bluuebunny/crossref_metadata_2025_split huggingface dataset:
Identification of histidine residues in the sugar binding site of snake gourd (Trichosanthes anguina) seed lectin
Authors: Komath Sneha Sudha , Nadimpalli Siva Kumar , Swamy Musti J. 
Published: July 2007

AbstractChemical modification studies have been carried out on the galactose‐specific lectin (SGSL) purified from snake gourd (Trichosanthes anguina) seeds. Modification of the imidazole side chains of histidine residues with ethoxyformic anhydride resulted in a complete loss of activity of the lectin. A total of 9.5 (±0.7) histidine residues were modified per dimer of Mr 55,000 when the reaction was carried out for 2 hours. A partial protection was observed when the modification was done in the presence of 0.1M galactose, indicating that histidine residues are directly involved in the sugar‐binding activity of the lectin. Complete recovery of the lectin activity was observed when the modification was reversed by treatment with hydroxylamine. In immunodiffusion experiments, the histidine‐modified lectin reacted with rabbit antiserum raised against the native SGSL forming a precipitin line, indicating that the loss of activity upon modification was not due to changes in the overall conformation of the lectin. Modification of the side chains of lysine, cysteine and tyrosine residues did not result in any change in the activity of SGSL.
Angiotensin II and related peptides alter liposomal membrane fluidity
Authors: Brailoiu Eugen , Margineanu Anca , Miyamoto Michael D. 
Published: July 2007

AbstractWe investigated the effects of angiotensinogen (Ang), angiotensin I (Ang I), and angiotensin II (Ang II) on the fluidity of phosphatidylcholine vesicles. Changes in fluidity were assessed by changes in anisotopy values calculated from fluorescence polarization measurements. All three compounds produced an increase in membrane fluidity when localized inside the phosphatidylcholine vesicles. When placed outside the vesicles, Ang II increased bilayer rigidity (decreased fluidity), whereas Ang and Ang I produced no effect. These results suggest the possibility that these peptides may alter the fluidity of cell membranes by a direct action on the phospholipid bilayer, which may in turn interfere with receptor‐mediated effects.
Inductions of immediate early genes (IEGs) and ref‐1 by human chorionic gonadotropin in murine Leydig cell line (MA‐10)
Authors: Suzuki Syoji , Nagaya Takashi , Suganuma Nobuhiko , Tomoda Yutaka , Seo Hisao 
Published: July 2007

AbstractThe effect of human chorionic gonadotropin (hCG) on the expression of immediate early genes (IEGs) including all members of fos and jun family, and c‐myc was studied using mouse Leydig cell line (MA‐10 cells) by Northern blot analyses. In addition, the induction of ref‐1 which enhances DNA binding of fos/jun proteins was also analyzed. HCG induced a rapid and transient expression of c‐fos, fosB, c‐jun, junB, junD and c‐myc with a peak at 30 min to 1h. In contrast, induction of fra‐1 mRNA was delayed with a peak at 3 hr. However, fra‐2 mRNA was immediately increased by hCG with a peak at 1 h. The ref‐1 mRNA was expressed before the stimulation and its level was not altered by hCG at least for 8 hr. The differential induction of IEGs and continuous expression of ref‐1 mRNA suggest an important role of their gene products on the regulation of Leydig cell function by hCG.
Protein kinase C from rainbow trout brain: Identification and characterization of three isozymes
Authors: Brooks S. P. J. , Storey K. B. 
Published: July 2007

AbstractFree and membrane‐associated fractions of protein kinase C (PKC) from rainbow trout (Onchorynchus mykiss) brain tissue were separated by hydroxylapatite chromatography and characterized kinetically. In both resting fish and in fish swum to exhaustion, approximately 40% of the total PKC activity was bound to membranes. Quantification of the three distinct hydroxylapatite chromatography peaks (PKC types γ, β and α) in cytosolic and membrane fractions revealed different isozyme distributions. The cytosolic fraction contained 21% PKC type γ, 52% PKC type β and 27% PKC type α. The membrane‐associated fraction contained 23% PKC type γ, 28% PKC type β and 49% PKC type α. Kinetic characterization of the three isozymes showed that PKC type γ was almost completely activated by Ca2+ alone whereas PKC type β and PKC type α were 40% and 60% activated by Ca2+. Full activity for all enzymes was observed only in the presence of phosphatidylserine and diacylglycerol. Differences in the kinetic constants for the three isozymes were also apparent. PKC type γ, had a much lower affinity for Histone III‐S when compared with PKC types β and α (100 μg/ml as compared with 1.7 and 5.7 μg/ml). PKC type γ, also had a lower affinity for calcium (0.22 μM) when compared with PKC type β (0.08 μM) and PKC type α (0.05 μM). PKC type α had a lower affinity for phosphatidylserine (8.6 μg/ml) when compared with PKC type γ (0.37 μg/ml) and PKC type β (0.89 μg/ml).
Electrostatic inhibition of hemolysis induced by organotin compounds
Authors: Kleszczynska H. , Pruchnik H. , Przestalski S. 
Published: July 2007

AbstractThe effect of cations on the kinetics of hemolysis caused by organotin compounds was studied. The ions used in the investigation diminish or totally inhibit hemolysis of red cells induced by organotin compounds. The degree of inhibition depends both on the kind of ion and the compounds that induce hemolysis. The ions Zn2+, Co2+, and Cd2+ present in the medium at 50 μM concentration totally protect the erythrocytes against hemolysis induced by the compound (C3H7)3SnCl. The study has also shown the monovalent ions K+ and trimethyldodecylammonium bromide are less potent inhibitors of hemolysis than divalent ions, which is not the case for two non‐ionic organotin compounds only. The studies performed indicate that hemolysis induced by organotin compounds is inhibited due to electrostatic interaction between the cations selected and erythrocyte membrane.
Differential expression of multidrug resistance (mdr) and canalicular multispecific organic anion transporter (cMOAT) genes following extrahepatic biliary obstruction in rats
Authors: Kagawa Tatehiro , Watanabe Norihito , Sato Masahiro , Nakano Atsushi , Nishizaki Yasuhiro , Hosoi Katsumi , Takashimizu Shinji , Uchiyama Junzo , Kimura Minoru , Matsuzaki Shohei 
Published: July 2007

AbstractThe hepatic canalicular membrane has transporters that play an important role as efflux pumps in the excretion of endogenous bile constituents or xenobiotics into bile canaliculi. To elucidate functional significance of canalicular transporters in the mechanism of cholestasis, mRNA expression levels of multidrug resistance (mdr) lb, mdr2 and canalicular multispecific organic anion transporter (cMOAT) genes were analyzed by Southern blotting of reverse‐transcribed PCR products of liver mRNA obtained from cholestatic rats that had been subjected to bile duct ligation. Both mdr1b and mdr2 mRNA expression increased after ligation. Immunohistochemical study revealed that the products of both mdr1b and mdr2 were present on the canaliculi, and that their levels increased after ligation. In contrast, cMOAT mRNA expression was not increased, but rather attenuated by ligation. The expression of canalicular transporters was differentially regulated in extrahepatic biliary obstruction, indicating the different roles are played by mdr and cMOAT in the pathogenesis of cholestasis.
A sequence highly similar to PNG is located on chromosome 22q12 in intron 15 of the LIMK‐2 gene
Authors: Carson Darek Kedra Emma , Weber Günther , Lagercrantz Jacob 
Published: July 2007

AbstractIn this report we describe a sequence (PNG22) highly similar to the Phospholipase C β3 Neighboring Gene (PNG). We also report that PNG22 is located in the q12 region on chromosome 22 between markers D22S1144 and D22S280. This finding explains that PNG probes cross hybridize to sequences on chromosome 22. Fine mapping using our sequence data and the complete sequence of a PAC clone (DJ515N1), located in this region, determined that PNG22 is located in intron 15 of the LIMK‐2 gene. PNG22 is 93% homologous to PNG, however it do not have the introns described for the PNG gene, instead matching the cDNA sequence. This leads us to suggest that PNG22 probably represents a PNG pseudogene. In this report we also list the exon intron borders and the genomic structure of LIMK‐2 and place it on the Sanger Center chromosome 22 Physical map. It also explains the finding that PNG probes cross hybridize to sequences on chromosome 22.
Protective role of superoxide dismutase in iron toxicity in yeast
Authors: Wisnicka Renata , Krzepiłko Anna , Wawryn Jarosław , Krawiec Zdzisława , Bilinski Tomasz 
Published: July 2007

AbstractIt has been found that yeast mutants deficient in cytosolic superoxide dismutase CuZnSOD are hypersensitive to ferrous iron. In contrast mutants that are deficient in catalases and cytochrome c peroxidase do not differ from the standard strain in this respect. These findings suggest that iron toxicity may depend on the redox status of the cell. They also shed light on the role of superoxide dismutases in preventing the toxic effects of oxygen.
Identification of an enhancer sequence in 5′‐flanking region of 1A exon of mouse liver/bone/kidney‐type alkaline phosphatase gene
Authors: Kobayashi Tatsuya , Sugimoto Toshitsugu , Kanzawa Michiko , Chihara Kazuo 
Published: July 2007

AbstractThe 5′‐flanking region of the 1A exon of the mouse liver/bone/kidney‐type alkaline phosphatase (L/B/K (ALP) gene was analyzed for the promoter activity. Luciferase assays revealed that a segment containing a 9 bp inverted repeat (nt‐1212 to ‐1179, designated as IRS for inverted repeat segment) had an enhancer activity. Though an E‐box at nt ‐234 did not have a prominent promoter activity, the effect of IRS required its presence. Both transcriptional activity and IRS binding to the nuclear proteins were similarly observed even in cells that did not express ALP. Bone morphogenetic protein‐2 (BMP‐2) induced the ALP expression in pluripotent C3H10T1/2 cells, but it did not increase the transcriptional activity of the promoter region. Though they do not determine cell specific or BMP‐2 inducible ALP expression, IRS and the E‐box at position ‐241 seem to be important for the basic transcriptional activity of ALP gene.
Subunit structure of lysine sensitive aspartate kinase from spinach leaves
Authors: Kochhar S. , Kochhar V. K. , Sane P. V. 
Published: July 2007

AbstractThe lysine‐sensitive isoenzyme of aspartate kinase was purified to homogeneity from spinach leaves and its subunit composition was studied. The purified preparation had an apparent molecular mass of 280,000 and separated into two subunits‐ a large subunit with molecular mass of 53000 and smaller subunit with molecular mass of 17,000 by urea treatment and SDS PAGE. The enzyme molecule has subunit composition of 4 large and 4 small subunits. The activity of the large subunit was stimulated more than two fold by the addition of small subunit and the stimulated activity was inhibited by EGTA. This inhibition could be reversed by Ca++. Further characteristics of the smaller subunit such as heat stability, behavior on ion exchange chromatography, elctrophoretic mobility on polyacrylamide gels, amino acid composition and pattern, presence of trimethyl lysine, its ability to activate other calmodulin stimulated enzymes and its calmodulin‐like nature in RIA tests suggested that this subunit is identical to calmodulin.
p116 transcript predicting an alternative form of sulfated glycoprotein‐2 (clusterin) is transcribed by alternative splicing mechanism
Authors: Izawa Masao 
Published: July 2007

AbstractTo further determine the role of androgens in the seminal vesicle physiology, we previously undertook cDNA cloning of androgen‐responsive mRNAs from rat seminal vesicles, and isolated several cDNA clones. During the process of characterization, we have isolated a distinct cDNA clone designated p116, predicting the expression of a transcript encoding an alternative form of sulfated glycoprotein‐2 (SGP‐2, clusterin). In the present study, we addressed the question of whether SGP‐2 and p116 transcripts are transcribed from an identical gene by alternative splicing mechanism or not. Results from genomic PCR and genomic Southern analyses demonstrate that p116 and SGP‐2 mRNAs are transcribed from their respective exons of an identical gene. Since the expression of SGP‐2 has been proposed as a molecular marker of apoptosis, it is important to further understand the roles of expressions of SGP‐2 and its related p 116 proteins in apoptotic cells.
Quantitative measurement of protein S gene expression by reverse transcription‐competitive PCR method; determination of mRNA level in fractionated human peripheral blood cells and various cultured cell lines
Authors: Okamoto Yoshihiro , Hara Yusuke , Ishikawa Satomi , Nishida Mikio 
Published: July 2007

AbstractWe developed the measurement system for human protein S mRNA (cDNA) by a reverse transcription‐competitive polymerase chain reaction (RT‐competitive PCR) method with a compact digital camera. The sensitivity of the method was 100,000 fold more sensitive than the traditional northern blot analysis. We confirmed the accuracy and usefulness of the system by measuring the absolute values of protein S mRNA in fractionated peripheral blood cells, namely platelets, mononuclear cells, granulocytes and red blood cell from healthy human and six different cultured disease cell lines tested, namely, lung carcinoma, stomach carcinoma, hepatoma, highly differentiated hepatoma, promyelocytic leukemia and monocytic leukemia. The amount of protein S mRNA in the platelet rich fraction (6.89×10‐19 mol/μg total RNA) was the largest of all fractions tested and that in the mononuclear cells was the second largest. In the fractions of granulocytes and red blood cells, no protein S mRNA was detected. The detected values in five cell lines ranged from approximately 5.6×10‐19 to 97.2×10‐19 mol/μg total RNA. The content was reduced in the order, highly differentiated hepatoma>hepatoma>lung carcinoma>stomach carcinoma>monocytic leukemia. Promyelocytic leukemia cell line had no expressed protein S mRNA. Thus, the assay system described here was sensitive, reproducible, simple and useful for the quantitative measurement of an infinitesimal level of protein S mRNA to characterize normal and/or patho‐physiological states of human blood and somatic cells.
The synthesis of HSPs in sugar beet suspension culture cells under hyperthermia exhibits differential sensitivity to calcium
Authors: Kuznetsov Vladimir V. , Andreev Igor M. , Trofimova Marina S. 
Published: July 2007

AbstractExperiments aimed at testing the effect of Ca2+ on heat shock‐induced changes in protein synthesis of cultured sugar beet cells were performed. Heat shock inhibits the synthesis of non‐heat shock proteins (non‐HSPs) and promotes the synthesis of a set of HSPs. Extracellular Ca2+ appeared to be strictly required for the synthesis of non‐HSPs. Calcium was found to differentially exert its effect on the HSP synthesis: calcium induced (96 and 76 kDa), stimulated (94, 67, 58, 52, 32, 30, 26 and 22 kDa) or did not influence (82, 17 kDa) the de novo production of various HSPs. Cell injury increased if the cells were exposed to high temperature in a Ca2+‐deficient medium. Calcium supplement to Ca2+‐depleted cells resulted in the recovery of HSP synthesis and reduced cell injury by heat shock.
Pigment organization and exciton dynamics in the B808‐866 antenna of the green bacterium Chloroflexus aurantiacus
Authors: Novoderezhkin Vladimir , Taisova Alexandra , Fetisova Zoya 
Published: July 2007

AbstractThe model for the B808‐866 antenna of the green photosynthetic bacterium Chloroflexus aurantiacus based on femtosecond pump‐probe studies is proposed. The three‐dimensional structure of the B808‐866 antenna is assumed to be similar to the structure of the B800‐850 antenna of purple bacteria, i.e. it has the form of two concentric rings of N strongly coupled BChl866 pigments and of N/2 weakly coupled BChl808 monomers. The Qy transition dipoles of BChl808 and BChl866 molecules form the angles 43°±3° and 8°±4°, respectively, with the plane of the corresponding rings. The lowest limit of the BChl866 aggregate size is N=18. The anomalously high bleaching value of the BChl866 band with respect to the monomeric BChlS08 band provides evidence for a high degree of exciton delocalization. To account for this phenomenon, the exciton model describing exciton dynamics in the spectrally disordered circular BChl866 aggregate is developed. According to this model, the effective exciton size in this antenna (Neff) is 6‐8.
Analysis of 66 kDa toxin from Bacillus thuringiensis subsp, kurstaki reveals differential amino terminal processing of protoxin by endogenous protease(s)
Authors: Kumar N. Suresh , Venkateswerlu G. 
Published: July 2007

AbstractThe endogenous protease(s) activated crystal toxin from Bacillus thuringiensis subsp, kurstaki was purified and examined. The purified toxin was homogenous, as demonstrated by two‐dimensional polyacrylamide gel electrophoresis and contained 1.38 μmoles neutral sugar and 9 nmoles sialic acid per mg protein, amino terminal amino acid sequence data revealed that the toxin is a cleavage product of 132 kDa protoxin with glutamic acid‐30 of the deduced amino acid sequence of the crystal protein (Schnepf, H.E., Wong,HC and Whiteley,H.R. (1985) J. Biol. Chem. 260: 6264‐6272) at the amino terminus.
Influence of some quanternised 1,4‐Dihydropyridine derivatives on liposomes and erythrocyte membranes
Authors: Tirzite D. , Koronova J. , Plotniece A. 
Published: July 2007

Abstract1,4‐Dihydropyridine derivatives possess various physiological activities but their mechanism of membranotropic action is not completely investigated yet. We have examined the membranotropic effects of 4‐β‐pyridyl‐1,4‐dihydropyridine derivatives containing different length alkyl chain substituent at N‐quaternised 4‐β‐pyridyl moiety. The results show the relation between incorporation of 1,4‐dihydropyridine derivatives in the liposomal membranes and influence on bilayer fluidity. The compound with hexadecyl (C16H33) substituent in the 4‐β‐pyridyl moiety possess the most pronounced incorporation ability and fluidizing effect. This compound causes the remarkable release of fluorescent probe calcein from liposomes and induces the hemolysis of human erythrocytes as well. The obtained results suggest that the length of alkyl chain at quaternized 4‐β‐pyridyt moiety is significant for the expression of membranotropic effects of tested compounds.
Lower archidonic acid content and preferental β‐oxidation of arachidonic acid over palmitic acid in tumour cell lines as compared to normal lymphoid cells
Authors: Barbieri B. , Alvelius G. , Papadogiannakis N. 
Published: July 2007

AbstractIn several studies certain polyunsaturated fatty acids (PUFA) have been shown to be selectively tumouricidal or suppressive of tumour cell proliferation. The mechanism behind this phenomenon likely involves peroxidation of the PUFA and generation of free radicals to which tumour cells seem to be more sensitive than normal cells.In this report we have measured the total lipid content in separated lymphoid cells and several tumour cell lines, among which, T‐cell leukaemia, monocytic leukaemia, melanoma, fibrosarcoma, lung carcinoma and colon adenocarcinoma are included. Generally these tumour cell lines contain only one half to one third of the relative amount of arachidonic acid (AA) as compared to fleshly prepared lymphocytes and monocytes or lymphocytes kept in culture.Furthermore, when we measured the β‐oxidation in long term incubation of [1‐14C] AA and compared it with that of [1‐14C] palmitic acid we found that several of the tumour cell lines showed a preference for AA over palmitic acid in the tumour cell lines whereas the opposite was observed for normal lymphoid cells.
Modulation of map kinase signaling and growth characteristics by the overexpression of protein kinase C in NIH3T3 cells
Authors: Chang Yoon‐Young , Kim Soo‐Jung , Park Tae‐Kyu , Kang Shin‐Sung , Ha Mahn Joon , Mushinski J. Fredric , Chun Jang‐Soo 
Published: July 2007

AbstractThis study was performed to examine effects of the overexpression of protein kinase C (PKC) isoforms (i.e., βI, βII, γ, δ,η, and ζ) mitogen‐activated protein (MAP) kinase (Erk‐1 and ‐2) signaling and growth characteristics of NIH3T3 cells. Phorbol ester (PMA) activated endogenous and ectopically expressed PKCα, βI, βII, γ, δ, ε, and η. Overexpression of the examined PKC isoforms enhanced PMA‐induced MAP kinase activation. Potentiation of MAP kinase activation was also observed upon stimulation of cells with platelet‐derived growth factor (PDGF) although there was no indication for the activation PKC isoforms by PDGF. Inhibition of PKC blocked PMA‐ but not PDGF‐induced MAP kinase activation. Thus, potentiation of PDGF‐induced MAP kinase activation appears to be independent to PKC activity, while PMA‐induced MAP kinase activation requires PKC activity. The ability of PKC isoforms to potentiate MAP kinase activation is not related to the growth characteristics of cells because individual PKC isoforms differentially regulated maximum density and proliferation of cells.
Glutathione metabolism and glutathione S‐conjugate export ATPase (MRP1/GS‐X pump) activity in cancer
Authors: de Bittencourt Paulo Homem , Senna Sueli M. , Vidor Ana C. , Miyasaka Célio K. , Curi Rui , Williams John F. 
Published: July 2007

AbstractA severe complication in late‐stage cancer patients is host immunosuppression. It is suggested that overproduction of the highly cytostatic and cytotoxic antiproliferative cyclopentenone prostaglandins (CP‐PGs) within the plasma of cancer‐bearing subjects may contribute to immunosuppression. Lymphoid tissues of Walker 256 tumor‐bearing rats accumulate large amounts of CP‐PGs while the tumor tissue itself does not. Moreover, tumor cells may present differential sensitivity to CP‐PGs due to the expression of the multidrug resistance‐associated protein (MRP1) gene product which shows a Mg2+‐dependent vanadate‐sensitive glutathione S‐conjugate export ATPase (GS‐X pump) activity that extrudes CP‐PGs from cells as glutathione S‐conjugates. In this study, the possibility that deficient GS‐X pump activity in immune cells that may be involved in the accumulation of CP‐PGs is investigated. Rat lymph node lymphocytes do not exhibit any notable activity even when mitogen‐stimulated. Conversely, although rat peritoneal resident (quiescent) or thioglycollate‐stimulated (inflammatory) macrophages exhibit low GS‐X pump activity, Bacillus Calmette‐Guérin (BCG)‐activated macrophages show a notable rise in the activity of the ATPase, suggesting that the cellular activation state may modulate GS‐X pump activity/expression and that, under appropriate stimuli (e.g. during immune response) macrophages may provide a self‐defense against etectrophilic CP‐PGs by forming GS‐conjugates that can be extruded from cells through the GS‐X pump. ras oncogene expression may be linked with MRP1/GS‐X pump expression/activity, since C2C12 promyoblasts transformed by v‐H‐ras transfection doubled GS‐X pump activity. These results support the proposition that the accumulation of CP‐PGs and the immunosuppression of tumor‐bearing subjects may be attributed to a lack of GS‐X pump activity/expression in lymphocytes.