bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cloning, Characterization, and Immunolocalization of a Mycorrhiza-Inducible 1-Deoxy-D-Xylulose 5-Phosphate Reductoisomerase in Arbuscule-Containing Cells of Maize
Authors: Hans Joachim , Hause Bettina , Strack Dieter , Walter Michael H. 
Published: February 2004

Abstract
Colonization of plant roots by symbiotic arbuscular mycorrhizal fungi frequently leads to the accumulation of several apocarotenoids. The corresponding carotenoid precursors originate from the plastidial 2-C-methyl-d-erythritol 4-phosphate pathway. We have cloned and characterized 1-deoxy-d-xylulose 5-phosphate reductoisomerase (DXR), catalyzing the first committed step of the pathway, from maize (Zea mays). Functional identification was accomplished by heterologous expression of sequences coding for the mature protein in Escherichia coli. DXR is up-regulated in maize roots during mycorrhization as shown at transcript and protein levels, but is also abundant in leaves and young seedlings. Inspection of sequenced genomes and expressed sequence tag (EST) databases argue for a single-copy DXR gene. Immunolocalization studies in mycorrhizal roots using affinity-purified antibodies revealed a DXR localization in plastids around the main symbiotic structures, the arbuscules. DXR protein accumulation is tightly correlated with arbuscule development. The highest level of DXR protein is reached around maturity and initial senescence of these structures. We further demonstrate the formation of a DXR-containing plastidial network around arbuscules, which is highly interconnected in the mature, functional state of the arbuscules. Our findings imply a functional role of a still unknown nature for the apocarotenoids or their respective carotenoid precursors in the arbuscular life cycle.
Localization of an Ascorbate-Reducible Cytochrome b561 in the Plant Tonoplast
Authors: Griesen Daniel , Su Dan , Bérczi Alajos , Asard Han 
Published: February 2004

AbstractAs a free radical scavenger, and cofactor, ascorbate (ASC) is a key player in the regulation of cellular redox processes. It is involved in responses to biotic and abiotic stresses and in the control of enzyme activities and metabolic reactions. Cytochromes (Cyts) b561 catalyze ASC-driven trans-membrane electron transport and contribute to ASC-mediated redox reactions in subcellular compartments. Putative Cyts b561 have been identified in Arabidopsis (ecotype Columbia) on the basis of sequence similarity to their mammalian counterparts. However, little is known about the function or subcellular localization of this unique class of membrane proteins. We have expressed one of the putative Arabidopsis Cyt b561 genes (CYBASC1) in yeast and we demonstrate that this protein encodes an ASC-reducible b-type Cyt with absorbance characteristics similar to that of other members of this family. Several lines of independent evidence demonstrate that CYBASC1 is localized at the plant tonoplast (TO). Isoform-specific antibodies against CYBASC1 indicate that this protein cosediments with the TO marker on sucrose gradients. Moreover, CYBASC1 is strongly enriched in TO-enriched membrane fractions, and TO fractions contain an ASC-reducible b-type Cyt with α-band absorbance maximum near 561 nm. The TO ASC-reducible Cyt has a high specific activity, suggesting that it is a major constituent of this membrane. These results provide evidence for the presence of trans-membrane redox components in this membrane type, and they suggest the coupling of cytoplasmic and vacuolar metabolic reactions through ASC-mediated redox activity.
Profiling of Arabidopsis Secondary Metabolites by Capillary Liquid Chromatography Coupled to Electrospray Ionization Quadrupole Time-of-Flight Mass Spectrometry
Authors: von Roepenack-Lahaye Edda , Degenkolb Thomas , Zerjeski Michael , Franz Mathias , Roth Udo , Wessjohann Ludger , Schmidt Jürgen , Scheel Dierk , Clemens Stephan 
Published: February 2004

Abstract
Large-scale metabolic profiling is expected to develop into an integral part of functional genomics and systems biology. The metabolome of a cell or an organism is chemically highly complex. Therefore, comprehensive biochemical phenotyping requires a multitude of analytical techniques. Here, we describe a profiling approach that combines separation by capillary liquid chromatography with the high resolution, high sensitivity, and high mass accuracy of quadrupole time-of-flight mass spectrometry. About 2,000 different mass signals can be detected in extracts of Arabidopsis roots and leaves. Many of these originate from Arabidopsis secondary metabolites. Detection based on retention times and exact masses is robust and reproducible. The dynamic range is sufficient for the quantification of metabolites. Assessment of the reproducibility of the analysis showed that biological variability exceeds technical variability. Tools were optimized or established for the automatic data deconvolution and data processing. Subtle differences between samples can be detected as tested with the chalcone synthase deficient tt4 mutant. The accuracy of time-of-flight mass analysis allows to calculate elemental compositions and to tentatively identify metabolites. In-source fragmentation and tandem mass spectrometry can be used to gain structural information. This approach has the potential to significantly contribute to establishing the metabolome of Arabidopsis and other model systems. The principles of separation and mass analysis of this technique, together with its sensitivity and resolving power, greatly expand the range of metabolic profiling.
Tissue- and Age-Dependent Differences in the Complexation of Cadmium and Zinc in the Cadmium/Zinc Hyperaccumulator Thlaspi caerulescens (Ganges Ecotype) Revealed by X-Ray Absorption Spectroscopy
Authors: Küpper Hendrik , Mijovilovich Ana , Meyer-Klaucke Wolfram , Kroneck Peter M.H. 
Published: February 2004

Abstract
Extended x-ray absorption fine structure measurements were performed on frozen hydrated samples of the cadmium (Cd)/zinc (Zn) hyperaccumulator Thlaspi caerulescens (Ganges ecotype) after 6 months of Zn2+ treatment with and without addition of Cd2+. Ligands depended on the metal and the function and age of the plant tissue. In mature and senescent leaves, oxygen ligands dominated. This result combined with earlier knowledge about metal compartmentation indicates that the plants prefer to detoxify hyperaccumulated metals by pumping them into vacuoles rather than to synthesize metal specific ligands. In young and mature tissues (leaves, petioles, and stems), a higher percentage of Cd was bound by sulfur (S) ligands (e.g. phytochelatins) than in senescent tissues. This may indicate that young tissues require strong ligands for metal detoxification in addition to the detoxification by sequestration in the epidermal vacuoles. Alternatively, it may reflect the known smaller proportion of epidermal metal sequestration in younger tissues, combined with a constant and high proportion of S ligands in the mesophyll. In stems, a higher proportion of Cd was coordinated by S ligands and of Zn by histidine, compared with leaves of the same age. This may suggest that metals are transported as stable complexes or that the vacuolar oxygen coordination of the metals is, like in leaves, mainly found in the epidermis. The epidermis constitutes a larger percentage of the total volume in leaves than in stems and petioles. Zn-S interaction was never observed, confirming earlier results that S ligands are not involved in Zn resistance of hyperaccumulator plants.
A Transcriptomic and Proteomic Characterization of the Arabidopsis Mitochondrial Protein Import Apparatus and Its Response to Mitochondrial Dysfunction
Authors: Lister Ryan , Chew Orinda , Lee May-Nee , Heazlewood Joshua L. , Clifton Rachel , Parker Karen L. , Millar A. Harvey , Whelan James 
Published: February 2004

Abstract
Mitochondria import hundreds of cytosolically synthesized proteins via the mitochondrial protein import apparatus. Expression analysis in various organs of 19 components of the Arabidopsis mitochondrial protein import apparatus encoded by 31 genes showed that although many were present in small multigene families, often only one member was prominently expressed. This was supported by comparison of real-time reverse transcriptase-polymerase chain reaction and microarray experimental data with expressed sequence tag numbers and massive parallel signature sequence data. Mass spectrometric analysis of purified mitochondria identified 17 import components, their mitochondrial sub-compartment, and verified the presence of TIM8, TIM13, TIM17, TIM23, TIM44, TIM50, and METAXIN proteins for the first time, to our knowledge. Mass spectrometry-detected isoforms correlated with the most abundant gene transcript measured by expression data. Treatment of Arabidopsis cell culture with mitochondrial electron transport chain inhibitors rotenone and antimycin A resulted in a significant increase in transcript levels of import components, with a greater increase observed for the minor isoforms. The increase was observed 12 h after treatment, indicating that it was likely a secondary response. Microarray analysis of rotenone-treated cells indicated the up-regulation of gene sets involved in mitochondrial chaperone activity, protein degradation, respiratory chain assembly, and division. The rate of protein import into isolated mitochondria from rotenone-treated cells was halved, even though rotenone had no direct effect on protein import when added to mitochondria isolated from untreated cells. These findings suggest that transcription of import component genes is induced when mitochondrial function is limited and that minor gene isoforms display a greater response than the predominant isoforms.
Coordinated Regulation of Genes for Secretion in Tobacco at Late Developmental Stages: Association with Resistance against Oomycetes
Authors: Hugot Karine , Rivière Marie-Pierre , Moreilhon Chimène , Dayem Manal A. , Cozzitorto Joseph , Arbiol Gilles , Barbry Pascal , Weiss Catherine , Galiana Eric 
Published: February 2004

AbstractBesides the systemic acquired resistance (SAR) induced in response to microbial stimulation, host plants may also acquire resistance to pathogens in response to endogenous stimuli associated with their own development. In tobacco (Nicotiana tabacum), the vegetative-to-flowering transition comes along with a susceptibility-to-resistance transition to the causal agent of black shank disease, the oomycete Phytophthora parasitica. This resistance affects infection effectiveness and hyphal expansion and is associated with extracellular accumulation of a cytotoxic activity that provokes in vitro cell death of P. parasitica zoospores. As a strategy to determine the extracellular events important for restriction of pathogen growth, we screened the tobacco genome for genes encoding secreted or membrane-bound proteins expressed in leaves of flowering plants. Using a signal sequence trap approach in yeast (Saccharomyces cerevisiae), 298 clones were selected that appear to encode for apoplastic, cell wall, or membrane-bound proteins involved in stress response, in plant defense, or in cell wall modifications. Microarray and northern-blot analyses revealed that, at late developmental stages, leaves were characterized by the coordinate up-regulation of genes involved in SAR and in peroxidative cross-linking of structural proteins to cell wall. This suggests the potential involvement of these genes in extracellular events that govern the expression of developmental resistance. The analysis of the influence of salicylic acid on mRNA accumulation also indicates a more complex network for regulation of gene expression at a later stage of tobacco development than during SAR. Further characterization of these genes will permit the formulation of hypotheses to explain resistance and to establish the connection with development.
The Future of Sovereignty in Multilevel Governance Europe ‐ A Constructivist Reading
Authors: Aalberts Tanja E. 
Published: February 2004

AbstractMultilevel governance presents a depiction of contemporary structures in EU Europe as consisting of overlapping authorities and competing competencies. By focusing on emerging non‐anarchical structures in the international system, hence moving beyond the conventional hierarchy/anarchy dichotomy to distinguish domestic and international arenas, this seems a radical transformation of the familiar Westphalian system and to undermine state sovereignty. Paradoxically, however, the principle of sovereignty proves to be resilient despite its alleged empirical decline. This article argues that social constructivism can explain the paradox, by considering sovereign statehood as a process‐dependent institutional fact, and by showing that multilevel governance can feed into this process.
Indicators and Targets for Social Inclusion in the European Union
Authors: Atkinson Anthony B. , Marlier Eric , Nolan Brian 
Published: February 2004

AbstractIn December 2001, the Laeken European Council adopted a set of commonly agreed and defined indicators for social inclusion. These should play a central role in monitoring the performance of Member States in making progress towards the key EU objectives in this area set by the Nice European Council in 2000, and represent a major step forward in the development of EU social policy. This article reviews the scientific and political basis on which the indicators were selected, and the implications for the future development of policy‐making in Europe. It describes the key features of the indicators and some of the ways in which they can be developed. Finally, it investigates some important issues that need to be addressed when setting quantitative targets in the context of the social inclusion process.
A Bridge Too Phare? EU Pre‐Accession Aid and Capacity‐Building in the Candidate Countries
Authors: Bailey David , De Propris Lisa 
Published: February 2004

AbstractThe imminent large‐scale EU enlargement raises important questions regarding the success of Phare as one of the Pre‐Accession Funds in preparing candidate countries' institutions for Structural Funding, the need to reform EU regional policy itself, and to what extent the Commission is using Phare to build regional‐level institutions and shift an enlarged EU towards multi‐level governance. Despite some successes, Phare will not be able to deliver everything it was set up for, and a coherent set of post‐accession transition policies will need to be set up as part of the next reform of the Structural Funds to ensure that the process of learning and adjustment leading to the adoption of the acquis does not stall with the new membership.
The CAP and EU Enlargement: Prospects for an Alternative Strategy to Avoid the Lock‐in of CAP Support
Authors: Daugbjerg Carsten , Swinbank Alan 
Published: February 2004

AbstractThe integration of the central and east European countries (CEECs) into the Common Agricultural Policy (CAP) could become a major problem. At the Copenhagen European summit in December 2002, the EU agreed a transitional period with a gradual phasing in of direct payments. However, this strategy will not solve the problems of the CAP: budgetary limits remain problematic, the policy ignores possible developments in the World Trade Organization (WTO), and the extension of direct payments to the CEECs will further capitalize, and hence lock‐in, agricultural support. The latter makes future reform even more difficult and, to overcome these problems, we suggest an alternative strategy to integrate the CEECs into the CAP. The EU should phase out direct payments by applying a bond scheme. Finally, we consider whether this option is politically viable.
New Governance in the European Union: A Theoretical Perspective
Authors: Eberlein Burkard , Kerwer Dieter 
Published: February 2004

AbstractNew modes of governance based on voluntary performance standards, rather than compulsory regulation, have gained salience in the European Union (EU). Can these new modes of governance offer a credible solution to the current challenges faced by EU policy‐making? In this article, we assess the potential of new governance in the light of the theory of democratic experimentalism. This theoretical perspective suggests, first, that co‐ordination by voluntary performance standards can lead to more effective rules and more opportunities for political participation; second, that the scope of this mode of governance in the EU is not confined to cases which are explicitly flagged as new governance; and third, that one of the main problems is how a voluntary mode of governance can coexist with compulsory regulation.
Renationalizing or Regrouping? EU Foreign Policy Since 11 September 2001
Authors: Hill Christopher 
Published: February 2004

AbstractThis article considers whether the most recent phase of European foreign policy‐making, since the atrocity of 11 September, has exposed fatal flaws in the EU's Common Foreign and Security Policy (CFSP), or whether it is too soon for dismissive judgements. It asks to what extent Member States have fallen back on their own resources, and to what extent there are signs of regrouping, so as to take the CFSP on to the next stage. It examines the main substantive challenges which have preoccupied Europe since 11 September, some of the key foreign policy issues which predated but then became complicated by it, and finally the more structural issues such as the European Security and Defence Policy (ESDP), the Convention on constitutional reform, and enlargement. It concludes that the current crisis is not rendering European foreign policy redundant, and that there continues to be the will, if not always the capacity, to produce collective action.
EU Enlargement and Immigration
Authors: Kraus Margit , Schwager Robert 
Published: February 2004

AbstractThis article assesses the consequences of EU enlargement for east–west migration. It is argued that expectations on future economic, social and political variables are crucial for immediate immigration. Specifically, if EU membership is refused, fear of future restrictions on immigration will lead to increased current migration. Moreover, EU accession is likely to reduce income gaps between the accession countries and the current Member States reducing the incentives to emigrate. We conclude that granting EU accession to eastern European countries will not necessarily induce massive east–west migration flows.
E Pluribus Unum? Creative Disagreement about Legitimacy in the EU
Authors: Lord Christopher , Magnette Paul 
Published: February 2004

AbstractThis article considers how a plurality of views on how the EU ought to be legitimated may even contribute to its overall legitimacy and not, as is often assumed, to its contestedness as a polity. It draws lessons for the EU from a recent turn in the literature on legitimacy towards analysing political systems as mechanisms for mediating between several views of legitimacy, rather than articulating any one. It identifies a range of views on how the Union ought to be legitimated. It appraises alternative mechanisms for combining or choosing between those views. It concludes with lessons for the constitutional development of the Union.
Representation and Agenda Setting
Authors: Jones Bryan D. , Baumgartner Frank R. 
Published: February 2004

We develop a new approach to the study of representation based on agenda setting and attention allocation. We ask the fundamental question: do the policy priorities of the public and of the government correspond across time? To assess the policy priorities of the mass public, we have coded the Most Important Problem data from Gallup polls across the postwar period into the policy content categories developed by the Policy Agendas Project (Baumgartner & Jones, 2002). Congressional priorities were assessed by the proportion of total hearings in a given year focusing on those same policy categories, also from the Agendas Project. We then conducted similar analyses on public laws and most important laws, similarly coded. Finally we analyzed the spatial structure of public and congressional agendas using the Shepard‐Kruskal non‐metric multidimensional scaling algorithm. Findings may be summarized as follows: First, there is an impressive congruence between the priorities of the public and the priorities of Congress across time. Second, there is substantial evidence of congruence between the priorities of the public and lawmaking in the national government, but the correspondence is attenuated in comparison to agendas. Third, although the priorities of the public and Congress are structurally similar, the location of issues within the structure differs between Congress and the general public. The public “lumps” its evaluation of the nations most important problems into a small number of categories. Congress “splits” issues out, handling multiple issues simultaneously. Finally, the public tends to focus on a very constrained set of issues, but Congress juggles many more issues. The article has strong implications for the study of positional representation as well, because for traditional representation to occur, there must be correspondence between the issue‐priorities of the public and the government. We find substantial evidence for such attention congruence here.
Punctuated Equilibrium, Bureaucratization, and Budgetary Changes in Schools
Authors: Robinson Scott E. 
Published: February 2004

For half of a century, models of nonrational behavior have grown in popularity for explaining the behavior of administrative organizations. However, models of nonrational behavior are notoriously difficult to test because nonrational behavior is often difficult to separate from fully rational behavior. Recent research has suggested that particular types of nonrational processes should produce “punctuated” equilibria rather than “instantaneous” equilibria. In these nonrational processes, a decision maker underresponds to changes for a long period of time. Once pressure for change becomes overwhelming, the decision maker adopts a radical change. This is called “punctuation.” The key to identifying this type of nonrationality of a process's rationality is the comparative success of fitting the observed behavior to “punctuated” rather than “instantaneous” equilibria. True, Jones, and Baumgartner (1999) developed a method for comparing the distribution of decision outputs as a strategy for assessing the relative degree of “punctuation” in the decision processes. By assessing the kurtosis (or “peakedness”) of the distribution of decision outputs, one can get a sense of the excess (compared with a standard, normal distribution) of low and high rates of change–a sign of punctuated equilibrium.This article extends these recent developments by adapting the method to a comparative kurtosis framework. The results suggest that bureaucracy in K–12 schools serves to reduce (rather than amplify) the punctuations in budgeting processes. The article concludes with a discussion of the potential extension of the empirical results and modifications to the testing procedure.
A Multipopulation Comparison of the Diffusion of Public Organizations and Policies across Space and Time
Authors: Jensen Jason L. 
Published: February 2004

This study examined the longitudinal spatial diffusion of state government policies and their related implementation organizations in the American states. The impact of coercive, institutional, and competitive processes on policy and state agency adoption were considered, as well as how aspects of the underlying policy can impact the degree of spatial diffusion. The rises of 27 different policy populations were analyzed over time, each representing not only a different policy form but a distinct implementation organization.The policy adoption/spatial diffusion relationship across all populations was examined and results showed that the degree of spatial diffusion varied greatly. Analysis of potential relationship moderators indicated that federal impetus (coercive processes) led to an absence of spatial diffusion. Policies with an institutional basis also showed an absence of spatial diffusion while competition‐based policies diffused spatially.