture regain and weight loss of PET fiber/fabric, while the water contact angle and the static half decay time decreased slightly. This indicates that hydrophilicity and anti‐static ability were improved after the treatment with the BHT‐induced lipase. Compounds that were solubilized by the enzymatic treatment were analyzed by spectrophotometry and high performance liquid chromatography (HPLC) with UV detection. Both analyses indicated that hydrolysis of PET occurred and that products were formed due to the catalytic action of the BHT‐induced enzyme; however, no significant changes in UV absorbance and no new peaks were found in HPLC‐UVD analyses of reaction mixtures with olive oil‐induced lipase or PET‐induced lipase. This investigation has resulted in detailed procedures for the production of PET‐hydrolyzing lipase by A. oryzae and is the first report regarding the successful use of BHT as an inducer for the enzyme production.
Stabilization of Membrane Proteins: the Case of G‐Protein‐Coupled Receptors
Authors: Reyes‐Alcaraz A. , Tzanov T. , Garriga P. 
Published: July 2008

AbstractG‐protein‐coupled receptors are integral membrane proteins which constitute the largest family of signal transduction molecules participating in the majority of normal physiological processes. G‐protein‐coupled receptors are responsible for the control of enzyme activity, ion channels and vesicle transport, and they respond to a wide variety of stimuli, like signals involved in sensory systems such as vision, taste and olfaction, but also to a diverse set of chemical signals such as lipids, hormones, neurotransmitters, amino acids, nucleotides, peptides and proteins. This family of receptors is being widely studied because of its potential use as pharmacological targets in drug development, and recently also for its potential use in the development of novel biosensors. G‐protein‐coupled receptors are specifically designed to fold and function in a lipid bilayer environment, where these membrane proteins are remarkably stable and achieve their optimal performance. The currently used technology for the purification of G‐protein‐coupled receptors consists in their extraction from the cell membrane and solubilization into detergent micelles. A common drawback of this strategy is that G‐protein‐coupled receptors solubilized in typical detergents show rather poor conformational stability, which may result in relatively rapid inactivation. The poor stability of detergent‐solubilized samples renders many membrane proteins biochemically intractable. This precludes the determination of a high‐resolution structure and imposes severe limitations for the development of applications. Thus, the enhancement of the stability of G‐protein‐coupled receptors is a major issue in order to facilitate structural determination and to unravel their potential in biotechnological applications. This work provides a brief overview of some current advances in the experimental methods for stabilizing G‐protein‐coupled receptors that can also be extended to other types of membrane proteins.
In‐situ Enzymatic Generation of Hydrogen Peroxide for Bleaching Purposes
Authors: López C. , Cavaco‐Paulo A. 
Published: July 2008

AbstractBleaching detergent formulations contain environmentally unfriendly bleaching agents (perborates and percarbonates), which cause aquatic eutrophication, although without these compounds detergents are much less efficient for the washing processes. In an effort to replace these compounds, in this study, hydrogen peroxide was generated as a bleaching compound by means of enzymatic reactions. Three different pathways were investigated. The first one was the H2O2 production from glucose by glucose oxidase. The second one was the production of H2O2 from carboxymethylcellulose (CMC) by the action of both cellulase, which promotes the hydrolysis of the polymeric chain, and glucose oxidase, which oxidizes the smaller fractions to produce H2O2. Finally, H2O2 was also obtained from ethanol, which is present in liquid detergents, by the action of the enzyme alcohol oxidase. In the search for maximal peroxide production, substrate concentration and enzymatic activities were optimized. The effect of H2O2 produced in the washing process was simulated by means of a process of cotton bleaching. Although enzymatic‐reaction oxidations produced higher levels of hydrogen peroxide (up to 1 g/L after 8 h), higher improvement of cotton whiteness was achieved from CMC and from ethanol. The milder conditions of temperature and pH, biodegradability and less consumption of water and energy are advantageous for enzymes as good substitutes for H2O2 precursors and make them appropriate to be considered in detergent formulations. These enzymes could be combined with other oxidative enzymes, such as peroxidases, in order to lower the required temperature and use a pH close to the neutral value during the bleaching processes.
Biological Coloration of Flax Fabrics with Flavonoids using Laccase fromTrametes hirsuta
Authors: Kim S. , López C. , Güebitz G. , Cavaco‐Paulo A. 
Published: July 2008

AbstractBiological environmentally friendly concepts are emerging to replace chemical treatments of fabrics. In this work, a new process for the coloration of flax fabrics via enzymatic oxidation of natural flavonoids (morin, quercetin) has been developed. Laccase fromTrametes hirsutais able to react with flavonoids and polymerize them, resulting in a strongly colored polymeric solution which can be applied to the coloration of flax fabrics. Two methods were investigated:(i)the simultaneous enzymatic polymerization and coloration of fabrics and(ii)the polymerization of flavonoids with laccase, followed by a further coloration of the flax fabrics. Factors such as temperature, reaction time, presence of NaCl or the use of bleached or unbleached fabrics were evaluated in order to increase the color of the fabrics and the color fastness. The increase of temperature, the presence of salt and the use of unbleached fabrics allowed the final color to be improved. Colorized flax fabrics with oxidized quercetin solution showed a color fixation two times higher than the fabrics colorized with oxidized morin. Finally, the polymerization of flavonoids and their binding to fibers were verified using Fourier transform infrared spectroscopy (FT‐IR). The results confirmed this environmentally friendly process as useful for the coloration of flax fabrics. A similar technique could also be extended to the treatment of other types of fabrics in textile processes.
Potential Applications of Oxidoreductases for the Re‐oxidation of Leuco Vat or Sulfur Dyes in Textile Dyeing
Authors: Xu F. , Salmon S. 
Published: July 2008

AbstractConventional textile dyeing by vat and sulfur dyes includes reduction and re‐oxidation steps (with chemical reductants and oxidants), so that the insoluble dyes can be solubilized in the dyeing solution, adsorbed by the fabric, and fixed onto the dyed fabric. The treatments often involve hazardous chemicals, expensive catalysts, or conditions that are suboptimally effective, energy‐intensive, caustic, or polluting. Improving these steps with enzyme technology could be of significant interest in terms of better dyeing, handling of hazardous chemicals, disposal of waste, or production economy. The idea of an enzymatic re‐oxidation step for vat and sulfur dyeings was tested under simplified laboratory conditions. Selected vat and sulfur dyes, including Vat Blue 43, Vat Orange 7, Vat Green 3, Vat Orange 2, Vat Red 13, Vat Yellow 2, and Sulfur Black 1, were first chemically reduced. The reduced (leuco) dyes were then re‐oxidized by aerated buffer solutions or H2O2, in the presence or absence of an oxidoreductase, selected from seven laccases from Myceliophthora thermophila, Scytalidium thermophilum, Coprinus cinereus, Trametes villosa, Rhizoctonia solani, Pycnoporus cinnabarinus, Botrytis cinerea, a bilirubin oxidase from Myrothecium verrucaria, and a heme peroxidase from Coprinus cineresu. It was shown that the enzymes were able to catalyze and accelerate the re‐oxidation of the reduced dyes, even when they were adsorbed on cotton fabric, by dissolved air (O2) or H2O2. Small redox‐active mediators could facilitate the enzymatic re‐oxidation. For Sulfur Black 1, a higher conversion of the leuco dye was achieved with laccase‐catalyzed re‐oxidation. The further development of this potential enzyme application is discussed.