bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modification of human neuron‐specific enolase for application to radioimmunoassay
Authors: Aoki Takashi , Kaneta Mitsuhiro , Onagi Hitoshi , Morikawa Junji , Tsubota Nobuyuki , Watabe Hiroyuki 
Published: July 2007

AbstractA recombinant human neuron‐specific enolase (R‐NSE), isolated from Escherichia coli, could not be used in an RIA system because of instability upon labeling. To apply R‐NSE to RIA and to simplify the purification procedure, the N‐ and C‐terminals of R‐NSE were modified by tyrosine‐ and histidine‐tagging, respectively. SY‐NSE, containing one additional tyrosine residue, was obtained from both soluble and insoluble fractions. More derivatives tagged by two or four tyrosine residues were expressed, but only in the insoluble fraction. SY‐NSE and SY‐NSE.H6 (containing six histidine residues at C‐terminal of SY‐NSE) purified from the soluble fraction were applicable to the RIA system, indicating that the addition of a tyrosine residue at the terminal is effective if the antigen is unstable during labeling.
Design of an artificial hemoprotein based on human serum albumin
Authors: Shumyantseva Victoria V. , Bulko Tatyana V. , Zimin Alexander G. , Uvarov Valentine Yu. , Archakov Alexander I. 
Published: July 2007

AbstractFor modelling cytochrome P450‐catalyzed reactions, an artificial hemoprotein was designed. Upon complex formation of human serum albumin with iron protoporphyrine IX, there occurred the incorporation of heme into the protein and formation of a specific complex with the albumin to heme molar ratio 2:1. The apparent dissociation constant Kd of the complex, as determined by optical absorption spectroscopic technique, was 1.9±0.4 M‐6. Based on spectral studies and molecular modelling of the complex spatial structure, it was assumed that His 31 or His 90 may be the most probable 5th ligand for the heme iron. The artificial hemoprotein was able to catalyze (in the presence of riboflavin as electron carrier) the NADH‐dependent aniline hydroxylation and dimethylaniline and amidopyrine N‐demethylation. The electron transfer pathway from NADH to substrate was demonstrated. Flavin appears to serve as an input center (mediator) for the rapid transfer of electrons from NADH to heme, where substrate is oxidized. The same reactions were accomplished using riboflavin photoreduction in the hemoalbumin ‐ riboflavin system with the unfocussed laser emission at λ=457.9 nm. As electron donor, metallic zinc was used. The artificial hemoprotein obtained was also able to catalyze H2O2‐dependent oxidase reactions.
Purification and characterization of chromogranin‐A from the adrenal gland of human and bovine
Authors: Kumar Ujendra 
Published: July 2007

AbstractIn the present study, we report a simple, highly reproducible procedure for the purification of chromogranin A. A three step column chromatography of supernatant from human and bovine provided a major single band at Mr 67 and two minor bands at low molecular mass. Identity of the major and minor bands of CgA was confirmed by western blotting using LK2H10, a monoclonal antibody against chromogranin A. Recognition of smaller fragments in the final preparation in both species by antibody to chromogranin A may suggest that these are the proteolytic breakdown product of the main protein. Bovine adrenal gland was found to be many fold richer in chromogranin than human adrenal gland. The simplification of the purification procedure for CgA may now help in elucidating further physiological function of this protein.
Activation of the intracellular Ca2 ‐dependent serine protease ISP1 of Bacillus megaterium by purification of by high Ca2 concentrations
Authors: Váchová Libuše 
Published: July 2007

AbstractThe total proteolytic activity of ISP1 determined after its partial purification by size exclusion HPLC increased 3.0, 7.3 and 27.3 times in sporulating, growing and netropsin‐treated cells, respectively, as compared with the corresponding original activity in crude cytoplasmic preparations at the same CaCl2 concentration of 3 mM. A similar rise in proteolytic activity occurred on increasing the Ca2+ concentration in the crude cytoplasm from 3 to 30 mM. This activation in the cytoplasm of netropsin‐treated and sporulating cells was not reversed by subsequent lowering of CaCl2 concentration back to 3 mM by dialysis. Moreover, a similar activation appeared even after the same dialysis of cytoplasm that had not been exposed to 30 mM CaCl2. The activation was probably due to the processing of ISP1, as established by SDS‐PAGE and immunoblotting, but an involvement of additional regulation factor(s), e.g. an inhibitor or other molecules, is possible.
Redox regulation of signal transduction in smooth muscle cells: Protein kinase C inhibition by thiol agents
Authors: Taher Mohiuddin M. , Abd‐Elfattah Anwar S. A. 
Published: July 2007

AbstractThiol depleting agents phenylarsine oxide and N‐ethylmaleimide significantly inhibited the phorbol ester induced protein kinase C activation in vascular smooth muscle cells. Phenylarsine oxide is a good protein tyrosine phosphatase inhibitor. Sodium orthovanadate, also a protein tyrosine phosphatase inhibitor, neither activated nor inhibited protein kinase C in vascular smooth muscle cells. Phenylarsine oxide, N‐ethylmaleimide, orthovanadate, hydrogen peroxide and pervanadate [sodium orthovanadate + hydrogen peroxide] all significantly induced mitogen activated protein kinase in vascular smooth muscle cells. Phorbol ester and platelet derived growth factor induced mitogen activated protein kinase was inhibited by phenylarsine oxide pretreatment to vascular smooth muscle cells. However, hydrogen peroxide/pervanadate induced mitogen activated protein kinase was not prevented by phenylarsine oxide. These results suggest that oxidation of the cellular thiols inhibits the protein kinase C and activates mitogen activated protein kinase in vascular smooth muscle cells. In addition, peroxides induced, the activation of mitogen activated protein kinase in vascular smooth muscle cells which is independent of protein kinase C.
Susceptibility of growth factors to degradation by Helicobacter pylori protease: Effect of ebrotidine and sucralfate
Authors: Slomiany B. L. , Piotrowski J. , Slomiany A. 
Published: July 2007

AbstractIn this study, we investigated the susceptibility of the growth factors (EGF, bFGF, TGFß and PDGF) to degradation by the protease elaborated by H. pylori and assessed the effect of antiulcer agents, ebrotidine and sucralfate, on this enzymatic action of the bacterium. The colonies of H. pylori were washed with saline, filtered to retain the bacteria, and the filtrate used as an enzyme source. The assays revealed that while EGF and ßFGF showed only marginal (5‐7%) susceptibility to H. pylori protease, a 61.7% degradation occurred with PDGF and 62.3% with TGFß. Introduction of ebrotidine or sucralfate to the assay system led to the reduction in the rate of growth factors degradation, which at 50µg/ml ebrotidine reached the value of 85.1% for PDGF and 88.6% for TGFß, while with sucralfate the optimal inhibition of PDGF (79.6%) and TGFß (82.7%) degradation occurred at 200µg/ml. The results demonstrate that PDGF and TGFß are susceptible to H. pylori degradation and that antiulcer agents, ebrotidine and sucralfate are capable of counteracting this effect.
Interaction of polyadenylic acid (5′) with histone H1 or protamine
Authors: Kuo Wu‐Nan , Chambers Maxine C. , Jn‐Baptiste Junior B. 
Published: July 2007

AbstractThe interaction between polyadenylic acid (5′) (poly[A]) and histone (or protamine) was analyzed by electrophoretic retardation of poly[A]‐histone (or protamine) complex in agarose gel. The potency of interaction was protamine > histone H1, arginine‐rich histone > other histones. The catalytic subunit of cyclic AMP‐dependent protein kinase effectively decreased the electrophoretic retardation of poly[A]‐histone H1. The interaction between poly[A] and histone H1 was also detected by the drastically enhanced absorbance around 340 nm. The findings may implicate a regulatory role of histone H1 on mRNAs through its binding on poly[A] tails.
Alterations in circulating fatty acids and the compartmentation of selected metabolites in women with breast cancer
Authors: Quevedo‐Coli S. , Crespi C. , Benito E. , Palou A. , Roca P. 
Published: July 2007

AbstractThe presence of the tumor in women with breast cancer provokes a profile of biochemical change characterized by hypoglycemia, hypemremia and high levels of free fatty acids and ketone bodies in plasma. The total circulating levels of amino acids and lactate are slightly higher in patients with breast cancer. Moreover, alterations in the circulating levels of free and total fatty acids are associated with enhanced levels of total free fatty acids and significantly lower levels of esterified arachidonic acid. This profile may indicate a state of moderate catabolic activation in breast cancer patients and may also be associated with a slight mobilization of proteins and fatty acids by some of the peripheral tissues in order to cover the needs of the host and the tumor. However, the alteration in the distribution of different fatty acids (saturated, mono‐unsaturated and poly‐unsaturated) and the different behaviour of the free and esterified fractions may be the result of a greater release of only specific fatty acids by tumor or other host tissues, rather than a higher release of the whole spectrum of free fatty acids. Thus, it is proposed that some of the alterations may be directly related to localized tumor activity.
Spectroscopic characterization of the uptake of essential and xenobiotic metal cations in cells of the soil bacterium Azospirillum brasilense
Authors: Kamnev A. A. , Renou‐Gonnord M. ‐F. , Antonyuk L. P. , Colina M. , Chernyshev A. V. , Frolov I. , Ignatov V. V. 
Published: July 2007

AbstractThe results of flame (FAAS) or graphite furnace atomic absorption spectrometric (GFAAS) analyses are presented and discussed on the accumulation of essential metals (Mg, Ca, Mn and Fe contained in the cultivation medium) and traces of each one of the conventionally xenobiotic elements from the group V, Co, Ni, Cu, Zn or Pb, added to the medium in concentrations (0.2 mM) which do not essentially suppress growth of the bacterial culture, in cells of the plant root‐associated nitrogen‐fixing bacterium Azospirillum brasilense. Along with the essential cations assimilated by the bacterium, Zn and Cu were found to effectively accumulate in the biomass from the environment. The uptake of Co and Ni was significantly less pronounced, whereas Pb and V appeared to be present in cells in much lower concentrations than in the cultivation medium evidently showing no tendency to be assimilated by azospirilla. The effect of the above xenobiotics on the uptake level of the four essential elements provided evidence that they may compete for the formation of biologically active complexes with substances of both intracellular and extracellular localization. The analytical data obtained are compared with Fourier transform infrared (FTIR) spectra of intact vacuum‐dried bacterial cells grown in a standard medium and under the conditions of an increased metal uptake.
Isolation and characterization of an enzyme from sheep seminal vesicles that catalyzes the glutathione‐dependent prostaglandin H2 to prostaglandin F2α
Authors: Burgess John R. , Reddy C. Channa 
Published: July 2007

AbstractAn enzyme which catalyzes the direct 2‐electron reduction of prostaglandin H2 to prostaglandin F2α has been purified from the microsomes of sheep seminal vesicles. This enzyme, called prostaglandin endoperoxide reductase, was found to be a monomer of 16,500 molecular mass. The activity of the enzyme was dependent on reduced glutathione, enhanced by heat‐treatment, and inhibited by sulfhydryl reagents. The enzyme is not a glutathione S‐transferase nor does it utilize prostaglandin D2 as a substrate, and thus is distinct from previously characterized prostaglandin F2α, biosynthetic enzymes. The protein also catalyzes the reduction of cumene hydroperoxide, but not hydrogen peroxide. Thus, this microsomal prostaglandin endoperoxide reductase may play an important role in the synthesis of prostaglandin F2α, in some tissues.
Salt‐induced folding of alkaline denatured creatine kinase under high pH conditions
Authors: Yang Hai‐Peng , Zhong Hai‐Ning , Li Sen , Zhou Hai‐Meng 
Published: July 2007

AbstractThe conformational changes of creatine kinase during alkaline unfolding and salt‐induced folding at high pH have been followed by fluorescence emission and circular dichroism spectra. The results obtained show that at low ionic strength, with increasing pH value, creatine kinase denatured gradually to reach the ultimate unfolded conformation in the vicinity of pH 12.7. With the increase of pH from 9.0 to 12.7, the fluorescence emission maximum red shifted from 337 to 355 nm, indicating complete exposure of the buried tryptophan residues to the solvent. The far‐UV CD spectra show that even at pH 12.7, the apparently fully denatured enzyme retains a great part of ordered secondary structure. At pH 12.7 by adding the salt, the relatively unfolded state of denatured enzyme changes into a compact conformational state by hydrophobic collapsing. Folded state induced by salt bound ANS strongly, indicating the existence of increased hydrophobic surface. The above results suggest that the salt‐induced folded state at high pH may be the folded intermediate which exists in the general protein folding, and the larger residual ordered secondary structure might become folded being point on the salt‐induced folding.
Aloesin up‐regulates cyclin E/CDK2 kinase activity via inducing the protein levels of cyclin E, CDK2, and CDC25A in SK‐HEP‐1 cells
Authors: Lee Kwang Youl , Park Jeong Hill , Chung Myung Hee , Park Young In , Kim Kyu Won , Lee Young Joo , Lee Seung Ki 
Published: July 2007

AbstractIn the present study, we show that aloesin, which is a low molecular weight ingredients present in Aloe vera, stimulates the proliferation of cultured human hepatoma SK‐HEP‐1 cells. The incorporation of [3H] thymidine into DNA in the cell cultures was significantly increased at a dose of 10 μM aloesin. The aloesin‐induced DNA synthesis appears to require newly synthesized proteins because cycloheximide treatment blocked the DNA synthesis evoked by this compound. We then examined whether this compound increases the intracellular levels of cell cycle regulators by immunoblotting. The data showed that aloesin increased the levels of cyclin E, CDK2, and CDC25A in SK‐HEP‐1 cells. In addition, immuno‐complex kinase assays showed that aloesin up‐regulated the enzyme activity of cyclin E/CDK2 kinase in a dose‐dependent manner. Collectively, these results suggest that aloesin stimulates the proliferation of SK‐HEP‐1 cells by inducing the intracellular levels of cyclin E/CDK2 kinase complex and CDC25A, which, together, result in the up‐regulation of cyclin E‐dependent kinase activity.
The antioxidant properties of thioctic acid: Characterization by cyclic voltammetry
Authors: Chevion S. , Hofmann M. , Ziegler R. , Chevion M. , Nawroth P. P. 
Published: July 2007

AbstractThioctic acid (TA) level and its antioxidant capacity were monitored by cyclic voltammetry (CV), in solution and in human plasma. A linear correlation between the anodic wave current Ia at 900 mV and [TA] was obtained. This indicates that TA, commonly found in human plasma, is an antioxidant component characterized by a potential E1/2=900 mV and constitute, at least in part, the second anodic wave of the CV tracing. When plasma from diabetic patients was analyzed by CV, those patients under treatment with TA showed higher Ia than others not taking the drug. When the patients under treatment with TA were divided into groups according to the severity of their nephropathy, or according to the severity of their total complication count, Ia levels representing TA were significantly higher in those patients with more severe complications.
Ca2 /calmodulin‐binding proteins in yeast. Catabolite repression and induction by carbon sources
Authors: Santos Carlos F. Tourinho dos , Larson Roy E. , Panek Anita D. , Paschoalin Vânia M. F. 
Published: July 2007

AbstractSoluble calmodulin‐binding proteins from Saccharomyces carlsbergensis were analyzed in cells grown on glucose, maltose and galactose as carbon source. A large number of polypeptide chains showed affinity for calmodulin by affinity chromatography and overlay techniques. Amongst these, polypeptides of 115, 67 and 45 kDa were only detected during the second exponential phase of growth on glucose or non‐fermentative carbon sources, suggesting that they might be subjected to catabolite repression. Polypeptides of 195 and 22 kDa were only observed in cells grown on maltose, whereas 88 kDa polypeptide was only observed in galactose‐grown cells. Among the calmodulin ‐binding polypeptides, eight were phosphorylated in a Ca2+ /calmodulin ‐dependent manner (220, 200, 175, 100, 62, 55, 31 and 16 kDa). Ca2+/calmodulin dependent [γ‐32P] incorporation was dramatically decreased in yeast cells submitted to a heat treatment.
Mössbauer spectroscopic study of the interaction of indole‐3‐acetic acid with iron(III) in aqueous solution
Authors: Kamnev Alexander A. , Kuzmann Ernö 
Published: July 2007

AbstractThe data of Mössbauer spectroscopic measurements in rapidly frozen 57FeIII nitrate solutions containing indole‐3‐acetic acid (IAA) are presented. The results obtained provide direct evidence that iron(III) is gradually reduced by IAA with the formation of soluble iron(II) complex. It has been found that further drying of the solution in air results in complete re‐oxidation of iron(II) with the formation of iron(III) complex. The structure of the complexes obtained and their possible role in solubilization and transformation of iron species in soil in the presence of IAA secreted by soil microorganisms into the environment are also discussed.
Aspects of glutamine metabolism in human tumour cells
Authors: Colquhoun Alison , Newsholme Eric A. 
Published: July 2007

AbstractThe importance of the non‐essential amino acid, glutamine, to the proliferation of human tumour cells was investigated. All of the cells studied had a high activity of phosphate‐dependent glutaminase and were found to utilise glutamine from the culture medium during long term culture. The rate of cell proliferation, determined by [6‐3H]‐thymidine incorporation, was dependent on glutamine concentration with the exception of Hs578T and MOLT 4 cells. The glutamine concentration giving half maximal growth (ED50 ranged from 0.02‐0.24mM. The glutamine analogue, acivicin [ L.(αS,5S)‐α‐amino‐3‐chloro‐4,5‐dihydro‐5‐isoxazoleacetic acid], markedly inhibited cell proliferation in the absence of glutamine. However, in the presence of glutamine acivicin only caused inhibition of proliferation in certain cell lines. Replacement of glutamine in the culture medium by glutamate resulted in an increase in the rate of cell proliferation when compared with rates in the absence of glutamine with no glutamate supplement. In addition, cells grown in the presence of the glutamine synthetase inhibitor, methionine sulphoximine, showed a marked decrease in proliferation. These data suggested the presence of glutamine synthetase in human tumour cells, which was confirmed by radiochemical assay of maximal glutamine synthetase activity. The breast tumour cells Hs578T, with high glutamine synthetase activity, were able to proliferate at rates similar to that in the presence of glutamine, when glutamine‐deficient medium was supplemented with purine nucleosides. However, the breast tumour cells MCF7, with low glutamine synthetase activity, were unable to proliferate at comparable rates in the presence of either purine or pyrimidine nucleoside supplements.
Increased longevity of kinetin‐fed Zaprionus fruitflies is accompanied by their reduced fecundity and enhanced catalase activity
Authors: Sharma Suraj P. , Kaur Jaspal , Rattan Suresh I. S. 
Published: July 2007

AbstractKinetin, a cytokinin plant growth hormone, retards senescence in plants, delays aging in human cells in culture, slows down development of insects and prolongs their lifespan. We have now observed that the increased longevity of Kn‐fed Zaprionus fruitflies was accompanied by an increase in the specific activity of catalase during developmental stages and in adult insects. In addition, the egg laying capacity of Kn‐fed fruitflies was reduced drastically as compared with those kept on a normal diet. These results support the view that improved maintenance of the soma and prolongation of its life is achieved at the cost of decreased reproductive activity.
Thromboxane A2 mediates cisplatin‐induced apoptosis of renal tubule cells
Authors: Jariyawat Surawat , Takeda Michio , Kobayashi Mami , Endou Hitoshi 
Published: July 2007

AbstractThe purpose of this study was to elucidate the role of thromboxane A2 (TXA2) in cisplatin‐induced apoptosis of mouse renal cells derived from the terminal proximal tubule (S3). RT‐PCR analysis revealed that S3 cells express TXA2 receptor mRNA. A TXA2 receptor antagonistKW‐3635, dose‐dependently inhibited cisplatin‐induced apoptosis of S3 cells. Treatment of S3 cells with a TXA2 agonist, STA2, induced a significant decrease in their viability and resulted in the characteristic ladder pattern resulting from intranucleosomal DNA cleavage. Treatment with KW‐3635 resulted in attenuation of the increase in c‐fos mRNA expression level in cisplatin‐treated S3 cells. In conclusion, TXA2 appears to mediate cisplatin‐induced apoptosis of S3 cells by inducing an increase in the level of c‐fos mRNA expression.
Purification, characterization, and expression of rat epididymal β‐D‐galactosidase
Authors: Hall Joseph C. , Jacobetz Dianne R. , LaMarche Mary D. , Kochins John G. , Tubbs Christopher E. 
Published: July 2007

AbstractThe purpose of the present study is to purify, kinetically characterize and measure the amount of soluble acid β‐D‐galactosidase (EC 3.2.1.23) in different anatomical regions (caput, corpus, and cauda) of the adult rat epididymis. Based upon SDS‐PAGE analysis, the subunit molecular mass of the caput and cauda enzyme is ∼85,000 daltons while the corpus enzyme is ∼50,000 daltons. The apparent Km and Vnmax values are 67, 24, and 59 μM and 5.0, 1.88, and 6.3 μM/min./‐mg protein for the enzyme purified from the caput, corpus, and cauda regions of the epididymis, respectively. However, no regional differences in the amount of soluble enzyme protein are observed. These data demonstrates regional differences in the activity of epididymal acid β‐D‐galactosidase and suggest that the observed regional differences in enzyme activity may be due to posttranslational modifications.
Unfolding and inactivation of penaeus penicillatus acid phosphatase during denaturation by guanidine hydrochloride
Authors: Chen Su‐Li , Chen Qing‐Xi , Yang Pei‐Zheng , Qiu Wen‐Jie , Wang Liao‐Teng , Zhou Hai‐Meng 
Published: July 2007

AbstractThe conformational changes of penaeus penicillatus acid phosphatase during denaturation in guanidine hydrochloride solutions were studied by following changes in the intrinsic fluorescence, ultraviolet difference absorption, and circular dichroism spectra. Inactivation of the enzyme in guanidine hydrochloride solutions were compared with unfolding of the enzyme molecule. The results show that the extent of unfolding in guanidine solutions measured by several different methods closely coincide with each other and that slightly lower concentrations of guanidine are required to bring about inactivation than are required to produce significant conformational changes of the enzyme molecule. At the same concentrations, the inactivation rate constants are markedly faster than the rate constants for unfolding of the enzyme. The above results suggest that the active sites of this enzyme display more conformational flexibility than the enzyme malecule as a whole.