902 resultados para inducible defence


Relevância:

10.00% 10.00%

Publicador:

Resumo:

Two preformed alk(en)ylresorcinols, 5-n-heptadecenylresorcinol and 5-n-pentadecylresorcinol, were identified in ‘Kensington Pride’ mango fruit peel. The alk(en)ylresorcinols had antifungal activity against C. gloeosporioides, as determined from thin layer chromatography bioassays. Soil-applied activators of plant defence (Acibenzolar at 150 mg L-1, and soluble potassium silicate at 200 and 1000 mg L-1) did not influence concentrations of 5-n-heptadecenylresorcinol or 5-n-pentadecyl¬resorcinol in mango peel when applied 2 months after fruit set and one month later. Concentrations of both alk(en)ylresorcinols were high 2 months after fruit set but levels declined by 50% within 1 month (2 months before commercial harvest) and did not change significantly from commercial harvest until eating-ripe.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Glucosinolates are a group of sulphur-containing glycosides found in the plant order Brassicales which includes the Brassica vegetables such as broccoli, cabbage and cauliflower. When brought into contact with the plant enzymes, myrosinases, the glucosinolates break down releasing glucose and other products which serve principally in plant defence against herbivores. The most important of the products from a human nutritional viewpoint, are the isothiocyanates. These potent inducers of detoxifying enzymes bestow the distinct anti-cancer properties on these plants. Unique among tropical fruits, papaya is known to contain an abundance of one particular glucosinolate, glucotropaeolin. Other compounds that play a pivotal role in the chemical defence system of many plants are the cyanogenic glycosides. Cyanogenic glycosides are activated by plant enzymes in the event of pest attack, releasing the deterrent: toxic hydrogen cyanide. Papaya, in addition to glucosinolates, also contains low levels of cyanogenic glycosides, an unusual occurrence because it was assumed that the two classes of metabolites were mutually exclusive. Studies measuring the levels of both in the edible parts of the papaya fruit and other utilised tissues are discussed and considered in the context of potential human health ramifications. All rights reserved, Elsevier.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Extreme vibration has been reported for small, high speed craft in the maritime sector, with performance and health threatening effects on boat operators and crew. Musculoskeletal injuries are an enduring problem for high speed craft passengers. Spinal or joint injuries and neurological disorders may occur from repetitive pounding over rough water, continued vibration and single impact events. The risk from whole body vibration (WBV) induced through the small vessels mainly depends on time spent on the craft, which can’t be changed in a military scenario; as well as the number of shocks and jolts, and their magnitude and frequency. In the European Union for example, physical agents directives require all employers to control exposure to a number of physical agents including noise and vibration. The EC Vibration Directive 2002/44/EC then sets out regulations for the control of health and safety risks from the exposure of workers to hand arm vibration (HAV) and WBV in the workplace. Australia has exposure standards relating to WBV, AS 2670.1-2001 – Evaluation of human exposure to whole body vibration. This standard is identical to the ISO 2631-1:1997, Mechanical vibration and shock – Evaluation of human exposure to whole-body vibration. Currently, none of the jurisdictions in Australia have specific regulations for vibration exposures in workplaces. However vibration is mentioned to varying degrees in their general regulations, codes of practice and guidance material. WBV on high speed craft is normally caused by “continuous 'hammering' from short steep seas or wind against tide conditions. Shock on High Speed Craft is usually caused by random impacts. Military organisations need the knowledge to make informed decisions regarding their marine operations, compliance with legislation and potentially harmful health effects, and develop and implement appropriate counter-measures. Marine case studies in the UK such as published MAIB (Marine Accident Investigation Branch) reports show injuries that have occurred in operation, and subsequent MCA (Maritime Coastguard Agency) guidance is provided (MGN 436 (M+F), WHOLE-BODY VIBRATION: Guidance on Mitigating Against the Effects of Shocks and Impacts on Small Vessels. MCA, 2011). This paper proposes a research framework to study the origin, impact and pathways for prevention of WBV in small, high speed craft in a maritime environment.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Background: Agriculture is facing enormous challenges to feed a growing population in the face of rapidly evolving pests and pathogens. The rusts, in particular, are a major pathogen of cereal crops with the potential to cause large reductions in yield. Improving stable disease resistance is an on-going major and challenging focus for many plant breeding programs, due to the rapidly evolving nature of the pathogen. Sorghum is a major summer cereal crop that is also a host for a rust pathogen which occurs in almost all sorghum growing areas of the world, causing direct and indirect yield losses in sorghum worldwide, however knowledge about its genetic control is still limited. In order to further investigate this issue, QTL and association mapping methods were implemented to study rust resistance in three bi-parental populations and an association mapping set of elite breeding lines in different environments. Results: In total, 64 significant or highly significant QTL and 21 suggestive rust resistance QTL were identified representing 55 unique genomic regions. Comparisons across populations within the current study and with rust QTL identified previously in both sorghum and maize revealed a high degree of correspondence in QTL location. Negative phenotypic correlations were observed between rust, maturity and height, indicating a trend for both early maturing and shorter genotypes to be more susceptible to rust. Conclusions: The significant amount of QTL co-location across traits, in addition to the consistency in the direction of QTL allele effects, has provided evidence to support pleiotropic QTL action across rust, height, maturity and stay-green, supporting the role of carbon stress in susceptibility to rust. Classical rust resistance QTL regions that did not co-locate with height, maturity or stay-green QTL were found to be significantly enriched for the defence-related NBS-encoding gene family, in contrast to the lack of defence-related gene enrichment in multi-trait effect rust resistance QTL. The distinction of disease resistance QTL hot-spots, enriched with defence-related gene families from QTL which impact on development and partitioning, provides plant breeders with knowledge which will allow for fast-tracking varieties with both durable pathogen resistance and appropriate adaptive traits.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Transgenic engineering of plants is important in both basic and applied research. However, the expression of a transgene can dwindle over time as the plant's small (s)RNA-guided silencing pathways shut it down. The silencing pathways have evolved as antiviral defence mechanisms, and viruses have co-evolved viral silencing-suppressor proteins (VSPs) to block them. Therefore, VSPs have been routinely used alongside desired transgene constructs to enhance their expression in transient assays. However, constitutive, stable expression of a VSP in a plant usually causes pronounced developmental abnormalities, as their actions interfere with endogenous microRNA-regulated processes, and has largely precluded the use of VSPs as an aid to stable transgene expression. In an attempt to avoid the deleterious effects but obtain the enhancing effect, a number of different VSPs were expressed exclusively in the seeds of Arabidopsis thaliana alongside a three-step transgenic pathway for the synthesis of arachidonic acid (AA), an ω-6 long chain polyunsaturated fatty acid. Results from independent transgenic events, maintained for four generations, showed that the VSP-AA-transformed plants were developmentally normal, apart from minor phenotypes at the cotyledon stage, and could produce 40% more AA than plants transformed with the AA transgene cassette alone. Intriguingly, a geminivirus VSP, V2, was constitutively expressed without causing developmental defects, as it acts on the siRNA amplification step that is not part of the miRNA pathway, and gave strong transgene enhancement. These results demonstrate that VSP expression can be used to protect and enhance stable transgene performance and has significant biotechnological application.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Brassica napus is one of the most important oil crops in the world, and stem rot caused by the fungus Sclerotinia sclerotiorum results in major losses in yield and quality. To elucidate resistance genes and pathogenesis-related genes, genome-wide association analysis of 347 accessions was performed using the Illumina 60K Brassica SNP (single nucleotide polymorphism) array. In addition, the detached stem inoculation assay was used to select five highly resistant (R) and susceptible (S) B. napus lines, 48 h postinoculation with S. sclerotiorum for transcriptome sequencing. We identified 17 significant associations for stem resistance on chromosomes A8 and C6, five of which were on A8 and 12 on C6. The SNPs identified on A8 were located in a 409-kb haplotype block, and those on C6 were consistent with previous QTL mapping efforts. Transcriptome analysis suggested that S. sclerotiorum infection activates the immune system, sulphur metabolism, especially glutathione (GSH) and glucosinolates in both R and S genotypes. Genes found to be specific to the R genotype related to the jasmonic acid pathway, lignin biosynthesis, defence response, signal transduction and encoding transcription factors. Twenty-four genes were identified in both the SNP-trait association and transcriptome sequencing analyses, including a tau class glutathione S-transferase (GSTU) gene cluster. This study provides useful insight into the molecular mechanisms underlying the plant's response to S. sclerotiorum.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Certain software products employing digital techniques for encryption of data are subject to export controls in the EU Member States pursuant to Community law and relevant laws in the Member States. These controls are agreed globally in the framework of the so-called Wassenaar Arrangement. Wassenaar is an informal non-proliferation regime aimed at promoting international stability and responsibility in transfers of strategic (dual-use) products and technology. This thesis covers provisions of Wassenaar, Community export control laws and export control laws of Finland, Sweden, Germany, France and United Kingdom. This thesis consists of five chapters. The first chapter discusses the ratio of export control laws and the impact they have on global trade. The ratio is originally defence-related - in general to prevent potential adversaries of participating States from having the same tools, and in particular in the case of cryptographic software to enable signals intelligence efforts. Increasingly as the use of cryptography in a civilian context has mushroomed, export restrictions can have negative effects on civilian trade. Information security solutions may also be took weak because of export restrictions on cryptography. The second chapter covers the OECD's Cryptography Policy, which had a significant effect on its member nations' national cryptography policies and legislation. The OECD is a significant organization,because it acts as a meeting forum for most important industrialized nations. The third chapter covers the Wassenaar Arrangement. The Arrangement is covered from the viewpoint of international law and politics. The Wassenaar control list provisions affecting cryptographic software transfers are also covered in detail. Control lists in the EU and in Member States are usually directly copied from Wassenaar control lists. Controls agreed in its framework set only a minimum level for participating States. However, Wassenaar countries can adopt stricter controls. The fourth chapter covers Community export control law. Export controls are viewed in Community law as falling within the domain of Common Commercial Policy pursuant to Article 133 of the EC Treaty. Therefore the Community has exclusive competence in export matters, save where a national measure is authorized by the Community or falls under foreign or security policy derogations established in Community law. The Member States still have a considerable amount of power in the domain of Common Foreign and Security Policy. They are able to maintain national export controls because export control laws are not fully harmonized. This can also have possible detrimental effects on the functioning of internal market and common export policies. In 1995 the EU adopted Dual-Use Regulation 3381/94/EC, which sets common rules for exports in Member States. Provisions of this regulation receive detailed coverage in this chapter. The fifth chapter covers national legislation and export authorization practices in five different Member States - in Finland, Sweden, Germany, France and in United Kingdom. Export control laws of those Member States are covered when the national laws differ from the uniform approach of the Community's acquis communautaire. Keywords: export control, encryption, software, dual-use, license, foreign trade, e-commerce, Internet

Relevância:

10.00% 10.00%

Publicador:

Resumo:

In this paper I conduct a Foucauldian discourse analysis of a political speech given by Brendon Nelson in 2006 when the Australian Minister for Defence in the Howard Coalition Government. The speech connects conceptualisations of terror, globalization, education and literacy as part of a whole of government security strategy. The analysis examines this speech as an example of a liberal way of governing the conduct of diverse and unpredictable populations. My analysis suggests that the apparatus of government has been strategically used in order to biopolitically contain the rise of complex social forces and protect a set of homogenous cultural values. The purposes of education and uses of literacy are seen as instruments for the inscription of a coded set of values understood to be synonymous with civil society.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

An inducible membrane-bound l-4-hydroxymandelate oxidase (decarboxylating) from Pseudomonas convexa has been solubilized and partially purified. It catalyzes the conversion of l-4-hydroxymandelic acid to 4-hydroxybenzaldehyde in a single step with the stoichiometric consumption of O2 and liberation of CO2. The enzyme is optimally active at pH 6.6 and at 55 oC. It requires FAD and Mn2+ for its activity. The membrane-bound enzyme is more stable than the solubilized and purified enzyme. After solubilization it gradually loses its activity when kept at 5 oC which can be fully reactivated by freezing and thawing. The Km values for DL-4-hydroxymandelate and FAD are 0.44 mM and 0.038 mM respectively. The enzyme is highly specific for DL-4-hydroxymandelic acid. DL-3,4-Dihydroxymandelic acid competitively inhibited the enzyme reaction. From the Dixon plot the Ki for DL-3,4-dihydroxymandelic acid was calculated to be 1.8 × 10−4 M. The enzyme is completely inactivated by thiol compounds and not affected by thiol inhibitors. The enzyme is also inhibited by denaturing agents, heavy metal ions and by chelating agents.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

An inducible Image -mandelate-4-hydroxylase has been partially purified from crude extracts of Pseudomonas convexa. This enzyme catalyzed the hydroxylation of Image -mandelic acid to 4-hydroxymandelic acid. It required tetrahydropteridine, NADPH, Fe2+, and O2 for its activity. The approximate molecular weight of the enzyme was assessed as 91,000 by gel filtration on Sephadex G-150. The enzyme was optimally active at pH 5.4 and 38 °C. A classical Michaelis-Menten kinetic pattern was observed with Image -mandelate, NADPH, and ferrous sulfate and Km values for these substrates were found to be 1 × 10−4, 1.9 × 10−4, and 4.7 × 10−5 Image , respectively. The enzyme is very specific for Image -mandelate as substrate. Thiol inhibitors inhibited the enzyme reaction, indicating that the sulfhydryl groups may be essential for the enzyme action. Treatment of the partially purified enzyme with denaturing agents inactivated the enzyme.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

This dissertation is a study of some aspects of theoretical philosophy of the early modern thinker Thomas Hobbes (1588-1679). The focal point of the work is Hobbes s conception of imagination, which is discussed from both a systematic and a historical point of view, as well as in the light of contemporary scholarship. I argue that though there are significant similarities between the view of Hobbes and that of his predecessors, he gives a novel theory of imagination, which clarifies not only early modern discussions on human nature, knowledge, science, and literary criticism, but above all his own versatile philosophy. The prologue of the dissertation introduces methodological principles and gives critical remarks on the standard view of Hobbes. In Chapter II, I discuss the prominent theories of imagination before Hobbes and link them to his account. I argue that though Hobbes adopted the Aristotelian framework, his view is not reduced to it, as he borrows from various sources, for instance, from the Stoics and from Renaissance thought. Chapters III and IV form the psychological part of the work. In the Chapter III I argue that imagination, not sense, is central in the basic cognitive operations of the mind and that imagination has a decisive role in Hobbes s theory of motivation. The Chapter IV concentrates on various questions of Hobbes s philosophy of language. The chapter ends with a defence of a less naturalistic reading of Hobbes s theory of human nature. Chapters V and VI form the epistemological part of the work. I suggest, contrary to what has been recently claimed, that though Hobbes s ideas of good literary style do have a point of contact with his philosophy (e.g. the psychology of creative process), his ideas in the field are independent of his project of demonstrative political science. Instead I argue that the novelty of his major political work, Leviathan (1651), is based on a new theory of knowledge which he continued to develop in the post-Leviathan works. Chapter VII seeks to connect the more theoretical conclusions of Chapters V and VI to Hobbes's idea(l) of science as well as to his philosophical practice. On the basis of Hobbes s own writings as well as some historical examinations, I argue that method is not an apt way to conceptualise Hobbes s philosophical practice. Contemporary readings of Hobbes s theory of science are critically discussed and the chapter ends with an analysis of Hobbes s actual argumentation. In addition to the concluding remarks, the epilogue suggest three things: first, imagination is central when trying to understand Hobbes s versatile philosophy; second, that it is misleading to depict Hobbes as a simple materialist, mechanist, and empiricist; and, third, that in terms of imagination his influence on early modern thought has not been fully appreciated.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

An inducible benzoate-4-hydroxylase has been partially purified from crude extracts of the mycelial felts of Aspergillus niger. This enzyme catalyzes the transformation of benzoate to p-hydroxybenzoate with equimolar consumption of NADPH and O2. It requires tetrahydropteridine as a prosthetic group. The optimum activity was found at pH 6.2 with a Km value at 30°C of 1.6 · 10−4 M for NADPH and 1.3 · 10−4 M for benzoate. Fe2+ (iron) is required for the enzyme activity. The enzyme is stabilized by the inclusion of benzoate, EDTA and glutathione in the extracting buffer. The enzyme is specific for benzoate as substrate. Sulfhydryl group(s) are essential for enzyme activity as indicated by p-chloromercuri-benzoate and N-ethylmaleimide inactivation. Benzoate-4-hydroxylase activity is decreased in the mycelial felts of Aspergillus niger grown in the presence of higher concentrations of benzoate. Maximum activity of the enzyme was observed at 36 h after inoculation.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Co-stimulatory signals are essential for the activation of naïve T cells and productive immune response. Naïve T cells receive first, antigen-specific signal through T cell receptor. Co-stimulatory receptors provide the second signal which can be either activating or inhibitory. The balance between signals determines the outcome of an immune response. CD28 is crucial for T cell activation; whereas cytotoxic T lymphocyte associated antigen 4 (CTLA4) mediates critical inhibitory signal. Inducible co-stimulator (ICOS) augments cytokine expression and plays role in immunoglobulin class switching. Programmed cell death 1 (PDCD1) acts as negative regulator of T cell proliferation and cytokine responses. The co-stimulatory receptor pathways are potentially involved in self-tolerance and thus, they provide a promising therapeutic strategy for autoimmune diseases and transplantation. The genes encoding CD28, CTLA4 and ICOS are located adjacently in the chromosome region 2q33. The PDCD1 gene maps further, to the region 2q37. CTLA4 and PDCD1 are associated with the risk of a few autoimmune diseases. There is strong linkage disequilibrium (LD) on the 2q33 region; the whole gene of CD28 exists in its own LD block but CTLA4 and the 5' part of ICOS are within a same LD block. The 3' part of ICOS and PDCD1 are in their own separate LD blocks. Extended haplotypes covering the 2q33 region can be identified. This study focuses on immune related conditions like coeliac disease (CD) which is a chronic inflammatory disease with autoimmune features. Immunoglobulin A deficiency (IgAD) belongs to the group of primary antibody deficiencies characterised by reduced levels of immunoglobulins. IgAD co-occurs often with coeliac disease. Renal transplantation is needed in the end stage kidney diseases. Transplantation causes strong immune response which is tried to suppress with drugs. All these conditions are multifactorial with complex genetic background and multiple environmental factors affecting the outcome. We have screened ICOS for polymorphisms by sequencing the exon regions. We detected 11 new variants and determined their frequencies in Finnish population. We have measured linkage disequilibrium on the 2q33 region in Finnish as well as other European populations and observed conserved haplotypes. We analysed genetic association and linkage of the co-stimulatory receptor gene region aiming to study if it is a common risk locus for immune diseases. The 2q33 region was replicated to be linked to coeliac disease in Finnish population and CTLA4-ICOS haplotypes were found to be associated with CD and IgAD being the first non-HLA risk locus common for CD and immunodeficiencies. We also showed association between ICOS and the outcome of kidney transplantation. Our results suggest new evidence for CTLA4-ICOS gene region to be involved in susceptibility of coeliac disease. The earlier published contradictory association results can be explained by involvement of both CTLA4 and ICOS in disease susceptibility. The pattern of variants acting together rather than a single polymorphism may confer the disease risk. These genes may predispose also to immunodeficiencies as well as decreased graft survival and delayed graft function. Consequently, the present study indicates that like the well established HLA locus, the co-stimulatory receptor genes predispose to variety of immune disorders.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Plasma membrane adopts myriad of different shapes to carry out essential cellular processes such as nutrient uptake, immunological defence mechanisms and cell migration. Therefore, the details how different plasma membrane structures are made and remodelled are of the upmost importance. Bending of plasma membrane into different shapes requires substantial amount of force, which can be provided by the actin cytoskeleton, however, the molecules that regulate the interplay between the actin cytoskeleton and plasma membrane have remained elusive. Recent findings have placed new types of effectors at sites of plasma membrane remodelling, including BAR proteins, which can directly bind and deform plasma membrane into different shapes. In addition to their membrane-bending abilities, BAR proteins also harbor protein domains that intimately link them to the actin cytoskeleton. The ancient BAR domain fold has evolved into at least three structurally and functionally different sub-groups: the BAR, F-BAR and I-BAR domains. This thesis work describes the discovery and functional characterization of the Inverse-BAR domains (I-BARs). Using synthetic model membranes, we have shown that I-BAR domains bind and deform membranes into tubular structures through a binding-surface composed of positively charged amino acids. Importantly, the membrane-binding surface of I-BAR domains displays an inverse geometry to that of the BAR and F-BAR domains, and these structural differences explain why I-BAR domains induce cell protrusions whereas BAR and most F-BAR domains induce cell invaginations. In addition, our results indicate that the binding of I-BAR domains to membranes can alter the spatial organization of phosphoinositides within membranes. Intriguingly, we also found that some I-BAR domains can insert helical motifs into the membrane bilayer, which has important consequences for their membrane binding/bending functions. In mammals there are five I-BAR domain containing proteins. Cell biological studies on ABBA revealed that it is highly expressed in radial glial cells during the development of the central nervous system and plays an important role in the extension process of radial glia-like C6R cells by regulating lamellipodial dynamics through its I-BAR domain. To reveal the role of these proteins in the context of animals, we analyzed MIM knockout mice and found that MIM is required for proper renal functions in adult mice. MIM deficient mice displayed a severe urine concentration defect due to defective intercellular junctions of the kidney epithelia. Consistently, MIM localized to adherens junctions in cultured kidney epithelial cells, where it promoted actin assembly through its I-BAR andWH2 domains. In summary, this thesis describes the mechanism how I-BAR proteins deform membranes and provides information about the biological role of these proteins, which to our knowledge are the first proteins that have been shown to directly deform plasma membrane to make cell protrusions.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

This report shares findings and insights from an interview study conducted in 2009, with 34 ADF families. These families were identified in the communities of primary schools in both state and Catholic systems with high ADF family enrolments in 3 towns across 2 states, with the assistance of the DCO and their embedded Defence School Transition Aides (DSTAs). In the interviews the parents were invited to describe their history of ADF relocations, and how they managed transitions for each member in terms of school choice, child care arrangements, spouse employment, and educational transitions. Parallel interviews were conducted with 12 teachers and 6 DSTAs across the identified schools to describe how schools cater for mobile ADF families flowing through their classes. Parents were invited to tell the story of their family’s sequence of moves and how each member made the transition, then reflect more generally on what advice they’d give other mobile families. Teachers were asked to describe how they respond to the mobile families in their school community, and to illustrate some of the issues and challenges from the institutional perspective. By offering perspectives from both parents and teachers, the report hopes to facilitate a dialogue between parties to address their common goal – promoting productive continuities in education for children in mobile families.