bluuebunny/crossref_metadata_2025_split huggingface dataset:
Concanavalin A binding to oligosaccharide chain leads to alterations in properties of Band 3
Authors: Zhang Zhen‐Gang , Lu Jing‐Ze , Chen Jian‐Wen 
Published: July 2007

AbstractAnion transport activity and thermotropic behavior of Band 3 are found to be altered after binding of concanavalin (Con A) to human erythrocyte ghosts and isolated Band 3. At lower Con A concentration, the rate coefficients of anion transport enhance with increasing Con A concentration, while noticeable changes of the largest calorimetric endotherm of human erythrocyte membranes termed the C transition (Band 3) can not be observed. With 50μg/ml of Con A, the rate coefficient of Con A‐modified ghosts increases 34.4% in comparison with that of normal ghosts. Binding of Con A in lower concentration to ghosts bring about increase of fluidity of lipid which maybe contribute to increase anion transport via Band 3. At higher Con A concentration, the C transition tend to lower temperature with increase in Con A concentration. the C transition is shifted from 69.25°C to 66.25°C with 2.5mg/ml Con A. It is suggested that the Con A‐modified Band 3 possess a looser structure than normal one.
Modulation by nitric oxide (NO) of capsaicin‐induced calcium uptake into rat dorsal root ganglion neurons
Authors: Park Young‐Ho , Surh Young‐Joon , Lee Sang‐Sup 
Published: July 2007

AbstractThe regulatory role of nitric oxide in capsaicin‐induced 45Ca2+ accumulation in dorsal root ganglion neuronal cultures was investigated. Capsaicin‐activated calcium entry was subject to complicated tuning by NO‐releasing agents sodium nitroprusside, spermine/NO complex and NO synthase inhibitor NG‐nitro‐L‐arginine methyl ester in concentration and stimulation protocol‐dependent manner. In contrast, these agents failed to change depolarization‐induced calcium influx. In experiments using dithiothreitol and 5,5‐dithio‐bis‐2‐nitrobenzoic acid this modulation was independent of the oxidizing action of NO. It is suggested that NO exerts a novel feedback modulatory effects on capsaicin‐induced calcium entry into rat DRG neurons.
Cloning and characterization of the non‐catalytic heavy chain of mouse complement factor I gene: Structure comparison with the human homologue
Authors: Yun Young‐Sup , Goldberger Gabriel , Minta Joe O. 
Published: July 2007

AbstractThe gene sequence encoding the non‐catalytic heavy chain of mouse complement factor I (mCFI) was cloned and its exon‐intron organization and domain structure characterized. The genomic organization of mCFI differs in several aspects from its human homologue (hCFI). The intron sizes are remarkably different. Exons 2 and 4 in mCFI are larger than their counterparts in hCFI by 9 bp and 6 bp respectively. Whereas the diversity (D) region of hCFI is encoded by two exons (exon 7 or hD2 and exon 8 or hD4), this region in mCFI is encoded by three exons; exon 6A or mD1 (located at the 3′‐end of the LDLr A2 domain), exon 7 or mD2 and exon 8, an extended exon (56 bp) composed of mD3, fused upstream of mD4. In contrast, hCFI lacks D1 and D3 subregions and exon 8 in hCFI consists of only hD4, 36 bp in length. Thus the heavy chain of mCFI is organized into 10 exons compared to 9 exons in hCFI.
Introduction of NAD decreases fMLP‐induced actin polymerization in chicken polymorphonuclear leukocytes ‐ The role of intracellular ADP‐ribosylation of actin for cytoskeletal organization
Authors: Terashima Masaharu , Shimoyama Makoto , Tsuchiya Mikako 
Published: July 2007

AbstractWe reported previously that the arginine‐specific. ADP‐ribosyltransferase in chicken polymorphonuclear leukocytes specifically modified actin, thereby inhibiting actin polymerization in vitro. In the present study, we investigated the effect of ADP‐ribosylation on actin polymerization in situ. In the leukocytes, the introduction of NAD inhibited the increase in filamentous actin contents induced by a chemotactic peptide formyl‐methionyl‐leucyl‐phenylalanine, while introduction of NAD together with novobiocin, a specific inhibitor for ADP‐ribosyltransferase, did not. These results suggest that ADP‐ribosylation regulates the formation of filamentous actin by the covalent modification of the protein in vivo.
Polymerization of actin induced by a molar excess of ATP in a low salt buffer
Authors: Ikkai Takamitsu , Kondo Hiroshi 
Published: July 2007

AbstractThe polymerization of actin induced by dilution has previously been reported, where a 1000‐fold molar excess of ATP over actin resulted when actin was diluted to 4.0 μg/ml in low salt buffer A (0.1 mM ATP, 0.1 mM CaCl2, 2 mM Tris‐HCl, pH 8.0, 5 mM 2‐mercaptoethanol, 1 mM NaN3). Filaments formed by the addition of ATP to a 1000‐fold molar excess over actin in buffer B (0.1 mM CaCl2, 2 mM Tris‐HCl, pH 8.0, 1 mM NaN3) were then separated by gel‐filtration. When ATP was removed from these filaments using Dowex‐1, depolymerization occurred. Thus, the reversible polymerization induced by the dilution of actin or by addition of ATP can be ascribed to the binding of ATP at the low affinity site of actin.
C‐terminal region of hTPO is important for secretion and expression in insect cells
Authors: Man Hyea Kyung , Chung Joo Young , Park Sang Kyu , Joo Semg Myung , Park Seung Kook , Koh Yeo Wook 
Published: July 2007

AbstractHuman thrombopoietin (hTPO) variant cDNAs truncated in the C‐terminal regions of wild‐type hTPO (332 amino acids) were constructed by PCR and expressed in Trichoplusia ni (Tn5) insect cells using a baculovirus expression system. Each variant, hTPO163 (amino acids 1‐163), hTPO198 (1‐198) and hTPO245 (1‐245), was produced in insect cells with very low efficiency in comparison with wild‐type hTPO. Immunoblot analysis showed that the predicted 20, 25 and 34 kDa molecular sizes corresponding to hTPO163, hTPO198 and hTPO245, respectively, were barely detected in culture medium and most of the proteins remained within the cell. These results suggest that C‐terminal regions containing potential N‐glycosylation sites of hTPO are required for the secretion of hTPO into culture medium as well as expression in insect cells.
Phenotypic selection: A successful strategy to fix major genes of hypertension
Authors: Klöting Ingrid , Kovács Peter , Brandt Jens van den 
Published: July 2007

AbstractHypertension is dominantly inherited in cross hybrids between hypertensive SHR/Mol and normotensive BB/OK rats. We used these cross hybrids for repeated backcrossing of selected hypertensive animals onto normotensive BB/OK rats to fix high blood pressure and to generate a hypertensive and diabetic BB/OK rat subline. After 8 backcrosses, the backcross parents were genetically analysed with the aid of 259 microsatellite markers to identify SHR genes causing blood pressure of 177±10 mmHg in this BB/OK rat subline. Loci on chromosomes 1, 14 and 18 showed longest heterozygosity. These loci might contain major genes of the SHR rat causing hypertension in this BB/OK rat subline. This classical strategy seems to be most suitable to fix major genes of hypertension in particular and complex traits in general and therefore to generate new animal models.
Nucleoid proteins of pea chloroplasts: detection of a protein homologous to ribosomal protein
Authors: Oleskina Yu.P. , Yurina N. P. , Odintsova T. I. , Egorov Ts. A. , Otto A. , Wittmeann‐Liebold B. , Odintsova M. S. 
Published: July 2007

AbstractBasic proteins were isolated from purified pea chloroplast nucleoids by acid extraction. Using RP‐HPLC, the component composition of the basic proteins was studied. SDS‐PAGE of major HPLC‐fractions showed that the basic nucleoid proteins are heterogeneous with mol. masses of components from 17 to 30 kDa. One polypeptide with mol. mass of 28 kDa (P28) was obtained by RP‐HPLC. The sequencing of three tryptic peptides of P28 (T6, T17, and T19) showed that they are homologous to the ribosomal protein L19 of Saccharomyces cerevisiae. The possible functional role of ribosomal proteins in chloroplast nucleoids is discussed.
Mitochondrial changes during the apoptotic process of HeLa cells exposed to cisplatin
Authors: Melendez‐Zajgla Jorge , Cruz Elizabeth , Maldonado Vihma , Espinoza Ana Maria 
Published: July 2007

AbstractHeLa cells undergo apoptosis after exposure to cisplatin. Since mitochondria have recently been proposed as a probable effector of this type of cell death, we performed an analysis using the fluorescent cation rhodamine 123, which is transported actively by this organelle. Cisplatin induces a decrease in the mitochondrial staining, as assessed by cytofluorometric analysis. Microscopic analysis demonstrated that this effect was accompanied by damage of the mitochondria. These features were not exclusive of cisplatin, as other antineoplasic agents (taxol, etoposide) elicited similar effects. These results point toward the notion of a general effect of antineoplasic drugs over the mitochondria during induction of apoptotic cell death.
Induction of apoptosis by selenite and selenodiglutathione in HL‐60 cells: Correlation with cytotoxicity
Authors: Cho Dae‐Yeon , Jung Uhee , Chung An‐Sik 
Published: July 2007

AbstractEffects of selenite and selenodiglutathione, an initial metabolite of selenite, on the induction of apoptosis and cytotoxicity were investigated in human promyelocytic leukemia HL‐60 cells. Treatment of selenite or selenodigtutathione resulted in concentration‐dependent cytotoxicity, measured by lactate dehydrogenase leakage assay, and by tetrazolium salt reduction assay. Selenodiglutathione has been shown to exert more cytotoxic effect than selenite in both assay systems. Time‐course study of cellular selenium uptake suggests that the higher cytotoxicity of selenodiglutathione be largely due to faster and greater selenium uptake rate. Treatment with selenite or selenodiglutathione also induced apoptosis in a dose‐dependent manner, as detected by enzyme‐linked immunosorbent assay and by DNA fragmentation assay. The dose‐response data of apoptosis induced by selenite or selenodiglutathione were similar to those of cytotoxicity, implicating a relationship between the induction of apoptosis and cytotoxicity. Zn, which is a well‐known inhibitor of apoptosis, dose‐dependently blocked not only the induction of apoptosis, but also the membrane damage induced by selenium, corroborating this hypothesis. It was noted that the inhibition of apoptosis by Zn exerted little protective effect on cytotoxicity at higher concentrations of selenium, compared with a perfect protective effect at low concentration of selenium. These results suggest that cytotoxicity induced by selenium may be partially correlated with apoptosis.
Chemical modification studies on the glucose/mannose specific lectins from field and lablab beans
Authors: Nadimpalli Siva Kumar 
Published: July 2007

AbstractSeeds of Dolichos lablab var. lignosus (field beans) and variety typicus (lablab beans) contain glucose/mannose specific lectins that have been affinity purified and well characterised (Siva Kumar N., and Rajagopal Rao, D., J. Biosci., 1986, 10, 95‐109, (1) Rajasekhar etal., (Biochem.Archives. 1997, 13, 233‐240) (2). Purified lectins are glyeoproteins with a native molecular mass of 60 kDa and are made of two types of subunits (Gowda etal., 1994, J.Biol.Chem. 269, 18789‐18793) (3). Chemical modifications of various groups in purified lectins (using group specific reagents) such as lysine (citraeonie anhydride), carboxyl groups (water soluble earbodi‐imide) tyrosine (N‐acetyl imidazole) and tryptophan (2‐hydroxy 5‐nitro benzylbromide) revealed that 14 out of 21 residues of lysines 7 out of 92 residues of carboxyl groups, 16 out of 24 tyrosine residues and 2 out of 10 tryptophan residues were modified. Lysine and carboxyl group modification led to 95% loss in haemaglutinating activity compared to control while tyrosine and tryptophan modifications led to complete loss of lectin activity. Arginine and histidine modifications led to only 50% loss in activity. The extent of modification and loss in activity was same when the lysine and carboxyl groups were modified in the presence and absence of the inhibitory sugar methyl α‐D‐glucopyranoside at 0.1M concentration. However protection of modification and lectin activity was observed when the tyrosine and tryptophan residues were modified in the presence of the inhibitory sugar. Earlier CD studies carried out (1) and extensive chemical modification studies reported here substantiate the involvement of tyrosine and tryptophan residues in the sugar binding site of these lectins.
Changes in membrane‐bound leucine aminopeptidase activity during maturation and ageing of brain
Authors: Arechaga Garbiñe , Martínez José M. , Prieto Isabel , Ramírez María J. , Alba Fraucisco , Ramírez Manuel 
Published: July 2007

AbstractAminopeptidases are believed to be enzymes that regulate the activity of various neuropeptides. However, their physiological role, as well as their mechanisms of regulation, are not well understood. To analyze a part of the regulatory mechanisms that control the activity of these enzymes, the subcellular distribution of membrane‐bound leucyl aminopeptidase activity was studied in rat brain during development and ageing. Except in fetuses, the enzymic activity was greatest in the microsomal fraction in all ages tested. Except in microsomal and myelin fractions, compared with fetuses, leucyl aminopeptidase activity showed a decrease in 1‐week‐old rats and a subsequent increase to adult levels in 1‐month‐old rats. This profile differed in the microsomal fraction, where the activity increased steadily up to 1‐month‐old rats. After this age, the activity decreased progressively in 5‐month and 24‐month‐old rats. These results may reflect changes in the functional status of the susceptible substrates during development and ageing.
Regulation of an 8‐kDa peptide involved in testosterone production by luteinizing hormone in rat leydig cells
Authors: Ramaraj P. , Rao A. Jagannadha 
Published: July 2007

AbstractResults of Western blot analysis carried out with an interstitial cell extract from male guinea pig and ovarian extract from immature female rats administered equine chorionic gonadotropin (eCG) provide supportive evidence to our earlier suggestion that an 8‐kDa peptide is involved in acquisition of steroidogenic capacity by the rat Leydig cells. It was found that though the signal was observed in other tissues such as liver, kidney and lung which do not produce gonadal hormones, the peptide was modulated only by lutenizing hormone (LH) in the rat Leydig cells.
The involvement of hexokinases in trehalose synthesis
Authors: Peixoto Daniele N. , Panek Anita D. 
Published: July 2007

AbstractYeast cells harboring a MAL2‐8c gene accumulate trehalose during the transition phase of growth on glucose due to the presence of the ADPG‐dependent trehalose 6‐phosphate synthase. Under these conditions, glueokinase appeared not to provide G‐6‐P for trehalose synthesis and the two hexokinases seemed to act synergistically. After incubation in d‐xylose, trehalose levels in these cells dropped almost in 90%, confirming the involvement of both hexokinases in the accumulation of this carbohydrate. Nevertheless, G‐6‐P levels appeared to be similar in all strains. Some explanations for this paradox are discussed. In stationary phase, neither of the three isoenzymes were involved in trehalose synthesis. Possibly, gluconeogenesis provides the substrate for trehalose synthesis at that stage.
The lysine and methionine rich basic subunit of buckwheat grain legumin: Some results of a structural study
Authors: Rout M. K. , Chrungoo N. K. 
Published: July 2007

AbstractThe 26 kD basic subunit of 280 kD buckwheat grain legumin has been partially characterized by measurement of its fluorescence and CD spectra. The protein has 22% α‐helix, 36% β‐sheet, 12% β‐turn and 30% random coil secondary structure. In comparison with the basic subunits of other legumin‐type proteins, the buckwheat legumin subunit has a high content of lysine and methionine. The protein also has higher ratios of lysine to arginine and methionine to arginine.
Porphyria‐induced hepatic porphyrinogen carboxy‐lyase inhibitor and its interaction with the active site(s) of the enzyme
Authors: de Catabbi S. Billi , de Cahmanovici R. Wainstok , Minutolo C. , Aldonatti C. , de Viale L.C. San Martin 
Published: July 2007

AbstractPorphyrinogen carboxy‐lyase is an enzyme that sequentially decarboxylates uroporphyrinogen III (8‐COOH) to yield coproporphyrinogen III (4‐COOH). In mammals this enzyme activity is impaired by hexachlorobenzene treatment, through generation of an enzyme inhibitor. The interaction of porphyrinogen carboxy‐lyase inhibitor, extracted from the liver of hexachlorobenzene‐treated rats, with substrate decarboxylation sites on the enzyme, was studied using four different carboxylated substrates belonging to the isomeric III series of naturally‐formed porphyrinogens containing 8‐,7‐,6‐ and 5‐COOH.Similar inhibitor effects were elicited against all the substrates assayed, with the exception of pentacarboxyporphyrinogen III in which decarboxylation was not inhibited to same extent.Enzyme protection assays in the presence of the different substrates, indicated that each porphyrinogen protects its own decarboxylation from inhibitor action.Preincubation of the inhibitor with normal enzyme increased its inhibitory effect. On the other hand, preincubation of both enzyme and inhibitor with superoxide dismutase or mannitol, did not alter inhibitory activity. Preincubation of the inhibitor with a number of aminoacids showed that only arginine and its derivative Nα‐Benzoyl‐L‐Arginine ethyl ester interact with the inhibitor, noticeably reducing its ability to inhibit porphyrinogen carboxy‐lyase. Albumin, histidine, serine, cysteine and imidazol, were unable to quench inhibitor activity.The present results indicate that the inhibitor acts at the binding site of each porphyrinogen. Taking into account that arginine is related to enzyme activity, and that histidine is found at the binding site of the substrates, the results suggest that the inhibitor could bind to arginine residues, blocking the access of substrates to histidine and altering the adequate orientation for decarboxylation by masking the positively charged active site necessary for porphyrinogen binding to the enzyme. In addition an indirect effect of the inhibitor mediated through free radicals could be discarded.
cDNA Cloning of the Two Subunits of Phospholipase A2 Inhibitor PLIgamma from Blood Plasma of the Chinese Mamushi, Agkistrodon blomhoffii siniticus
Authors: Okumura Kohji , Inoue Seiji , Ohkura Naoki , Ikeda Kiyoshi , Hayashi Kyozo 
Published: July 2007

AbstractThree phospholipase A2 (PLA2) inhibitors (PLI) have been purified from the blood plasma of the Chinese mamushi, Agkistrodon blomhoffii siniticus; 1 of these, PLI gamma, contains 2 homologous subunits, PLI gamma‐A and PLI gamma‐B. The cDNAs encoding these 2 subunits of PLI gamma were isolated from a liver cDNA library by using fragments from polymerase chain reaction amplifications as probes and sequenced. The respective nucleotide sequences encoded 19‐residue signal sequences, followed by 181‐residue proteins. The calculated molecular masses were 20123 and 20150 Da for the PLI gamma‐A and PLI gamma‐B subunits, respectively; and PLI gamma‐A included a N‐linked carbohydrate site at Asn‐157. The sequences of these subunits contained 2 internal repeats of disulfide‐bonding pattern characteristic to those of urokinase‐type plasminogen activator receptor and members of the Ly‐6 superfamily. A phylogenetic analysis comparing the amino acid sequences of PLI gamma‐A and PLI gamma‐B with those for other snakes revealed that the gene duplication leading to these 2 subunits occurred before the divergence of Viperidae and Elapidae.
Identification of a Novel Cytosolic Tocopherol‐Binding Protein: Structure, Specificity, and Tissue Distribution
Authors: Stocker Achim , Zimmer Sabine , Spycher Stefan E. , Azzi Angelo 
Published: July 2007

Abstractalpha‐Tocopherol plays an important role as a lipid‐soluble antioxidant. It is present in all major mammalian cell types and shows tissue‐specific distribution. This suggests the presence of specific proteins involved in intracellular distribution or metabolism of alpha‐tocopherol. A diminution of tocopherol plasma concentrations contributes to the development of diseases such as vitamin E deficiency (AVED), atherosclerosis, and prostate cancer. Further evidence has been obtained for the existence of sites in cellular metabolism and signal transduction where alpha‐tocopherol potentially plays a regulatory role. A signal transduction modulation specific for alpha‐tocopherol has been described in several model systems. Using radioactively labeled alpha‐tocopherol as tracer, we have isolated a new alpha‐tocopherol‐associated protein (TAP) from bovine liver. This protein has a molecular mass of 46 kDa and an isoelectric point of 8.1. From its partial amino acid sequence, a human gene has been identified with high homology to the newly described protein. Sequence analysis has established that the new TAP has structural motifs suggesting its belonging to a family of hydrophobic ligand‐binding proteins (RALBP, CRALBP,alpha‐TTP, SEC 14, PTN 9, RSEC 45). Human TAP has been cloned into Escherichia coli, and its tissue‐specific expression has been assessed by Northern blot analysis.
Rate of 14CO2 Production from Variously Labeled Forms of [14C]Glucose in Human Breast Invasive Ductal Carcinoma Tissues
Authors: Yan Shou He , Wallon Joelle , Mayaudon Jacques 
Published: July 2007

AbstractTo establish possible cancerous aggressiveness between the metabolism of variously labeled [14C]glucose in the human breast invasive ductal carcinoma (IDC) tissues, we measured the rates of 14CO2 production from those tissues by using radiorespirometry, expressing the results as initial velocity (V) in nanomoles of 14CO2 min‐1 g‐1 of fresh tissues. The Vc data were compared with results of the SBR system, which grades up from I to III. Vc,1 values measured with [1‐14C]glucose increased from 1.99‐2.82 for SBR I to 3.90‐4.09 for SBR II, finally reaching 4.83‐7.04 for SBR III, thus matching clearly the increase of IDC cancerous aggressiveness. Conversely, data obtained from [3,4‐14C]glucose and [6‐14C]glucose decreased with increasing cancer stage: i.e., with [3,4‐14C]glucose, Vc,3,4 values were 5.79‐9.34 for SBR I, 4.45‐4.84 for SBR II, and 2.35‐1.90 for SBR III; with [6‐14C]glucose, the corresponding Vc,6 values were 1.34‐1.90, 1.33‐1.41, and 0.72‐0.79. The Vn,1/Vn,6 ratios were close to unity for normal tissues and for noncancerous tissues surrounding SBRI tumors. For cancerous tissues, however, the Vc,1/Vc,6 ratios were 1.5, 2.9, and 6.1‐9.8 in IDC tissues graded as SBR I, II, and III, respectively. The results suggest the possible use of radiorespirometry as a tool to assess IDC aggressiveness.
Organizational Complexity of a Rice Transgene Locus Susceptible to Methylation‐Based Silencing
Authors: Kumpatla Siva P. , Hall Timothy C. 
Published: July 2007

AbstractMolecular analyses of a rice (Oryza sativa L.) transgene locus introduced using biolistic techniques revealed the presence of multiple copies of rearranged fragments, as well as an intact copy of the supplied constructs. Both the gene of interest (35S‐Btt cryIIIA) and the selectable marker used (Ubi1‐bar) were methylated and silenced. Additionally, vector sequences were present in great abundance and were also highly methylated, indicating that the entire transgene insert was marked for methylation. The rearrangement of input DNA resulted in interspersion of plasmid backbone regions with the gene of interest. Permutation of segments encoding the gene of interest and the selectable marker was also detected, perhaps explaining why sequences introduced on separate plasmids are frequently found to be inserted at the same locus. The 35S promoter contained several hotspots for fragmentation. These observations strongly support the concept that intrusive DNA is recognized by host surveillance systems and that transgene loci with anomalous structural organization are subjected to inactivation by processes such as methylation.