bluuebunny/crossref_metadata_2025_split huggingface dataset:
A CCACC Motif Mediates Negative Transcriptional Regulation of the Human Erythropoietin Receptor
Authors: Maouche Leïla , Lucien Nicole , Cartron Jean Pierre , Chrétien Stany 
Published: September 2004

We have previously shown that the +79 to +135 fragment of the human erythropoietin receptor (Epo‐R) acts negatively on the transcriptional activity and confers erythroid specificity to the gene [Maouche, L., Cartron, J.‐P. & Chrétien, S. (1994) Nucleic Acids Res. 22, 338–346]. In this work, we demonstrate that this effect is mediated by a CCACC motif that binds weakly to the simian virus 40 protein 1 (Sp1) factor and that the increase of the affinity for Sp1 augments transcription inhibition. The repression is not restricted to the human Epo‐R promoter, although it seems more efficient on heterologous promoters of erythroid genes.In chloramphenicol acetyl transferase constructs containing the mouse Epo‐R promoter, rearranged by retroviral long terminal repeat (LTR) insertion of murine erythroleukemia cell lines, we found that positioning the CCACC motif 3′ to the LTR represses the transcriptional activity mediated by the LTR in non‐erythroid cells.These results demonstrate that Epo‐R gene expression is negatively regulated by a CCACC or a GC box‐binding factor, which is most likely identical to the Sp1 transcription protein. Further data suggest that Sp1‐mediated negative regulation is not the result of a direct competition between Sp1 and another DNA‐binding protein.
2‐Chloro‐2′ ‐deoxyadenosine (Cladribine) and its Analogues are Good Substrates and Potent Selective Inhibitors of Escherichia coli Purine‐Nucleoside Phosphorylase
Authors: Bzowska Agnieszka , Kazimierczuk Zygmunt 
Published: September 2004

2‐Chloro‐2′‐deoxyadenosine (CldAdo), a nucleoside that has proven useful in the treatment of several chronic lymphoid malignancies, and its analogue, 2‐bromo‐2′‐deoxyadenosine, are both effective inhibitors of the bacterial (Escherichia coli) purine‐nucleoside phosphorylase (PNP), with Ki values of 4.5 μM and 6.3 μM, respectively. The examination of a series of base‐modified analogues of CldAdo has shown that several other compounds have similar inhibitor properties, and has indicated that 6‐benzyloxy‐2‐chloro‐9–(2′‐deoxy‐β‐d‐ribofuranosyl)purine is the most potent inhibitor with a Ki, value of 0.5 μM, competitive with respect to inosine (Ino).CldAdo itself and its base‐modified analogues, discounting those substituted at C(8), are also substrates for the E. coli PNP and undergo rapid glycosidic bond cleavage. CldAdo is degraded with substrate efficiency, i.e. Vmax/Km similar to that observed for Ino (130%), although the individual kinetic constants, Km and Vmax are both approximately an order of magnitude lower than for Ino.All compounds tested are totally inactive as substrates and inhibitors for mammalian (calf spleen) PNP and therefore constitute a new class of potent selective, although cleavable, inhibitors of bacterial phosphorylases.8‐Bromo‐2‐chloro‐2′‐deoxyadenosine and 8‐thio‐2‐chloro‐2′‐deoxyadenosine are the only base‐modified CldAdo derivatives showing inhibitory activity against MOLT‐3 (acute T‐cell leukemia) and U‐937 (histiocytic lymphoma) cells and, as shown in this study, are resistant to degradation by E. coli PNP. The above‐mentioned results suggest that both analogues could be effective as oral cytotoxic agents that are noncleavable by enteric bacteria.
Effect of pH on Sheep Liver Sorbitol Dehydrogenase Steady‐State Kinetics
Authors: Lindstad Rune I. , Mckinley‐Mckee John S. 
Published: September 2004

The variation with pH of the kinetic parameters for sorbitol oxidation and fructose reduction by sheep liver sorbitol dehydrogenase has been studied over the pH 5–10 range. The reaction is compulsory ordered in both directions with the coenzyme as the leading substrate, and the rate‐determining step in either direction is the enzyme‐coenzyme product dissociation. Throughout the pH range, the lack of a primary kinetic isotope effect on Vm with (2H8) sorbitol confirms that the ternary complexes are not of rate‐determining significance under maximum velocity conditions.The association rate constants for NAD and NADH increase and decrease, respectively, towards high pH. NAD binding to the enzyme is dependent upon pK values of 9.2 and 9.6. Whereas the dissociation rate constant for NAD release from the enzyme shows no pronounced variation with pH, NADH release is dependent upon pK values of 7.2 and 7.7.The kinetic constants that characterize the dependence on substrate concentration of the steady‐state rate of catalysis vary with pH in accordance with a single pK of 7.1 for sorbitol oxidation and of 7.7 for fructose reduction. These pK values reflect the ionization properties of a catalytically essential group, which is tentatively considered to be either the H2O/OH− ligand binding to the catalytic zinc atom or a histidine residue. Catalysis by sorbitol dehydrogenase, due to the absence of a second ionization contribution, appears not to involve any obligatory step of proton transfer to solution at the ternary complex level. A mechanism for sorbitol dehydrogenase catalysis is proposed.
A Glycoprotein Inhibitor of Pectin Methylesterase in Kiwi Fruit
Authors: Giovane Alfonso , Balestrieri Ciro , Quagliuolo Lucio , Castaldo Domenico , Servillo Luigi 
Published: September 2004

The pectin methylesterase inhibitor from kiwi fruit (Actinidia chinensis) was purified by a single‐step procedure based on affinity chromatography. Partially purified tomato pectin methylesterase was covalently bound to Sepharose. The affinity resin strongly and selectively binds the inhibitor, which could be eluted in high yield as a single, homogeneous and sharp peak by high salt concentration at pH 9.5 without loss of inhibitory activity. The purified protein possesses a molecular mass of 18 kDa, as estimated by SDS/PAGE, whereas by gel filtration under native conditions, its molecular mass appears to be 25 kDa. The inhibitor interacts with pectin methylesterase, forming a 1:1 complex, as demonstrated by gel‐filtration experiments.The inhibitor was glycosylated. Its glycidic portion can be removed by digestion with N‐glycosidase F after protein denaturation and, to a minor extent, by digestion with N‐glycosidase H. No glycidic residue could be removed by digesting the native protein with those N‐glycosidases. Antibodies against pectin methylesterase inhibitor were raised in rabbits and used to evidence protein expression during fruit ripening. The results showed that the inhibitor is present in the unripe fruit as an inactive precursor with a higher molecular mass (30 kDa) and is transformed into the active protein, most likely by proteinase action, during the course of the ripening process.
Vertical Price Control and Parallel Imports: Theory and Evidence
Authors: Maskus Keith E. , Chen Yongmin 
Published: September 2004

AbstractThe paper analyzes parallel imports, or goods traded without the authorization of a trademark owner. Parallel imports have multiple causes, including vertical price control, which the authors model. A manufacturer selling its product through an independent agent sets the wholesale price sufficiently low to induce a desired retail price abroad. This permits the agent to sell the product profitably in the originating market. Combined social surplus decreases and then increases in the cost of parallel trade. Restricting parallel imports benefits the manufacturer, but could raise or reduce global surplus. The econometric analysis indicates that the vertical‐control explanation of parallel imports is important.
Entry, Expansion, and Intensity in the US Export Boom, 1987–1992
Authors: Bernard Andrew B. , Jensen J. Bradford 
Published: September 2004

AbstractUS exports grew at 10.3% per year from 1987 to 1992, far faster than the economy as a whole. This paper examines sources of the manufacturing export boom, including entry, firm expansion, and export intensity. Most of the increase in exports came from increasing export intensity at existing exporters rather than from new entry into exporting. The small role of entry relative to export intensity offers support for the importance of sunk costs in the export market. Changes in exchange rates and rises in foreign income drove most of the export increase, while plant productivity increases played a smaller role.
Adam Smith and Noneconomic Objectives
Authors: Elmslie Bruce 
Published: September 2004

AbstractThis note looks at Smith's critiques of bounties (read “subsidies”) on exports. Smith's analysis of bounties foreshadowed the basic trade policy framework of distortions and noneconomic objectives. While Smith did not develop the theory of distortions, he captured the logic of the theory of noneconomic objectives and actually ranked policy alternatives based upon their relative social costs. Corden (1957) first ranked tariffs versus production subsidies within a noneconomic objectives framework, and Johnson (1960) first used the term in its modern sense, but the formulation of the general framework lies with Smith.
Patterns of Corporate Financing and Financial System Convergence in Europe
Authors: Murinde Victor , Agung Juda , Mullineux Andy 
Published: September 2004

AbstractThe paper investigates the possibility of convergence in the European Union (EU) in terms of the patterns of corporate financing by banks, bond markets, and stock markets; and in the context of whether the economies are converging towards an Anglo‐Saxon (capital‐market‐oriented) or a continental (bank‐oriented) financial system. GMM estimation of a dynamic fixed‐effects model is implemented to test for conditional and unconditional convergence using a panel of flow of funds data for the period 1972–1996 for seven EU member countries. It is found that the pattern of corporate financing is consistent with the pecking order theory of financing choices. Overall, the evidence suggests convergence of the EU financial systems on a variant of the Anglo‐Saxon model, depicting heavy reliance on internal financing as well as direct financing via equity and bond markets, while bank debt is becoming relatively less important.
Tangible User Interfaces (TUIs): A Novel Paradigm for GIS
Authors: Ratti Carlo , Wang Yao , Ishii Hiroshi , Piper Ben , Frenchman Dennis 
Published: September 2004

AbstractIn recent years, an increasing amount of effort has gone into the design of GIS user interfaces. On the one hand, Graphical User Interfaces (GUIs) with a high degree of sophistication have replaced line‐driven commands of first‐generation GIS. On the other hand, a number of alternative approaches have been suggested, most notably those based on Virtual Environments (VEs). In this paper we discuss a novel interface for GIS, which springs from recent work carried out in the field of Tangible User Interfaces (TUIs). The philosophy behind TUIs is to allow people to interact with computers via familiar tangible objects, therefore taking advantage of the richness of the tactile world combined with the power of numerical simulations. Two experimental systems, named Illuminating Clay and SandScape, are described here and their applications to GIS are examined. Conclusions suggest that these interfaces might streamline the landscape design process and result in a more effective use of GIS, especially when distributed decision‐making and discussion with non‐experts are involved.
Partitioning Spatial Model Uncertainty Based on Joint Spatial Simulation
Authors: Gertner George Z , Fang Shoufan , Wang Guangxing , Anderson Alan 
Published: September 2004

AbstractIn this study, an uncertainty analysis procedure for joint sequential simulation of multiple attributes of spatially explicit models used in geographical informational systems was developed based on regression analysis. This procedure utilizes information obtained from joint sequential simulation to establish the relationship between model uncertainty and variation of model inputs. Using this procedure, model variance can be partitioned by model input parameters on a cell by cell basis. In the partitioning, the correlation of neighboring cells is accounted for. With traditional uncertainty analysis methods, this is not possible. In a case study, spatial variation of soil erodibility from a joint sequential simulation of soil properties was analyzed. The results showed that the regression approach is a very effective method in the analysis of the relationship between variation of the model output and model input parameters. It was also shown for the case study that: (1) the uncertainty of soil erodibility of a cell is mainly propagated from its own soil properties; (2) the interactions of soil properties of neighboring cells could reduce uncertainty of soil erodibility; (3) it is sufficient for uncertainty analysis to include the nearest three neighboring cell groups; and (4) the largest uncertainty contributors vary by soil properties and location.
Data Integration Issues for a Farm Decision Support System
Authors: Jones Marion , Taylor George 
Published: September 2004

AbstractThis paper explores data integration and compatibility issues raised during the development of a prototype spatial decision support system (SDSS) as a support tool for the farm manager of the University of Central Lancashire's farm at Newton Rigg and as a teaching resource for staff and students on campus. Metadata concerns and interoperability problems are addressed in detail. The paper outlines the proposed model for the SDSS and issues identified during the investigation of the users’ requirements and the analysis of the underlying spatial data sets. The initial data issues relate to the identification of existing and missing data sets (Parker et al. 1996) and the creation of metadata describing the data sets. The second area to be explored concerns interoperability issues. This is relevant when users must access more than one dataset using distributed computing resources (Sondheim et al. 1999).
Spatial Differences in Multi‐Resolution Urban Automata Modeling
Authors: Dietzel Charles , Clarke Keith C 
Published: September 2004

AbstractThe last decade has seen a renaissance in spatial modeling. Increased computational power and the greater availability of spatial data have aided in the creation of new modeling techniques for studying and predicting the growth of cities and urban areas. Cellular automata is one modeling technique that has become widely used and cited in the literature; yet there are still some very basic questions that need to be answered with regards to the use of these models, specifically relating to the spatial resolution during calibration and how it can impact model forecasts. Using the SLEUTH urban growth model (Clarke et al. 1997), urban growth for San Joaquin County (CA) is projected using three different spatial grains, based on four calibration routines, and the spatial differences between the model outputs are examined. Model outputs show that calibration at finer scaled data results in different parameter sets, and forecasting of urban growth in areas that was not captured through the use of more coarse data.
The geochemical diversity of neogene clay deposits in Crete and its implications for provenance studies of Minoan pottery*
Authors: Hein A. , Day P. M. , Quinn P. S. , Kilikoglou V. 
Published: September 2004

The determination of provenance probably forms the primary role of geochemical analyses in archaeological ceramic studies. In what has comprised a successful field of study, the ultimate basis for such research has been the comparison of pottery compositions with the geochemical diversity displayed by clay deposits within a given study area. Although such studies are now common, the understanding of chemical and mineralogical variability in ceramic raw materials has been somewhat neglected, with the dominance of assumptions rather than the actual analysis of clays. In this paper, a study is presented of Neogene clays in Crete (Greece), a clay type commonly used in ancient and modern pottery production. Sixty‐one samples were taken from 28 locations in the central and eastern parts of the island, to reveal both intra‐ and inter‐deposit variability. In one deposit chosen for multiple sampling, the 14 samples display great variability in the alkali elements, Fe and Co, and to a lesser extent in the REEs. Many of the geographically separate deposits differ from each other in chemical composition, with Eastern Cretan deposits showing higher REE concentrations and higher Th/Sc ratios, whereas Central Cretan deposits of younger geological stages are characterized by a lower Th/U ratio. Mineralogical analysis by XRD is used to explain aspects of the geochemical variability of the clays.
The production and technology of glazed ceramics from the middle ages, found in the saepinum territory (Italy): a multimethodic approach*
Authors: Comodi P. , Bernardi M. , Bentivoglio A. , Gatta G. D. , Zanazzi P. F. 
Published: September 2004

A collection of ceramics from the Middle Ages found in Altilia and Terravecchia (the Saepinum area, Campobasso, Italy) were characterized by using different mineralogical analyses to investigate their provenance and production techniques. The body ceramic was investigated using Rietveld phase analysis of X‐ray powder diffraction patterns, X‐ray fluorescence spectrometry and scanning electron microscopy. The chemical compositions of the coatings were measured by scanning electron microscopy and their mineralogical compositions were determined using a particular technique of X‐ray small‐angle scattering (SAS) optimized for studies of thin films. Moreover, the material used for decoration was studied using micro‐Raman spectroscopy. The archaeometric results confirmed the distinction into two different ceramic classes, already individuated from archaeological analysis: the Altilia objects belong to the protomajolica class, whereas the objects from Terravecchia are RMR (ramina‐manganese‐red) ceramics. A comparison between the chemical and mineralogical compositions of good‐quality ceramic objects and those of waste products indicated local production of the ceramics. A sharp distinction was found in the chemical composition of the coatings: the Altilia products have tin‐opacified lead glazes, while the Terravecchia ones have transparent high‐lead glazes. Among the Altilia products, the unsuccessful process that produced a large quantity of discarded materials was attributed to the high lead content of the glazes. In fact, the principal advantage of the high lead content was to make the preparation and application of the glaze suspension easier, but the risk of reduction of lead oxide to metallic lead was greatly increased. Using micro‐Raman spectroscopy, the following minerals were identified as pigments: pyrolusite for the dark colour, malachite for green, lepidocrocite for yellow and hematite for red.
Binary Bacterial Toxins: Biochemistry, Biology, and Applications of CommonClostridiumandBacillusProteins
Authors: Barth Holger , Aktories Klaus , Popoff Michel R. , Stiles Bradley G. 
Published: September 2004

SUMMARYCertain pathogenic species of Bacillus and Clostridium have developed unique methods for intoxicating cells that employ the classic enzymatic “A-B” paradigm for protein toxins. The binary toxins produced by B. anthracis, B. cereus, C. botulinum, C. difficile, C. perfringens, and C. spiroforme consist of components not physically associated in solution that are linked to various diseases in humans, animals, or insects. The “B” components are synthesized as precursors that are subsequently activated by serine-type proteases on the targeted cell surface and/or in solution. Following release of a 20-kDa N-terminal peptide, the activated “B” components form homoheptameric rings that subsequently dock with an “A” component(s) on the cell surface. By following an acidified endosomal route and translocation into the cytosol, “A” molecules disable a cell (and host organism) via disruption of the actin cytoskeleton, increasing intracellular levels of cyclic AMP, or inactivation of signaling pathways linked to mitogen-activated protein kinase kinases. Recently, B. anthracis has gleaned much notoriety as a biowarfare/bioterrorism agent, and of primary interest has been the edema and lethal toxins, their role in anthrax, as well as the development of efficacious vaccines and therapeutics targeting these virulence factors and ultimately B. anthracis. This review comprehensively surveys the literature and discusses the similarities, as well as distinct differences, between each Clostridium and Bacillus binary toxin in terms of their biochemistry, biology, genetics, structure, and applications in science and medicine. The information may foster future studies that aid novel vaccine and drug development, as well as a better understanding of a conserved intoxication process utilized by various gram-positive, spore-forming bacteria.
Biodiversity of Vibrios
Authors: Thompson Fabiano L. , Iida Tetsuya , Swings Jean 
Published: September 2004

SUMMARYVibrios are ubiquitous and abundant in the aquatic environment. A high abundance of vibrios is also detected in tissues and/or organs of various marine algae and animals, e.g., abalones, bivalves, corals, fish, shrimp, sponges, squid, and zooplankton. Vibrios harbour a wealth of diverse genomes as revealed by different genomic techniques including amplified fragment length polymorphism, multilocus sequence typing, repetetive extragenic palindrome PCR, ribotyping, and whole-genome sequencing. The 74 species of this group are distributed among four different families, i.e.,Enterovibrionaceae,Photobacteriaceae,Salinivibrionaceae, andVibrionaceae. Two new genera, i.e.,Enterovibrio norvegicusandGrimontia hollisae, and 20 novel species, i.e.,Enterovibrio coralii,Photobacterium eurosenbergii,V. brasiliensis,V. chagasii,V. coralliillyticus,V. crassostreae,V. fortis,V. gallicus,V. hepatarius,V. hispanicus,V. kanaloaei,V. neonatus,V. neptunius,V. pomeroyi,V. pacinii,V. rotiferianus,V. superstes,V. tasmaniensis,V. ezurae, andV. xuii, have been described in the last few years. Comparative genome analyses have already revealed a variety of genomic events, including mutations, chromosomal rearrangements, loss of genes by decay or deletion, and gene acquisitions through duplication or horizontal transfer (e.g., in the acquisition of bacteriophages, pathogenicity islands, and super-integrons), that are probably important driving forces in the evolution and speciation of vibrios. Whole-genome sequencing and comparative genomics through the application of, e.g., microarrays will facilitate the investigation of the gene repertoire at the species level. Based on such new genomic information, the taxonomy and the species concept for vibrios will be reviewed in the next years.
Effects of Length and Location on the Cellular Response to Double-Stranded RNA
Authors: Wang Qiaoqiao , Carmichael Gordon G. 
Published: September 2004

SUMMARYSince double-stranded RNA (dsRNA) has not until recently generally been thought to be deliberately expressed in cells, it has commonly been assumed that the major source of cellular dsRNA is viral infections. In this view, the cellular responses to dsRNA would be natural and perhaps ancient antiviral responses. While the cell may certainly react to some dsRNAs as an antiviral response, this does not represent the only response or even, perhaps, the major one. A number of recent observations have pointed to the possibility that dsRNA molecules are not seen only as evidence of viral infection or recognized for degradation because they cannot be translated. In some instances they may also play important roles in normal cell growth and function. The purpose of this review is to outline our current understanding of the fate of dsRNA in cells, with a focus on the apparent fact that their fates and functions appear to depend critically not only on where in the cell dsRNA molecules are found, but also on how long they are and perhaps on how abundant they are.