bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sea urchin zygote chromatin exhibit an unfolded nucleosomal array during the first S phase
Authors: Imschenetzky MaríA , Puchi Marcia , Gutiérrez Soraya , Montecino Martín 
Published: May 2005

AbstractTo investigate changes in chromatin organization associated with DNA replication during the first stages of development of the sea urchin Tetrapygus niger, we compared micrococcal nuclease (MNase) digestion patterns of chromatin from zygotes harvested during the first S phase and from unfertilized eggs. We observed that the majority of DNA fragments derived from MNase digested zygote nuclei were similar to or smaller than a mononucleosome, while those derived from unfertilized egg nuclei were larger (1,500 to 410 bp). This result indicates that in zygotes, where active DNA replication is occurring, the major chromatin fraction is represented as unfolded nucleosomes. In contrast, in unfertilized eggs chromatin appears to be organized into polynucleosomes. To determine if the unfolded structure of nucleosomes observed during S phase is related to the level of poly (ADP‐ribosylation) of cleavage stage (CS) histone variants, zygotes were treated with 20 mM 3‐Amino Benzamide (3 ABA) during the interval between 3 and 30 min post‐insemination (p.i.). This treatment with 3 ABA decreases the poly (ADP‐ribosylation) of CS histone variants and inhibits the first S phase in zygotes [Imschenetzky et al. (1991): J Cell Biochem 46:234–241; Imschenetzky et al. (1993): J Cell Biochem 51:198–205]. When the MNase digested patterns of chromatin from these 3 ABA treated and control zygotes were compared, we found that the unfolded structure of the nucleosomes remains unaltered by the inhibition of the poly (ADP‐ribose) synthetase with 3 ABA. This result indicates that the unfolded nucleosomal structure, particular to the chromatin of S phase zygotes, is not contemporaneous to DNA replication and is independent of the normal level of poly (ADP‐ribosylation) of CS histone variants. © 1995 Wiley‐Liss, Inc.
Human parathyroid hormone as a secretory peptide in milk of transgenic mice
Authors: Rokkones Erik , Fromm Sigurd H. , Kareem B. Najma , Klungland Helge , Olstad Ole K. , Høgset Anders , Iversen Jan , Bjøro Kristian , Gautvik Kaare M. 
Published: May 2005

AbstractIn a transgenic mouse model we have targeted the expression of recombinant human parathyroid hormone (hPTH) to the mammary gland yielding hPTH as a secretory, soluble peptide in milk. A 2.5 kb upstream regulatory sequence of the murine whey acidic protein (WAP) directed the expression of the hPTH cDNA in a fusion gene construct (WAPPTHSV2) containing the SV40 small t‐antigen intron and polyadenylation site in the 3′ end. Established lines of transgenic mice secreted hPTH to milk in concentrations up to 415 ng/ml. Recombinant hPTH recovered from the milk was purified by HPLC and shown to be identical to hPTH standard as analyzed by SDS‐PAGE followed by immunoblotting. Expression of the WAPPTHSV2 was limited to the mammary gland as analyzed by polymerase chain reaction (PCR) and Southern blot of reversed transcribed mRNA from different tissues. hPTH is an important bone anabolic hormone and may be a potentially important pharmaceutical for treatment of demineralization disorders such as osteoporosis. We present the transgenic animal as a possible production system for hPTH. © 1995 Wiley‐Liss, Inc.
Estrogen response in the hFOB 1.19 human fetal osteoblastic cell line stably transfected with the human estrogen receptor gene
Authors: Harris Steven A. , Tau Kimberly R. , Enger Robert J. , Toft David O. , Riggs B. Lawrence , Spelsberg Thomas C. 
Published: May 2005

AbstractThe gene coding for the human wild‐type estrogen receptor (ER) was stably transfected into the human fetal osteoblastic cell line hFOB 1.19, a clonal cell line which is conditionally immortilized with a temperature sensitive mutant of SV40 large T antigen (tsA58). Five subclones were obtained which express various levels of ER mRNA and protein. The subclone with the highest level of functional (nuclear bound) ER, hFOB/ER9, contained 3,931 (±1,341) 17β‐estradiol molecules bound/nucleus as determined by the nuclear binding (NB) assay. Using the dextran coated charcoal (DCC) method, the level of total cytosolic ER measured was 204 (±2) fmol/mg protein. This subclone was examined further for estradiol (E2) responsiveness. The ER expressed in hFOB/ER9 cells was shown to be functional using a transiently transfected ERE‐TK‐luciferase construct. Expression of luciferase from this construct increased ∼25‐fold in hFOB/ER9 cells following 10−9M E2 treatment. This effect on ERE‐TK‐luciferase expression was both dose and steroid dependant. Further, treatment of hFOB/ER9 cells with 10−9M E2 resulted in a 2.5–4.0‐fold increase in endogenous progesterone receptor (PR) levels detected by steroid binding assays, and a noticeable increase in both the A and B forms of PR by western blot assay. The establishment of this estrogen responsive human osteoblastic cell line should provide an excellent model system for the study of estrogen action on osteoblast function. © 1995 Wiley‐Liss, Inc.
Cpn60 is exclusively localized into mitochondria of rat liver and embryonic Drosophila cells
Authors: Martín Carmen San , Flores Ana I. , Cuezva Josí M. 
Published: May 2005

AbstractSeveral reports have claimed that the mitochondrial chaperonin cpn60, or a close homolog, is also present in some other subcellular compartments of the eukaryotic cell. Immunoelectron microscopy studies, using a polyclonal serum against cpn60, revealed that the protein is exclusively localized within the mitochondria of rat liver and embryonic Drosophila cells (SL2). Furthermore, no cpn60 immunoreactive material could be found within the nucleus of SL2 cells subjected to a 1 h 37°C heat‐shock treatment. In contrast to these findings, immunoelectron microscopy studies, using a cpn60 monoclonal antibody, revealed mitochondrial and extramitochondrial (plasma membrane, nucleus) immunoreactive material in rat liver cells. Surprisingly, the monoclonal antibody also reacted with fixed proteins of the mature red blood cell. The monoclonal antibody, as well as cpn60 polyclonal sera, only recognize mitochondrial cpn60 in Western blots of liver proteins. Furthermore, none of the cpn60 antibodies used in this study recognized blotted proteins from rat red blood cells. Therefore, we suggest that the reported extramitochondrial localization of cpn60 in metazoan cells may be due to cross‐reactivity of some of cpn60 antibodies with conformational epitopes also present in distantly related cpn60 protein homologs that are preserved during fixation procedures of the cells. © 1995 Wiley‐Liss, Inc.
Expression of lysyl oxidase from cDNA constructs in mammalian cells: The propeptide region is not essential to the folding and secretion of the functional enzyme
Authors: Kagan Herbert M. , Reddy Vemuri B. , Panchenko Maria V. , Nagan Narasimhan , Boak Andra M. , Gacheru Stephen N. , Thomas Kathleen M. 
Published: May 2005

AbstractRat aortic lysyl oxidase cDNA was expressed under a metallothionein promoter in Chinese hamster ovary cells using a dihydrofolate reductase selection marker. One methotrexate‐resistant cell line, LOD‐06, generated by transfecting with full‐length cDNA, yielded lysyl oxidase proteins consistent with the 50 kDa proenzyme and a 29 kDa mature catalyst. A second cell line, LOD32–2, was generated by transfection with a truncated cDNA lacking sequences which code for the bulk of the propeptide region. Both cell lines secreted apparently identical, 29 kDa forms of mature lysyl oxidase each of which catalyzed the deamination of human recombinant tropoelastin and alkylamines, consistent with the known specificity of lysyl oxidase. The secreted enzyme forms were inhibited by chemical inhibitors of lysyl oxidase activity, including β‐aminopropionitrile, phenylhydrazine, ethylenediamine, α,α′‐dipyridyl, and diethyl‐dithiocarbamate. Sensitivity to these agents is consistent with the presence of copper and carbonyl cofactors in the expressed enzymes, characteristic of lysyl oxidase purified from connective tissues. These results indicate the lack of essentiality of the deleted proprotein sequence for the proper folding, generation of catalytic function, and secretion of lysyl oxidase. © 1995 Wiley‐Liss, Inc.
Molecular cloning of a mouse epithelial protein‐tyrosine phosphatase with similarities to submembranous proteins
Authors: Hendriks Wiljan , Schepens Jan , Bächner Dietmar , Rijss Johan , Zeeuwen Patrick , Zechner Ulrich , Hameister Horst , Wieringa Bé 
Published: May 2005

AbstractProtein‐tyrosine phosphatases (PTPases) form an important class of cell regulatory proteins. We have isolated overlapping cDNA clones that together comprise an 8 kb transcript encoding a novel murine PTPase which is expressed in various organs. Sequence analysis revealed an open reading frame of 2,460 amino acid residues. The predicted protein, PTP‐BL, is a large non‐transmembrane PTPase that exhibits 80% homology with PTP‐BAS, a recently described human PTPase. PTP‐BL shares some intriguing sequence homologies with submembranous proteins. It contains a band 4.1‐like motif also present in the tumor suppressors neurofibromatosis 2 and expanded, five 80 amino acid repeats also present in the disc‐large tumor suppressor, and a single catalytic phosphatase domain. No obvious homologies to other proteins were found for the N‐terminal region of the protein other than human PTP‐BAS. RNA in situ hybridization experiments show that the PTP‐BL gene is expressed in epithelial cells, predominantly in kidney, lung, and skin. These data suggest a cell cortical localization for PTP‐BL in epithelial cells and a possible role in the morphology and motility of epithelial tissues. © 1995 Wiley‐Liss, Inc.
Facile optical resolution of amino acid esters via hydrolysis by an industrial enzyme in organic solvents
Authors: Kijima Tatsuro , Ohshima Kouji , Kise Hideo 
Published: May 2005

AbstractRacemic amino acid esters were optically resolved via hydrolysis in organic solvents by the catalysis of an industrial alkaline protease, “Alcalase”. The products which were composed mainly of L‐amino acids were insoluble and easily separated by filtration. The activity of the enzyme and enantiomeric excess of the products were significantly dependent on the nature of solvent and the water content in the reaction media. Generally, high values of enantiomeric excess were obtained at low water contents. Many natural and unnatural amino acids were resolved by this method.
Study on the properties of iron–cobalt alumina supported catalyst for ammonia
Authors: Kaleńczuk Ryszard J. 
Published: May 2005

AbstractThe addition of Co to Fe/Al2O3 increases the catalytic activity in NH3 synthesis. The maximum effect is observed for 20% by weight of Co in the metallic phase. Bivalent cobalt atoms replace bivalent iron atoms (a similar ionic radius) in the crystal lattice. This process changes the reducibility of the samples. The Fe‐Co compound and its formation results in the fairly high temperature of reduction (873 K) which is needed to prepare the most active catalyst. Changing the reactor atmosphere from reducing to inert causes the disappearance of free iron (escape of Fe to the crystal lattice of support with formation of a new compound with a spinel character). This is the effect of the iron‐hydrogen interaction. The formation of an intermetallic iron‐cobalt compound is crucial to the catalyst activity. This might be due to the surface restructuring by exposing the most active iron surface, Fe(111). The potassium addition in the form of KOH causes an increase in the catalytic activity. The increase is not as high as for a ‘super basic’ Fe‐Co magnesium hydroxide carbonate supported catalyst studied earlier. A part of the potassium hydroxide is used to neutralize the acid sites on the surface of alumina.
Kinetics of the liquid phase synthesis and hydrolysis of butyl lactate catalysed by cation exchange resin
Authors: Dassy Stephane , Wiame Hughes , Thyrion Fernand C. 
Published: May 2005

AbstractEsterification of lactic acid with butanol catalysed by cation‐exchange resin was carried out in a batch reactor in dioxane and toluene. The reaction rate was found to be first order with respect to catalyst and acid concentrations. The inhibiting effect of water and butanol has been evaluated. The rate data were correlated with a kinetic model based on inhibition by water and butanol.
Cementitious mixtures containing industrial process wastes suitable for the manufacture of preformed building elements
Authors: Beretka Julius , Cioffi Raffaele , Santoro Luciano , Valenti GianLorenzo 
Published: May 2005

AbstractMixtures made from materials containing reactive oxides of calcium, aluminium, sulphur and silicon which are able, upon hydration, to generate calcium trisulphoaluminate and silicate hydrates, have been studied with a view to possible applications in the field of preformed building elements. The materials employed were natural gypsum, phosphogypsum, fly ash, blast furnace slag, Portland cement and hydrated lime. The samples were cured at 55, 70 and 85°C and 100% RH for 24 h, followed by further curing at ordinary temperatures and humidities (21°C, 67% RH) for up to 28 days. The cured samples were tested for compressive strength and shrinkage. It has been found that the most important effect on the strength is due to the pre‐curing temperature, while the post‐curing time has much less effect. In general, the optimum pre‐curing temperature is 70°C. Satisfactory strength results were obtained even with systems containing up to 80% waste materials.
Asymmetric reduction of prochiral ketones by cell‐free systems from alcaligenes eutrophus
Authors: Madyastha Kattigere M. , Gururaja Tarikere L. 
Published: May 2005

AbstractA strain of Alcaligenes eutrophus has been isolated from the soil by enrichment culture technique with nerolidol (1), a sesquiterpene alcohol, as the sole source of carbon and energy. Fermentation of nerolidol (1) by this bacterium in a mineral salts medium resulted in the formation of two major metabolites, viz. geranylacetone (2) and an optically active alcohol, (S)‐(+)‐geranylacetol (3). Nerolidol (1)‐induced cells readily transformed 1,2‐epoxynerolidol (4) and 1,2‐dihydroxynerolidol (5) into geranylacetone (2). These cells also exhibited their ability to carry out stereospecific reduction of 2 into (S)‐(+)‐geranylacetol (3). Oxygen uptake studies clearly indicated that nerolidol‐induced cells oxidized compounds 2, 3, 4, 5 and ethyleneglycol (7). Based on the nature of the metabolites isolated, the ability of nerolidol‐induced cells to convert compounds 4 and 5 into geranylacetone (2), and oxygen uptake studies, a pathway for the microbial degradation of nerolidol (1) has been proposed. The proposed pathway envisages the epoxidation of the terminal double bond, opening of the epoxide and cleavage between C‐2 and C‐3 in a manner similar to the periodate oxidation of cis‐diol. The cell‐free extract prepared from nerolidol‐induced cells readily carried out the asymmetric reduction of compound 2 to an optically active alcohol (3) in the presence of NAD(P)H. The cell‐free extract carried out both oxidation and reduction reactions at two different pH values and exhibited wide substrate specificity towards various steroids besides terpenes.
New strategies for the Hofmann reaction
Authors: Rane Dhananjay S. , Sharma Man M. 
Published: May 2005

AbstractSome new strategies, such as the use of hydrotropes, surfactants, co‐solvent, etc., were applied to the Hofmann reaction of fatty amides to obtain isocyanates, amines and carbamates. Additionally, some industrially important aromatic amines were synthesised.
Adsorption of cadmium and zinc from aqueous solution on natural and activated bentonite
Authors: Pradas E. González , Sánchez M. Villafranca , Cruz F. Cantón , Viciana M. Socías , Pérez M. Fernández 
Published: May 2005

AbstractThe adsorption of cadmium and zinc ions on natural bentonite heat‐treated at 110°C or at 200°C and on bentonite acid‐treated with H2SO4 (concentrations: 0·5 mol dm−3 and 2·5 mol dm−3), from aqueous solution at 30°C has been studied. The adsorption isotherms corresponding to cadmium and zinc may be classified respectively as H and L types of the Giles classification which suggests the samples have respectively a high and a medium affinity for cadmium and zinc ions.The experimental data points have been fitted to the Langmuir equation in order to calcualte the adsorption capacities (Xm) and the apparent equilibrium constants (Ka) of the samples; Xm and Ka values range respectively for 4·11 mg g−1 and 1·90 dm3 g−1 for the sample acid‐treated with 2·5 mol dm−3 H2SO4 [(B)‐A(2·5)] up to 16·50 mg g−1 and 30·67 dm3 g−1 for the natural sample heat‐treated at 200°C [B‐N‐200], for the adsorption process of cadmium, and from 2·39 mg g−1 and 0·07 dm3 g−1, also for B‐A(2·5), up to 4·54 mg g−1 and 0·45 dm3 g−1 [B‐N‐200], for the adsorption process of zinc. Xm and Ka values for the heat‐treated natural samples were higher than those corresponding to the acid‐treated ones. The removal efficiency (R) has also been calculated for every sample; R values ranging respectively from 65·9% and 8·2% [B‐A(2·5)] up to 100% and 19·9% [B‐N‐200], for adsorption of cadmium and zinc.
An on‐line respirographic biosensor for the characterization of load and toxicity of wastewaters
Authors: Vanrolleghem Peter A. , Kong Zaide , Rombouts Guido , Verstraete Willy 
Published: May 2005

AbstractA respirographic biosensor is presented that is capable of monitoring the waste load and potential toxicity of wastewaters, both off‐line in a laboratory or on‐line at the wastewater treatment plant. The principles of the sensors' operation have been developed and implications of the design choices evaluated. Short term BOD values were obtained every 30 min. The linear dynamic range spanned concentrations differing by a factor of 5000. This range could be expanded by a factor of 10 by adjusting the aeration rate of the bioreactor in the sensor. The response time for toxicity detection was approximately 1 h. The use in the sensor of activated sludge from the plant concerned ensured relevant toxicity information was obtained. To check the condition of the sludge, an independent respiration measurement is proposed. When a siginificant activity change is observed, the sludge in the sensor must be replaced. The presence of oxidoreduction chemicals can cause interferences that may lead to measurement errors. Based on a difference in reaction kinetics, their presence can be assessed and the effect eliminated. Both on‐line and laboratory applications in the chemical industry are presented. Special emphasis is given to the usefulness of the sensor data for waste management of production divisions. On‐line assessment of load variations and hydrogen peroxide spills are given as illustrations of the implementation of the sensor on the treatment plant. Attention is drawn to the potential application of the data for process control and improved performance of the treatment plant.
Purification of nickel sulphate solutions containing iron, copper, cobalt, zinc and manganese
Authors: Senapati Debasis , Chaudhury G. Roy , Sarma P. V. R. Bhaskara 
Published: May 2005

AbstractAcidic nickel‐bearing solution containing iron, cobalt, manganese, zinc and copper was processed through a solvent extraction and precipitation technique to obtain a pure nickel sulphate solution. Iron was extracted using 0.2M Cyanex‐272 (partially neutralised) as the extractant. Stripping of iron from the loaded organic has also been studied. After iron recovery through solvent extraction the raffinate still contained 0·25 g dm−3 of iron which was quantitatively separated by a lime precipitation technique. During this iron precipitation there was no loss of cobalt and nickel but copper, manganese and zinc were coprecipitated to some extent. From the iron‐free nickel sulphate solution the other impurities were extracted using the same extractant (Cyanex‐272) in a single stage. The metal ions from the loaded organic were stripped using a 0·5% (v/v) H2SO4 solution in a single stage. The entire operation needs only seven stages: two stages for iron extraction, three stages for iron stripping from the loaded organic, and one stage each for extraction and stripping of other impurities. In the entire operation the loss of nickel was less than 0·5%.
Pectinlyase immobilization on polyamides for application in the food processing industry
Authors: Spagna Giovanni , Pifferi Pier G. , Tramontini Maurilio , Albertini Alberto 
Published: May 2005

AbstractThe study concerns the immobilization of a pectinlyase (PL, EC 4.2.2.3) purified by means of a commercial enzyme for its possible applications in fruit juice and beverage processing. Results previously obtained were improved by employing polyamides, i.e. nylon 6 and nylon 11, activated by easy to perform and inexpensive methods such as direct activation with glutaraldehyde and alkylation with dimethylsulphate followed by treatment with amines and glutaraldehyde. The nylon 6 activated with glutaraldehyde gave an activity of the immobilized PL of about 200 U g−1 (at optimum pH) and a half‐life of about 190 h (at pH 3·3 and 25°C).
Kinetics of zinc adsorption on charcoal
Authors: Mishra S. Prabha , Chaudhury G. Roy 
Published: May 2005

AbstractThe kinetics of zinc adsorption on charcoal was carried out. In order to study the kinetics of adsorption various parameters were studied such as pH, particle size of charcoal, temperature, amount of charcoal as well as initial Zn2+ ion concentration. The adsorption kinetics followed a Freundlich adsorption isotherm. Good correlation of the theoretical and experimental equilibrium concentrations of Zn2+ ions was observed for the isotherm model. A mathematical model was developed to explain the kinetic data. The rate determining step for adsorption was found to be diffusion controlled.
Penicillin G extraction from model media using an emulsion liquid membrane: A theoretical model of product decomposition
Authors: Lee Kwi Ho , Lee Sang Cheol , Lee Won Kook 
Published: May 2005

AbstractTo confirm the applicability for the extraction of penicillin G by an emulsion liquid membrane (ELM), the degree of decomposition of penicillin G during extraction was theoretically calculated. Decomposition was less than 1% provided that the initial sodium carbonate concentration in the internal phase was correctly determined, which proved the applicability of the ELM process. The procedure to determine the initial carbonate concentration in the internal phase was also described in order that the pH in the internal phase should be within the relatively stable range for penicillin G at the end of the extraction.
Penicillin G extraction from model media using an emulsion liquid membrane: Determination of optimum extraction conditions
Authors: Lee Kwi Ho , Lee Sang Cheol , Lee Won Kook 
Published: May 2005

AbstractPenicillin G extraction by an emulsion liquid membrane (ELM) was investigated. The effects of surfactants, diluents, and carrier mixtures, together with their combined effects on the initial extraction rate and the emulsion stability were examined. Surfactants, diluents, and carriers used were Span80 (sorbitan monooleate)/ECA4360J (nonionic polyamine),n‐butyl acetate/kerosene, and DOA (dioctylamine)/Amberlite LA‐2 (secondary amine), respectively. The optimum extraction conditions were found to be 20% (v/v) of Span80 in ECA4360J as a surfactant, kerosene as a diluent and Amberlite LA‐2 as a carrier.