bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evidence for the shikimate‐3‐phosphate interacting site in the N‐terminal domain of 5‐enolpyruvyl shikimate‐3‐phosphate synthase of Bacillus subtilis
Authors: Selvapandiyan Angamuthu , Ahmad Suhail , Majumder Kumud , Arora Naresh , Bhatnagar Raj K. 
Published: July 2007

AbstractThe role of basic amino acid residues that are highly conserved in the N‐terminal domain of 5‐enolpyruvyl shikimate‐3‐phosphate synthase (EPSPs) in the binding of the substrate, shikimate‐3‐phosphate, has been assessed. Lys 19 and Arg 24 in the Bacillus subtilis EPSPs were substituted by glutamic acid and aspartic acid residues respectively by site‐directed mutagenesis. Native and the mutant proteins were expressed using a two‐vector system and the expressed proteins were purified to near homogeniety. The replacement of either Lys 19 or Arg 24 with a negatively charged residue nearly completely abolished the enzyme activity. The kinetic characterization of the purified wild type and the mutant proteins revealed that the substitution of positively charged residues in the N‐terminal domain (K19 and R24) results in reduced affinity for shikimate‐3‐phosphate (S3P). The results suggest the involvement of these residues in the binding of S3P during enzyme catalysis.
GM‐CSF induces the tyrosine phosphorylation of three isoforms of shc and its association with GRB2 in TF‐1 cell
Authors: Shi Xiaoqing , Qin Junchuan , Zhu Dexu 
Published: July 2007

AbstractThis report demonstrates that GM‐CSF induces the tyrosine phosphorylation of Shc protein which is implicated in Ras activation. Three isoforms of She are ubiqitously phosphorylated induced by GM‐CSF in TF‐1, a cell line of erythroid origin. It is also shown that She is associated with the adaptor protein Grb2. The formation of Shc‐Grb2 complex may directly link tyrosine phosphorylation events to Ras activation in TF‐1 cells.
Bovine papilomavirus oncoprotein E5 induces the NFκB activation through superoxide radicals
Authors: Kilk Ann , Talpsepp Tiit , Väli Ülo , Ustav Mart 
Published: July 2007

AbstractBovine papillomavirus type 1 (BPV‐1) open reading frame E5 encodes the smallest known oncoprotein. This protein is involved in transforming cells during the early stage of infection. Nuclear factor κB (NFκB) is activated in the host cells as a result of different virus infections. It has been shown that reactive oxygen intermediates activate NFκB which leads to the activation of several cellular genes. We studied the effect of BPV‐1 E5 protein on NFκB activation. We found that low and moderate concentrations of E5 protein activate NFκB. This activation is suppressed by superoxide dismutase. We conclude that the superoxide anion is involved in activation of NFκB.
Ginsenoside‐Rh1 and Rh2 inhibit the induction of nitric oxide synthesis in murine peritoneal macrophages
Authors: Park Young Chul , Lee Chang Hoon , Kang Ho Sung , Kim Kyu‐Won , Chung Hun Taeg , Kim Han Do 
Published: July 2007

AbstractThe effects of ginsenoside‐Rh1 and Rh2 in the induction of nitric oxide (NO) synthesis by IFN‐γ plus LPS were investigated using murine peritoneal macrophages. The NO production from rIFNγ plus LPS‐treated macrophages was markedly reduced by ginsenoside‐Rh1 or Rh2 in a dose dependent manner, but had no inhibitory effects by ginsenoside‐Rb1, Rc or Re. In addition, treatment of the cells with ginsenoside‐Rh2 6 hr before the stimulation with IFN‐γ plus LPS showed more inhibitory effect than the treatment with ginsenoside‐Rh2 6 hr after or simultaneously with the stimulation with IFN‐γ plus LPS in the NO production. Ginsenoside‐Rh2 also effectively inhibited IFN‐γ‐induced NO production when the cells were treated with IFN‐γ 6 hr after the treatment with ginsenoside‐Rh2. Our findings suggest that this phenomenon might be caused by inhibition of priming signal such as IFN‐γ for the synergistic induction of NO synthesis.
Normalization of immune response and phosphoinositide fatty acid composition of peripheral blood lymphocytes in an alcoholic patient after alcohol abstinence
Authors: Stefanini G. F. , Castelli E. , Foschi F. G. , Marsigli L. , Addolorato G. , Celadon M. , Biagi P. L. , Bordoni A. , Gasbarrini G. , Hrelia S. 
Published: July 2007

AbstractAfter 10 months of alcohol abstinence a malnourished alcoholic patient improved his nutritional status. The analysis of peripheral blood lymphocyte response to mitogenic stimulation with the antibody anti‐CD3 and of the fatty acid composition of the (poly)‐phosphoinositide fraction derived from lymphocytes revealed: 1) a similar [3H]‐thymidine uptake as in control (non‐drinker) subjects; 2) a similar relative molar content of the main fatty acids in the (poly)‐phosphoinositides as in control subjects. Alcohol abstinence can normalize both the parameters, which are greatly altered during alcohol abuse. This suggests a link between nutritional status and lymphocyte responsiveness via phosphoinositide fatty acid composition.
Affinity purification of mannose 6‐phosphate receptor proteins. Purification and partial characterisation of goat liver receptors
Authors: Yerramalla Udaya Lakshmi , Nadimpalli Siva Kumar 
Published: July 2007

AbstractMannose 6‐phosphate receptor (MPR) proteins designated as MPR 300 and MPR 46 have earlier been purified from some mammals on phosphomannan coupled to cyanogen bromide activated Sepharose. In a recent study, the goat liver MPR 300 has been directly purified using Sepharose‐divinylsulfone‐pentamannosyl phosphate matrix (Sivakumar N. 1996, J.Biochem. Biophys. methods, 31, 181‐184(1)). In the present report, we describe the preparation of another affinity matrix Sepharose‐divinylsulfone‐phosphomannan and its utility in purifying the MPR proteins from goat liver. While the MPR 300 from goat liver showed an electrophoretic mobility similar to other mammalian MPRs, the small receptor showed a molecular weight of 36 kDa. Antibodies raised against goat liver MPR 300 react specifically with the large receptor protein. Additionally affinity purified peptide specific antibody corresponding to amino‐acid residues 26‐42 (ADGCDFVCRSKPRNVPA) of the cytoplasmic tail of the human liver MPR 46 (Pohlmann et al, 1988. Proc. Natl. Acad. Sci. USA, 84, 5575‐5579 (2)) cross‐reacts with the purified small receptor.
Catalytic roles of lysines (K9, K27, K31) in the N‐terminal domain in human adenylate kinase by random site‐directed mutagenesis
Authors: Ayabe Takanori , Park Seung Kyu , Takenaka Hitoshi , Sumida Michihiro , Uesugi Seiichi , Takenaka Osamu , Hamada Minoru 
Published: July 2007

AbstractTo elucidate lysine residues in the N‐terminal domain of human cytosolic adenylate kinase (hAK1, EC 2.7.4.3), random site‐directed mutagenesis of K9, K27, and K31 residues was performed, and six mutants were analyzed by steady‐state kinetics. K9 residue may play an important role in catalysis by interacting with AMP2‐. K27 and K31 residues appear to play a functional role in catalysis by interacting with MgATP2‐. In human AK, the ε‐amino group in the side chain of these lysine residues would be essential for phosphoryl transfer between MgATP2‐ and AMP2‐ during transition state.
Cloning, expression and characterization of a blood group B active recombinant α‐D‐galactosidase from soybean (Glycine max)
Authors: Davis Melissa O. , Hata D. Jane , Johnson Scott A. , Walker John C. , Smith Daniel S. 
Published: July 2007

AbstractA cDNA encoding soybean α‐D‐galactosidase [E.C. 3.2.1.22] was obtained by screening a soybean library with Phaseolus α‐D‐galactosidase cDNA. The Glycine max α‐D‐galactosidase cDNA is 1.75 kb long and contains untranslated 5′ and 3′ sequences. The deduced amino acid sequence of the soybean gene has a high degree of homology with other eucaryotic α‐D‐galactosidases. Recombinant α‐D‐galactosidase (rGal) was expressed in Pichia pastoris and purified by affinity chromatography. Purified rGal was homogeneous as judged by SDS‐PAGE analysis with the relative molecular mass under reducing conditions of 39.8, and under nonreducing conditions 38.0 kDa. The expressed protein contained the sequence NGLGHTPPMG at the N‐terminus, corresponding to the deduced amino acid sequence of the soybean gene. The relative native molecular mass by Sephacryl S‐200 chromatography was determined to be 33.1 kDa. The specific activity was 295.6 μmoles of PNP‐α‐D‐galactopyranoside hydrolyzed per mg pure rGal per min. rGal was highly specific for α‐D‐galactosyl residues. No detectable hemagglutinin or protease activity was present in the preparations. Furthermore, rGal was active against the blood group B antigen in native human erythrocyte cell suspension assays. The only detectable erythrocyte phenotypic change was loss of the B and P1 epitopes. Consequently, recombinant Glycine max α‐D‐galactosidase may have useful biotechnical applications in the potential mass production of universally transfusable type O erythrocytes by enzymatic conversion.
β1 integrin subunit dimerization via disulfide bonds
Authors: Belkin Vladimir M. , Kozlova Nadezhda I. , Bychkova Victoria V. , Shekhonin Boris V. 
Published: July 2007

AbstractIntegrins of the β1 family were isolated from human smooth muscle. SDS‐PAGE analysis and subsequent immunoblotting demonstrated that integrin samples contain a protein immunologically related to β1 integrin subunit with the previously undescribed apparent molecular mass 205 kD. One‐dimensional peptide mapping showed that the 205 kD protein is not a novel β1 related integrin subunit, but a β1 integrin subunit dimer. After reduction the major part of the β1 immunoreactive material migrated from the 205 kD to 130 kD region, indicating that β1 integrin subunit dimers were formed via disulfide bonds. When electrophoretically pure β1 monomer and dimer forms were analized it was found that during SDS‐PAGE about 30% of β1 integrin subunit monomers were organized into dimers while approximately 70% of the β1 dimer form was partly disrupted into monomers. It was suggested that this steady‐state process is a result of a reversible reaction between intra‐ and intermolecular disulfide bonds. Possible in vivo dimerization of integrins via disulfide bonds is discussed.
Characterization of natriuretic peptide receptors in the rat parotid
Authors: Nashida Tomoko , Imai Akane , Shimomura Hiromi 
Published: July 2007

AbstractCompetition studies between 125I‐ANP and ANP (atrial natriuretic peptide) or the ring‐deleted analog C‐ANF4‐23 (C‐ANF) revealed the presence of the A‐type natriuretic peptide receptor (GC‐A receptor) and the ANP‐clearance (ANP‐C) receptor in the rat parotid membrane. The ratio of the GC‐A and ANP‐C receptors was about 3 to 1. Enhancement of the cGMP level by the C‐type natriuretic peptide (CNP) revealed the presence of the B‐type natriuretic peptide receptor (GC‐B receptor) in the rat parotid gland. Based on the binding studies with ANP and C‐ANF and cGMP analysis by ANP and CNP, the natriuretic peptide receptors in the rat parotid gland were demonstrated to have a rank order on the amount of GC‐A receptor > GC‐B receptor > ANP‐C receptor.
Proton pump and auxin effect in Arabidopsis thaliana leaves during the development
Authors: Bellamine Jalil , Greppin Hubert 
Published: July 2007

AbstractThe plasma membrane from Arabidopsis thaliana leaves (wild‐type and F mutant) has been purified by two‐phase partitioning and the H+‐transport activity was tested in vitro in the presence of different concentrations of IAA. While 1 µM of IAA had no effect, higher concentrations (10 µM and 100 µM) were inhibitory in 25 short days grown wild‐type plants. However, the activity was increased by about 16 % after 10 supplementary short days of growth (from 25 to 35 SD) in the represence of 10 µM of IAA. No significant sensitivity to the tested concentrations of auxin was observed during the development in short days (30, 38, 42 SD) or even the plants were induced by a 24 h of continuous light. The variability was not observed for a given developmental stage, from one experiment to another, but it was also observed after light induction of F mutant plants.
Kinetics of inhibition of green crab (Scylla serrata) alkaline phosphatase by phenylglyoxal
Authors: Xie Wen‐Zhang , Wang Hong‐Rui , Chen Qing‐Xi , Zhou Hai‐Meng 
Published: July 2007

AbstractThe kinetics method of the substrate reaction during modification of enzyme activity previously described by Tsou (Adv. Enzymol. Related. Areas Mol. Biol., 1988, 61, 381‐436) has been applied to study the kinetics of the course of inactivation of green crab alkaline phosphatase by phenylglyoxal. The obtained results shows that the inactivation of the enzyme by phenylglyoxal is a slow reversible reaction. The microscopic rate constants for the reaction of the inhibitor with the enzyme were determined. The presence of substrate offers marked protection of this enzyme against inactivation by phenylglyoxal. The above results suggest that the arginine residue is essential for activity and is situated at the active site of the enzyme.
A novel DNA cleaving agent, 2,2′‐bis(2‐aminoethyl)‐4,4′‐bithiazole, induces thymocyte apoptosis
Authors: Lee Eibai , Miyaguchi Fumiko , Inoue Maho , Kariya Kimio , Sasaki Hideaki 
Published: July 2007

AbstractThe incubation of rat immature thymocytes with 2,2‐bis(2‐aminoethyl)‐4,4′‐bithiazole, which possesses the cleaving activity toward plasmid DNA in the presence of Co2+, resulted in an increase in DNA fragmentation. No DNA fragmentation of the cells was induced by 2,2‐bis(3‐aminopropyl)‐4,4′‐bithiazole, which has little cleaving activity toward plasmid DNA. Analysis of fragmented DNA from thymocytes treated with 2,2‐bis(2‐aminoethyl)‐4,4′‐bithiazole by agarose gel electrophoresis revealed that the compound produced 50 kbp DNA fragments and caused internucleosomal DNA fragmentation. In addition, the confocal microscopic images of thymocytes treated with the compound showed condensation of chromatin. These results indicate that bithiazole derivative induces thymocyte apoptosis with the biochemical and morphological characteristics through triggerring DNA scission.
Does an increase in dietary linoleic acid modify tissue concentrations of cervonic acid and consequently alter alpha‐linolenic requirements? Minimal requirement of linoleic acid in adult rats
Authors: Bourre J‐M. , Dumont O. , Durand G. 
Published: July 2007

AbstractRats were fed a control diet containing both linoleic and alpha‐linolenic acid. When 60‐days‐old they were divided into 8 groups, each receiving the same amount of alpha‐linolenic acid, but varying amounts of linoleic acid. When the (n‐6)/(n‐3) ratio in the diet varied from 2 to 32 (with a constant amount of 150 mg alpha‐linolenic acid per 100 g diet), tissue levels of the (n‐3) series fatty acids were not significantly modified, except in the liver, heart and testes. In all organs studied, the saturated and monounsaturated fatty acids were practically unchanged. For the (n‐6) series fatty acids, arachidonic acid was not significantly affected, in muscle, kidney, brain, myelin, nerve‐endings or sciatic nerve, whatever the quantity of linoleic acid in the diet. In liver, arachidonic acid plateaued at 2400 mg linoleic acid/ 100 g diet and at 400 mg /100g diet in heart. Results for 22:5(n‐6) showed a marked increase in heart, a moderate increase in liver and kidney, and no effect in muscle, testes, brain, myelin, nerve‐endings or sciatic nerve. This experiment defined the minimum amount of linoleic acid required in the diet to maintain fatty acids of the linoleic family in the young adult rat. For the first time it was demonstrated that 1200 mg/100 g diet are sufficient for the liver, as evidenced by maintenance of the arachidonic acid concentration. For the other organs, there is either a very marked preservation of this acid, or the dietary level is less than 300 mg/100 g diet. For the essential fatty acid precursors (i.e. linoleic and alpha‐linolenic acids), the optimal (n‐6)/(n‐3) ratio required in the diet is about 8.
tRNATrp as cofactor of gelonin, a ribosome‐inactivating protein with RNA‐N‐glycosidase activity features required for the cofactor activity
Authors: Brigotti Maurizio , Carnicelli Domenica , Alvergna Paola , Pallanca Alessandra , Sperti Simonetta , Montanaro Lucio 
Published: July 2007

AbstractPurified beef and rabbit liver tRNATrp, but not yeast tRNATrp, increase the in vitro inactivation of eukaryotic ribosomes by gelonin, a ribosome‐inactivating protein with RNA‐N‐glycosidase activity on 28S rRNA. Aminoacylation and stepwise trimming of the 3′‐end of bovine tRNATrp affect the cofactor activity, the most active species being that shortened by the last two nucleotides. ATP only moderately increases the activity of purified mammalian tRNATrp and in this increase the cognate aminoacyl‐tRNA synthetase apparently has no role. Mobility shift experiments indicate that bovine tRNATrp binds both to ribosomes and to gelonin and favours the dissociation of gelonin from ribosomes.
Epitope mapping of preS2 of the hepatitis B virus surface antigen against a conformation‐dependent monoclonal antibody using synthetic peptides
Authors: Lee Myung Kyu , Kim Kil Lyong , Hahm Kyung‐Soo 
Published: July 2007

AbstractPreviously we reported that the N‐terminal sequence 120/123‐129 of the preS2 region of the hepatitis B virus surface antigen plays an important role on peptide antigenicity against a monoclonal antibody H8 (H8 mAb) by affecting the B cell epitope conformation of a peptide existing within the sequence 130‐145 (Lee et al., Biochem. Mol. Biol. Int., 34, 159‐168, 1994). In this study, we try to map the H8 mAb binding site using a series of substituted peptides in the sequence 131‐143 by competitive ELISA. Peptide antigenicities were greatly reduced when the residues 131 (L), 137 (R), 140 (Y), 141 (F) and 142 (P) were substituted. The residues 133 (D), 134 (P) and 136 (V) had a slight affect on the mAb binding, whereas the residues 135 (R) and 139 (L) had no effects on the mAb binding. In contrast to H8 mAb, however, three anti‐HBsAg polyclonal antisera showed the lowest bindings to the peptide substituted at position 135. These results suggest that the epitope against H8 mAb is discontinuously conformational.
Modulation of ouabain sensitive sodium potassium pump of erythrocytes from patients with chronic renal failure:Role of acute hemodialysis
Authors: Prasad R. , Mond R. , Jain S. , Kaur G. , Chugh K. S. 
Published: July 2007

AbstractSignificantly higher levels of plasma urea creatinine and potassium were observed in patients with renal failure compared to normal controls. The RBC sodium concentration was raised whereas the RBC potassium concentration was decreased in chronic renal failure. These alterations in the RBC Na1 and K1 concentrations were associated with decrease in ouabain sensitive sodium efflux rate and ouabain sensitive sodium efflux rate constant. However, there was no significant impact of acute hemodialysis on the intracellular electrolytes levels, ouabain sensitive sodium efflux rate and ouabain sensitive sodium efflux rate constant. These findings suggest an intrinsic alteration in the transport capacity of Na+‐K+ pump which could account for the rise in intracellular sodium and fall in intracellular potassium content in the RBCs of chronic renal failure patients.
The effects of decyl aurachins C and D on the respiratory electron flow of facultative phototrophic bacteria
Authors: Romagnoli Simona , Oettmeier Walter , Zannoni Davide 
Published: July 2007

AbstractDecyl aurachins C and D are two synthetic compounds related to the natural products aurachins C and D extracted from Stigmatella aurantiaca. Titrations of a range of partial respiratory activities in membranes from facultative phototrophs indicate that decyl aurachin C is more effective than aurachin D in inhibiting the quinol oxidase. Decyl aurachin C also affects the NADH‐ubiquinone oxidoreductase of Rhodobacter capsulatus and the cytochrome bc1 complexes of Rb. capsulatus and Rhodospirillum centenum. Titration of the light‐induced respiration in Rsp. centenum allowed us to estimate an upper limit for the ubiquinol oxidase concentration of 1.5±0.2 nmol/mg protein, or a ubiquinol oxidase/cytochrome c oxidase ratio of 3:1.
Antioxidant property of Fructus Momordicae extract
Authors: Shi Honglian , Hiramatsu Midori , Komatsu Makiko , Kayama Takamasa 
Published: July 2007

AbstractThe antioxidant effect of Fructus Momordicae extract, FME (mogrosides 75‐80%), was studied. FME reduced the stable free radical 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) and scavenged superoxide radicals (O2‐) generated by a hypoxanthine and xanthine oxidase system. It also scavenged hydroxyl radicals (⊎OH) generated by Fenton reaction. In addition, FME inhibited Fe(II) induced lipid peroxidation in rat cortex homogenates in a dose‐dependent manner, as indicated by decreased thiobarbituric acid‐reactive substances (TBARS) formation. Oral administration of FME inhibited TBARS and malonaldehyde (MDA) formation in the ipsilateral cortex 30 min after iron‐salt injection into the left cortex of rat. FME showed inhibitory effect on 4‐hydroxy‐2(E)‐nonenal (4‐HNE) formation induced by Fe(III) injection into the rat cortex. These data suggest that Fructus Momordicae extract has an antioxidant activity against free radicals and lipid peroxidation.
Chlorpromazine transport in membrane vesicles from multidrug resistant CCRF‐CEM cells
Authors: Syed Samiuddin K. , Christopherson Richard I. , Roufogalis Basil D. 
Published: July 2007

AbstractThe mechanism by which chlorpromazine (2‐chloro‐10‐(3‐dimethylaminopropyl)‐phenothiazine) reverses P‐glycoprotein (P‐gp2)mediated multidrug resistance was investigated using membrane vesicles prepared from human CCRF‐CEM leukaemia cells. Chlorpromazine was transported in an ATP‐dependent manner into membrane vesicles prepared from vinblastine resistant (VBL1000) cells but not from drug‐sensitive cells. The chlorpromazine uptake was sensitive to osmotic pressure, indicating true transport into the vesicle lumen. The ATP‐dependent chlorpromazine uptake was inhibited about 30% by the addition of ammonium chloride, indicating that a pH or electrochemical gradient could not account for the majority of ATP‐dependent chlorpromazine uptake. The results of this study show that chlorpromazine is actively transported by P‐glycoprotein and that chemosensitization by phenothiazines may occur by competition of these agents for active transport of anticancer agents by P‐glycoprotein.
Changes in fatty acid composition in rat adipose tissue induced by dietary obesity
Authors: Lladó Isabel , Pons Antoni , Palou Andreu 
Published: July 2007

AbstractThe aim of the study was to evaluate the effects of cafeteria feeding on the composition of fatty acids in retroperitoneal fat pad and also to determine what happens to fatty acids when rats previously fed the cafeteria diet are returned to regular rat chow. The study of the post‐cafeteria rats enabled us to determine the effects of dietary induced excess weight in the absence of artefactual interferences from the diet because these rats, unlike the cafeteria obese rats, ate the same diet as controls.In response to cafeteria feeding there were increases in the majority of adipose tissue fatty acids. However, significant decreases were observed in the relative proportions of 18:2n‐6 and in two related n‐6 polyunsaturated fatty acids (18:3n‐6 and 20:3n‐6), as well as in 16:1. In the post‐cafeteria obesity model the previous dietary influence on fatty acid composition was still evident. The maintenance of both the high levels and proportions of 18:1 and the decrease of 16:1 percentage in the post‐cafeteria rats argues in favour of an alteration in the activity of the elongation metabolic pathway. Certain changes affecting polyunsaturated fatty acid adipose depot composition of obese rats, mainly the decreased levels of 18:2n‐6, are long lasting and could be related to the maintenance of the obese status. On the whole, although the fatty acid composition of adipose tissue is influenced by the composition of the diet, there are some differences in both the maintenance of the effects and also in the selectivity of adipose tissue for the different fatty acids of obese and lean rats.