bluuebunny/crossref_metadata_2025_split huggingface dataset:
U2 and U1 snRNA gene loci associate with coiled bodies
Authors: Smith Kelly P. , Carter Kenneth C. , Johnson Carol V. , Lawrence Jeanne Bentley 
Published: May 2005

AbstractThe coiled bodies are nuclear structures rich in a variety of nuclear and nucleolar components including snRNAs. We have investigated the possibility that coiled bodies may associate with snRNA genes and report here that there is a high degree of association between U2 and U1 genes with a subset of coiled bodies. As investigated in human HeLa cells grown in monolayer culture, about 75% of the nuclei had at least one U2 gene associated with a coiled body, and 45% had at least one U1 locus associated. In another suspension‐grown HeLa cell strain, 92% of cells showed association of one or more U2 genes with coiled bodies. In contrast to the U2 and U1 gene associations, a locus closely linked to the U2 gene cluster appeared associated with a coiled body only in 10% of cells. Associated snRNA gene signals were repeatedly positioned at the edge of the coiled body. Thus, this association was highly nonrandom and spatically precise. Our analysis revealed a much higher frequency of association for closely spaced “doublet” U2 gene signals, with over 80% of paired signals associated as opposed to 35% for single U2 signals. This finding, coupled with the fact that not all genes were associated in all cells, suggested the possibility of a cell‐cycle‐dependent, possibly S‐phase, association. However, an analysis of S‐ and non‐S‐phase cells using BrdU incorporation or cell synchronization did not indicate an increased level of association in S‐phase. These and other results suggested that a substantial fraction of paired U2 signals represented association of U2 genes on homologous chromosomes rather than only replicated DNA. Furthermore, triple lable analysis showed that in a significant fraction of cells U1 and U2 genes were both associated with the same coiled body. U1 and U2 genes were closely paired in approximately 20% of cells, over 60% of which were associated with a readily identifiable coiled body. This finding raises the possibility that multiple genes of a particular class may be in association with each coiled body. Thus, the coiled body may be a dynamic structure which transiently interacts with or is formed by one or more specific genetic loci, possibly carrying out some function related to their expression. © 1995 Wiley‐Liss, Inc.
Nuclear domain 10 (ND10) associated proteins are also present in nuclear bodies and redistribute to hundreds of nuclear sites after stress
Authors: Maul Gerd G. , Yu Eunsil , Ishov Alexander M. , Epstein Alan L. 
Published: May 2005

AbstractThe promyelocytic leukemia protien fused to the retinoic acid receptor in t(15;17) acute promyelocytic leukemia, the primary biliary cirrhosis autoantigen, Sp100, as well as the incompletely charterized protien NDP55, are co‐localized in specific immunohistochemically defined nuclear domains (ND10), which are potential equyivalents of ultrastructurally defined nuclear bodies. We investigated whether the distribution of these proteins depends on environmental conditions and whether ND10 correlate with nuclear bodies. Certain nuclear bodies and ND10 react in a similar bodies, which herpes simplex virus infection or heat shock modify both. Redistribution of ND10‐associated proteins to hundreds of small sites throughout the chromatin was inducible by stress in the form of heat shock and exposure to Cd++ ions. The change of distribution was rapid and independent of proteins synthesis, and thus not part of the classical heat shock response. The very rapid redistribution of these proteins after heat shock, together with the development of ND10 upon interferon actication, raises the possibility that ND10 represent storage sites of certain matrix proteins readily accessible throughout the chromatin in response to stress or other effectors that induce global nuclear changes. © 1995 Wiley‐Liss, Inc.
Prothrombin cleavage by human vascular smooth muscle cells: A potential alternative pathway to the coagulation cascade
Authors: Benzakour Omar , Kanthou Chryso , Lupu Florea , Dennehy Ulla , Goodwin Chris , Scully Michael F. , Kakkar Vijay V. , Cooper David N. 
Published: May 2005

AbstractThrombin is a potent mitogen for human vascular smooth muscle cells (HVSMC) and its enzymatic activity is required for this function. The present study demonstrates that prothrombin is also mitogenic for HVSMC due to the generation of enzymatically active thrombin which occurs upon incubation of prothrombin with the cells. Analysis by SDS‐PAGE, immunoblotting, and amino acid sequencing revealed that prothrombin incubated with HVSMC undergoes limited proteolysis. Prethrombin 1 was formed through cleavage at R155‐S156. Cleavage at R271‐T272 generated fragment 1.2 and prethrombin 2 whilst cleavage at R284‐T285 yielded truncated prothrombin 2 (prethrombin 2′). However, cleavage at R320‐I321 which, during prothrombin activation produces two‐chain α‐thrombin, was not detectable. Studies on HVSMC‐conditioned medium revealed that a similar pattern of prothrombin cleavage occurred by a cell‐secreted factor(s). Amidolytic activity analysis indicated that 1–3% catalytically active thrombin‐like activity was generated upon incubation of prothrombin with HVSMC‐conditioned medium. By treating conditioned medium with various classes of proteinase inhibitors or hirudin, it was determined that prothrombin is cleaved by a cell‐derived serine proteinase‐like factor(s) at R271‐S272 and by α‐thrombin at R155‐S156 and R284‐T285. Antibodies neutralising the activity of either urokinase, tissue plasminogen activator, or factor Xa failed to alter the prothrombin cleaving activity of conditioned medium. This activity which may catalyse an alternative pathway for the generation of thrombin, was eluted from a gel filtration column as a single peak with apparent molecular mass of 30–40 kDa. © 1995 Wiley‐Liss, Inc.
Retrovirally mediated wild‐type p53 restores S‐phase modulation without inducing WAF1 mRNA in breast carcinoma cells containing mutant p53
Authors: Runnebaum Ingo B. , Wang Shan , Kreienberg Rolf 
Published: May 2005

AbstractThe mechanism of negative growth regulation by the nuclear phosphoprotein p53 in breast cancer cells may rely on its role as a transcriptional activator of cell cycle‐related genes. We have tested this hypothesis using retrovirally transduced wild‐type (wt) p53 in breast cancer cell lines containing homozygously endogenous mutant (mt) p53. Restoring the expression of wt p53, the percentage of cells in S phase was reduced, G1/S transition was slowed, and progression through S was restrained. The fraction of cells with a flattened “Cdk‐minus” phenotype increased 5‐ to 10‐fold. High constitutive mRNA expression of the cyclin‐Cdk inhibitor WAF1 in MDAMB231 cells was not induced upon restored wt p53 expression suggesting a p53‐independent pathway in the regulation of WAF1 mRNA expression. Wt p53 acted trans‐dominantly in the presence of accumulating mt p53 and installed a modulation of G1/S transition and S phase progression independent of WAF1 expression. © 1995 Wiley‐Liss, Inc.
Recovery of gold by electroless precipitation from acid solutions using polyaniline
Authors: Ting Y. P. , Neoh K. G. , Kang E. T. , Tan K. L. 
Published: May 2005

AbstractThe oxidation of the leucoemeraldine (LM) and emeraldine (EM) states of polyaniline (PAN) and the subsequent reprotonation and reduction of the nigraniline (NA) and pernigraniline (PNA) in acid gold solution were utilized for the spontaneous and sustained reduction of gold. The rate of Au reduction is strongly dependent on the intrinsic oxidation state of the polymer and the polymer surface area. The rate also increases with decreasing pH of the chloroauric solution to about pH ∼ 1. X‐ray photoelectron spectroscopic (XPS) results indicate that only elemental gold or Au(0) accumulates on the polymer surface. The N1s core‐level spectra of the protonated and base form of EM films after Au reduction confirm that the intrinsic structure of the polymer remains intact. The process, however, is limited by the decreasing effective surface area of the polymer due to Au deposition. The results indicate that an LM film accumulated up to five times its own weight of Au (Au/monomer mole ratio > 2) before the recovery rate was significantly retarded.
Use of capillary suction apparatus for estimating the averaged specific resistance of filtration cake
Authors: Lee Duu‐Jong , Hsu Yuan‐Hway 
Published: May 2005

AbstractA method for estimating the averaged specific resistance of filtration cake, which avoids the necessity of measuring the liquid invasion volume in capillary suction apparatus (CSA) experiments, is proposed. When insufficient slurry is used, the slurry will exhaust during an experiment and the curve of wet front radius versus time shows transition. The transition point shifts according to the slurry concentration, cake specific resistance and the CSA parameters. Based on the wet front radius and the capillary suction time (CST) of the transition point, the liquid saturation under the inner cylinder can be estimated and the averaged specific resistance of cake calculated without the liquid invasion volume data. The proposed method agrees well with vacuum filtration data.
Scale‐up of a cyclone bioreactor
Authors: Sheppard John D. , Marchessault Philippe , Whalen Thomas , Barrington Suzelle F. 
Published: May 2005

AbstractThe operation of a cyclone bioreactor differs from conventional stirred tanks since the agitation is accomplished by means of a pumped reciculation loop. Oxygen transfer can occur across the swirling gas—liquid interface in the cyclone or from bubbles entrained in the recirculation loop. A cyclone bioreactor was scaled‐up from a 1 dm3 bench top unit to a 75 dm3 Process Development Unit (PDU). A reduction in the aspect ratio was compensated for by extending the length of the recirculation loop and providing additional aeration. Performance of the two reactors for the production of microbial poly‐β‐hydroxybutyrate (PHB) was compared under various operation conditions. The culture used for PHB production was Alcaligenes eutrophus DSM 545, grown on a mineral salts medium limited by the supply of nitrogen. The levels of dissolved oxygen obtained in the PDU were strongly dependent on the location at which the air was introduced into the reactor. However, with aeration balanced between two injection points and a similar level of power input, 17 J s−1 dm−3, the PDU was able to provide at least as much oxygen transfer capability as the laboratory‐scale reactor. Under all conditions tested, the PHB accumulation by A. eutrophus was in excess of 80% of the biomass dry weight, although the yield on glucose was lower in the PDU than in the laboratory‐scale reactor.
Residence time distribution measurements in a pulsed baffled tube bundle
Authors: Ni Xiongwei 
Published: May 2005

AbstractExperimental flow pattern and associated residence time distribution measurements are reported for a tube bundle where periodic baffles and fluid oscillation may be present. When there is no fluid oscillation, high Reynolds number flow conditions are required to give sharp residence time distributions. When baffles are present, fluid oscillation can give sharp residence time distributions for modest low net flow Reynolds numbers. These observations extend our previous results and also show the viability of the system, for example in use as a reactor or heat exchanger where a multi‐tube configuration might be required.
Immobilization of an endopectinlyase on γ‐alumina: Study of factors influencing the biocatalytic matrix stability
Authors: Dinnella Caterina , Lanzarini Gaetano , Stagni Andrea , Palleschi Claudio 
Published: May 2005

AbstractEndopectinlyase (EC 4.2.2.10) from Aspergillus japonicus was immobilized on to γ‐alumina. Adsorption performed at pH 5·0 and a subsequent cross‐linking phase using 0·1% glutaraldehyde were the chosen immobilization conditions. The comparison between the main biochemical parameters of the immobilized and free form of the enzyme showed that the immobilization procedure used did not affect the enzyme biochemical properties. The interactions between the carrier and the enzyme are essentially secondary bonding. In fact they depend on the pH and on the presence of phosphate ions in the medium. A tentative chemical model of the biocatalytic matrix thus obtained is proposed.
A lysine sensor for process control
Authors: Siegler Klaus , Weber Bettina , Weber Ekkehard , Tonder Karin , Klingner Edith , Riechert Frank 
Published: May 2005

AbstractA lysine sensor for process control of lysine fermentation was developed based on a Clark‐type electrode in combination with L‐lysine‐α‐oxidase. The enzyme, isolated from Trichoderma viride, was immobilized between a cellulose and a polypropylene foil using a polyurethane resin. Lysine determinations were carried out in a flow‐through system as anodic measurements when H2O2 was measured and as chathodic measurements when the consumption of O2 was followed. The sensitivity of the sensor toward other amino acids was determined.
Residence time distribution in a packed bed bioreactor containing porous glass particles: Influence of the presence of immobilized cells
Authors: De Backer Luc , Baron Gino 
Published: May 2005

AbstractAn experimental investigation of the liquid phase residence time distribution (RTD) in a packed bed bioreactor containing porous glass particles is presented. For Re < 1, intraparticle forced convection is negligible and only diffusion, characterized by an effective diffusion coefficient, must be considered to describe the mass transfer process between the extraparticle and the intraparticle fluid phase. For Re > 1, the mass transfer rate becomes dependent on the liquid flow rate, indicating the existence of intraparticle convection. A model including axially dispersed flow for the external fluid phase and an ‘apparent’ effective diffusivity that combines diffusion and convection, predicts experimental RTD data satisfactorily. Yeast cells immobilized inside the porous glass beads did not affect the mass transfer rate at low biomass loading. At high biomass loading (0·02 g yeast cells g−1 carrier), the mass transfer rate between the extraparticle and intraparticle fluid phase was significantly decreased. Comparison of the RTD data from experimets performed in the presence and absence of cells in the external fluid phase revealed that the mass transfer rate is influenced by the cells immobilized inside the porous particles and not by the cells present in the external fluid phase.
Thermal properties of silicate esters
Authors: Alagar Muthu K. , Manohar Amsavel , Manohar Paramasivam 
Published: May 2005

AbstractFourteen dimethyldialkoxysilanes are prepared by reacting dimethyldichlorosilane with corresponding alcohols in the liquid phase. Their physicochemical properties are determined by standard methods and their tentative empirical formulae are elucidated. The thermal conductivity values of dimethyldialkoxysilanes are determined using a two slab guarded hot plate apparatus over a temperature range of 30–190°C. The thermal conductivity values of dimethyldialkoxysilanes calculated from empirical equations are found to vary from ‐14% to +19%. Because thermal conductivity is an important parameter in heat transfer calculations, and to minimise the deviation of the values, new equations involving easily measurable ultrasonic parameters have been formulated. The proposed equations have been tested for the series of dimethyldialkoxysilanes, tetraalkoxysilanes and polydimethylsiloxanes. The thermal conductivity values computed from the proposed equations are comparable with experimental thermal conductivity values. Further, an equation involving the calculation of thermal conductivity values at varying temperatures is also proposed.
Optimum conditions for the reactivity of chromium (III) salts on collagen in the solvent tanning process
Authors: Silvestre F. , Rocrelle C. , Rigal L. , Gaset A. 
Published: May 2005

AbstractThe reactivity of trivalent chromium salts towards collagen, the main protein in animal skins, was investigated in organic solvents on lamb skins of controlled water content. The optimal conditions were determined by experiment modelling. Complete exhaustion of the tanning baths, and much higher chromium binding was observed with this system than with traditional processes carried out in aqueous media.
Recovery of tartaric and malic acids from dilute aqueous effluents by solvent extaction technique
Authors: Malmary Guy , Vezier Annick , Robert Arlette , Molinier Jacques , Mourgues Jean , Conte Thierry 
Published: May 2005

AbstractSolvent extraction deserves consideration for the recovery of carboxylic acids from wastewater in order to clean up industrial effluents. Tartaric and malic acids are present in low concentration in the effluents of distilleries producing grape sugar. The separation of these acids from dilute aqueous solutions by the technique of dissociation–extraction employing respectively tributylphosphate dissolved in dodecane and triisooctylamine (tris‐(6‐methylheptyl)‐amine) dissolved in 1‐octanol as solvents was explored in this study. With a solvent ratio of 0·5 and a solvent containing 0·6 mole of triisooctylamine per dm3 of the triisooctylamine + 1‐octanol mixture, the best percentages of malic and tartaric acids recovered were respectively 92 mass% and 99 mass% relative to the quantities of these acids present in the initial aqueous solutions.
Mechanical control of foaming in tower reactors
Authors: Takesono Satoshi , Onodera Masayuki , Yamagiwa Kazuaki , Ohkawa Akira 
Published: May 2005

AbstractRotating‐disk mechanical foam‐breakers (MFRDs) were applied to the control of foaming in bubble column (BC) reactors containing complex solutions and biological media. The foaming behaviour of BCs and the foam‐breaking behaviour of MFRDs fitted to BCs were evaluated respectively from the changes in the liquid hold‐up in ascending foam, ϕb, and the required critical disk rotational speed, Nc, for foam‐breaking. The differences in ϕb and Nc, reflecting the difficulty or ease of foam‐breaking among the liquids, correlated well with differences in the foaming characteristic term, FCT, of respective liquids, which could be determined on the basis of the results measured in the experimental small foaming apparatus which were different from those measured in the gas‐bubbling apparatus employed in practice. The usefulness of the empirical correlations for the prediction of ϕb and Nc, which can be applied independently of the type and concentration of foaming liquid or their physical properties, was also demonstrated.
Production of cellulases from coconut coir pith in solid state fermentation
Authors: Muniswaran P. K. Ananda , Selvakumar Pitchaivelu , Charyulu N. C. L. Narasimha 
Published: May 2005

AbstractCoconut coir pith, available in abundance especially in tropical countries, was studied as a substrate for the production of cellulase[1,4(1,3;1,4)‐β‐D‐glucan 4‐glucanohydrolase, EC 3.2.1.4] and β‐D‐glucosidase(β‐D‐glucoside glucohydrolase, EC 3.2.1.21) in solid state fermentation. The effects of fermentation time, nutrient level, substrate particle size and inoculum size have been examined for optimal production of these enzymes by the fungal strain Aspergillus niger NCIM 1005. The highest filter paper activity (FPA) of 4.11 IU g−1, carboxyl methyl cellulose (CMCase) activity of 15·55 IU g−1 and cellobiase activity of 9·31 IU g−1 were obtained after 7 to 8 days of fermentation. Reese and Mandel's mineral solution in the substrate to mineral solution ratio of 1:10 (w/v) supported high cellulase and cellobiase activities. An inoculum size of 20–50% (v/v) based on the volume of mineral medium and substrate average particle size of 375 μm were optimum for enzyme production.
Investigation of the stability and selectivity of phenylalanine transport across a supported liquid membrane
Authors: Campbell Moray J. , Walter Robert P. , Knowles Christopher J. , Singleton Ray 
Published: May 2005

AbstractA supported liquid membrane system was investigated for the carrier mediated transport of phenylalanine to more fully understand the contradictory effects, described in the literature, of chloride ion concentration in the aqueous phases on the stability of the system. The role of the organic phase and its interaction with carrier and support material was considered. The carrier mediated transport was comparable to an enzyme mediated process. Kinetic studies were undertaken and the data interpreted in a manner appropriate to biological transport processes to consider the transport process at a molecular level. The system was shown to deviate from a direct 1: 1 exchange process between phenylalanine and chloride and had a high degree of selectivity with respect to phenylalanine.
Energetics of Pseudomonas cepacia G4 growth in a chemostat with phenol limitation
Authors: Solomon Bamidele O. , Posten Clemens , Harder Michael P. F. , Hecht Volker , Deckwer Wolf‐Dieter 
Published: May 2005

AbstractAnalysis of the growth of Pseudomonas cepacia G4 on phenol in continuous culture has been carried out. The data were checked for consistency using both available electron and carbon balances. Coupled with the covariate adjustment estimation technique, the best estimates for true biomass energetic yield, ηmax and maintenance, me, were obtained when the carbon dioxide measurements were excluded. However, upon making corrections to the gas measurements, the best estimates were the maximum likelihood estimates (MLE) based on the complete data. The method therefore allows discrimination to be made between data. Also, similar estimates were obtained using Pirt's model based on the Monod approach and a modified form based on substrate uptake rate being the limiting factor. For the aerobic growth of P. cepacia G4 on phenol, ηmax = 0·417 and me = 0·0513 h−1 were obtained when the CO2 data were excluded. When corrections were made to the gas measurements to take into account the dissolved CO2 and the effect of operating temperature, ηmax = 0·432 and me = 0·0684 h−1 were obtained. From the 95% confidence intervals, a maximum of about 38–47·5% of the energy contained in phenol is incorporated into the biomass while the balance (52·5–62%) is evolved as heat with only a little energy needed for the maintenance of the organism.
Kinetics of anaerobic digestion of soft drink wastewater in immobilized cell bioreactors
Authors: Borja R. , Banks C. J. 
Published: May 2005

AbstractA kinetic study of the anaerobic digestion of soft drink wastewater was undertaken, using bioreactors containing various suspended supports (bentonite, zeolite, sepiolite, saponite and polyurethane foam), on to which the microorganisms effecting the purification were immobilized. Assuming the overall anaerobic digestion process conforms to first‐order kinetics, the specific rate constants, K0, derived from the reactors with saponite and sepiolite (magnesium silicates) were approximately twice those from bentonite and zeolite (aluminium silicates) and almost five times higher than in the control reactor (without support); the polyurethane support showed an intermediate behaviour. The methanogenic activity increased linearly with COD load, with saponite and sepiolite supports showing the highest values. The average yield coefficient of methane was 325 cm3 CH4 STP g−1 COD and the percentage elimination of COD was 77·8%; these values were not significantly altered by the type of support used.