bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparison of the heparanase enzymes from mouse melanoma cells, mouse macrophages, and human platelets
Authors: Graham Lloyd D. , Underwood P. Anne 
Published: July 2007

AbstractThe intracellular heparanases from mouse macrophage and melanoma cells are very similar in terms of their size (60‐80 kDa), pI (5.3‐4.1), pH optimum (<‐5.5), and interactions with heparin. These proteins are therefore likely to be identical, suggesting that tumour and blood cells utilise the same heparanase enzyme. The human platelet enzyme is similar to the mouse enzymes in terms of pH optimum (č‐5.5) and pI value (5.3‐4.8), but appears to be smaller in size (40‐60 kDa). It also seems to differ from the mouse enzymes in aspects of its surface charge, and in its interactions with heparin. There was no indication that proteolysis was of significance for the enzymes, nor that they contained any sialic acid residues.
Isolation of a developmentally‐regulated expressed sequence tag from bladder tissue using the mRNA differential display
Authors: Chaqour Brahim , Howard Pamela S. , Macarak Edward J. 
Published: July 2007

AbstractIn order to gain insight into the molecular and cellular events that govern the structural and the functional properties in developing organs, we have conducted a study to identify genes that have a temporally‐restricted expression in the bladder wall during fetal development. We utilized the mRNA differential display technique and compared the pattern of gene expression during the first, the second and the third trimester of gestation. We cloned and sequenced a cDNA fragment (bld‐10) which was expressed during the second and third trimester but consistently absent during the first trimester. The bld‐10 sequence is not related to any known gene in the GenBank database but has significant homology (89%) with human expressed sequence tag (EST) that has been cloned from human fetal heart and brain libraries. When used in Northern‐blot hybridization as a probe, the fragment bld‐10 generates two hybridization signals of 3.1 and 4.0 kb, that are minimally expressed during the first trimester of gestation and up‐regulated in the second and third trimester. Differential expression of this gene may be responsible for some of the profound changes which occur during organ development.
Identification and characterization of a mitochondrial endonuclease from yeast, Schizosaccharomyces pombe
Authors: Ikeda Shogo , Maeda Noriaki , Ohshima Tomoaki , Takata Norifumi 
Published: July 2007

AbstractSchizosaccharomyces pombe mitochondria were isolated from the cells treated with Novozyme 234, and purified in a Percoll gradient. A zymographic assay in a SDS‐polyacrylamide gel containing single‐stranded DNA revealed that an endonuclease of 32 kDa is associated with the mitochondria. The endonuclease was extracted from the mitochondria with 0.5 M KCI and was partially purified. The 32‐kDa enzyme degraded both DNA and RNA at a weak alkaline pH, but preferred single‐stranded DNA. The enzyme required Mg2+ or Mn2+, but not Ca2+ or Zn2+ for activity, and was inhibited by 50% with a 150 mM salt solution. Nicks generated by the enzyme could be resealed with T4 DNA ligase, indicating that the enzyme produces 5′‐P and 3′‐OH ends.
Modification of Tyrosine‐3 (63) and Lysine‐6 of Taiwan cobra phospholipase A2 affects its ability to enhance 8‐Anilinonaphthalene‐1‐sulfonate fluorescence
Authors: Chang Long‐sen , Lin Shinne‐ren 
Published: July 2007

AbstractThe Tyr‐3 (63) and Lys‐6 of Naja naja atra phospholipase A2 (PLA2) were modified with p‐nitrobenzenesulfonyl fluoride and 4‐chloro‐3,5‐dinitrobenzoate, respectively. Although the ability of the Lys‐modified derivative to enhance the ANS fluoresence was lower than that observed with native PLA2, the ANS‐binding affinity of the Lys‐modified derivative was similar to that of the native enzyme. Modifications on Tyr‐3 or/and Tyr‐63 of PLA2 resulted in the complete loss of its ability to enhance the ANS fluorescence. Nevertheless, the extent of O‐sulfonylation of Tyr residues was not effectively reduced by the addition of ANS. This suggests that Tyr‐3 and Tyr‐63 interact with the bound ANS in an aromatic ring‐stacking manner. Alternatively, the incorporation of a carboxydinitrophenylated group on Lys‐6 may notably perturb the nonpolarity of the ANS‐binding site.
Structure of bacteriochlorophyll aggregates in chlorosomes of green bacteria: A spectral hole burning study
Authors: Novoderezhkin Vladimir I. , Fetisova Zoya G. 
Published: July 2007

AbstractExciton level structure, homogeneous absorption and hole‐burning spectra were calculated for different models of bacteriochlorophyll aggregation in chlorosomal antennae of green bacteria. It was demonstrated that none of the earlier proposed models of noninteracting linear bacteriochlorophyll aggregates and linear bacteriochlorophyll chains assembling in tubular aggregates with high density of packing, exhibits the in vivo exciton level structure revealed by hole‐burning experiments on intact cells of green bacteria. The models of linear exciton‐coupled bacteriochlorophyll chains with a low packing density, approximating that in vivo, were proposed as alternative, to obtain the main spectral features found in natural antennae.
Protein kinase C inactivation by Fenton's‐reaction at discrete CU binding sites
Authors: Traverso Nicola , Ricciarelli Roberta , Domenicotti Cinzia , Menini Stefano , Pronzato M. Adelaide , Cottalasso Damiano , Marinari Umberto M. 
Published: July 2007

AbstractThe consequence of direct exposure to HO radical (chemically generated by Fenton's reaction) of partially purified rat liver PKC has been evaluated in this work. PKC inhibited Fenton‐dependent HO generation, probably due to the binding of copper ions to the enzyme. PKC activity was inhibited by H2O2. Copper ions were able to increase the H2O2‐mediated damage to the enzyme, but only beyond a concentration threshold.The possible interactions between PKC and Fenton's reagents, in particular copper ions, is discussed.
Activation of cathepsin D by polyanionic compounds
Authors: Watabe Shoji , Ikeda Tadao , Yago Nagasumi 
Published: July 2007

AbstractWe examined the nature of the activation of cathepsin D by polyanionic compounds. Tripolyphosphate, a model compound for polyanions, decreased the Km value of porcine cathepsin D for bovine serum albumin without affecting Vmax. Half‐maximal activation was achieved at 0.2 mM free tripolyphosphate. Electrophoretic mobility of cathepsin D decreased as the tripolyphosphate concentration was increased, and the enzyme had no net charge at 50 mM triP. The concentration for the half‐maximal mobility change of cathepsin D (0.18 mM) was similar to that for half‐maximal activation. These results suggest that tripolyphosphate increased affinity of the enzyme for its substrate by cancelling positive charges on cathepsin D and thus decreasing the electrostatic repulsion.
Expression of catalytically active human multifunctional glycogen‐debranching enzyme and lysosomal acid alpha‐glucosidase in insect cells
Authors: Wu Jer‐Yuarn , Van Hove Johan L. K. , Huang Yuan‐Sheng , Chen Yuan‐Tsong 
Published: July 2007

AbstractGlycogen debranching enzyme and acid α‐glucosdase are responsible for glycogen degradation in human. The formal enzyme is a mulifunctional enzyme with two independenent catalytic activities occuring on a single polypeptide, while the latter is a lysosomal enzyme which matures through extensive glycosylation and phosphorylation and proteolytic processing. Deficiency of glycogen debranching enzyme and acid α‐glucosidase cause glycogen storage disease type III and II, respectively. Baculovirus/insect expression system was used to produce both GDE and GAA. Both enzymes were found to be catalytically and antigenically active. The majority of recombinant GDE is present in the medium (70%). Uptake experiment indicated that GAA produced in the insect cells could not be absorbed into the GSD type II patient fiboblasts through mannose‐6‐phosphate receptor mediated endocytosis. Uptake experiment combined with immunoblot analysis indicated there are differences in the posttranslational modification and processing between insect cells and mammalian cells.
Identification of a Zn2 ‐sensitive component of Ehrlich cell plasma membrane redox system by CHAPS‐agarose‐polyacrylamide electrophoresis and in situ staining of activity
Authors: Rodríguez‐Caso Luis , Rodríguez‐Agudo Daniel , Castillo‐Olivares Antonio del , Márquez Javier , de Castro Ignacio Núñez , Medina Miguel Ángel 
Published: July 2007

AbstractA procedure based on CHAPS‐agarose‐polyacrylamide electrophoresis and in situ staining of activity was used to detect a Zn2+‐sensitive component of Ehrlich cell plasma membrane redox system. The procedure is so powerful that it allows to use crude plasma membrane fractions and can be easily adapted for use in an electrophoretic approach to the purification of this protein.
Essential fatty acid metabolism in cardiomyocytes grown in media enriched with different N‐6/N‐3 fatty acid combinations
Authors: Hrelia Silvana , Biagi Pier L. , Lorenzini Antonello , Jimenez Josè A. Lopez , Horrobin David F. , Bordoni Alessandra 
Published: July 2007

AbstractWe have evaluated the effects of three different 18:3n‐6, 20:5n‐3 and 22:6n‐3 fatty acid combinations on essential fatty acid (EFA) metabolism in rat cultured cardiomyocytes. The desaturating/elongating activities for linoleic (LA) and α‐linolenic acid (ALA) were evaluated by radlolabehng the cells with 1‐[14C]LA or 1‐[14C]ALA and the fatty acid pattern of cardiomyocytes was assessed by gas chromatography. LA and ALA conversion to more unsaturated metabolites was reduced by increasing respectively n‐3 and n‐6 fatty acid concentration in the media. The all three combinations used reduced the saturated and increased the polyunsaturated fatty acid content of cardiomyocytes. The n‐6/n‐3 fatty acid ratio did not change compared to control cells in cardiomyocytes receiving the highest amount of 18:3n‐6 and the lowest amounts of n‐3 fatty acids This combination may be suitable for modifying EFA desaturating/elongating activities without altering the physicochemical parameters which are related to the correct balance between n‐6 and n‐3 fatty acid content.
Cytokine profile in autosomal dominant polycystic kidney disease
Authors: Merta M. , Tesař V. , Zima T. , Jirsa M. , Ryšavá R. , Žabka J. 
Published: July 2007

AbstractTo elucidate the pathogenetic mechanism of renal parenchymal injury in autosomal dominant polycystic kidney disease (ADPKD) patients, typically characterized by renal cystic changes paralleled by interstitial inflammation and gradual fibrotic changes, the role of selected inflammatory mediators was evaluated in a group of ADPKD patients with normal glomerular filtration rate. The plasma concentrations of IL‐6, IL‐8, ICAM‐1 and VCAM‐1 (which may reflect systemic response to inflammation/infection) were increased in the ADPKD patient group. Coupled with decreased urinary excretion of the IL‐1 receptor antagonist (which exerts an anti‐inflammatory role), these results suggest that even in overt infection free status, the proinflammatory system is more activated and anti‐inflammatory defence system weakened in ADPKD subjects. Our data support the current view that cytokines are candidate contributors to pathogenesis of ADPKD.
Adsorption of Bacillus subtilis endo‐β‐1,4‐glucanase to cellulosic materials
Authors: Kim Hoon , Ahn Dong Ho , Jung Kyung Hwa , Pack Moo Young 
Published: July 2007

AbstractThe intact and the truncated endo‐β‐1,4‐glucanase expressed in Bacillus megaterium by a B. subtilis gene were purified and its adsorption characteristics to cellulosic materials were investigated. The intact enzyme was purified by affinity towards insoluble cellulose and Mono‐Q chromatography. The truncated enzyme was purified by gel filtration and chromatofocusing. The molecular activities of these enzymes towards the soluble substrates were identical. Optimum pH and temperature of these two types of enzyme were same, 5.5 and 60°C, respectively. However, the insoluble substrate, Avicel, was hydrolyzed slowly by the intact endoglucanase while the truncated endoglucanase did not hydrolyze the Avicel. Isoelectric points of the intact and the truncated enzyme were 6.2 and 5.6, respectively. In a Sephadex column the large form of intact endoglucanase was eluted later than the small form of truncated enzyme. Only the intact enzyme was strongly adsorbed to Avicel. The practical maximum adsorption was about 20 mg/g of Avicel at pH 6.0 and 4°C.
Inositol 1,4,5‐Trisphosphate distribution in Lycopersicon esculentum mill. seedlings cultivated “in vitro” under different conditions
Authors: Piacentini Maria Piera , Ricci Donata , Fraternale Daniele , Piatti Elena , Manunta Antonio , Accorsi Augusto 
Published: July 2007

AbstractMeasurements of inositol 1,4,5‐trisphosphate (Ins 1,4,5‐P3 in cotyledons, epicotyls and roots of tomato seedlings grown “in vitro” either in the light or in the dark indicated that higher concentrations of this signal‐transducing molecule are contained in hypogeous vs. epigeous tissues. The same was observed in induced cotyledon explants grown in the light in the presence of growth regulators. Data concerning phosphatidylinositol metabolism in seedling roots are also reported. Taken together, our results may be helpful in understanding the role of the polyphosphoinositide signal system in plants.
Isolation and characterization of isoforms of retinol binding protein by isoelectrofocusing
Authors: Minic Zoran , Hranisavljevic Jovan , Vucelic Dusan 
Published: July 2007

AbstractRetinol binding protein prepared from human urine was fractionated by chromatofocusing into four isoforms: two retinol‐containing (holo‐) and two retinol‐free (apo‐) species. The pI values of the isoforms ascertained by isoelectrofocusing with an immobiline pH gradient were: holo(I) 4.79‐4.77; apo(II) 4.61‐4.56; holo(III) 4.63 and apo(IV) 4.46‐4.41. In vitro aging experiments with apo(II) under conditions favoring deamidation (37°C, pH 7‐10, 3‐28 days) resulted in formation of the more acidic apo(IV)‐isoform. The aging rate was consistent with pH increase. It appears that the urinary RBP mixture is composed of two apo‐holo pairs: a native form with genuine protein structure and an acidic form generated upon aging.
D‐glucose metabolism in dimethyl suberimidate‐treated tumoral pancreatic islet cells
Authors: Vanhoutte C. , Malaisse W. J. 
Published: July 2007

AbstractAfter protein cross‐linking by dimethyl suberimidate, tumoral insulin‐producing cells of the RINm5F line were either exposed to digitonin for measurement of hexokinase activity in the resulting cell pellet and supernatant, or incubated in the presence of D‐[5‐3H]glucose, D‐[U‐14C]glucose or L‐[U‐14C]glutamine to assess the metabolism of these nutrients. After digitonin treatment, the activity of hexokinase recovered in the cell pellet was about 40 % higher in cross‐linked than control RINm5F cells. Although failing to affect the metabolism of L‐[U‐14C]glutamine, and severely decreasing the oxidation of D‐[U‐14C]glucose, the cross‐linking of proteins accentuated the increase in D‐[5‐3H]glucose utilization and D‐[U‐14C]glucose conversion to acidic metabolites resulting from a rise in hexose concentration from 2.8 to 16.7 mM. The latter change represents a mirror image of that previously found in cross‐linked pancreatic islets. Taking into account the vastly different participation of glucokinase to hexose phosphorylation in RINm5F cells and normal islet cells, the present findings further support, therefore, the regulatory role of protein‐to‐protein interaction in the control of glucokinase catalytic activity in these fuel‐sensing cells.
Functioning of oligomeric‐type light‐harvesting antenna
Authors: Timpmann K. E. , Taisova A. S. , Novoderezhkin V. I. , Fetisova Z. G. 
Published: July 2007

AbstractIn our previous work, we developed, for the first time, a theory of excitation energy transfer within an oligomeric‐type light‐harvesting antenna and, in particular, within the chlorosome of green bacteria (Biophys. J., 1996, vol.71, pp.995‐1010). The theory was recently developed for a new original exciton model of aggregation of chlorosomal pigments, bacteriochlorophylls (BChl) c/d/e (Biochem. Mol.Biol.Int., 1996, vol.40, No.2, pp. 243‐252). In this paper, it was demonstrated with picosecond fluorescence spectroscopy that this theory explains the antenna‐size‐dependent kinetics of fluorescence decay in chlorosomal antenna, measured for intact cells of different cultures of the green bacterium Chlorobium limicola with different chlorosomal antenna size determined by electron microscopic examination of the ultrathin sections of the cells. According to our model, the energy transfer dynamics within the chlorosome imply the formation of a cylindrical exciton, delocalized over a tubular aggregate of BChl c chains, and inductive‐resonance‐type transfer of such a cylindrical exciton between the nearest tubular BChl c aggregates and to BChl a of the chlorosome.
ATP/ADP antiporter‐ and aspartate/glutamate antiporter‐mediated fatty acid‐induced uncoupling of liver mitochondria in incubation media differing in ion composition
Authors: Samartsev Victor N. , Mokhova Elena N. 
Published: July 2007

AbstractSubstitution of potassium cloride for sucrose in the incubation medium of liver mitochondria or addition of magnesium cloride to the sucrose medium produces a small (if any) effect on the palmitate‐induced uncoupling and its sensitivity to carboxyatractylate and aspartate, but it exerts a pronounced increase in the recoupling effect of glutamate on this uncoupling. 20‐40 μM cetyltrimethyl ammonium bromide increases the recoupling effect of glutamate and aspartate but decreases that of carboxyatractylate. The data are in line with suggestion that both ATP/ADP antiporter and aspartate/glutamate antiporters are involved in the fatty acid‐induced uncoupling.
Evaluation of antisense inhibition in a B cell model
Authors: McCall M. N. , Kuchel M. G. , Basten A. 
Published: July 2007

AbstractAn in vitro model has been developed in an attempt to optimise antisense inhibition in B cells as a prelude to transgenic studies. The hypotheses tested were that i) the 3′‐untranslated region would be an appropriate target for antisense inhibition; 2) the immunoglobulin heavy chain intronic enhancer could be used to enhance antisense inhibition via increased production of antisense transcripts; and 3) the mouse metallothionein‐1 promoter would allow induction of antisense inhibition in B cells. Secreted IgM protein and mRNA were monitored following the stable transfection of a B cell line, HO‐2.2, with a series of plasmid constructs containing antisense or sense target sequence DNA under the control of either the mouse metallothionein‐1 promoter or homologous (ie same promoter as target sequence) immunoglobulin heavy chain promoter. The 3′‐untranslated region proved to be an appropriate target resulting in 70% inhibition of IgM secretion. Compared with untransfected and sense controls, significant decreases in IgM secretion (and RNA levels) were detected in clones transfected with antisense constructs utilising the mouse metaltothionein‐1 promoter and the immunoglobulin heavy chain intronic enhancer elements. These clones exhibited a further significant reduction in secreted IgM production upon zinc induction. Hybridisation studies demonstrated that decreased protein production was most likely attributable to reduction in RNA levels. In contrast, transfection with antisense constructs had no effect on membrane IgM protein levels which not only confirmed the specificity of antisense action but meant that the B cell remained sensitive to receptor ligation. We conclude that reasonable antisense inhibition of gene product expression can be achieved in B cells by targeting the 3′‐untranslated region and using both an inducible promoter (mouse metallothionein‐1) and the IgH enhancer to aid antisense RNA production.
Binding of the bovine caseinoglycopeptide to the platelet membrane glycoprotein GPIbα
Authors: Chabance Béatrice , Qian Zu‐Yuan , Migliore‐Samour Danièle , Jollès Pierre , Fiat Anne‐Marie 
Published: July 2007

AbstractThe bovine caseinoglycopeptide (residues 106‐169), the C‐terminal part of κ‐casein, inhibited the von Willebrand factor‐dependent platelet aggregation in a dose‐dependent manner. An affinity matrix made of the caseinoglycopeptide selectively bound the platelet membrane glycoprotein GPIbα which contains the von Willebrand factor binding site. The amino acid residues of GPIbα participating in the caseinoglycopeptide binding were located after residue Glu90.
Simple and reliable procedure for PCR amplification of genomic DNA from yeast cells using short sequencing primers
Authors: Haaning Jesper , Oxvig Claus , Overgaard Michael Toft , Sottrup‐Jensen Lars 
Published: July 2007

AbstractYeast is widely used in molecular biology. Heterologous expression of recombinant proteins in yeast involves screening of a large number of recombinants. We present an easy and reliable procedure for amplifying genomic DNA from freshly grown cells of the methylotrophic yeast Pichia pastoris by means of PCR without any prior DNA purification steps. This method involves a simple boiling step of whole yeast cells in the presence of detergent, and subsequent amplification of genomic DNA using short sequencing primers in a polymerase chain reaction assay with a decreasing annealing temperature.
Selective excitation of tryptophans in OmpF: A fluorescence emission study
Authors: Pattnaik Bikash Ranjan , Ghosh Subhendu , Rajeswari Moganty R. 
Published: July 2007

AbstractThe fluorescence studies of E. coli porin OmpF at pH 7.5 were carried out using excitation at 280 and 305 nm. Similar studies were performed in presence of a denaturant (urea) and a quencher (KI). Results show that both the tryptophans present in OmpF (residue numbers 61 and 214) contribute to fluorescence at 280 nm excitation, whereas only one residue shows fluorescence emission when excited at 305 nm. Based on these findings and the available crystal structure, it is speculated that tryptophan 61 of OmpF is selectively excited at 305 nm. The present studies point out some interesting features of the tryptophan microenvironments in OmpF.
Role of H‐ras gene in chronic liver damage in mice. By using transgenic mice carrying a human c‐H‐ras proto‐oncogene without mutations
Authors: Tsunematsu Satoshi , Saito Hidetsugu , Sato Reiko , Morizane Toshio , Ishii Hiromasa 
Published: July 2007

AbstractHepatic tumors including hepatocellular carcinoma were generated by carbon tetrachloride in transgenic mice carrying a human c‐H‐ras gene (rasH2 mice). RasH2 mice express 2 to 3 times more ras protein (ras p21) in the liver than do non‐Tg mice. When carbon tetrachloride was administered, the rasH2 mice produced about 5 times as many hepatic tumors than did the non‐transgenic mice. However, neither the 10‐100 times higher ras p21 expression required for murine fibroblast transformation by itself nor the mutational activation of the H‐ras gene was observed in carbon tetrachloride‐induced hepatic tumors. These results show that H‐ras proto‐oncogene expression in the murine liver, even if it is not high enough to transform cells, also causes liver tumors when CCl4 are repeatedly given.
Determination of sugar specificity of jackfruit lectin by a simple sugar‐lectin binding assay using microtiter plate
Authors: Wetprasit Nuanchawee , Chulavatnatol Montri 
Published: July 2007

AbstractSugar‐lectin binding assay was developed as a simple method which employed direct coating of microtiter plate with galactose‐binding lectins. Biotin‐galactose conjugate was used to bind to the immobilized lectins. The bound conjugate was then detected using streptavidin‐horseradish peroxidase. Using the assay in conjunction with various competing carbohydrates, jackfruit lectin from Artocarpus heterophyllus was found to be specific for α‐anomer of galactoside with an aromatic residue.