bluuebunny/crossref_metadata_2025_split huggingface dataset:
Amino acid metabolism in the kidneys of genetic and nutritionally obese rats
Authors: Herrero M. Carmen , Remesar Xavier , Bladé Cinta , Arola Lluís 
Published: July 2007

AbstractThe ability of the kidney to take up and/or release amino acids has been determined in two models of obesity in Zucker rats, one genetic and the other nutritional (diet‐obese). There was a noticeable increase in gluconeogenic amino acids in the arterial blood of diet‐obese animals whereas the genetically obese rats showed small variations in the levels of these amino acids. There were significant decreases in renal Gly and Ser, only in the genetically obese rats. Genetically obese animals showed an increase in Glutamine synthetase activity. The uptake and/or release of amino acids showed important variations between the groups. The diet‐obese group exhibited greater variation, since this group took up Glu, Ala, Gy, Phe and Citrulline and released Gln, Ser, Arg and Tyr. Genetically obese rats took up Gln, His and Taurine and released Ser. These different patterns may be related to variations in the whole body metabolic rate, since the diet‐obese group was more active than the genetically obese group.
Ageing‐associated large‐scale deletions of mitochondrial DNA in human hair follicles
Authors: Kao Shu‐Huei , Liuz Ching‐San , Wang Shuo‐Yue , Wei Yau‐Huei 
Published: July 2007

AbstractHair follicles plucked from the bi‐temporal region of the scalp of 433 Chinese subjects of different ages were used for the examination of ageing‐associated mutations of human mitochondrial DNA (mtDNA). By use of PCR techniques, we detected the 4,977 bp and 7,436 bp deletions of mtDNA in hair follicles from aged individuals. The frequencies of occurrence of both mtDNA deletions were found to increase with age of the subject. Moreover, we employed a semi‐quantitative PCR method to determine the proportion of the 4,977 bp deleted mtDNA (dmtDNA) in hair follicles. The results showed that the average proportion of the 4,977 bp dmtDNA in hair follicles were 0.05%±0.01%, 0.00%, 0.55%±0.05%, 0.52%±0.24%, 0.65%±0.17%, 1.33%±0.25%, and 1.89%±0.81% for the subjects in the age groups of 21‐30, 31‐40, 41‐50, 51‐60, 61‐70, 71‐80, and 81‐99, respectively. Furthermore, we screened all the subjects harboring the 4,977 bp and/or 7,436 bp deletions for tandem duplications in the D‐loop region of mtDNA by PCR with back‐to‐back primers. The results showed that none of the previously reported tandem duplications were present in all the hair follicles examined. This indicates that tandem duplications do not predispose to large‐scale deletions of mtDNA. However, the data suggest that mtDNA deletions occur and accumulate in hair follicles during human ageing. As hair follicles can be easily and non‐invasively obtained from the human, we suggest that the age‐dependent accumulation of dmtDNAs in hair follicles may be used for the monitoring of human ageing process.
The control of oxygen affinity in the three human embryonic haemoglobins by respiration linked metabolites
Authors: Hofmann Oliver M. , Brittain Thomas , Wells Rufus M. G. 
Published: July 2007

AbstractThe effect of CO2, ATP and lactate ions on the oxygen affinity of the three human embryonic haemoglobins have been studied. CO2 lowers the affinity of both the adult and embryonic haemoglobins for oxygen, as does ATP. The ATP effect follows a simple binding process with an equilibrium constant in the mM range. Lactate ions have no effect on the oxygen equilibrium process, over the concentration range studied. These findings are discussed in terms of the likely physiological conditions experienced by human embryonic red blood cells.
Patterns of expression of Hoxa‐11 in micromass cultures of chick limb mesenchyme from various stages suggest a role for Hoxa‐11 in the specification of the zeugopod
Authors: Rogina Blanka 
Published: July 2007

AbstractDuring chick limb development the expression of Hoxa‐11 is specifically associated with the prospective zeugopod (radius+ulna) region. A series of micromass cultures were performed using mesenchyme from whole stage 18/19 or 20/21 limbs or mesenchyme from the tips of stage 22/23, 23/24 or 25 limbs. In such cultures, limb mesenchyme undergoes chondrogenesis paralleling its fate in vivo. Hoxa‐11 and collagen type II mRNA were examined by dot blot and in situ analysis at different time points. The highest level of Hoxa‐11 mRNA was found in micromass cultures of the tips of stage 22/23 and 23/24 limbs at 48 hours. Between stages 22 and 24, the determining events occur which subsequently lead to the formation of the zeugopod by the mesenchyme present in the tips at these stages. This correlation further supports a possible role of Hoxa‐11 in the specification of the zeugopod.
Autolytic activation mechanism of Bombyx acid cysteine protease (BCP)
Authors: Takahashi Susumu Y. , Yamamoto Yoshimi , Watabe Shoji , Kageyama Takashi 
Published: July 2007

AbstractAcid cysteine proteinase in the eggs of the silkmoth, Bombyx mori, exists as an inactive proenzyme. This 47‐kDa pro‐BCP1 zymogen molecule can be processed in vitro into an enzymatically active 39‐kDa BCP molecule (11, 12). In this current study, the maximum rate of processing in vitro was achieved at approximately pH 4.0, at a temperature of 37 °C under reducing conditions. The rate of conversion was not affected by increasing concentrations of pro‐BCP. We prepared immobilized BCP bound to AH‐Sepharose and examined the activation. Immobilized pro‐BCP was autolysed, although the rate of processing was slow, indicating that the reaction might be an intramolecular one. Kinetic experiments suggest that the mechanism is likely to involve a stepwise reaction, in which pro‐BCP is converted to an active enzyme through intermediate forms releasing small peptides stepwise.The results suggest that autocatalytic cleavage (intramolecular) is a major processing step in the early stage of pro‐BCP activation.
High level expression of recombinant plasminogen activator inhibitor‐1 in escherichia coli and generation of its mutants involving ASP125, GLU128 and GLU130
Authors: Sui Guang‐Chao , Sun Hong , Zhang Man , Hu Mei‐Hao 
Published: July 2007

AbstractPlasminogen activator inhibitor‐1 (PAI‐1) cDNA was expressed in Escherichia coli (E. coli) with high efficiency using a heat‐inducible vector. About 100 mg of recombinant PAI‐1 (rPAI‐1) could be obtained from 1 liter of bacteria culture, rPAI‐1 in inclusion bodies was purified by pI precipitation and Sephadex G‐75 chromatography. After treatment with 4 mol/L guanidinium chloride and dialysis, the largely inactive PAI‐1 gained considerably in activity as judged by its reaction with low molecular weight u‐PA (LMW‐u‐PA). Degenerated oligonucleotides containing ApaI site and mutations at Asp125, Glu128, Glu130 in PAI‐1 cDNA were synthesized. To facilitate the introduction of mutations, an ApaI site was first generated in PAI‐1 cDNA using one of the oligonucteotides. Taking advantage of the ApaI site, thirteen PAI‐1 mutants involving Asp125, Glu128 and Glu130 were produced with these oligonucleotides using PCR. Most of the PAI‐1 mutants had a similar activity as compared to wild type PAI‐1, while some of the triple‐site mutants had completely lost their activity.
Interactions between heparinoids and alcohol dehydrogenase
Authors: Paulíková Helena , Valusová Eva , Antalík Marián 
Published: July 2007

AbstractThe interaction between polysulfated polysaecharides (low‐molecular‐weight heparin LMWH, dextran sulfate DS and pentosan sulfate PS) and yeast alcohol dehydrogenase (YADH) was investigated. The fluorescence and UV spectra of YADH after adding the tested polysaccharides have confirmed the interaction between the enzyme and these compounds. Kinetic studies have shown that LMWH, DS and PS are inhibitors of YADH (mixed type with respect to NAD). The most potent inhibitor is PS (ID50=37.5 ng/ml, Ki=0.6 μM). The inhibition effect depends on the ionic strength (the inhibition decreased by about 50% in the presence of 100 mM Na2SO4) and pH value (the inhibition decreased at pH>7). The results indicate that the inhibition effect of these polyanions is caused by their electrostatic interactions with the NAD‐binding region of YADH.
Study of peptide‐protein interaction by high‐performance liquid chromatography. Effect of hydrophobic and steric parameters
Authors: Szikszay Zoltán , Forgács Esther 
Published: July 2007

AbstractThe interaction of 16 peptides was studied on zein‐coated silica column by high‐performance liquid chromatography. The separation factor, theoretical plate number and the asymmetry factors of the peaks were calculated. Stepwise regression analysis was applied to study the peptide‐protein interactions and to find the molecular substructures involved in the interactions and to define their character. Zein‐coated silica column was suitable for the determination of peptide‐protein interaction and the investigated peptide‐protein interactions were found to be mixed (hydrophobic and steric) character.
Studies on the catalytic activity of human hepatic porphobilinogen deaminase
Authors: Mazzetti Marta B. , Tomio J. María 
Published: July 2007

AbstractPorphobilinogen deaminase was purified from human hepatocytes. A variety of group specific reagents have been used to achieve site‐specific modifications to evaluate the potential role of such groups in the whole catalytic cycle. Treatment with dicarbonyl reagents caused a rapid loss in activity that was time and concentration, dependent. Protection experiments revealed that arginine residues are involved in the binding of the substrate. Treatment with Woodward's reagent K showed the fastest inactivation of deaminase (85% in 30 sec at 30mM) which was pH dependent and could be prevented by the presence of substrate, suggesting that deprotonated carboxylated groups from Asp/Glu are essential for catalytic activity. Kinetic analysis gave values of 0.3 sec‐1 for the k3 rate constant and 8×10‐2 M for the KI of the non covalent complex between deaminase‐Woodward's Reagent K
Reversible cell cycle arrest with concomitant p21/WAF1 overexpression and mitochondrial destruction by nitric oxide
Authors: Esumi Hiroyasu , Chin Keishou , Kurashima Yukiko , Hasegawa Fumio , Ogura Tsutomu , Yoneda Makoto , Ozawa Takayuki 
Published: July 2007

AbstractWhen human hepatocellular carcinoma Hep‐G2 cells were treated with the NO‐generating compounds, S‐nitroso‐N‐acetyl‐DL‐penicillamine(SNAP) or (±)‐(E)‐4‐ethyl‐2‐(E)‐hydroxyimino]‐5‐nitroso‐3‐hexenamide, cells stopped growing. Most cells were found to be in either G1 or G2/M phase and the dye‐exclusion test revealed that the cells were alive. Electron microscopic examination confirmed the integrity of cells and nuclei. Nuclear staining with the DNA‐binding dye H33258 revealed that cells did not undergo apoptosis although dramatic changes in mitochondrial morphology were noticed within 6 hr of treatment with SNAP by electron microscopy. Western and northern blot analysesrevealed that cells overexpressed p21/WAF1. The growth arrest was released by withdrawal of the NO‐generating compound and cells started to divide within 24 hr after withdrawal of the compounds.
Expression or possession of catalase gene does not alter the capacity of M. smegmatis to survive within human macrophages
Authors: Fazal Nadeem 
Published: July 2007

AbstractMycobacterium tuberculosis genes are expressed and screened in Mycobacterium smegmatis as a host, hence their survival in human monocytes needs to be determined. Strains of Mycobacterium smegmatis with an inactive catalase‐peroxidase gene (KatG), or into which the KatG gene of Mycobacterium tuberculosis had been transfected, were used to study the influence of catalase on intracellular mycobacterial survival within human monocyte‐derived macrophages. The five strains of Mycobacterium smegmatis were observed to grow at similar rates, irrespective of their catalase phenotype, within IFNγ‐treated or untreated human macrophage cultures, over a 3 day infection period. Moreover, there was no differential pattern of growth or inhibition among the strains of Mycobacterium smegmatis studied.
Characterization of Ca2 transport activity associated with a non‐mitochondrial calcium pool in the rodent malaria parasite P. chabaudi
Authors: Passos Ana P. D. , Garcia Célia R. S. 
Published: July 2007

AbstractNon‐mitochondrial calcium deposits were investigated in the intraerythrocytic malaria parasite Plasmodium chabaudi at the trophozoite stage by means of arsenazo III in the presence of ATP and the mitochondrial poisons, antimycin and ollgomycin. Addition of vanadate and 2,5‐di‐(t‐butyl)‐1,4‐hydroquinone (BHQ), both known to interact with SERCA pump, induced calcium release by permeabilized parasites when the medium free calcium concentration was kept at 3.5 μM. The tumor promoter thapsigargin also caused elevation of the free calcium concentration in permeabilized parasites. Our results support the view that P.chabaudi sequesters calcium in an exchangeable form and maintains its calcium homeostasis by way of an endoplasmic reticulum Ca2+ pump.
Oxidation of feric‐cytochrome c by N, N′‐bis (2‐hydroperoxy‐2‐methoxyethyl)‐1,4,5,8‐naphthalene tetracarboxylic diimide, NP III ‐ site specific modification of cytochrome c
Authors: Matsugo Seiichi , Yasui Fumihiko , Konishi Tetsuya 
Published: July 2007

AbstractWhen the synthetic hydroxyl radical generator, N, N′‐bis (2‐Hydroperoxy‐2‐methoxyethyl)‐1,4,5,8‐naphthalene‐tetracarboxylic diimide, NP III, was photoirradiated in the presence of ferric‐cytochrome c (Fe3 +), the fragmentation peak corresponding to the specific oxidative modification at the histidine site of cytochrome c was observed in the Matrix‐Assisted Laser Desorption Ionization‐Time of Flight Mass Spectroscopy (MALDI‐TOF) measurement. Without photoirradiation, no such protein oxidation was observed in the experimental conditions employed. This result suggests the possible usage of NP‐III as an oxidative protein‐modifying reagent.
Angiotensin II type I Receptor polymorphism in African Americans lower frequency of the C1166 variant
Authors: Gainer James V. , Hunley Tracy E. , Kon Valentina , Nadeau John H. , Muldowney James A. S. , Brown Nancy J. 
Published: July 2007

AbstractThe C1166 variant, an A to C substitution polymorphism at the 1166 position of the angiotensin II type I (AT1) receptor, has been previously associated with hypertension in Caucasians. This study determines the frequency of the C1166 variant in an African American population.Normotensive African American (n=99) and Caucasian (n=100) subjects were genotyped to determine the frequency of the C1166 variant. This study establishes the frequency of the C1166 variant in African Americans (0.05±0.01) and demonstrates a significantly lower frequency in African Americans compared with Caucasians (0.05 vs. 0.25, respectively, χ2=30.7, p<<0.001, 1 df).
Antagonistic regulation of protein kinase C‐induced stimulation of fibronectin synthesis by cyclic AMP in human lung fibroblasts
Authors: Lee Byung‐Heon , Park Rang‐Woon , Sohn Kun‐Young , Kim In‐San 
Published: July 2007

AbstractWe studied the interaction between cAMP and protein kinase C (PKC) signaling pathways in the regulation of fibronectin synthesis in human lung fibroblasts. Phorbol myristate acetate (PMA), a PKC activator, stimulated fibronectin synthesis and its mRNA expression in both normal and transformed human lung fibroblasts (WI‐38 and WI‐38 VA13, respectively). On the other hand, dibutyryl cAMP (Bt2cAMP), a cAMP analogue, did not alter fibronectin synthesis in both cell lines. The combined treatment of Bt2cAMP with PMA, however, suppressed the PMA‐induced stimulation of fibronectin synthesis and mRNA expression in these cells. This study shows that cAMP pathway antagonizes PKC pathway in regulating fibronectin synthesis in human lung fibroblasts and provides an example of antagonistic interaction between cAMP and PKC signaling pathways.
Single‐strand breaks and repair in nuclear DNA in the presence of hydralazine assayed by the nucleoid technique
Authors: Węglarz Ludmiła , Koceva‐Chyła Aneta , Drózdz Marian , Józwiak Zoifia 
Published: July 2007

AbstractThe nucleoid sedimentation assay was used to study hydralazine‐induced DNA structural changes and repair in the fibroblasts cultured in vitro. The drug induced a dose dependent loss in negative DNA supercoiling due to the physical breakage of the DNA. Relaxation of supercoiled DNA resulted in the nucleoids sedimenting with lower velocities than those of undamaged control cultures. Repair incubation of the cells did not cause the restoration of DNA supercoiling to control level. Unsuccessful repair of DNA damaged by hydralazine may result in maintaining the damaged DNA in the cell which could have immunologic consequences.
Development of a competitive enzyme linked immuno sorbent assay to measure α2‐macroglobulin in irradiated rat serum
Authors: Kim In Gyu , Park Seon Young 
Published: July 2007

AbstractA competitive enzyme linked immunosorbent assay with antigen immobilized on the solid phase was developed to measure α2‐macroglobulin in rat serum. The cross reactivity with albumin and hemoglobin was eliminated by use of IgG fractions that were isolated after chromatography on Cibacron Blue F3‐GA Sepharose immobilized rat whole serum and hemoglobin Sepharose. Blocking materials and pH of the coating buffer had no effect on the amount of α2‐macroglobulin that binds to the plate. When the coating amount of α2‐macroglobulin was 100 ng/well, at pH 7.4, 10 mM Tris‐HCl containing 150 mM sodium chloride and the IgG amount added was 60 ng/well, then albumin and hemoglobin did not affect the assay at concentrations of 150 μg/ml or 200 μg/ml. This assay is useful for measuring the concentration of α2‐macroglobulin in normal and irradiated rat serum.
Two short peptide sequences repeated three times in carrot /gb‐tubulin
Authors: Okamura Shoji , Sonehara Kazuhiko , Naito Keiko , Okahara Koichi 
Published: July 2007

AbstractThere are two repeated peptides, [S,T,Y]QQ[Y,M] and MFR[R,X][V,K], which appear three times each in the region corresponding to the third exon of carrot β‐tubulins. The former peptide is flanked on both sides by a pair of identically charged groups and the latter includes two or three basic amino acids in it. The sequences are generally conserved well among the eukaryotes except for fungi, in which one of the peptides, SQQY, does not exist.
Repetitive elements in the third intron of murine apolipoprotein A‐I gene
Authors: Chiang An‐Na , Fan Kong‐Chi , Shaw Gwo‐Chyuan , Yang Ueng‐Cheng 
Published: July 2007

AbstractGenomic DNAs containing the gene encoding apolipoprotein A‐I (apoA‐I) from four strains of mice and three strains of rats have been sequenced. Some peculiar repetitive sequences were found in the third intron of apoA‐I of the murine species. The striking features include regular tandem repeats of C(A)4 and C(A)6 in mice and long A‐tracts in rats. Not completely identical but very similar motifs were found in mice or rats belonging to the same species while repetitive elements from different species show some variation from their species‐specific consensus sequences. These repetitive motifs are very similar to the sequences flanking human Alu and rodent B 1 repetitive elements, although no evidence for the existence of Alu or B 1 was found near the peculiar repetitive DNA sequences in apoA‐I gene.
Role of transglutaminase in keratinization of vaginal epithelial cells in oestrous cycling rats
Authors: Vijayalakshmi V. , Gupta P. D. 
Published: July 2007

AbstractAspects of the regulation of calcium dependent transglutaminase (TGase) enzyme in the terminally differentiating vaginal epithelial cells (VEC) from cycling and oestradiol primed ovariectomized (OVX) rats are described. There is a significant increase in the TGase activity and a quantitative rise in its cross‐linked Σ(τ‐glutamyl)lysine covalent product in the VEC of oestrus rats. A similar phenomena was also evident in the oestradiol primed OVX rats. However, in the VEC of the diestrus/unprimed OVX rats, the enzyme activity and its cross‐linked product tend to be at its basal level. An increase of TGase activity in the keratinized layers of the oestrus VEC was observed. Immunohistochemical localization data parallel the biochemical measurements. These findings suggest that TGase activity may be associated with the differential status of the cell and primarily aids in the conferring structural stability and integrity to the stratified VEC. Aggregates of the keratin tonofilament bundles which are covalently cross‐linked by the formation of Σ(τ‐glutamyl)lysine in the oestrus vagina renders them resistant to denaturant and proteolytic treatments.
Antitumor activity of conjugates of the oncofetal protein alpha‐fetoprotein and phthalocyanines in vitro
Authors: Severin S. E. , Posypanova G. A. , Katukov V.Yu. , Shmyrev I. I. , Luzhkov Yu.M. , Gerasimova G. K. , Zhukova O. S. , Vorozhtsov G. N. , Kaliya O. L. , Lukyanets E. A. , Severin E. S. 
Published: July 2007

AbstractThe several conjugates of aluminium and cobalt complexes of phthalocyanines with human alpha‐fetoprotein have been synthesized. Their cytotoxic activity against tumor cells and human peripheral blood lymphocytes was studied. The experimental data demonstrate that the cytotoxic activity of alpha‐fetoprotein‐phthalocyanine conjugates against three types of tumor cells of various origin is much higher (for aluminium and cobalt complexes more than 1000 and 50 times, respectively) in comparison with phthalocyanines themselves. The application of phthalocyanines as conjugates with alpha‐fetoprotein makes it possible to markedly enhance the selective toxicity of phthalocyanines against human tumor cells.
Effect of calcium ion channel antagonists on chorionic gonadotropin secretion
Authors: Sharma Srikantaradhya Chidananda , Rao A. Jagannadha 
Published: July 2007

AbstractBy using calcium ion channel antagonists such as Verapamil and Nifedipine, we demonstrated that calcium ion channels are involved in human chorionie gonadotropin (hCG) secretion stimulated by gonadotropin releasing hormone (GnRH). Addition of 1 μM Verapamil (Class II inhibitor) resulted in an inhibition of GnRH‐stimulated hCG secretion by placenta without affecting basal release. However, while addition of 10 μM Niffedipine (Class I inhibitor) resulted only in partial inhibition, significant inhibition was observed at 100 μM concentration and above. These results suggest that calcium ion channels in placenta appear to be similar although not identical with the channels reported in the pituitary.
Cytoplasmic creatine kinases from giant pandas
Authors: Wang Xi‐Cheng , Ye Ju‐Qun , Wang Hong‐Rui , Zhou Hai‐Meng 
Published: July 2007

AbstractThe muscle and brain creatine kinases of giant panda have been isolated and purified. The purified muscle and brain enzymes (MM and BB) are homogeneous on both the polyacrylamide gel electrophoresis in the presence and absence of SDS. Both enzymes are dimers, consisting of two identical subunits each with a molecular weight of 42,000 daltons. The characteristics of muscle and brain enzymes have been studied, respectively. The hybridized enzyme, MB, was prepared by hybridization of MM and BB. The kinetic parameters of MM, BB and MB were determined, respectively. The results from modification of SH groups show that the SH groups of panda creatine kinases are essential for their activity and among the all SH groups in the enzyme only one per subunit is essential for enzymatic activity.