bluuebunny/crossref_metadata_2025_split huggingface dataset:
Channelling of substrate promiscuity of the skeletal-muscle ADP-ribosyl cyclase isoform
Authors: BACHER Ingrid , ZIDAR Andreas , KRATZEL Martin , HOHENEGGER Martin 
Published: June 2004

The novel Ca2+-mobilizing second messengers cADPr (cyclic ADP-ribose) and NAADP (nicotinic acid–adenine dinucleotide phosphate) are both synthesized by ADP-ribosyl cyclases. Using HSR (heavy sarcoplasmic reticulum) fractions from rabbit skeletal muscle, NAADP-induced Ca2+ release was observed. In the present paper, we show in HSR membranes the formation of authentic cADPr, cGDPr (cyclic GDP-ribose) and NAADP. The cyclization reaction to form cADPr and cGDPr as well as the base-exchange reaction to form NAADP were strictly dependent on pH. Although the formation of cGDPr is optimized at pH 6, the synthesis of NAADP was most pronounced at a pH below 5. A novel regulation mechanism is provided for nicotinic acid, the co-substrate for NAADP synthesis. Nicotinic acid had virtually no influence on the cyclization reaction, but increased the affinity of NADP at an acidic pH and had the opposite effect at alkaline pH. Nicotinamide, the side product of cADPr synthesis, is an inhibitor of the cyclization reaction (IC50, 0.7±0.1 mM) and was 30-fold more potent at suppressing the base-exchange reaction. Although the synthesis of NAADP was highly sensitive to nicotinamide inhibition, this was not via a competition with the nicotinic-acid-binding site. In contrast with the ecto-ADP-ribosyl cyclase (CD38), the cyclization and base-exchange reaction of the skeletal muscle isoform was inhibited by Cu2+ and Zn2+, while other bivalent cations such as Ca2+, Mg2+ and Mn2+ had virtually no effect. These findings allow for the prediction of a novel ADP-ribosyl cyclase isoform in skeletal muscle HSR, other than CD38. Hence the enzymic prerequisite for cADPr- and NAADP-mediated Ca2+ signalling is present.
The sulphur oxygenase reductase from Acidianus ambivalens is a multimeric protein containing a low-potential mononuclear non-haem iron centre
Authors: URICH Tim , BANDEIRAS Tiago M. , LEAL Sónia S. , RACHEL Reinhard , ALBRECHT Till , ZIMMERMANN Peter , SCHOLZ Corinna , TEIXEIRA Miguel , GOMES Cláudio M. , KLETZIN Arnulf 
Published: June 2004

The SOR (sulphur oxygenase reductase) is the initial enzyme in the sulphur-oxidation pathway of Acidianus ambivalens. Expression of the sor gene in Escherichia coli resulted in active, soluble SOR and in inclusion bodies from which active SOR could be refolded as long as ferric ions were present in the refolding solution. Wild-type, recombinant and refolded SOR possessed indistinguishable properties. Conformational stability studies showed that the apparent unfolding free energy in water is approx. 5 kcal·mol−1 (1 kcal=4.184 kJ), at pH 7. The analysis of the quaternary structures showed a ball-shaped assembly with a central hollow core probably consisting of 24 subunits in a 432 symmetry. The subunits form homodimers as the building blocks of the holoenzyme. Iron was found in the wild-type enzyme at a stoichiometry of one iron atom/subunit. EPR spectroscopy of the colourless SOR resulted in a single isotropic signal at g=4.3, characteristic of high-spin ferric iron. The signal disappeared upon reduction with dithionite or incubation with sulphur at elevated temperature. Thus both EPR and chemical analysis indicate the presence of a mononuclear iron centre, which has a reduction potential of −268 mV at pH 6.5. Protein database inspection identified four SOR protein homologues, but no other significant similarities. The spectroscopic data and the sequence comparison led to the proposal that the Acidianus ambivalens SOR typifies a new type of non-haem iron enzyme containing a mononuclear iron centre co-ordinated by carboxylate and/or histidine ligands.
Participation of the proteasomal lid subunit Rpn11 in mitochondrial morphology and function is mapped to a distinct C-terminal domain
Authors: RINALDI Teresa , PICK Elah , GAMBADORO Alessia , ZILLI Stefania , MAYTAL-KIVITY Vered , FRONTALI Laura , GLICKMAN Michael H. 
Published: June 2004

Substrates destined for degradation by the 26 S proteasome are labelled with polyubiquitin chains. Rpn11/Mpr1, situated in the lid subcomplex, partakes in the processing of these chains or in their removal from substrates bound to the proteasome. Rpn11 also plays a role in maintaining mitochondrial integrity, tubular structure and proper function. The recent finding that Rpn11 participates in proteasome-associated deubiquitination focuses interest on the MPN+ (Mpr1, Pad1, N-terminal)/JAMM (JAB1/MPN/Mov34) metalloprotease site in its N-terminal domain. However, Rpn11 damaged at its C-terminus (the mpr1-1 mutant) causes pleiotropic effects, including proteasome instability and mitochondrial morphology defects, resulting in both proteolysis and respiratory malfunctions. We find that overexpression of WT (wild-type) RPN8, encoding a paralogous subunit that does not contain the catalytic MPN+ motif, corrects proteasome conformations and rescues cell cycle phenotypes, but is unable to correct defects in the mitochondrial tubular system or respiratory malfunctions associated with the mpr1-1 mutation. Transforming mpr1-1 with various RPN8–RPN11 chimaeras or with other rpn11 mutants reveals that a WT C-terminal region of Rpn11 is necessary, and more surprisingly sufficient, to rescue the mpr1-1 mitochondrial phenotype. Interestingly, single-site mutants in the catalytic MPN+ motif at the N-terminus of Rpn11 lead to reduced proteasome-dependent deubiquitination connected with proteolysis defects. Nevertheless, these rpn11 mutants suppress the mitochondrial phenotypes associated with mpr1-1 by intragene complementation. Together, these results point to a unique role for the C-terminal region of Rpn11 in mitochondrial maintenance that may be independent of its role in proteasome-associated deubiquitination.
Hypochlorite and superoxide radicals can act synergistically to induce fragmentation of hyaluronan and chondroitin sulphates
Authors: REES Martin D. , HAWKINS Clare L. , DAVIES Michael J. 
Published: June 2004

Activated phagocytes release the haem enzyme MPO (myeloperoxidase) and also generate superoxide radicals (O2•−), and hence H2O2, via an oxidative burst. Reaction of MPO with H2O2 in the presence of chloride ions generates HOCl (the physiological mixture of hypochlorous acid and its anion present at pH 7.4). Exposure of glycosaminoglycans to a MPO–H2O2–Cl− system or reagent HOCl generates long-lived chloramides [R-NCl-C(O)-R′] derived from the glycosamine N-acetyl functions. Decomposition of these species by transition metal ions gives polymer-derived amidyl (nitrogen-centred) radicals [R-N•-C(O)-R′], polymer-derived carbon-centred radicals and site-specific strand scission. In the present study, we have shown that exposure of glycosaminoglycan chloramides to O2•− also promotes chloramide decomposition and glycosaminoglycan fragmentation. These processes are inhibited by superoxide dismutase, metal ion chelators and the metal ion-binding protein BSA, consistent with chloramide decomposition and polymer fragmentation occurring via O2•−-dependent one-electron reduction, possibly catalysed by trace metal ions. Polymer fragmentation induced by O2•− [generated by the superoxide thermal source 1, di-(4-carboxybenzyl)hyponitrite] was demonstrated to be entirely chloramide dependent as no fragmentation occurred with the native polymers or when the chloramides were quenched by prior treatment with methionine. EPR spin-trapping experiments using 5,5-dimethyl1-pyrroline-N-oxide and 2-methyl-2-nitrosopropane have provided evidence for both O2•− and polymer-derived carbon-centred radicals as intermediates. The results obtained are consistent with a mechanism involving one-electron reduction of the chloramides to yield polymer-derived amidyl radicals, which subsequently undergo intramolecular hydrogen atom abstraction reactions to give carbon-centred radicals. The latter undergo fragmentation reactions in a site-specific manner. This synergistic damage to glycosaminoglycans induced by HOCl and O2•− may be of significance at sites of inflammation where both oxidants are generated concurrently.
Functional and biochemical characterization of a recombinant Arabidopsis thaliana 3-deoxy-D-manno-octulosonate 8-phosphate synthase
Authors: WU Jing , PATEL Mayur A. , SUNDARAM Appavu K. , WOODARD Ronald W. 
Published: June 2004

An open reading frame, encoding for KDOPS (3-deoxy-D-manno-octulosonate 8-phosphate synthase), from Arabidopsis thaliana was cloned into a T7-driven expression vector. The protein was overexpressed in Escherichia coli and purified to homogeneity. Recombinant A. thaliana KDOPS, in solution, displays an apparent molecular mass of 76 kDa and a subunit molecular mass of 31.519 kDa. Unlike previously studied bacterial KDOPSs, which are tetrameric, A. thaliana KDOPS appears to be a dimer in solution. The optimum temperature of the enzyme is 65 °C and the optimum pH is 7.5, with a broad peak between pH 6.5 and 9.5 showing 90% of maximum activity. The enzyme cannot be inactivated by EDTA or dipicolinic acid treatment, nor it can be activated by a series of bivalent metal ions, suggesting that it is a non-metallo-enzyme, as opposed to the initial prediction that it would be a metallo-enzyme. Kinetic studies showed that the enzyme follows a sequential mechanism with Km=3.6 μM for phosphoenolpyruvate and 3.8 μM for D-arabinose 5-phosphate and kcat=5.9 s−1 at 37 °C. On the basis of the characterization of A. thaliana KDOPS and phylogenetic analysis, plant KDOPSs may represent a new, distinct class of KDOPSs.
Murine cystathionine γ-lyase: complete cDNA and genomic sequences, promoter activity, tissue distribution and developmental expression
Authors: ISHII Isao , AKAHOSHI Noriyuki , YU Xiao-Nian , KOBAYASHI Yuriko , NAMEKATA Kazuhiko , KOMAKI Gen , KIMURA Hideo 
Published: June 2004

Cystathionine γ-lyase (CSE) is the last key enzyme in the trans-sulphuration pathway for biosynthesis of cysteine from methionine. Cysteine could be provided through diet; however, CSE has been shown to be important for the adequate supply of cysteine to synthesize glutathione, a major intracellular antioxidant. With a view to determining physiological roles of CSE in mice, we report the sequence of a complete mouse CSE cDNA along with its associated genomic structure, generation of specific polyclonal antibodies, and the tissue distribution and developmental expression patterns of CSE in mice. A 1.8 kb full-length cDNA containing an open reading frame of 1197 bp, which encodes a 43.6 kDa protein, was isolated from adult mouse kidney. A 35 kb mouse genomic fragment was obtained by λ genomic library screening. It contained promoter regions, 12 exons, ranging in size from 53 to 579 bp, spanning over 30 kb, and exon/intron boundaries that were conserved with rat and human CSE. The GC-rich core promoter contained canonical TATA and CAAT motifs, and several transcription factor-binding consensus sequences. The CSE transcript, protein and enzymic activity were detected in liver, kidney, and, at much lower levels, in small intestine and stomach of both rats and mice. In developing mouse liver and kidney, the expression levels of CSE protein and activity gradually increased with age until reaching their peak value at 3 weeks of age, following which the expression levels in liver remained constant, whereas those in kidney decreased significantly. Immunohistochemical analyses revealed predominant CSE expression in hepatocytes and kidney cortical tubuli. These results suggest important physiological roles for CSE in mice.
Progress in allogeneic bone marrow and peripheral blood stem cell transplantation for multiple myeloma: a comparison between transplants performed 1983–93 and 1994–98 at European Group for Blood and Marrow Transplantation centres
Authors: Gahrton G. , Svensson H. , Cavo M. , Apperley J. , Bacigalupo A. , Björkstrand B. , Bladé J. , Cornelissen J. , De Laurenzi A. , Facon T. , Ljungman P. , Michallet M. , Niederwieser D. , Powles R. , Reiffers J. , Russell N. H. , Samson D. , Schaefer U. W. , Schattenberg A. , Tura S. , Verdonck L. F. , Vernant J. P. , Willemze R. , Volin for the European Group for Blood L. ,   Marrow Transplantation (EBMT)
Published: June 2004

Out of 690 allogeneic matched sibling donor transplants for multiple myeloma reported to the European Group for Blood and Marrow Transplantation (EBMT) registry, 334 were performed during the period 1983–93 (all with bone marrow) and 356 during 1994–98 [223 with bone marrow and 133 with peripheral blood stem cells (PBSCs)]. The median overall survival was 10 months for patients transplanted during the earlier time period and 50 months for patients transplanted with bone marrow during the later period. The use of PBSCs was associated with earlier engraftment but no significant survival benefit compared to bone marrow transplants during the same time period. The improvement in survival since 1994 was the result of a significant reduction in transplant‐related mortality, which was 38%, 21% and 25% at 6 months and 46%, 30% and 37% at 2 years during the earlier period, and the later period with bone marrow and PBSCs respectively. Reasons for the reduced transplant‐related mortality appeared to be fewer deaths owing to bacterial and fungal infections and interstitial pneumonitis, in turn a result of earlier transplantation and less prior chemotherapy. Better supportive treatment and more frequent use of cytokines may also play a role. The improvement in survival was not directly related to the increased use of PBSCs.
Alpha‐Glucosylrutin: ein hochwirksames Flavonoid zum Schutz vor oxidativem Streß
Authors: Wolber Rainer , Stäb Franz , Max Heiner , Wehmeyer Annegret , Hadshiew Ina , Wenck Horst , Rippke Frank , Wittern Klaus‐Peter 
Published: June 2004

ZusammenfassungDas Bioflavonoid alpha‐Glucosylrutin (AGR) findet aufgrund seiner starken antioxidativen Wirksamkeit und hohen epidermalen Bioverfügbarkeit zunehmend Verwendung im dermato‐kosmetischen Bereich. Bioflavonoide sind sekundäre Pflanzenstoffe (Phytamine) mit einer gemeinsamen chemischen Grundstruktur und einem breit gefächerten Wirkungsspektrum, vor allem aber der Fähigkeit, reaktive Sauerstoffspezies (reactive oxygen species, ROS) zu neutralisieren. ROS beeinflussen und schädigen die Zelle sowohl durch direkte zytotoxische Effekte (Membrandestruktion durch Induktion radikalischer Kettenreaktionen, Mutationen nukleärer und mitochondrialer DNA etc.) als auch indirekt durch Modifikation intrazellulärer Signaltransduktionskaskaden, die entzündliche und proliferative Prozesse regulieren. Die ausgezeichnete antioxidative Wirksamkeit von AGR konnte durch verschiedene experimentelle in‐vitro‐ und in‐vivo‐Untersuchungen bestätigt werden. Weiterführende klinische Studien belegen eindeutig die Wirksamkeit einer prophylaktischen Anwendung von AGR bei dermatologischen Krankheitsbildern wie der polymorphen Lichtdermatose (PLD), bei denen oxidativer Streß von pathogenetischer Relevanz ist. Auch in anderen dermato‐kosmetischen Indikationsbereichen wie der vorzeitigen (lichtbedingten) Hautalterung scheint eine vorbeugende Behandlung mit AGR vielversprechend zu sein. In allen durchgeführten in‐vivo‐Untersuchungen zeigte sich zudem, daß AGR in den verwendeten Konzentrationen ein sehr gut hautverträglicher Wirkstoff für die medizinische Hautpflege ist.
FILTRATION AND REABSORPTION OF PROTEIN BY THE KIDNEY
Authors: Sellers Alvin L. , Griggs Neilyn , Marmorston Jessie , Goodman Howard C. 
Published: June 2004

Plasma proteins of the rat have been labelled by the in vivo injection of the dye T-1824.
From a study of the rate of disappearance of T-1824 from the circulating blood, and the total T-1824 content of the perfused kidney the rate of protein reabsorption from the glomerular fluid by the cells of the renal tubule has been calculated.
It is concluded that protein reabsorption by the cells lining the proximal convoluted tubule of the rat kidney proceeds at a rate of at least 5 mg. per hour, equivalent to a daily filtration and reabsorption of 33 per cent of the circulating plasma protein.
THE BINDING OF PENICILLIN IN RELATION TO ITS CYTOTOXIC ACTION
Authors: Eagle Harry 
Published: June 2004

1. In a previous study, the differing sensitivity of bacterial strains as they occur in nature appeared to be correlated with their correspondingly differing reactivity with penicillin. Presumably, the over-all reactivity of the cell with penicillin paralleled that of the vulnerable cell component(s). However, when penicillin-resistant variants of these strains (Streptococcus pyogenes, Micrococcus pyogenes, Diplococcus pneumoniae, and Streptococcus faecalis) were produced by serial passage through increasing concentrations of antibiotic, this correlation between resistance and the ability of the cell to bind penicillin was no longer apparent. Some resistant variants bound more penicillin than the parent, sensitive cell (Streptococcus faecalis, Micrococcus pyogenes), some were unchanged in their reactivity (Diplococcus pneumoniae, Micrococcus pyogenes), and some bound less (Streptococcus pyogenes, Micrococcus pyogenes). One resistant variant of Micrococcus pyogenes at first showed enhanced reactivity with penicillin; on continued passage through antibiotic, there was a further increase in resistance, but now associated with a significantly decreased reactivity. In the case of Diplococcus pneumoniae, a resistant variant at first reacted normally with penicillin; on continued passage in antibiotic, its binding affinity for penicillin gradually decreased, but with no associated further increase in resistance.
2. The reactivity with penicillin of cell-free sonic extracts of the resistant variants paralleled that of the intact organisms. Permeability considerations therefore did not seem involved in the increased resistance produced by serial passage in antibiotic.
3. The penicillin-resistant variants did not have an enhanced capacity to degrade the free intracellular antibiotic.
4. Possible alternative explanations are discussed in the text.
VITAMIN D AND ENDOCHONDRAL OSSIFICATION IN THE RAT AS INDICATED BY THE USE OF SULFUR-35 AND PHOSPHORUS-32
Authors: Dziewiatkowski Dominic D. 
Published: June 2004

The concentration of inorganic sulfate-sulfur in the serum of vitamin D-deficient rats, 2.6 to 3.5 mg. per cent, was found to be higher than that in the serum of normal rats of the same age, 2.0 mg. per cent. No change was observed following the administration of 25 γ of vitamin D2.
In accord with the results of others, it was found that a definitely increased deposition of phosphorus in femurs and tibiae had occurred 36 to 48 hours after the administration of vitamin D2 to vitamin D-deficient rats. An immediate increase in the uptake of sulfate by the skeleton was found using sodium sulfate-S35.
As measured by the specific activity of sulfate-sulfur in samples of chondroitin sulfate isolated from the skeletons of the vitamin D-deficient animals and from normal controls receiving equal doses of sulfur-35, the rate of synthesis of chondroitin sulfate in rachitic rats is similar to the rate in normal rats of the same age. Likewise, the incorporation of labelled sulfate into the sulfomuco-polysaccharides of the pelts was found to be equal at 12 hours to that in normal rats. Following the administration of vitamin D2 to deficient animals an increase in the rate of synthesis of the chondroitin sulfate of the skeletons was noted.
The radiochemical and radioautographic evidence suggest that there is in vitamin D-deficient rats an impaired utilization of chondroitin sulfate and that vitamin D2 is able to accelerate this process.
STUDIES ON HOST-VIRUS INTERACTIONS IN THE CHICK EMBRYO-INFLUENZA VIRUS SYSTEM
Authors: Finter Norman B. , Liu Oscar C. , Lieberman Melvin , Henle Werner 
Published: June 2004

The usefulness of the deembryonation technic has been analyzed as a tool in the study of various problems in the growth cycle of influenza virus in the entodermal cells of the allantoic of chick embryos.
Various improvements in the deembryonation technic have been described.
The method readily permits repeated sampling of the medium at various stages after infection (cumulative growth curves) or frequent exchanges of the medium (differential growth curve). However, the yield of infectious virus or of hemagglutinins is less than that observed in the intact chick embryo. The difference observed is greater than can be accounted for by the reduction in the available host cells and is assumed, therefore, to be due in part to interruption of blood and nutrient supply to the cells. This handicap can be overcome by the combined in ovo-deembryonation technic, in which deembryonation is performed at any desired time after infection of the intact chick embryo, and the medium is collected and analyzed after 1 to 3 hours of further incubation.
The value of the technic is demonstrated by the fact that liberation of virus from infected cells can be detected earlier than in the intact egg. Furthermore, it continues at a nearly constant rate for many hours, thus proving to be erroneous previous inference which had been based upon in ovo experiments.
The technic also permits readily the addition and subsequent removal of substances that might interfere with viral propagation. As an example a study was made of the effect of the receptor-destroying enzyme of V. cholerae (RDE) when added to the medium of eggs infected prior to deembryonation. By carefully grading the dose of virus and using an appropriate amount of RDE, one-step growth curves were obtained indicating that those cells not directly invaded by the seed virus were subsequently protected against infection by action of the enzyme. The smaller the amount of virus the less RDE was required in order to note a protective effect. With a decrease in the period of exposure to RDE regeneration of cell receptors became increasingly more apparent in that correspondingly greater amounts of virus were produced and liberated late in the incubation periods. These results confirmed and extended those reported by Stone.
More extensive applications of these technics will be reported in subsequent papers of this series.
THE OCCURRENCE DURING ACUTE INFECTIONS OF A PROTEIN NOT NORMALLY PRESENT IN THE BLOOD
Authors: Wood Harrison F. , McCarty Maclyn , Slater Robert J. 
Published: June 2004

A method is described for obtaining crystalline C-reactive protein from serous fluids in which the protein is associated with lipid. Most pathological fluids currently available as a source of this protein appear to fall in this category.
Crystalline C-reactive protein has its isoelectric point at pH 4.82 as determined by free electrophoresis in McIlvaine's buffer. Its mobility in the electrophoresis cell, both alone and after addition to normal serum, coincides with that of the ß-globulin fraction of the serum. In contrast to this finding, by the method of zone electrophoresis on a starch supporting medium the protein migrates with the γ1-globulin. The significance of this discrepancy is discussed. Studies in the ultracentrifuge indicate an s20,w of 7.5.
THE EFFECTS ON BIOLOGICAL MATERIALS OF FREEZING AND DRYING BY VACUUM SUBLIMATION
Authors: Greiff Donald , Pinkerton Henry 
Published: June 2004

A vacuum sublimation apparatus is described which will permit, (a) the removal of water from virus suspensions at temperatures ranging down to –80°C., (b) continuous operation with a minimum of attention from the investigator, (c) sealing off of samples at operating pressures (10–5 mm. Hg), (d) simultaneous lyophilization of aliquot samples at different temperatures, (e) isolation of a portion of the apparatus without disturbing the remainder of the system, and (f) determination of the end-point of sublimation without disturbing the samples.
The time required for drying 0.1 ml. of influenza virus suspension was shown to increase markedly with decrease of temperature, 8 days being required for dehydration at –80°C. in contrast to 2 days at –30°C. and 1 day at 0°C.