bluuebunny/crossref_metadata_2025_split huggingface dataset:
Relationships between translation of pro α1(I) and pro α2(I) mRNAs during synthesis of the type I procollagen heterotrimer
Authors: Hu Geng , Tylzanowski Przemyslaw , Inoue Hiroyuki , Veis Arthur 
Published: May 2005

AbstractFinal assembly of the procollagen I heterotrimeric molecule is initiated by interactions between the carboxyl propeptide domains of completed, or nearly completed nascent pro α chains. These interactions register the chains for triple helix folding. Prior to these events, however, the appropriate nascent chains must be brought within the same compartments of the endoplasmic reticulum (ER). We hypothesize that the co‐localization of the synthesis of the nascent pro α1(I) and pro α2(I) chains results from an interaction between their translational complexes during chain synthesis. This has been investigated by studying the polyribosomal loading of the pro α‐chain messages during in vitro translation in the presence and absence of microsomal membranes, and in cells which have the ability to synthesize the pro α1 homotrimer or the normal heterotrimer. Recombinant human pro α1(I) and pro α2(I) CDNAs were inserted into plasmids and then transcribed in vitro. The resulting RNAs were translated separately and in mixture in a cell‐free rabbit reticulocyte lysate ± canine pancreatic microsomes. Cycloheximide (100 μg/ml) was added and the polysomes were collected and fractionated on a 15–50% sucrose gradient. The RNA was extracted from each fraction and the level of each chain message was determined by RT‐PCR. Polysomes from K16 (heterotrimer‐producing), W8 (pro α1(I) homotrimer), and A2′ (heterotrimer + homotrimer) cells were similarly analyzed. Translations of the pro α1(I) and pro α2(I) messages proceeded independently in the cell‐free, membrane‐free systems, but were coordinately altered in the presence of membrane. The cell‐free + membrane translation systems mimicked the behavior of the comparable cell polysome mRNA loading distributions. These data all suggest that there is an interaction between the pro α chain translational complexes at the ER membrane surface which temporally and spatially localize the nascent chains for efficient heteromeric selection and folding. © 1995 Wiley‐Liss, Inc.
Stable overexpression of human HSF‐1 in murine cells suggests activation rather than expression of HSF‐1 to be the key regulatory step in the heat shock gene expression
Authors: Mivechi Nahid F. , Shi Xaio‐You , Hahn George M. 
Published: May 2005

AbstractTranscription of the heat shock genes is regulated by the activation of the heat shock transcription factor (HSF‐1). After heat shock, HSF‐1 forms oligomers and binds to the heat shock element (HSE), which consists of several repeats of NGAAN located in the promoter region of the heat shock genes. HSF‐1 is then phosphorylated, leading to the enhanced transcription of the heat shock genes likely by transactivation. We have stably overexpressed the human heat shock transcription factor‐1 (HSF‐1) in murine cells to investigate whether the regulation of the expression of the heat shock genes may partly reside at the level of HSF‐1 expression. Human HSF‐1 cDNA was cloned into a retroviral vector (pvhhsf‐1) and was overexpressed in a murine fibroblast cell line. The overexpressed human HSF‐1 is found in both the cytoplasm and nucleus of control cells but is translocated into the nucleus upon heat shock. Electrophoretic mobility shift analysis suggests that the human HSF‐1 has constitutive DNA binding ability and its DNA binding ability is increased upon heat shock. Cross‐linking experiments indicate that the overexpressed human HSF‐1 is mainly a monomer under control conditions and forms oligomers upon heat shock. Immunoblotting shows that the human HSF‐1 is phosphorylated upon heat shock and its apparent molecular weight is shifted up by at least 10 kDa. In spite of both the DNA binding ability and phosphorylation, the overexpression of human HSF‐1 does not increase the transcription of murine HSP‐70 mRNA or increase the synthesis of other HSPs after heat shock beyond that observed in control untransfected cells. An exception is the enhanced synthesis of a 47–50 kDa protein after heat shock and an apparent lack of induction of one HSP‐70 kDa species when the protein pattern is analyzed by isoelectric focusing. Interestingly, cells overexpressing human HSF‐1 show a 4‐fold increase in the basal expression of luciferase when the plasmids containing the human HSP‐70 promoter ligated to the luciferase reporter gene are transiently expressed in these cells. Murine cells overexpressing human HSF‐1 are more resistant to the cytotoxic effects of heat when compared to the control untransfected cells, but the kinetics of thermotolerance development and decay is similar between HSF‐1 transfected and untransfected cells. In conclusion, human HSF‐1 protein in murine fibroblasts is modified in a similar fashion as the endogenous mouse HSF‐1 after heat shock. However, the overexpression of HSF‐1 does not result in overproduction of heat shock proteins after heat shock, perhaps because these cells contain abundant amounts of endogenous HSF‐1. © 1995 Wiley‐Liss, Inc.
Antithetic effects of ryanodine and ruthenium red on osteclast‐mediated bone resorption and intracellular calcium concentrations
Authors: Ritchie Candace K. , Strei Theresa A. , Maercklein Peter B. , Fitzpatrick Lorraine A. 
Published: May 2005

AbstractIn the process of bone remodeling, osteoclasts are responsible for resorption of bone. High levels of intracellular calcium decrease the bone resorbing activity of osteoclasts and increase detachment of osteoclasts from the bone surface. The regulatory role of intracellular calcium in bone resorption is not clearly understood. To understand this phenomenon, we studied the effects of the intracellular calcium modulators ryanodine and ruthenium red on bone resorption using the disaggregated osteoclast pit assay. Changes in intracellular calcium concentrations after treatment with these compounds were detected with the fluoroprobe fura2. With ryanodine, a significant, dose‐dependent decrease in bone resorption was detected. This inhibition of bone resorption was reversible upon the removal of ryanodine. Ryanodine increased intracellular calcium concentrations, suggesting that the mechanism of inhibition by ryanodine was via alterations in intracellular stores of calcium. After treatment with ruthenium red, osteoclasts resorbed significantly more bone compared to vehicle‐treated cells. This increase in bone resorption correlated with a decrease in intracellular calcium concentrations. The addition of parathyroid hormone or ruthenium red to osteoclast cultures containing ryanodine did not attenuate the decrease in bone resorption caused by ryanodine, suggesting that the mechanism of ryanodine inhibition of bone resorption may involve the “locking” of a calcium channel in an open position. © 1995 Wiley‐Liss, Inc.
Effect of cell cycle on the regulation of the cell surface and secreted forms of type I and type II human tumor necrosis factor receptors
Authors: Pocsik Eva , Mihalik Rudolf , Penzes Maria , Loetscher Hansruedi , Gallati Harald , Aggarwal Bharat B. 
Published: May 2005

AbstractThe cell cycle has been shown to regulate the biological effects of human tumor necrosis factor (TNF), but to what extent that regulation is due to the modulation of TNF receptors is not clear. In the present report we investigated the effect of the cell cycle on the expression of surface and soluble TNF receptors in human histiocytic lymphoma U‐937. Exposure to hydroxyurea, thymidine, etoposide, bisbensimide, and democolcine lead to accumulation of cells primarily in G1/S, S, S/G2/M, G2/M, and M stages of the cell cycle, respectively. Whilie no significant change in TNF receptors occurred in cells arrested in G1/S or S/G2 stages, about a 50% decrease was observed in cells at M phase of the cycle. Scatchard analysis showed a reduction in receptor number rather than affinity. In contrast, cells arrested at S phase (thymidine) showed an 80% increase in receptor number.The decrease in the TNF receptors was not due to changes in cell size or protein synthesis. The increase in receptors, however, correlated with an increase in total protein synthesis (to 3.8‐fold of the control levels). A proportional change was observed in the p60 and p80 forms of the TNF receptors. A decrease in the surface receptors in cells arrested in M phase correlated with an increase in the amount of soluble receptors. The cellular response to TNF increased to 8‐ and 2‐fold in cells arrested in G1 and S phase, respectively; but cells at G2/M phase showed about 6‐fold decrease in response. In conclusion, our results demonstrate that the cell cycle plays an important role in regulation of cell‐surface and soluble TNF receptors and also in the modulation of cellular response. © 1995 Wiley‐Liss, Inc.
Conditional gene expression in secretory tissues and skin of transgenic mice using the MMTV‐LTR and the tetracycline responsive system
Authors: Hennighausen Lothar , Wall Robert J. , Tillmann Urich , Li Minglin , Furth Priscilla A. 
Published: May 2005

AbstractMolecular mechanisms of development and disease can be studied in transgenic animals. Controlling the spatial and temporal expression patterns of transgenes, however, is a prerequisite for the elucidation of gene function in the whole organism. Previously we reportted that mice carrying a tetR/VP16 hybrid gene (tTA), under the control of the hunman cytomegalovirus immediate early 1 (HCMV‐IE1) gene promoter, can be used to temporally activate the expression of transgenes under the control of a promoter containing tetop sequences. We now show that the MMTV‐LTR can be used to target expression of tTA to the epthelial cells of secretory organs and skin in transgenic mice. Notably, nearly uniform expression of a tetop‐lacZ transgene was found in seminal vesicle, salivary gland, and Leydig cells of mice carrying also the MMTV‐tTA transgene. More heterogeneous patterns of gene expression were observed in mammary epithelial cells and nasal cells of the epidermis. Different MMTV‐tTA lines had conparable tissue expression patterns. Transcriptional activation mediated by tTA was up to several hundred fold and it was abrogated after the administration of tetracycline. The MMTV‐tTA mice established in this work will be useful for experiments examining the roles of biological factors at defined developmental stages in the epithelial cells of salivary gland, seminal vesicle, mammary gland, and skin and the Leydig cells of testes in addition, in combination with the CRE/lox recombnation system, these mice will be useful to achieve gene deletions at defined time points in these organs. © 1995 Wiley‐Liss, Inc.
Enhanced removal of selected hydrocarbons from soil by Pseudomonas aeruginosa UG2 biosurfactants and some chemical surfactants
Authors: Scheibenbogen Karl , Zytner Richard G. , Lee Hung , Trevors Jack T. 
Published: May 2005

AbstractThe ability of rhamnolipid biosurfactants produced by Pseudomonas aeruginosa UG2 to wash a model hydrocarbon mixture from unsaturated soil columns was studied. Both aliphatic and aromatic hydrocarbons were effectively removed without soil clogging with non‐recirculating biosurfactant solutions. Recirculation of wash solutions did not substantially affect washing efficiency. Of the several chemical surfactants tested, only Triton X‐100 provided comparable hydrocarbon washing efficiency without soil clogging. The results suggest that UG2 biosurfactants have the potential for remediation of hydrophobic pollutants in unsaturated soil.
Natural zeolite utilisation in pollution control: A review of applications to metals' effluents
Authors: Kesraoui‐Ouki Sabéha , Cheeseman Christopher R. , Perry Roger 
Published: May 2005

AbstractThis paper assesses the potential of natural zeolite utilization as a low‐cost ion‐exchange and sorbent material in pollution control and recovery of metals. The improvement of the purity of natural zeolites coupled with their chemical modification capabilities in order to provide specific properties may provide a cost‐effective alternative for the treatment of heavy metal contaminated soil and water. The application of natural zeolites in industrial pollution control is becoming important and the level of technical effort is increasingly expanding. The extent of application is unlikely to be related solely to their low cost, but also to improved properties and performance characteristics, which will advance the practical implementation of natural zeolites' technology.
Convenience of immobilized Bacillus licheniformis α‐amylase as time—temperature‐integrator (TTI)
Authors: De Cordt Susanna F. , Hendrickx Marc E. , Maesmans Geert J. , Tobback Paul P. 
Published: May 2005

AbstractFor the immobilization of Bacillus licheniformis α‐amylase to porous glass beads, the performances of three possible linking agents, glutaric dialdehyde, benzoquinone and S‐trichlorotriazine were assessed in respect of the protein yield, the enzymic activity and the thermostability of the immobilized enzyme. These three properties are to be evaluated in view of the possible use of the enzyme preparations as time–temperature‐integrators (TTIs) for assessing the severity of heat pasteurization or sterilization processes of food or pharmaceuticals. All three linkers improved the enzymes's resistance to irreversible heat inactivation to a similar extent and in each case biphasic inactivation kinetics were observed, whereas the dissolved B. licheniformis α‐amylase showed a simple first order decay. The immobilization yield, measured as protein per carrier weight, did not differ markedly for the three linkers, although the enzymic activity of the glutaric dialdehyde‐linked enzyme was lower than that of the benzoquinone‐ and S‐trichlorotriazine‐linked preparations.
Electrolytic flotation of pyrite
Authors: Kydros Konstantine A. , Gallios George P. , Matis Konstantine A. 
Published: May 2005

AbstractElectrolytic flotation, a rather unconventional flotation technique used in effluent treatment, was investigated on pyrite; the process was enhanced by xanthate and also a cationic collector. This was then compared with classical floatability experiments. Zeta‐potential measurements, under similar pulp conditions, were carried out to explain the process mechanism. The mineral flotation behavior in the presence of common modifiers was also examined during electrolytic flotation. The latter produces fine gas bubbles, has favorable hydrodynamic conditions and assists in flocculation of particles prior to flotation, as shown.
A continuous reactor system for production of lactulose
Authors: Kozempel Michael , Kurantz Michael 
Published: May 2005

AbstractA continuous reactor process was developed to produce lactulose from lactose. A system of two CSTRs in series with a tubular finishing reactor gave conversion to lactulose of about 76%. The reactors ran at 71–75°C with a volumetric hold‐up in the CSTRs of 22·7 dm3 and in the tubular reactor of 2·6 dm3. Each CSTR had a nominal residence time of 44 min. The flow rate was 0·53 dm3 min−1.
The tularaemia vaccine
Authors: Sandström Gunnar 
Published: May 2005

AbstractTularaemia is a disease caused by the facultative intracellular bacterium Francisella tularensis. Vaccination resulting in protective immunity is induced by live vaccine only. Such vaccination can be performed by scarification utilizing the live vaccine strain of F. tularensis (F. tularensis LVS), which results in good but not complete protection. Humoral as well as cell‐mediated immunity are induced by vaccination and it has been shown that cell‐mediated immunity is a prerequisite for protection. Since the live vaccine strain is attenuated and the genetic background of attenuation is unknown it is important to consider process parameters so that the immunogenicity of the vaccine is preserved.
Performance of a high‐solids anaerobic digestion process under various ammonia concentrations
Authors: Kayhanian Masoud 
Published: May 2005

AbstractAmmonia is produced during anaerobic digestion of protein‐containing materials. While ammonia can be utilized by some members of the anaerobic population, excess ammonia can inhibit methanogenesis. High‐solids anaerobic digestion may be especially sensitive to the effects of ammonia overproduction. This study explored the performance of a pilot scale high‐solids anaerobic digestion process under various total ammonia nitrogen (TAN) concentrations. In general the high‐solids digester could operate up to 1000 mg dm−3 without any inhibitory effect. The digester performed best when it was operated at TAN concentrations in the narrow range of 600 to 800 mg dm−3.
Catalytic activity and kinetic study of cerium‐catalyzed syntheses of hydroxybenzaldehydes by oxygen oxidation. II
Authors: Yoshikuni Tadatsugu 
Published: May 2005

AbstractThe cerium‐catalyzed syntheses of hydroxybenzaldehydes from cresols by oxygen oxidation have been developed. When cerium catalysts four‐coordinated by hydroxo ligand was employed, the oxidation process required much less catalyst (0·5%), a shorter reaction time (5→2 h) and a lower temperature (120→40°C). The rate of two first‐order reactions increased by a factor of c. 106.
Continuous ethanol production from carob pod extract by immobilized Saccharomyces cerevisiae in a packed‐bed reactor
Authors: Roukas Triantafyllos 
Published: May 2005

AbstractThe continuous production of ethanol from carob pod extract by immobilized Saccharomyces cerevisiae in a packed‐bed reactor has been investigated. At a substrate concentration of 150 g dm−3, maximum ethanol productivity of 16 g dm−3 h−1 was obtained at D = 0·4 h−1 with 62·3% of theoretical yield and 83·6% sugars′ utilization. At a dilution rate of 0·1 h−1, optimal ethanol productivity was achieved in the pH range 3·5–5·5, temperature range 30–35·C and initial sugar concentration of 200 g dm−3. Maximum ethanol productivity of 24·5 g dm−3 h−1 was obtained at D = 0·5 h−1 with 58·8% of theoretical yield and 85% sugars′ utilization when non‐sterilized carob pod extract containing 200 g dm−3 total sugars was used as feed material. The bioreactor system was operated at a constant dilution rate of 0·5 h−1 for 30 days without loss of the original immobilized yeast activity. In this case, the average ethanol productivity, ethanol yield (% of theoretical) and sugars′ utilization were 25 g dm−3 h−1, 58·8% and 85·5%, respectively.
Extractive membrane bioreactors: A new process technology for detoxifying chemical industry wastewaters
Authors: Livingston Andrew G. 
Published: May 2005

AbstractThis paper describes an extractive membrane bioreactor developed to extract and biodegrade toxic organic pollutants present in chemical industry wastewaters. The technology is applicable to wastewaters emanating in organic synthesis operations which are not treatable by conventional ‘direct’ biological treatment due to extremes of pH, high salt contents, or otherwise hostile organic compositions, and also to wastewaters that contain volatile organic compounds. A laboratory scale prototype demonstrating the technology has been operated continuously over periods of several months, using industrially produced wastewaters. No pre‐conditioning or dilution of the wastewaters is necessary prior to treatment, which removes and destroys over 99% of the toxic organics present.
Isotherms of chemical adsorption of bases on solid catalysts for acidity measurement
Authors: Aguayo Andrés T. , Gayubo Ana G. , Ereña Javier , Olazar Martín , Arandes José M. , Bilbao Javier 
Published: May 2005

AbstractThe measurement of the adsorption equilibrium constants of the bases and the total mass of base adsorbed at 200°C are proposed as reproducible indices of average acidity strength and of total acidity of the solid, respectively. The adsorption of different bases (ammonia, n‐butylamine, tert‐butylamine, pyridine) in gas phase on solid acidic catalysts (silica–alumina and zeolite catalysts and a silica gel) has been studied, by applying the calorimetric method in flow regime through an isothermal bed of solid. Both the conditions under which the adsorption is exclusively chemical as well as those under which the adsorption is not limited by the internal diffusion of the base have been determined. For these acidity measurements tert‐butylamine behaves well and is an alternative base to ammonia.
Mathematical model for lactic acid production from lactose in batch culture: Model development and simulation
Authors: Amrane Abdeltif , Prigent Yves 
Published: May 2005

AbstractThe models available to describe lactic acid production do not seem to fit the experimental data very well, especially at the end of batch cultures. From a careful analysis of batch data, an unstructured model of the process has been derived, in which the specific growth rate variations and lactic acid concentration with time have been described by complemented logistic functions. Also, an additional term has been introduced into the Luedeking–Piret expression, taking into account the reduction in rate of lactic acid production observed at very low growth rate.
Saccharification of microcrystalline cellulose by cellulase of Morchella conica mushroom mycelium in comparison with a commercial cellulase
Authors: Manzoni Matilde , Cavazzoni Valeria 
Published: May 2005

AbstractA comparison was made of the hydrolysis of microcrystalline cellulose Avicel using the cellulolytic complex of the ascomycete Morchella conica and a commercial cellulase. An enzyme concentration of 1 U AVase mg−1 substrate gave the best results during the hydrolytic processes. At 24 h, the M. conica enzyme complex achieved 35.5% and the commercial cellulase 31·2% saccharification, with glucose 84·2% and 52% of the total reducing sugars liberated, respectively. The specific rates of hydrolyses were 0·77 and 0·14 h−1 for reducing sugars and 0·54 and 0·12 h−1 for glucose formation with M. conica and the commercial cellulase, respectively. At 96 h, the degree of saccharification reached 46% for M. conica and 49% for the commercial cellulase, with glucose 76·5% and 65·9% of the total reducing sugars liberated, respectively. Both the complexes were quite stable with a residual activity of 62% CMCase and 47% AVase for M. conica, and 74% CMCase and 57% AVase for the commercial cellulase at 96 h of hydrolysis. The qualitative analysis of the hydrolysis products by TLC indicated, for M. conica, an earlier appearance of cellobiose, which was quickly hydrolyzed to glucose.
Treatment of palm oil mill effluent by upflow anaerobic filtration
Authors: Borja Rafael , Banks Charles J. 
Published: May 2005

AbstractAn upflow anaerobic filter (23 dm3 working volume) was used for the treatment of palm oil mill effluent. The filter was continuously operated for 215 days with organic loads ranging from 1·2 to 11·4 kg of chemical oxygen demand per cubic metre per day and hydraulic retention times from 15 to 6 days. The overall substrate removal efficiency was very high, up to 90% and the filter effluent contained almost no suspended solids. For all runs, the operation of the filter exhibited good stability for acidity and alkalinity, indicating that the use of buffer solutions would not be required. The methane concentration in the biogas, whose production varied from 20 to 165 dm3 per day, was about 60%. Daily gas production varied in the range 0·69–0·79 dm3 per gram of chemical oxygen demand removed.