bluuebunny/crossref_metadata_2025_split huggingface dataset:
Application of Pseudomonas putida PpG 786 Containing P‐450 Cytochrome Monooxygenase for Removal of Trace Naphthalene Concentrations
Authors: Kulisch Gail P. , Vilker Vincent L. 
Published: March 2005

AbstractThis study explores the potential for a bacterial monooxygenase to remove polynuclear aromatic hydrocarbons from aqueous solutions at high rates. This is part of a larger effort to test the versatility of the cytochrome P‐450cam monooxygenase enzyme system for detoxification of industrial process wastewaters that contain trace quantities of hazardous compounds like PAHs or halocarbons. The intracellular concentration of P‐450cam in washed, resting cell suspensions of Pseudomonoas putida PpG 786 that were cultured on camphor was measured by adapting a spectrophotometric method used to measure P‐450 concentration in extracts of mammalian tissues. Naphthalene removal in the suspensions was measured as a function of incubation time, biomass concentration, starting naphthalene concentration (3‐180 μmol/L) and in the presence of known P‐450 inhibitors. Involvement of the P‐450cam system in the measured naphthalene disappearance was established by showing that while significant naphthalene removal occurred in camphor‐grown biomass, no disappearance was observed in glutamate‐grown biomass and that removal was turned off in the presence of the P‐450 inhibitor metyrapone. The half‐life of naphthalene removal for a 1 ppm solution (7.8 μM) was about 18 h. The fraction of naphthalene removed descreased rapidly as initial naphthalene concentration increased, and essentially no naphthalene was removed when the starting concentration exceeded 189 μmol/L (23 ppm).
Antibody Immobilization onto Glow Discharge Treated Polymers
Authors: Safranj Agneza , Kiaei David , Hoffman Allan S. 
Published: March 2005

AbstractPrevious studies have shown that certain glow discharge treated polymers strongly retain adsorbed albumin and fibrinogen. On the basis of this phenomenon, we have investigated the possibility of immobilizing antibodies on glow discharge treated surfaces for diagnostic immunoassay applications. As a model for antibody immobilization, bovine IgG was immobilized on the following polymers: polyethylene (PE), tetraflu‐oroethylene glow discharge treated PE (TFE/PE), poly(ethylene terephthalate) (PET), TFE/PET, poly(tetrafluoroethylene) (PTFE), ethylene glow discharge treated PET (E/PET) and hexamethyldisiloxane glow discharge treated PET (HMDS/PET). IgG was radiolabeled with 125I and immobilized by either of the following two methods: (a) physical adsorption of IgG on untreated and glow discharge treated polymers or (b) physical adsorption of albumin followed by chemical coupling of IgG to albumin by glutaraldehyde. IgG concentration as well as adsorption times were varied in order both to optimize the immobilization conditions and to investigate the adsorption and retention mechanisms. To evaluate the efficiency of the immobilization techniques, blood plasma, Tween‐20, and sodium dodecyl sulfate (SDS) were used to elute the adsorbed IgG layer. We found that IgG was successfully immobilized on the fluorocarbon glow discharge treated surfaces by using either the physical adsorption or the glutaraldehyde coupling method, although the former is more efficient than the latter method. Only 15% of the IgG adsorbed on TFE/PE for 4 h was eluted by SDS. In contrast, 75% of the IgG was eluted from untreated PE by SDS. Both Tween‐20 and blood plasma were less effective than SDS in eluting the adsorbed IgG. Preliminary results indicate that antibodies immobilized by the first method retain their antigen binding capability.
High‐Resolution Particle Size Analysis in Biotechnology Process Control
Authors: Thomas John C. , Middelberg Anton P. J. , Hamel Jean‐Francois , Snoswell Mark A. 
Published: March 2005

AbstractMany industrially important proteins can now be expressed intracellularly as insoluble protein inclusion bodies. In production, large‐scale centrifugation is commonly used to separate and recover the inclusion bodies. Recovery efficiency depends critically on the centrifuge feed rate, which must be optimized to minimize production costs. We have used a disc centrifuge photosedimentometer to make high‐resolution measurements of the particle size distribution (PSD) of the supernatant during the production of porcine somatotropin (pST) inclusion bodies. These measurements readily monitor the breakthrough of inclusion bodies into the supernatant and allow the centrifugation operation to be optimized.
Determination of the Effect of Moisture on Gliadin Glass Transition Using Mechanical Spectrometry and Differential Scanning Calorimetry
Authors: Graaf E. M. De , Madeka H. , Cocero A. M. , Kokini J. L. 
Published: March 2005

AbstractGliadin showed a glass to rubber transition typical of an amorphous polymer. Mechanical spectrometry and differential scanning calorimetry were used to determine the glass transition temperature (Tg) in the moisture range of 6.2–27.2% (wet basis, wb) and bone dry to 16.6% (wb), respectively. The Tg obtained with both of these techniques could be superimposed. The Tg could be successfully predicted using the Gordon‐Taylor equation.
Optimization of Baker's Yeast Alcohol Dehydrogenase Activity in an Organic Solvent
Authors: Yang Fangxiao , Russell Alan J. 
Published: March 2005

AbstractAlcohol dehydrogenase from baker's yeast (YADH) has been used to oxidize an unsaturated alcohol, 3‐methyl‐2‐buten‐l‐ol (UOL), to the corresponding unsaturated aldehyde, 3‐methyl‐2‐butenal (UAL), in heptane. The influence of total system water content, coenzyme NAD to enzyme molar ratio prior to catalyst preparation, and enzyme concentration on the conversion and redox reaction rates were investigated. The optimal water content was found to be 0.25‐0.5% (v/v), and a molar ratio of NAD to enzyme of 2.15 is recommended on the basis of economic and kinetic data. A maximal initial reaction rate for YADH of 0.02 mM/min/mg was observed under optimal conditions. The minimum cofactor turnover number was also determined under all conditions, and the effect of doping the catalyst with extra binding sites for NAD was investigated. The effect of substrate on enzyme stability has also been investigated. Interestingly, when the enzyme is preincubated in heptane, its initial activity can be increased 3‐fold.
Glycosidase Activities in Chinese Hamster Ovary Cell Lysate and Cell Culture Supernatant
Authors: Gramer Michael J. , Goochee Charles F. 
Published: March 2005

AbstractTo probe the potential for extracellular degradation of glycoprotein oligosaccharides in conjunction with Chinese hamster ovary (CHO) cell culture, an initial characterization of several CHO cell glycosidases was performed using 4‐methylumbelliferyl substrates. CHO cell lysates contained sialidase, β‐galactosidase, β‐hexosaminidase, and fucosidase activities with pH optimums near 5.5, 4, 6, and 6.5, respectively. These glycosidase activities were also present in cell‐free supernatant samples from commercial CHO cell cultures. The sialidase activity was further characterized. In contrast to previous reports concerning mammalian sialidases, the sialidase activity in CHO cell lysate retained considerable activity at pH 7 and was very stable, with a half‐life of 57 h at 37°C. Both the Km and Vmax of CHO lysate sialidase for 2′–(4‐methylumbelliferyl)‐a‐D‐N‐acetylneuraminic acid (4MU‐NeuAc) varied with pH, and this activity was competitively inhibited by 2, 3‐dehydro‐2‐deoxy‐N‐acetylneuraminic acid and by free N‐acetylneuraminic acid. The kinetic characteristics and pH‐activity profiles of the CHO cell lysate and cell culture supernatant sialidase activities were essentially identical, and both released sialic acid from the glycoprotein fetuin at pH 7.5. These results suggest that the oligosaccharides of glycoproteins secreted by CHO cells can potentially be modified extracellularly by sialidase under culture conditions which promote the release and extracellular accumulation of this enzyme.
Reversed Micellar Extraction of Charged Fusion Proteins
Authors: Forney Craig E. , Glatz Charles E. 
Published: March 2005

AbstractWe have investigated the use of charged fusion tails with the enzyme glucoamylase in reversed micellar extraction. The addition of the charged tails increased the fraction of enzymatically active protein recovered at a given pH, with the tails containing the largest number of charges being recovered at the highest level. The series of mutations also allows for investigation of the charge‐dependent behavior of reversed micellar extraction. However, in this case, the change in protein charge via fusions had a lesser impact than did the change in charge via a pH change. The difference may be due to the difficulty of partitioning the hydrodynamically larger fusion protein.
Transcutaneous Fluorescence Dilution Cardiac Output and Circulating Blood Volume during Hemorrhagic Hypovolemia
Authors: Maarek Jean-Michel I. , Holschneider Daniel P. , Yang Jun , Pniak Sarah N. , Rubinstein Eduardo H. 
Published: March 2005

Background
Cardiac output and circulating blood volume are important parameters for assessing cardiac function in the intensive care setting and during major surgeries. The authors tested in an animal model of hemorrhagic hypovolemia the feasibility of measuring these parameters simultaneously by transcutaneous fluorescence monitoring of an intravenous bolus injection of indocyanine green.

Methods
Fluorescence dilution cardiac output was measured in seven anesthetized rabbits and compared to thermodilution cardiac output. The optical probe used to excite the indocyanine green fluorescence was in contact with the skin above the ear artery. Local heating enhanced blood perfusion of the measurement site. Cardiac output was measured during baseline conditions, during hemorrhagic hypovolemia, and after partial restoration of the blood volume with reinfused blood. Estimates of the circulating blood volume were simultaneously obtained from the analysis of the fluorescence dilution traces.

Results
Cardiac output measured by fluorescence dilution (thermodilution) averaged 455 +/- 16 (450 +/- 13) ml/min in baseline conditions and 323 +/- 15 (330 +/- 13) ml/min during hypovolemia. Fluorescence dilution cardiac output was linearly related to thermodilution cardiac output (slope = 1.13 +/- 0.05, ordinate = -50 +/- 19 ml/min, R = 0.92). Interanimal differences explained most of the variance between cardiac output estimates obtained with the two techniques. Circulating blood volume decreased from 204 +/- 5 ml in baseline conditions to 174 +/- 8 ml after bleeding and reflected blood volume changes in this acute bleeding-reinfusion model.

Conclusions
The study extends the applicability of the fluorescence dilution technique for cardiac output measurement to hypovolemic conditions and demonstrates its ability to produce accurate estimates of the circulating blood volume in experimental animals.
Differential Effects of Bupivacaine and Ropivacaine Enantiomers on Intracellular Ca2+Regulation in Murine Skeletal Muscle Fibers
Authors: Zink Wolfgang , Missler Goetz , Sinner Barbara , Martin Eike , Fink Rainer H. A. , Graf Bernhard M. 
Published: March 2005

Background
Increased intracellular Ca concentrations are considered to be a major pathomechanism in local anesthetic myotoxicity. Racemic bupivacaine and S-ropivacaine cause Ca release from the sarcoplasmic reticulum of skeletal muscle fibers and simultaneously inhibit Ca reuptake. Examining the optical isomers of both agents, the authors investigated stereoselective effects on muscular Ca regulation to get a closer insight in subcellular mechanisms of local anesthetic myotoxicity.

Methods
R- and S-enantiomers as well as racemic mixtures of both agents were tested in concentrations of 1, 5, 10, and 15 mm. Saponin-skinned muscle fibers from the extensor digitorum longus muscle of BALB/c mice were examined according to a standardized procedure. For the assessment of effects on Ca uptake and release from the sarcoplasmic reticulum, agents were added to the loading solution and the release solution, respectively, and force and Ca transients were monitored.

Results
The effects of S-enantiomers on both Ca release and reuptake were significantly more pronounced than those of racemic mixtures and R-enantiomers, respectively. In addition, the effects of racemates were markedly stronger than those of R-enantiomers. With regard to Ca release, the effects of bupivacaine isomers were more pronounced than the isomers of ropivacaine.

Conclusions
These data show that stereoselectivity is involved in alterations of intracellular Ca regulation by bupivacaine and ropivacaine. S-enantiomers seem to be more potent than R-enantiomers, with intermediate effects of racemic mixtures. In addition, lipophilicity also seems to determine the extent of Ca release by local anesthetics.
Monitoring global rates of biodiversity change: challenges that arise in meeting the Convention on Biological Diversity (CBD) 2010 goals
Authors: Dobson Andy 
Published: March 2005

By agreeing to strive for ‘a significant reduction in the current rate of loss of biological diversity’ by the year 2010, political leaders at the 2002 World Summit on Sustainable Development (held in Johannesburg, South Africa) presented conservation scientists with a great opportunity, but also one of their most significant challenges. This is an extremely exciting and laudable development, but this reporting process could be made yet more powerful if it incorporates, from the outset, independent scientific assessment of the measures, how they are analysed, and practical ways of plugging key gaps. This input is crucial if the measures are to be widely owned, credible and robust to the vigorous external scrutiny to which they will doubtless be exposed. Assessing how rates of biodiversity loss have changed from current levels by 2010 will require that a given attribute has been measured at least three times; however, most habitats, species, populations and ecosystem services have not been assessed even once. Furthermore, the best data on which to base estimates of biodiversity loss are biased towards the charismatic vertebrate species; unfortunately, these supply minimal services to the human economy. We have to find ways to redress this taxonomic imbalance and expand our analyses to consider the vast diversity of invertebrate, fungal and microbial species that play a role in determining human health and economic welfare.In the first part of this paper I will use examples from local and regional monitoring of biological diversity to examine the desired properties of ‘ideal indicators’. I will then change focus and examine an initial framework that asks how we might monitor changes in the economic goods and services provided by natural ecosystems. I will use this exercise to examine how the set of possible indicators given by the Convention on Biological Diversity might be modified in ways that provide a more critical assay of the economic value of biological diversity. Here I will emphasize that we need not only to monitor these benefits, but also to significantly increase public awareness of human dependence upon the role that non-voting species play in driving the world's financial economy.
Individual-Based Modelling Potentials and Limitations
Authors: Breckling Broder 
Published: March 2005

Individual-based modelling (IBM) is an important option in ecology for the study of specific properties of complex ecological interaction networks. The main application of this model type is the analysis of population characteristics at high resolution. IBM also contributes to the advancement of ecological theory. One of the remarkable potentials of the approach is the possibility of studying self-organization and emergent properties that arise from individual actions on higher integration levels, especially on the population level.This review outlines the background and different application fields of individual-based models together with a short description of the technical implications of model setup. The limitations of this modelling approach result from the technical basis of model construction, which can handle a limited number of active entities only. Limits in biological knowledge also restrict the application of this model type. The paper presents some individual-based models that have been developed for different purposes and briefly discusses these models. Concerning the perspective of IBM, a coincidence with developments in artificial life research is explained. IBM shifts the focus of ecological analysis of dynamic systems from structurally fixed settings to the analysis of self-organizing interaction patterns that are variable in quantity and quality.
Probing the pH‐dependent structural features of α‐KTx12.1, a potassium channel blocker from the scorpion Tityus serrulatus
Authors: Oyama Sérgio , Pristovšek Primož , Franzoni Lorella , Pertinhez Thelma A. , Schininá Eugenia , Lücke Christian , Rüterjans Heinz , Arantes Eliane Candiani , Spisni Alberto 
Published: March 2005

AbstractPotassium channels are widespread in living cells and are involved in many diseases. The scorpion toxin α‐KTx12.1 interacts with various K+ channels, suggesting its capacity to match diverse channel pores. It is recognized that tissue injuries may affect the pH at toxins site of action, thereby modulating both protein conformation and activity. To better understand its molecular mechanism of action, we studied α‐KTx12.1 using pH as a tool to explore its plasticity and NMR in combination with MD calculations to detect it. The toxin solution structure consists of an α‐helix and a triple‐stranded β‐sheet stabilized by four disulfide bridges. The NMR results show, in addition, that His28 possesses an unusually low pKa of 5.2. The best set of protein conformers is obtained at pH 4.5, while at pH 7.0, the reduced number of NOEs resulting from a faster hydrogen exchange does not allow to reach a good structural convergence. Nonetheless, MD calculations show that the toxin structure does not vary significantly in that pH range, while conformational changes and modifications of the surface charge distribution occur when His28 is fully protonated. Moreover, essential dynamics analysis reveals variations in the toxin's coherent motions. In conclusion, His28, with its low pKa value, provides α‐KTx12.1 with the ability to preserve its active conformation over a wide pH interval, thus expanding the range of cellular conditions where the toxin can fully exhibit its activity. Overall, the results further underline the role of histidine as a natural controller of proteins' functionality.
Influence of denatured and intermediate states of folding on protein aggregation
Authors: Fawzi Nicolas L. , Chubukov Victor , Clark Louis A. , Brown Scott , Head‐Gordon Teresa 
Published: March 2005

AbstractWe simulate the aggregation thermodynamics and kinetics of proteins L and G, each of which self‐assembles to the same β/β topology through distinct folding mechanisms. We find that the aggregation kinetics of both proteins at an experimentally relevant concentration exhibit both fast and slow aggregation pathways, although a greater proportion of protein G aggregation events are slow relative to those of found for protein L. These kinetic differences are correlated with the amount and distribution of intrachain contacts formed in the denatured state ensemble (DSE), or an intermediate state ensemble (ISE) if it exists, as well as the folding timescales of the two proteins. Protein G aggregates more slowly than protein L due to its rapidly formed folding intermediate, which exhibits native intrachain contacts spread across the protein, suggesting that certain early folding intermediates may be selected for by evolution due to their protective role against unwanted aggregation. Protein L shows only localized native structure in the DSE with timescales of folding that are commensurate with the aggregation timescale, leaving it vulnerable to domain swapping or nonnative interactions with other chains that increase the aggregation rate. Folding experiments that characterize the structural signatures of the DSE, ISE, or the transition state ensemble (TSE) under nonaggregating conditions should be able to predict regions where interchain contacts will be made in the aggregate, and to predict slower aggregation rates for proteins with contacts that are dispersed across the fold. Since proteins L and G can both form amyloid fibrils, this work also provides mechanistic and structural insight into the formation of prefibrillar species.
Evolution of distinct EGF domains with specific functions
Authors: Wouters Merridee A. , Rigoutsos Isidore , Chu Carmen K. , Feng Lina L. , Sparrow Duncan B. , Dunwoodie Sally L. 
Published: March 2005

AbstractEGF domains are extracellular protein modules cross‐linked by three intradomain disulfides. Past studies suggest the existence of two types of EGF domain with three‐disulfides, human EGF‐like (hEGF) domains and complement C1r‐like (cEGF) domains, but to date no functional information has been related to the two different types, and they are not differentiated in sequence or structure databases. We have developed new sequence patterns based on the different C‐termini to search specifically for the two types of EGF domains in sequence databases. The exhibited sensitivity and specificity of the new pattern‐based method represents a significant advancement over the currently available sequence detection techniques. We re‐annotated EGF sequences in the latest release of Swiss‐Prot looking for functional relationships that might correlate with EGF type. We show that important post‐translational modifications of three‐disulfide EGFs, including unusual forms of glycosylation and post‐translational proteolytic processing, are dependent on EGF subtype. For example, EGF domains that are shed from the cell surface and mediate intercellular signaling are all hEGFs, as are all human EGF receptor family ligands. Additional experimental data suggest that functional specialization has accompanied subtype divergence. Based on our structural analysis of EGF domains with three‐disulfide bonds and comparison to laminin and integrin‐like EGF domains with an additional inter‐domain disulfide, we propose that these hEGF and cEGF domains may have arisen from a four‐disulfide ancestor by selective loss of different cysteine residues.
Multiple sclerosis
Authors: Hafler David A. , Slavik Jacqueline M. , Anderson David E. , O'Connor Kevin C. , De Jager Philip , Baecher‐Allan Clare 
Published: March 2005

Summary:  Multiple sclerosis (MS) is a complex genetic disease associated with inflammation in the central nervous system (CNS) white matter and is thought to be mediated by autoimmune processes. Clonal expansion of B cells, their antibody products, and T cells, hallmarks of inflammation in the CNS, are found in MS. The association of the disease with major histocompatibility complex genes, the inflammatory white matter infiltrates, similarities with animal models, and the observation that MS can be treated with immunomodulatory and immunosuppressive therapies support the hypothesis that autoimmunity plays a major role in the disease pathology.This review discusses the immunopathology of MS with particular focus given to regulatory T cells and the role of B cells and antibodies, immunomodulatory therapeutics, and finally new directions in MS research, particularly new methods to define the molecular pathology of human disease with high‐throughput examination of germline DNA haplotypes, RNA expression, and protein structures that will allow the generation of a new series of hypotheses that can be tested to develop better understandings and therapies for this disease.