bluuebunny/crossref_metadata_2025_split huggingface dataset:
High‐rate ferric sulfate generation by a Leptospirillum ferriphilum‐dominated biofilm and the role of jarosite in biomass retainment in a fluidized‐bed reactor
Authors: Kinnunen Päivi H.‐M. , Puhakka Jaakko A. 
Published: February 2004

AbstractThe aims of this work were to develop a high‐rate fluidized‐bed bioprocess for ferric sulfate production, to characterize biomass retainment, and to determine the phylogeny of the enrichment culture. After 7 months of continuous enrichment and air aeration at 37°C, the iron oxidation rate of 8.2 g Fe2+ L−1h−1 (4.5·10−12 g Fe2+ cell‐1 h−1) was obtained at a hydraulic retention time (HRT) of 0.6 h. However, oxygen supply became the rate‐limiting factor. With gas mixture (99.5% O2/0.5% CO2 (vol/vol)) aeration and HRT of 0.2 h, the iron oxidation rate was 26.4 g Fe2+ L−1h−1 (1.0·10−11 g Fe2+ cell−1 h−1). Leptospirillum sp. was predominant in the mesophilic fluidized‐bed reactor (FBR) enrichment culture as determined by fluorescent in situ hybridization, while Acidithiobacillus ferrooxidans was not detected. Denaturing gradient gel electrophoresis (DGGE) of the amplified partial 16S rDNA showed only three bands, indicating a simple microbial community. DGGE fragment excision and sequencing showed that the populations were related to L. ferriphilum (100% similarity in sequence) and possibly to the genus Ferroplasma (96% similarity to F. acidiphilum). Jarosite precipitates accumulated on the top of the activated carbon biomass carrier material, increasing the rate of iron oxidation. The activated carbon carrier material, jarosite precipitates, and reactor liquid contained 59% (or 3.71·109 cells g−1), 31% (or 3.12·1010 cells g−1) and 10% (or 1.24·108 cells mL−1) of the total FBR microbes, respectively, demonstrating that the jarosite precipitates played an important role in the FBR biomass retainment. © 2004 Wiley Periodicals, Inc.
Optimization of reovirus production from mouse L‐929 cells in suspension culture
Authors: Jung Sunghoon , Behie Leo A. , Lee Patrick W. K. , Farrell Patrick J. 
Published: February 2004

AbstractReovirus serotype 3 Dearing (T3D) has shown potential as a novel cancer therapy. To support the increasing demand for reovirus, a two‐stage perfusion mode scheme is proposed for cell growth and reovirus production. Mouse L‐929 cells were used as the host for reovirus infection due to their ability to grow well in suspension culture. Several L‐929 cell growth and reovirus infection characteristics were investigated and optimized in spinner flask batch cultures. For the growth of L‐929 cells, a balanced nutrient‐fortification of SMEM medium increased the maximum cell density by 30%, compared to normal SMEM; however, ammonia and lactate accumulations were found to inhibit further cell growth. For the production of reovirus, ∼90% increase in viral yield resulted when the infection temperature was reduced from 37 to 33°C. Infectious reovirus particles were shown to be stable in conditioned medium at 37 and 33°C. The final virus titer was dependent on the multiplicity of infection (MOI) and the host cell density at the time of infection. A combination of an MOI of 0.1 pfu/cell and an initial host cell density of 1.0 × 106 cells/mL in fortified medium resulted in a maximum virus titer of (4.59 ± 0.16) × 109 pfu/mL and a specific yield of (2.34 ± 0.08) × 103 pfu/cell. At an optimal harvest time of the infection process, 99% of the virus was associated with the cellular debris. Finally, the presence of 5.0 mM ammonia in the culture medium was shown to seriously inhibit the reovirus yield, whereas lactate concentrations up to 20 mM had no effect. © 2004 Wiley Periodicals, Inc.
Whole cell–enzyme hybrid amperometric biosensor for direct determination of organophosphorous nerve agents with p‐nitrophenyl substituent
Authors: Lei Yu , Mulchandani Priti , Chen Wilfred , Wang Joseph , Mulchandani Ashok 
Published: February 2004

AbstractIn this paper, we reported the construction of a hybrid biosensor for direct, highly selective, sensitive, and rapid quantitative determination of organophosphate pesticides with p‐nitrophenyl substituent using purified organophosphorus hydrolase (OPH) for the initial hydrolysis and Arthrobacter sp. JS443 for subsequent p‐nitrophenol oxidation. The biocatalytic layer was prepared by co‐immobilizing Arthrobacter sp. JS443 and OPH on a carbon paste electrode. OPH catalyzed the hydrolysis of organophosphorus pesticides with p‐nitrophenyl substituent such as paraoxon and methyl parathion to release p‐nitrophenol that was oxidized by the enzymatic machinery of Arthrobacter sp. JS443 to carbon dioxide through electroactive intermediates 4‐nitrocatechol and 1,2,4‐benzenetriol. The oxidization current of the intermediates was measured and correlated to the concentration of organophosphates. The best sensitivity and response time were obtained using a sensor constructed with 0.06 mg dry weight of cell and 965 IU of OPH operating at 400 mV applied potential (vs. Ag/AgCl reference) in 50 mM citrate‐phosphate pH 7.5 buffer at room temperature. Using these conditions, the biosensor measured as low as 2.8 ppb (10 nM) of paraoxon and 5.3 ppb (20 nM) of methyl parathion without interference from phenolic compounds, carbamate pesticides, triazine herbicides, and organophosphate pesticides that do not have the p‐nitrophenyl substituent. The biosensor had excellent operational life‐time stability with no decrease in response for more than 40 repeated uses over a 12‐h period when stored at room temperature, while its storage life was approximately 2 days when stored in the operating buffer at 4°C. © 2004 Wiley Periodicals, Inc.
Biocatalytic transformation of petroporphyrins by chemical modified cytochrome C
Authors: García‐Arellano Humberto , Buenrostro‐Gonzalez Eduardo , Vazquez‐Duhalt Rafael 
Published: February 2004

AbstractA semi‐synthetic biocatalyst was prepared by a double chemical modification of cytochrome c. Free amino groups were modified with poly(ethylene glycol) while free carboxylic groups were alkylated to form methyl esters. The double chemically modified protein, PEG‐Cyt‐Met, oxidized synthetic porphyrins in a ternary solvent mixture composed by methylene chloride, methanol, and phosphate buffer. The highest activity was found in the ternary systems with low water content (5%). The use of relatively hydrophobic peroxides, such as tert‐butyl and cumene hydroperoxides, extended the operational life of the biocatalyst, which, in turn, resulted in an extended oxidation of the substrates tested. PEG‐Cyt‐Met is able to transform asphaltenes, a highly recalcitrant petroleum fraction. The huge energetic resource found as asphaltene‐rich deposits is the driving force to investigate and to innovate upgrading technologies, including biotechnological strategies. © 2004 Wiley Periodicals, Inc.
Uncoupling of cell growth and proliferation results in enhancement of productivity in p21CIP1‐arrested CHO cells
Authors: Bi Jing‐Xiu , Shuttleworth John , Al‐Rubeai Mohamed 
Published: February 2004

AbstractChinese hamster ovary cells have been engineered to inducibly over‐express the p21CIP1 cyclin‐dependent kinase inhibitor, to achieve cell cycle arrest and increase cell productivity. In p21CIP1‐arrested cells production of antibody from a stably integrated lgG4 gene, was enhanced approximately fourfold. The underlying physiological basis for enhanced productivity was investigated by measuring a range of cellular and metabolic parameters. Interestingly, the average cell volume of arrested cells was approximately fourfold greater than that of proliferating cells. This was accompanied by significant increases in mitochondrial mass, mitochondrial activity, and ribosomal protein S6 levels. Our results suggest that p21CIP1‐induced cell cycle arrest uncouples cell growth from cell‐cycle progression, and provides new insight into how improved productivity can be achieved in a cell line commonly used for large‐scale production of pharmaceutical proteins. © 2004 Wiley Periodicals, Inc.
Expression of a single‐chain human interleukin‐12 gene in transgenic tobacco plants and functional studies
Authors: Gutiérrez‐Ortega Abel , Ávila‐Moreno Federico , Saucedo‐Arias Luis Jorge , Sánchez‐Torres Carmen , Gómez‐Lim Miguel Ángel 
Published: February 2004

AbstractInterleukin 12 (IL‐12) is a key heterodimeric cytokine produced by a variety of antigen‐presenting cells, including dendritic cells, macrophages, and B cells. It displays a potent array of biological activities affecting natural killer (NK) and T cells. These activities include promotion of cell‐mediated or type 1 T helper cell responses (Th1). Due to that property, IL‐12 has been employed in cancer immunotherapy, in mouse models of infectious diseases and in airway inflammation, and it may also have utility as a vaccine adjuvant. Transgenic plants are being used in many laboratories around the world for the production of therapeutically valuable proteins and as vehicles for oral vaccines. Here we present the expression of a single‐chain human interleukin‐12 in transgenic tobacco plants. The biological activity of plant‐produced IL‐12 was determined by interferon gamma (IFN‐γ) production by natural killer (NK) cells, and the level of production was comparable to that obtained with commercially available recombinant IL‐12. The potential use of this recombinant protein is discussed. © 2004 Wiley Periodicals, Inc.
Redundant men: constraints on identity change
Authors: Willott Sara , Griffin Christine 
Published: February 2004

AbstractIn this article the constraints on identity change for a group of working class men experiencing long‐term unemployment in the UK is examined. Despite their lack of access to paid employment, these men continued to construct their gender identity around the breadwinner persona. The theoretical framework employed concepts from both Connell and Bourdieu. Based on discourse analysed data collected from a series of four loosely structured group discussions, it is argued here that these men had (i) less access to capital generally and (ii) reduced access to ‘useful’ types of capital resources. In other words, these groups of men have fewer resources to hand in constructing masculine identities that reflect the changing structural and ideological demands of the current social‐historical period. Copyright © 2004 John Wiley & Sons, Ltd.
You still feel different: the experience and meaning of women's self‐injury in the context of a lesbian or bisexual identity
Authors: Alexander Natasha , Clare Linda 
Published: February 2004

AbstractThis article reports an intensive qualitative study of the subjective experience and meaning of self‐injury for 16 women who identified as lesbian or bisexual and who had deliberately self‐injured on repeated occasions. In individual interviews, the women talked about their experiences of self‐injury and the role it played in their lives as lesbian or bisexual women. Interpretative Phenomenological Analysis (IPA) was used to elicit themes arising within their accounts. These highlighted a number of ways in which social and contextual factors contributed to the development of self‐injury. Although many of these factors seemed applicable to any woman who self‐injures, there were some aspects that were specific to the experience of lesbian and bisexual women. In addition, the women's accounts raised a number of important issues about the way in which mental health services respond to lesbian and bisexual women who self‐injure. It is argued that self‐injury can be understood as a coping response that arises within a social context characterized by abuse, invalidation, and the experience of being regarded as different or in some way unacceptable. These factors are especially salient in the lives of women, and they emerge particularly strongly as part of the experience of women who are developing a lesbian or bisexual identity. Copyright © 2004 John Wiley & Sons, Ltd.
Radical psychology networks: a review and guide
Authors: Burton Mark 
Published: February 2004

AbstractMovements of psychologists with a liberatory agenda have emerged in a number of countries. A guide and overview is offered here. These networks have not yet developed into a particularly strong movement. Some of the reasons for this will be discussed in relation to the contradictory role of mainstream psychology as both loyal critic and as resource for the ruling order. Copyright © 2004 John Wiley & Sons, Ltd.
Different Roles of Electrostatics in Heat and in Cold: Adaptation by Citrate Synthase
Authors: Kumar Sandeep , Nussinov Ruth 
Published: February 2004

AbstractElectrostatics plays a major role in heat adaptation by thermophilic proteins. Here we ask whether electrostatics similarly contributes to cold adaptation in psychrophilic proteins. We compare the sequences and structures of citrate synthases from the psychrophile Arthobacter Ds2–3R, from chicken, and from the hyperthermophile Pyrococcus furiosus. The three enzymes share similar packing, burial of nonpolar surface area, and main‐chain hydrogen bonding. However, both psychrophilic and hyperthermophilic citrate synthases contain more charged residues, salt bridges, and salt‐bridge networks than the mesophile. The electrostatic free‐energy contributions toward protein stability by individual charged residues show greater variabilities in the psychrophilic citrate synthase than in the hyperthermophilic enzyme. The charged residues in the active‐site regions of the psychrophile are more destabilizing than those in the active‐site regions of the hyperthermophile. In the hyperthermophilic enzyme, salt bridges and their networks largely cluster in the active‐site regions and at the dimer interface. In contrast, in the psychrophile, they are more dispersed throughout the structure. On average, salt bridges and their networks provide greater electrostatic stabilization to the thermophilic citrate synthase at 100 °C than to the psychrophilic enzyme at 0 °C. Electrostatics appears to play an important role in both heat and cold adaptation of citrate synthase. However, remarkably, the role may be different in the two types of enzyme: In the hyperthermophile, it may contribute to the integrity of both the protein dimer and the active site by possibly countering conformational disorder at high temperatures. On the other hand, in the psychrophile at low temperatures, electrostatics may contribute to enhance protein solvation and to ensure active‐site flexibility.
Structural Models of the Photointermediates in the Rhodopsin Photocascade, Lumirhodopsin, Metarhodopsin I, and Metarhodopsin II
Authors: Ishiguro Masaji , Oyama Yoshiaki , Hirano Takahiro 
Published: February 2004

AbstractModel building of the two photointermediates, lumirhodopsin and metarhodopsin I, and the activated form of rhodopsin, metarhodopsin II, is described. An outward swing of the C‐terminal portion of transmembrane segment 3, pivoting on Cys110 at the N‐terminal end of transmembrane segment 3, led to structural models of lumirhodopsin and metarhodopsin I. The conformation of the chromophore in the lumirhodopsin and metarhodopsin I models is controlled by the motion of transmembrane segment 3 and agreed closely with the hydrogen‐bonding states of the protonated Schiff base in lumirhodopsin and metarhodopsin I as deduced from their FTIR and resonance Raman spectra and with the negative and positive CD bands of lumirhodopsin and metarhodopsin I, respectively. The structure of metarhodopsin II was constructed by an outward swing of transmembrane segment 3 and the rigid‐body motion of transmembrane segment 6. The arrangement of the entire transmembrane segment of the metarhodopsin II model closely agreed with the electron paramagnetic resonance spectra of spin‐labeled rhodopsin mutants and provided a structural basis for the protonation of Glu134, which is a key process in transducin activation.
Surface‐Functionalized Nanoparticle Library Yields Probes for Apoptotic Cells
Authors: Schellenberger Eyk A. , Reynolds Fred , Weissleder Ralph , Josephson Lee 
Published: February 2004

AbstractWe have developed techniques for the efficient synthesis and screening of small libraries of surface‐functionalized nanoparticles for the recognition of specific types of cells. To illustrate this concept we describe the development of a nanoparticle that preferentially recognizes apoptotic Jurkat cells in a manner similar to the apoptosis‐recognizing protein annexin V. The nanoparticle, which is detectable by fluorescence or NMR relaxometry, was analyzed for the ability to recognize normal and apoptotic cells by fluorescence‐activated cell sorting (FACS) analysis and fluorescence microscopy. The capability to develop nanoparticles which interact with specific target cells could be applied to the design of materials for diverse applications including quantum dots, which serve as fluorescence tracers, colloidal gold, which serves as a tracer for electron micrographs, or the crystalline forms of drugs.
Use of Magnetic Nanoparticles as Nanosensors to Probe for Molecular Interactions
Authors: Perez J. Manuel , Josephson Lee , Weissleder Ralph 
Published: February 2004

AbstractBiocompatible magnetic nanosensors have been designed to detect molecular interactions in biological media. Upon target binding, these nanosensors cause changes in the spin–spin relaxation times of neighboring water molecules, which can be detected by magnetic resonance (NMR/MRI) techniques. These magnetic nanosensors have been designed to detect specific mRNA, proteins, enzymatic activity, and pathogens (e.g., virus) with sensitivity in the low femtomole range (0.5–30 fmol).
Adeno‐Associated Virus Rep78/Rep68 Promotes Localized Melting of the Rep Binding Element in the Absence of Adenosine Triphosphate
Authors: Lou Hua Jane , Brister J. Rodney , Li Jianwei Jeffery , Chen Weijun , Muzyczka Nicholas , Tan Weihong 
Published: February 2004

AbstractWe have applied fluorescence anisotropy and molecular beacon fluorescence methods to study the interactions between the Adeno‐associated virus Rep78/Rep68 protein and the 23‐bp Rep binding element (RBE). Rep78/Rep68 stably interacted with both the single‐ and double‐stranded conformations of the RBE, but the interaction mechanisms of single‐ and double‐stranded DNA appeared to be fundamentally different. The stoichiometry of Rep78 association with both the separate top and bottom strands of the RBE was 1:1, and the relative dissociation constant (KD) values of these associations were calculated to be 2.3×10−8 and 3.2×10−8 M, respectively. In contrast, the stoichiometry of Rep78 association with the double‐stranded RBE was 2:1, and the dissociation constant was determined to be 4.2×10−15 M2. Moreover, Rep78/Rep68 interaction with the 23‐bp duplex RBE appeared to cause localized melting of the double‐stranded DNA substrate in the absence of adenosine triphosphate (ATP). This melting activity showed slower kinetics than binding and may contribute to the initiation of ATP‐dependent Rep78 helicase activity.
Optimal Modification of Annexin V with Fluorescent Dyes
Authors: Schellenberger Eyk A. , Weissleder Ralph , Josephson Lee 
Published: February 2004

AbstractThe many uses of chemically modified annexin Vs necessitate an understanding of the optimal degree of modification and modification sites of the protein. When reacted with the N‐hydroxysuccinimide ester of Cy5.5, annexin V with one modification per mole of protein retained its affinity for phosphatidylserine of apoptotic cells, whereas modification with two dyes per mole of protein caused a complete loss of activity. A tryptic digest LC/MS method was used to identify the modification sites as either of two closely spaced lysine residues, in position 286 or 290. The crystal structure indicated the location of these lysines was distal to the phosphatidylserine binding sites on annexin V. These results can be used to develop active or inactive fluorescent control annexin V proteins and to suggest strategies for attaining higher levels of modification with retention of bioactivity.
Increased Single‐Nucleotide Discrimination of PCR by Primer Probes Bearing Hydrophobic 4′C Modifications
Authors: Strerath Michael , Gaster Jens , Summerer Daniel , Marx Andreas 
Published: February 2004

AbstractWe report on significantly increased selectivity of real‐time PCR through employment of primer probes that bear hydrophobic 4′C modifications at the 3′‐terminal nucleotide. The primer probes were designed to bind the target sequences in such a way that the 3′‐terminal nucleotide defines whether a matched or a single mismatched basepair is present depending on the respective target sequence. Several commercially available thermostable DNA polymerases belonging to different DNA polymerase families were tested for their efficacy in discriminating between PCR amplification of matched substrates and duplexes that contain a single mismatch. It turned out that, depending on the 4′C modification and the employed DNA polymerase, significantly increased differentiation between single matches and mismatches could be observed with real‐time PCR. The degrees of the observed effects varied with the employed 4′C modification and the sequence context studied. The system is robust enough to work faithfully under several buffer conditions. Our approach should be useful for the direct diagnosis of single nucleotide variations within genes, like single nucleotide polymorphisms or mutations, by PCR without the need for further time‐ and cost‐intensive post‐PCR analysis.
Copper Binding to the Neurotoxic Peptide PrP106–126: Thermodynamic and Structural Studies
Authors: Belosi Barbara , Gaggelli Elena , Guerrini Remo , Kozłowski Henryk , Łuczkowski Marek , Mancini Francesca M. , Remelli Maurizio , Valensin Daniela , Valensin Gianni 
Published: February 2004

AbstractThe human prion protein fragment PrP106–126 is a highly fibrillogenic peptide, resistant to proteinases and toxic to neurons; it derives from the normal prion protein (PrPC), with which it can interact, thus inhibiting its superoxide dismutase‐like activity. The same properties are also shown by the abnormal isoform of the prion protein (PrPSc), and this similarity makes PrP106–126 an interesting model for the neurotoxic action of PrPSc. A role for copper in PrP106–126 aggregation and toxicity has recently been evidenced, and the interaction of terminal Lys, His and Met residues with the copper ion at neutral pH has been suggested. In order to shed more light on the complex‐formation equilibria of PrP106–126 with the copper ion, a thorough investigation has been carried out by means of several experimental techniques: potentiometry, solution calorimetry, VIS spectrophotometry, circular dichroism, EPR and NMR spectroscopy. A shorter and more soluble fragment—PrP106–113, which lacks the hydrophobic C‐terminal domain of PrP106–126 but contains all the potential donor groups—has also been considered for the sake of comparison. The involvement of terminal amino, imidazolic and amido nitrogens in complex formation has been confirmed, while no evidence was found for the interaction of side chains of Met and Lys residues with the copper ion. Solution structures for the main complexes are suggested.
LES Simulation of Jet Mixing Processes With Heat Transfer in Turbulent Pipe Flow
Authors: Jahnke S. , Kornev N. , Leder A. , Hassel E. 
Published: February 2004

AbstractA LES technique is used for investigation of jet mixing processes with heat transfer in a turbulent pipe flow. Predictions were validated for different test problems. Influence of velocity, density, kinematic viscosity and temperature in a co‐flow and in an admixture as well as the effect of the Reynolds number on mixing were studied. Two efficient methods of mixing control, namely periodic injection and swirling jets, were investigated.