902 resultados para Inducible Defence
Resumo:
The indolines and thionins are basic, amphiphilic and cysteine-rich proteins found in cereals; puroindoline-a (Pin-a) and β-purothionin (β-Pth) are members of these families in wheat (Triticum aestivum). Pin-a and β-Pth have been suggested to play a significant role in seed defence against microbial pathogens, making the interaction of these proteins with model bacterial membranes an area of potential interest. We have examined the binding of these proteins to lipid monolayers composed of 1,2-dipalmitoyl-sn-glycero-3-phospho-(1'-rac-glycerol) (DPPG) using a combination of neutron reflectometry, Brewster angle microscopy, and infrared spectroscopy. Results showed that both Pin-a and β-Pth interact strongly with condensed phase DPPG monolayers, but the degree of penetration was different. β-Pth was shown to penetrate the lipid acyl chain region of the monolayer and remove lipids from the air/liquid interface during the adsorption process, suggesting this protein may be able to both form membrane spanning ion channels and remove membrane phospholipids in its lytic activity. Conversely, Pin-a was shown to interact mainly with the head-group region of the condensed phase DPPG monolayer and form a 33 Å thick layer below the lipid film. The differences between the interfacial structures formed by these two proteins may be related to the differing composition of the Pin-a and β-Pth hydrophobic regions.
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This paper reviews recent research and other literature concerning the planning and development of redundant defence estate. It concentrates on UK sources but includes reference to material from Europe and the North America were it is relevant for comparative purposes. It introduces the topic by providing a brief review of the recent restructuring of the UK defence estate and then proceeds to examine the various planning policy issues generated by this process; the policy frameworks used to guide it; comparable approaches to surplus land disposal and the appraisal of impacts; and ending the main body of the review with an analyse of the economic, social and environmental impacts of military base closure and redevelopment. It concludes that there is a significant body of work focusing on the reuse and redevelopment of redundant defence estate in the UK and abroad, but that much of this work is based on limited research or on personal experience. One particular weakness of the current literature is that it does not fully reflect the institutional difficulties posed by the disposal process and the day-to-day pressures which MOD personnel have to deal with. In doing this, it also under-emphasises the embedded cultures of individuals and professional groups who are required to operationalise the policies, procedures and practices for planning and redeveloping redundant defence estate.
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Hydrogen sulfide (H(2)S) has recently been proposed as an endogenous mediator of inflammation and is present in human synovial fluid. This study determined whether primary human articular chondrocytes (HACs) and mesenchymal progenitor cells (MPCs) could synthesize H(2)S in response to pro-inflammatory cytokines relevant to human arthropathies, and to determine the cellular responses to endogenous and pharmacological H(2)S. HACs and MPCs were exposed to IL-1β, IL-6, TNF-α and lipopolysaccharide (LPS). The expression and enzymatic activity of the H(2)S synthesizing enzymes cystathionine-β-synthase (CBS) and cystathionine-γ-lyase (CSE) were determined by Western blot and zinc-trap spectrophotometry, respectively. Cellular oxidative stress was induced by H(2)O(2), the peroxynitrite donor SIN-1 and 4-hydroxynonenal (4-HNE). Cell death was assessed by 3-(4,5-dimethyl-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and lactate dehydrogenase (LDH) assays. Mitochondrial membrane potential (DCm) was determined in situ by flow cytometry. Endogenous H(2) S synthesis was inhibited by siRNA-mediated knockdown of CSE and CBS and pharmacological inhibitors D,L-propargylglycine and aminoxyacetate, respectively. Exogenous H(2)S was generated using GYY4137. Under basal conditions HACs and MPCs expressed CBS and CSE and synthesized H(2)S in a CBS-dependent manner, whereas CSE expression and activity was induced by treatment of cells with IL-1β, TNF-α, IL-6 or LPS. Oxidative stress-induced cell death was significantly inhibited by GYY4137 treatment but increased by pharmacological inhibition of H(2)S synthesis or by CBS/CSE-siRNA treatment. These data suggest CSE is an inducible source of H(2)S in cultured HACs and MPCs. H(2)S may represent a novel endogenous mechanism of cytoprotection in the inflamed joint, suggesting a potential opportunity for therapeutic intervention.
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Prostate cancer is one of the most frequent cancer types in Western societies and predominately occurs in the elderly male. The strong age-related increase of prostate cancer is associated with a progressive accumulation of oxidative DNA damage which is presumably supported by a decline of the cellular antioxidative defence during ageing. Risk of developing prostate cancer is much lower in many Asian countries where soy food is an integral part of diet. Therefore, isoflavones from soy were suggested to have chemopreventive activities in prostate cells. Here, we have investigated the hypothesis that the soy-isoflavone genistein could protect DNA of LAPC-4 prostate cells from oxidative stress-related damage by enhancing the expression of antioxidative genes and proteins. A 24 h preincubation with genistein (1-30 microM) protected cells from hydrogen peroxide-induced DNA damage, as determined by the comet assay. Analysis of two cDNA macroarrays, each containing 96 genes of biotransformation and stress response, revealed a modulated expression of 3 genes at 1 microM and of 19 genes at 10 microM genistein. Real-time PCR confirmed the induction of three genes encoding products with antioxidant activities, namely glutathione reductase (2.7-fold), microsomal glutathione S-transferase 1 (1.9-fold) and metallothionein 1X (6.3-fold), at 1-30 microM genistein. 17Beta-estradiol, in contrast, decreased the expression of metallothionein 1X at 0.3 microM (2.0-fold), possibly pointing to an estrogen receptor-mediated regulation of this gene. Immunocytochemical staining revealed an induction of metallothionein proteins at 30 microM genistein, while their intracellular localization was unaffected. Metallothioneins were previously found to protect cells from hydrogen peroxide-induced DNA damage. Hence, our findings indicate that genistein protects prostate cells from oxidative stress-related DNA damage presumably by inducing the expression of antioxidative products, such as metallothioneins. Genistein, therefore, might counteract the age-related decline of important antioxidative defence systems which in turn maintain DNA integrity.
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Ants are widely employed by plants as an antiherbivore defence. A single host plant can associate with multiple, symbiotic ant species, although usually only a single ant species at a time. Different plant-ant species may vary in the degree to which they defend their host plant. In Kenya, ant–acacia interactions are well studied, but less is known about systems elsewhere in Africa. A southern African species, Vachellia erioloba, is occupied by thorn-dwelling ants from three different genera. Unusually, multiple colonies of all these ants simultaneously and stably inhabit trees. We investigated if the ants on V. erioloba (i) deter insect herbivores; (ii) differ in their effectiveness depending on the identity of the herbivore; and (iii) protect the tree against an important herbivore, the larvae of the lepidopteran Gonometa postica. We show that experimental exclusion of ants leads to greater levels of herbivory on trees. The ants inhabiting V. erioloba are an effective deterrent against hemipteran and coleopteran, but not lepidopteran herbivores. Defensive services do not vary among ant species, but only Crematogaster ants exhibit aggression towards G. postica. This highlights the potential of the V. erioloba–ant mutualism for studying ant–plant interactions that involve multiple, simultaneously resident thorn-dwelling ant species.
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This article demonstrates how experiences of the same historical events (especially wars), but experienced from different angles, have led France and Germany to draw diametrically opposed lessons from them, which play key roles in the articulation of their defence postures and strategies.
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Review essay on recent literature on the transformation of European security politics in the 1980s
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This paper examines the implications of ‘cultural defence’ in the nature of democracy and the stability of the political system in Greece. It focuses on the Greek Orthodox Church’s maintenance of power and political relevance by virtue of its strong link to national identity. We argue that the inhibition of secularization in Greece as a result of cultural defence has significant policy implications, especially in times of crises, when the role of nationalism as a cohesive factor against perceived threats is intensified. The paper further explores three policy/politics areas: (1) political orientation; (2) religious pluralism; and (3) education.
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In order to bring conceptual clarity to a particular dimension of the relationship between the jus ad bellum and the jus in bello regimes, this article explores the independent sources of a military targeting rule in both branches of international law. The aim is not to displace the jus in bello as the ‘lead’ regime on how targeting decisions must be made, or to undermine the traditional separation between these regimes. Rather, conceptual light is shed on a sometimes assumed but generally neglected dimension of the jus ad bellum’s necessity and proportionality criteria that may, in limited circumstances, have significance for our understanding of human protection during war, by covering possible gaps in the jus in bello targeting rules.
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This article focuses on one particular factor that is of crucial importance to all self-defence actions. It is a factor that is almost always present in the application and appraisal of the right, but one that is not always explicitly engaged with: time. There are various ratione temporis elements underpinning the lawful exercise of the right of self-defence, and questions related to the timing of both an attack being responded to in self-defence and the response itself are notably controversial. The self-defence timeline is therefore charted, and the key legal debates encountered along its trajectory are identified. In particular, there is a focus on three temporal ‘stages’ of the right of self-defence: (i) the much-debated question of preventative forms of self-defence (the ‘before’); (ii) the timeliness of a state's defensive action, or what is sometimes called the need for the response to be ‘immediate’ (the ‘during’); and (iii) the duration of self-defence actions, including the crucial issue of when they must end (the ‘after’). The aim of this article is not to break new substantive ground with regard to these ‘stages’ as such, but is, rather, to draw together the temporal strands of self-defence in a more focused manner than is often the case in the literature.