bluuebunny/crossref_metadata_2025_split huggingface dataset:
Isolation of intact transition protein 2 with three zinc finger motifs from boar late spermatid nuclei
Authors: Akama Kuniko , Sato Hiroki , Oguma Koichi , Nakano Minoru 
Published: July 2007

AbstractBoar intact transition protein 2, TP2, was isolated from the late spermatid nuclei by chromatography on Fractogel EMD SO3‐ 650 (M), and HPLCs on Nucleosil 300 7C18, Diol‐120 and Chemcosorb 3C18H. CD spectroscopy study showed that TP2 underwent a small but significant zinc dependent secondary structural change. TP2, having three potential zinc finger motifs, was shown to be contain 3 atoms of zinc bound per molecule of the protein by atomic absorption spectroscopy. These results together with the amino acid sequence of TP2 suggest that TP2 is a zinc metalloprotein with three zinc finger structures.
Fusion of phospholipid vesicles induced by the ribosome inactivating protein saporin
Authors: Liu Guohong , Hao Qiang , Zhang Yah , Gao Gui , Yan Ganglin , Yao Qizhi , Li Qingshan 
Published: July 2007

AbstractThe single chain ribosome‐inactivating protein Saporin‐S6 (SO‐6) induces the fusion of acid phospholipid vesicles. The extent of fusion was measured by resonance energy transfer assay between the N‐(7‐nitro‐2‐1,3‐benzoxadiazol‐4‐yl)‐dimyristoylphosphatidyl lithanolamine (NBD‐PE)(donor) and N‐(lissamine rhodamine B sulphonyl)‐diacylphoshaidylethanolamine (Rh‐PE) (acceptor) incorporated in the vesicle. The saturated lipid/protein molar ratio is approx. 100:1. The time course of fusion of vesicles induced by the protein showed that the process was completed within 10 minutes, and the size of the particles in the medium was enlarged which conforms the occurrence of the fusion occuring. The fusion is temperature dependent and the liquid‐crystalline state lipid is more apt to fuse than the gel phase lipid. The effect of SO‐6 is also dependent on ionic strength and pH, high salt concentration and basic pH may abolish fusion, which suggests that both electrostatic and hydrophobic components may be involved in the process.
The transcriptional repression of the human Cu/Zn superoxide dismutase(sod1) gene by the aticancer drugg, mitocycin C(MMC)
Authors: Cho Ginam , Kang Sangsun , Seo Seong Jin , Kim Younhee , Jung Guhung 
Published: July 2007

AbstractThe Cu/Zn superoxide dismutase(sod1) is one of the key enzymes that protects cells against oxidative stress. In order to investigate the effects of mitomycin C(MMC) on the induction of apoptotic cell death and on the sod1 transcription level, the CATs activity of HepG2 cells transfected with sod1 promoter‐CAT(chloramphenicol acetyl transferase) fusion reporter was measured after MMC treatment. The CAT assay showed that exposure of HepG2 cells to MMC decreased the transcription level of the sod1 gene. The accumulation of p53 tumor suppressor protein by MMC treatment of HepG2 cells was noted. In order to investigate the p53‐negative response element in its promoter region, a p53 cotransfection experiment with serially deleted sod1 promoter/CAT reporter constructs was performed. The results show a significant reduction of CAT activity in all deletion reporter constructs. The results show that MMC treatment inhibited sod1 gene transcription through p53‐mediated transcriptional repression.
Autolytic site mutant R105C of rat trypsin
Authors: Li Xin‐Fang , Tang Jian‐Guo , Zhang Long‐Xiang 
Published: July 2007

AbstractThe autolytic site Argl05 of rat trypsin was replaced with Cys by DNA site‐directed mutagenesis method. Comparison of expression and purification of R105C trypsin along with the wild type and some other Arg105 mutants indicates that R105C trypsin could be expressed as well but with a lower expression level. It is unexpected that R105C trypsin has no detectable activity toward trypsin substrate TAME, quite different from the wild type and other Argl05 mutants. Native gel electrophoresis analysis indicates that R105C trypsin has a similar mobility rate to that of wild type trypsin. FPLC also gives similar retaining time. The loss of activity of R105C trypsin may result from the conformational change around active site, but not the dimer formation.
Oxidized low‐density‐lipoprotein triggers programmed death of endothelial cells
Authors: Seelos Christian , Gmeiner Bernhard , Kapiotis Stylianos , Cerni Christa 
Published: July 2007

AbstractIncubation of bovine aortic as well as human umbilical vein endothelial cells with either oxidized or native low‐density‐lipoprotein in the presence of trace amounts of copper induced morphological changes of the cells and chromatin fragmentation characteristic for programmed cell death. Shrinkage of cells was evident after 6 to 8 hours of incubation and clearly preceded release of lactate dehydrogenase as a marker of cell permeability. Condensation of nuclear chromatin and internucleosomal cleavage was demonstrated by Hoechst staining and gel electrophoresis, respectively. Thus, by inducing active death of endothelial cells oxidized low‐density‐lipoprotein might negatively influence tissue homeostasis of the endothelium and thereby promote the development of atherosclerotic plaques.
Occurrence of nonenzymatic N‐acetylation of sphinganine with acetyl coenzyme a producing C2‐H2‐ceramide and its inconvertibility to apoptotic C2‐ceramide
Authors: Kashiwagi Motoi , Mikami Takeshi , Chiba Masahiko , Chiba Susumu , Matsumoto Hiroyuki , Akino Toyoaki , Gasaa Shinsei 
Published: July 2007

AbstractSphinganine, a biosynthetic precursor of ceramide, was non‐enzymatically acetylated with acetyl coenzyme A at the C‐2‐amino residue to produce C2‐H2‐ceramide (N‐acetyl sphinganine) in an organic solvent and in an aqueous solution with a high yield, where as sphingenine was only acetylated slightly. The structure of the N‐acetyl sphinganine was identified with mass spectrum, and with chromatography using an authentic N‐acetylated substance. Furthermore, the C2‐H2‐ceramide was examined for enzymatic desaturation to determine whether C2‐ceramide, a cell‐permeable ceramide responsible for apoptosis of cells, was produced, revealing an inferior substrate for H2‐ceramide desaturase of horse brain microsomes.
Identification, purification, and partial characterization of a factor from rabbit serum that inhibits prolactin secretion by pituitary cells cultured in vitro
Authors: Giacomelli Sabrina , Cheng C. Yan , Leone Maria Grazia , Palmery Maura , Silvestrini Bruno 
Published: July 2007

AbstractA biological factor that inhibited prolactin secretion by pituitary cells cultured in vitro was identified, purified, and partially characterized from normal rabbit serum. This biological factor was also found to potentiate dopamine‐mediated aortic contraction using rabbit aortic strips in vitro. Following SDS‐PAGE, this factor displayed an apparent Mr of 17 kDa, which is different from the Mr of most known endogenous factors having an inhibiting activity on pituitary prolactin secretion, suggesting that this may be a yet‐to‐be identified novel molecule.
Characterization of the orf31‐petG gene cluster from the plastid genome of Populus deltoides
Authors: Naithani Sushma , Trivedi Prabodh K. , Sane Prafullachandra V. 
Published: July 2007

AbstractThe orf31‐petG gene cluster is located approximately 1.2 kb away from the psbEFLJ operon in the chloroplast genome of Populus deltoides. The orf31 (ycf7 encodes an unidentified polypeptide while the petG gene encodes subunit V of an important component, cytochrome b6/f complex, involved in photosynthetic electron transport. We have determined the nucleotide sequence of the orf31‐petG gene cluster from the plastid geneme of a tree, Populus deltoides. Our sequence analysis suggests that these genes possess high homology with the published sequences of these genes from other plants. Northern analysis suggests development dependent transcription of the orf31‐petG cluster in leaves.
Comparison of SSCP analysis and CFLP analysis for mutation detection in the human iduronate 2‐sulfatase gene
Authors: Maddox Lewis O. , Li Peining , Bennett Amy , Descartes Maria , Thompson Jerry N. 
Published: July 2007

AbstractScanning methodologies are used for the identification of DNA fragments that differ from the normal nucleotide sequence. Fragments that produce abnormal band patterns are sequenced for characterization of the exact mutation. Factors considered in choosing a scanning methodology include reproducibility, sensitivity, and time. In the present study, we compared single‐stranded conformational polymorphism (SSCP) and Cleavase fragment length polymorphism (CFLP) methodologies for mutation scanning of exon VIII in the iduronate 2‐sulfatase (IDS) gene. Mutations of the IDS gene result in an X‐linked lysosomal storage disease, Hunter syndrome. These six known mutations analyzed by the two methods included a one base pair deletion, a one base pair insertion, and four point mutations. SSCP analysis detected all of the mutations and CFLP analysis detected three of the six mutations. We concluded that SSCP analysis was preferable to CFLP analysis for scanning exon VIII in the IDS gene for mutations.
The differential in vitro stimulation of 3′,5′‐cyclic nucleotide phosphodiesterase by calcium binding proteins
Authors: La Bella Vincenzo , Ho Bao‐Kuang , Appel Stanley H. 
Published: July 2007

AbstractA eterogeneous class of proteins exhibit within their sequence a particular structure, named EF‐hand, able to bind calcium with high affinity. These calcium binding proteins have been described in most cells and tissues and are suggested to work as calcium buffers, thereby participating in the regulation of calcium‐dependent cellular activity. Recent circumstantial evidences suggest that calcium binding proteins may serve other functions as well, possibly as enzyme modulators. Since 3′,5′‐cyclic nucleotide phosphodiesterase is a well‐known calmodulin‐modulated enzyme, in this work we studied the effect in vitro of different purified calcium binding proteins on the activity of this enzyme. Among the proteins tested, calmodulin and recombinant rat brain parvalbumin could stimulate the 3′,5′‐cyclic nucleotide phosphodiesterase activity in vitro, whereas rabbit muscle parvalbumin, rat renal and brain calbindin D28K, and bovine brain S‐100B were ineffective. Immunoprecipitation with the specific antiserum completely abolished either calmodulin or recombinant brain parvalbumin activation of 3′,5′‐cyclic nucleotide phosphodiesterase. Moreover, while the presence of calcium in the incubation mixture was critical in the calmodulin‐mediated stimulation of the enzyme, it did not modify the effect of the recombinant brain parvalbumin. We suggest that, in addition to calmodulin, parvalbumin may be a regulator of 3′,5′‐cyclic nucleotide phosphodiesterase, and possibly of other yet to be identified enzymes in certain tissues.
Biochemical properties of hemagglutinins in the mollusk Pomacea flagellata
Authors: Arreguín‐Espinosa Roberto , Arreguín‐Lozano Barbarín 
Published: July 2007

AbstractExtracts of the Mollusk Pomacea flagellata were found to contain two agglutinins (PFA‐I and PFA‐II) which reacted with erythrocytes from human and several animal species. The hemagglutinating activity was stable between pH 4.0 and pH 10.0, and was independent of divalent cations. The active components were purified and found to be glycoproteins having Mr of 30,000. The isoelectric points were estimated to be 4.7 and 4.9 for PFA‐I and PFA‐II respectively. Hapten inhibition assays indicated that the agglutinin and its isoforms are specific for β‐galactosides as well as for galactose containing glycoproteins.
Conformational changes of creatine kinase in trifluoroethanol solutions
Authors: Yang Hai‐Peng , Zhou Hai‐Meng 
Published: July 2007

AbstractThe conformational changes of creatine kinase (ATP:creatine N‐phosphotrnsferase, EC 2.7.3.2) in trifluoroethanol solutions have been followed by fuorescence emission and circular dichroism spectra. At low trifluoroethanol concentrations, less than 15%, the enzyme was completely inactivated with no observed marked conformational changes. The fluorescence emission maximum of the native enzyme was at 337 nm. With increasing trifluoroethanol concentration, the fluorescence emission maximum red‐shifted in magnitude to a maximum value (355nm) at 40% trifluoroethanol, indicating that the tryptophan residues were completely exposed. The results obtained from CD spectra show that the presence of trifluoroethanol can induce the formation of secondary structure in the native enzyme and in urea‐denatured enzyme.
Enhanced expression of initiator tRNAMet in human gastric and colorectal carcinoma
Authors: Kanduc Darja , Lucchese Alberta , Corcia Maria Grazia di , Natale Costanzo 
Published: July 2007

AbstractTransfer RNA isoaccepting species are differentially expressed at different times during development, differentiation, growth, aging, and carcinogenesis processes. It has been suggested that alterations in tRNA patterns might be mechanistically important in modulating gene expression during the various physiological/pathological cellular stages. As part of a study to investigate the possible mechanisms by which alterations of translational machinery can start and/or sustain carcinogenic cell proliferation, in this communication we report analysis of tRNA distribution in two gastro‐intestinal human tumors. The qualitative and quantitative data obtained for cellular tRNA distribution put into evidence a shift in the tRNA population with increased level of initiator tRNAMet in the malignant tissues. This observation confirms previous data obtained on experimental carcinogenesis models and suggests the possibility of specific involvement of tRNA changes in protein synthesis initiation during tumorigenesis.
The role of acetic acid in the prevention of salt‐induced aggregation of snake venom cardiotoxins
Authors: Sivaraman T. , Kumar T. K. S. , Huang C. C. , Yu C. 
Published: July 2007

AbstractSnake venom cardiotoxins (CTXs) exhibit a strong tendency to aggregate upon desalting and hence it is extremely difficult to prepare salt‐free cardiotoxin(s). In the present study, we describe a new method for preparation of salt‐free CTX based on dialysis against acetic acid. Based on experimental observation and the three dimensional solution structure of cardiotoxin analogue III from the Taiwan cobra (Naja naja atra), a molecular mechanism for the prevention of aggregation of cardiotoxins by acetic acid is discussed. In our opinion, the results obtained in the present study would pave way for elucidating the structural basis for the broad spectrum of biological activities exhibited by snake venom cardiotoxins.
Compromised optimal hybridization temperatures may explain PM plus DQA1 anomalies
Authors: Riley Donald E. 
Published: July 2007

AbstractThe multiplex DNA typing test kit, PM plus DQA1TM relies on 36 different olignucleotides that all must hybridize correctly for accurate DNA typing. The G+C contents of the probe oligonucleotides range from 47% to 83%. Since G+C content directly affects optimal hybridization temperatures, a wide range of optimal hybridization temperatures is expected. This was verified by two empirically tested formulas. The recommended hybridization temperature is 55°C. The control probe has an estimated optimal temperature of 75°C indicating low stringency of the control. The B allele probe of the GC locus has an estimated optimal hybridization temperature of 70°C. These discrepancies are unexplained by GC clusters or sequence palindromes. The departures from temperature optima may be responsible for observed PM plus DQA1 artifacts and for previously observed, low tolerance of this system to temperature variation. Since optimal temperature and cation concentration are related variables, careful attention to these is recommended as are positive controls demonstrating amplification of all alleles monitored by PM plus DQA1.
A surface plasmon resonance assay for the binding of Amaranthus hypochondriacus var. Mexico lectin to glycoprotein
Authors: Ozeki Munetaka , Furuichi Yukio , Umekawa Hayato , Takahashi Takao 
Published: July 2007

AbstractWe have used the analytical system based on surface plasmon resonance to monitor the interaction between Amaranthus hypochondriacus var. Mexico lectin and four different fetuins; fetuin, asialofetuin, agalactofetuin, and agalactosaminofetuin. Agalactofetuin and agalactosaminofetuin were prepared by enzymic digestion of asialofetuin using jack bean β‐galactosidase or endo‐α‐N‐acetylgalactosaminidase from Diplococcus pneumoniae. Ligands were immobilized onto a sensor surface via amide linkages. The lectin interacted most strongly with asialofetuin, but not with agalactosaminofetuin. The binding of the lectin to asialofetuin was inhibited by N‐acetylgalactosamine or Galβ1→3GalNAc in a dose‐dependent manner.
Increment of efficiency in the identification of noble genes by colony hybridization assay
Authors: Kim J. W. , Lee I. A. , Lee Y. H. , Song J. C. , Choe Y. K. , Hahn Y. S. , Chung J. H. , Chung T. W. , Choe I. S. 
Published: July 2007

AbstractFor the rapid identification of noble genes in a specific tissue by computer analysis from the cDNA sequences determined by single‐pass cDNA sequencing, clone redundancy was one of the major obstacles. To facilitate the efficiency in identification of noble genes, it was necessary to reduce the number of clones to be sequenced by eliminating the redundant clones for a rapid analysis. In order to increase the probability of isolating noble sequences from the cDNA clones of human fetal liver tissue origin, colony hybridization assay was adopted and redundant clones were efficiently removed. Four cDNA clones highly redundant in the human fetal liver cDNA libraries including α‐globin, γ‐globin, serum albumin and H19 RNA sequences were selected as the probes. Two hundreds and sixty two cDNA clones were randomly selected and tested with the probes for hybridization properties. The identity of each cDNA clone giving positive or negative signals in the hybridization assay was determined by DNA homology search with the nucleic acid databases. Among the 76 clones giving positive signals, 57 clones (75%) were found to be identical to the probe sequences and could be eliminated by colony hybridization assay before neucleotide sequencing.
Mapping of quantitative trait loci for body weight on chromosomes 1 and 4 in the rat
Authors: Kovács Peter , Klöting Ingrid 
Published: July 2007

AbstractQuantitative trait loci (QTLs) affecting body weight were investigated in the backcross population derived from diabetic BB/OK and spontaneously hypertensive rat (SHR). The F1 hybrids were backcrossed onto BB/OK rats, and QTL analysis was performed with the resulting backcross population on chromosomes 1, 3, 4, 10, 13 and 18. According to the stringent threshold for a lod score of 3.0, markers on chromosomes 1 and 4 were found to be linked with body weight. The QTL with a peak lod score (3.3) on chromosome 1 for a male population was located within the region flanked by loci Igf2 and D1Mgh12. On chromosome 4, linkage between the body weight and the region around the Npy locus was observed (lod score 3.1). The existence of the QTL on chromosome 4 affecting body weight was confirmed by congenic BB.LL rats, carrying chromosomal region of SHR (D4Mit6‐Npy‐Spr) on the genetic background of the BB/OK rat.
Isolation and characterization of CspBI, a novel NotI isoschizomer from Corynebacterium species B recognizing 5′‐GC↓GGCCGC‐3′
Authors: Sokolov Nikolai N. , Eldarov Michael A. , Rina Mary , Korolev Sergey V. , Markaki Maria , Kalugin Alexei A. , Omelyanuk Natalia M. , Skryabin Konstantin G. , Bouriotis Vassilis 
Published: July 2007

AbstractSixty‐seven bacterial strains were surveyed for the presence of type II restriction endonucleases, especially concerning super‐rare‐cutting enzymes. Fourteen strains were found to contain specific enzymes. One of them CspBI from Corynebacterium species B was purified and characterized as an isoschizomer of NotI, which recognizes the palindromic octanucleotide sequence 5′‐GC↓GGCCGC‐3′ and cleaves at the position shown by the arrow. A comparison between the cleavage patterns on different DNAs, obtained with partially purified endonucleases from other detected producents including some strains of Corynebacterium, Cellulomonas and Rhizobium has shown that these enzymes do not belong to super‐rare‐cutting restriction endonucleases.
Cross‐linking induces homodimer formation and inhibits enzymatic activity of chicken stomach ecto‐aryrase
Authors: Carl Stephanie Ann Lewis , Smith Thomas M. , Kirley Terence L. 
Published: July 2007

AbstractWe have investigated the effect of cross‐linking on the enzymatic activity and oligomer formation of the chicken stomach ecto‐apyrase. Cross‐linking with the hydrophobic, lysine‐specific dithiobis(succinimidylpropionate) (DSP) caused equal inhibition of ATPase and ADPase activity in both the membrane‐bound and detergent‐solubilized ecto‐apyrase. The inhibitory effect of cross‐linking was reversed upon the addition of the reductant dithiothreitol. Western blots of aliquots of the cross‐linked samples show decreased amounts of the monomeric 80 kDa ecto‐apyrase and the appearance of a 160 kDa dimer under conditions inducing enzyme inhibition. Therefore, the chicken stomach ecto‐apyrase, like the chicken gizzard ecto‐ATPase, is likely a homodimer in vivo. Unlike the related gizzard ecto‐ATPase, however, the native stomach ecto‐apyrase is not stimulated, but rather inhibited by cross‐linking, presumably due to different quaternary structural stability of the two enzymes.
Carbohydrates regulate the dimerization of angiotensin‐converting enzyme
Authors: Kost Olga A. , Orth Tatyana A. , Nikolskaya Irina I. , Nametkin Sergei N. , Levashov Andrey V. 
Published: July 2007

AbstractSummary. Regulation of the catalytic activity and supramolecular structure of angiotensin‐converting enzyme was studied in reverse micelles of Aerosol OT in octane as biomembrane model. The kinetic experiments and the sedimentation analysis demonstrated that the enzyme can function both in monomeric and dimeric form. The degree of dimerization was strongly dependent on the concentration and structure of mono‐ and disaccharides added to the media, indicating the specific role of carbohydrates in forming the supramolecular structure of angiotensin‐converting enzyme. The existence of carbohydrate‐binding center on the enzyme molecule is proposed.
Saccharide‐assisted delivery of cytotoxic liposomes to human malignant cells
Authors: Vodovozova Elena L. , Gayenko Galina P. , Razinkov Vladimir I. , Korchagina Elena Yu. , Bovin Nikolai V. , Molotkovsky Julian G. 
Published: July 2007

AbstractThe overexpression of lectins by malignant cells was applied for in vitro targeting of liposomes equipped with a saccharide vector and loaded in the lipid phase with a lipid derivative of anticancer agent sarcotysine. The lectin specificity of human leukemia HL‐60 and human lung adenocarcinoma ACL cells was revealed by tests with fluorescein‐labeled sugar probes. With the help of fluorescent lipid dye it was shown that active saccharide ligands increased the level of the vectored liposome binding to malignant cells by 50‐80% as compared to liposomes without vector or with inactive one. The degree of liposome/cell membrane fusion was monitored fluorometrically and was shown to be complete and independent of the vectors. The targeted drug‐loaded liposomes had the cytotoxic activity 2‐4 times higher as compared to the vector‐free ones.