Key Example (key + example)

Distribution by Scientific Domains

Selected Abstracts

Assessing the impact of transcriptomics, proteomics and metabolomics on fungal phytopathology

SUMMARY Peer-reviewed literature is today littered with exciting new tools and techniques that are being used in all areas of biology and medicine. Transcriptomics, proteomics and, more recently, metabolomics are three of these techniques that have impacted on fungal plant pathology. Used individually, each of these techniques can generate a plethora of data that could occupy a laboratory for years. When used in combination, they have the potential to comprehensively dissect a system at the transcriptional and translational level. Transcriptomics, or quantitative gene expression profiling, is arguably the most familiar to researchers in the field of fungal plant pathology. Microarrays have been the primary technique for the last decade, but others are now emerging. Proteomics has also been exploited by the fungal phytopathogen community, but perhaps not to its potential. A lack of genome sequence information has frustrated proteomics researchers and has largely contributed to this technique not fulfilling its potential. The coming of the genome sequencing era has partially alleviated this problem. Metabolomics is the most recent of these techniques to emerge and is concerned with the non-targeted profiling of all metabolites in a given system. Metabolomics studies on fungal plant pathogens are only just beginning to appear, although its potential to dissect many facets of the pathogen and disease will see its popularity increase quickly. This review assesses the impact of transcriptomics, proteomics and metabolomics on fungal plant pathology over the last decade and discusses their futures. Each of the techniques is described briefly with further reading recommended. Key examples highlighting the application of these technologies to fungal plant pathogens are also reviewed. [source]

Could the tree diversity pattern in Europe be generated by postglacial dispersal limitation?

Jens-Christian Svenning
Abstract The relative importance of contemporary climate and history as controls of geographical diversity patterns is intensely debated. A key example is the controversy over the extent to which temperate tree distributions and diversity patterns reflect postglacial dispersal limitation. Here, we focus on Central and Northern Europe, and show that recent estimates of tree migration rates < 100 m year,1 imply that many species have probably not reached equilibrium with climate in this region. We then demonstrate that geographical accessibility from glacial refuges explains 78% of the geographical variation in the region's tree diversity and is a much stronger diversity predictor than climate. Finally, we show that realistic estimates of migration rates can be derived from the observed tree diversity pattern by assuming it to be purely dispersal driven. In conclusion, the tree diversity pattern in Central and Northern Europe could, to a large extent, be a result of postglacial dispersal limitation. [source]

Nation to Nation: Defining New Structures of Development in Northern Quebec

Caroline Desbiens
Abstract: In February 2002, the Crees of Quebec and the Quebec government signed a new agreement that was designed to implement new structures of economic development in northern Quebec. The document, known as "La Paix des Braves" (Peace of the Braves), was characterized as a "nation-to-nation" agreement and promises greater participation by the Crees in the management and exploitation of natural resources on the territory. Starting from the premise that the Crees and the Québécois do not simply compete for the resources of James Bay but can be said to define and firm up the boundaries of their respective nation in and through the use of these resources, this article explores the close intertwining of colonialism, culture, and the economy in James Bay, as well as its potential impact on the new agreement. First, it analyzes how the Crees and the Québécois have articulated nationhood in relation to land and resources, particularly over the past three decades. Second, it examines how these discourses are informed by a third national scale, that of Canada. The intersection among nature, nation, and economic development in northern Quebec is a key example of how resources are embedded in complex national geographies that are shaped across a broad historical span. Although sustainability is often defined in terms of the needs of future generations, this article calls for greater attention to past colonial and political relations in defining structures of development that ensure the renewal of resources. [source]

Nature-Society Interactions in the Pacific Islands

Patrick D. Nunn
ABSTRACT This paper focuses on nature,society interactions in the Pacific Islands before European contact about 200 years ago. It argues that the character of early interactions was decided by both the nature of a particular island environment and the intentions of the human settlers. Throughout the pre-European contact human history of the Pacific Islands, environmental changes of extraneous cause have been the main control of societal and cultural change. This environmental determinist view is defended using many examples. The contrary (and more popular) cultural determinist view of societal change in the Pacific Islands is shown to be based on largely spurious data and argument. A key example discussed is the ,AD 1300 Event', a time of rapid temperature and sea-level fall which had severe, abrupt and enduring effects on Pacific Island societies. It is important to acknowledge the role of environmental change in cultural transformation in this region. [source]

Theorizing Diaspora: Perspectives on "Classical" and "Contemporary" Diaspora

Michele Reis
Cohen (1997) employed the term "classical" diaspora in reference to the Jews. Indeed, a vast corpus of work recognizes the Jewish people as examples of quintessential diasporic groups. However, a broader conceptualization of the term diaspora allows for the inclusion of immigrant communities that would be otherwise sidelined in the conventional literature on diaspora. This study is therefore a departure from the traditional diasporic literature, which tends to use the Jewish Diaspora as the archetype. It favours, rather, the classification of three principal broad historical waves in which the Jewish Diaspora can be interpreted as part of a classical period. The historicizing of diasporization for the purpose of this paper is achieved by an empirical discussion of the three major historical waves that influenced the diasporic process throughout the world: the Classical Period, the Modern Period, and the Contemporary or Late-modern Period. The paper discusses these three critical phases in the following manner: first, reference is made to the Classical Period, which is associated primarily with ancient diaspora and ancient Greece. The second historical phase analyses diaspora in relation to the Modern Period, which can be interpreted as a central historical fact of slavery and colonization. This section can be further subdivided into three large phases: (1) the expansion of European capital (1500,1814), (2) the Industrial Revolution (1815,1914), and (3) the Interwar Period (1914,1945). The final major period of diasporization can be considered a Contemporary or Late-modern phenomenon. It refers to the period immediately after World War II to the present day, specifying the case of the Hispanics in the United States as one key example. The paper outlines some aspects of the impact of the Latin American diaspora on the United States, from a socio-economic and politico-cultural point of view. While the Modern and Late-modern periods are undoubtedly the most critical for an understanding of diaspora in a modern, globalized context, for the purpose of this paper, more emphasis is placed on the latter period, which illustrates the progressive effect of globalization on the phenomenon of diasporization. The second period, the Modern Phase is not examined in this paper, as the focus is on a comparative analysis of the early Classical Period and the Contemporary or Late-modern Period. The incorporation of diaspora as a unit of analysis in the field of international relations has been largely neglected by both recent and critical scholarship on the subject matter. While a growing number of studies focus on the increasing phenomenon of diasporic communities, from the vantage of social sciences, the issue of diaspora appears to be inadequately addressed or ignored altogether. Certain key factors present themselves as limitations to the understanding of the concept, as well as its relevance to the field of international relations and the social sciences as a whole. This paper is meant to clarify some aspects of the definition of diaspora by critiquing the theories in the conventional literature, exposing the lacunae in terms of interpretation of diaspora and in the final analysis, establishing a historiography that may be useful in comparing certain features of "classical" diaspora and "contemporary" diaspora. The latter part of the paper is intended to provide illustrations of a contemporary diasporic community, using the example of Hispanics in the United States. [source]

Control Modes in the Age of Transnational Governance

LAW & POLICY, Issue 3 2008
The article starts with the observation that there are overlaps in, so far, largely unrelated research programs concerned with the legalization in international relations, on the one hand, and transnational regulation and governance, on the other. The analysis of the literature at the interface between the "fourth strata of the geology of international law" and the "governance in the age of regulation" literatures reveals a substantial common interest in structures of transnational regulatory governance. At the same time, the theoretical toolkit of both strands of literature does not match the task of coping analytically with structures and processes in the overlapping realm. To sharpen the analytical edge, the article elaborates hierarchy, market, community, and design as four ideal types of control modes in transnational regulatory spaces. The application of this model to the empirical analysis of a number of regimes underpins the observation that control frequently occurs in hybrid regulatory constellations involving public and private actors across national and international levels. A key example concerns the prominence of domestic regulatory regimes in underpinning transnational governance processes, where national rules achieve extraterritorial effect as much through competitive as through hierarchical mechanisms. [source]

,Asian values' as reverse Orientalism: Singapore

Michael Hill
It is possible to demonstrate, using Singapore as a key example, the way in which the attribution of a set of ,Asian values' represented a Western project which is best labelled ,reverse Orientalism'. This process entailed the attribution of a set of cultural values to East and Southeast Asian societies by Western social scientists in order to contrast the recent dynamic progress of Asian development with the stagnation and social disorganisation of contemporary Western economies and societies. The contrast provided legitimation for some of the nation-building policies of political leaders in such countries as Singapore and was incorporated in attempts to identify and institutionalise core values. [source]

Starting with complex primitives pays off: complicate locally, simplify globally

Aravind K. Joshi
Abstract In setting up a formal system to specify a grammar formalism, the conventional (mathematical) wisdom is to start with primitives (basic primitive structures) as simple as possible, and then introduce various operations for constructing more complex structures. An alternate approach is to start with complex (more complicated) primitives, which directly capture some crucial linguistic properties and then introduce some general operations for composing these complex structures. These two approaches provide different domains of locality, i.e., domains over which various types of linguistic dependencies can be specified. The latter approach, characterized as complicate locally, simplify globally (CLSG), pushes non-local dependencies to become local, i.e., they arise in the basic primitive structures to start with. The CLSG approach has led to some new insights into syntactic description, semantic composition, language generation, statistical processing, and psycholinguistic phenomena, all these with possible relevance to the cognitive architecture of language. In this paper, we will describe these results in an introductory manner making use of the framework of lexicalized tree-adjoining grammar (LTAG), a key example of the CLSG approach, thereby describing the interplay between formal analysis on the one hand and linguistic and processing issues on the other hand. [source]

The Versatility of Helicobacter pylori CagA Effector Protein Functions: The Master Key Hypothesis

HELICOBACTER, Issue 3 2010
Steffen Backert
Abstract Several bacterial pathogens inject virulence proteins into host target cells that are substrates of eukaryotic tyrosine kinases. One of the key examples is the Helicobacter pylori CagA effector protein which is translocated by a type-IV secretion system. Injected CagA becomes tyrosine-phosphorylated on EPIYA sequence motifs by Src and Abl family kinases. CagA then binds to and activates/inactivates multiple signaling proteins in a phosphorylation-dependent and phosphorylation-independent manner. A recent proteomic screen systematically identified eukaryotic binding partners of the EPIYA phosphorylation sites of CagA and similar sites in other bacterial effectors by high-resolution mass spectrometry. Individual phosphorylation sites recruited a surprisingly high number of interaction partners suggesting that each phosphorylation site can interfere with many downstream pathways. We now count 20 reported cellular binding partners of CagA, which represents the highest quantitiy among all yet known virulence-associated effector proteins in the microbial world. This complexity generates a highly remarkable and puzzling scenario. In addition, the first crystal structure of CagA provided us with new information on the function of this important virulence determinant. Here we review the recent advances in characterizing the multiple binding signaling activities of CagA. Injected CagA can act as a ,master key' that evolved the ability to highjack multiple host cell signalling cascades, which include the induction of membrane dynamics, actin-cytoskeletal rearrangements and the disruption of cell-to-cell junctions as well as proliferative, pro-inflammatory and anti-apoptotic nuclear responses. The discovery that different pathogens use this common strategy to subvert host cell functions suggests that more examples will emerge soon. [source]

Recent developments in the high-performance chelation ion chromatography of trace metals

Pavel N. Nesterenko
Abstract There have been a number of significant developments in the high-performance chelation ion chromatography (HPCIC) of trace metals in recent years. This review focuses on these developments, while giving important information on the fundamental parameters controlling the chelation sorption mechanism, including type of chelating group, stability constants, kinetics, and column temperature. The discussion pays particular attention to the types and properties of efficient chelating stationary phases which have been fabricated for certain groups of metals. The review also describes a number of major improvements in postcolumn reaction detection including the use of the latest reagents and noise reduction strategies to improve sensitivity and reduce LOD. In the final section, an indication of the applicability of HPCIC to a range of complex sample types is given with some key examples and chromatograms using the latest high-efficiency chelating phases. [source]

Unravelling response-specificity in Ca2+ signalling pathways in plant cells

Jason J. Rudd
Summary Considerable advances have been made, both in the technologies available to study changes in intracellular cytosolic free Ca2+ ([Ca2+]i), and in our understanding of Ca2+ signalling cascades in plant cells, but how specificity can be generated from such a ubiquitous component as Ca2+ is questionable. Recently the concept of ,Ca2+ signatures' has been formulated; tight control of the temporal and spatial characteristics of alterations in [Ca2+]i signals is thought to be responsible, at least in part, for the specificity of the response. However, the way in which Ca2+ signatures are decoded, which depends on the nature and location of the targets of the Ca2+ signals, has received little attention. In a few key systems, progress is being made on how diverse Ca2+ signatures might be transduced within cells in response to specific signals. Valuable pieces of the signal-specificity puzzle are being put together and this is illustrated here using some key examples; these emphasize the global importance of Ca2+ -mediated signal-transduction cascades in the responses of plants to a wide diversity of extracellular signals. However, the way in which signal specificity is encoded and transduced is still far from clear. [source]

Lentiviral vectors for treating and modeling human CNS disorders

Mimoun Azzouz
Abstract Vectors based on lentiviruses efficiently deliver genes into many different types of primary neurons from a broad range of species including man and the resulting gene expression is long term. These vectors are opening up new approaches for the treatment of neurological diseases such as Parkinson's disease (PD), Huntington's disease (HD), and motor neuron diseases (MNDs). Numerous animal studies have now been undertaken with these vectors and correction of disease models has been obtained. Lentiviral vectors also provide a new strategy for in vivo modeling of human diseases; for example, the lentiviral-mediated overexpression of mutated human ,-synuclein or huntingtin genes in basal ganglia induces neuronal pathology in animals resembling PD and HD in man. These vectors have been refined to a very high level and can be produced safely for the clinic. This review will describe the general features of lentiviral vectors with particular emphasis on vectors derived from the non-primate lentivirus, equine infectious anemia virus (EIAV). It will then describe some key examples of genetic correction and generation of genetic animal models of neurological diseases. The prospects for clinical application of lentiviral vectors for the treatment of PD and MNDs will also be outlined. Copyright © 2004 John Wiley & Sons, Ltd. [source]

Atmospheric pressure deposition of fluorine-doped SnO2 thin films from organotin fluorocarboxylate precursors

Mary F. Mahon
Abstract Nine organotin fluorocarboxylates RnSnO2CRf (n = 3, R = Bu, Rf = CF3, C2F5, C3F7, C7F15; R = Et, Rf = CF3, C2F5; R = Me, Rf = C2F5; n = 2, R = Me, Rf = CF3) have been synthesized; key examples have been used to deposit fluorine-doped SnO2 thin films by atmospheric pressure chemical vapour deposition. Et3SnO2CC2F5, in particular, gives high-quality films with fast deposition rates despite adopting a polymeric, carboxylate-bridged structure in the solid state, as determined by X-ray crystallography. Gas-phase electron diffraction on the model compound Me3SnO2CC2F5 shows that accessible conformations do not allow contact between tin and fluorine, and that direct transfer is therefore unlikely to be part of the mechanism for fluorine incorporation in SnO2 films. The structure of Me2Sn(O2CCF3)2(H2O) has also been determined and adopts a trans -Me2SnO3 coordination sphere about tin in which each carboxylate group is monodentate. Copyright © 2005 John Wiley & Sons, Ltd. [source]