WorldWideScience

Sample records for host defence signaling

  1. Host defences against Giardia lamblia.

    Science.gov (United States)

    Lopez-Romero, G; Quintero, J; Astiazarán-García, H; Velazquez, C

    2015-08-01

    Giardia spp. is a protozoan parasite that inhabits the upper small intestine of mammals and other species and is the aetiological agent of giardiasis. It has been demonstrated that nitric oxide, mast cells and dendritic cells are the first line of defence against Giardia. IL-6 and IL-17 play an important role during infection. Several cytokines possess overlapping functions in regulating innate and adaptive immune responses. IgA and CD4(+) T cells are fundamental to the process of Giardia clearance. It has been suggested that CD4(+) T cells play a double role during the anti-Giardia immune response. First, they activate and stimulate the differentiation of B cells to generate Giardia-specific antibodies. Second, they act through a B-cell-independent mechanism that is probably mediated by Th17 cells. Several Giardia proteins that stimulate humoral and cellular immune responses have been described. Variant surface proteins, α-1 giardin, and cyst wall protein 2 can induce host protective responses to future Giardia challenges. The characterization and evaluation of the protective potential of the immunogenic proteins that are associated with Giardia will offer new insights into host-parasite interactions and may aid in the development of an effective vaccine against the parasite. © 2015 John Wiley & Sons Ltd.

  2. Host Defence to Pulmonary Mycosis

    Directory of Open Access Journals (Sweden)

    Christopher H Mody

    1999-01-01

    Full Text Available OBJECTIVE: To provide a basic understanding of the mechanisms of host defense to pathogenic fungi. This will help physicians understand why some patients are predisposed to fungal infections and update basic scientists on how microbial immunology applies to fungal disease.

  3. Plants under attack: systemic signals in defence.

    Science.gov (United States)

    Shah, Jyoti

    2009-08-01

    Efficient communication between the pest-colonised and non-colonised organs is vital for the timely manifestation of defences that restrict systemic spread of pests. The vasculature provides an important conduit for translocation of signals that contribute to long-distance communication within a plant. Airborne signals also contribute to this process. In recent years, major advances have been made in identifying metabolites that are candidate systemic signals in plant defence against pathogens. Methyl salicylate, jasmonates, azelaic acid and a diterpenoid have been implicated as mobile signals associated with the activation of systemic acquired resistance (SAR), which confers enhanced resistance against a broad spectrum of pathogens. By contrast, auxins probably contribute to negative regulation of systemic defences.

  4. MAPK cascade signalling networks in plant defence.

    Science.gov (United States)

    Pitzschke, Andrea; Schikora, Adam; Hirt, Heribert

    2009-08-01

    The sensing of stress signals and their transduction into appropriate responses is crucial for the adaptation and survival of plants. Kinase cascades of the mitogen-activated protein kinase (MAPK) class play a remarkably important role in plant signalling of a variety of abiotic and biotic stresses. MAPK cascade-mediated signalling is an essential step in the establishment of resistance to pathogens. Here, we describe the most recent insights into MAPK-mediated pathogen defence response regulation with a particular focus on the cascades involving MPK3, MPK4 and MPK6. We also discuss the strategies developed by plant pathogens to circumvent, inactivate or even 'hijack' MAPK-mediated defence responses.

  5. Shaping Baltic States Defence Strategy: Host Nation Support

    Directory of Open Access Journals (Sweden)

    Otzulis Valdis

    2017-12-01

    Full Text Available The presence of NATO troops in the Baltic states has increased in the last years due to changing international environment, increased level of potential risks and threats, and necessity to enhance deterrence in the region. As a result of NATO’s Wales and Warsaw summits decisions, Estonia, Latvia, and Lithuania are entitled to host a battalion size battle group. The article aims at investigating how host nation support (HNS can contribute to the national defence and, additionally, to the self-defence capabilities of the Baltic states. The concept of HNS is present in the national defence concepts of all three countries. However, its active application and utilization started in the last two years. The article argues that more intensive incorporation of an HNS system in national defence policies serve the capability development in fields like national military logistics, infrastructure, and civil-military cooperation. Those capabilities can serve as an extension of the national defence.

  6. Leaf Colour as a Signal of Chemical Defence to Insect Herbivores in Wild Cabbage (Brassica oleracea).

    Science.gov (United States)

    Green, Jonathan P; Foster, Rosie; Wilkins, Lucas; Osorio, Daniel; Hartley, Susan E

    2015-01-01

    Leaf colour has been proposed to signal levels of host defence to insect herbivores, but we lack data on herbivory, leaf colour and levels of defence for wild host populations necessary to test this hypothesis. Such a test requires measurements of leaf spectra as they would be sensed by herbivore visual systems, as well as simultaneous measurements of chemical defences and herbivore responses to leaf colour in natural host-herbivore populations. In a large-scale field survey of wild cabbage (Brassica oleracea) populations, we show that variation in leaf colour and brightness, measured according to herbivore spectral sensitivities, predicts both levels of chemical defences (glucosinolates) and abundance of specialist lepidopteran (Pieris rapae) and hemipteran (Brevicoryne brassicae) herbivores. In subsequent experiments, P. rapae larvae achieved faster growth and greater pupal mass when feeding on plants with bluer leaves, which contained lower levels of aliphatic glucosinolates. Glucosinolate-mediated effects on larval performance may thus contribute to the association between P. rapae herbivory and leaf colour observed in the field. However, preference tests found no evidence that adult butterflies selected host plants based on leaf coloration. In the field, B. brassicae abundance varied with leaf brightness but greenhouse experiments were unable to identify any effects of brightness on aphid preference or performance. Our findings suggest that although leaf colour reflects both levels of host defences and herbivore abundance in the field, the ability of herbivores to respond to colour signals may be limited, even in species where performance is correlated with leaf colour.

  7. The vaginal microbiota, host defence and reproductive physiology.

    Science.gov (United States)

    Smith, Steven B; Ravel, Jacques

    2017-01-15

    The interaction between the human host and the vaginal microbiota is highly dynamic. Major changes in the vaginal physiology and microbiota over a woman's lifetime are largely shaped by transitional periods such as puberty, menopause and pregnancy, while daily fluctuations in microbial composition observed through culture-independent studies are more likely to be the results of daily life activities and behaviours. The vaginal microbiota of reproductive-aged women is largely made up of at least five different community state types. Four of these community state types are dominated by lactic-acid producing Lactobacillus spp. while the fifth is commonly composed of anaerobes and strict anaerobes and is sometimes associated with vaginal symptoms. The production of lactic acid has been associated with contributing to the overall health of the vagina due to its direct and indirect effects on pathogens and host defence. Some species associated with non-Lactobacillus vaginal microbiota may trigger immune responses as well as degrade the host mucosa, processes that ultimately increase susceptibility to infections and contribute to negative reproductive outcomes such as infertility and preterm birth. Further studies are needed to better understand the functional underpinnings of how the vaginal microbiota affect host physiology but also how host physiology affects the vaginal microbiota. Understanding this fine-tuned interaction is key to maintaining women's reproductive health. © 2016 The Authors. The Journal of Physiology © 2016 The Physiological Society.

  8. The regulation of host defences to infection by the microbiota.

    Science.gov (United States)

    Brown, Rebecca L; Clarke, Thomas B

    2017-01-01

    The skin and mucosal epithelia of humans and other mammals are permanently colonized by large microbial communities (the microbiota). Due to this life-long association with the microbiota, these microbes have an extensive influence over the physiology of their host organism. It is now becoming apparent that nearly all tissues and organ systems, whether in direct contact with the microbiota or in deeper host sites, are under microbial influence. The immune system is perhaps the most profoundly affected, with the microbiota programming both its innate and adaptive arms. The regulation of immunity by the microbiota helps to protect the host against intestinal and extra-intestinal infection by many classes of pathogen. In this review, we will discuss the experimental evidence supporting a role for the microbiota in regulating host defences to extra-intestinal infection, draw together common mechanistic themes, including the central role of pattern recognition receptors, and outline outstanding questions that need to be answered. © 2016 The Authors. Immunology Published by John Wiley & Sons Ltd.

  9. Collective defence portfolios of ant hosts shift with social parasite pressure.

    Science.gov (United States)

    Jongepier, Evelien; Kleeberg, Isabelle; Job, Sylwester; Foitzik, Susanne

    2014-09-22

    Host defences become increasingly costly as parasites breach successive lines of defence. Because selection favours hosts that successfully resist parasitism at the lowest possible cost, escalating coevolutionary arms races are likely to drive host defence portfolios towards ever more expensive strategies. We investigated the interplay between host defence portfolios and social parasite pressure by comparing 17 populations of two Temnothorax ant species. When successful, collective aggression not only prevents parasitation but also spares host colonies the cost of searching for and moving to a new nest site. However, once parasites breach the host's nest defence, host colonies should resort to flight as the more beneficial resistance strategy. We show that under low parasite pressure, host colonies more likely responded to an intruding Protomognathus americanus slavemaker with collective aggression, which prevented the slavemaker from escaping and potentially recruiting nest-mates. However, as parasite pressure increased, ant colonies of both host species became more likely to flee rather than to fight. We conclude that host defence portfolios shift consistently with social parasite pressure, which is in accordance with the degeneration of frontline defences and the evolution of subsequent anti-parasite strategies often invoked in hosts of brood parasites. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

  10. Role of the dual interaction of fungal pathogens with pattern recognition receptors in the activation and modulation of host defence.

    NARCIS (Netherlands)

    Netea, M.G.; Meer, J.W.M. van der; Kullberg, B.J.

    2006-01-01

    Recognition of pathogen-associated molecular patterns (PAMPs) of microorganisms by pathogen recognition receptors induces signals responsible for the activation of genes important for an effective host defence, especially those of pro-inflammatory cytokines. Toll-like receptors (TLRs) and

  11. Signalling network construction for modelling plant defence response.

    Directory of Open Access Journals (Sweden)

    Dragana Miljkovic

    Full Text Available Plant defence signalling response against various pathogens, including viruses, is a complex phenomenon. In resistant interaction a plant cell perceives the pathogen signal, transduces it within the cell and performs a reprogramming of the cell metabolism leading to the pathogen replication arrest. This work focuses on signalling pathways crucial for the plant defence response, i.e., the salicylic acid, jasmonic acid and ethylene signal transduction pathways, in the Arabidopsis thaliana model plant. The initial signalling network topology was constructed manually by defining the representation formalism, encoding the information from public databases and literature, and composing a pathway diagram. The manually constructed network structure consists of 175 components and 387 reactions. In order to complement the network topology with possibly missing relations, a new approach to automated information extraction from biological literature was developed. This approach, named Bio3graph, allows for automated extraction of biological relations from the literature, resulting in a set of (component1, reaction, component2 triplets and composing a graph structure which can be visualised, compared to the manually constructed topology and examined by the experts. Using a plant defence response vocabulary of components and reaction types, Bio3graph was applied to a set of 9,586 relevant full text articles, resulting in 137 newly detected reactions between the components. Finally, the manually constructed topology and the new reactions were merged to form a network structure consisting of 175 components and 524 reactions. The resulting pathway diagram of plant defence signalling represents a valuable source for further computational modelling and interpretation of omics data. The developed Bio3graph approach, implemented as an executable language processing and graph visualisation workflow, is publically available at http://ropot.ijs.si/bio3graph/and can be

  12. The cytoskeleton in cell-autonomous immunity: structural determinants of host defence

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    Mostowy, Serge; Shenoy, Avinash R.

    2016-01-01

    Host cells use antimicrobial proteins, pathogen-restrictive compartmentalization and cell death in their defence against intracellular pathogens. Recent work has revealed that four components of the cytoskeleton — actin, microtubules, intermediate filaments and septins, which are well known for their roles in cell division, shape and movement — have important functions in innate immunity and cellular self-defence. Investigations using cellular and animal models have shown that these cytoskeletal proteins are crucial for sensing bacteria and for mobilizing effector mechanisms to eliminate them. In this Review, we highlight the emerging roles of the cytoskeleton as a structural determinant of cell-autonomous host defence. PMID:26292640

  13. Evolution of host innate defence: insights from Caenorhabditis elegans and primitive invertebrates.

    Science.gov (United States)

    Irazoqui, Javier E; Urbach, Jonathan M; Ausubel, Frederick M

    2010-01-01

    The genetically tractable model organism Caenorhabditis elegans was first used to model bacterial virulence in vivo a decade ago. Since then, great strides have been made in identifying the host response pathways that are involved in its defence against infection. Strikingly, C. elegans seems to detect, and respond to, infection without the involvement of its homologue of Toll-like receptors, in contrast to the well-established role for these proteins in innate immunity in mammals. What, therefore, do we know about host defence mechanisms in C. elegans and what can they tell us about innate immunity in higher organisms?

  14. Evolution of host innate defence: insights from C. elegans and primitive invertebrates

    Science.gov (United States)

    Irazoqui, Javier E.; Urbach, Jonathan M.; Ausubel, Frederick M.

    2010-01-01

    Preface The genetically tractable model organism Caenorhabditis elegans was first used to model bacterial virulence in vivo a decade ago. Since then, great strides have been made in the identification of host response pathways that are involved in the defence against infection. Strikingly, C. elegans seems to detect and respond to infection without the involvement of its Toll-like receptor homologue, in contrast to the well-established role for these proteins in innate immunity in mammals. What, therefore, do we know about host defence mechanisms in C. elegans, and what can they tell us about innate immunity in higher organisms? PMID:20029447

  15. In Vitro Activities against Cystic Fibrosis Pathogens of Synthetic Host Defence Propeptides Processed by Neutrophil Elastase.

    LENUS (Irish Health Repository)

    Desgranges, Stephane

    2011-02-22

    The antimicrobial and haemolytic activities of a host defence peptide can be controlled by modification as a propeptide of reduced net charge which can be processed by neutrophil elastase, a serine protease involved in chronic airway inflammation and infections associated with cystic fibrosis.

  16. Quorum-Sensing Blockade As A Strategy for Enhancing Host Defences Against Bacterial Pathogens

    DEFF Research Database (Denmark)

    Bjarnsholt, Thomas; Givskov, Michael Christian

    2007-01-01

    rise to a new 'drug target rush'. Recently, QS has been shown to be involved in the development of tolerance to various antimicrobial treatments and immune modulation. The regulation of virulence via QS confers a strategic advantage over host defences. Consequently, a drug capable of blocking QS...

  17. Quorum-sensing blockade as a strategy for enhancing host defences against bacterial pathogens

    DEFF Research Database (Denmark)

    Bjarnsholt, Thomas; Givskov, Michael Christian

    2007-01-01

    rise to a new 'drug target rush'. Recently, QS has been shown to be involved in the development of tolerance to various antimicrobial treatments and immune modulation. The regulation of virulence via QS confers a strategic advantage over host defences. Consequently, a drug capable of blocking QS...

  18. Optimal immunity meets natural variation: the evolutionary biology of host defence.

    Science.gov (United States)

    Graham, A L

    2013-11-01

    This editorial introduces the seven articles that comprise the Parasite Immunology special issue on the Evolutionary Biology of Host Defence. The rationale for an evolutionary approach to immunoparasitology is briefly outlined, and then the articles are placed in that broader context. A central aim of each article is to explain the generation and maintenance of immunological heterogeneity among hosts in nature. The authors describe new tools and approaches that enable unprecedented insight into evolutionary and immunological processes in both the laboratory and the wild. The examples discussed include insects, birds and mammals (as hosts) and trypanosomes, apicomplexans and nematodes (as parasites). © 2013 John Wiley & Sons Ltd.

  19. A SNARE-protein has opposing functions in penetration resistance and defence signalling pathways

    DEFF Research Database (Denmark)

    Zhang, Ziguo; Feechan, Angela; Pedersen, Carsten

    2007-01-01

    Penetration resistance is often the first line of defence against fungal pathogens. Subsequently induced defences are mediated by the programmed cell death (PCD) reaction pathway and the salicylic acid (SA), jasmonic acid (JA) and ethylene (ET) signalling pathways. We previously demonstrated...

  20. Tick salivary compounds: their role in modulation of host defences and pathogen transmission

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    Kazimírová, Mária; Štibrániová, Iveta

    2013-01-01

    Ticks require blood meal to complete development and reproduction. Multifunctional tick salivary glands play a pivotal role in tick feeding and transmission of pathogens. Tick salivary molecules injected into the host modulate host defence responses to the benefit of the feeding ticks. To colonize tick organs, tick-borne microorganisms must overcome several barriers, i.e., tick gut membrane, tick immunity, and moulting. Tick-borne pathogens co-evolved with their vectors and hosts and developed molecular adaptations to avoid adverse effects of tick and host defences. Large gaps exist in the knowledge of survival strategies of tick-borne microorganisms and on the molecular mechanisms of tick-host-pathogen interactions. Prior to transmission to a host, the microorganisms penetrate and multiply in tick salivary glands. As soon as the tick is attached to a host, gene expression and production of salivary molecules is upregulated, primarily to facilitate feeding and avoid tick rejection by the host. Pathogens exploit tick salivary molecules for their survival and multiplication in the vector and transmission to and establishment in the hosts. Promotion of pathogen transmission by bioactive molecules in tick saliva was described as saliva-assisted transmission (SAT). SAT candidates comprise compounds with anti-haemostatic, anti-inflammatory and immunomodulatory functions, but the molecular mechanisms by which they mediate pathogen transmission are largely unknown. To date only a few tick salivary molecules associated with specific pathogen transmission have been identified and their functions partially elucidated. Advanced molecular techniques are applied in studying tick-host-pathogen interactions and provide information on expression of vector and pathogen genes during pathogen acquisition, establishment and transmission. Understanding the molecular events on the tick-host-pathogen interface may lead to development of new strategies to control tick-borne diseases. PMID

  1. Cross-talk between plant defence signalling pathways: boost or burden?

    NARCIS (Netherlands)

    Pieterse, C.M.J.; Ton, J.; Loon, L.C. van

    2001-01-01

    Plants are exposed to very different attackers, including microbial pathogens and herbivorous insects. To protect themselves, plants have evolved defensive strategies to counteract potential invaders. Recent advances in plant defence signalling research have revealed that plants are capable of

  2. Activation of host constitutive immune defence by an intestinal trypanosome parasite of bumble bees.

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    Brown, M J F; Moret, Y; Schmid-Hempel, P

    2003-03-01

    Many parasites, including important species that affect humans and livestock, must survive the harsh environment of insect guts to complete their life-cycle. Hence, understanding how insects protect themselves against such parasites has immediate practical implications. Previously, such protection has been thought to consist mainly of mechanical structures and the action of lectins. However, recently it has become apparent that gut infections may interact with the host immune system in more complex ways. Here, using bumble bees, Bombus terrestris and their non-invasive gut trypanosome, Crithidia bombi, as a model system we investigated the effects of parasitic infection, host resources and the duration of infections on the host immune system. We found that infection doubled standing levels of immune defence in the haemolymph (the constitutive pro-phenoloxidase system), which is used as a first, general defence against parasites. However, physical separation of the parasite from the haemolymph suggests the presence of a messenger system between the gut and the genes that control the pro-phenoloxidase system. Surprisingly, we found no direct effect of host resource-stress or duration of the infection on the immune system. Our results suggest a novel and tactical response of insects to gut infections, demonstrating the complexity of such host-parasite systems.

  3. Combining personal with social information facilitates host defences and explains why cuckoos should be secretive

    Science.gov (United States)

    Thorogood, Rose; Davies, Nicholas B.

    2016-01-01

    Individuals often vary defences in response to local predation or parasitism risk. But how should they assess threat levels when it pays their enemies to hide? For common cuckoo hosts, assessing parasitism risk is challenging: cuckoo eggs are mimetic and adult cuckoos are secretive and resemble hawks. Here, we show that egg rejection by reed warblers depends on combining personal and social information of local risk. We presented model cuckoos or controls at a pair’s own nest (personal information of an intruder) and/or on a neighbouring territory, to which they were attracted by broadcasts of alarm calls (social information). Rejection of an experimental egg was stimulated only when hosts were alerted by both social and personal information of cuckoos. However, pairs that rejected eggs were not more likely to mob a cuckoo. Therefore, while hosts can assess risk from the sight of a cuckoo, a cuckoo cannot gauge if her egg will be accepted from host mobbing. Our results reveal how hosts respond rapidly to local variation in parasitism, and why it pays cuckoos to be secretive, both to avoid alerting their targets and to limit the spread of social information in the local host neighbourhood. PMID:26794435

  4. Training innate immunity: the changing concept of immunological memory in innate host defence.

    Science.gov (United States)

    Netea, Mihai G

    2013-08-01

    The inability of innate immunity to build an immunological memory is considered a main difference with adaptive immunity. This concept has been challenged by studies in plants, invertebrates and mammals. Recently, a paradigm shift in our understanding host defence has been triggered by the mounting evidence for innate immune memory, leading to increased responses to secondary infections. Important differences between the cell populations and the molecular mechanisms exist between the adaptive traits of innate host defence on the one hand and immunological memory of adaptive immunity on the other hand. The lasting state of enhanced innate immunity termed 'trained immunity' is mediated by prototypical innate immune cells such as natural killer cells and monocytes/macrophages. It provides protection against reinfection in a T/B-cell-independent manner, with both specific mechanisms and nonspecific epigenetic reprogramming mediating these effects. This concept represents a paradigm change in immunity, and its putative role in resistance to reinfection may represent the next step in the design of future vaccines. © 2013 Stichting European Society for Clinical Investigation Journal Foundation. Published by John Wiley & Sons Ltd.

  5. The Xanthomonas campestris type III effector XopJ targets the host cell proteasome to suppress salicylic-acid mediated plant defence.

    Directory of Open Access Journals (Sweden)

    Suayib Üstün

    Full Text Available The phytopathogenic bacterium Xanthomonas campestris pv. vesicatoria (Xcv requires type III effector proteins (T3Es for virulence. After translocation into the host cell, T3Es are thought to interact with components of host immunity to suppress defence responses. XopJ is a T3E protein from Xcv that interferes with plant immune responses; however, its host cellular target is unknown. Here we show that XopJ interacts with the proteasomal subunit RPT6 in yeast and in planta to inhibit proteasome activity. A C235A mutation within the catalytic triad of XopJ as well as a G2A exchange within the N-terminal myristoylation motif abolishes the ability of XopJ to inhibit the proteasome. Xcv ΔxopJ mutants are impaired in growth and display accelerated symptom development including tissue necrosis on susceptible pepper leaves. Application of the proteasome inhibitor MG132 restored the ability of the Xcv ΔxopJ to attenuate the development of leaf necrosis. The XopJ dependent delay of tissue degeneration correlates with reduced levels of salicylic acid (SA and changes in defence- and senescence-associated gene expression. Necrosis upon infection with Xcv ΔxopJ was greatly reduced in pepper plants with reduced expression of NPR1, a central regulator of SA responses, demonstrating the involvement of SA-signalling in the development of XopJ dependent phenotypes. Our results suggest that XopJ-mediated inhibition of the proteasome interferes with SA-dependent defence response to attenuate onset of necrosis and to alter host transcription. A central role of the proteasome in plant defence is discussed.

  6. Light acclimation, retrograde signalling, cell death and immune defences in plants.

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    Karpiński, Stanisław; Szechyńska-Hebda, Magdalena; Wituszyńska, Weronika; Burdiak, Paweł

    2013-04-01

    This review confronts the classical view of plant immune defence and light acclimation with recently published data. Earlier findings have linked plant immune defences to nucleotide-binding site leucine-rich repeat (NBS-LRR)-dependent recognition of pathogen effectors and to the role of plasma membrane-localized NADPH-dependent oxidoreductase (AtRbohD), reactive oxygen species (ROS) and salicylic acid (SA). However, recent results suggest that plant immune defence also depends on the absorption of excessive light energy and photorespiration. Rapid changes in light intensity and quality often cause the absorption of energy, which is in excess of that required for photosynthesis. Such excessive light energy is considered to be a factor triggering photoinhibition and disturbance in ROS/hormonal homeostasis, which leads to cell death in foliar tissues. We highlight here the tight crosstalk between ROS- and SA-dependent pathways leading to light acclimation, and defence responses leading to pathogen resistance. We also show that LESION SIMULATING DISEASE 1 (LSD1) regulates and integrates these processes. Moreover, we discuss the role of plastid-nucleus signal transduction, photorespiration, photoelectrochemical signalling and 'light memory' in the regulation of acclimation and immune defence responses. All of these results suggest that plants have evolved a genetic system that simultaneously regulates systemic acquired resistance (SAR), cell death and systemic acquired acclimation (SAA). © 2012 Blackwell Publishing Ltd.

  7. Anionic Host Defence Peptides from the Plant Kingdom: Their Anticancer Activity and Mechanisms of Action.

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    Harris, Frederick; Prabhu, Saurabh; Dennison, Sarah R; Snape, Timothy J; Lea, Robert; Mura, Manuela; Phoenix, David A

    2016-01-01

    It is becoming increasingly clear that plants ranging across the plant kingdom produce anionic host defence peptides (AHDPs) with potent activity against a wide variety of human cancers cells. In general, this activity involves membrane partitioning by AHDPs, which leads to membranolysis and / or internalization to attack intracellular targets such as DNA. Several models have been proposed to describe these events including: the toroidal pore and Shai-Matsuzaki-Huang mechanisms but, in general, the mechanisms underpinning the membrane interactions and anticancer activity of these peptides are poorly understood. Plant AHDPs with anticancer activity can be conveniently discussed with reference to two groups: cyclotides, which possess cyclic molecules stabilized by cysteine knot motifs, and other ADHPs that adopt extended and α-helical conformations. Here, we review research into the anticancer action of these two groups of peptides along with current understanding of the mechanisms underpinning this action.

  8. Anisakis--a food-borne parasite that triggers allergic host defences.

    Science.gov (United States)

    Nieuwenhuizen, Natalie E; Lopata, Andreas L

    2013-11-01

    Anisakis is a parasitic nematode which infects fish and marine invertebrates, including crustaceans and molluscs. Ingestion of contaminated seafood can cause acute gastrointestinal diseases. Infection can be accompanied by severe allergic reactions such as urticaria, angioedema and anaphylaxis. Diagnosis of allergy due to Anisakis currently relies on the detection of serum IgE antibodies to allergenic proteins and a history of reactions upon exposure to fish. Anisakis proteins demonstrate considerable immunological cross-reactivity to proteins of related nematodes and other invertebrates such as crustaceans and house dust-mites. In contrast, very limited molecular associations with other parasite groups are observed, including trematodes and cestodes. This review outlines current knowledge on Anisakis as a food-borne parasite, with special focus on the underlying immunological mechanisms resulting in allergic host defence responses. Copyright © 2013 Australian Society for Parasitology Inc. Published by Elsevier Ltd. All rights reserved.

  9. Immunosuppressive CD71+ erythroid cells compromise neonatal host defence against infection

    Science.gov (United States)

    Elahi, Shokrollah; Ertelt, James M.; Kinder, Jeremy M.; Jiang, Tony T.; Zhang, Xuzhe; Xin, Lijun; Chaturvedi, Vandana; Strong, Beverly S.; Qualls, Joseph E.; Steinbrecher, Kris A.; Kalfa, Theodosia A.; Shaaban, Aimen F.; Way, Sing Sing

    2013-12-01

    Newborn infants are highly susceptible to infection. This defect in host defence has generally been ascribed to the immaturity of neonatal immune cells; however, the degree of hyporesponsiveness is highly variable and depends on the stimulation conditions. These discordant responses illustrate the need for a more unified explanation for why immunity is compromised in neonates. Here we show that physiologically enriched CD71+ erythroid cells in neonatal mice and human cord blood have distinctive immunosuppressive properties. The production of innate immune protective cytokines by adult cells is diminished after transfer to neonatal mice or after co-culture with neonatal splenocytes. Neonatal CD71+ cells express the enzyme arginase-2, and arginase activity is essential for the immunosuppressive properties of these cells because molecular inhibition of this enzyme or supplementation with L-arginine overrides immunosuppression. In addition, the ablation of CD71+ cells in neonatal mice, or the decline in number of these cells as postnatal development progresses parallels the loss of suppression, and restored resistance to the perinatal pathogens Listeria monocytogenes and Escherichia coli. However, CD71+ cell-mediated susceptibility to infection is counterbalanced by CD71+ cell-mediated protection against aberrant immune cell activation in the intestine, where colonization with commensal microorganisms occurs swiftly after parturition. Conversely, circumventing such colonization by using antimicrobials or gnotobiotic germ-free mice overrides these protective benefits. Thus, CD71+ cells quench the excessive inflammation induced by abrupt colonization with commensal microorganisms after parturition. This finding challenges the idea that the susceptibility of neonates to infection reflects immune-cell-intrinsic defects and instead highlights processes that are developmentally more essential and inadvertently mitigate innate immune protection. We anticipate that these

  10. Host defence during Klebsiella pneumonia relies on haematopoietic-expressed Toll-like receptors 4 and 2

    NARCIS (Netherlands)

    Wieland, C. W.; van Lieshout, M. H. P.; Hoogendijk, A. J.; van der Poll, T.

    2011-01-01

    In this study, the relative roles of Toll-like receptor (TLR)2 and TLR4 were investigated independently and together. Moreover, we studied the role of haematopoietic compartment in anti-Klebsiella host defence. We infected TLR2 and TLR4 single-, and TLR2×4 double knockout (KO) animals with different

  11. The interleukin-17 cytokine family: critical players in host defence and inflammatory diseases.

    Science.gov (United States)

    Pappu, Rajita; Ramirez-Carrozzi, Vladimir; Sambandam, Arivazhagan

    2011-09-01

    The interleukin-17 (IL-17) cytokines, IL-17A to IL-17F, are emerging as critical players in host defence responses and inflammatory diseases. Substantial data support the role of these proteins in innate and adaptive immunity. Of these family members, IL-17A, IL-17F and IL-17E have been the best studied. Both IL-17A and IL-17F contribute to the host response to extracellular bacteria and fungi, and IL-17E has been shown to play a role in parasitic infections. In addition, numerous pre-clinical and clinical studies link these proteins to the pathogenesis of inflammatory diseases, and a number of therapeutic programmes targeting these family members are in clinical development. This review will highlight the cellular sources, receptors/target cells, and role in inflammation of these and the less-characterized family members, IL-17B, IL-17C and IL-17D. © 2011 Genentech, Inc. Immunology © 2011 Blackwell Publishing Ltd.

  12. Yersinia virulence factors - a sophisticated arsenal for combating host defences [version 1; referees: 2 approved

    Directory of Open Access Journals (Sweden)

    Steve Atkinson

    2016-06-01

    Full Text Available The human pathogens Yersinia pseudotuberculosis and Yersinia enterocolitica cause enterocolitis, while Yersinia pestis is responsible for pneumonic, bubonic, and septicaemic plague. All three share an infection strategy that relies on a virulence factor arsenal to enable them to enter, adhere to, and colonise the host while evading host defences to avoid untimely clearance. Their arsenal includes a number of adhesins that allow the invading pathogens to establish a foothold in the host and to adhere to specific tissues later during infection. When the host innate immune system has been activated, all three pathogens produce a structure analogous to a hypodermic needle. In conjunction with the translocon, which forms a pore in the host membrane, the channel that is formed enables the transfer of six ‘effector’ proteins into the host cell cytoplasm. These proteins mimic host cell proteins but are more efficient than their native counterparts at modifying the host cell cytoskeleton, triggering the host cell suicide response. Such a sophisticated arsenal ensures that yersiniae maintain the upper hand despite the best efforts of the host to counteract the infecting pathogen.

  13. Cathelicidin host defence peptide augments clearance of pulmonary Pseudomonas aeruginosa infection by its influence on neutrophil function in vivo.

    Directory of Open Access Journals (Sweden)

    Paula E Beaumont

    Full Text Available Cathelicidins are multifunctional cationic host-defence peptides (CHDP; also known as antimicrobial peptides and an important component of innate host defence against infection. In addition to microbicidal potential, these peptides have properties with the capacity to modulate inflammation and immunity. However, the extent to which such properties play a significant role during infection in vivo has remained unclear. A murine model of acute P. aeruginosa lung infection was utilised, demonstrating cathelicidin-mediated enhancement of bacterial clearance in vivo. The delivery of exogenous synthetic human cathelicidin LL-37 was found to enhance a protective pro-inflammatory response to infection, effectively promoting bacterial clearance from the lung in the absence of direct microbicidal activity, with an enhanced early neutrophil response that required both infection and peptide exposure and was independent of native cathelicidin production. Furthermore, although cathelicidin-deficient mice had an intact early cellular inflammatory response, later phase neutrophil response to infection was absent in these animals, with significantly impaired clearance of P. aeruginosa. These findings demonstrate the importance of the modulatory properties of cathelicidins in pulmonary infection in vivo and highlight a key role for cathelicidins in the induction of protective pulmonary neutrophil responses, specific to the infectious milieu. In additional to their physiological roles, CHDP have been proposed as future antimicrobial therapeutics. Elucidating and utilising the modulatory properties of cathelicidins has the potential to inform the development of synthetic peptide analogues and novel therapeutic approaches based on enhancing innate host defence against infection with or without direct microbicidal targeting of pathogens.

  14. Gastrointestinal host defence: importance of gut closure in control of macromolecular transport.

    Science.gov (United States)

    Walker, W A

    An important adaptation of the gastrointestinal tract to the extrauterine environment is its development of a mucosal barrier against the penetration of harmful substances (bacteria, toxins and antigens) present within the intestinal lumen. At birth, the newborn infant must be prepared to deal with bacterial colonization of the gut, with formation of toxic byproducts of bacteria and viruses (enterotoxins and endotoxins) and with the ingestion of antigens (milk proteins). These potentially noxious substances if allowed to penetrate the mucosal epithelial barrier under pathological conditions can cause inflammatory and allergic reactions which may result in gastrointestinal and systemic disease states. To combat the potential danger of invasion across the mucosal barrier the infant must develop an elaborate system of defence mechanisms within the lumen and on the luminal mucosal surface which act to control and maintain the epithelium as an impermeable barrier to uptake of macromolecular antigens. These defences include a unique immunological system adapted to function in the complicated milieu of the intestine as well as other non-immunological processes such as a gastric barrier, intestinal surface secretions, peristaltic movement and natural antibacterial substances (lysozyme, bile salts) which also help to provide maximum protection for the intestinal surface. Unfortunately, during the immediate postpartum period, particularly for premature and small-for-dates infants, this elaborate local defence system is incompletely developed. As a result of the delay in the maturation of the mucosal barrier newborn infants are particularly vulnerable to pathological penetration by harmful intraluminal substances. The consequences of altered defence are susceptibility to infection and the potential for hypersensitivity reactions and for formation of immune complexes. With these reactions comes the potential for developing life-threatening diseases such as necrotizing

  15. Genome wide expression profiling reveals suppression of host defence responses during colonisation by Neisseria meningitides but not N. lactamica.

    Directory of Open Access Journals (Sweden)

    Hazel En En Wong

    Full Text Available Both Neisseria meningitidis and the closely related bacterium Neisseria lactamica colonise human nasopharyngeal mucosal surface, but only N. meningitidis invades the bloodstream to cause potentially life-threatening meningitis and septicaemia. We have hypothesised that the two neisserial species differentially modulate host respiratory epithelial cell gene expression reflecting their disease potential. Confluent monolayers of 16HBE14 human bronchial epithelial cells were exposed to live and/or dead N. meningitidis (including capsule and pili mutants and N. lactamica, and their transcriptomes were compared using whole genome microarrays. Changes in expression of selected genes were subsequently validated using Q-RT-PCR and ELISAs. Live N. meningitidis and N. lactamica induced genes involved in host energy production processes suggesting that both bacterial species utilise host resources. N. meningitidis infection was associated with down-regulation of host defence genes. N. lactamica, relative to N. meningitidis, initiates up-regulation of proinflammatory genes. Bacterial secreted proteins alone induced some of the changes observed. The results suggest N. meningitidis and N. lactamica differentially regulate host respiratory epithelial cell gene expression through colonisation and/or protein secretion, and that this may contribute to subsequent clinical outcomes associated with these bacteria.

  16. Mycobacterium tuberculosis effectors interfering host apoptosis signaling.

    Science.gov (United States)

    Liu, Minqiang; Li, Wu; Xiang, Xiaohong; Xie, Jianping

    2015-07-01

    Tuberculosis remains a serious human public health concern. The coevolution between its pathogen Mycobacterium tuberculosis and human host complicated the way to prevent and cure TB. Apoptosis plays subtle role in this interaction. The pathogen endeavors to manipulate the apoptosis via diverse effectors targeting key signaling nodes. In this paper, we summarized the effectors pathogen used to subvert the apoptosis, such as LpqH, ESAT-6/CFP-10, LAMs. The interplay between different forms of cell deaths, such as apoptosis, autophagy, necrosis, is also discussed with a focus on the modes of action of effectors, and implications for better TB control.

  17. OsMYC2 mediates numerous defence-related transcriptional changes via jasmonic acid signalling in rice.

    Science.gov (United States)

    Ogawa, Satoshi; Kawahara-Miki, Ryouka; Miyamoto, Koji; Yamane, Hisakazu; Nojiri, Hideaki; Tsujii, Yoshimasa; Okada, Kazunori

    2017-05-06

    Jasmonic acid (JA) plays central roles in various events in plants, especially defence against pathogens and insects. The basic helix-loop-helix (bHLH) transcription factor MYC2 has attracted attention as a master regulator of JA signalling in dicotyledonous plants. However, how MYC2 functions in monocotyledonous plants, including agriculturally important crops such as cultivated rice, has been poorly understood. To elucidate the comprehensive effects of rice MYC2 (OsMYC2) on the JA-inducible transcriptional modifications, we performed RNA-sequencing by using OsMYC2-knockdown plants (osmyc2RNAi). In osmyc2RNAi, JA-inducible expression of many defence-related genes, for example chitinases and proteinase inhibitors, was compromised. Decrease in JA-dependent activation of the biosynthetic pathways of specialised metabolites, especially defence compounds, was also evident in the osmyc2RNAi line. Furthermore, a substantial change was noted in the expression of distinct types of transcription factors, such as MYB-type factors, likely depicting the importance of OsMYC2 in not only defence responses but also other morphogenetic events. Our findings provide fundamental information to understand the overall functions of MYC2 in JA signalling in monocotyledonous plants, which might yield agricultural benefits. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. Chemical signaling in mosquito–host interactions

    NARCIS (Netherlands)

    Takken, Willem; Verhulst, Niels O.

    2017-01-01

    Anthropophilic mosquitoes use host-derived volatile compounds for host seeking. Recently it has become evident that many of these compounds are of microbial origin. Host seeking of mosquitoes is, therefore, a tritrophic relationship and suggests co-evolution between blood hosts and their

  19. Differential expression of immune defences is associated with specific host-parasite interactions in insects.

    Directory of Open Access Journals (Sweden)

    Carolyn Riddell

    2009-10-01

    Full Text Available Recent ecological studies in invertebrates show that the outcome of an infection is dependent on the specific pairing of host and parasite. Such specificity contrasts the long-held view that invertebrate innate immunity depends on a broad-spectrum recognition system. An important question is whether this specificity is due to the immune response rather than some other interplay between host and parasite genotypes. By measuring the expression of putative bumblebee homologues of antimicrobial peptides in response to infection by their gut trypanosome Crithidia bombi, we demonstrate that expression differences are associated with the specific interactions.

  20. Defence signalling triggered by Flg22 and Harpin is integrated into a different stilbene output in Vitis cells.

    Science.gov (United States)

    Chang, Xiaoli; Nick, Peter

    2012-01-01

    Plants can activate defence to pathogen attack by two layers of innate immunity: basal immunity triggered by pathogen-associated molecular pattern (PAMP) triggered immunity (PTI) and effector-triggered immunity (ETI) linked with programmed cell death. Flg22 and Harpin are evolutionary distinct bacterial PAMPs. We have previously shown that Harpin triggers hypersensitive cell death mimicking ETI in Vitis rupestris, but not in the Vitis vinifera cultivar 'Pinot Noir'. In contrast, the bacterial PAMP flg22 activating PTI does not trigger cell death. To get insight into the defence signalling triggered by flg22 and Harpin, we compared cellular responses upon flg22 and Harpin treatment in the two Vitis cell lines. We found that extracellular alkalinisation was blocked by inhibition of calcium influx, and modulated by pharmacological manipulation of the cytoskeleton and mitogen-activated protein kinase activity with quantitative differences between cell lines and type of PAMPs. In addition, an oxidative burst was detected that was much stronger and faster in response to Harpin as compared to flg22. In V. rupestris, both flg22 and Harpin induced transcripts of defence-related genes including stilbene synthase, microtubule disintegration and actin bundling in a similar way, whereas they differed in V. vinifera cv. 'Pinot Noir'. In contrast to Harpin, flg22 failed to trigger significant levels of the stilbene trans-resveratrol, and did not induce hypersensitive cell death even in the highly responsive V. rupestris. We discuss these data in a model, where flg22- and Harpin-triggered defence shares a part of early signal components, but differs in perception, oxidative burst, and integration into a qualitatively different stilbene output, such that for flg22 a basal PTI is elicited in both cell lines, while Harpin induces cell death mimicking an ETI-like pattern of defence.

  1. Defence signalling triggered by Flg22 and Harpin is integrated into a different stilbene output in Vitis cells.

    Directory of Open Access Journals (Sweden)

    Xiaoli Chang

    Full Text Available Plants can activate defence to pathogen attack by two layers of innate immunity: basal immunity triggered by pathogen-associated molecular pattern (PAMP triggered immunity (PTI and effector-triggered immunity (ETI linked with programmed cell death. Flg22 and Harpin are evolutionary distinct bacterial PAMPs. We have previously shown that Harpin triggers hypersensitive cell death mimicking ETI in Vitis rupestris, but not in the Vitis vinifera cultivar 'Pinot Noir'. In contrast, the bacterial PAMP flg22 activating PTI does not trigger cell death. To get insight into the defence signalling triggered by flg22 and Harpin, we compared cellular responses upon flg22 and Harpin treatment in the two Vitis cell lines. We found that extracellular alkalinisation was blocked by inhibition of calcium influx, and modulated by pharmacological manipulation of the cytoskeleton and mitogen-activated protein kinase activity with quantitative differences between cell lines and type of PAMPs. In addition, an oxidative burst was detected that was much stronger and faster in response to Harpin as compared to flg22. In V. rupestris, both flg22 and Harpin induced transcripts of defence-related genes including stilbene synthase, microtubule disintegration and actin bundling in a similar way, whereas they differed in V. vinifera cv. 'Pinot Noir'. In contrast to Harpin, flg22 failed to trigger significant levels of the stilbene trans-resveratrol, and did not induce hypersensitive cell death even in the highly responsive V. rupestris. We discuss these data in a model, where flg22- and Harpin-triggered defence shares a part of early signal components, but differs in perception, oxidative burst, and integration into a qualitatively different stilbene output, such that for flg22 a basal PTI is elicited in both cell lines, while Harpin induces cell death mimicking an ETI-like pattern of defence.

  2. γδ T cells in homeostasis and host defence of epithelial barrier tissues

    DEFF Research Database (Denmark)

    Nielsen, Morten M.; Witherden, Deborah A.; Havran, Wendy L.

    2017-01-01

    homeostasis and repair. In this Review, we focus on the intraepithelial γδ T cell compartment of the two largest epithelial tissues in the body — namely, the epidermis and the intestine — and provide a comprehensive overview of the crucial contributions of intraepithelial γδ T cells to tissue integrity...... and repair, host homeostasis and protection in the context of the symbiotic relationship with the microbiome and during pathogen clearance. Finally, we describe epithelium-specific butyrophilin-like molecules and briefly review their emerging role in selectively shaping and regulating epidermal...

  3. Phospholipase D and phosphatidic acid in plant defence response: from protein–protein and lipid–protein interactions to hormone signalling

    Science.gov (United States)

    Zhao, Jian

    2015-01-01

    Phospholipase Ds (PLDs) and PLD-derived phosphatidic acids (PAs) play vital roles in plant hormonal and environmental responses and various cellular dynamics. Recent studies have further expanded the functions of PLDs and PAs into plant–microbe interaction. The molecular diversities and redundant functions make PLD–PA an important signalling complex regulating lipid metabolism, cytoskeleton dynamics, vesicle trafficking, and hormonal signalling in plant defence through protein–protein and protein–lipid interactions or hormone signalling. Different PLD–PA signalling complexes and their targets have emerged as fast-growing research topics for understanding their numerous but not yet established roles in modifying pathogen perception, signal transduction, and downstream defence responses. Meanwhile, advanced lipidomics tools have allowed researchers to reveal further the mechanisms of PLD–PA signalling complexes in regulating lipid metabolism and signalling, and their impacts on jasmonic acid/oxylipins, salicylic acid, and other hormone signalling pathways that essentially mediate plant defence responses. This review attempts to summarize the progress made in spatial and temporal PLD/PA signalling as well as PLD/PA-mediated modification of plant defence. It presents an in-depth discussion on the functions and potential mechanisms of PLD–PA complexes in regulating actin filament/microtubule cytoskeleton, vesicle trafficking, and hormonal signalling, and in influencing lipid metabolism-derived metabolites as critical signalling components in plant defence responses. The discussion puts PLD–PA in a broader context in order to guide future research. PMID:25680793

  4. γδ T cells in homeostasis and host defence of epithelial barrier tissues.

    Science.gov (United States)

    Nielsen, Morten M; Witherden, Deborah A; Havran, Wendy L

    2017-12-01

    Epithelial surfaces line the body and provide a crucial interface between the body and the external environment. Tissue-resident epithelial γδ T cells represent a major T cell population in the epithelial tissues and are ideally positioned to carry out barrier surveillance and aid in tissue homeostasis and repair. In this Review, we focus on the intraepithelial γδ T cell compartment of the two largest epithelial tissues in the body - namely, the epidermis and the intestine - and provide a comprehensive overview of the crucial contributions of intraepithelial γδ T cells to tissue integrity and repair, host homeostasis and protection in the context of the symbiotic relationship with the microbiome and during pathogen clearance. Finally, we describe epithelium-specific butyrophilin-like molecules and briefly review their emerging role in selectively shaping and regulating epidermal and intestinal γδ T cell repertoires.

  5. BAY 41-2272 activates host defence against local and disseminated Candida albicans infections

    Directory of Open Access Journals (Sweden)

    Paulo Vítor Soeiro-Pereira

    2015-02-01

    Full Text Available In our previous study, we have found that 5-cyclopropyl-2-[1-(2-fluoro-benzyl-1H-pyrazolo[3,4-b]pyridine-3-yl]-pyrimidin-4-ylamine (BAY 41-2272, a guanylate cyclase agonist, activates human monocytes and the THP-1 cell line to produce the superoxide anion, increasing in vitro microbicidal activity, suggesting that this drug can be used to modulate immune functioning in primary immunodeficiency patients. In the present work, we investigated the potential of the in vivo administration of BAY 41-2272 for the treatment of Candida albicans and Staphylococcus aureus infections introduced via intraperitoneal and subcutaneous inoculation. We found that intraperitoneal treatment with BAY 41-2272 markedly increased macrophage-dependent cell influx to the peritoneum in addition to macrophage functions, such as spreading, zymosan particle phagocytosis and nitric oxide and phorbol myristate acetate-stimulated hydrogen peroxide production. Treatment with BAY 41-2272 was highly effective in reducing the death rate due to intraperitoneal inoculation of C. albicans, but not S. aureus. However, we found that in vitro stimulation of peritoneal macrophages with BAY 41-2272 markedly increased microbicidal activities against both pathogens. Our results show that the prevention of death by the treatment of C. albicans-infected mice with BAY 41-2272 might occur primarily by the modulation of the host immune response through macrophage activation.

  6. Bacterial Immune Evasion through Manipulation of Host Inhibitory Immune Signaling

    NARCIS (Netherlands)

    Van Avondt, Kristof; van Sorge, Nina M.|info:eu-repo/dai/nl/279926812; Meyaard, Linde|info:eu-repo/dai/nl/13444972X

    An innate immune response is essential for survival of the host upon infection, yet excessive inflammation can result in harmful complications [1]. Inhibitory signaling evolved to limit host responses and prevent inflammatory pathology [2,3]. Given the significance of inhibitory pathways for

  7. Phospholipase D and phosphatidic acid in plant defence response: from protein-protein and lipid-protein interactions to hormone signalling.

    Science.gov (United States)

    Zhao, Jian

    2015-04-01

    Phospholipase Ds (PLDs) and PLD-derived phosphatidic acids (PAs) play vital roles in plant hormonal and environmental responses and various cellular dynamics. Recent studies have further expanded the functions of PLDs and PAs into plant-microbe interaction. The molecular diversities and redundant functions make PLD-PA an important signalling complex regulating lipid metabolism, cytoskeleton dynamics, vesicle trafficking, and hormonal signalling in plant defence through protein-protein and protein-lipid interactions or hormone signalling. Different PLD-PA signalling complexes and their targets have emerged as fast-growing research topics for understanding their numerous but not yet established roles in modifying pathogen perception, signal transduction, and downstream defence responses. Meanwhile, advanced lipidomics tools have allowed researchers to reveal further the mechanisms of PLD-PA signalling complexes in regulating lipid metabolism and signalling, and their impacts on jasmonic acid/oxylipins, salicylic acid, and other hormone signalling pathways that essentially mediate plant defence responses. This review attempts to summarize the progress made in spatial and temporal PLD/PA signalling as well as PLD/PA-mediated modification of plant defence. It presents an in-depth discussion on the functions and potential mechanisms of PLD-PA complexes in regulating actin filament/microtubule cytoskeleton, vesicle trafficking, and hormonal signalling, and in influencing lipid metabolism-derived metabolites as critical signalling components in plant defence responses. The discussion puts PLD-PA in a broader context in order to guide future research. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  8. Signalling requirements for Erwinia amylovora-induced disease resistance, callose deposition and cell growth in the non-host Arabidopsis thaliana.

    Science.gov (United States)

    Hamdoun, Safae; Gao, Min; Gill, Manroop; Kwon, Ashley; Norelli, John L; Lu, Hua

    2017-07-29

    Erwinia amylovora is the causal agent of the fire blight disease in some plants of the Rosaceae family. The non-host plant Arabidopsis serves as a powerful system for the dissection of mechanisms of resistance to E. amylovora. Although not yet known to mount gene-for-gene resistance to E. amylovora, we found that Arabidopsis activated strong defence signalling mediated by salicylic acid (SA), with kinetics and amplitude similar to that induced by the recognition of the bacterial effector avrRpm1 by the resistance protein RPM1. Genetic analysis further revealed that SA signalling, but not signalling mediated by ethylene (ET) and jasmonic acid (JA), is required for E. amylovora resistance. Erwinia amylovora induces massive callose deposition on infected leaves, which is independent of SA, ET and JA signalling and is necessary for E. amylovora resistance in Arabidopsis. We also observed tumour-like growths on E. amylovora-infected Arabidopsis leaves, which contain enlarged mesophyll cells with increased DNA content and are probably a result of endoreplication. The formation of such growths is largely independent of SA signalling and some E. amylovora effectors. Together, our data reveal signalling requirements for E. amylovora-induced disease resistance, callose deposition and cell fate change in the non-host plant Arabidopsis. Knowledge from this study could facilitate a better understanding of the mechanisms of host defence against E. amylovora and eventually improve host resistance to the pathogen. © 2017 BSPP AND JOHN WILEY & SONS LTD.

  9. The interaction of the novel 30C02 cyst nematode effector protein with a plant β-1,3-endoglucanase may suppress host defence to promote parasitism

    Science.gov (United States)

    Hamamouch, Noureddine; Hewezi, Tarek; Baum, Thomas J.; Mitchum, Melissa G.; Hussey, Richard S.; Vodkin, Lila O.; Davis, Eric L.

    2012-01-01

    Phytoparasitic nematodes secrete an array of effector proteins to modify selected recipient plant cells into elaborate and essential feeding sites. The biological function of the novel 30C02 effector protein of the soybean cyst nematode, Heterodera glycines, was studied using Arabidopsis thaliana as host and the beet cyst nematode, Heterodera schachtii, which contains a homologue of the 30C02 gene. Expression of Hg30C02 in Arabidopsis did not affect plant growth and development but increased plant susceptibility to infection by H. schachtii. The 30C02 protein interacted with a specific (AT4G16260) host plant β-1,3-endoglucanase in both yeast and plant cells, possibly to interfere with its role as a plant pathogenesis-related protein. Interestingly, the peak expression of 30C02 in the nematode and peak expression of At4g16260 in plant roots coincided at around 3–5 d after root infection by the nematode, after which the relative expression of At4g16260 declined significantly. An Arabidopsis At4g16260 T-DNA mutant showed increased susceptibility to cyst nematode infection, and plants that overexpressed At4g16260 were reduced in nematode susceptibility, suggesting a potential role of host β-1,3-endoglucanase in the defence response against H. schachtii infection. Arabidopsis plants that expressed dsRNA and its processed small interfering RNA complementary to the Hg30C02 sequence were not phenotypically different from non-transformed plants, but they exhibited a strong RNA interference-mediated resistance to infection by H. schachtii. The collective results suggest that, as with other pathogens, active suppression of host defence is a critical component for successful parasitism by nematodes and a vulnerable target to disrupt the parasitic cycle. PMID:22442414

  10. Shifting from priming of salicylic acid- to jasmonic acid-regulated defences by Trichoderma protects tomato against the root knot nematode Meloidogyne incognita

    NARCIS (Netherlands)

    Martínez-Medina, Ainhoa; Fernandez, Ivan; Lok, Gerrit B; Pozo, María J; Pieterse, Corné M J; Van Wees, Saskia C M

    Beneficial root endophytes such as Trichoderma spp. can reduce infections by parasitic nematodes through triggering host defences. Little is currently known about the complex hormone signalling underlying the induction of resistance. In this study, we investigated whether Trichoderma modulates the

  11. Active defence responses associated with non-host resistance of Arabidopsis thaliana to the oomycete pathogen Phytophthora infestans

    NARCIS (Netherlands)

    Huitema, E.; Vleeshouwers, V.G.A.A.; Francis, D.M.; Kamoun, S.

    2003-01-01

    The molecular basis of non-host resistance, or species-specific resistance, remains one of the major unknowns in the study of plant¿microbe interactions. In this paper, we describe the characterization of a non-host pathosystem involving the model plant Arabidopsis thaliana and the economically

  12. The structure of lactoferrin-binding protein B from Neisseria meningitidis suggests roles in iron acquisition and neutralization of host defences

    Science.gov (United States)

    Brooks, Cory L.; Arutyunova, Elena; Lemieux, M. Joanne

    2014-01-01

    Pathogens have evolved a range of mechanisms to acquire iron from the host during infection. Several Gram-negative pathogens including members of the genera Neisseria and Moraxella have evolved two-component systems that can extract iron from the host glycoproteins lactoferrin and transferrin. The homologous iron-transport systems consist of a membrane-bound transporter and an accessory lipoprotein. While the mechanism behind iron acquisition from transferrin is well understood, relatively little is known regarding how iron is extracted from lactoferrin. Here, the crystal structure of the N-terminal domain (N-lobe) of the accessory lipoprotein lactoferrin-binding protein B (LbpB) from the pathogen Neisseria meningitidis is reported. The structure is highly homologous to the previously determined structures of the accessory lipoprotein transferrin-binding protein B (TbpB) and LbpB from the bovine pathogen Moraxella bovis. Docking the LbpB structure with lactoferrin reveals extensive binding interactions with the N1 subdomain of lactoferrin. The nature of the interaction precludes apolactoferrin from binding LbpB, ensuring the specificity of iron-loaded lactoferrin. The specificity of LbpB safeguards proper delivery of iron-bound lactoferrin to the transporter lactoferrin-binding protein A (LbpA). The structure also reveals a possible secondary role for LbpB in protecting the bacteria from host defences. Following proteolytic digestion of lactoferrin, a cationic peptide derived from the N-terminus is released. This peptide, called lactoferricin, exhibits potent antimicrobial effects. The docked model of LbpB with lactoferrin reveals that LbpB interacts extensively with the N-terminal lactoferricin region. This may provide a venue for preventing the production of the peptide by proteolysis, or directly sequestering the peptide, protecting the bacteria from the toxic effects of lactoferricin. PMID:25286931

  13. Cladosporium fulvum CfHNNI1 induces hypersensitive necrosis, defence gene expression and disease resistance in both host and nonhost plants.

    Science.gov (United States)

    Cai, Xin-Zhong; Zhou, Xin; Xu, You-Ping; Joosten, Matthieu H A J; de Wit, Pierre J G M

    2007-05-01

    Nonhost resistance as a durable and broad-spectrum defence strategy is of great potential for agricultural applications. We have previously isolated a cDNA showing homology with genes encoding bZIP transcription factors from tomato leaf mould pathogen Cladosporium fulvum. Upon expression, the cDNA results in necrosis in C. fulvum host tomato and nonhost tobacco plants and is thus named CfHNNI1 (for C . f ulvum host and nonhost plant necrosis inducer 1). In the present study we report the induction of necrosis in a variety of nonhost plant species belonging to three families by the transient in planta expression of CfHNNI1 using virus-based vectors. Additionally, transient expression of CfHNNI1 also induced expression of the HR marker gene LeHSR203 and greatly reduced the accumulation of recombinant Potato virus X. Stable CfHNNI1 transgenic tobacco plants were generated in which the expression of CfHNNI1 is under the control of the pathogen-inducible hsr203J promoter. When infected with the oomycetes pathogen Phytophthora parasitica var. nicotianae, these transgenic plants manifested enhanced expression of CfHNNI1 and subsequent accumulation of CfHNNI1 protein, resulting in high expression of the HSR203J and PR genes, and strong resistance to the pathogen. The CfHNNI1 transgenic plants also exhibited induced resistance to Pseudomonas syringae pv. tabaci and Tobacco mosaic virus. Furthermore, CfHNNI1 was highly expressed and the protein was translocated into plant cells during the incompatible interactions between C. fulvum and host and nonhost plants. Our results demonstrate that CfHNNI1 is a potential general elicitor of hypersensitive response and nonhost resistance.

  14. Staphylococcal Superantigens Spark Host-Mediated Danger Signals

    Directory of Open Access Journals (Sweden)

    Terry eKrakauer

    2016-02-01

    Full Text Available Staphylococcal enterotoxin B (SEB of Staphylococcus aureus, and related superantigenic toxins produced by myriad microbes, are potent stimulators of the immune system causing a variety of human diseases from transient food poisoning to lethal toxic shock. These protein toxins bind directly to specific V regions of T-cell receptors (TCR and major histocompatibility complex (MHC class II on antigen-presenting cells, resulting in hyperactivation of T lymphocytes and monocytes / macrophages. Activated host cells produce excessive amounts of proinflammatory cytokines and chemokines, especially tumor necrosis factor α, interleukin 1 (IL-1, IL-2, interferon γ (IFNγ, and macrophage chemoattractant protein 1 causing clinical symptoms of fever, hypotension, and shock. Because of superantigen-induced T cells skewed towards TH1 helper cells, and the induction of proinflammatory cytokines, superantigens can exacerbate autoimmune diseases. Upon TCR / MHC ligation, pathways induced by superantigens include the mitogen-activated protein kinase cascades and cytokine receptor signaling, resulting in activation of NFκB and the phosphoinositide 3-kinase / mammalian target of rapamycin pathways. Various mouse models exist to study SEB-induced shock including those with potentiating agents, transgenic mice and an SEB-only model. However, therapeutics to treat toxic shock remain elusive as host response genes central to pathogenesis of superantigens have only been identified recently. Gene profiling of a murine model for SEB-induced shock reveals novel molecules upregulated in multiple organs not previously associated with SEB-induced responses. The pivotal genes include intracellular DNA / RNA sensors, apoptosis / DNA damage-related molecules, immunoproteasome components, as well as anti-viral and IFN-stimulated genes. The host-wide induction of these, and other, anti-microbial defense genes provide evidence that SEB elicits danger signals resulting in multi

  15. Staphylococcal Superantigens Spark Host-Mediated Danger Signals.

    Science.gov (United States)

    Krakauer, Teresa; Pradhan, Kisha; Stiles, Bradley G

    2016-01-01

    Staphylococcal enterotoxin B (SEB) of Staphylococcus aureus, and related superantigenic toxins produced by myriad microbes, are potent stimulators of the immune system causing a variety of human diseases from transient food poisoning to lethal toxic shock. These protein toxins bind directly to specific Vβ regions of T-cell receptors (TCR) and major histocompatibility complex (MHC) class II on antigen-presenting cells, resulting in hyperactivation of T lymphocytes and monocytes/macrophages. Activated host cells produce excessive amounts of proinflammatory cytokines and chemokines, especially tumor necrosis factor α, interleukin 1 (IL-1), IL-2, interferon γ (IFNγ), and macrophage chemoattractant protein 1 causing clinical symptoms of fever, hypotension, and shock. Because of superantigen-induced T cells skewed toward TH1 helper cells, and the induction of proinflammatory cytokines, superantigens can exacerbate autoimmune diseases. Upon TCR/MHC ligation, pathways induced by superantigens include the mitogen-activated protein kinase cascades and cytokine receptor signaling, resulting in activation of NFκB and the phosphoinositide 3-kinase/mammalian target of rapamycin pathways. Various mouse models exist to study SEB-induced shock including those with potentiating agents, transgenic mice and an "SEB-only" model. However, therapeutics to treat toxic shock remain elusive as host response genes central to pathogenesis of superantigens have only been identified recently. Gene profiling of a murine model for SEB-induced shock reveals novel molecules upregulated in multiple organs not previously associated with SEB-induced responses. The pivotal genes include intracellular DNA/RNA sensors, apoptosis/DNA damage-related molecules, immunoproteasome components, as well as antiviral and IFN-stimulated genes. The host-wide induction of these, and other, antimicrobial defense genes provide evidence that SEB elicits danger signals resulting in multi-organ damage and toxic shock

  16. Moving nitrogen to the centre of plant defence against pathogens.

    Science.gov (United States)

    Mur, Luis A J; Simpson, Catherine; Kumari, Aprajita; Gupta, Alok Kumar; Gupta, Kapuganti Jagadis

    2017-03-01

    Plants require nitrogen (N) for growth, development and defence against abiotic and biotic stresses. The extensive use of artificial N fertilizers has played an important role in the Green Revolution. N assimilation can involve a reductase series ( NO3- → NO2- → NH4+ ) followed by transamination to form amino acids. Given its widespread use, the agricultural impact of N nutrition on disease development has been extensively examined. When a pathogen first comes into contact with a host, it is usually nutrient starved such that rapid assimilation of host nutrients is essential for successful pathogenesis. Equally, the host may reallocate its nutrients to defence responses or away from the site of attempted infection. Exogenous application of N fertilizer can, therefore, shift the balance in favour of the host or pathogen. In line with this, increasing N has been reported either to increase or to decrease plant resistance to pathogens, which reflects differences in the infection strategies of discrete pathogens. Beyond considering only N content, the use of NO3- or NH4+ fertilizers affects the outcome of plant-pathogen interactions. NO3- feeding augments hypersensitive response- (HR) mediated resistance, while ammonium nutrition can compromise defence. Metabolically, NO3- enhances production of polyamines such as spermine and spermidine, which are established defence signals, with NH4+ nutrition leading to increased γ-aminobutyric acid (GABA) levels which may be a nutrient source for the pathogen. Within the defensive N economy, the roles of nitric oxide must also be considered. This is mostly generated from NO2- by nitrate reductase and is elicited by both pathogen-associated microbial patterns and gene-for-gene-mediated defences. Nitric oxide (NO) production and associated defences are therefore NO3- dependent and are compromised by NH4+ . This review demonstrates how N content and form plays an essential role in defensive primary and secondary metabolism and

  17. Wolbachia as an infectious extrinsic factor manipulating host signalling pathways

    Directory of Open Access Journals (Sweden)

    Ilaria eNegri

    2012-01-01

    Full Text Available Wolbachia pipientis is a widespread endosymbiont of filarial nematodes and arthropods. While in worms the symbiosis is obligate, in arthropods Wolbachia induces several reproductive manipulations (i.e. cytoplasmic incompatibility, parthenogenesis, feminization of genetic males and male-killing in order to increase the number of infected females. These various phenotypic effects may be linked to differences in host physiology, and in particular to endocrine-related processes governing growth, development and reproduction. Indeed, a number of evidences links Wolbachia symbiosis to insulin and ecdysteroid signalling, two multilayered pathways known to work antagonistically, jointly or even independently for the regulation of different molecular networks. At present it is not clear whether Wolbachia manipulates one pathway, thus affecting other related metabolic networks, or if it targets both pathways, even interacting at several points in each of them. Interestingly, in view of the interplay between hormone signalling and epigenetic machinery, a direct influence of the infection on hormonal signalling involving ecdysteroids might be achievable through the manipulation of the host’s epigenetic pathways.

  18. Airborne signals from Trichoderma fungi stimulate iron uptake responses in roots resulting in priming of jasmonic acid-dependent defences in shoots of Arabidopsis thaliana and Solanum lycopersicum.

    Science.gov (United States)

    Martínez-Medina, Ainhoa; Van Wees, Saskia C M; Pieterse, Corné M J

    2017-11-01

    Root colonization by Trichoderma fungi can trigger induced systemic resistance (ISR). In Arabidopsis, Trichoderma-ISR relies on the transcription factor MYB72, which plays a dual role in the onset of ISR and the activation of Fe uptake responses. Volatile compounds (VCs) from rhizobacteria are important elicitors of MYB72 in Arabidopsis roots. Here, we investigated the mode of action of VCs from Trichoderma fungi in the onset of ISR and Fe uptake responses. VCs from Trichoderma asperellum and Trichoderma harzianum were applied in an in vitro split-plate system with Arabidopsis or tomato seedlings. Locally, Trichoderma-VCs triggered MYB72 expression and molecular, physiological and morphological Fe uptake mechanisms in Arabidopsis roots. In leaves, Trichoderma-VCs primed jasmonic acid-dependent defences, leading to an enhanced resistance against Botrytis cinerea. By using Arabidopsis micrografts of VCs-exposed rootstocks and non-exposed scions, we demonstrated that perception of Trichoderma-VCs by the roots leads to a systemic signal that primes shoots for enhanced defences. Trichoderma-VCs also elicited Fe deficiency responses and shoot immunity in tomato, suggesting that this phenomenon is expressed in different plant species. Our results indicate that Trichoderma-VCs trigger locally a readjustment of Fe homeostasis in roots, which links to systemic elicitation of ISR by priming of jasmonic acid-dependent defences. © 2017 John Wiley & Sons Ltd.

  19. LuxS signaling in Porphyromonas gingivalis-host interactions.

    Science.gov (United States)

    Scheres, Nina; Lamont, Richard J; Crielaard, Wim; Krom, Bastiaan P

    2015-10-01

    Dental plaque is a multispecies biofilm in the oral cavity that significantly influences oral health. The presence of the oral anaerobic pathogen Porphyromonas gingivalis is an important determinant in the development of periodontitis. Direct and indirect interactions between P. gingivalis and the host play a major role in disease development. Transcriptome analysis recently revealed that P. gingivalis gene-expression is regulated by LuxS in both an AI-2-dependent and an AI-2 independent manner. However, little is known about the role of LuxS-signaling in P. gingivalis-host interactions. Here, we investigated the effect of a luxS mutation on the ability of P. gingivalis to induce an inflammatory response in human oral cells in vitro. Primary periodontal ligament (PDL) fibroblasts were challenged with P. gingivalis ΔluxS or the wild-type parental strain and gene-expression of pro-inflammatory mediators IL-1β, IL-6 and MCP-1 was determined by real-time PCR. The ability of P. gingivalis ΔluxS to induce an inflammatory response was severely impaired in PDL-fibroblasts. This phenotype could be restored by providing of LuxS in trans, but not by addition of the AI-2 precursor DPD. A similar phenomenon was observed in a previous transcriptome study showing that expression of PGN_0482 was reduced in the luxS mutant independently of AI-2. We therefore also analyzed the effect of a mutation in PGN_0482, which encodes an immuno-reactive, putative outer-membrane protein. Similar to P. gingivalis ΔluxS, the P. gingivalis Δ0482 mutant had an impaired ability to induce an inflammatory response in PDL fibroblasts. LuxS thus appears to influence the pro-inflammatory responses of host cells to P. gingivalis, likely through regulation of PGN_0482. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. The host-defence skin peptide profiles of Peron's Tree Frog Litoria peronii in winter and summer. Sequence determination by electrospray mass spectrometry and activities of the peptides.

    Science.gov (United States)

    Bilusich, Daniel; Jackway, Rebecca J; Musgrave, Ian F; Tyler, Michael J; Bowie, John H

    2009-09-01

    Positive and negative ion electrospray mass spectrometry together with Edman sequencing (when appropriate) has been used to sequence the host-defence peptides secreted from skin glands of the tree frog Litoria peronii. The peptide profiles are different in winter and summer. In winter, the frog produces small amounts of the known caerin 1.1 [GLLSVLGSVAKHVLPHVVPVIAEHL-NH(2)] (a wide-spectrum antibiotic) and caerin 2.1 [GLVSSIGRALGGLLADVVKSKQPA-OH], a narrow-spectrum antibiotic and an inhibitor of neuronal nitric oxide synthase. The major peptides produced throughout the year are the pGlu-containing peroniins 1.1 to 1.5 (e.g. peroniin 1.1 [pEPWLPFG-NH(2)], a smooth muscle contractor from 10(-7) M), and caerulein [pEQDY(SO(3)H)TGWMDF-NH(2)], a known and potent smooth muscle contractor from 10(-10) M. There are also some precursors to the peroniin 1 peptides, only detected in the skin secretion in summer, which are inactive and appear to be all (or part) of the spacer peroniin 1 peptides, e.g. peroniin 1.1b [SEEEKRQPWLPFG-NH(2)]. There are three members of the Litoria peronii Group of tree frogs classified in Australia, namely, L. peronii, L. rothii and L.tyleri. A comparison of the skin peptide profiles of L. peronii with those reported previously for L. rothii suggests that either these two species of tree frog are not as closely related as determined previously on morphological grounds, or that skin peptide divergence in tree frogs of this Group is more extensive than in others that have been studied. Copyright (c) 2009 John Wiley & Sons, Ltd.

  1. Complement genetics and host defence.

    Science.gov (United States)

    Lachmann, P J

    1990-12-01

    There is a surprisingly high frequency of allelic variation in complement proteins. The best candidate for a true selective polymorphism is that of C3. For C4 and factor B within the MHC it is more difficult to identify the effects of individual alleles. No evidence suggests other alleles of C4 (and C2) than the null alleles (or the two isoproteins C4A and C4B) to have any functional differences with resistance. Thus, the major functions of complement, as shown by the effects of deficiency, are to resist infection against bacteria and particularly against Neisseria, and to prevent immune complex disease. There are also undoubtedly balancing contributions to the pathogenesis of some infections and to all immune complex disease. Data from studies of C4 polymorphism and from the presence of control proteins on micro-organisms suggest there may be in addition more subtle contributions to immunity against a variety of other infections.

  2. Secondary metabolite signalling in host-parasitic plant interaction

    NARCIS (Netherlands)

    Bouwmeester, H.J.; Matusova, R.; Zhongkui, S.; Beale, M.H.

    2003-01-01

    The parasitic weeds Orobanche and Striga spp. are a serious threat to agriculture in large parts of the world. The lifecycle of the parasitic weeds is closely regulated by the presence of their hosts, and secondary metabolites that are produced by host plants play an important role in this

  3. Interactions between Trypanosoma cruzi Secreted Proteins and Host Cell Signaling Pathways

    Science.gov (United States)

    Watanabe Costa, Renata; da Silveira, Jose F.; Bahia, Diana

    2016-01-01

    Chagas disease is one of the prevalent neglected tropical diseases, affecting at least 6–7 million individuals in Latin America. It is caused by the protozoan parasite Trypanosoma cruzi, which is transmitted to vertebrate hosts by blood-sucking insects. After infection, the parasite invades and multiplies in the myocardium, leading to acute myocarditis that kills around 5% of untreated individuals. T. cruzi secretes proteins that manipulate multiple host cell signaling pathways to promote host cell invasion. The primary secreted lysosomal peptidase in T. cruzi is cruzipain, which has been shown to modulate the host immune response. Cruzipain hinders macrophage activation during the early stages of infection by interrupting the NF-kB P65 mediated signaling pathway. This allows the parasite to survive and replicate, and may contribute to the spread of infection in acute Chagas disease. Another secreted protein P21, which is expressed in all of the developmental stages of T. cruzi, has been shown to modulate host phagocytosis signaling pathways. The parasite also secretes soluble factors that exert effects on host extracellular matrix, such as proteolytic degradation of collagens. Finally, secreted phospholipase A from T. cruzi contributes to lipid modifications on host cells and concomitantly activates the PKC signaling pathway. Here, we present a brief review of the interaction between secreted proteins from T. cruzi and the host cells, emphasizing the manipulation of host signaling pathways during invasion. PMID:27065960

  4. Interactions between Trypanosoma cruzi secreted proteins and host cell signaling pathways

    Directory of Open Access Journals (Sweden)

    Renata Watanabe Costa

    2016-03-01

    Full Text Available Chagas disease is one of the prevalent neglected tropical diseases, affecting at least 6-7 million individuals in Latin America. It is caused by the protozoan parasite Trypanosoma cruzi (T. cruzi, which is transmitted to vertebrate hosts by blood-sucking insects. After infection, the parasite invades and multiplies in the myocardium, leading to acute myocarditis that kills around 5% of untreated individuals. T. cruzi secretes proteins that manipulate multiple host cell signaling pathways to promote host cell invasion. The primary secreted lysosomal peptidase in T. cruzi is cruzipain, which has been shown to modulate the host immune response. Cruzipain hinders macrophage activation during the early stages of infection by interrupting the NF-kB P65 mediated signaling pathway. This allows the parasite to survive and replicate, and may contribute to the spread of infection in acute Chagas disease. Another secreted protein P21, which is expressed in all of the developmental stages of T. cruzi, has been shown to modulate host phagocytosis signaling pathways. The parasite also secretes soluble factors that exert effects on host extracellular matrix, such as proteolytic degradation of collagens. Finally, secreted phospholipase A from T. cruzi contributes to lipid modifications on host cells and concomitantly activates the PKC signaling pathway. Here we present a brief review of the interaction between secreted proteins from T. cruzi and the host cells, emphasizing the manipulation of host signaling pathways during invasion.

  5. Identification of plant defence regulators through transcriptional ...

    Indian Academy of Sciences (India)

    2015-02-04

    Feb 4, 2015 ... The cdd1 mutant is constitutive for salicylic acid accumulation, signalling, and defence against biotrophic and hemibiotrophic pathogens, without having much impact on growth. Thus, cdd1 offers an ideal genetic background to identify novel regulators of plant defence. Here we report the differential gene.

  6. Mechanisms and ecological consequences of plant defence induction and suppression in herbivore communities

    Science.gov (United States)

    Kant, M. R.; Jonckheere, W.; Knegt, B.; Lemos, F.; Liu, J.; Schimmel, B. C. J.; Villarroel, C. A.; Ataide, L. M. S.; Dermauw, W.; Glas, J. J.; Egas, M.; Janssen, A.; Van Leeuwen, T.; Schuurink, R. C.; Sabelis, M. W.; Alba, J. M.

    2015-01-01

    Background Plants are hotbeds for parasites such as arthropod herbivores, which acquire nutrients and energy from their hosts in order to grow and reproduce. Hence plants are selected to evolve resistance, which in turn selects for herbivores that can cope with this resistance. To preserve their fitness when attacked by herbivores, plants can employ complex strategies that include reallocation of resources and the production of defensive metabolites and structures. Plant defences can be either prefabricated or be produced only upon attack. Those that are ready-made are referred to as constitutive defences. Some constitutive defences are operational at any time while others require activation. Defences produced only when herbivores are present are referred to as induced defences. These can be established via de novo biosynthesis of defensive substances or via modifications of prefabricated substances and consequently these are active only when needed. Inducibility of defence may serve to save energy and to prevent self-intoxication but also implies that there is a delay in these defences becoming operational. Induced defences can be characterized by alterations in plant morphology and molecular chemistry and are associated with a decrease in herbivore performance. These alterations are set in motion by signals generated by herbivores. Finally, a subset of induced metabolites are released into the air as volatiles and function as a beacon for foraging natural enemies searching for prey, and this is referred to as induced indirect defence. Scope The objective of this review is to evaluate (1) which strategies plants have evolved to cope with herbivores and (2) which traits herbivores have evolved that enable them to counter these defences. The primary focus is on the induction and suppression of plant defences and the review outlines how the palette of traits that determine induction/suppression of, and resistance/susceptibility of herbivores to, plant defences can

  7. Calcium signaling during the plant-plant interaction of parasitic Cuscuta reflexa with its hosts

    NARCIS (Netherlands)

    Albert, M.; Kaiser, B.; Krol, van der A.R.; Kaldenhoff, R.

    2010-01-01

    The plant parasite Cuscuta reflexa induces various responses in compatible and incompatible host plants. The visual reactions of both types of host plants including obvious morphological changes require the recognition of Cuscuta ssp. A consequently initiated signaling cascade is triggered which

  8. Shifting from priming of salicylic acid- to jasmonic acid-regulated defences by Trichoderma protects tomato against the root knot nematode Meloidogyne incognita.

    Science.gov (United States)

    Martínez-Medina, Ainhoa; Fernandez, Ivan; Lok, Gerrit B; Pozo, María J; Pieterse, Corné M J; Van Wees, Saskia C M

    2017-02-01

    Beneficial root endophytes such as Trichoderma spp. can reduce infections by parasitic nematodes through triggering host defences. Little is currently known about the complex hormone signalling underlying the induction of resistance. In this study, we investigated whether Trichoderma modulates the hormone signalling network in the host to induce resistance to nematodes. We investigated the role and the timing of the jasmonic acid (JA)- and salicylic acid (SA)-regulated defensive pathways in Trichoderma-induced resistance to the root knot nematode Meloidogyne incognita. A split-root system of tomato (Solanum lycopersicum) was used to study local and systemic induced defences by analysing nematode performance, defence gene expression, responsiveness to exogenous hormone application, and dependence on SA and JA signalling of Trichoderma-induced resistance. Root colonization by Trichoderma impeded nematode performance both locally and systemically at multiple stages of the parasitism, that is, invasion, galling and reproduction. First, Trichoderma primed SA-regulated defences, which limited nematode root invasion. Then, Trichoderma enhanced JA-regulated defences, thereby antagonizing the deregulation of JA-dependent immunity by the nematodes, which compromised galling and fecundity. Our results show that Trichoderma primes SA- and JA-dependent defences in roots, and that the priming of responsiveness to these hormones upon nematode attack is plastic and adaptive to the parasitism stage. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

  9. Signal molecules mediate the impact of the earthworm Aporrectodea caliginosa on growth, development and defence of the plant Arabidopsis thaliana.

    Directory of Open Access Journals (Sweden)

    Ruben Puga-Freitas

    Full Text Available Earthworms have generally a positive impact on plant growth, which is often attributed to a trophic mechanism: namely, earthworms increase the release of mineral nutrients from soil litter and organic matter. An alternative hypothesis has been proposed since the discovery of a signal molecule (Indole Acetic Acid in earthworm faeces. In this study, we used methodologies developed in plant science to gain information on ecological mechanisms involved in plant-earthworm interaction, by looking at plant response to earthworm presence at a molecular level. First, we looked at plant overall response to earthworm faeces in an in vitro device where only signal molecules could have an effect on plant growth; we observed that earthworms were inducing positive or negative effects on different plant species. Then, using an Arabidopsis thaliana mutant with an impaired auxin transport, we demonstrated the potential of earthworms to stimulate root growth and to revert the dwarf mutant phenotype. Finally, we performed a comparative transcriptomic analysis of Arabidopsis thaliana in the presence and absence of earthworms; we found that genes modulated in the presence of earthworms are known to respond to biotic and abiotic stresses, or to the application of exogenous hormones. A comparison of our results with other studies found in databases revealed strong analogies with systemic resistance, induced by signal molecules emitted by Plant Growth Promoting Rhizobacteria and/or elicitors emitted by non-virulent pathogens. Signal molecules such as auxin and ethylene, which are considered as major in plant-microorganisms interactions, can also be of prior importance to explain plant-macroinvertebrates interactions. This could imply revisiting ecological theories which generally stress on the role of trophic relationships.

  10. Signal Molecules Mediate the Impact of the Earthworm Aporrectodea caliginosa on Growth, Development and Defence of the Plant Arabidopsis thaliana

    Science.gov (United States)

    Puga-Freitas, Ruben; Barot, Sébastien; Taconnat, Ludivine; Renou, Jean-Pierre; Blouin, Manuel

    2012-01-01

    Earthworms have generally a positive impact on plant growth, which is often attributed to a trophic mechanism: namely, earthworms increase the release of mineral nutrients from soil litter and organic matter. An alternative hypothesis has been proposed since the discovery of a signal molecule (Indole Acetic Acid) in earthworm faeces. In this study, we used methodologies developed in plant science to gain information on ecological mechanisms involved in plant-earthworm interaction, by looking at plant response to earthworm presence at a molecular level. First, we looked at plant overall response to earthworm faeces in an in vitro device where only signal molecules could have an effect on plant growth; we observed that earthworms were inducing positive or negative effects on different plant species. Then, using an Arabidopsis thaliana mutant with an impaired auxin transport, we demonstrated the potential of earthworms to stimulate root growth and to revert the dwarf mutant phenotype. Finally, we performed a comparative transcriptomic analysis of Arabidopsis thaliana in the presence and absence of earthworms; we found that genes modulated in the presence of earthworms are known to respond to biotic and abiotic stresses, or to the application of exogenous hormones. A comparison of our results with other studies found in databases revealed strong analogies with systemic resistance, induced by signal molecules emitted by Plant Growth Promoting Rhizobacteria and/or elicitors emitted by non-virulent pathogens. Signal molecules such as auxin and ethylene, which are considered as major in plant-microorganisms interactions, can also be of prior importance to explain plant-macroinvertebrates interactions. This could imply revisiting ecological theories which generally stress on the role of trophic relationships. PMID:23226498

  11. A tritrophic signal that attracts parasitoids to host-damaged plants withstands disruption by non-host herbivores

    Directory of Open Access Journals (Sweden)

    Turlings Ted CJ

    2010-11-01

    Full Text Available Abstract Background Volatiles emitted by herbivore-infested plants are highly attractive to parasitoids and therefore have been proposed to be part of an indirect plant defense strategy. However, this proposed function of the plant-provided signals remains controversial, and it is unclear how specific and reliable the signals are under natural conditions with simultaneous feeding by multiple herbivores. Phloem feeders in particular are assumed to interfere with plant defense responses. Therefore, we investigated how attack by the piercing-sucking cicadellid Euscelidius variegatus influences signaling by maize plants in response to the chewing herbivore Spodoptera littoralis. Results The parasitoid Cotesia marginiventris strongly preferred volatiles of plants infested with its host S. littoralis. Overall, the volatile emissions induced by S. littoralis and E. variegatus were similar, but higher levels of certain wound-released compounds may have allowed the wasps to specifically recognize plants infested by hosts. Expression levels of defense marker genes and further behavioral bioassays with the parasitoid showed that neither the physiological defense responses nor the attractiveness of S. littoralis infested plants were altered by simultaneous E. variegatus attack. Conclusions Our findings imply that plant defense responses to herbivory can be more robust than generally assumed and that ensuing volatiles convey specific information about the type of herbivore that is attacking a plant, even in complex situations with multiple herbivores. Hence, the results of this study support the notion that herbivore-induced plant volatiles may be part of a plant's indirect defense stratagem.

  12. Multiple Signal Classification (MUSIC) Algorithm Hosted On The High Speed Systolic Array Processor (HISSAP)

    Science.gov (United States)

    Loughlin, Joseph P.

    1989-12-01

    A direction of arrival estimator based on the MUSIC algorithm hosted on a microprogrammed systolic array processor testbed system will be presented. The mapping approach is discussed and the major parts of the algorithm demonstration application are identified. The impact of manipulating complex sample data within the MUSIC algorithm is also discussed. The use of parallel programming tools custom built to translate, debug and evaluate systolically hosted signal processing algorithms will be described.

  13. Activation and interruption of the reproduction of Varroa destructor is triggered by host signals (Apis mellifera).

    Science.gov (United States)

    Frey, Eva; Odemer, Richard; Blum, Thomas; Rosenkranz, Peter

    2013-05-01

    The reproductive cycle of the parasitic mite Varroa destructor is closely linked to the development of the honey bee host larvae. Using a within colony approach we introduced phoretic Varroa females into brood cells of different age in order to analyze the capacity of certain stages of the honey bee larva to either activate or interrupt the reproduction of Varroa females. Only larvae within 18 h (worker) and 36 h (drones), respectively, after cell capping were able to stimulate the mite's oogenesis. Therewith we could specify for the first time the short time window where honey bee larvae provide the signals for the activation of the Varroa reproduction. Stage specific volatiles of the larval cuticle are at least part of these activation signals. This is confirmed by the successful stimulation of presumably non-reproducing mites to oviposition by the application of a larval extract into the sealed brood cells. According to preliminary quantitative GC-MS analysis we suggest certain fatty acid ethyl esters as candidate compounds. If Varroa females that have just started with egg formation are transferred to brood cells containing host larvae of an elder stage two-thirds of these mites stopped their oogenesis. This confirms the presence of an additional signal in the host larvae allowing the reproducing mites to adjust their own reproductive cycle to the ontogenetic development of the host. From an adaptive point of view that sort of a stop signal enables the female mite to save resources for a next reproductive cycle if the own egg development is not sufficiently synchronized with the development of the host. The results presented here offer the opportunity to analyze exactly those host stages that have the capacity to activate or interrupt the Varroa reproduction in order to identify the crucial host signals. Copyright © 2013 Elsevier Inc. All rights reserved.

  14. Oxidative stress in fungi: its function in signal transduction, interaction with plant hosts, and lignocellulose degradation.

    Science.gov (United States)

    Breitenbach, Michael; Weber, Manuela; Rinnerthaler, Mark; Karl, Thomas; Breitenbach-Koller, Lore

    2015-04-03

    In this review article, we want to present an overview of oxidative stress in fungal cells in relation to signal transduction, interaction of fungi with plant hosts, and lignocellulose degradation. We will discuss external oxidative stress which may occur through the interaction with other microorganisms or plant hosts as well as internally generated oxidative stress, which can for instance originate from NADPH oxidases or "leaky" mitochondria and may be modulated by the peroxiredoxin system or by protein disulfide isomerases thus contributing to redox signaling. Analyzing redox signaling in fungi with the tools of molecular genetics is presently only in its beginning. However, it is already clear that redox signaling in fungal cells often is linked to cell differentiation (like the formation of perithecia), virulence (in plant pathogens), hyphal growth and the successful passage through the stationary phase.

  15. Oxidative Stress in Fungi: Its Function in Signal Transduction, Interaction with Plant Hosts, and Lignocellulose Degradation

    Directory of Open Access Journals (Sweden)

    Michael Breitenbach

    2015-04-01

    Full Text Available In this review article, we want to present an overview of oxidative stress in fungal cells in relation to signal transduction, interaction of fungi with plant hosts, and lignocellulose degradation. We will discuss external oxidative stress which may occur through the interaction with other microorganisms or plant hosts as well as internally generated oxidative stress, which can for instance originate from NADPH oxidases or “leaky” mitochondria and may be modulated by the peroxiredoxin system or by protein disulfide isomerases thus contributing to redox signaling. Analyzing redox signaling in fungi with the tools of molecular genetics is presently only in its beginning. However, it is already clear that redox signaling in fungal cells often is linked to cell differentiation (like the formation of perithecia, virulence (in plant pathogens, hyphal growth and the successful passage through the stationary phase.

  16. Salicylic acid-independent plant defence pathways

    NARCIS (Netherlands)

    Pieterse, C.M.J.; Loon, L.C. van

    1999-01-01

    Salicylic acid is an important signalling molecule involved in both locally and systemically induced disease resistance responses. Recent advances in our understanding of plant defence signalling have revealed that plants employ a network of signal transduction pathways, some of which are

  17. The influence of host hormones and cytokines on Echinococcus multilocularis signalling and development

    Directory of Open Access Journals (Sweden)

    Brehm K.

    2008-09-01

    Full Text Available Parasitic helminths display highly complex life-cycles in which the establishment of adults or larvae within host target organs as well as the transition of one developmental stage to the following is influenced by host-derived factors. Due to its approachability concerning in vitro cultivation, the larval stage of the fox-tapeworm Echinococcus multilocularis has recently emerged as a model system to study the molecular nature of such host-derived stimuli and their influence on developmental control in the parasite. Data obtained so far indicate that cytokines which are used by the host for cell-cell communication can also be exploited by the parasite as clues to find suitable target organs. This involves direct interactions of evolutionary conserved signalling systems of the receptor tyrosine – and the receptor serine/threonine-kinase pathways of the parasite with corresponding host cytokines of the insulin –, the epidermal growth factor-, and the transforming growth factor-β-families. In the present article, we will briefly review in vitro cultivation approaches undertaken so far for E. multilocularis larvae as well as our current knowledge on the parasite’s signalling systems and their interaction with host cytokines.

  18. The trans-generational impact of population density signals on host-parasite interactions.

    Science.gov (United States)

    Michel, Jessica; Ebert, Dieter; Hall, Matthew D

    2016-11-25

    The density of a host population is a key parameter underlying disease transmission, but it also has implications for the expression of disease through its effect on host physiology. In response to higher densities, individuals are predicted to either increase their immune investment in response to the elevated risk of parasitism, or conversely to decrease their immune capacity as a consequence of the stress of a crowded environment. However, an individual's health is shaped by many different factors, including their genetic background, current environmental conditions, and maternal effects. Indeed, population density is often sensed through the presence of info-chemicals in the environment, which may influence a host's interaction with parasites, and also those of its offspring. All of which may alter the expression of disease, and potentially uncouple the presumed link between changes in host density and disease outcomes. In this study, we used the water flea Daphnia magna and its obligate bacterial parasite Pasteuria ramosa, to investigate how signals of high host density impact on host-parasite interactions over two consecutive generations. We found that the chemical signals from crowded treatments induced phenotypic changes in both the parental and offspring generations. In the absence of a pathogen, life-history changes were genotype-specific, but consistent across generations, even when the signal of density was removed. In contrast, the influence of density on infected animals depended on the trait and generation of exposure. When directly exposed to signals of high-density, host genotypes responded differently in how they minimised the severity of disease. Yet, in the subsequent generation, the influence of density was rarely genotype-specific and instead related to ability of the host to minimise the onset of infection. Our findings reveal that population level correlations between host density and infection capture only part of the complex relationship

  19. Drosophila microbiome modulates host developmental and metabolic homeostasis via insulin signaling.

    Science.gov (United States)

    Shin, Seung Chul; Kim, Sung-Hee; You, Hyejin; Kim, Boram; Kim, Aeri C; Lee, Kyung-Ah; Yoon, Joo-Heon; Ryu, Ji-Hwan; Lee, Won-Jae

    2011-11-04

    The symbiotic microbiota profoundly affect many aspects of host physiology; however, the molecular mechanisms underlying host-microbe cross-talk are largely unknown. Here, we show that the pyrroloquinoline quinone-dependent alcohol dehydrogenase (PQQ-ADH) activity of a commensal bacterium, Acetobacter pomorum, modulates insulin/insulin-like growth factor signaling (IIS) in Drosophila to regulate host homeostatic programs controlling developmental rate, body size, energy metabolism, and intestinal stem cell activity. Germ-free animals monoassociated with PQQ-ADH mutant bacteria displayed severe deregulation of developmental and metabolic homeostasis. Importantly, these defects were reversed by enhancing host IIS or by supplementing the diet with acetic acid, the metabolic product of PQQ-ADH.

  20. Drosophila Microbiota Modulates Host Metabolic Gene Expression via IMD/NF-κB Signaling

    Science.gov (United States)

    Bozonnet, Noémie; Puthier, Denis; Royet, Julien; Leulier, François

    2014-01-01

    Most metazoans engage in mutualistic interactions with their intestinal microbiota. Despite recent progress the molecular mechanisms through which microbiota exerts its beneficial influences on host physiology are still largely uncharacterized. Here we use axenic Drosophila melanogaster adults associated with a standardized microbiota composed of a defined set of commensal bacterial strains to study the impact of microbiota association on its host transcriptome. Our results demonstrate that Drosophila microbiota has a marked impact on the midgut transcriptome and promotes the expression of genes involved in host digestive functions and primary metabolism. We identify the IMD/Relish signaling pathway as a central regulator of this microbiota-mediated transcriptional response and we reveal a marked transcriptional trade-off between the midgut response to its beneficial microbiota and to bacterial pathogens. Taken together our results indicate that microbiota association potentiates host nutrition and host metabolic state, two key physiological parameters influencing host fitness. Our work paves the way to subsequent mechanistic studies to reveal how these microbiota-dependent transcriptional signatures translate into host physiological benefits. PMID:24733183

  1. CXCR2 signaling and host defense following coronavirus-induced encephalomyelitis.

    Science.gov (United States)

    Marro, Brett S; Hosking, Martin P; Lane, Thomas E

    2012-04-01

    Inoculation of the neurotropic JHM strain of mouse hepatitis virus (JHMV) into the central nervous system (CNS) of susceptible strains of mice results in wide-spread replication within glial cells accompanied by infiltration of virus-specific T lymphocytes that control virus through cytokine secretion and cytolytic activity. Virus persists within white matter tracts of surviving mice resulting in demyelination that is amplified by inflammatory T cells and macrophages. In response to infection, numerous cytokines/chemokines are secreted by resident cells of the CNS and inflammatory leukocytes that participate in both host defense and disease. Among these are the ELR-positive chemokines that are able to signal through CXC chemokine receptors including CXCR2. Early following JHMV infection, ELR-positive chemokines contribute to host defense by attracting CXCR2-expressing cells including polymorphonuclear cells to the CNS that aid in host defense through increasing the permeability the blood-brain-barrier (BBB). During chronic disease, CXCR2 signaling on oligodendroglia protects these cells from apoptosis and restricts the severity of demyelination. This review covers aspects related to host defense and disease in response to JHMV infection and highlights the different roles of CXCR2 signaling in these processes.

  2. Lack of clinical manifestations in asymptomatic dengue infection is attributed to broad down-regulation and selective up-regulation of host defence response genes.

    Directory of Open Access Journals (Sweden)

    Adeline S L Yeo

    Full Text Available OBJECTIVES: Dengue represents one of the most serious life-threatening vector-borne infectious diseases that afflicts approximately 50 million people across the globe annually. Whilst symptomatic infections are frequently reported, asymptomatic dengue remains largely unnoticed. Therefore, we sought to investigate the immune correlates conferring protection to individuals that remain clinically asymptomatic. METHODS: We determined the levels of neutralizing antibodies (nAbs and gene expression profiles of host immune factors in individuals with asymptomatic infections, and whose cognate household members showed symptoms consistent to clinical dengue infection. RESULTS: We observed broad down-regulation of host defense response (innate, adaptive and matrix metalloprotease genes in asymptomatic individuals as against symptomatic patients, with selective up-regulation of distinct genes that have been associated with protection. Selected down-regulated genes include: TNF α (TNF, IL8, C1S, factor B (CFB, IL2, IL3, IL4, IL5, IL8, IL9, IL10 and IL13, CD80, CD28, and IL18, MMP8, MMP10, MMP12, MMP15, MMP16, and MMP24. Selected up-regulated genes include: RANTES (CCL5, MIP-1α (CCL3L1/CCL3L3, MIP-1β (CCL4L1, TGFβ (TGFB, and TIMP1. CONCLUSION: Our findings highlight the potential association of certain host genes conferring protection against clinical dengue. These data are valuable to better explore the mysteries behind the hitherto poorly understood immunopathogenesis of subclinical dengue infection.

  3. Infection of goats with goatpox virus triggers host antiviral defense through activation of innate immune signaling.

    Science.gov (United States)

    Zeng, Xiancheng; Wang, Song; Chi, Xiaojuan; Chen, Shi-long; Huang, Shile; Lin, Qunqun; Xie, Baogui; Chen, Ji-Long

    2016-02-01

    Goatpox, caused by goatpox virus (GTPV), is one of the most serious infectious diseases associated with high morbidity and mortality in goats. However, little is known about involvement of host innate immunity during the GTPV infection. For this, goats were experimentally infected with GTPV. The results showed that GTPV infection significantly induced mRNA expression of type I interferon (IFN)-α and IFN-β in peripheral blood lymphocytes, spleen and lung. In addition, GTPV infection enhanced expression of several inflammatory cytokines, including interleukin (IL)-1β, IL-6, IL-18; and tumor necrosis factor-α (TNF-α). Strikingly, infection with GTPV activated signal transducers and activators of transcription 3 (STAT3), a critical cytokine signaling molecule. Interestingly, the virus infection induced expression of suppressor of cytokine signaling (SOCS)-1. Importantly, the infection resulted in an increased expression of some critical interferon-stimulated genes, such as interferon-induced transmembrane protein (IFITM) 1, IFITM3, interferon stimulated gene (ISG) 15 and ISG20. Furthermore, we found that infection with GTPV up-regulated expression of Toll-like receptor (TLR) 2 and TLR9. These results revealed that GTPV infection activated host innate immune signaling and thereby triggered antiviral innate immunity. The findings provide novel insights into complex mechanisms underlying GTPV-host interaction and pathogenesis of GTPV. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Timing of fungal invasion using host's ripening hormone as a signal.

    Science.gov (United States)

    Flaishman, M A; Kolattukudy, P E

    1994-07-05

    In many postharvest fruit diseases, fungi remain latent until the fruit ripens. How the fungus times its infection at ripening of the host is not known. We have found that the volatiles produced by the climacteric tomato, avocado, and banana fruits induce germination and appressorium formation in Colletotrichum gloeosporioides and Colletotrichum musae. Exposure of the spores of these fungi to ethylene, the host's ripening hormone, at transgenic tomato and orange, fruits incapable of producing ethylene, exogenous ethylene was required to induce multiple appressorium formation and lesion formation. These results strongly suggest that these fungi must have coevolved to develop a mechanism to use the host's ripening hormone as a signal to differentiate into multiple infection structure and thus time the infection process.

  5. Rhizobial peptidase HrrP cleaves host-encoded signaling peptides and mediates symbiotic compatibility.

    Science.gov (United States)

    Price, Paul A; Tanner, Houston R; Dillon, Brett A; Shabab, Mohammed; Walker, Graham C; Griffitts, Joel S

    2015-12-08

    Legume-rhizobium pairs are often observed that produce symbiotic root nodules but fail to fix nitrogen. Using the Sinorhizobium meliloti and Medicago truncatula symbiotic system, we previously described several naturally occurring accessory plasmids capable of disrupting the late stages of nodule development while enhancing bacterial proliferation within the nodule. We report here that host range restriction peptidase (hrrP), a gene found on one of these plasmids, is capable of conferring both these properties. hrrP encodes an M16A family metallopeptidase whose catalytic activity is required for these symbiotic effects. The ability of hrrP to suppress nitrogen fixation is conditioned upon the genotypes of both the host plant and the hrrP-expressing rhizobial strain, suggesting its involvement in symbiotic communication. Purified HrrP protein is capable of degrading a range of nodule-specific cysteine-rich (NCR) peptides encoded by M. truncatula. NCR peptides are crucial signals used by M. truncatula for inducing and maintaining rhizobial differentiation within nodules, as demonstrated in the accompanying article [Horváth B, et al. (2015) Proc Natl Acad Sci USA, 10.1073/pnas.1500777112]. The expression pattern of hrrP and its effects on rhizobial morphology are consistent with the NCR peptide cleavage model. This work points to a symbiotic dialogue involving a complex ensemble of host-derived signaling peptides and bacterial modifier enzymes capable of adjusting signal strength, sometimes with exploitative outcomes.

  6. Sensory Protein Kinase Signaling in Schistosoma mansoni Cercariae: Host Location and Invasion.

    Science.gov (United States)

    Ressurreição, Margarida; Kirk, Ruth S; Rollinson, David; Emery, Aidan M; Page, Nigel M; Walker, Anthony J

    2015-12-01

    Schistosoma mansoni cercariae display specific behavioral responses to abiotic/biotic stimuli enabling them to locate and infect the definitive human host. Here we report the effect of such stimulants on signaling pathways of cercariae in relation to host finding and invasion. Cercariae exposed to various light/temperature regimens displayed modulated protein kinase C (PKC), extracellular signal-regulated kinase (ERK) and p38 mitogen-activated protein kinase (p38 MAPK) activities, with distinct responses at 37 °C and intense light/dark, when compared to 24 °C under normal light. Kinase activities were localized to regions including the oral sensory papillae, acetabular ducts, tegument, acetabular glands, and nervous system. Furthermore, linoleic acid modulated PKC and ERK activities concurrent with the temporal release of acetabular gland components. Attenuation of PKC, ERK, and p38 MAPK activities significantly reduced gland component release, particularly in response to linoleic acid, demonstrating the importance of these signaling pathways to host penetration mechanisms. © The Author 2015. Published by Oxford University Press on behalf of the Infectious Diseases Society of America.

  7. Cellular stress response and innate immune signaling: integrating pathways in host defense and inflammation

    Science.gov (United States)

    Muralidharan, Sujatha; Mandrekar, Pranoti

    2013-01-01

    Extensive research in the past decade has identified innate immune recognition receptors and intracellular signaling pathways that culminate in inflammatory responses. Besides its role in cytoprotection, the importance of cell stress in inflammation and host defense against pathogens is emerging. Recent studies have shown that proteins in cellular stress responses, including the heat shock response, ER stress response, and DNA damage response, interact with and regulate signaling intermediates involved in the activation of innate and adaptive immune responses. The effect of such regulation by cell stress proteins may dictate the inflammatory profile of the immune response during infection and disease. In this review, we describe the regulation of innate immune cell activation by cell stress pathways, present detailed descriptions of the types of stress response proteins and their crosstalk with immune signaling intermediates that are essential in host defense, and illustrate the relevance of these interactions in diseases characteristic of aberrant immune responses, such as chronic inflammatory diseases, autoimmune disorders, and cancer. Understanding the crosstalk between cellular stress proteins and immune signaling may have translational implications for designing more effective regimens to treat immune disorders. PMID:23990626

  8. Pathogenic Leptospires Modulate Protein Expression and Post-translational Modifications in Response to Mammalian Host Signals.

    Science.gov (United States)

    Nally, Jarlath E; Grassmann, Andre A; Planchon, Sébastien; Sergeant, Kjell; Renaut, Jenny; Seshu, Janakiram; McBride, Alan J; Caimano, Melissa J

    2017-01-01

    Pathogenic species of Leptospira cause leptospirosis, a bacterial zoonotic disease with a global distribution affecting over one million people annually. Reservoir hosts of leptospirosis, including rodents, dogs, and cattle, exhibit little to no signs of disease but shed large numbers of organisms in their urine. Transmission occurs when mucosal surfaces or abraded skin come into contact with infected urine or urine-contaminated water or soil. Whilst little is known about how Leptospira adapt to and persist within a reservoir host, in vitro studies suggest that leptospires alter their transcriptomic and proteomic profiles in response to environmental signals encountered during mammalian infection. We applied the dialysis membrane chamber (DMC) peritoneal implant model to compare the whole cell proteome of in vivo derived leptospires with that of leptospires cultivated in vitro at 30°C and 37°C by 2-dimensional difference in-gel electrophoresis (2-D DIGE). Of 1,735 protein spots aligned across 9 2-D DIGE gels, 202 protein spots were differentially expressed (p 1.25 or proteins were excised for identification by mass spectrometry. Data are available via ProteomeXchange with identifier PXD006995. The greatest differences were detected when DMC-cultivated leptospires were compared with IV30- or IV37-cultivated leptospires, including the increased expression of multiple isoforms of Loa22, a known virulence factor. Unexpectedly, 20 protein isoforms of LipL32 and 7 isoforms of LipL41 were uniformly identified by DIGE as differentially expressed, suggesting that unique post-translational modifications (PTMs) are operative in response to mammalian host conditions. To test this hypothesis, a rat model of persistent renal colonization was used to isolate leptospires directly from the urine of experimentally infected rats. Comparison of urinary derived leptospires to IV30 leptospires by 2-D immunoblotting confirmed that modification of proteins with trimethyllysine and

  9. Pathogenic Leptospires Modulate Protein Expression and Post-translational Modifications in Response to Mammalian Host Signals

    Directory of Open Access Journals (Sweden)

    Jarlath E. Nally

    2017-08-01

    Full Text Available Pathogenic species of Leptospira cause leptospirosis, a bacterial zoonotic disease with a global distribution affecting over one million people annually. Reservoir hosts of leptospirosis, including rodents, dogs, and cattle, exhibit little to no signs of disease but shed large numbers of organisms in their urine. Transmission occurs when mucosal surfaces or abraded skin come into contact with infected urine or urine-contaminated water or soil. Whilst little is known about how Leptospira adapt to and persist within a reservoir host, in vitro studies suggest that leptospires alter their transcriptomic and proteomic profiles in response to environmental signals encountered during mammalian infection. We applied the dialysis membrane chamber (DMC peritoneal implant model to compare the whole cell proteome of in vivo derived leptospires with that of leptospires cultivated in vitro at 30°C and 37°C by 2-dimensional difference in-gel electrophoresis (2-D DIGE. Of 1,735 protein spots aligned across 9 2-D DIGE gels, 202 protein spots were differentially expressed (p < 0.05, fold change >1.25 or < −1.25 across all three conditions. Differentially expressed proteins were excised for identification by mass spectrometry. Data are available via ProteomeXchange with identifier PXD006995. The greatest differences were detected when DMC-cultivated leptospires were compared with IV30- or IV37-cultivated leptospires, including the increased expression of multiple isoforms of Loa22, a known virulence factor. Unexpectedly, 20 protein isoforms of LipL32 and 7 isoforms of LipL41 were uniformly identified by DIGE as differentially expressed, suggesting that unique post-translational modifications (PTMs are operative in response to mammalian host conditions. To test this hypothesis, a rat model of persistent renal colonization was used to isolate leptospires directly from the urine of experimentally infected rats. Comparison of urinary derived leptospires to IV30

  10. Systems approach to characterizing cell signaling in host-pathogen response to staphylococcus toxin.

    Energy Technology Data Exchange (ETDEWEB)

    Ambrosiano, J. J. (John J.); Gupta, G. (Goutam); Gray, P. C. (Perry C.); Hush, D. R. (Donald R.); Fugate, M. L. (Michael L.); Cleland, T. J. (Timothy J.); Roberts, R. M. (Randy M.); Hlavacek, W. S. (William S.); Smith, J. L. (Jessica L.)

    2002-01-01

    The mammalian immune system is capable of highly sensitive and specific responses when challenged by pathogens. It is believed that the human immune repertoire - the total number of distinct antigens that can be recognized - is between 10{sup 9} and 10{sup 11}. The most specific responses are cell mediated and involve complex and subtle communications among the immune cells via small proteins known as cytokines. The details of host-pathogen response are exceedingly complex, involving both intracellular and extracellular mechanisms. These include the presentation of antigen by B cells to helper T cells and subsequent stimulation of signal transduction pathways and gene expression within both B and T-cell populations. These in turn lead to the secretion of cytokines and receptor expression. Intercellular cytokine signaling can trigger a host of immune responses including the proliferation and specialization of naive immune cells and the marshaling of effector cells to combat infection. In the ever-evolving game of threat and countermeasure played out by pathogens and their intended hosts, there are direct assaults aimed at subverting the immune system's ability to recognize antigens and respond effectively to challenge by pathogens. Staphylococcus is one of these. Staph bacteria secrete a variety of toxins known generically as superantigens. Superantigen molecules bind simultaneously to the MHC receptors of antigen presenting cells and the TCR receptors of helper T cells, locking them in place and leading to overstimulation. This strategy can effectively burn out the immune system in a matter of days.

  11. Honeybee gut microbiota promotes host weight gain via bacterial metabolism and hormonal signaling

    Science.gov (United States)

    Powell, J. Elijah; Steele, Margaret I.; Dietrich, Carsten; Moran, Nancy A.

    2017-01-01

    Social bees harbor a simple and specialized microbiota that is spatially organized into different gut compartments. Recent results on the potential involvement of bee gut communities in pathogen protection and nutritional function have drawn attention to the impact of the microbiota on bee health. However, the contributions of gut microbiota to host physiology have yet to be investigated. Here we show that the gut microbiota promotes weight gain of both whole body and the gut in individual honey bees. This effect is likely mediated by changes in host vitellogenin, insulin signaling, and gustatory response. We found that microbial metabolism markedly reduces gut pH and redox potential through the production of short-chain fatty acids and that the bacteria adjacent to the gut wall form an oxygen gradient within the intestine. The short-chain fatty acid profile contributed by dominant gut species was confirmed in vitro. Furthermore, metabolomic analyses revealed that the gut community has striking impacts on the metabolic profiles of the gut compartments and the hemolymph, suggesting that gut bacteria degrade plant polymers from pollen and that the resulting metabolites contribute to host nutrition. Our results demonstrate how microbial metabolism affects bee growth, hormonal signaling, behavior, and gut physicochemical conditions. These findings indicate that the bee gut microbiota has basic roles similar to those found in some other animals and thus provides a model in studies of host–microbe interactions. PMID:28420790

  12. Molecular Signaling Involved in Entry and Exit of Malaria Parasites from Host Erythrocytes.

    Science.gov (United States)

    Singh, Shailja; Chitnis, Chetan E

    2017-10-03

    During the blood stage, Plasmodium spp. merozoites invade host red blood cells (RBCs), multiply, exit, and reinvade uninfected RBCs in a continuing cycle that is responsible for all the clinical symptoms associated with malaria. Entry into (invasion) and exit from (egress) RBCs are highly regulated processes that are mediated by an array of parasite proteins with specific functional roles. Many of these parasite proteins are stored in specialized apical secretory vesicles, and their timely release is critical for successful invasion and egress. For example, the discharge of parasite protein ligands to the apical surface of merozoites is required for interaction with host receptors to mediate invasion, and the timely discharge of proteases and pore-forming proteins helps in permeabilization and dismantling of limiting membranes during egress. This review focuses on our understanding of the signaling mechanisms that regulate apical organelle secretion during host cell invasion and egress by malaria parasites. The review also explores how understanding key signaling mechanisms in the parasite can open opportunities to develop novel strategies to target Plasmodium parasites and eliminate malaria. Copyright © 2017 Cold Spring Harbor Laboratory Press; all rights reserved.

  13. Defence White Paper 2013

    Science.gov (United States)

    2013-01-01

    domestic developments since 2009, which influence Australia’s national security and defence settings, including their impact on force posture, future...Financial Crisis, which have continued to see a significant deleterious impact on the global economy, domestic fiscal circumstances and Defence funding...these trends are shaping the emergence of the Indo-Pacific as a single strategic arc. 1.13 Globalisation and new technologies are increasing the

  14. Defence Test and Evaluation Roadmap

    Science.gov (United States)

    2008-01-01

    development of a centralised and coordinated approach to Defence’s T&E resources and priorities; a proposed T&E framework that considers T&E at the system...main reviews and reports that provide strategic guidance and highlight the importance of T&E for Defence. They are the: Defence Procurement Review...Affairs, Defence and Trade References Committee, March 2003. Defence Procurement Review 2003 The Defence Procurement Review 2003, commonly known as the

  15. Anomaly Detection in Host Signaling Pathways for the Early Prognosis of Acute Infection.

    Science.gov (United States)

    Wang, Kun; Langevin, Stanley; O'Hern, Corey S; Shattuck, Mark D; Ogle, Serenity; Forero, Adriana; Morrison, Juliet; Slayden, Richard; Katze, Michael G; Kirby, Michael

    2016-01-01

    diagnostic tools to distinguish between acute viral and bacterial respiratory infections is critical to improve patient care and limit the overuse of antibiotics in the medical community. The identification of prognostic respiratory virus biomarkers provides an early warning system that is capable of predicting which subjects will become symptomatic to expand our medical diagnostic capabilities and treatment options for acute infectious diseases. The host response to acute infection may be viewed as a deterministic signaling network responsible for maintaining the health of the host organism. We identify pathway signatures that reflect the very earliest perturbations in the host response to acute infection. These pathways provide a monitor the health state of the host using anomaly detection to quantify and predict health outcomes to pathogens.

  16. Anomaly Detection in Host Signaling Pathways for the Early Prognosis of Acute Infection.

    Directory of Open Access Journals (Sweden)

    Kun Wang

    development of clinical diagnostic tools to distinguish between acute viral and bacterial respiratory infections is critical to improve patient care and limit the overuse of antibiotics in the medical community. The identification of prognostic respiratory virus biomarkers provides an early warning system that is capable of predicting which subjects will become symptomatic to expand our medical diagnostic capabilities and treatment options for acute infectious diseases. The host response to acute infection may be viewed as a deterministic signaling network responsible for maintaining the health of the host organism. We identify pathway signatures that reflect the very earliest perturbations in the host response to acute infection. These pathways provide a monitor the health state of the host using anomaly detection to quantify and predict health outcomes to pathogens.

  17. Understanding plant defence responses against herbivore attacks: an essential first step towards the development of sustainable resistance against pests.

    Science.gov (United States)

    Santamaria, M Estrella; Martínez, Manuel; Cambra, Inés; Grbic, Vojislava; Diaz, Isabel

    2013-08-01

    Plant-herbivore relationships are complex interactions encompassing elaborate networks of molecules, signals and strategies used to overcome defences developed by each other. Herbivores use multiple feeding strategies to obtain nutrients from host plants. In turn, plants respond by triggering defence mechanisms to inhibit, block or modify the metabolism of the pest. As part of these defences, herbivore-challenged plants emit volatiles to attract natural enemies and warn neighbouring plants of the imminent threat. In response, herbivores develop a variety of strategies to suppress plant-induced protection. Our understanding of the plant-herbivore interphase is limited, although recent molecular approaches have revealed the participation of a battery of genes, proteins and volatile metabolites in attack-defence processes. This review describes the intricate and dynamic defence systems governing plant-herbivore interactions by examining the diverse strategies plants employ to deny phytophagous arthropods the ability to breach newly developed mechanisms of plant resistance. A cornerstone of this understanding is the use of transgenic tools to unravel the complex networks that control these interactions.

  18. DMPD: Regulation of TLR4 signaling and the host interface with pathogens and danger:the role of RP105. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 17470533 Regulation of TLR4 signaling and the host interface with pathogens and dan...tion of TLR4 signaling and the host interface with pathogens and danger:the role ...of RP105. PubmedID 17470533 Title Regulation of TLR4 signaling and the host interface with pathogens and dan

  19. Trichoderma Biocontrol: Signal Transduction Pathways Involved in Host Sensing and Mycoparasitism

    Directory of Open Access Journals (Sweden)

    Susanne Zeilinger

    2007-01-01

    Full Text Available Fungi of the genus Trichoderma are used as biocontrol agents against several plant pathogenic fungi like Rhizoctonia spp., Pythium spp., Botrytis cinerea and Fusarium spp. which cause both soil-borne and leaf- or flower-borne diseases of agricultural plants. Plant disease control by Trichoderma is based on complex interactions between Trichoderma, the plant pathogen and the plant. Until now, two main components of biocontrol have been identified: direct activity of Trichoderma against the plant pathogen by mycoparasitism and induced systemic resistance in plants. As the mycoparasitic interaction is host-specific and not merely a contact response, it is likely that signals from the host fungus are recognised by Trichoderma and provoke transcription of mycoparasitism-related genes.In the last few years examination of signalling pathways underlying Trichoderma biocontrol started and it was shown that heterotrimeric G-proteins and mitogen-activated protein (MAP kinases affected biocontrol-relevant processes such as the production of hydrolytic enzymes and antifungal metabolites and the formation of infection structures. MAPK signalling was also found to be involved in induction of plant systemic resistance in Trichoderma virens and in the hyperosmotic stress response in Trichoderma harzianum. Analyses of the function of components of the cAMP pathway during Trichoderma biocontrol revealed that mycoparasitism-associated coiling and chitinase production as well as secondary metabolism are affected by the internal cAMP level; in addition, a cross talk between regulation of light responses and the cAMP signalling pathway was found in Trichoderma atroviride.

  20. The bacterial lipopeptide iturins induce Verticillium dahliae cell death by affecting fungal signalling pathways and mediate plant defence responses involved in pathogen-associated molecular pattern-triggered immunity.

    Science.gov (United States)

    Han, Qin; Wu, Fengli; Wang, Xiaonan; Qi, Hong; Shi, Liang; Ren, Ang; Liu, Qinghai; Zhao, Mingwen; Tang, Canming

    2015-04-01

    Verticillium wilt in cotton caused by Verticillium dahliae is one of the most serious plant diseases worldwide. Because no known fungicides or cotton cultivars provide sufficient protection against this pathogen, V. dahliae causes major crop yield losses. Here, an isolated cotton endophytic bacterium, designated Bacillus amyloliquefaciens 41B-1, exhibited greater than 50% biocontrol efficacy against V. dahliae in cotton plants under greenhouse conditions. Through high-performance liquid chromatography and mass analysis of the filtrate, we found that the antifungal compounds present in the strain 41B-1 culture filtrate were a series of isoforms of iturins. The purified iturins suppressed V. dahliae microsclerotial germination in the absence or presence of cotton. Treatment with the iturins induced reactive oxygen species bursts, Hog1 mitogen-activated protein kinase (MAPK) activation and defects in cell wall integrity. The oxidative stress response and high-osmolarity glycerol pathway contribute to iturins resistance in V. dahliae. In contrast, the Slt2 MAPK pathway may be involved in iturins sensitivity in this fungus. In addition to antagonism, iturins could induce plant defence responses as activators and mediate pathogen-associated molecular pattern-triggered immunity. These findings suggest that iturins may affect fungal signalling pathways and mediate plant defence responses against V. dahliae. © 2014 Society for Applied Microbiology and John Wiley & Sons Ltd.

  1. The malarial host-targeting signal is conserved in the Irish potato famine pathogen.

    Directory of Open Access Journals (Sweden)

    2006-05-01

    consistent with the idea that the context of their presentation is constrained. These studies provide the first evidence to our knowledge that eukaryotic microbes share equivalent pathogenic HT signals and thus conserved mechanisms to access host cells across plant and animal kingdoms that may present unique targets for prophylaxis across divergent pathogens.

  2. The malarial host-targeting signal is conserved in the Irish potato famine pathogen.

    Science.gov (United States)

    Bhattacharjee, Souvik; Hiller, N Luisa; Liolios, Konstantinos; Win, Joe; Kanneganti, Thirumala-Devi; Young, Carolyn; Kamoun, Sophien; Haldar, Kasturi

    2006-05-01

    that the context of their presentation is constrained. These studies provide the first evidence to our knowledge that eukaryotic microbes share equivalent pathogenic HT signals and thus conserved mechanisms to access host cells across plant and animal kingdoms that may present unique targets for prophylaxis across divergent pathogens.

  3. NATO Defence Planning Process. Implications for defence posture

    Directory of Open Access Journals (Sweden)

    Paweł Fleischer

    2015-12-01

    Full Text Available The NATO Defence Planning Process (NDPP is the most important element affecting the Alliance's defence posture. Under the process states commit themselves to provide capabilities and forces required to fulfil NATO missions, defined in the NATO Strategic Concept. The NDPP directly affects national defence plans by harmonizing them with identified security and defence objectives as well by influencing development of the novel national defence capabilities. The emergence of new threats in the NATO environment, demands modifications in the defense planning process and establishing new goals for the Alliance. Enhancement of the NDPP should be priority during the time of unrest.

  4. From Defence To Development

    International Development Research Centre (IDRC) Digital Library (Canada)

    These figures are cold and lifeless indicators of human misery, hunger and homelessness. At the same time, South Africa has one of the most unequal distributions of income in the world. The current defence budget clearly absorbs resources which could be invested in infrastructure such as housing, clinics and schools.

  5. TNO and CBRN defence

    NARCIS (Netherlands)

    2015-01-01

    Within the Defence, Safety & Security branch of TNO a dedicated department focuses on Chemical, Biological, Radiological and Nuclear (CBRN) Protection. This is a world class research department consisting of about 50 people and a High Tox laboratory that is the only facility in The Netherlands that

  6. Lipoxin Signaling in Murine Lung Host Responses to Cryptococcus neoformans Infection.

    Science.gov (United States)

    Colby, Jennifer K; Gott, Katherine M; Wilder, Julie A; Levy, Bruce D

    2016-01-01

    Lipoxins (LX) are proresolving mediators that augment host defense against bacterial infection. Here, we investigated roles for LX in lung clearance of the fungal pathogen Cryptococcus neoformans (Cne). After intranasal inoculation of 5,000 CFU Cne, C57BL/6 and C.B-17 mice exhibited strain-dependent differences in Cne clearance, immunologic responses, and lipoxin A4 (LXA4) formation and receptor (ALX/FPR2) expression. Compared with C.B-17 mice, C57BL/6 lungs had increased and persistent Cne infection 14 days after inoculation, increased eosinophils, and distinct profiles of inflammatory cytokines. Relative to C.B-17 mice, bronchoalveolar lavage fluid levels of LXA4 were increased before and after infection in C57BL/6. The kinetics for 15-epi-LXA4 production were similar in both strains. Lung basal expression of the LX biosynthetic enzyme Alox12/15 (12/15-lipoxygenase) was increased in C57BL/6 mice and further increased after Cne infection. In contrast, lung basal expression of the LXA4 receptor Alx/Fpr2 was higher in C.B-17 relative to C57BL/6 mice, and after Cne infection, Alx/Fpr2 expression was significantly increased in only C.B-17 mice. Heat-killed Cne initiated lung cell generation of IFN-γ and IL-17 and was further increased in C.B-17 mice by 15-epi-LXA4. A trend toward reduced Cne clearance and IFN-γ production was observed upon in vivo administration of an ALX/FPR2 antagonist. Together, these findings provide the first evidence that alterations in cellular immunity against Cne are associated with differences in LXA4 production and receptor expression, suggesting an important role for ALX/FPR2 signaling in the regulation of pathogen-mediated inflammation and antifungal lung host defense.

  7. Efficient expression of nattokinase in Bacillus licheniformis: host strain construction and signal peptide optimization.

    Science.gov (United States)

    Wei, Xuetuan; Zhou, Yinhua; Chen, Jingbang; Cai, Dongbo; Wang, Dan; Qi, Gaofu; Chen, Shouwen

    2015-02-01

    Nattokinase (NK) possesses the potential for prevention and treatment of thrombus-related diseases. In this study, high-level expression of nattokinase was achieved in Bacillus licheniformis WX-02 via host strain construction and signal peptides optimization. First, ten genes (mpr, vpr, aprX, epr, bpr, wprA, aprE, bprA, hag, amyl) encoding for eight extracellular proteases, a flagellin and an amylase were deleted to obtain B. licheniformis BL10, which showed no extracellular proteases activity in gelatin zymography. Second, the gene fragments of P43 promoter, Svpr, nattokinase and TamyL were combined into pHY300PLK to form the expression vector pP43SNT. In BL10 (pP43SNT), the fermentation activity and product activity per unit of biomass of nattokinase reached 14.33 FU/mL and 2,187.71 FU/g respectively, which increased by 39 and 156 % compared to WX-02 (pP43SNT). Last, Svpr was replaced with SsacC and SbprA, and the maximum fermentation activity (33.83 FU/mL) was achieved using SsacC, which was 229 % higher than that of WX-02 (pP43SNT). The maximum NK fermentation activity in this study reaches the commercial production level of solid state fermentation, and this study provides a promising engineered strain for industrial production of nattokinase, as well as a potential platform host for expression of other target proteins.

  8. Missile defence : An overview

    OpenAIRE

    Weimar, P.W.L.

    2012-01-01

    At the present day, an unparalleled number of international actors, be it national governments or non-state groups, have acquired or are seeking to acquire both weapons of mass destruction and the means to deliver them. Those means of delivery can be Ballistic Missiles that can bridge vast – even intercontinental – distances. The use of Ballistic Missiles with conventional warheads is also an evolving threat as witnessed by the Chinese anti-ship ballistic missile. The defence of land forces a...

  9. Defence Industrial Strategy

    Science.gov (United States)

    2005-12-01

    B8.40 The Maritime Airborne Surveillance and Control ( MASC ) programme, aims to provide an assured airborne surveillance and control capability, forms...capability currently afforded by the Sea King Mk 7 Airborne Surveillance and Control variant. MASC should provide a capability for surveillance of the air...and surface as well as battle management of air defence fighters and other assets. The MASC programme is currently in the Assessment Phase. B8.41

  10. Adaptation to Environmental Stimuli within the Host: Two-Component Signal Transduction Systems of Mycobacterium tuberculosis

    Science.gov (United States)

    Bretl, Daniel J.; Demetriadou, Chrystalla; Zahrt, Thomas C.

    2011-01-01

    Summary: Pathogenic microorganisms encounter a variety of environmental stresses following infection of their respective hosts. Mycobacterium tuberculosis, the etiological agent of tuberculosis, is an unusual bacterial pathogen in that it is able to establish lifelong infections in individuals within granulomatous lesions that are formed following a productive immune response. Adaptation to this highly dynamic environment is thought to be mediated primarily through transcriptional reprogramming initiated in response to recognition of stimuli, including low-oxygen tension, nutrient depletion, reactive oxygen and nitrogen species, altered pH, toxic lipid moieties, cell wall/cell membrane-perturbing agents, and other environmental cues. To survive continued exposure to these potentially adverse factors, M. tuberculosis encodes a variety of regulatory factors, including 11 complete two-component signal transduction systems (TCSSs) and several orphaned response regulators (RRs) and sensor kinases (SKs). This report reviews our current knowledge of the TCSSs present in M. tuberculosis. In particular, we discuss the biochemical and functional characteristics of individual RRs and SKs, the environmental stimuli regulating their activation, the regulons controlled by the various TCSSs, and the known or postulated role(s) of individual TCSSs in the context of M. tuberculosis physiology and/or pathogenesis. PMID:22126994

  11. Altruistic defence behaviours in aphids

    Directory of Open Access Journals (Sweden)

    Brodeur Jacques

    2010-01-01

    Full Text Available Abstract Background Altruistic anti-predatory behaviours pose an evolutionary problem because they are costly to the actor and beneficial to the recipients. Altruistic behaviours can evolve through indirect fitness benefits when directed toward kin. The altruistic nature of anti-predatory behaviours is often difficult to establish because the actor can obtain direct fitness benefits, or the behaviour could result from selfish coercion by others, especially in eusocial animals. Non-eusocial parthenogenetically reproducing aphids form colonies of clone-mates, which are ideal to test the altruistic nature of anti-predatory defence behaviours. Many aphids release cornicle secretions when attacked by natural enemies such as parasitoids. These secretions contain an alarm pheromone that alerts neighbours (clone-mates of danger, thereby providing indirect fitness benefits to the actor. However, contact with cornicle secretions also hampers an attacker and could provide direct fitness to the actor. Results We tested the hypothesis that cornicle secretions are altruistic by assessing direct and indirect fitness consequences of smearing cornicle secretions onto an attacker, and by manipulating the number of clone-mates that could benefit from the behaviour. We observed parasitoids, Aphidius rhopalosiphi, foraging singly in patches of the cereal aphid Sitobion avenae of varied patch size (2, 6, and 12 aphids. Aphids that smeared parasitoids did not benefit from a reduced probability of parasitism, or increase the parasitoids' handling time. Smeared parasitoids, however, spent proportionately more time grooming and less time foraging, which resulted in a decreased host-encounter and oviposition rate within the host patch. In addition, individual smearing rate increased with the number of clone-mates in the colony. Conclusions Cornicle secretions of aphids were altruistic against parasitoids, as they provided no direct fitness benefits to secretion

  12. Altruistic defence behaviours in aphids.

    Science.gov (United States)

    Wu, Gi-Mick; Boivin, Guy; Brodeur, Jacques; Giraldeau, Luc-Alain; Outreman, Yannick

    2010-01-20

    Altruistic anti-predatory behaviours pose an evolutionary problem because they are costly to the actor and beneficial to the recipients. Altruistic behaviours can evolve through indirect fitness benefits when directed toward kin. The altruistic nature of anti-predatory behaviours is often difficult to establish because the actor can obtain direct fitness benefits, or the behaviour could result from selfish coercion by others, especially in eusocial animals. Non-eusocial parthenogenetically reproducing aphids form colonies of clone-mates, which are ideal to test the altruistic nature of anti-predatory defence behaviours. Many aphids release cornicle secretions when attacked by natural enemies such as parasitoids. These secretions contain an alarm pheromone that alerts neighbours (clone-mates) of danger, thereby providing indirect fitness benefits to the actor. However, contact with cornicle secretions also hampers an attacker and could provide direct fitness to the actor. We tested the hypothesis that cornicle secretions are altruistic by assessing direct and indirect fitness consequences of smearing cornicle secretions onto an attacker, and by manipulating the number of clone-mates that could benefit from the behaviour. We observed parasitoids, Aphidius rhopalosiphi, foraging singly in patches of the cereal aphid Sitobion avenae of varied patch size (2, 6, and 12 aphids). Aphids that smeared parasitoids did not benefit from a reduced probability of parasitism, or increase the parasitoids' handling time. Smeared parasitoids, however, spent proportionately more time grooming and less time foraging, which resulted in a decreased host-encounter and oviposition rate within the host patch. In addition, individual smearing rate increased with the number of clone-mates in the colony. Cornicle secretions of aphids were altruistic against parasitoids, as they provided no direct fitness benefits to secretion-releasing individuals, only indirect fitness benefits through

  13. Tetranychus evansi evades plant defence

    OpenAIRE

    Ataíde, Lívia Maria Silva

    2013-01-01

    Spider mites are known to induce or suppress plant defences. For instance, most strains of Tetranychus urticae induce plant defences regulated by jasmonic acid (JA) and salicylic acid (SA) pathways and this response has been correlated with a reduction in their reproductive performance on tomato plants. In contrast, the red spider mite Tetranychus evansi suppresses the JA and SA defences and both spider mite species were found to perform much better on tomato leaves that were previously attac...

  14. HIV Exploits Antiviral Host Innate GCN2-ATF4 Signaling for Establishing Viral Replication Early in Infection.

    Science.gov (United States)

    Jiang, Guochun; Santos Rocha, Clarissa; Hirao, Lauren A; Mendes, Erica A; Tang, Yuyang; Thompson, George R; Wong, Joseph K; Dandekar, Satya

    2017-05-02

    Antiviral innate host defenses against acute viral infections include suppression of host protein synthesis to restrict viral protein production. Less is known about mechanisms by which viral pathogens subvert host antiviral innate responses for establishing their replication and dissemination. We investigated early innate defense against human immunodeficiency virus (HIV) infection and viral evasion by utilizing human CD4 + T cell cultures in vitro and a simian immunodeficiency virus (SIV) model of AIDS in vivo Our data showed that early host innate defense against the viral infection involves GCN2-ATF4 signaling-mediated suppression of global protein synthesis, which is exploited by the virus for supporting its own replication during early viral infection and dissemination in the gut mucosa. Suppression of protein synthesis and induction of protein kinase GCN2-ATF4 signaling were detected in the gut during acute SIV infection. These changes diminished during chronic viral infection. HIV replication induced by serum deprivation in CD4 + T cells was linked to the induction of ATF4 that was recruited to the HIV long terminal repeat (LTR) to promote viral transcription. Experimental inhibition of GCN2-ATF4 signaling either by a specific inhibitor or by amino acid supplementation suppressed the induction of HIV expression. Enhancing ATF4 expression through selenium administration resulted in reactivation of latent HIV in vitro as well as ex vivo in the primary CD4 + T cells isolated from patients receiving suppressive antiretroviral therapy (ART). In summary, HIV/SIV exploits the early host antiviral response through GCN2-ATF4 signaling by utilizing ATF4 for activating the viral LTR transcription to establish initial viral replication and is a potential target for HIV prevention and therapy. IMPORTANCE Understanding how HIV overcomes host antiviral innate defense response in order to establish infection and dissemination is critical for developing prevention and

  15. Host condition and host immunity affect parasite fitness in a bird - ectoparasite system

    OpenAIRE

    Tschirren, Barbara; Bischoff, Linda; Saladin, Verena; Richner, Heinz

    2007-01-01

    1. Parasites might preferentially feed on hosts in good nutritional condition as such hosts provide better resources for the parasites’ own growth, survival and reproduction. However, hosts in prime condition are also better able to develop costly immunological or physiological defence mechanisms, which in turn reduce the parasites’ reproductive success. The interplay between host condition, host defence and parasite fitness will thus play an important part in the dynamics of host–parasite sy...

  16. Operational Analysis on Torpedo Defence

    NARCIS (Netherlands)

    Grootendorst, H.J.; Benders, F.P.A.; Fitski, H.J.; Veldhoven, E.R. van

    2007-01-01

    Since 1998, TNO Defence, Security and Safety has performed operational analysis with the Underwater Warfare Testbed, which provides an environment for evaluation and validation of systems, concepts, and tactics. On top of this testbed the Torpedo Defence System TestBed has been built to simulate

  17. The arbuscular mycorrhizal symbiosis promotes the systemic induction of regulatory defence-related genes in rice leaves and confers resistance to pathogen infection.

    Science.gov (United States)

    Campos-Soriano, Lidia; García-Martínez, José; San Segundo, Blanca

    2012-08-01

    Arbuscular mycorrhizal (AM) symbioses are mutualistic associations between soil fungi and most vascular plants. Their association benefits the host plant by improving nutrition, mainly phosphorus nutrition, and by providing increased capability to cope with adverse conditions. In this study, we investigated the transcriptional changes triggered in rice leaves as a result of AM symbiosis, focusing on the relevance of the plant defence response. We showed that root colonization by the AM fungus Glomus intraradices is accompanied by the systemic induction of genes that play a regulatory role in the host defence response, such as OsNPR1, OsAP2, OsEREBP and OsJAmyb. Genes involved in signal transduction processes (OsDUF26 and OsMPK6) and genes that function in calcium-mediated signalling processes (OsCBP, OsCaM and OsCML4) are also up-regulated in leaves of mycorrhizal rice plants in the absence of pathogen infection. In addition, the mycorrhizal rice plants exhibit a stronger induction of defence marker genes [i.e. pathogenesis-related (PR) genes] in their leaves in response to infection by the blast fungus Magnaporthe oryzae. Evidence indicates that mycorrhizal rice plants show enhanced resistance to the rice blast fungus. Overall, these results suggest that the protective effect of the AM symbiosis in rice plants relies on both the systemic activation of defence regulatory genes in the absence of pathogen challenge and the priming for stronger expression of defence effector genes during pathogen infection. The possible mechanisms involved in the mycorrhiza-induced resistance to M. oryzae infection are discussed. © 2011 The Authors. Molecular Plant Pathology © 2011 BSPP and Blackwell Publishing Ltd.

  18. A stilbene synthase allele from a Chinese wild grapevine confers resistance to powdery mildew by recruiting salicylic acid signalling for efficient defence.

    Science.gov (United States)

    Jiao, Yuntong; Xu, Weirong; Duan, Dong; Wang, Yuejin; Nick, Peter

    2016-10-01

    Stilbenes are central phytoalexins in Vitis, and induction of the key enzyme stilbene synthase (STS) is pivotal for disease resistance. Here, we address the potential for breeding resistance using an STS allele isolated from Chinese wild grapevine Vitis pseudoreticulata (VpSTS) by comparison with its homologue from Vitis vinifera cv. 'Carigane' (VvSTS). Although the coding regions of both alleles are very similar (>99% identity on the amino acid level), the promoter regions are significantly different. By expression in Arabidopsis as a heterologous system, we show that the allele from the wild Chinese grapevine can confer accumulation of stilbenes and resistance against the powdery mildew Golovinomyces cichoracearum, whereas the allele from the vinifera cultivar cannot. To dissect the upstream signalling driving the activation of this promoter, we used a dual-luciferase reporter system in a grapevine cell culture. We show elevated responsiveness of the promoter from the wild grape to salicylic acid (SA) and to the pathogen-associated molecular pattern (PAMP) flg22, equal induction of both alleles by jasmonic acid (JA), and a lack of response to the cell death-inducing elicitor Harpin. This elevated SA response of the VpSTS promoter depends on calcium influx, oxidative burst by RboH, mitogen-activated protein kinase (MAPK) signalling, and JA synthesis. We integrate the data in the context of a model where the resistance of V. pseudoreticulata is linked to a more efficient recruitment of SA signalling for phytoalexin synthesis. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  19. How Trypanosoma cruzi deals with oxidative stress: Antioxidant defence and DNA repair pathways.

    Science.gov (United States)

    Machado-Silva, Alice; Cerqueira, Paula Gonçalves; Grazielle-Silva, Viviane; Gadelha, Fernanda Ramos; Peloso, Eduardo de Figueiredo; Teixeira, Santuza Maria Ribeiro; Machado, Carlos Renato

    2016-01-01

    Trypanosoma cruzi, the causative agent of Chagas disease, is an obligatory intracellular parasite with a digenetic life cycle. Due to the variety of host environments, it faces several sources of oxidative stress. In addition to reactive oxygen species (ROS) produced by its own metabolism, T. cruzi must deal with high ROS levels generated as part of the host's immune responses. Hence, the conclusion that T. cruzi has limited ability to deal with ROS (based on the lack of a few enzymes involved with oxidative stress responses) seems somewhat paradoxical. Actually, to withstand such variable sources of oxidative stress, T. cruzi has developed complex defence mechanisms. This includes ROS detoxification pathways that are distinct from the ones in the mammalian host, DNA repair pathways and specialized polymerases, which not only protect its genome from the resulting oxidative damage but also contribute to the generation of genetic diversity within the parasite population. Recent studies on T. cruzi's DNA repair pathways as mismatch repair (MMR) and GO system suggested that, besides a role associated with DNA repair, some proteins of these pathways may also be involved in signalling oxidative damage. Recent data also suggested that an oxidative environment might be beneficial for parasite survival within the host cell as it contributes to iron mobilization from the host's intracellular storages. Besides contributing to the understanding of basic aspects of T. cruzi biology, these studies are highly relevant since oxidative stress pathways are part of the poorly understood mechanisms behind the mode of action of drugs currently used against this parasite. By unveiling new peculiar aspects of T. cruzi biology, emerging data on DNA repair pathways and other antioxidant defences from this parasite have revealed potential new targets for a much needed boost in drug development efforts towards a better treatment for Chagas disease. Copyright © 2015. Published by Elsevier B.V.

  20. Infection biology and defence responses in sorghum against Colletotrichum sublineolum

    DEFF Research Database (Denmark)

    Puttalingaiah, Basavaraju; Shetty, Nandini Prasad; Shetty, H. S.

    2009-01-01

    Aims: To investigate the infection biology of Colletotrichum sublineolum (isolate CP2126) and defence responses in leaves of resistant (SC146), intermediately resistant (SC326) and susceptible (BTx623) sorghum genotypes. Methods and Results: Infection biology and defence responses were studied......: The fact that there is a significant correlation between induced accumulation of H2O2, papilla formation and cell wall cross-linking, as evidenced by HRGP accumulation, and cessation of pathogen growth in resistant genotypes may help exploit host resistance in sorghum....

  1. Inhibition of predator attraction to kairomones by non-host plant volatiles for herbivores: a bypass-trophic signal.

    Directory of Open Access Journals (Sweden)

    Qing-He Zhang

    Full Text Available BACKGROUND: Insect predators and parasitoids exploit attractive chemical signals from lower trophic levels as kairomones to locate their herbivore prey and hosts. We hypothesized that specific chemical cues from prey non-hosts and non-habitats, which are not part of the trophic chain, are also recognized by predators and would inhibit attraction to the host/prey kairomone signals. To test our hypothesis, we studied the olfactory physiology and behavior of a predaceous beetle, Thanasimus formicarius (L. (Coleoptera: Cleridae, in relation to specific angiosperm plant volatiles, which are non-host volatiles (NHV for its conifer-feeding bark beetle prey. METHODOLOGY/PRINCIPAL FINDINGS: Olfactory detection in the clerid was confirmed by gas chromatography coupled to electroantennographic detection (GC-EAD for a subset of NHV components. Among NHV, we identified two strongly antennally active molecules, 3-octanol and 1-octen-3-ol. We tested the potential inhibition of the combination of these two NHV on the walking and flight responses of the clerid to known kairomonal attractants such as synthetic mixtures of bark beetle (Ips spp. aggregation pheromone components (cis-verbenol, ipsdienol, and E-myrcenol combined with conifer (Picea and Pinus spp. monoterpenes (alpha-pinene, terpinolene, and Delta(3-carene. There was a strong inhibitory effect, both in the laboratory (effect size d = -3.2, walking bioassay and in the field (d = -1.0, flight trapping. This is the first report of combining antennal detection (GC-EAD and behavioral responses to identify semiochemical molecules that bypass the trophic system, signaling habitat information rather than food related information. CONCLUSIONS/SIGNIFICANCE: Our results, along with recent reports on hymenopteran parasitoids and coleopteran predators, suggest that some NHV chemicals for herbivores are part of specific behavioral signals for the higher trophic level and not part of a background noise. Such bypass

  2. How insects overcome two-component plant chemical defence

    DEFF Research Database (Denmark)

    Pentzold, Stefan; Zagrobelny, Mika; Rook, Frederik

    2014-01-01

    , before and during feeding as well as during digestion, and at several levels such as the insects’ feeding behaviour, physiology and metabolism. Insect adaptations frequently circumvent or counteract the activity of the plant β-glucosidases, bioactivating enzymes that are a key element in the plant’s two......-component chemical defence. These adaptations include host plant choice, non-disruptive feeding guilds and various physiological adaptations as well as metabolic enzymatic strategies of the insect’s digestive system. Furthermore, insect adaptations often act in combination, may exist in both generalists......Insect herbivory is often restricted by glucosylated plant chemical defence compounds that are activated by plant β-glucosidases to release toxic aglucones upon plant tissue damage. Such two-component plant defences are widespread in the plant kingdom and examples of these classes of compounds...

  3. Toxoplasma gondii induces FAK-Src-STAT3 signaling during infection of host cells that prevents parasite targeting by autophagy.

    Directory of Open Access Journals (Sweden)

    Jose-Andres C Portillo

    2017-10-01

    Full Text Available Targeting of Toxoplasma gondii by autophagy is an effective mechanism by which host cells kill the protozoan. Thus, the parasite must avoid autophagic targeting to survive. Here we show that the mammalian cytoplasmic molecule Focal Adhesion Kinase (FAK becomes activated during invasion of host cells. Activated FAK appears to accompany the formation of the moving junction (as assessed by expression the parasite protein RON4. FAK activation was inhibited by approaches that impaired β1 and β3 integrin signaling. FAK caused activation of Src that in turn mediated Epidermal Growth Factor Receptor (EGFR phosphorylation at the unique Y845 residue. Expression of Src-resistant Y845F EGFR mutant markedly inhibited ROP16-independent activation of STAT3 in host cells. Activation of FAK, Y845 EGFR or STAT3 prevented activation of PKR and eIF2α, key stimulators of autophagy. Genetic or pharmacologic inhibition of FAK, Src, EGFR phosphorylation at Y845, or STAT3 caused accumulation of the autophagy protein LC3 and LAMP-1 around the parasite and parasite killing dependent on autophagy proteins (ULK1 and Beclin 1 and lysosomal enzymes. Parasite killing was inhibited by expression of dominant negative PKR. Thus, T. gondii activates a FAK→Src→Y845-EGFR→STAT3 signaling axis within mammalian cells, thereby enabling the parasite to survive by avoiding autophagic targeting through a mechanism likely dependent on preventing activation of PKR and eIF2α.

  4. Independent Effects of a Herbivore’s Bacterial Symbionts on Its Performance and Induced Plant Defences

    Science.gov (United States)

    Staudacher, Heike; Schimmel, Bernardus C. J.; Lamers, Mart M.; Wybouw, Nicky; Groot, Astrid T.; Kant, Merijn R.

    2017-01-01

    It is well known that microbial pathogens and herbivores elicit defence responses in plants. Moreover, microorganisms associated with herbivores, such as bacteria or viruses, can modulate the plant’s response to herbivores. Herbivorous spider mites can harbour different species of bacterial symbionts and exert a broad range of effects on host-plant defences. Hence, we tested the extent to which such symbionts affect the plant’s defences induced by their mite host and assessed if this translates into changes in plant resistance. We assessed the bacterial communities of two strains of the common mite pest Tetranychus urticae. We found that these strains harboured distinct symbiotic bacteria and removed these using antibiotics. Subsequently, we tested to which extent mites with and without symbiotic bacteria induce plant defences in terms of phytohormone accumulation and defence gene expression, and assessed mite oviposition and survival as a measure for plant resistance. We observed that the absence/presence of these bacteria altered distinct plant defence parameters and affected mite performance but we did not find indications for a causal link between the two. We argue that although bacteria-related effects on host-induced plant defences may occur, these do not necessarily affect plant resistance concomitantly. PMID:28106771

  5. Independent Effects of a Herbivore's Bacterial Symbionts on Its Performance and Induced Plant Defences.

    Science.gov (United States)

    Staudacher, Heike; Schimmel, Bernardus C J; Lamers, Mart M; Wybouw, Nicky; Groot, Astrid T; Kant, Merijn R

    2017-01-18

    It is well known that microbial pathogens and herbivores elicit defence responses in plants. Moreover, microorganisms associated with herbivores, such as bacteria or viruses, can modulate the plant's response to herbivores. Herbivorous spider mites can harbour different species of bacterial symbionts and exert a broad range of effects on host-plant defences. Hence, we tested the extent to which such symbionts affect the plant's defences induced by their mite host and assessed if this translates into changes in plant resistance. We assessed the bacterial communities of two strains of the common mite pest Tetranychus urticae. We found that these strains harboured distinct symbiotic bacteria and removed these using antibiotics. Subsequently, we tested to which extent mites with and without symbiotic bacteria induce plant defences in terms of phytohormone accumulation and defence gene expression, and assessed mite oviposition and survival as a measure for plant resistance. We observed that the absence/presence of these bacteria altered distinct plant defence parameters and affected mite performance but we did not find indications for a causal link between the two. We argue that although bacteria-related effects on host-induced plant defences may occur, these do not necessarily affect plant resistance concomitantly.

  6. Independent Effects of a Herbivore’s Bacterial Symbionts on Its Performance and Induced Plant Defences

    Directory of Open Access Journals (Sweden)

    Heike Staudacher

    2017-01-01

    Full Text Available It is well known that microbial pathogens and herbivores elicit defence responses in plants. Moreover, microorganisms associated with herbivores, such as bacteria or viruses, can modulate the plant’s response to herbivores. Herbivorous spider mites can harbour different species of bacterial symbionts and exert a broad range of effects on host-plant defences. Hence, we tested the extent to which such symbionts affect the plant’s defences induced by their mite host and assessed if this translates into changes in plant resistance. We assessed the bacterial communities of two strains of the common mite pest Tetranychus urticae. We found that these strains harboured distinct symbiotic bacteria and removed these using antibiotics. Subsequently, we tested to which extent mites with and without symbiotic bacteria induce plant defences in terms of phytohormone accumulation and defence gene expression, and assessed mite oviposition and survival as a measure for plant resistance. We observed that the absence/presence of these bacteria altered distinct plant defence parameters and affected mite performance but we did not find indications for a causal link between the two. We argue that although bacteria-related effects on host-induced plant defences may occur, these do not necessarily affect plant resistance concomitantly.

  7. Inhibition of host extracellular signal-regulated kinase (ERK) activation decreases new world alphavirus multiplication in infected cells

    Energy Technology Data Exchange (ETDEWEB)

    Voss, Kelsey; Amaya, Moushimi [National Center for Biodefense and Infectious Diseases, School of Systems Biology, George Mason University, 10650 Pyramid Place, Manassas, VA (United States); Mueller, Claudius [Center for Applied Proteomics and Personalized Medicine, George Mason University, 10900 University Boulevard, Manassas, VA (United States); Roberts, Brian [Leidos Health Life Sciences, 5202 Presidents Court, Suite 110, Frederick, MD (United States); Kehn-Hall, Kylene; Bailey, Charles [National Center for Biodefense and Infectious Diseases, School of Systems Biology, George Mason University, 10650 Pyramid Place, Manassas, VA (United States); Petricoin, Emanuel [Center for Applied Proteomics and Personalized Medicine, George Mason University, 10900 University Boulevard, Manassas, VA (United States); Narayanan, Aarthi, E-mail: anaraya1@gmu.edu [National Center for Biodefense and Infectious Diseases, School of Systems Biology, George Mason University, 10650 Pyramid Place, Manassas, VA (United States)

    2014-11-15

    New World alphaviruses belonging to the family Togaviridae are classified as emerging infectious agents and Category B select agents. Our study is focused on the role of the host extracellular signal-regulated kinase (ERK) in the infectious process of New World alphaviruses. Infection of human cells by Venezuelan equine encephalitis virus (VEEV) results in the activation of the ERK-signaling cascade. Inhibition of ERK1/2 by the small molecule inhibitor Ag-126 results in inhibition of viral multiplication. Ag-126-mediated inhibition of VEEV was due to potential effects on early and late stages of the infectious process. While expression of viral proteins was down-regulated in Ag-126 treated cells, we did not observe any influence of Ag-126 on the nuclear distribution of capsid. Finally, Ag-126 exerted a broad-spectrum inhibitory effect on New World alphavirus multiplication, thus indicating that the host kinase, ERK, is a broad-spectrum candidate for development of novel therapeutics against New World alphaviruses. - Highlights: • VEEV infection activated multiple components of the ERK signaling cascade. • Inhibition of ERK activation using Ag-126 inhibited VEEV multiplication. • Activation of ERK by Ceramide C6 increased infectious titers of TC-83. • Ag-126 inhibited virulent strains of all New World alphaviruses. • Ag-126 treatment increased percent survival of infected cells.

  8. cAMP signalling regulates synchronised growth of symbiotic Epichloë fungi with the host grass Lolium perenne

    Directory of Open Access Journals (Sweden)

    Christine Rosalie Voisey

    2016-10-01

    Full Text Available The seed-transmitted fungal symbiont, Epichloë festucae, colonizes grasses by infecting host tissues as they form on the shoot apical meristem (SAM of the seedling. How this fungus accommodates the complexities of plant development to successfully colonize the leaves and inflorescences is unclear. Since adenosine 3′, 5′-cyclic monophosphate (cAMP-dependent signaling is often essential for host colonization by fungal pathogens, we disrupted the cAMP cascade by insertional mutagenesis of the E. festucae adenylate cyclase gene (acyA. Consistent with deletions of this gene in other fungi, acyA mutants had a slow radial growth rate in culture, and hyphae were convoluted and hyper-branched suggesting that fungal apical dominance had been disrupted. Nitro blue tetrazolium (NBT staining of hyphae showed that cAMP disruption mutants were impaired in their ability to synthesize superoxide, indicating that cAMP signaling regulates accumulation of reactive oxygen species (ROS. Despite significant defects in hyphal growth and ROS production, E. festucae ΔacyA mutants were infectious and capable of forming symbiotic associations with grasses. Plants infected with E. festucae ΔacyA were marginally less robust than the wild-type (WT, however hyphae were hyper-branched, and leaf tissues heavily colonized, indicating that the tight regulation of hyphal growth normally observed in maturing leaves requires functional cAMP signaling.

  9. Probabilistic Flood Defence Assessment Tools

    Directory of Open Access Journals (Sweden)

    Slomp Robert

    2016-01-01

    Full Text Available The WTI2017 project is responsible for the development of flood defence assessment tools for the 3600 km of Dutch primary flood defences, dikes/levees, dunes and hydraulic structures. These tools are necessary, as per January 1st 2017, the new flood risk management policy for the Netherlands will be implemented. Then, the seven decades old design practice (maximum water level methodology of 1958 and two decades old safety standards (and maximum hydraulic load methodology of 1996 will formally be replaced by a more risked based approach for the national policy in flood risk management. The formal flood defence assessment is an important part of this new policy, especially for flood defence managers, since national and regional funding for reinforcement is based on this assessment. This new flood defence policy is based on a maximum allowable probability of flooding. For this, a maximum acceptable individual risk was determined at 1/100 000 per year, this is the probability of life loss of for every protected area in the Netherlands. Safety standards of flood defences were then determined based on this acceptable individual risk. The results were adjusted based on information from cost -benefit analysis, societal risk and large scale societal disruption due to the failure of critical infrastructure e.g. power stations. The resulting riskbased flood defence safety standards range from a 300 to a 100 000 year return period for failure. Two policy studies, WV21 (Safety from floods in the 21st century and VNK-2 (the National Flood Risk in 2010 provided the essential information to determine the new risk based safety standards for flood defences. The WTI2017 project will provide the safety assessment tools based on these new standards and is thus an essential element for the implementation of this policy change. A major issue to be tackled was the development of user-friendly tools, as the new assessment is to be carried out by personnel of the

  10. In Defence of Pashukanism

    Directory of Open Access Journals (Sweden)

    R Koen

    2011-07-01

    Full Text Available This essay presents an extended defence of the general theory of law formulated by the Bolshevik jurist, Evgeny Pashukanis, and published in his Law and Marxism: A General Theory in 1924. The general theory is a theory of the legal form. Although Pashukanis did not name his theory, it has become known as the commodity form theory of law because of its theorising the legal form as a homologue of the commodity form. However, despite having weighty Marxist and revolutionary Bolshevik credentials, the general theory has been subjected to sustained attack, especially from new left and neo-Marxist circles. This essay identifies and explicates six major objections to Pashukanism from its left critics. These are that the general theory is too abstract to comprehend the reality of legal relations; that it is infused with economic reductionism; that it derives the legal form wrongly from commodity exchange; that it classifies the legal form incorrectly as an attribute of capitalism only; that it lacks the generality required of a general theory of law; and that it is imbricated in the growth of anarchism and Stalinism. Following a brief exegetical exercise, the bulk of the essay is devoted to demonstrating in detail that each of the six objections to the general theory is without merit, and that none makes any serious incursion into its integrity as a theory of the legal form. The central submission of the essay is that the Pashukanist general theory of law is rooted in the first principles of classical Marxism and hence may lay claim legitimately to being the Marxist theory of law.

  11. Trained immunity: A smart way to enhance innate immune defence.

    Science.gov (United States)

    van der Meer, Jos W M; Joosten, Leo A B; Riksen, Niels; Netea, Mihai G

    2015-11-01

    The innate arm of the immune system is generally viewed as primitive and non-specific and - in contrast to the adaptive immune arm - not to possess memory. However in plants and invertebrate animals that lack adaptive immunity, innate immunity will exhibit a prolonged enhanced functional state after adequate priming. A similar enhancement of function of the innate immunity has occasionally been described in vertebrates, including humans. Over the past few years we have studied this phenomenon in greater detail and we have coined the term 'Trained (innate) immunity' (TI). TI can be induced by a variety of stimuli, of which we have studied BCG and β-glucan in greater detail. The non-specific protective effects of BCG that have been observed in vaccination studies in the literature are probably due to TI. Monocytes and macrophages are among the main cells of the innate immune arm that can be trained. We have discovered that both BCG (via NOD2 signalling) and β-glucan (via dectin-1) induce epigenetic reprogramming, in particular stable changes in histone trimethylation at H3K4. These epigenetic changes lead to cellular activation, enhanced cytokine production and a change in the metabolic state of the cell with a shift from oxidative phosphorylation to aerobic glycolysis. TI is not only important for host defence and vaccine responses, but most probably also for diseases like atherosclerosis. Modulation of TI is a promising area for new treatments. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. Involvement of the mitogen-activated protein (MAP kinase signalling pathway in host cell invasion by Toxoplasma gondii

    Directory of Open Access Journals (Sweden)

    Robert-Gangneux F.

    2000-06-01

    Full Text Available Little is known about signalling in Toxoplasma gondii, but it is likely that protein kinases might play a key role in the parasite proliferation, differentiation and probably invasion. We previously characterized Mitogen-Activated Protein (MAP kinases in T. gondii lysates. In this study, cultured cells were tested for their susceptibility to Toxoplasma gondii infection after tachyzoite pretreatment with drugs interfering with AMP kinase activation pathways. Protein kinases inhibitors, i.e. genistein, R031-8220 and PD098059, reduced tachyzoite infectivity by 38 ± 4.5 %, 85.5 ± 9 % and 56 ± 10 %, respectively. Conversely, protein kinases activators, i.e. bombesin and PMA, markedly increased infectivity (by 202 ± 37 % and 258 ± 14 %, respectively. These results suggest that signalling pathways involving PKC and AAAP kinases play a role in host cell invasion by Toxoplasma.

  13. NOD2 signaling contributes to host defense in the lungs against Escherichia coli infection.

    Science.gov (United States)

    Theivanthiran, Balamayooran; Batra, Sanjay; Balamayooran, Gayathriy; Cai, Shanshan; Kobayashi, Koichi; Flavell, Richard A; Jeyaseelan, Samithamby

    2012-07-01

    Bacterial pneumonia remains a significant cause of mortality in the United States. The innate immune response is the first line of defense against invading bacteria. Neutrophil recruitment to the lungs is the first step in a multistep sequence leading to bacterial clearance. Ligand interaction with pattern-recognizing receptors (PRRs) leads to chemokine production, which drives neutrophils to the site of infection. Although we demonstrated that RIP2 is important for host defense in the lungs against Escherichia coli, the individual roles of NOD1 and NOD2 in pulmonary defense have not been addressed. Here, we explored the role of NOD2 in neutrophil-mediated host defense against an extracellular pathogen, E. coli. We found enhanced bacterial burden and reduced neutrophil and cytokine/chemokine levels in the lungs of NOD2⁻/⁻ mice following E. coli infection. Furthermore, we observed reduced activation of NF-κB and mitogen-activated protein kinases (MAPKs) in the lungs of NOD2⁻/⁻ mice upon E. coli challenge. Moreover, NOD2⁻/⁻ neutrophils show impaired intracellular bacterial killing. Using NOD2/RIP2⁻/⁻ mice, we observed bacterial burden and neutrophil accumulation in the lungs similar to those seen with NOD2⁻/⁻ mice. In addition, bone marrow-derived macrophages obtained from NOD2/RIP2⁻/⁻ mice demonstrate a reduction in activation of NF-κB and MAPKs similar to that seen with NOD2⁻/⁻ mice in response to E. coli. These findings unveil a previously unrecognized role of the NOD2-RIP2 axis for host defense against extracellular Gram-negative bacteria. This pathway may represent a novel target for the treatment of lung infection/inflammation.

  14. ATP1A1-mediated Src signaling inhibits coronavirus entry into host cells

    NARCIS (Netherlands)

    C. Burkard (Christine); M.H. Verheije (Monique); B.L. Haagmans (Bart); F.J.M. van Kuppeveld (Frank ); P.J.M. Rottier (Peter); B.J. Bosch (Berend Jan); C.A.M. de Haan (Cornelis)

    2015-01-01

    textabstractIn addition to transporting ions, the multisubunit Na+,K+-ATPase also functions by relaying cardiotonic steroid (CTS)-binding- induced signals into cells. In this study, we analyzed the role of Na+,K+-ATPase and, in particular, of its ATP1A1 α subunit during coronavirus (CoV) infection.

  15. ATP1A1-mediated Src signaling inhibits coronavirus entry into host cells

    NARCIS (Netherlands)

    Burkard, Christine; Verheije, Monique H; Haagmans, Bart L; van Kuppeveld, Frank J; Rottier, Peter J M; Bosch, Berend-Jan; de Haan, Cornelis A M

    2015-01-01

    Besides by transporting ions the multi-subunit Na(+),K(+)-ATPase also functions by relaying cardiotonic steroid-binding induced signals into cells. In this study we analyzed the role of Na(+),K(+)-ATPase and in particular of its ATP1A1 α-subunit during coronavirus (CoV) infection. As controls, the

  16. Characterization of Arabidopsis Transcriptional Responses to Different Aphid Species Reveals Genes that Contribute to Host Susceptibility and Non-host Resistance

    Science.gov (United States)

    Jaouannet, Maëlle; Morris, Jenny A.; Hedley, Peter E.; Bos, Jorunn I. B.

    2015-01-01

    Aphids are economically important pests that display exceptional variation in host range. The determinants of diverse aphid host ranges are not well understood, but it is likely that molecular interactions are involved. With significant progress being made towards understanding host responses upon aphid attack, the mechanisms underlying non-host resistance remain to be elucidated. Here, we investigated and compared Arabidopsis thaliana host and non-host responses to aphids at the transcriptional level using three different aphid species, Myzus persicae, Myzus cerasi and Rhopalosiphum pisum. Gene expression analyses revealed a high level of overlap in the overall gene expression changes during the host and non-host interactions with regards to the sets of genes differentially expressed and the direction of expression changes. Despite this overlap in transcriptional responses across interactions, there was a stronger repression of genes involved in metabolism and oxidative responses specifically during the host interaction with M. persicae. In addition, we identified a set of genes with opposite gene expression patterns during the host versus non-host interactions. Aphid performance assays on Arabidopsis mutants that were selected based on our transcriptome analyses identified novel genes contributing to host susceptibility, host defences during interactions with M. persicae as well to non-host resistance against R. padi. Understanding how plants respond to aphid species that differ in their ability to infest plant species, and identifying the genes and signaling pathways involved, is essential for the development of novel and durable aphid control in crop plants. PMID:25993686

  17. Characterization of Arabidopsis Transcriptional Responses to Different Aphid Species Reveals Genes that Contribute to Host Susceptibility and Non-host Resistance.

    Directory of Open Access Journals (Sweden)

    Maëlle Jaouannet

    2015-05-01

    Full Text Available Aphids are economically important pests that display exceptional variation in host range. The determinants of diverse aphid host ranges are not well understood, but it is likely that molecular interactions are involved. With significant progress being made towards understanding host responses upon aphid attack, the mechanisms underlying non-host resistance remain to be elucidated. Here, we investigated and compared Arabidopsis thaliana host and non-host responses to aphids at the transcriptional level using three different aphid species, Myzus persicae, Myzus cerasi and Rhopalosiphum pisum. Gene expression analyses revealed a high level of overlap in the overall gene expression changes during the host and non-host interactions with regards to the sets of genes differentially expressed and the direction of expression changes. Despite this overlap in transcriptional responses across interactions, there was a stronger repression of genes involved in metabolism and oxidative responses specifically during the host interaction with M. persicae. In addition, we identified a set of genes with opposite gene expression patterns during the host versus non-host interactions. Aphid performance assays on Arabidopsis mutants that were selected based on our transcriptome analyses identified novel genes contributing to host susceptibility, host defences during interactions with M. persicae as well to non-host resistance against R. padi. Understanding how plants respond to aphid species that differ in their ability to infest plant species, and identifying the genes and signaling pathways involved, is essential for the development of novel and durable aphid control in crop plants.

  18. Terpenoids in plant and arbuscular mycorrhiza-reinforced defence against herbivorous insects.

    Science.gov (United States)

    Sharma, Esha; Anand, Garima; Kapoor, Rupam

    2017-03-01

    Plants, though sessile, employ various strategies to defend themselves against herbivorous insects and convey signals of an impending herbivore attack to other plant(s). Strategies include the production of volatiles that include terpenoids and the formation of symbiotic associations with fungi, such as arbuscular mycorrhiza (AM). This constitutes a two-pronged above-ground/below-ground attack-defence strategy against insect herbivores. Terpenoids represent an important constituent of herbivore-induced plant volatiles that deter herbivores and/or attract their predators. Terpenoids serve as airborne signals that can induce defence responses in systemic undamaged parts of the plant and also prime defence responses in neighbouring plants. Colonization of roots by AM fungi is known to influence secondary metabolism in plants; this includes alteration of the concentration and composition of terpenoids, which can boost both direct and indirect plant defence against herbivorous insects. Enhanced nutrient uptake facilitated by AM, changes in plant morphology and physiology and increased transcription levels of certain genes involved in the terpenoid biosynthesis pathway result in alterations in plant terpenoid profiles. The common mycorrhizal networks of external hyphae have added a dimension to the two-pronged plant defence strategy. These act as conduits to transfer defence signals and terpenoids. Improved understanding of the roles of terpenoids in plant and AM defences against herbivory and of interplant signalling in natural communities has significant implications for sustainable management of pests in agricultural ecosystems.

  19. High-mass X-ray binaries and the cosmic 21-cm signal: impact of host galaxy absorption

    Science.gov (United States)

    Das, Arpan; Mesinger, Andrei; Pallottini, Andrea; Ferrara, Andrea; Wise, John H.

    2017-07-01

    By heating the intergalactic medium (IGM) before reionization, X-rays are expected to play a prominent role in the early Universe. The cosmic 21-cm signal from this 'epoch of heating' (EoH) could serve as a clean probe of high-energy processes inside the first galaxies. Here, we improve on prior estimates of this signal by using high-resolution hydrodynamic simulations to calculate the X-ray absorption due to the interstellar medium (ISM) of the host galaxy, typically residing in haloes with mass 107.5-8.5 M⊙ at z ˜ 8-15. X-rays absorbed inside the host galaxy are unable to escape into the IGM and contribute to the EoH. We find that the X-ray opacity through these galaxies can be approximated by a metal-free ISM with a typical column density of log [N_{H I}/cm^{-2}] = 21.4^{+0.40}_{-0.65}. We compute the resulting 21-cm signal by combining these ISM opacities with public spectra of high-mass X-ray binaries (thought to be important X-ray sources in the early Universe). Our results support 'standard scenarios' in which the X-ray heating of the IGM is inhomogeneous, and occurs before the bulk of reionization. The large-scale (k ˜ 0.1 Mpc-1) 21-cm power reaches a peak of ≈100 mK2 at z ˜ 10-15, with the redshift depending on the cosmic star formation history. Our main results can be reproduced by approximating the X-ray emission from high-mass X-ray binaries by a power law with energy index α ≈ 1, truncated at energies below 0.5 keV.

  20. Delineating the effect of host environmental signals on a fully virulent strain of Bacillus anthracis using an integrated transcriptomics and proteomics approach

    NARCIS (Netherlands)

    Panda, G.; Basak, T.; Tanwer, P.; Sengupta, S.; Martins dos Santos, V.A.P.; Bhatnagar, R.

    2014-01-01

    Pathogenic bacteria sense the host environment and regulate expression of virulence-related genes. Environmental signals like temperature, bicarbonate/CO2 and glucose induce toxin production in Bacillus anthracis, but the mechanisms by which these signals contribute to virulence and overall

  1. Do cytokinins function as two-way signals between plants and animals? Cytokinins may not only mediate defence reactions via secondary compounds, but may directly interfere with developmental signals in insects.

    Science.gov (United States)

    Robischon, Marcel

    2015-04-01

    Cytokinins are plant hormones that have, among many other functions, senescence-modulatory effects in plant tissue. This is evident not only from biochemical data, but is vividly illustrated in the "green island" phenotype in plant leaves caused by cytokinins released for example by leaf mining insects or microbial pathogens. It is beyond doubt that, in addition to their roles in plants, cytokinins also provoke physiological and developmental effects in animals. It is hypothesized that the recently much discussed modification of plant metabolism by insects and associated microbes via cytokinin signals has a counterpart in direct cytokinin signalling that interferes with the animals' hormonal systems and impacts their population dynamics. © 2015 WILEY Periodicals, Inc.

  2. Pathogenic bacteria target NEDD8-conjugated cullins to hijack host-cell signaling pathways.

    Directory of Open Access Journals (Sweden)

    Grégory Jubelin

    2010-09-01

    Full Text Available The cycle inhibiting factors (Cif, produced by pathogenic bacteria isolated from vertebrates and invertebrates, belong to a family of molecules called cyclomodulins that interfere with the eukaryotic cell cycle. Cif blocks the cell cycle at both the G₁/S and G₂/M transitions by inducing the stabilization of cyclin-dependent kinase inhibitors p21(waf1 and p27(kip1. Using yeast two-hybrid screens, we identified the ubiquitin-like protein NEDD8 as a target of Cif. Cif co-compartmentalized with NEDD8 in the host cell nucleus and induced accumulation of NEDD8-conjugated cullins. This accumulation occurred early after cell infection and correlated with that of p21 and p27. Co-immunoprecipitation revealed that Cif interacted with cullin-RING ubiquitin ligase complexes (CRLs through binding with the neddylated forms of cullins 1, 2, 3, 4A and 4B subunits of CRL. Using an in vitro ubiquitylation assay, we demonstrate that Cif directly inhibits the neddylated CUL1-associated ubiquitin ligase activity. Consistent with this inhibition and the interaction of Cif with several neddylated cullins, we further observed that Cif modulates the cellular half-lives of various CRL targets, which might contribute to the pathogenic potential of diverse bacteria.

  3. Pathogenic bacteria target NEDD8-conjugated cullins to hijack host-cell signaling pathways.

    Science.gov (United States)

    Jubelin, Grégory; Taieb, Frédéric; Duda, David M; Hsu, Yun; Samba-Louaka, Ascel; Nobe, Rika; Penary, Marie; Watrin, Claude; Nougayrède, Jean-Philippe; Schulman, Brenda A; Stebbins, C Erec; Oswald, Eric

    2010-09-30

    The cycle inhibiting factors (Cif), produced by pathogenic bacteria isolated from vertebrates and invertebrates, belong to a family of molecules called cyclomodulins that interfere with the eukaryotic cell cycle. Cif blocks the cell cycle at both the G₁/S and G₂/M transitions by inducing the stabilization of cyclin-dependent kinase inhibitors p21(waf1) and p27(kip1). Using yeast two-hybrid screens, we identified the ubiquitin-like protein NEDD8 as a target of Cif. Cif co-compartmentalized with NEDD8 in the host cell nucleus and induced accumulation of NEDD8-conjugated cullins. This accumulation occurred early after cell infection and correlated with that of p21 and p27. Co-immunoprecipitation revealed that Cif interacted with cullin-RING ubiquitin ligase complexes (CRLs) through binding with the neddylated forms of cullins 1, 2, 3, 4A and 4B subunits of CRL. Using an in vitro ubiquitylation assay, we demonstrate that Cif directly inhibits the neddylated CUL1-associated ubiquitin ligase activity. Consistent with this inhibition and the interaction of Cif with several neddylated cullins, we further observed that Cif modulates the cellular half-lives of various CRL targets, which might contribute to the pathogenic potential of diverse bacteria.

  4. Host-pathogen systems biology: logical modelling of hepatocyte growth factor and Helicobacter pylori induced c-Met signal transduction

    Directory of Open Access Journals (Sweden)

    Kähne Thilo

    2008-01-01

    pharmacological inhibitor against PLCγ1. The in silico predictions for the knockout of two other network components were also verified experimentally. Conclusion This work represents one of the first approaches in the direction of host-pathogen systems biology aiming at deciphering signalling changes brought about by pathogenic bacteria. The suitability of our network model is demonstrated by an in silico prediction of a relevant target against pathogen infection.

  5. Operational Analysis on Torpedo Defence

    NARCIS (Netherlands)

    Grootendordt, H.J.; Benders, F.P.A.; Fitski, H.J.; Veldhoven, E.R. van

    2008-01-01

    Surface vessels and submarines must be able to defend themselves against a torpedo attack. Self-defence can be approached as a modular concept. The first module involves 'Detection, Classification and Localisation (DCL)'. DCL triggers the second module: the 'evaluator'. This module starts the last

  6. In defence of Modern Languages

    Directory of Open Access Journals (Sweden)

    Gerda Wielander

    2014-10-01

    Full Text Available This article is a 3000 word long opinion piece/commentary in defence of Modern Languages as an academic discipline in its own right. it outlines some of the reasons why Modern Languages find themselves in a difficult position and argues that the future lies in cooperation, innovation and confident showcasing of Modern Languages research as exmplified by MLO.

  7. Pancreatic amylase is an environmental signal for regulation of biofilm formation and host interaction in Campylobacter jejuni.

    Science.gov (United States)

    Jowiya, Waheed; Brunner, Katja; Abouelhadid, Sherif; Hussain, Haitham A; Nair, Sean P; Sadiq, Sohaib; Williams, Lisa K; Trantham, Emma K; Stephenson, Holly; Wren, Brendan W; Bajaj-Elliott, Mona; Cogan, Tristan A; Laws, Andrew P; Wade, Jim; Dorrell, Nick; Allan, Elaine

    2015-12-01

    Campylobacter jejuni is a commensal bacterium in the intestines of animals and birds and a major cause of food-borne gastroenteritis in humans worldwide. Here we show that exposure to pancreatic amylase leads to secretion of an α-dextran by C. jejuni and that a secreted protease, Cj0511, is required. Exposure of C. jejuni to pancreatic amylase promotes biofilm formation in vitro, increases interaction with human epithelial cell lines, increases virulence in the Galleria mellonella infection model, and promotes colonization of the chicken ileum. We also show that exposure to pancreatic amylase protects C. jejuni from stress conditions in vitro, suggesting that the induced α-dextran may be important during transmission between hosts. This is the first evidence that pancreatic amylase functions as an interkingdom signal in an enteric microorganism. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  8. Differences in two-component signal transduction proteins among the genus Brucella: implications for host preference and pathogenesis

    DEFF Research Database (Denmark)

    Binnewies, Tim Terence; Ussery, David; Lavín, JL

    2010-01-01

    Two-component systems (TCSs) are the predominant bacterial signal transduction mechanisms. Species of the genus Brucella are genetically highly related and differ mainly in mammalian host adaptation and pathogenesis. In this study, TCS proteins encoded in the available genome sequences of Brucella...... species have been identified using bioinformatic methods. All the Brucella species share an identical set of TCS proteins, and the number of TCS proteins in the closely related opportunistic human pathogen Ochrobactrum anthropi was higher than in Brucella species as expected from its lifestyle. O....... anthropi lacks orthologs of the Brucella TCSs NodVW, TceSR and TcfSR, suggesting that these TCS proteins could be necessary for the adaptation of Brucella as an intracellular pathogen. This genomic analysis revealed the presence of a differential distribution of TCS pseudogenes among Brucella species...

  9. Potassium is a key signal in host-microbiome dysbiosis in periodontitis.

    Directory of Open Access Journals (Sweden)

    Susan Yost

    2017-06-01

    Full Text Available Dysbiosis, or the imbalance in the structural and/or functional properties of the microbiome, is at the origin of important infectious inflammatory diseases such as inflammatory bowel disease (IBD and periodontal disease. Periodontitis is a polymicrobial inflammatory disease that affects a large proportion of the world's population and has been associated with a wide variety of systemic health conditions, such as diabetes, cardiovascular and respiratory diseases. Dysbiosis has been identified as a key element in the development of the disease. However, the precise mechanisms and environmental signals that lead to the initiation of dysbiosis in the human microbiome are largely unknown. In a series of previous in vivo studies using metatranscriptomic analysis of periodontitis and its progression we identified several functional signatures that were highly associated with the disease. Among them, potassium ion transport appeared to be key in the process of pathogenesis. To confirm its importance we performed a series of in vitro experiments, in which we demonstrated that potassium levels a increased the virulence of the oral community as a whole and at the same time altering the immune response of gingival epithelium, increasing the production of TNF-α and reducing the expression of IL-6 and the antimicrobial peptide human β-defensin 3 (hBD-3. These results indicate that levels of potassium in the periodontal pocket could be an important element in of dysbiosis in the oral microbiome. They are a starting point for the identification of key environmental signals that modify the behavior of the oral microbiome from a symbiotic community to a dysbiotic one.

  10. Signal transduction of Helicobacter pylori during interaction with host cell protein receptors of epithelial and immune cells

    Science.gov (United States)

    Pachathundikandi, Suneesh Kumar; Tegtmeyer, Nicole; Backert, Steffen

    2013-01-01

    Helicobacter pylori infections can induce pathologies ranging from chronic gastritis, peptic ulceration to gastric cancer. Bacterial isolates harbor numerous well-known adhesins, vacuolating cytotoxin VacA, protease HtrA, urease, peptidoglycan, and type IV secretion systems (T4SS). It appears that H. pylori targets more than 40 known host protein receptors on epithelial or immune cells. A series of T4SS components such as CagL, CagI, CagY, and CagA can bind to the integrin α5β1 receptor. Other targeted membrane-based receptors include the integrins αvβ3, αvβ5, and β2 (CD18), RPTP-α/β, GP130, E-cadherin, fibronectin, laminin, CD46, CD74, ICAM1/LFA1, T-cell receptor, Toll-like receptors, and receptor tyrosine kinases EGFR, ErbB2, ErbB3, and c-Met. In addition, H. pylori is able to activate the intracellular receptors NOD1, NOD2, and NLRP3 with important roles in innate immunity. Here we review the interplay of various bacterial factors with host protein receptors. The contribution of these interactions to signal transduction and pathogenesis is discussed. PMID:24280762

  11. Signal transduction of Helicobacter pylori during interaction with host cell protein receptors of epithelial and immune cells.

    Science.gov (United States)

    Pachathundikandi, Suneesh Kumar; Tegtmeyer, Nicole; Backert, Steffen

    2013-01-01

    Helicobacter pylori infections can induce pathologies ranging from chronic gastritis, peptic ulceration to gastric cancer. Bacterial isolates harbor numerous well-known adhesins, vacuolating cytotoxin VacA, protease HtrA, urease, peptidoglycan, and type IV secretion systems (T4SS). It appears that H. pylori targets more than 40 known host protein receptors on epithelial or immune cells. A series of T4SS components such as CagL, CagI, CagY, and CagA can bind to the integrin α 5β 1 receptor. Other targeted membrane-based receptors include the integrins αvβ 3, αvβ 5, and β 2 (CD18), RPTP-α/β, GP130, E-cadherin, fibronectin, laminin, CD46, CD74, ICAM1/LFA1, T-cell receptor, Toll-like receptors, and receptor tyrosine kinases EGFR, ErbB2, ErbB3, and c-Met. In addition, H. pylori is able to activate the intracellular receptors NOD1, NOD2, and NLRP3 with important roles in innate immunity. Here we review the interplay of various bacterial factors with host protein receptors. The contribution of these interactions to signal transduction and pathogenesis is discussed.

  12. Transcriptional regulation by an NAC (NAM-ATAF1,2-CUC2) transcription factor attenuates ABA signalling for efficient basal defence towards Blumeria graminis f. sp. hordei in Arabidopsis.

    Science.gov (United States)

    Jensen, Michael K; Hagedorn, Peter H; de Torres-Zabala, Marta; Grant, Murray R; Rung, Jesper H; Collinge, David B; Lyngkjaer, Michael F

    2008-12-01

    ATAF1 is a member of a largely uncharacterized plant-specific gene family encoding NAC transcription factors, and is induced in response to various abiotic and biotic stimuli in Arabidopsis thaliana. Previously, we showed that a mutant allele of ATAF1 compromises penetration resistance in Arabidopsis with respect to the non-host biotrophic pathogen Blumeria graminis f. sp. hordei (Bgh). In this study, we have used genome-wide transcript profiling to characterize signalling perturbations in ataf1 plants following Bgh inoculation. Comparative transcriptomic analyses identified an over-representation of abscisic acid (ABA)-responsive genes, including the ABA biosynthesis gene AAO3, which is significantly induced in ataf1 plants compared to wild-type plants following inoculation with Bgh. Additionally, we show that Bgh inoculation results in decreased endogenous ABA levels in an ATAF1-dependent manner, and that the ABA biosynthetic mutant aao3 showed increased penetration resistance to Bgh compared to wild-type plants. Furthermore, we show that ataf1 plants show ABA-hyposensitive phenotypes during seedling development and germination. Our data support a negative correlation between ABA levels and penetration resistance, and identify ATAF1 as a new stimuli-dependent attenuator of ABA signalling for the mediation of efficient penetration resistance in Arabidopsis upon Bgh attack.

  13. The reconfiguration of the SA defence industry in the post-2015-defence review environment: prospects & challenges

    CSIR Research Space (South Africa)

    Khanyile, Moses

    2017-10-01

    Full Text Available foundation for an expanded and better balanced industry to support the SANDF. STRATEGIC NATIONAL INITIATIVES (Cont’d) National Defence Industry Council (NDIC) Defence Sector Charter  Gazetted for public comment: 4 Oct 2017  Consultative sessions... among defence analysts, academics and broader defence companies  Introduces various scorecards for designated groups, including military veterans Objective: To promote the growth and sustainability of the Defence Industry by : Products...

  14. Host cell-induced signaling causes Clostridium perfringens to upregulate production of toxins important for intestinal infections

    Science.gov (United States)

    Chen, Jianming; Ma, Menglin; Uzal, Francisco A; McClane, Bruce A

    2014-01-01

    Clostridium perfringens causes enteritis and enterotoxemia in humans and livestock due to prolific toxin production. In broth culture, C. perfringens uses the Agr-like quorum sensing (QS) system to regulate production of toxins important for enteritis/enterotoxemia, including beta toxin (CPB), enterotoxin, and epsilon toxin (ETX). The VirS/VirR two-component regulatory system (TCRS) also controls CPB production in broth cultures. Both the Agr-like QS and VirS/VirR systems are important when C. perfringens senses enterocyte-like Caco-2 cells and responds by upregulating CPB production; however, only the Agr-like QS system is needed for host cell-induced ETX production. These in vitro observations have pathophysiologic relevance since both the VirS/VirR and Agr-like QS signaling systems are required for C. perfringens strain CN3685 to produce CPB in vivo and to cause enteritis or enterotoxemia. Thus, apparently upon sensing its presence in the intestines, C. perfringens utilizes QS and TCRS signaling to produce toxins necessary for intestinal virulence. PMID:24061146

  15. Complement in disease: a defence system turning offensive.

    Science.gov (United States)

    Ricklin, Daniel; Reis, Edimara S; Lambris, John D

    2016-07-01

    Although the complement system is primarily perceived as a host defence system, a more versatile, yet potentially more harmful side of this innate immune pathway as an inflammatory mediator also exists. The activities that define the ability of the complement system to control microbial threats and eliminate cellular debris - such as sensing molecular danger patterns, generating immediate effectors, and extensively coordinating with other defence pathways - can quickly turn complement from a defence system to an aggressor that drives immune and inflammatory diseases. These host-offensive actions become more pronounced with age and are exacerbated by a variety of genetic factors and autoimmune responses. Complement can also be activated inappropriately, for example in response to biomaterials or transplants. A wealth of research over the past two decades has led to an increasingly finely tuned understanding of complement activation, identified tipping points between physiological and pathological behaviour, and revealed avenues for therapeutic intervention. This Review summarizes our current view of the key activating, regulatory, and effector mechanisms of the complement system, highlighting important crosstalk connections, and, with an emphasis on kidney disease and transplantation, discusses the involvement of complement in clinical conditions and promising therapeutic approaches.

  16. The role of cell signaling in poxvirus tropism: the case of the M-T5 host range protein of myxoma virus.

    Science.gov (United States)

    Werden, Steven J; McFadden, Grant

    2008-01-01

    Poxviruses demonstrate strict species specificity in vivo that range from narrow to broad, however the fundamental factors that mediate the basis of poxvirus tropism remain poorly understood. It is generally believed that most, if not all, poxviruses can efficiently bind and enter a wide range of mammalian cells and all of the known host anti-viral pathways that block viral replication in nonpremissive cells operate downstream of virus entry. A productive poxvirus infection is heavily dependent upon the production of a vast array of host modulatory products that specifically target and manipulate both extracellular immune response pathways of the host, as well as intracellular signal transduction pathways of the individually infected cells. The unique pathogenesis and host tropism of specific poxviruses can be attributed to the broad diversity of host modulatory proteins they express. Myxoma virus (MV) is a rabbit-specific poxviruses that encodes multiple host range factors, including an ankyrin-repeat protein M-T5, which functions to regulate tropism of MV for rabbit lymphocytes and some human cancer cells. At the molecular level, M-T5 binds and alters at least two distinct cellular proteins: Akt and cullin-1. The direct interaction between M-T5 and Akt was shown to be a key restriction determinant for MV tropism in a spectrum of human cancer cells making MV an excellent oncolytic candidate. Thus, the intricate relationship between viral encoded proteins and components of the host cell signaling networks can have profound impact on poxvirus tropism. The lessons we continue to learn from poxvirus host range factors like M-T5 will provide further insights into the factors that regulate poxvirus tropism and the mechanisms by which poxviruses micromanipulate the signaling pathways of the infected cell.

  17. Susceptibility and Immune Defence Mechanisms of Rhynchophorus ferrugineus (Olivier (Coleoptera: Curculionidae against Entomopathogenic Fungal Infections

    Directory of Open Access Journals (Sweden)

    Abid Hussain

    2016-09-01

    Full Text Available Insects infected with entomopathogenic fungi, experience physiological changes that influence their growth and immune defence. The potential of nine isolates of entomopathogenic fungi was evaluated after determining percent germination and relative conidial hydrophobicity. However, nutritional indices were evaluated after immersing eighth-instar Rhynchophorus ferrugineus larvae into each isolate suspension (1 × 107 conidia/mL. The results showed that isolates B6884 and M9374 had 44.51% and 39.02% higher conidial hydrophobicity compared with isolate I03011 (least virulent. The results of nutritional index assays revealed a significant reduction in growth indices after infection with different isolates. Compared with control, B6884 and M9374 greatly decreased larval growth by reducing the efficacy of conversion of ingested food (36%–47% and Efficacy of conversion of digested food (50%–63%. Furthermore, only isolate B6884 induced 100% mortality within 12 days. Compared with control, isolate I03011, possessing the lowest conidial hydrophobicity, only reduced 0.29% of the efficacy of conversion of ingested food (ECI and 0.48% of the efficacy of conversion of digested food (ECD. Similarly, transcriptomic analysis of genes related to the Red palm weevil (RPW immune response, including pathogen recognition receptors (C-type lectin and endo-beta-1,4-glucanse, signal modulator (Serine protease-like protein, signal transductors (Calmodulin-like protein and EF-hand domain containing protein and effectors (C-type lysozyme, Cathepsin L., Defensin-like protein, Serine carboxypeptidase, and Thaumatin-like protein, was significantly increased in larval samples infected with B6884 and M9374. These results suggest that for an isolate to be virulent, conidial hydrophobicity and germination should also be considered during pathogen selection, as these factors could significantly impact host growth and immune defence mechanisms.

  18. The psychiatric defence and international criminal law.

    Science.gov (United States)

    Tobin, John

    2007-01-01

    Following the development of the International Criminal Court (ICC) the mental state of the perpetrators of genocide, crimes against humanity and war crimes will become a more important issue in regard to defence and mitigating factors. This article examines how the International Criminal Tribunal for the Former Yugoslavia (ICTY) in particular has dealt with the mental illness defence to date, and how its judgements can serve as guidance for the ICC as it becomes the major international court of the future. The absence of a mental health defence in the Statutes of the ICTY and the International Criminal Tribunal for Rwanda has led to a reliance on the Rules of Procedure and Evidence of the two tribunals. There are major difficulties in using the mental health defence as it is defined in the Statutes of the ICC because of a requirement for the destruction of mental capacity as a valid defence. Fitness to plead and the defence of intoxication are also examined.

  19. Defence counsel in international criminal law

    OpenAIRE

    Temminck Tuinstra, J.P.W.

    2009-01-01

    The field of international criminal law is relatively new and rapidly developing. This dissertation examines whether international criminal courts enable defence counsel to conduct an effective defence. When the International Criminal Tribunals for the former Yugoslavia and Rwanda (the ad hoc Tribunals) were set up in the mid-nineties to prosecute those responsible for serious violations of international humanitarian law, not much thought had been given to the organisation of the defence. The...

  20. Piloting Snapchat for Finnish Defence Forces

    OpenAIRE

    Immonen, Helena

    2016-01-01

    This thesis is about piloting Snapchat for Finnish Defence Forces. The goals for the thesis are to find out how Snapchat can be used as part of Finnish Defence Forces’ social media communication and strategy. Conscripts are the most important target group for social media communication in the Defence Forces. Young conscripts are the main target group for Snapchat. This thesis is theoretically based on organizational communication, stakeholder communication and social media communicati...

  1. Ecological trade-offs between jasmonic acid-dependent direct and indirect plant defences in tritrophic interactions

    National Research Council Canada - National Science Library

    Jianing Wei; Lizhong Wang; Jiuhai Zhao; Chuanyou Li; Feng Ge; Le Kang

    2011-01-01

    Recent studies on plants genetically modified in jasmonic acid (JA) signalling support the hypothesis that the jasmonate family of oxylipins plays an important role in mediating direct and indirect plant defences...

  2. Two thiadiazole compounds promote rice defence against Xanthomonas oryzae pv. oryzae by suppressing the bacterium's production of extracellular polysaccharides.

    Science.gov (United States)

    Liang, Xiaoyu; Yu, Xiaoyue; Dong, Wenxia; Guo, Shijian; Xu, Shu; Wang, Jianxin; Zhou, Mingguo

    2015-10-01

    Thiazole, isothiazole, thiadiazole, and their derivatives are used to control various human, animal and plant diseases. In addition to having direct anti-microbial and anti-fungal properties, these compounds are thought to induce host defences, but the mechanism of defence induction remains poorly understood. This article reports that the thiadiazoles of zinc thiazole and bismerthiazol induce H2 O2 accumulation, up-regulation of defence-related genes, callose deposition and hypersensitive response-like cell death in rice leaves infected with Xanthomonas oryaze pv. oryzae (Xoo) strain ZJ173, but not in non-infected leaves. These defence responses in Xoo-infected leaves were suppressed by the exogenous application of catalase, which reduces H2 O2 accumulation. The application of extracellular polysaccharides (EPSs) extracted from strain ZJ173 significantly compromised rice defence against ZJ173 with or without thiadiazole treatment. The EPS-deficient Xoo mutant ∆gumH triggered a stronger defence than its parent strain ZJ173. The thiadiazole treatments reduced EPS production by strain ZJ173, but not by the thiadiazole-resistant strain 2-1-1, which is thiadiazole resistant in vivo, but not in vitro; moreover, enhanced defence was not detected in thiadiazole-treated rice inoculated with 2-1-1. Based on these data, we infer that zinc thiazole and bismerthiazol promote rice defence against Xoo by inhibiting the production of bacterial EPS. © 2015 BSPP AND JOHN WILEY & SONS LTD.

  3. Recent host range expansion of canine distemper virus and variation in its receptor, the signaling lymphocyte activation molecule, in carnivores.

    Science.gov (United States)

    Ohishi, Kazue; Suzuki, Rintaro; Maeda, Taro; Tsuda, Miwako; Abe, Erika; Yoshida, Takao; Endo, Yasuyuki; Okamura, Maki; Nagamine, Takashi; Yamamoto, Hanae; Ueda, Miya; Maruyama, Tadashi

    2014-07-01

    The signaling lymphocyte activation molecule (SLAM) is a receptor for morbilliviruses. To understand the recent host range expansion of canine distemper virus (CDV) in carnivores, we determined the nucleotide sequences of SLAMs of various carnivores and generated three-dimensional homology SLAM models. Thirty-four amino acid residues were found for the candidates binding to CDV on the interface of the carnivore SLAMs. SLAM of the domestic dog (Canis lupus familiaris) were similar to those of other members of the suborder Caniformia, indicating that the animals in this group have similar sensitivity to dog CDV. However, they were different at nine positions from those of felids. Among the nine residues, four of domestic cat (Felis catus) SLAM (72, 76, 82, and 129) and three of lion (Panthera leo persica) SLAM (72, 82, and 129) were associated with charge alterations, suggesting that the felid interfaces have lower affinities to dog CDV. Only the residue at 76 was different between domestic cat and lion SLAM interfaces. The domestic cat SLAM had threonine at 76, whereas the lion SLAM had arginine, a positively charged residue like that of the dog SLAM. The cat SLAM with threonine is likely to have lower affinity to CDV-H and to confer higher resistance against dog CDV. Thus, the four residues (72, 76, 82, and 129) on carnivore SLAMs are important for the determination of affinity and sensitivity with CDV. Additionally, the CDV-H protein of felid strains had a substitution of histidine for tyrosine at 549 of dog CDV-H and may have higher affinity to lion SLAM. Three-dimensional model construction is a new risk assessment method of morbillivirus infectivity. Because the method is applicable to animals that have no information about virus infection, it is especially useful for morbillivirus risk assessment and wildlife conservation.

  4. A Novel Two-Component Signaling System Facilitates Uropathogenic Escherichia coli's Ability to Exploit Abundant Host Metabolites

    Science.gov (United States)

    Cai, Wentong; Wannemuehler, Yvonne; Dell'Anna, Giuseppe; Nicholson, Bryon; Barbieri, Nicolle L.; Kariyawasam, Subhashinie; Feng, Yaping; Logue, Catherine M.; Nolan, Lisa K.; Li, Ganwu

    2013-01-01

    Two-component signaling systems (TCSs) are major mechanisms by which bacteria adapt to environmental conditions. It follows then that TCSs would play important roles in the adaptation of pathogenic bacteria to host environments. However, no pathogen-associated TCS has been identified in uropathogenic Escherichia coli (UPEC). Here, we identified a novel TCS, which we termed KguS/KguR (KguS: α-ketoglutarate utilization sensor; KguR: α-ketoglutarate utilization regulator) in UPEC CFT073, a strain isolated from human pyelonephritis. kguS/kguR was strongly associated with UPEC but was found only rarely among other E. coli including commensal and intestinal pathogenic strains. An in vivo competition assay in a mouse UTI model showed that deletion of kguS/kguR in UPEC CFT073 resulted in a significant reduction in its colonization of the bladders and kidneys of mice, suggesting that KguS/KguR contributed to UPEC fitness in vivo. Comparative proteomics identified the target gene products of KguS/KguR, and sequence analysis showed that TCS KguS/KguR and its targeted-genes, c5032 to c5039, are encoded on a genomic island, which is not present in intestinal pathogenic E. coli. Expression of the target genes was induced by α-ketoglutarate (α-KG). These genes were further shown to be involved in utilization of α-KG as a sole carbon source under anaerobic conditions. KguS/KguR contributed to the regulation of the target genes with the direct regulation by KguR verified using an electrophoretic mobility shift assay. In addition, oxygen deficiency positively modulated expression of kguS/kguR and its target genes. Taken altogether, this study describes the first UPEC-associated TCS that functions in controlling the utilization of α-ketoglutarate in vivo thereby facilitating UPEC adaptation to life inside the urinary tract. PMID:23825943

  5. A novel two-component signaling system facilitates uropathogenic Escherichia coli's ability to exploit abundant host metabolites.

    Directory of Open Access Journals (Sweden)

    Wentong Cai

    Full Text Available Two-component signaling systems (TCSs are major mechanisms by which bacteria adapt to environmental conditions. It follows then that TCSs would play important roles in the adaptation of pathogenic bacteria to host environments. However, no pathogen-associated TCS has been identified in uropathogenic Escherichia coli (UPEC. Here, we identified a novel TCS, which we termed KguS/KguR (KguS: α-ketoglutarate utilization sensor; KguR: α-ketoglutarate utilization regulator in UPEC CFT073, a strain isolated from human pyelonephritis. kguS/kguR was strongly associated with UPEC but was found only rarely among other E. coli including commensal and intestinal pathogenic strains. An in vivo competition assay in a mouse UTI model showed that deletion of kguS/kguR in UPEC CFT073 resulted in a significant reduction in its colonization of the bladders and kidneys of mice, suggesting that KguS/KguR contributed to UPEC fitness in vivo. Comparative proteomics identified the target gene products of KguS/KguR, and sequence analysis showed that TCS KguS/KguR and its targeted-genes, c5032 to c5039, are encoded on a genomic island, which is not present in intestinal pathogenic E. coli. Expression of the target genes was induced by α-ketoglutarate (α-KG. These genes were further shown to be involved in utilization of α-KG as a sole carbon source under anaerobic conditions. KguS/KguR contributed to the regulation of the target genes with the direct regulation by KguR verified using an electrophoretic mobility shift assay. In addition, oxygen deficiency positively modulated expression of kguS/kguR and its target genes. Taken altogether, this study describes the first UPEC-associated TCS that functions in controlling the utilization of α-ketoglutarate in vivo thereby facilitating UPEC adaptation to life inside the urinary tract.

  6. CSIR eNews: Defence peace safety and security

    CSIR Research Space (South Africa)

    CSIR

    2008-12-01

    Full Text Available in defence, peace, safety and security. CSIR DPSS provides a national defence S&T capability: supplying knowledge, advice and solutions in defence and matters of national security....

  7. CSIR eNews: Defence, peace, safety and security

    CSIR Research Space (South Africa)

    CSIR

    2007-12-01

    Full Text Available , peace, safety and security. CSIR Defence, Peace, Safety and Security provides a national defence S&T capability: supplying knowledge, advice and solutions in defence and matters of national security....

  8. Defence strategies against a parasitoid wasp in Drosophila: fight or flight?

    Science.gov (United States)

    Lefèvre, Thierry; de Roode, Jacobus C; Kacsoh, Balint Z; Schlenke, Todd A

    2012-04-23

    Hosts may defend themselves against parasitism through a wide variety of defence mechanisms, but due to finite resources, investment in one defence mechanism may trade-off with investment in another mechanism. We studied resistance strategies against the parasitoid wasp Leptopilina boulardi in two Drosophila species. We found that D. melanogaster had significantly lower physiological resistance against L. boulardi than D. simulans, and hypothesized that D. melanogaster might instead invest more heavily in other forms of defence, such as behavioural defence. We found that when given a choice between clean oviposition sites and sites infested with wasps, both D. melanogaster and D. simulans detected and avoided infested sites, which presumably limits later exposure of their offspring to infection. Unlike D. simulans, however, D. melanogaster laid significantly fewer eggs than controls in the forced presence of wasps. Our findings suggest that D. melanogaster relies more heavily on behavioural avoidance as defence against wasp parasitism than D. simulans, and that this may compensate for a lack of physiological defence.

  9. A Comparative Analysis of Sonic Defences in Bombycoidea Caterpillars.

    Science.gov (United States)

    Bura, Veronica L; Kawahara, Akito Y; Yack, Jayne E

    2016-08-11

    Caterpillars have long been used as models for studying animal defence. Their impressive armour, including flamboyant warning colours, poisonous spines, irritating sprays, and mimicry of plant parts, snakes and bird droppings, has been extensively documented. But research has mainly focused on visual and chemical displays. Here we show that some caterpillars also exhibit sonic displays. During simulated attacks, 45% of 38 genera and 33% of 61 species of silk and hawkmoth caterpillars (Bombycoidea) produced sounds. Sonic caterpillars are found in many distantly-related groups of Bombycoidea, and have evolved four distinct sound types- clicks, chirps, whistles and vocalizations. We propose that different sounds convey different messages, with some designed to warn of a chemical defence and others, to startle predators. This research underscores the importance of exploring acoustic communication in juvenile insects, and provides a model system to explore how different signals have evolved to frighten, warn or even trick predators.

  10. South Africa's Defence Industrial Participation in Perspective

    African Journals Online (AJOL)

    jvdyk

    2014-03-31

    Mar 31, 2014 ... civil purchases (e.g. passenger aircraft).3 As a result of the biggest defence transaction in. South Africa, the Strategic Defence Package. (SDP) of December 1999, incurred R15 billion worth of DIP obligations. This article. Scientia Militaria, South African. Journal of Military Studies, Vol. 44, No. 2, 2016, pp.

  11. The Parliamentary Dimension of Defence Cooperation

    NARCIS (Netherlands)

    Bakker, Anne; Drent, Margriet; Landman, Lennart

    2016-01-01

    Europe’s unprecedented security challenges call for a step change in the EU’s approach to security and defence. This Clingendael report reflects the main topics of discussion at the high-level Netherlands EU Presidency Seminar on Defence held on 20 and 21 January 2016. The new EU Global Strategy on

  12. The South African National Defence Force

    DEFF Research Database (Denmark)

    Mandrup, Thomas

    2009-01-01

    This research paper is an evaluation of The Souch African National Defence Force´s (SANDF) involvement in Peace Support Operations.......This research paper is an evaluation of The Souch African National Defence Force´s (SANDF) involvement in Peace Support Operations....

  13. Plant defences against herbivore and insect attack

    Science.gov (United States)

    Plants deploy a number of defences against attack by insects and other herbivores. Direct defence is conferred by plant products and structures that deter or kill the herbivores. Chemical toxins and deterrents vary widely among plant species, and some typical toxins include alkaloids, terpenoids, st...

  14. Defence counsel in international criminal law

    NARCIS (Netherlands)

    Temminck Tuinstra, J.P.W.

    2009-01-01

    The field of international criminal law is relatively new and rapidly developing. This dissertation examines whether international criminal courts enable defence counsel to conduct an effective defence. When the International Criminal Tribunals for the former Yugoslavia and Rwanda (the ad hoc

  15. Failure probability of regional flood defences

    NARCIS (Netherlands)

    Lendering, K.T.; lang, M.; Klijn, F.; Samuels, P.

    2016-01-01

    Polders in the Netherlands are protected from flooding by primary and regional flood defence systems. During the last decade, scientific research in flood risk focused on the development of a probabilistic approach to quantify the probability of flooding of the primary flood defence system. This

  16. Invited Lecture: From Host Defence Peptides to New Antibiotics

    DEFF Research Database (Denmark)

    Hansen, Paul Robert

    of these antimicrobial peptides, which enables us to better understand their mechanism of action and facilitates the development of lead antimicrobial agents. As an example, in this talk I will focus on our work on anoplin and analogues, a decapeptide isolated from the Japanese wasp Anoplius samariensis. I will describe...... the elucidation of their structure/activity relationships, and our efforts towards developing them into antibiotics.......Antimicrobial peptides hold promise as the next generation of antimicrobial agents. However, the potential is weakened by their susceptibility to proteolytic degradation, poor bioavailabillity , toxicity and high cost. Our research interest is in determining the structure/activity relationships...

  17. Bacteriophages use hypermodified nucleosides to evade host's defence systems

    DEFF Research Database (Denmark)

    Kot, Witold; Olsen, Nikoline S.; Carstens, Alexander Byth

     Seuratvirus genus. CAjan contains a set of genes with a high degree of similarity to 7-deazapurine biosynthesis genes. 7-deazapurines are hypermodified nucleosides, which are present in some classes of RNAs in bacteria and eukaryotes. CAjan show a remarkable resistance to restriction endonucleases.  In order...... to investigate this mechanism in detail we have used several methods including direct plaque sequencing, restriction endonuclease analysis and CRISPR-Cas genome editing. Through generation of specific mutants, we were able to introduce a restriction sensitive phenotype in the CAjan bacteriophage providing new......Since the very beginning of life, primitive cells were forced to face selfish genetic elements like viruses or plasmids. Bacteria, continually exposed to infections, developed several phage resistance mechanisms e.g. restriction-modification and CRISPR-Cas systems. On the other hand, bacteriophages...

  18. Light exposure at night disrupts host/cancer circadian regulatory dynamics: impact on the Warburg effect, lipid signaling and tumor growth prevention.

    Directory of Open Access Journals (Sweden)

    David E Blask

    Full Text Available The central circadian clock within the suprachiasmatic nucleus (SCN plays an important role in temporally organizing and coordinating many of the processes governing cancer cell proliferation and tumor growth in synchrony with the daily light/dark cycle which may contribute to endogenous cancer prevention. Bioenergetic substrates and molecular intermediates required for building tumor biomass each day are derived from both aerobic glycolysis (Warburg effect and lipid metabolism. Using tissue-isolated human breast cancer xenografts grown in nude rats, we determined that circulating systemic factors in the host and the Warburg effect, linoleic acid uptake/metabolism and growth signaling activities in the tumor are dynamically regulated, coordinated and integrated within circadian time structure over a 24-hour light/dark cycle by SCN-driven nocturnal pineal production of the anticancer hormone melatonin. Dim light at night (LAN-induced melatonin suppression disrupts this circadian-regulated host/cancer balance among several important cancer preventative signaling mechanisms, leading to hyperglycemia and hyperinsulinemia in the host and runaway aerobic glycolysis, lipid signaling and proliferative activity in the tumor.

  19. Loss of Host Type-I IFN Signaling Accelerates Metastasis and Impairs NK-cell Antitumor Function in Multiple Models of Breast Cancer.

    Science.gov (United States)

    Rautela, Jai; Baschuk, Nikola; Slaney, Clare Y; Jayatilleke, Krishnath M; Xiao, Kun; Bidwell, Bradley N; Lucas, Erin C; Hawkins, Edwin D; Lock, Peter; Wong, Christina S; Chen, Weisan; Anderson, Robin L; Hertzog, Paul J; Andrews, Daniel M; Möller, Andreas; Parker, Belinda S

    2015-11-01

    Metastatic progression is the major cause of breast cancer-related mortality. By examining multiple syngeneic preclinical breast cancer models in mice lacking a functional type-I interferon receptor (Ifnar1(-/-) mice), we show that host-derived type-I interferon (IFN) signaling is a critical determinant of metastatic spread that is independent of primary tumor growth. In particular, we show that bone metastasis can be accelerated in Balb/c Ifnar1(-/-) mice bearing either 4T1 or 66cl4 orthotopic tumors and, for the first time, present data showing the development of bone metastasis in the C57Bl/6 spontaneous MMTV-PyMT-driven model of tumorigenesis. Further exploration of these results revealed that endogenous type-I IFN signaling to the host hematopoietic system is a key determinant of metastasis-free survival and critical to the responsiveness of the circulating natural killer (NK)-cell population. We find that in vivo-stimulated NK cells derived from wild-type, but not Ifnar1(-/-), mice can eliminate the 4T1 and 66cl4 breast tumor lines with varying kinetics in vitro. Together, this study indicates that the dysregulated immunity resulting from a loss of host type-I IFN signaling is sufficient to drive metastasis, and provides a rationale for targeting the endogenous type-I IFN pathway as an antimetastatic strategy. ©2015 American Association for Cancer Research.

  20. Failure probability of regional flood defences

    Directory of Open Access Journals (Sweden)

    Lendering Kasper

    2016-01-01

    Full Text Available Polders in the Netherlands are protected from flooding by primary and regional flood defence systems. During the last decade, scientific research in flood risk focused on the development of a probabilistic approach to quantify the probability of flooding of the primary flood defence system. This paper proposed a methodology to quantify the probability of flooding of regional flood defence systems, which required several additions to the methodology used for the primary flood defence system. These additions focused on a method to account for regulation of regional water levels, the possibility of (reduced intrusion resistance due to maintenance dredging in regional water, the probability of traffic loads and the influence of dependence between regional water levels and the phreatic surface of a regional flood defence. In addition, reliability updating is used to demonstrate the potential for updating the probability of failure of regional flood defences with performance observations. The results demonstrated that the proposed methodology can be used to determine the probability of flooding of a regional flood defence system. In doing so, the methodology contributes to improving flood risk management in these systems.

  1. The Drosophila melanogaster host model

    Science.gov (United States)

    Igboin, Christina O.; Griffen, Ann L.; Leys, Eugene J.

    2012-01-01

    The deleterious and sometimes fatal outcomes of bacterial infectious diseases are the net result of the interactions between the pathogen and the host, and the genetically tractable fruit fly, Drosophila melanogaster, has emerged as a valuable tool for modeling the pathogen–host interactions of a wide variety of bacteria. These studies have revealed that there is a remarkable conservation of bacterial pathogenesis and host defence mechanisms between higher host organisms and Drosophila. This review presents an in-depth discussion of the Drosophila immune response, the Drosophila killing model, and the use of the model to examine bacterial–host interactions. The recent introduction of the Drosophila model into the oral microbiology field is discussed, specifically the use of the model to examine Porphyromonas gingivalis–host interactions, and finally the potential uses of this powerful model system to further elucidate oral bacterial-host interactions are addressed. PMID:22368770

  2. Epigenetic modulation of host: new insights into immune evasion by ...

    Indian Academy of Sciences (India)

    Viruses have evolved with their hosts, which include all living species. This has been partly responsible for the development of highly advanced immune systems in the hosts. However, viruses too have evolved ways to regulate and evade the host's immune defence. In addition to mutational mechanisms that viruses employ ...

  3. Defence Capability Plan 2006-2016

    National Research Council Canada - National Science Library

    2006-01-01

    The Defence Capability Plan: Public Version 2006-2016 (DCP 2006-16) provides a brief account of major capital equipment proposals that are currently planned to be approved in the period 2006 to 2016...

  4. The mechanical defence advantage of small seeds.

    Science.gov (United States)

    Fricke, Evan C; Wright, S Joseph

    2016-08-01

    Seed size and toughness affect seed predators, and size-dependent investment in mechanical defence could affect relationships between seed size and predation. We tested how seed toughness and mechanical defence traits (tissue density and protective tissue content) are related to seed size among tropical forest species. Absolute toughness increased with seed size. However, smaller seeds had higher specific toughness both within and among species, with the smallest seeds requiring over 2000 times more energy per gram to break than the largest seeds. Investment in mechanical defence traits varied widely but independently of the toughness-mass allometry. Instead, a physical scaling relationship confers a toughness advantage on small seeds independent of selection on defence traits and without a direct cost. This scaling relationship may contribute to seed size diversity by decreasing fitness differences among large and small seeds. Allometric scaling of toughness reconciles predictions and conflicting empirical relationships between seed size and predation. © 2016 John Wiley & Sons Ltd/CNRS.

  5. Driving Danish Defence Towards Political Goals

    Science.gov (United States)

    2016-06-10

    Scientist’s Perspective ........................................................................................... 24 Kotter’s Eight-step Change Model ...structure of the Danish Defence, the underlying perspective in this thesis will be based on social constructivism . According to John W. Creswell...

  6. Comparative perspectives on East and West European defence industries

    OpenAIRE

    Kenny, Brian

    2001-01-01

    Coupled with the continuing threat of reduced defence expenditures and increasing competition, European defence companies have reacted with a number of strategic manoeuvres involving mergers, acquisitions and other forms of alliance. Moves towards a single European defence industry have been a focus for discussion among major EU member countries for some time and the integration of defence aerospace organisations seems well placed to succeed with the advent of EADS. Defence industry firms and...

  7. UK photonics in defence and security

    Science.gov (United States)

    Gracie, C.; Tooley, I.; Wilson, A.

    2008-10-01

    The UK is globally recognised as strong in Photonics. However its Photonics sector is fragmented and the size and sectors of interest have not previously been established. The UK government has instigated the formation of the Photonics Knowledge Transfer Network (PKTN) to bring the Photonics community together. The UK features in Defence & Security; Communications; Measurement; Medical Technology; Lighting; Solar Energy; Information Technology and Flat Panels. This expertise is scattered through out the UK in geographic areas each with a breadth of Photonic interests. The PKTN has mapped the UK capability in all Photonics sectors. This paper will present the capability of the Companies, Research Institutions and Infrastructure making up the Defence & Security Photonics scene in the UK. Large Defence companies in the UK are well known throughout the world. However, there are a large number of SMEs, which may not be as well known in the supply chain. These are being actively encouraged by the UK MoD to engage with the Defence & Security Market and shall be discussed here. The presentation will reference a number of organisations which help to fund and network the community, such as the Defence Technology Centres. In addition the Roadmap for Defence & Security in the UK, produced for the UK Photonics Strategy (July 2006) by the Scottish Optoelectronics Association will be described and the plans in taking it forward under the PKTN will be revealed.

  8. Transcriptional Analysis of Murine Macrophages Infected with Different Toxoplasma Strains Identifies Novel Regulation of Host Signaling Pathways

    Science.gov (United States)

    Melo, Mariane B.; Nguyen, Quynh P.; Cordeiro, Cynthia; Hassan, Musa A.; Yang, Ninghan; McKell, Renée; Rosowski, Emily E.; Julien, Lindsay; Butty, Vincent; Dardé, Marie-Laure; Ajzenberg, Daniel; Fitzgerald, Katherine; Young, Lucy H.; Saeij, Jeroen P. J.

    2013-01-01

    Most isolates of Toxoplasma from Europe and North America fall into one of three genetically distinct clonal lineages, the type I, II and III lineages. However, in South America these strains are rarely isolated and instead a great variety of other strains are found. T. gondii strains differ widely in a number of phenotypes in mice, such as virulence, persistence, oral infectivity, migratory capacity, induction of cytokine expression and modulation of host gene expression. The outcome of toxoplasmosis in patients is also variable and we hypothesize that, besides host and environmental factors, the genotype of the parasite strain plays a major role. The molecular basis for these differences in pathogenesis, especially in strains other than the clonal lineages, remains largely unexplored. Macrophages play an essential role in the early immune response against T. gondii and are also the cell type preferentially infected in vivo. To determine if non-canonical Toxoplasma strains have unique interactions with the host cell, we infected murine macrophages with 29 different Toxoplasma strains, representing global diversity, and used RNA-sequencing to determine host and parasite transcriptomes. We identified large differences between strains in the expression level of known parasite effectors and large chromosomal structural variation in some strains. We also identified novel strain-specifically regulated host pathways, including the regulation of the type I interferon response by some atypical strains. IFNβ production by infected cells was associated with parasite killing, independent of interferon gamma activation, and dependent on endosomal Toll-like receptors in macrophages and the cytoplasmic receptor retinoic acid-inducible gene 1 (RIG-I) in fibroblasts. PMID:24367253

  9. A novel method for inducing nerve growth via modulation of host resting potential: gap junction-mediated and serotonergic signaling mechanisms.

    Science.gov (United States)

    Blackiston, Douglas J; Anderson, George M; Rahman, Nikita; Bieck, Clara; Levin, Michael

    2015-01-01

    A major goal of regenerative medicine is to restore the function of damaged or missing organs through the implantation of bioengineered or donor-derived components. It is necessary to understand the signals and cues necessary for implanted structures to innervate the host, as organs devoid of neural connections provide little benefit to the patient. While developmental studies have identified neuronal pathfinding molecules required for proper patterning during embryogenesis, strategies to initiate innervation in structures transplanted at later times or alternate locations remain limited. Recent work has identified membrane resting potential of nerves as a key regulator of growth cone extension or arrest. Here, we identify a novel role of bioelectricity in the generation of axon guidance cues, showing that neurons read the electric topography of surrounding cells, and demonstrate these cues can be leveraged to initiate sensory organ transplant innervation. Grafts of fluorescently labeled embryological eye primordia were used to produce ectopic eyes in Xenopus laevis tadpoles. Depolarization of host tissues through anion channel activation or other means led to a striking hyperinnervation of the body by these ectopic eyes. A screen of possible transduction mechanisms identified serotonergic signaling to be essential for hyperinnervation to occur, and our molecular data suggest a possible model of bioelectrical control of the distribution of neurotransmitters that guides nerve growth. Together, these results identify the molecular components of bioelectrical signaling among cells that regulates axon guidance, and suggest novel biomedical and bioengineering strategies for triggering neuronal outgrowth using ion channel drugs already approved for human use.

  10. Hepacivirus NS3/4A Proteases Interfere with MAVS Signaling in both Their Cognate Animal Hosts and Humans: Implications for Zoonotic Transmission.

    Science.gov (United States)

    Anggakusuma; Brown, Richard J P; Banda, Dominic H; Todt, Daniel; Vieyres, Gabrielle; Steinmann, Eike; Pietschmann, Thomas

    2016-12-01

    Multiple novel members of the genus Hepacivirus have recently been discovered in diverse mammalian species. However, to date, their replication mechanisms and zoonotic potential have not been explored in detail. The NS3/4A serine protease of hepatitis C virus (HCV) is critical for cleavage of the viral polyprotein. It also cleaves the cellular innate immune adaptor MAVS, thus decreasing interferon (IFN) production and contributing to HCV persistence in the human host. To investigate the conservation of fundamental aspects of the hepaciviral life cycle, we explored if MAVS cleavage and suppression of innate immune signaling represent a common mechanism employed across different clades of the genus Hepacivirus to enhance viral replication. To estimate the zoonotic potential of these nonhuman hepaciviruses, we assessed if their NS3/4A proteases were capable of cleaving human MAVS. NS3/4A proteases of viruses infecting colobus monkeys, rodents, horses, and cows cleaved the MAVS proteins of their cognate hosts and interfered with the ability of MAVS to induce the IFN-β promoter. All NS3/4A proteases from nonhuman viruses readily cleaved human MAVS. Thus, NS3/4A-dependent cleavage of MAVS is a conserved replication strategy across multiple clades within the genus Hepacivirus Human MAVS is susceptible to cleavage by these nonhuman viral proteases, indicating that it does not pose a barrier for zoonotic transmission of these viruses to humans. Virus infection is recognized by cellular sensor proteins triggering innate immune signaling and antiviral defenses. While viruses have evolved strategies to thwart these antiviral programs in their cognate host species, these evasion mechanisms are often ineffective in a novel host, thus limiting viral transmission across species. HCV, the best-characterized member of the genus Hepacivirus within the family Flaviviridae, uses its NS3/4A protease to disrupt innate immune signaling by cleaving the cellular adaptor protein MAVS

  11. Mapping Type IV Secretion Signals on the Primase Encoded by the Broad-Host-Range Plasmid R1162 (RSF1010).

    Science.gov (United States)

    Meyer, Richard

    2015-10-01

    The plasmid R1162 (RSF1010) encodes a primase essential for its replication. This primase makes up the C-terminal part of MobA, a multifunctional protein with the relaxase as a separate N-terminal domain. The primase is also translated separately as the protein RepB'. Here, we map two signals for type IV secretion onto the recently solved structure of RepB'. One signal is located internally within RepB' and consists of a long α-helix and an adjacent disordered region rich in arginines. The second signal is made up of the same α-helix and a second, arginine-rich region at the C-terminal end of the protein. Successive arginine-to-alanine substitutions revealed that either signal can be utilized by the type IV secretion complex of the plasmid R751. The internal signal also enables conjugal transfer when linked to the relaxase part of MobA. Both signals are similar to those previously identified for type IV secretion substrates in the Vir system of Agrobacterium tumefaciens. Moreover, the C-terminal arginine-rich segment of RepB' has been shown to be secreted by Vir. However, with R751, the signals require MobB, an R1162-encoded accessory protein active in conjugal transfer. The results of two-hybrid assays revealed that MobB interacts, via its membrane-associated domain, with the R751 plasmid coupling protein TraG. In addition, MobB interacts with a region of MobA just outside the RepB' domain. Therefore, MobB is likely an adaptor that is essential for recognition of the primase-associated signals by the R751 secretion machinery. For most plasmids, type IV secretion is an intrinsic part of the mechanism for conjugal transfer. Protein relaxases, bound to the 5' end of the transferring strand, are mobilized into recipient cells by the type IV pathway. In this work, we identify and characterize two signals for secretion in the primase domain of MobA, the relaxase of the IncQ plasmid R1162 (RSF1010). We also show that the adaptor protein MobB is required for engagement

  12. Leptosphaeria maculans effector AvrLm4-7 affects salicylic acid (SA) and ethylene (ET) signalling and hydrogen peroxide (H2 O2 ) accumulation in Brassica napus.

    Science.gov (United States)

    Nováková, Miroslava; Šašek, Vladimír; Trdá, Lucie; Krutinová, Hana; Mongin, Thomas; Valentová, Olga; Balesdent, Marie-HelEne; Rouxel, Thierry; Burketová, Lenka

    2016-08-01

    To achieve host colonization, successful pathogens need to overcome plant basal defences. For this, (hemi)biotrophic pathogens secrete effectors that interfere with a range of physiological processes of the host plant. AvrLm4-7 is one of the cloned effectors from the hemibiotrophic fungus Leptosphaeria maculans 'brassicaceae' infecting mainly oilseed rape (Brassica napus). Although its mode of action is still unknown, AvrLm4-7 is strongly involved in L. maculans virulence. Here, we investigated the effect of AvrLm4-7 on plant defence responses in a susceptible cultivar of B. napus. Using two isogenic L. maculans isolates differing in the presence of a functional AvrLm4-7 allele [absence ('a4a7') and presence ('A4A7') of the allele], the plant hormone concentrations, defence-related gene transcription and reactive oxygen species (ROS) accumulation were analysed in infected B. napus cotyledons. Various components of the plant immune system were affected. Infection with the 'A4A7' isolate caused suppression of salicylic acid- and ethylene-dependent signalling, the pathways regulating an effective defence against L. maculans infection. Furthermore, ROS accumulation was decreased in cotyledons infected with the 'A4A7' isolate. Treatment with an antioxidant agent, ascorbic acid, increased the aggressiveness of the 'a4a7' L. maculans isolate, but not that of the 'A4A7' isolate. Together, our results suggest that the increased aggressiveness of the 'A4A7' L. maculans isolate could be caused by defects in ROS-dependent defence and/or linked to suppressed SA and ET signalling. This is the first study to provide insights into the manipulation of B. napus defence responses by an effector of L. maculans. © 2015 BSPP AND JOHN WILEY & SONS LTD.

  13. Phenological asynchrony between herbivorous insects and their hosts: signal of climate change or pre-existing adaptive strategy?

    Science.gov (United States)

    Singer, Michael C; Parmesan, Camille

    2010-10-12

    Climate change alters phenological relations between interacting species. We might expect the historical baseline, or starting-point, for such effects to be precise synchrony between the season at which a consumer most requires food and the time when its resources are most available. We synthesize evidence that synchrony was not the historical condition in two insect-plant interactions involving Edith's checkerspot butterfly (Euphydryas editha), the winter moth (Operophtera brumata) and their host plants. Initial observations of phenological mismatch in both systems were made prior to the onset of anthropogenically driven climate change. Neither species can detect the phenology of its host plants with precision. In both species, evolution of life history has involved compromise between maximizing fecundity and minimizing mortality, with the outcome being superficially maladaptive strategies in which many, or even most, individuals die of starvation through poor synchrony with their host plants. Where phenological asynchrony or mismatch with resources forms the starting point for effects of anthropogenic global warming, consumers are particularly vulnerable to impacts that exacerbate the mismatch. This vulnerability likely contributed to extinction of a well-studied metapopulation of Edith's checkerspot, and to the skewed geographical pattern of population extinctions underlying a northward and upward range shift in this species.

  14. Jasmonate-deficient plants have reduced direct and indirect defences against herbivores

    NARCIS (Netherlands)

    Thaler, J.S.; Farag, M.A.; Paré, P.W.; Dicke, M.

    2002-01-01

    Plants employ a variety of defence mechanisms, some of which act directly by having a negative effect on herbivores and others that act indirectly by attracting natural enemies of herbivores. In this study we asked if a common jasmonate-signalling pathway links the regulation of direct and indirect

  15. Cytokinins as key regulators in plant–microbe–insect interactions: connecting plant growth and defence

    NARCIS (Netherlands)

    Giron, D.; Frago, E.; Glevarec, G.; Pieterse, C.M.J.; Dicke, M.

    2013-01-01

    1. Plant hormones play important roles in regulating plant growth and defence by mediating developmental processes and signalling networks involved in plant responses to a wide range of parasitic and mutualistic biotic interactions. 2. Plants are known to rapidly respond to pathogen and herbivore

  16. Cytokinins as key regulators in plant-microbe-insect interactions: connecting plant growth and defence

    NARCIS (Netherlands)

    Giron, D.; Frago, E.; Glevarec, G.; Pieterse, C.M.J.; Dicke, M.

    2013-01-01

    Plant hormones play important roles in regulating plant growth and defence by mediating developmental processes and signalling networks involved in plant responses to a wide range of parasitic and mutualistic biotic interactions. Plants are known to rapidly respond to pathogen and herbivore attack

  17. Extracellular expression of YlLip11 with a native signal peptide from Yarrowia lipolytica MSR80 in three different yeast hosts.

    Science.gov (United States)

    Kumari, Arti; Baronian, Keith; Kunze, Gotthard; Gupta, Rani

    2015-06-01

    Lipase YlLip11 from Yarrowia lipolytica was expressed with a signal peptide encoding sequence in Arxula adeninivorans, Saccharomyces cerevisiae and Hansenula polymorpha using the Xplor®2 transformation/expression platform and an expression module with the constitutive Arxula-derived TEF1 promoter. The YlLip11 signal peptide was functional in all of the yeast hosts with 97% of the recombinant enzyme being secreted into the culture medium. However, recombinant YlLip11 with His Tag fused at C-terminal was not active. The best recombinant YlLip11 producing A. adeninivorans G1212/YRC102-YlLip11 transformant cultivated in shake flasks produced 2654 U/L lipase, followed by S. cerevisiae SEY6210/YRC103-YlLip11 (1632U/L) and H. polymorpha RB11/YRC103-YlLip11 (1144U/L). Although the biochemical parameters of YlLip11 synthesized in different hosts were similar, their glycosylation level and thermo stability differed. The protein synthesized by the H. polymorpha transformant had the highest degree of glycosylation and with a t1/2 of 60min at 70°C, exhibited the highest thermostability. Copyright © 2015 Elsevier Inc. All rights reserved.

  18. Systems biology of host-mycobiota interactions: dissecting Dectin-1 and Dectin-2 signalling in immune cells with DC-ATLAS.

    Science.gov (United States)

    Rizzetto, Lisa; De Filippo, Carlotta; Rivero, Damariz; Riccadonna, Samantha; Beltrame, Luca; Cavalieri, Duccio

    2013-11-01

    Modelling the networks sustaining the fruitful coexistence between fungi and their mammalian hosts is becoming increasingly important to control emerging fungal pathogens. The C-type lectins Dectin-1 and Dectin-2 are involved in host defense mechanisms against fungal infection driving inflammatory and adaptive immune responses and complement in containing fungal burdens. Recognizing carbohydrate structures in pathogens, their engagement induces maturation of dendritic cells (DCs) into potent immuno-stimulatory cells endowed with the capacity to efficiently prime T cells. Owing to these properties, Dectin-1 and Dectin-2 agonists are currently under investigation as promising adjuvants in vaccination procedures for the treatment of fungal infection. Thus, a detailed understanding of events' cascade specifically triggered in DCs upon engagement is of great interest in translational research. Here, we summarize the current knowledge on Dectin-1 and Dectin-2 signalling in DCs highlighting similarities and differences. Detailed maps are annotated, using the Biological Connection Markup Language (BCML) data model, and stored in DC-ATLAS, a versatile resource for the interpretation of high-throughput data generated perturbing the signalling network of DCs. Copyright © 2013 Elsevier GmbH. All rights reserved.

  19. A reverse-phase protein microarray-based screen identifies host signaling dynamics upon Burkholderia spp. infection

    Directory of Open Access Journals (Sweden)

    Chih-Yuan eChiang

    2015-07-01

    Full Text Available Burkholderia is a diverse genus of Gram-negative bacteria that cause high mortality rate in humans and cattle. The lack of effective therapeutic treatments poses serious public health threats. Insights toward host-Burkholderia spp. interaction are critical in understanding the pathogenesis of the infection as well as identifying therapeutic targets for drug development. Reverse-phase protein microarray (RPMA technology was previously proven to characterize novel biomarkers and molecular signatures associated with infectious diseases and cancers. In the present study, this technology was utilized to interrogate changes in host protein expression and post-translational phosphorylation events in macrophages infected with a collection of geographically diverse strains of Burkholderia spp. The expression or phosphorylation state of 25 proteins was altered during Burkholderia spp. infections and of which eight proteins were selected for further validation by immunoblotting. Kinetic expression patterns of phosphorylated AMPK-α1, Src, and GSK3β suggested the importance of their roles in regulating Burkholderia spp. mediated innate immune responses. Modulating inflammatory responses by perturbing AMPK-α1, Src, and GSK3β activities may provide novel therapeutic targets for future treatments.

  20. TLR2-dependent MyD88 signaling contributes to early host defense in murine Enterococcus faecium peritonitis

    NARCIS (Netherlands)

    Leendertse, Masja; Willems, Rob J. L.; Giebelen, Ida A. J.; van den Pangaart, Petra S.; Wiersinga, W. Joost; de Vos, Alex F.; Florquin, Sandrine; Bonten, Marc J. M.; van der Poll, Tom

    2008-01-01

    The incidence of infections with Enterococcus faecium is increasing worldwide. TLRs have been implicated in the recognition of pathogens and the initiation of an adequate innate immune response. We here sought to determine the roles of MyD88, the common adaptor protein involved in TLR signaling,

  1. The ethylene response factor Pti5 contributes to potato aphid resistance in tomato independent of ethylene signalling.

    Science.gov (United States)

    Wu, Chengjun; Avila, Carlos A; Goggin, Fiona L

    2015-02-01

    Ethylene response factors (ERFs) comprise a large family of transcription factors that regulate numerous biological processes including growth, development, and response to environmental stresses. Here, we report that Pti5, an ERF in tomato [Solanum lycopersicum (Linnaeus)] was transcriptionally upregulated in response to the potato aphid Macrosiphum euphorbiae (Thomas), and contributed to plant defences that limited the population growth of this phloem-feeding insect. Virus-induced gene silencing of Pti5 enhanced aphid population growth on tomato, both on an aphid-susceptible cultivar and on a near-isogenic genotype that carried the Mi-1.2 resistance (R) gene. These results indicate that Pti5 contributes to basal resistance in susceptible plants and also can synergize with other R gene-mediated defences to limit aphid survival and reproduction. Although Pti5 contains the ERF motif, induction of this gene by aphids was independent of ethylene, since the ACC deaminase (ACD) transgene, which inhibits ethylene synthesis, did not diminish the responsiveness of Pti5 to aphid infestation. Furthermore, experiments with inhibitors of ethylene synthesis revealed that Pti5 and ethylene have distinctly different roles in plant responses to aphids. Whereas Pti5 contributed to antibiotic plant defences that limited aphid survival and reproduction on both resistant (Mi-1.2+) and susceptible (Mi-1.2-) genotypes, ethylene signalling promoted aphid infestation on susceptible plants but contributed to antixenotic defences that deterred the early stages of aphid host selection on resistant plants. These findings suggest that the antixenotic defences that inhibit aphid settling and the antibiotic defences that depress fecundity and promote mortality are regulated through different signalling pathways. © The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  2. Airbus Defence & Space 4.0

    CSIR Research Space (South Africa)

    Nasr, J-M

    2017-10-01

    Full Text Available -Marc NASR – Senior Vice President Middle East & Africa 06 Oct, 2017 – Pretoria Airbus Defence & Space Airbus Defence & Space 4.0 2 “If I had asked to people what they wanted, they would have said faster horses." (Henry Ford) “Heavier...-than-air flying machines are impossible." (Lord Kelvin, President, Royal Society, 1895) Where we come from I was a child of the 80s 3 My iPhone My iPod My Google My YouTube My WhatsApp My eMail My navigation system 4 Digitalization changes...

  3. Induction of virulence factors in Giardia duodenalis independent of host attachment

    Science.gov (United States)

    Emery, Samantha J.; Mirzaei, Mehdi; Vuong, Daniel; Pascovici, Dana; Chick, Joel M.; Lacey, Ernest; Haynes, Paul A.

    2016-01-01

    Giardia duodenalis is responsible for the majority of parasitic gastroenteritis in humans worldwide. Host-parasite interaction models in vitro provide insights into disease and virulence and help us to understand pathogenesis. Using HT-29 intestinal epithelial cells (IEC) as a model we have demonstrated that initial sensitisation by host secretions reduces proclivity for trophozoite attachment, while inducing virulence factors. Host soluble factors triggered up-regulation of membrane and secreted proteins, including Tenascins, Cathepsin-B precursor, cystatin, and numerous Variant-specific Surface Proteins (VSPs). By comparison, host-cell attached trophozoites up-regulated intracellular pathways for ubiquitination, reactive oxygen species (ROS) detoxification and production of pyridoxal phosphate (PLP). We reason that these results demonstrate early pathogenesis in Giardia involves two independent host-parasite interactions. Motile trophozoites respond to soluble secreted signals, which deter attachment and induce expression of virulence factors. Trophozoites attached to host cells, in contrast, respond by up-regulating intracellular pathways involved in clearance of ROS, thus anticipating the host defence response. PMID:26867958

  4. miR-144 attenuates the host response to influenza virus by targeting the TRAF6-IRF7 signaling axis.

    Directory of Open Access Journals (Sweden)

    Carrie M Rosenberger

    2017-04-01

    Full Text Available Antiviral responses must rapidly defend against infection while minimizing inflammatory damage, but the mechanisms that regulate the magnitude of response within an infected cell are not well understood. miRNAs are small non-coding RNAs that suppress protein levels by binding target sequences on their cognate mRNA. Here, we identify miR-144 as a negative regulator of the host antiviral response. Ectopic expression of miR-144 resulted in increased replication of three RNA viruses in primary mouse lung epithelial cells: influenza virus, EMCV, and VSV. We identified the transcriptional network regulated by miR-144 and demonstrate that miR-144 post-transcriptionally suppresses TRAF6 levels. In vivo ablation of miR-144 reduced influenza virus replication in the lung and disease severity. These data suggest that miR-144 reduces the antiviral response by attenuating the TRAF6-IRF7 pathway to alter the cellular antiviral transcriptional landscape.

  5. Applying systems engineering principles towards developing defence capabilities

    CSIR Research Space (South Africa)

    Smith, CJ

    2011-09-01

    Full Text Available Due to high cost of defence systems and the advent of multi-role military platforms, defence forces can no longer replace old systems with similar newer systems, but need to effectively and continually re-evaluate their defence capability...

  6. Trends in Western Defence Planning: Regulatory, Temporal and Functional Dimensions

    DEFF Research Database (Denmark)

    Breitenbauch, Henrik Ø.

    2011-01-01

    Even as political attention/guidance has consistently moved away from core/classical defence planning areas, much less has changed than expected at the level of actual defence planning process. One might conceptually discern three major axes along which defence planning change (and the debate about...... it) is happening: Regulatory elevation; Temporal extension; Functional widening. This brief presents these axes and discusses implications....

  7. Genetics of insect resistance to plant defence

    NARCIS (Netherlands)

    Vermeer, K.M.C.A.

    2014-01-01

      Plants are chemically defended against insect herbivory in various ways. They produce a broad range of secondary metabolites that may be toxic or deterrent to insects. Specialist insects, however, are often capable of overcoming these defences. The yellow striped flea beetle (Phyllotreta

  8. Foreigners in the defence of South Africa

    African Journals Online (AJOL)

    The physical assault against the. Republic is conducted by Russian supported revolutionary and terrorist ... tertiary educational careers unhindered. How- ever, the newly-promulgated amendment to the. Defence Act ... quite a few lost their lives for the cause they believed in. Portuguese and Jewish South Africans of the July ...

  9. Swedish Defence Acquisition Transformation: A Research Agenda

    Science.gov (United States)

    2015-05-13

    of tasks and resources (personnel) • Partial merger of the DPA and the DLO Reformation of defence logistics Owns the equipment and specifies the...towards a new organisation”, • “The repair debt”, • “A strategy for the provisioning of personnel”, • “Capability in health and medical support”, and

  10. Defence Output Measures: An Economics Perspective

    Science.gov (United States)

    2011-11-01

    1 Introduction 1.1...intentionally left blank. 1 Introduction 1.1 Terms of Reference The Terms of Reference required research on defence...It also protects national interests, including independence and ‘appropriate sovereignty’ (e.g. protecting a nation’s interests in a globalised

  11. Identification of plant defence regulators through transcriptional

    Indian Academy of Sciences (India)

    Through bacterial resistance, callose deposition and pathogenesis-associated expression analyses, we identified four novel regulators of plant defence. Resistance levels in the mutants suggest that At2g19810 and [rom] At5g05790 are positive regulators, whereas At1g61370 and At3g42790 are negative regulators of plant ...

  12. Induced chemical defences in Colophospermum mopane trees ...

    African Journals Online (AJOL)

    Induced chemical defences in Colophospermum mopane trees. DCJ Wessels, C van der Waal, WF de Boer. Abstract. A field experiment was conducted in which Mopane (Colophospermum mopane) trees were subjected to three different canopy treatments:felling of trees at a mean height of 0.7m above ground level, felling ...

  13. The Immune System and Bodily Defence

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 2; Issue 2. The Immune System and Bodily Defence How Do Parasites and the Immune System Choose their Dances? Vineeta Bal Satyajit Rath. Series Article Volume 2 Issue 2 February 1997 pp 17-24 ...

  14. The Cooperative Ballistic Missile Defence Game

    NARCIS (Netherlands)

    Evers, L.; Barros, A.I.; Monsuur, H.

    2013-01-01

    The increasing proliferation of ballistic missiles and weapons of mass destruction poses new risks worldwide. For a threatened nation and given the characteristics of this threat a layered ballistic missile defence system strategy appears to be the preferred solution. However, such a strategy

  15. The Immune System and Bodily Defence

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 2; Issue 6. The Immune System and Bodily Defence How Does the Immune System Organize Itself so as to Connect Target Recognition to Expected Functions? Vineeta Bal Satyajit Rath. Series Article Volume 2 Issue 6 June 1997 pp 25-38 ...

  16. Closing the loop: towards strategic defence management

    NARCIS (Netherlands)

    de Spiegeleire, S.; van Hooft, P.; Culpepper, C.; Willems, R.

    2009-01-01

    How do defence-organisations (or organisations with comparable profiles) of other countries map out policy goals and how are policy goals related to activities and capabilities and the required financial means, and finally how does the feedback loop on the performance in all these areas take place?

  17. Reliability analysis of flood defence systems

    NARCIS (Netherlands)

    Steenbergen, H.M.G.M.; Lassing, B.L.; Vrouwenvelder, A.C.W.M.; Waarts, P.H.

    2004-01-01

    In recent years an advanced program for the reliability analysis of flood defence systems has been under development. This paper describes the global data requirements for the application and the setup of the models. The analysis generates the probability of system failure and the contribution of

  18. South Africa's Defence Industrial Participation in Perspective

    African Journals Online (AJOL)

    jvdyk

    2014-03-31

    Mar 31, 2014 ... One is the DIP, managed exclusively by Armscor, South Africa's acquisition agency. DIP favours pursuing ..... and NIP (the DTI) custodians. DIP directly caused a substantial number of mergers between prominent .... “Defence acquisitions – Unpacking the package deals”. ISS occasional paper no. 29.

  19. Psychobiology of coping and defence strategies

    NARCIS (Netherlands)

    Ursin, H.; Olff, M.

    1993-01-01

    The stress response should be regarded as an alarm system, occurring whenever there is something missing. Lack of information (uncertainty), and the absence or loss of control produce alarm, presence of information and control (coping), or cognitive defence mechanisms (distorted stimulus

  20. Signatures of ESR signals and TL observed in quartz of Kizu river sediments and in host rocks

    Science.gov (United States)

    Nosohara, Y.; Toyoda, S.; Takada, M.; Shimada, A.; Masanori, Y.

    2013-12-01

    Paramagnetic lattice defects in quartz have recently been used as tracers to study the transportation of sediments on the surface of the earth especially for the origin of aeolian dust (e.g. Toyoda and Naruse, 2002), as isotopes have been used. Studies on aeolian dust have used only the E1' center while impurity centers were shown to be other useful signatures in the studies of river sediments (Shimada, 2008). Then the ESR signals of the E1' center in quartz was used to investigate the origin of the loess in MIS 1 and 2 (Toyoda and Naruse, 2002) and these diments in the Sea of Japan (Nagashima et al., 2007), Shimada (2008) showed that TLCI (thermiluminescence color image) may be useful for similar qualitative study on river sediments. In the present study, the wavelength-temperature two demensional thermoluminescence measurement was employed, together with the ESR measurements, to investigate the origin of the river sediments quantitatively. We collected 36 river sediments and 5 granites which are possible sources of the river sediments. The samples were crushed and sieved to 1000-500, 500-250, and 250-75 micrometers. Quartz grains were extracted from each size fraction by chemical treatment and density separation. The quartz grains were heated at 400°C for 1 h to erase the inherited ESR signals before gamma ray irradiation. ESR measurements were performed at room temperature and at 81 K to observe E1' and Ge, and Al and Ti centers, respectively. The impurity centers were enhanced by gamma ray irradiation. The formation efficiencies of the signals at the origin were obtained, which probably correspond to impurity concentrations in quartz. The E1' center was observed after heating the sample irradiated to 2.5kGy at 300°C for 15 min. The formation efficiencies of impurity centers and the intensity of the E1' center showed constant values in 10 samples of sediments of Muro river with standard deviations of (7-12%). It was also found that these values characterize

  1. Endothelial Cell Apoptosis Induces TGF-β Signaling-Dependent Host Endothelial-Mesenchymal Transition to Promote Transplant Arteriosclerosis.

    Science.gov (United States)

    Li, J; Xiong, J; Yang, B; Zhou, Q; Wu, Y; Luo, H; Zhou, H; Liu, N; Li, Y; Song, Z; Zheng, Q

    2015-12-01

    Endothelial cells (ECs) apoptosis is an initial event in transplant arteriosclerosis (TA), resulting in allograft function loss. To elucidate the precise mechanisms of ECs apoptosis leading to neointimal smooth muscle cells (SMCs) accumulation during TA. We induced apoptosis in cultured ECs by overexpressing p53 through lentivirus-mediated transfection. ECs apoptosis induced the production of transforming growth factor (TGF)-β1 in both apoptotic and neighboring viable cells, leading to increased TGF-β1 in the culture media. Conditioned media from Ltv-p53-transfected ECs further promoted transition of cultured ECs to SM-like cells by activating TGF-β/Smad3, PI3K/Akt/mTOR, and MAPK/ERK signaling in a TGF-β-dependent manner. In transgenic rat aorta transplantation models, inhibition of ECs apoptosis in Bcl-xL(+/+) knock-in rat aortic allografts significantly reduced TGF-β1 production both in allograft endothelia and in blood plasma, which in turn decreased accumulation of SM22α+ cells from transgenic recipient ECs originally marked with EGFP knock-in in neointima and alleviated TA. Systemic treatment with SIS3, AP23573, or PD98059 also prevented recipient ECs-originated SM-like cells accumulation and intima hyperplasia in aortic allografts. These data suggest that allograft EC apoptosis induced recipient endothelial-mesenchymal (smooth muscle) transition via TGF-β signaling, resulting in recipient EC-derived SMC accumulation as a major mechanism of vascular remodeling during TA. © Copyright 2015 The American Society of Transplantation and the American Society of Transplant Surgeons.

  2. Coping and defence mechanisms: what's the difference?--second act.

    Science.gov (United States)

    Kramer, Ueli

    2010-06-01

    Research into adaptational processes has sometimes been confusing as regards differentiating coping and defence mechanisms. This theoretical discussion is based on Cramer's effort to disentangle the two concepts concerning the psychological processes involved, as well as acknowledge their mutual overlapping. Although such an effort is needed, at the same time several issues should be re-addressed and further implications on the differentiation of coping and defence processes discussed, such as consciousness and intentionality, functionality, adaptiveness, and the question of trait versus state. Based on Cramer's review, a search was conducted for current models on defence and coping that address the aforementioned implications. Only theoretical models that differentiate the defence and coping concepts, without necessarily presenting related empirical evidence, were taken into account. Recent integrative models of defence and coping yield a more differentiated picture with regard to these issues: coping includes conscious and unconscious efforts, coping and defence serve very similar functions, adaptiveness can be defined in qualitative (defences) and quantitative (coping) terms and the question of stability of defences and coping needs to be more fully explored empirically. Furthermore, the nature of the underlying fear can be theoretically differentiated and related to the difference between coping and defence. Also, the implication of competence-related aspects of functioning (coping) and of internal determinants of functioning (defence) is discussed. Implications for research perspectives implying defence and coping concepts based on observer-rating methodology are proposed.

  3. Functional genomics identifies type I interferon pathway as central for host defense against Candida albicans

    NARCIS (Netherlands)

    Smeekens, Sanne P.; Ng, Aylwin; Kumar, Vinod; Johnson, Melissa D.; Plantinga, Theo S.; van Diemen, Cleo; Arts, Peer; Verwiel, Eugene T. P.; Gresnigt, Mark S.; Fransen, Karin; van Sommeren, Suzanne; Oosting, Marije; Cheng, Shih-Chin; Joosten, Leo A. B.; Hoischen, Alexander; Kullberg, Bart-Jan; Scott, William K.; Perfect, John R.; van der Meer, Jos W. M.; Wijmenga, Cisca; Netea, Mihai G.; Xavier, Ramnik J.

    Candida albicans is the most common human fungal pathogen causing mucosal and systemic infections. However, human antifungal immunity remains poorly defined. Here by integrating transcriptional analysis and functional genomics, we identified Candida-specific host defence mechanisms in humans.

  4. The European Security and Defence Policy

    DEFF Research Database (Denmark)

    Adler-Nissen, Rebecca

    2009-01-01

    The European Security and Defence Policy (ESDP), which is the operational military and civilian dimension of the Common Foreign and Security Policy (CFSP), is today one of the most dynamic areas of the European Union. However, it is only recently that the EU has acquired explicit military decision....... The Union is thus gradually emerging as an important player on the international scene, with a strategic vision, as well as diplomatic, civilian and military crisis-management instruments that complement the existing economic, commercial, humanitarian and development policies on which the EU has hitherto...... built its reputation as a ‘soft power'. Despite its rapid development, many still regard the EU as weak and ineffi cient when it comes to security and defence policy. Moreover, the EU struggles with internal divisions and has a strained relationship with NATO. Nonetheless, there are good reasons...

  5. Transformational Leadership in the Estonian Defence Forces

    OpenAIRE

    Antek Kasemaa

    2015-01-01

    Purpose – The study is a contribution to the validation of the 15 items and 5 subscales Transformational Leadership Scale (TLS) proposed by Rafferty and Griffin (2004). Design/methodology/approach – The sample includes participants from different levels of the Estonian Defence Forces (EDF) military hierarchy (N=2570). The structure of the TLS was examined by using exploratory and confirmatory factor analyses. Additionally ANOVA was used to compare the results between different subsamples....

  6. Applied Cyberpsychology: Military and Defence Applications

    OpenAIRE

    Dando, C.J.; Tranter, C

    2016-01-01

    Virtual environments are synthetic computer simulations that represent activities at a high degree of realism. Virtual environments have numerous applications for military and defence purposes, ranging from allowing personnel to experience realistic, high-pressure situations with a sense of presence, but in the absence of real world risk, to modelling threats to national and international infrastructure to improve resilience. Emerging opportunities also exist for communication and intelligenc...

  7. Swedish Defence Acquisition Transformation - A Research Agenda

    Science.gov (United States)

    2015-04-30

    any other provision of law , no person shall be subject to a penalty for failing to comply with a collection of information if it does not display a...reductions in defence expenditure (the peace dividend); participation in Peace Support Operations (PSOs); Lessons Learned (LL) from these operations...especially in the area of logistics; revolutionary development in the area of Information and Communication Technology ( ICT ); emergence of novel

  8. Doubts about a classic defence of abortion.

    Science.gov (United States)

    Difford, Jo

    2011-01-01

    Professor Judith Jarvis Thomson's seminal paper "A defence of abortion" published in 1971 has formed part of higher education syllabi for decades. In the paper Thomson criticizes one of the fundamental arguments against abortion, that is, the right of the foetus to life by denying that the foetus is a person. This article argues that her thought experiments do not compare to the reality of abortion and focuses on the influence of the paper on arguments concerning personhood.

  9. Escherichia coli cyclomodulin Cif induces G2 arrest of the host cell cycle without activation of the DNA-damage checkpoint-signalling pathway.

    Science.gov (United States)

    Taieb, Frédéric; Nougayrède, Jean-Philippe; Watrin, Claude; Samba-Louaka, Ascel; Oswald, Eric

    2006-12-01

    The cycle inhibiting factor (Cif) belongs to a family of bacterial toxins and effector proteins, the cyclomodulins, that deregulate the host cell cycle. Upon injection into HeLa cells by the enteropathogenic Escherichia coli (EPEC) type III secretion system, Cif induces a cytopathic effect characterized by the recruitment of focal adhesion plates and the formation of stress fibres, an irreversible cell cycle arrest at the G(2)/M transition, and sustained inhibitory phosphorylation of mitosis inducer, CDK1. Here, we report that the reference typical EPEC strain B171 produces a functional Cif and that lipid-mediated delivery of purified Cif into HeLa cells induces cell cycle arrest and actin stress fibres, implying that Cif is necessary and sufficient for these effects. EPEC infection of intestinal epithelial cells (Caco-2, IEC-6) also induces cell cycle arrest and CDK1 inhibition. The effect of Cif is strikingly similar to that of cytolethal distending toxin (CDT), which inhibits the G(2)/M transition by activating the DNA-damage checkpoint pathway. However, in contrast to CDT, Cif does not cause phosphorylation of histone H2AX, which is associated with DNA double-stranded breaks. Following EPEC infection, the checkpoint effectors ATM/ATR, Chk1 and Chk2 are not activated, the levels of the CDK-activating phosphatases Cdc25B and Cdc25C are not affected, and Cdc25C is not sequestered in host cell cytoplasm. Hence, Cif activates a DNA damage-independent signalling pathway that leads to inhibition of the G(2)/M transition.

  10. The Toxoplasma Parasitophorous Vacuole: An Evolving Host-Parasite Frontier.

    Science.gov (United States)

    Clough, Barbara; Frickel, Eva-Maria

    2017-06-01

    The parasitophorous vacuole is a unique replicative niche for apicomplexan parasites, including Toxoplasma gondii. Derived from host plasma membrane, the vacuole is rendered nonfusogenic with the host endolysosomal system. Toxoplasma secretes numerous proteins to modify the forming vacuole, enable nutrient uptake, and set up mechanisms of host subversion. Here we describe the pathways of host-parasite interaction at the parasitophorous vacuole employed by Toxoplasma and host, leading to the intricate balance of host defence versus parasite survival. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Identification of bovine leukemia virus tax function associated with host cell transcription, signaling, stress response and immune response pathway by microarray-based gene expression analysis

    Directory of Open Access Journals (Sweden)

    Arainga Mariluz

    2012-03-01

    Full Text Available Abstract Background Bovine leukemia virus (BLV is associated with enzootic bovine leukosis and is closely related to human T-cell leukemia virus type I. The Tax protein of BLV is a transcriptional activator of viral replication and a key contributor to oncogenic potential. We previously identified interesting mutant forms of Tax with elevated (TaxD247G or reduced (TaxS240P transactivation effects on BLV replication and propagation. However, the effects of these mutations on functions other than transcriptional activation are unknown. In this study, to identify genes that play a role in the cascade of signal events regulated by wild-type and mutant Tax proteins, we used a large-scale host cell gene-profiling approach. Results Using a microarray containing approximately 18,400 human mRNA transcripts, we found several alterations after the expression of Tax proteins in genes involved in many cellular functions such as transcription, signal transduction, cell growth, apoptosis, stress response, and immune response, indicating that Tax protein has multiple biological effects on various cellular environments. We also found that TaxD247G strongly regulated more genes involved in transcription, signal transduction, and cell growth functions, contrary to TaxS240P, which regulated fewer genes. In addition, the expression of genes related to stress response significantly increased in the presence of TaxS240P as compared to wild-type Tax and TaxD247G. By contrast, the largest group of downregulated genes was related to immune response, and the majority of these genes belonged to the interferon family. However, no significant difference in the expression level of downregulated genes was observed among the Tax proteins. Finally, the expression of important cellular factors obtained from the human microarray results were validated at the RNA and protein levels by real-time quantitative reverse transcription-polymerase chain reaction and western blotting

  12. Coping and defence mechanisms: What are we assessing?

    Science.gov (United States)

    Maricutoiu, Laurentiu P; Crasovan, Danut I

    2016-04-01

    The present research study addresses the disparity between theoretical considerations and empirical evidence regarding the relationships between coping strategies and defence mechanisms. Self-reported measures of coping and defences were administered to a Romanian adult sample (N = 542; 74.53% female, mean age = 31.28). Using structural equation modelling, models that assumed independence between coping and defences were compared with models that assumed the existence of relationships between the two concepts. Findings identified strong relationships between coping and defences, indicating large common variance between the two concepts. Furthermore, results suggested that coping and defences can be classified into two independent types of adaptation processes. Results of this research study suggested that coping and defences are facets of common adaptation processes. © 2014 International Union of Psychological Science.

  13. Communication between host organism and cancer cells is transduced by systemic sphingosine kinase 1/sphingosine 1-phosphate signalling to regulate tumour metastasis

    Science.gov (United States)

    Ponnusamy, Suriyan; Selvam, Shanmugam Panneer; Mehrotra, Shikhar; Kawamori, Toshihiko; Snider, Ashley J; Obeid, Lina M; Shao, Yuan; Sabbadini, Roger; Ogretmen, Besim

    2012-01-01

    Mechanisms by which cancer cells communicate with the host organism to regulate lung colonization/metastasis are unclear. We show that this communication occurs via sphingosine 1-phosphate (S1P) generated systemically by sphingosine kinase 1 (SK1), rather than via tumour-derived S1P. Modulation of systemic, but not tumour SK1, prevented S1P elevation, and inhibited TRAMP-induced prostate cancer growth in TRAMP+/+SK1−/− mice, or lung metastasis of multiple cancer cells in SK1−/− animals. Genetic loss of SK1 activated a master metastasis suppressor, Brms1 (breast carcinoma metastasis suppressor 1), via modulation of S1P receptor 2 (S1PR2) in cancer cells. Alterations of S1PR2 using pharmacologic and genetic tools enhanced Brms1. Moreover, Brms1 in S1PR2−/− MEFs was modulated by serum S1P alterations. Accordingly, ectopic Brms1 in MB49 bladder cancer cells suppressed lung metastasis, and stable knockdown of Brms1 prevented this process. Importantly, inhibition of systemic S1P signalling using a novel anti-S1P monoclonal antibody (mAb), Sphingomab, attenuated lung metastasis, which was prevented by Brms1 knockdown in MB49 cells. Thus, these data suggest that systemic SK1/S1P regulates metastatic potential via regulation of tumour S1PR2/Brms1 axis. PMID:22707406

  14. Non-immunological defence mechanisms of the gut.

    OpenAIRE

    Sarker, S. A.; Gyr, K

    1992-01-01

    Non-immunological defence mechanisms represent an important line of intestinal defence in addition to humoral and cellular immunity. This review summarises the evidence for the role of the non-immunological defence system. Protective factors that have been amply documented are gastric juice, intestinal motility, and intestinal flora. Components of pancreatic juice, lysozyme, and epithelial cell turnover may also be involved. Special attention is given to gastric acid, infection with Helicobac...

  15. Defence behaviour of reindeer in response to flying parasitic Diptera

    OpenAIRE

    Karter, Andrew J.; Ivar Folstad

    1989-01-01

    Similar defence behaviours were exhibited by a reindeer when experimentally exposed to three different species of tethered, flying parasitic Diptera, Cephenemyia trompe (Modeer), Hypoderma tarandi (L) and Tabanid. Defencive behavioural responses appeared to be related to attack angle, and were not elicited by auditory stimuli. These observations raise questions about the validity of parasite species-specific defence responses in reindeer.Forsvars-adferd hos rein angrepet av flyvende, parasitt...

  16. To each its own: differential response of specialist and generalist herbivores to plant defence in willows.

    Science.gov (United States)

    Volf, Martin; Hrcek, Jan; Julkunen-Tiitto, Riitta; Novotny, Vojtech

    2015-07-01

    Plant-insect food webs tend to be dominated by interactions resulting from diffuse co-evolution between plants and multiple lineages of herbivores rather than by reciprocal co-evolution and co-cladogenesis. Plants therefore require defence strategies effective against a broad range of herbivore species. In one extreme, plants could develop a single universal defence effective against all herbivorous insects, or tailor-made strategies for each herbivore species. The evolution and ecology of plant defence has to be studied with entire insect assemblages, rather than small subsets of pairwise interactions. The present study examines whether specialists and generalists in three coexisting insect lineages, forming the leaf-chewing guild, respond uniformly to plant phylogeny, secondary metabolites, nutrient content and mechanical antiherbivore defences of their hosts, thus permitting universal plant defence strategies against specialized and generalist folivorous insects from various taxa. The extensive data on folivorous assemblages comprising three insect orders and 193 species are linked with plant phylogeny, secondary chemistry (salicylates, flavonoids and tannins), leaf morphological traits [specific leaf area (SLA) and trichome coverage], nutrient (C : N) content and growth form of eight willow (Salix) and one aspen (Populus) species growing in sympatry. Generalists responded to overall host plant chemistry and trichomes, whilst specialists responded to host plant phylogeny and secondary metabolites that are unique to willows and that are capable of being utilized as an antipredator protection. We did not find any significant impact of other plant traits, that is SLA, C : N ratio, flavonoids, tannins and growth form, on the composition of leaf-chewing communities. Our results show that the response to plant traits is differential among specialists and generalists. This finding constrains the ability of plants to develop defensive traits universally effective

  17. Networks and network analysis for defence and security

    CERN Document Server

    Masys, Anthony J

    2014-01-01

    Networks and Network Analysis for Defence and Security discusses relevant theoretical frameworks and applications of network analysis in support of the defence and security domains. This book details real world applications of network analysis to support defence and security. Shocks to regional, national and global systems stemming from natural hazards, acts of armed violence, terrorism and serious and organized crime have significant defence and security implications. Today, nations face an uncertain and complex security landscape in which threats impact/target the physical, social, economic

  18. Cyclic lipopeptides from Bacillus subtilis activate distinct patterns of defence responses in grapevine.

    Science.gov (United States)

    Farace, Giovanni; Fernandez, Olivier; Jacquens, Lucile; Coutte, François; Krier, François; Jacques, Philippe; Clément, Christophe; Barka, Essaid Ait; Jacquard, Cédric; Dorey, Stéphan

    2015-02-01

    Non-self-recognition of microorganisms partly relies on the perception of microbe-associated molecular patterns (MAMPs) and leads to the activation of an innate immune response. Bacillus subtilis produces three main families of cyclic lipopeptides (LPs), namely surfactins, iturins and fengycins. Although LPs are involved in induced systemic resistance (ISR) activation, little is known about defence responses induced by these molecules and their involvement in local resistance to fungi. Here, we showed that purified surfactin, mycosubtilin (iturin family) and plipastatin (fengycin family) are perceived by grapevine plant cells. Although surfactin and mycosubtilin stimulated grapevine innate immune responses, they differentially activated early signalling pathways and defence gene expression. By contrast, plipastatin perception by grapevine cells only resulted in early signalling activation. Gene expression analysis suggested that mycosubtilin activated salicylic acid (SA) and jasmonic acid (JA) signalling pathways, whereas surfactin mainly induced an SA-regulated response. Although mycosubtilin and plipastatin displayed direct antifungal activity, only surfactin and mycosubtilin treatments resulted in a local long-lasting enhanced tolerance to the necrotrophic fungus Botrytis cinerea in grapevine leaves. Moreover, challenge with specific strains overproducing surfactin and mycosubtilin led to a slightly enhanced stimulation of the defence response compared with the LP-non-producing strain of B. subtilis. Altogether, our results provide the first comprehensive view of the involvement of LPs from B. subtilis in grapevine plant defence and local resistance against the necrotrophic pathogen Bo. cinerea. Moreover, this work is the first to highlight the ability of mycosubtilin to trigger an immune response in plants. © 2014 BSPP AND JOHN WILEY & SONS LTD.

  19. The Transformation from Defence Procurement to Defence Acquisition - Opportunities for New Forms of Analytical Support

    Science.gov (United States)

    2010-04-01

    internationalisation of industry, this is definitely no longer the case. All things considered, it is probably fair to say that Sweden, from a military...consequent budgetary reductions, as well as changes in legislation and the internationalisation of the defence industry, have forced the Swedish AF and FMV to

  20. Invertebrates as animal models for Staphylococcus aureus pathogenesis: a window into host-pathogen interaction.

    Science.gov (United States)

    García-Lara, Jorge; Needham, Andrew J; Foster, Simon J

    2005-03-01

    Recently, the use of invertebrate models of infection has given exciting insights into host-pathogen interaction for a number of bacteria. In particular, this has revealed important factors of the host response with remarkable parallels in higher organisms. Here, we review the advances attained in the elucidation of virulence determinants of a major human pathogen, Staphylococcus aureus, in relation to the invertebrate models thus far applied, the silkworm (Bombyx mori), the fruit fly (Drosophila melanogaster) and the roundworm (Caenorhabditis elegans). Also, the major pathways of host defence are covered in light of the response to S. aureus and the similarities and divergences in innate immunity of vertebrates and invertebrates. Consequently, we comparatively consider pathogen recognition receptors, signal transduction pathways (including Toll, Imd and others), and the humoral and cellular antimicrobial effectors. The technically convenient and ethically acceptable invertebrates appear as a valuable first tool to discriminate molecules participating from both sides of the host-S. aureus interaction as well as a high throughput method for antimicrobial screening.

  1. Oxidative and nitrosative stress defences of Helicobacter and Campylobacter species that counteract mammalian immunity.

    Science.gov (United States)

    Flint, Annika; Stintzi, Alain; Saraiva, Lígia M

    2016-11-01

    Helicobacter and Campylobacter species are Gram-negative microaerophilic host-associated heterotrophic bacteria that invade the digestive tract of humans and animals. Campylobacter jejuni is the major worldwide cause of foodborne gastroenteritis in humans, while Helicobacter pylori is ubiquitous in over half of the world's population causing gastric and duodenal ulcers. The colonisation of the gastrointestinal system by Helicobacter and Campylobacter relies on numerous cellular defences to sense the host environment and respond to adverse conditions, including those imposed by the host immunity. An important antimicrobial tool of the mammalian innate immune system is the generation of harmful oxidative and nitrosative stresses to which pathogens are exposed during phagocytosis. This review summarises the regulators, detoxifying enzymes and subversion mechanisms of Helicobacter and Campylobacter that ultimately promote the successful infection of humans.

  2. Peer-to-Peer Enclaves for Improving Network Defence

    Directory of Open Access Journals (Sweden)

    David W. Archer

    2013-07-01

    Full Text Available Information about cyberthreats within networks spreads slowly relative to the speed at which those threats spread. Typical "threat feeds" that are commercially available also disseminate information slowly relative to the propagation speed of attacks, and they often convey irrelevant information about imminent threats. As a result, hosts sharing a network may miss opportunities to improve their defence postures against imminent attack because needed information arrives too late or is lost in irrelevant noise. We envision timely, relevant peer-to-peer sharing of threat information – based on current technologies – as a solution to these problems and as a useful design pattern for defensive cyberwarfare. In our setting, network nodes form communities that we call enclaves, where each node defends itself while sharing information on imminent threats with peers that have similar threat exposure. In this article, we present our vision for this solution. We sketch the architecture of a typical node in such a network and how it might interact with a framework for sharing threat information; we explain why certain defensive countermeasures may work better in our setting; we discuss current tools that could be used as components in our vision; and we describe opportunities for future research and development.

  3. Alcohol misuse in patients attending a defence force general ...

    African Journals Online (AJOL)

    Alcohol misuse in patients attending a defence force general medical clinic. D Bekker, DP Van Velden. Abstract. Aim: To determine the prevalence of alcohol misuse in adult patients attending a defence force general practice clinic. Design: Descriptive cross-sectional survey. Methods: The setting is a military sickbay ...

  4. Methodology to detect gaps in a soccer defence

    DEFF Research Database (Denmark)

    Knudsen, Nikolas Sten; Andersen, Thomas Bull

    2015-01-01

    The purpose of the present study was to create a methodology which can provide information about gaps in an opposing team’s defence. To illustrate the methodology, a defence was tracked during a game in the danish Superliga using ZXY radio tracking and analysed using the methodology. Results showed...

  5. Improvement of program-goal method in defence planning system

    Directory of Open Access Journals (Sweden)

    Р.М. Федоренко

    2005-01-01

    Full Text Available  The article proposes the conception of defence planning system development with program-goal method application that based on analysis of advanced experience of developed countries. Article specified the place of program-goal method in resolving defence planning tasks of national security.

  6. Options for Enhancing Nordic–Baltic Defence and Security Cooperation

    DEFF Research Database (Denmark)

    Breitenbauch, Henrik Ø.; Kristensen, Kristian Søby; Schaub Jr, Gary John

    is challenged to respond, particularly in the areas of defence and security. This report begins with the regional demand for enhanced defence and security cooperation. This was the background for a workshop that was held at the Centre for Military Studies in March 2017 consisting of 25 regional experts, all...

  7. Pareto Efficient Solution of Attack-Defence Trees

    NARCIS (Netherlands)

    Aslanyan, Zaruhi; Nielson, Flemming

    Attack-defence trees are a promising approach for representing threat scenarios and possible countermeasures in a concise and intuitive manner. An attack-defence tree describes the interaction between an attacker and a defender, and is evaluated by assigning parameters to the nodes, such as

  8. From Defence to Development : Redirecting Military Resources in ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    From Defence to Development : Redirecting Military Resources in South Africa. Couverture du livre From Defence to Development : Redirecting Military Resources in South Africa. Directeur(s) : Jacklyn Cock et Penny Mckenzie. Maison(s) d'édition : David Philip, CRDI. 1 janvier 1998. ISBN : Épuisé. 234 pages. e-ISBN :.

  9. Metabolic Engineering of Chemical Defence Pathways in Plant Disease Control

    DEFF Research Database (Denmark)

    Rook, Frederik

    2016-01-01

    Plants produce a wide variety of specialized (or secondary) metabolites that function as chemical defence compounds and provide protection against microbial pathogens or herbivores. This chapter focuses on the metabolic engineering of biosynthetic pathways for plant chemical defence compounds...... with antimicrobial properties for use in crop protection. It presents an overview of the metabolic engineering efforts made in the area of plant chemical defence. For in-depth information on the characteristics of a specific class of chemical defence compounds, the reader is referred to the specialized reviews...... on each topic. The chapter reviews the some of the scientific and technical challenges in metabolic engineering and the new possibilities emerging from recent technological developments. It concludes by discussing the outlook for bioengineered chemical defences as part of crop protection strategies, also...

  10. Fusion genetic analysis of jasmonate-signalling mutants in Arabidopsis

    DEFF Research Database (Denmark)

    Jensen, Anders Bøgh; Raventos, D.; Mundy, John Williams

    2002-01-01

    Jasmonates induce plant-defence responses and act to regulate defence-related genes including positive feedback of the lipoxygenase 2 (LOX2) gene involved in jasmonate synthesis. To identify jasmonate-signalling mutants, we used a fusion genetic strategy in which the firefly luciferase (FLUC...

  11. Raise your defence: a baseline for security

    CERN Multimedia

    Computer Security Team

    2011-01-01

    It is an unfair imbalance: the (computer) security of a system/service is only as strong as the weakest link in the chain of protection. This provides attackers with an incredible advantage: they can choose when to attack, where and with which means. The defence side is permanently under pressure: they must defend at all times all assets against all eventualities. For computer security, this means that every computer system, every account, every web site and every service must be properly protected --- always.   In particular, at CERN, those services visible to the Internet are permanently probed. Web sites and servers are permanently scanned by adversaries for vulnerabilities; attackers repeatedly try to guess user passwords on our remote access gateways like LXPLUS or CERNTS; computing services, e.g. for Grid computing, are analysed again and again by malicious attackers for weaknesses which can be exploited. Thanks to the vigilance of the corresponding system and service experts, these atta...

  12. Effects of Staphylococcus aureus-hemolysin A on calcium signalling in immortalized human airway epithelial cells.

    Science.gov (United States)

    Eichstaedt, Stefanie; Gäbler, Karoline; Below, Sabine; Müller, Christian; Kohler, Christian; Engelmann, Susanne; Hildebrandt, Petra; Völker, Uwe; Hecker, Michael; Hildebrandt, Jan-Peter

    2009-02-01

    Part of the innate defence of bronchial epithelia against bacterial colonization is secretion of salt and water which generally depends on coordinated actions of receptor-mediated cAMP- and calcium signalling. The hypothesis that Staphylococcus aureus-virulence factors interfere with endogenous signals in host cells was tested by measuring agonist-mediated changes in [Ca(2+)](i) in S9 cells upon pre-incubation with bacterial secretory products. S9 cells responded to mAChR-activation with calcium release from intracellular stores and capacitative calcium influx. Treatment of cells with culture supernatants of S. aureus (COL) or with recombinant alpha-hemolysin (Hla) resulted in time- and concentration-dependent changes in [Ca(2+)](i). High concentrations of Hla (2000 ng/ml) resulted in elevations in [Ca(2+)](i) elicited by accelerated calcium influx. A general Hla-mediated permeabilization of S9 cell membranes to small molecules, however, did not occur. Lower concentrations of Hla (200 ng/ml) induced a reduction in [Ca(2+)](i)-levels during the sustained plateau phase of receptor-mediated calcium signalling which was abolished by pre-incubation of cells with carboxyeosin, an inhibitor of the plasma membrane calcium-ATPase. This indicates that low concentrations of Hla change calcium signalling by accelerating pump-driven extrusion of Ca(2+) ions. In vivo, such a mechanism may result in attenuation of calcium-mediated cellular defence functions and facilitation of bacterial adherence to the bronchial epithelium.

  13. Specificity in Mesograzer-Induced Defences in Seagrasses.

    Directory of Open Access Journals (Sweden)

    Begoña Martínez-Crego

    Full Text Available Grazing-induced plant defences that reduce palatability to herbivores are widespread in terrestrial plants and seaweeds, but they have not yet been reported in seagrasses. We investigated the ability of two seagrass species to induce defences in response to direct grazing by three associated mesograzers. Specifically, we conducted feeding-assayed induction experiments to examine how mesograzer-specific grazing impact affects seagrass induction of defences within the context of the optimal defence theory. We found that the amphipod Gammarus insensibilis and the isopod Idotea chelipes exerted a low-intensity grazing on older blades of the seagrass Cymodocea nodosa, which reflects a weak grazing impact that may explain the lack of inducible defences. The isopod Synischia hectica exerted the strongest grazing impact on C. nodosa via high-intensity feeding on young blades with a higher fitness value. This isopod grazing induced defences in C. nodosa as indicated by a consistently lower consumption of blades previously grazed for 5, 12 and 16 days. The lower consumption was maintained when offered tissues with no plant structure (agar-reconstituted food, but showing a reduced size of the previous grazing effect. This indicates that structural traits act in combination with chemical traits to reduce seagrass palatability to the isopod. Increase in total phenolics but not in C:N ratio and total nitrogen of grazed C. nodosa suggests chemical defences rather than a modified nutritional quality as primarily induced chemical traits. We detected no induction of defences in Zostera noltei, which showed the ability to replace moderate losses of young biomass to mesograzers via compensatory growth. Our study provides the first experimental evidence of induction of defences against meso-herbivory that reduce further consumption in seagrasses. It also emphasizes the relevance of grazer identity in determining the level of grazing impact triggering resistance and

  14. Specificity in Mesograzer-Induced Defences in Seagrasses.

    Science.gov (United States)

    Martínez-Crego, Begoña; Arteaga, Pedro; Ueber, Alexandra; Engelen, Aschwin H; Santos, Rui; Molis, Markus

    2015-01-01

    Grazing-induced plant defences that reduce palatability to herbivores are widespread in terrestrial plants and seaweeds, but they have not yet been reported in seagrasses. We investigated the ability of two seagrass species to induce defences in response to direct grazing by three associated mesograzers. Specifically, we conducted feeding-assayed induction experiments to examine how mesograzer-specific grazing impact affects seagrass induction of defences within the context of the optimal defence theory. We found that the amphipod Gammarus insensibilis and the isopod Idotea chelipes exerted a low-intensity grazing on older blades of the seagrass Cymodocea nodosa, which reflects a weak grazing impact that may explain the lack of inducible defences. The isopod Synischia hectica exerted the strongest grazing impact on C. nodosa via high-intensity feeding on young blades with a higher fitness value. This isopod grazing induced defences in C. nodosa as indicated by a consistently lower consumption of blades previously grazed for 5, 12 and 16 days. The lower consumption was maintained when offered tissues with no plant structure (agar-reconstituted food), but showing a reduced size of the previous grazing effect. This indicates that structural traits act in combination with chemical traits to reduce seagrass palatability to the isopod. Increase in total phenolics but not in C:N ratio and total nitrogen of grazed C. nodosa suggests chemical defences rather than a modified nutritional quality as primarily induced chemical traits. We detected no induction of defences in Zostera noltei, which showed the ability to replace moderate losses of young biomass to mesograzers via compensatory growth. Our study provides the first experimental evidence of induction of defences against meso-herbivory that reduce further consumption in seagrasses. It also emphasizes the relevance of grazer identity in determining the level of grazing impact triggering resistance and compensatory

  15. Evolution of pyrrolizidine alkaloid biosynthesis in Apocynaceae: revisiting the defence de-escalation hypothesis.

    Science.gov (United States)

    Livshultz, Tatyana; Kaltenegger, Elisabeth; Straub, Shannon C K; Weitemier, Kevin; Hirsch, Elliot; Koval, Khrystyna; Mema, Lumi; Liston, Aaron

    2018-02-26

    Plants produce specialized metabolites for their defence. However, specialist herbivores adapt to these compounds and use them for their own benefit. Plants attacked predominantly by specialists may be under selection to reduce or eliminate production of co-opted chemicals: the defence de-escalation hypothesis. We studied the evolution of pyrrolizidine alkaloids (PAs) in Apocynaceae, larval host plants for PA-adapted butterflies (Danainae, milkweed and clearwing butterflies), to test if the evolutionary pattern is consistent with de-escalation. We used the first PA biosynthesis specific enzyme (homospermidine synthase, HSS) as tool for reconstructing PA evolution. We found hss orthologues in diverse Apocynaceae species, not all of them known to produce PAs. The phylogenetic analysis showed a monophyletic origin of the putative hss sequences early in the evolution of one Apocynaceae lineage (the APSA clade). We found an hss pseudogene in Asclepias syriaca, a species known to produce cardiac glycosides but no PAs, and four losses of an HSS amino acid motif. APSA clade species are significantly more likely to be Danainae larval host plants than expected if all Apocynaceae species were equally likely to be exploited. Our findings are consistent with PA de-escalation as an adaptive response to specialist attack. © 2018 The Authors New Phytologist © 2018 New Phytologist Trust.

  16. Non-immunological defence mechanisms of the gut.

    Science.gov (United States)

    Sarker, S A; Gyr, K

    1992-01-01

    Non-immunological defence mechanisms represent an important line of intestinal defence in addition to humoral and cellular immunity. This review summarises the evidence for the role of the non-immunological defence system. Protective factors that have been amply documented are gastric juice, intestinal motility, and intestinal flora. Components of pancreatic juice, lysozyme, and epithelial cell turnover may also be involved. Special attention is given to gastric acid, infection with Helicobacter pylori, and hypochlorhydria and their association with infectious diarrhoea. Epidemic hypochlorhydria is discussed since this increases sensitivity to intestinal infections in third world countries. PMID:1644343

  17. EU Defence Industry Integration between Spillover and High Politics

    DEFF Research Database (Denmark)

    Kluth, Michael Friederich

    on an intergovernmental base. In the past 10 years, however, the defence industries of the major EU powers have instigated a move from cross national collaboration to cross national consolidation. Cross border mergers and acquisitions has been carried out and pressures for regulatory mainstreaming is mounting......Defence industry regulation falls in between the ‘Low Politics' of ensuring market efficiency and the ‘High Politics' of preserving the national defence industrial and technological base. It has been exempt from internal market regulation and integrative initiatives have been managed...

  18. Defence syndromes in lodgepole - whitebark pine ecosystems relate to degree of historical exposure to mountain pine beetles.

    Science.gov (United States)

    Raffa, Kenneth F; Mason, Charles J; Bonello, Pierluigi; Cook, Stephen; Erbilgin, Nadir; Keefover-Ring, Ken; Klutsch, Jennifer G; Villari, Caterina; Townsend, Philip A

    2017-09-01

    Warming climate is allowing tree-killing bark beetles to expand their ranges and access naïve and semi-naïve conifers. Conifers respond to attack using complex mixtures of chemical defences that can impede beetle success, but beetles exploit some compounds for host location and communication. Outcomes of changing relationships will depend on concentrations and compositions of multiple host compounds, which are largely unknown. We analysed constitutive and induced chemistries of Dendroctonus ponderosae's primary historical host, Pinus contorta, and Pinus albicaulis, a high-elevation species whose encounters with this beetle are transitioning from intermittent to continuous. We quantified multiple classes of terpenes, phenolics, carbohydrates and minerals. Pinus contorta had higher constitutive allocation to, and generally stronger inducibility of, compounds that resist these beetle-fungal complexes. Pinus albicaulis contained higher proportions of specific monoterpenes that enhance pheromone communication, and lower induction of pheromone inhibitors. Induced P. contorta increased insecticidal and fungicidal compounds simultaneously, whereas P. albicaulis responses against these agents were inverse. Induced terpene accumulation was accompanied by decreased non-structural carbohydrates, primarily sugars, in P. contorta, but not P. albicaulis, which contained primarily starches. These results show some host species with continuous exposure to bark beetles have more thoroughly integrated defence syndromes than less-continuously exposed host species. © 2017 John Wiley & Sons Ltd.

  19. The innate host response in caries and periodontitis.

    Science.gov (United States)

    Meyle, Joerg; Dommisch, Henrik; Groeger, Sabine; Giacaman, Rodrigo A; Costalonga, Massimo; Herzberg, Mark

    2017-07-20

    Innate immunity rapidly defends the host against infectious insults. These reactions are of limited specificity and exhaust without providing long-term protection. Functional fluids and effector molecules contribute to the defence against infectious agents, drive the immune response, and direct the cellular players. To review the literature and present a summary of current knowledge about the function of tissues, cellular players and soluble mediators of innate immunity relevant to caries and periodontitis. Historical and recent literature was critically reviewed based on publications in peer-reviewed scientific journals. The innate immune response is vital to resistance against caries and periodontitis and rapidly attempts to protect against infectious agents in the dental hard and soft tissues. Soluble mediators include specialized proteins and lipids. They function to signal to immune and inflammatory cells, provide antimicrobial resistance, and also induce mechanisms for potential repair of damaged tissues. Far less investigated than adaptive immunity, innate immune responses are an emerging scientific and therapeutic frontier. Soluble mediators of the innate response provide a network of signals to organize the near immediate molecular and cellular response to infection, including direct and immediate antimicrobial activity. Further studies in human disease and animal models are generally needed. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  20. 4th International Conference in Software Engineering for Defence Applications

    CERN Document Server

    Sillitti, Alberto; Succi, Giancarlo; Messina, Angelo

    2016-01-01

    This book presents high-quality original contributions on new software engineering models, approaches, methods, and tools and their evaluation in the context of defence and security applications. In addition, important business and economic aspects are discussed, with a particular focus on cost/benefit analysis, new business models, organizational evolution, and business intelligence systems. The contents are based on presentations delivered at SEDA 2015, the 4th International Conference in Software Engineering for Defence Applications, which was held in Rome, Italy, in May 2015. This conference series represents a targeted response to the growing need for research that reports and debates the practical implications of software engineering within the defence environment and also for software performance evaluation in real settings through controlled experiments as well as case and field studies. The book will appeal to all with an interest in modeling, managing, and implementing defence-related software devel...

  1. ZmMPK5 is required for the NADPH oxidase-mediated self-propagation of apoplastic H2O2 in brassinosteroid-induced antioxidant defence in leaves of maize

    OpenAIRE

    Zhang, Aying; Zhang, Jun; Ye, Nenghui; Cao, Jianmei; Tan, Mingpu; Zhang, Jianhua; Jiang, Mingyi

    2010-01-01

    Brassinosteroids (BRs) have been shown to induce hydrogen peroxide (H2O2) accumulation, and BR-induced H2O2 up-regulates antioxidant defence systems in plants. However, the mechanisms by which BR-induced H2O2 regulates antioxidant defence systems in plants remain to be determined. In the present study, the role of ZmMPK5, a mitogen-activated protein kinase, in BR-induced anitioxidant defence and the relationship between the activation of ZmMPK5 and H2O2 production in BR signalling were invest...

  2. Host-bacterial interplay in periodontal disease

    Directory of Open Access Journals (Sweden)

    Rudrakshi Chickanna

    2015-01-01

    Full Text Available A literature search was performed using MEDLINE (PubMed and other electronic basis from 1991 to 2014. Search included books and journals based on the systematic and critical reviews, in vitro and in vivo clinical studies on molecular basis of host microbial interactions. Clearly, an understanding of the host susceptibility factor in addition to microbial factors by elucidating the molecular basis offers opportunity for therapeutic manipulation of advancing periodontal destruction. One of the hallmarks of pathogenesis is the ability of pathogenic organisms to invade surrounding tissues and to evade the host defence. This paper focuses the general overview of molecular mechanisms involved in the microbiota and host response to bacterial inimical behavior in periodontics.

  3. Method of defence of solder surface from oxidization

    Directory of Open Access Journals (Sweden)

    Kurmashev Sh. D.

    2010-02-01

    Full Text Available Compositions are developed for defence of fusion solder from oxidization on the basis of mixture of glycerin, urea and powders of refractory oxides, carbides (Al2O3, TiO2, SIC, graphite. The offered compositions can be used for defence of fusion of solder from oxidization in the process of soludering and tinning of explorers, and also electric conclusions of elements of radio electronic apparatus by the method of immersion in stationary baths.

  4. Ministry of Defence Main Estimates 2009-10

    Science.gov (United States)

    2009-07-02

    Estimates 2009–10 21 Session 2006–07 First Report Defence Procurement 2006 HC 56 (HC 318) Second Report Ministry of Defence Annual Report and...skills strategy Universities and Skills Ministry of Justice 1 Ŕ.050 Centralisation of Tribunals Department for Business 1 ŕ.325 MOD share of the...Government’s Secure Zone Fund costs. HM Treasury 1 Ŕ.045 Transfer to the Centre of Expertise for Sustainable Procurement administration costs—a pan

  5. The Strategic Development of the Trinidad and Tobago Defence Force

    Science.gov (United States)

    2009-06-12

    role played by leadership in the growth environment of the 1950s. As a strategic leadership thinker, Selznick contributed several novel ideas to the... Mintzberg , Ahlstrand, Lampel This research study is about strategy, although not military strategy. Rather, using the Trinidad and Tobago Defence Force...Reserve. A Chief of Defence Staff, usually in the rank of Brigadier General, has operational command and managerial authority over the Force. On

  6. Knowledge as an Inhibitor to Competition in Defence Acquisition

    Science.gov (United States)

    2012-09-01

    suggest that the neoliberal move to globalisation would increase market competitiveness by increasing the number of suppliers. While this argument may...overcapacity and the need to rationalise. Nonetheless, globalisation did not arrest this trend; in fact, it encouraged the development of transnational... Globalisation in the Defence Industry: An exploration of the paradigm for US and European Defence Firms and the implications for being global players

  7. European defence industry consolidation and domestic procurement bias

    DEFF Research Database (Denmark)

    Kluth, Michael Friederich

    2017-01-01

    How have European cross-border defence industrial mergers and acquisitions affected domestic procurement bias among the major EU powers? This article departs from the findings of Andrew Moravcsik more than two decades ago suggesting that major West European states had no ingrained preferences for......-border defence industry consolidation will be analysed. Procurement bias is assessed in two industry segments characterised by pervasive consolidation....

  8. Polymeric Immunoglobulin Receptor-mediated Invasion of Streptococcus pneumoniae into Host Cells Requires a Coordinate Signaling of SRC Family of Protein-tyrosine Kinases, ERK, and c-Jun N-terminal Kinase*

    Science.gov (United States)

    Agarwal, Vaibhav; Asmat, Tauseef M.; Dierdorf, Nina I.; Hauck, Christof R.; Hammerschmidt, Sven

    2010-01-01

    Streptococcus pneumoniae are commensals of the human nasopharynx with the capacity to invade mucosal respiratory cells. PspC, a pneumococcal surface protein, interacts with the human polymeric immunoglobulin receptor (pIgR) to promote bacterial adherence to and invasion into epithelial cells. Internalization of pneumococci requires the coordinated action of actin cytoskeleton rearrangements and the retrograde machinery of pIgR. Here, we demonstrate the involvement of Src protein-tyrosine kinases (PTKs), focal adhesion kinase (FAK), extracellular signal-regulated kinase (ERK), and c-Jun N-terminal kinase (JNK) but not p38 mitogen-activated protein kinases (MAPK) in pneumococcal invasion via pIgR. Pharmacological inhibitors of PTKs and MAPKs and genetic interference with Src PTK and FAK functions caused a significant reduction of pIgR-mediated pneumococcal invasion but did not influence bacterial adhesion to host cells. Furthermore, pneumococcal ingestion by host cells induces activation of ERK1/2 and JNK. In agreement with activated JNK, its target molecule and DNA-binding protein c-Jun was phosphorylated. We also show that functionally active Src PTK is essential for activation of ERK1/2 upon pneumococcal infections. In conclusion, these data illustrate the importance of a coordinated signaling between Src PTKs, ERK1/2, and JNK during PspC-pIgR-mediated uptake of pneumococci by host epithelial cells. PMID:20829350

  9. Polymeric immunoglobulin receptor-mediated invasion of Streptococcus pneumoniae into host cells requires a coordinate signaling of SRC family of protein-tyrosine kinases, ERK, and c-Jun N-terminal kinase.

    Science.gov (United States)

    Agarwal, Vaibhav; Asmat, Tauseef M; Dierdorf, Nina I; Hauck, Christof R; Hammerschmidt, Sven

    2010-11-12

    Streptococcus pneumoniae are commensals of the human nasopharynx with the capacity to invade mucosal respiratory cells. PspC, a pneumococcal surface protein, interacts with the human polymeric immunoglobulin receptor (pIgR) to promote bacterial adherence to and invasion into epithelial cells. Internalization of pneumococci requires the coordinated action of actin cytoskeleton rearrangements and the retrograde machinery of pIgR. Here, we demonstrate the involvement of Src protein-tyrosine kinases (PTKs), focal adhesion kinase (FAK), extracellular signal-regulated kinase (ERK), and c-Jun N-terminal kinase (JNK) but not p38 mitogen-activated protein kinases (MAPK) in pneumococcal invasion via pIgR. Pharmacological inhibitors of PTKs and MAPKs and genetic interference with Src PTK and FAK functions caused a significant reduction of pIgR-mediated pneumococcal invasion but did not influence bacterial adhesion to host cells. Furthermore, pneumococcal ingestion by host cells induces activation of ERK1/2 and JNK. In agreement with activated JNK, its target molecule and DNA-binding protein c-Jun was phosphorylated. We also show that functionally active Src PTK is essential for activation of ERK1/2 upon pneumococcal infections. In conclusion, these data illustrate the importance of a coordinated signaling between Src PTKs, ERK1/2, and JNK during PspC-pIgR-mediated uptake of pneumococci by host epithelial cells.

  10. Defence Policy under the Labour Government: Operational Dynamism and Strategic Inertia’

    OpenAIRE

    Dyson, PTA

    2011-01-01

    This article examines the process and outcome of defence reform under the Labour government, with a particular focus on the structuring of military input to defence planning. It argues that UK defence reform has been characterised by dynamism at the tactical and operational levels but that organisational politics between the services has impacted upon decisions surrounding defence capability procurement and force posture. The core executive has been able to structure military input to defence...

  11. Transformational Leadership in the Estonian Defence Forces

    Directory of Open Access Journals (Sweden)

    Antek Kasemaa

    2015-06-01

    Full Text Available Purpose – The study is a contribution to the validation of the 15 items and 5 subscales Transformational Leadership Scale (TLS proposed by Rafferty and Griffin (2004. Design/methodology/approach – The sample includes participants from different levels of the Estonian Defence Forces (EDF military hierarchy (N=2570. The structure of the TLS was examined by using exploratory and confirmatory factor analyses. Additionally ANOVA was used to compare the results between different subsamples. Findings – TLS showed satisfactory reliability. Confirmatory factor analyses found TLS as valid five dimensions instrument to measure transformational leadership in the Estonian military context. Different management levels showed different emphases among the dimensions of transformational leadership. Research and practical limitations/implications – TLS will be an important tool to use in transformational leadership research in the Estonian military context and beyond. Additionally, the current research contributes to the development of alternative measurement tools besides the most commonly used MLQ. The limitation of the work will be the rather homogenous sample from the Estonian military, however it will open the door for the subsequent research using different samplings. Originality/value – The current research found TLS to be a reliable and valid instrument, very short and therefore easy to administrate, having the possibility to use it with five dimensional and as one general transformational instrument as well.

  12. Impact of environmental factors on lung defences

    Directory of Open Access Journals (Sweden)

    D. Olivieri

    2005-12-01

    Full Text Available The lungs are one of the most important organs exposed to environmental agents. The lungs have the ability to protect themselves by both immunological and nonimmunological mechanisms. An individual's susceptibility to the impact of environmental agents will determine their adverse effects. This article focuses on air pollution, in particular ozone (O3, nitrogen dioxide (NO2, particulate matter (PM and sulphur dioxide (SO2. O3 inhalation first modifies the ciliary cells. O3 is an extremely strong oxidant, since it increases the permeability of epithelial cells and decreases mucociliary clearance. NO2 is a less potent and less reactive oxidant pollutant and impairs the function of epithelial cells and alveolar macrophages. PM induces oxidative stress in macrophages and epithelial cells, and increases tumour necrosis factor-beta, interleukin (IL-6, interferon-gamma, transforming growth factor-beta and nuclear factor-kappaB. Diesel exhaust particulate, contained in PM, increases IL-8 production. High concentrations of SO2 increase the production of reactive oxygen species in the lungs. In conclusion, air pollution certainly interferes with aspecific and specific lung defences, thus facilitating the development of pulmonary diseases, such as exacerbation of chronic obstructive pulmonary disease, allergies and asthma.

  13. Between-population outbreeding affects plant defence.

    Directory of Open Access Journals (Sweden)

    Roosa Leimu

    Full Text Available Between-population crosses may replenish genetic variation of populations, but may also result in outbreeding depression. Apart from direct effects on plant fitness, these outbreeding effects can also alter plant-herbivore interactions by influencing plant tolerance and resistance to herbivory. We investigated effects of experimental within- and between-population outbreeding on herbivore resistance, tolerance and plant fitness using plants from 13 to 19 Lychnis flos-cuculi populations. We found no evidence for outbreeding depression in resistance reflected by the amount of leaf area consumed. However, herbivore performance was greater when fed on plants from between-population compared to within-population crosses. This can reflect outbreeding depression in resistance and/or outbreeding effects on plant quality for the herbivores. The effects of type of cross on the relationship between herbivore damage and plant fitness varied among populations. This demonstrates how between-population outbreeding effects on tolerance range from outbreeding depression to outbreeding benefits among plant populations. Finally, herbivore damage strengthened the observed outbreeding effects on plant fitness in several populations. These results raise novel considerations on the impact of outbreeding on the joint evolution of resistance and tolerance, and on the evolution of multiple defence strategies.

  14. [Personality characteristics, defence mechanisms and binge eating in obese patients].

    Science.gov (United States)

    Pozzoli, S; Drago, C; Zanardi, G; Negri, M; Giorgi, I

    2007-01-01

    This study aimed to investigate defence mechanisms and personality characteristics in obese subjects. In particular, we compared the use of defence mechanisms in two groups: obese persons vs. normal weight subjects. We also compared the defence mechanisms and personality characteristics of two groups of obese subjects: those with Binge Eating Disorder vs. those without this disorder. Finally, we investigated the presence of possible differences linked to gender or to age of onset of obesity. 93 obese subjects and 68 normal weight subjects were administered a test battery composed of the following self-complete questionnaires (in the Italian version): Binge Eating Scale, Response Evaluation Measure-71, Eating Disorder Inventory-2 and Minnesota Multiphasic Personality Inventory). Obese subjects appear to use specific defence mechanisms. A gender effect was found on the use of defence mechanisms, on the psychological characteristics associated to an Eating Disorder and on personality features. Obese subjects with Binge Eating Disorder showed a marked tendency to manifest anxiety and bulimic behaviour. Obesity with onset in adolescence was associated with the possibility of developing drug dependence. Specific defence characteristics and personality features in obese subjects should be taken into account in designing a slimming program.

  15. Expression profiles of defence related cDNAs in oil palm (Elaeis guineensis Jacq.) inoculated with mycorrhizae and Trichoderma harzianum Rifai T32.

    Science.gov (United States)

    Tan, Yung-Chie; Wong, Mui-Yun; Ho, Chai-Ling

    2015-11-01

    Basal stem rot is one of the major diseases of oil palm (Elaies guineensis Jacq.) caused by pathogenic Ganoderma species. Trichoderma and mycorrhizae were proposed to be able to reduce the disease severity. However, their roles in improving oil palm defence system by possibly inducing defence-related genes in the host are not well characterized. To better understand that, transcript profiles of eleven putative defence-related cDNAs in the roots of oil palm inoculated with Trichoderma harzianum T32 and mycorrhizae at different time points were studied. Transcripts encoding putative Bowman-Birk protease inhibitor (EgBBI2) and defensin (EgDFS) increased more than 2 fold in mycorrhizae-treated roots at 6 weeks post inoculation (wpi) compared to those in controls. Transcripts encoding putative dehydrin (EgDHN), glycine-rich RNA binding protein (EgGRRBP), isoflavone reductase (EgIFR), type 2 ribosome inactivating protein (EgT2RIP), and EgDFS increased in the oil palm roots treated with T. harzianum at 6 and/or 12 wpi compared to those in the controls. Some of these genes were also expressed in oil palm roots treated with Ganoderma boninense. This study provides an insight of some defence-related genes induced by Trichoderma and mycorrhizae, and their roles as potential agents to boost the plant defence system. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  16. Ectoparasite reproductive performance when host condition varies.

    Science.gov (United States)

    Rueesch, Shona; Lemoine, Mélissa; Richner, Heinz

    2012-09-01

    Host condition can influence both the nutritive resources available to parasites and the strength of host defences. Since these factors are likely to be correlated, it is unclear whether parasites would be more successful on hosts in good, intermediate or poor conditions. For more complex parasites, like fleas, where larvae depend on adults to extract and make available some essential host resources, host condition can act at two levels. First, it can affect the investment of females into eggs, and second, it can influence offspring growth. In a two-step experiment, we first let female hen fleas Ceratophyllus gallinae feed on nestlings of reduced, control or enlarged great tit Parus major broods and secondly used the blood from these nestlings as a food source for flea larvae reared in the laboratory. We then assessed the effect of brood size manipulation on reproductive investment and survival of female fleas, and on survival, developmental time, mass and size of pre-imago larvae and adults of the first generation. Although host condition, measured as body mass controlled for body size, was significantly influenced by brood size manipulation, it did not affect the female fleas' reproductive investment and survival. Larvae fed with blood from nestlings of reduced broods lived longer, however, than larvae fed on blood from enlarged or control broods. Additionally, F1 adults grew shorter tibiae when their mother had fed on hosts of reduced broods. The finding that brood size manipulation influenced parasite reproduction suggests that it affected nutritive resources and/or host defence, but the precise mechanism or balance between the two requires further investigation.

  17. EST sequencing and gene expression profiling of defence-related genes from Persea americana infected with Phytophthora cinnamomi.

    Science.gov (United States)

    Mahomed, Waheed; Berg, Noëlani van den

    2011-11-23

    Avocado (Persea americana) belongs to the Lauraceae family and is an important commercial fruit crop in over 50 countries. The most serious pathogen affecting avocado production is Phytophthora cinnamomi which causes Phytophthora root rot (PRR). Root pathogens such as P. cinnamomi and their interactions with hosts are poorly understood and despite the importance of both the avocado crop and the effect Phytophthora has on its cultivation, there is a lack of molecular knowledge underpinning our understanding of defence strategies against the pathogen. In order to initiate a better understanding of host-specific defence we have generated EST data using 454 pyrosequencing and profiled nine defence-related genes from Pc-infected avocado roots. 2.0 Mb of data was generated consisting of ~10,000 reads on a single lane of the GS FLX platform. Using the Newbler assembler 371 contigs were assembled, of which 367 are novel for Persea americana. Genes were classified according to Gene Ontology terms. In addition to identifying root-specific ESTs we were also able to identify and quantify the expression of nine defence-related genes that were differentially regulated in response to P. cinnamomi. Genes such as metallothionein, thaumatin and the pathogenesis related PsemI, mlo and profilin were found to be differentially regulated. This is the first study in elucidating the avocado root transcriptome as well as identifying defence responses of avocado roots to the root pathogen P. cinnamomi. Our data is currently the only EST data that has been generated for avocado rootstocks, and the ESTs identified in this study have already been useful in identifying defence-related genes as well as providing gene information for other studies looking at processes such as ROS regulation as well as hypoxia in avocado roots. Our EST data will aid in the elucidation of the avocado transcriptome and identification of markers for improved rootstock breeding and screening. The characterization of

  18. EST sequencing and gene expression profiling of defence-related genes from Persea americana infected with Phytophthora cinnamomi

    Directory of Open Access Journals (Sweden)

    Mahomed Waheed

    2011-11-01

    Full Text Available Abstract Background Avocado (Persea americana belongs to the Lauraceae family and is an important commercial fruit crop in over 50 countries. The most serious pathogen affecting avocado production is Phytophthora cinnamomi which causes Phytophthora root rot (PRR. Root pathogens such as P. cinnamomi and their interactions with hosts are poorly understood and despite the importance of both the avocado crop and the effect Phytophthora has on its cultivation, there is a lack of molecular knowledge underpinning our understanding of defence strategies against the pathogen. In order to initiate a better understanding of host-specific defence we have generated EST data using 454 pyrosequencing and profiled nine defence-related genes from Pc-infected avocado roots. Results 2.0 Mb of data was generated consisting of ~10,000 reads on a single lane of the GS FLX platform. Using the Newbler assembler 371 contigs were assembled, of which 367 are novel for Persea americana. Genes were classified according to Gene Ontology terms. In addition to identifying root-specific ESTs we were also able to identify and quantify the expression of nine defence-related genes that were differentially regulated in response to P. cinnamomi. Genes such as metallothionein, thaumatin and the pathogenesis related PsemI, mlo and profilin were found to be differentially regulated. Conclusions This is the first study in elucidating the avocado root transcriptome as well as identifying defence responses of avocado roots to the root pathogen P. cinnamomi. Our data is currently the only EST data that has been generated for avocado rootstocks, and the ESTs identified in this study have already been useful in identifying defence-related genes as well as providing gene information for other studies looking at processes such as ROS regulation as well as hypoxia in avocado roots. Our EST data will aid in the elucidation of the avocado transcriptome and identification of markers for improved

  19. Hypoxia inducible factor signaling modulates susceptibility to mycobacterial infection via a nitric oxide dependent mechanism.

    Science.gov (United States)

    Elks, Philip M; Brizee, Sabrina; van der Vaart, Michiel; Walmsley, Sarah R; van Eeden, Fredericus J; Renshaw, Stephen A; Meijer, Annemarie H

    2013-01-01

    Tuberculosis is a current major world-health problem, exacerbated by the causative pathogen, Mycobacterium tuberculosis (Mtb), becoming increasingly resistant to conventional antibiotic treatment. Mtb is able to counteract the bactericidal mechanisms of leukocytes to survive intracellularly and develop a niche permissive for proliferation and dissemination. Understanding of the pathogenesis of mycobacterial infections such as tuberculosis (TB) remains limited, especially for early infection and for reactivation of latent infection. Signaling via hypoxia inducible factor α (HIF-α) transcription factors has previously been implicated in leukocyte activation and host defence. We have previously shown that hypoxic signaling via stabilization of Hif-1α prolongs the functionality of leukocytes in the innate immune response to injury. We sought to manipulate Hif-α signaling in a well-established Mycobacterium marinum (Mm) zebrafish model of TB to investigate effects on the host's ability to combat mycobacterial infection. Stabilization of host Hif-1α, both pharmacologically and genetically, at early stages of Mm infection was able to reduce the bacterial burden of infected larvae. Increasing Hif-1α signaling enhanced levels of reactive nitrogen species (RNS) in neutrophils prior to infection and was able to reduce larval mycobacterial burden. Conversely, decreasing Hif-2α signaling enhanced RNS levels and reduced bacterial burden, demonstrating that Hif-1α and Hif-2α have opposing effects on host susceptibility to mycobacterial infection. The antimicrobial effect of Hif-1α stabilization, and Hif-2α reduction, were demonstrated to be dependent on inducible nitric oxide synthase (iNOS) signaling at early stages of infection. Our findings indicate that induction of leukocyte iNOS by stabilizing Hif-1α, or reducing Hif-2α, aids the host during early stages of Mm infection. Stabilization of Hif-1α therefore represents a potential target for therapeutic

  20. Hypoxia inducible factor signaling modulates susceptibility to mycobacterial infection via a nitric oxide dependent mechanism.

    Directory of Open Access Journals (Sweden)

    Philip M Elks

    Full Text Available Tuberculosis is a current major world-health problem, exacerbated by the causative pathogen, Mycobacterium tuberculosis (Mtb, becoming increasingly resistant to conventional antibiotic treatment. Mtb is able to counteract the bactericidal mechanisms of leukocytes to survive intracellularly and develop a niche permissive for proliferation and dissemination. Understanding of the pathogenesis of mycobacterial infections such as tuberculosis (TB remains limited, especially for early infection and for reactivation of latent infection. Signaling via hypoxia inducible factor α (HIF-α transcription factors has previously been implicated in leukocyte activation and host defence. We have previously shown that hypoxic signaling via stabilization of Hif-1α prolongs the functionality of leukocytes in the innate immune response to injury. We sought to manipulate Hif-α signaling in a well-established Mycobacterium marinum (Mm zebrafish model of TB to investigate effects on the host's ability to combat mycobacterial infection. Stabilization of host Hif-1α, both pharmacologically and genetically, at early stages of Mm infection was able to reduce the bacterial burden of infected larvae. Increasing Hif-1α signaling enhanced levels of reactive nitrogen species (RNS in neutrophils prior to infection and was able to reduce larval mycobacterial burden. Conversely, decreasing Hif-2α signaling enhanced RNS levels and reduced bacterial burden, demonstrating that Hif-1α and Hif-2α have opposing effects on host susceptibility to mycobacterial infection. The antimicrobial effect of Hif-1α stabilization, and Hif-2α reduction, were demonstrated to be dependent on inducible nitric oxide synthase (iNOS signaling at early stages of infection. Our findings indicate that induction of leukocyte iNOS by stabilizing Hif-1α, or reducing Hif-2α, aids the host during early stages of Mm infection. Stabilization of Hif-1α therefore represents a potential target for

  1. Stennis hosts 2010 Special Olympics

    Science.gov (United States)

    2010-01-01

    Sarah Johnson, 28, of Gulfport, carries in the Olympic torch to signal the start of the 2010 Area III Special Olympic games at NASA's John C. Stennis Space Center on March 27. Stennis volunteers hosted special needs athletes from across the area for the event. Stennis is an annual host of the games.

  2. Innate immune defences in the human endometrium

    Directory of Open Access Journals (Sweden)

    Kelly Rodney W

    2003-11-01

    Full Text Available Abstract The human endometrium is an important site of innate immune defence, giving protection against uterine infection. Such protection is critical to successful implantation and pregnancy. Infection is a major cause of preterm birth and can also cause infertility and ectopic pregnancy. Natural anti-microbial peptides are key mediators of the innate immune system. These peptides, between them, have anti-bacterial, anti-fungal and anti-viral activity and are expressed at epithelial surfaces throughout the female genital tract. Two families of natural anti-microbials, the defensins and the whey acidic protein (WAP motif proteins, appear to be prominent in endometrium. The human endometrial epithelium expresses beta-defensins 1–4 and the WAP motif protein, secretory leukocyte protease inhibitor. Each beta-defensin has a different expression profile in relation to the stage of the menstrual cycle, providing potential protection throughout the cycle. Secretory leukocyte protease inhibitor is expressed during the secretory phase of the cycle and has a range of possible roles including anti-protease and anti-microbial activity as well as having effects on epithelial cell growth. The leukocyte populations in the endometrium are also a source of anti-microbial production. Neutrophils are a particularly rich source of alpha-defensins, lactoferrin, lysozyme and the WAP motif protein, elafin. The presence of neutrophils during menstruation will enhance anti-microbial protection at a time when the epithelial barrier is disrupted. Several other anti-microbials including the natural killer cell product, granulysin, are likely to have a role in endometrium. The sequential production of natural anti-microbial peptides by the endometrium throughout the menstrual cycle and at other sites in the female genital tract will offer protection from many pathogens, including those that are sexually transmitted.

  3. Culture of an aphid heritable symbiont demonstrates its direct role in defence against parasitoids.

    Science.gov (United States)

    Brandt, Jayce W; Chevignon, Germain; Oliver, Kerry M; Strand, Michael R

    2017-11-15

    Heritable symbionts are common in insects with many contributing to host defence. Hamiltonella defensa is a facultative, bacterial symbiont of the pea aphid, Acyrthosiphon pisum that provides protection against the endoparasitoid wasp Aphidius ervi Protection levels vary among strains of H. defensa that are differentially infected by bacteriophages named APSEs. By contrast, little is known about mechanism(s) of resistance owing to the intractability of host-restricted microbes for functional study. Here, we developed methods for culturing strains of H. defensa that varied in the presence and type of APSE. Most H. defensa strains proliferated at 27°C in co-cultures with the TN5 cell line or as pure cultures with no insect cells. The strain infected by APSE3, which provides high levels of protection in vivo, produced a soluble factor(s) that disabled development of A. ervi embryos independent of any aphid factors. Experimental transfer of APSE3 also conferred the ability to disable A. ervi development to a phage-free strain of H. defensa Altogether, these results provide a critical foundation for characterizing symbiont-derived factor(s) involved in host protection and other functions. Our results also demonstrate that phage-mediated transfer of traits provides a mechanism for innovation in host restricted symbionts. © 2017 The Author(s).

  4. HumanViCe: Host ceRNA network in virus infected cells in human

    Directory of Open Access Journals (Sweden)

    Suman eGhosal

    2014-07-01

    Full Text Available Host-virus interaction via host cellular components has been an important field of research in recent times. RNA interference mediated by short interfering RNAs and microRNAs (miRNA, is a widespread anti-viral defence strategy. Importantly, viruses also encode their own miRNAs. In recent times miRNAs were identified as key players in host-virus interaction. Furthermore, viruses were shown to exploit the host miRNA networks to suite their own need. The complex cross-talk between host and viral miRNAs and their cellular and viral targets forms the environment for viral pathogenesis. Apart from protein-coding mRNAs, non-coding RNAs may also be targeted by host or viral miRNAs in virus infected cells, and viruses can exploit the host miRNA mediated gene regulatory network via the competing endogenous RNA effect. A recent report showed that viral U-rich non-coding RNAs called HSUR, expressed in primate virus herpesvirus saimiri (HVS infected T cells, were able to bind to three host miRNAs, causing significant alteration in cellular level for one of the miRNAs. We have predicted protein coding and non protein-coding targets for viral and human miRNAs in virus infected cells. We identified viral miRNA targets within host non-coding RNA loci from AGO interacting regions in three different virus infected cells. Gene ontology (GO and pathway enrichment analysis of the genes comprising the ceRNA networks in the virus infected cells revealed enrichment of key cellular signalling pathways related to cell fate decisions and gene transcription, like Notch and Wnt signalling pathways, as well as pathways related to viral entry, replication and virulence. We identified a vast number of non-coding transcripts playing as potential ceRNAs to the immune response associated genes; e.g. APOBEC family genes, in some virus infected cells. All these information are compiled in HumanViCe, a comprehensive database that provides the potential ceRNA networks in virus

  5. IL-17A and Th17 Cells in Lung Inflammation: An Update on the Role of Th17 Cell Differentiation and IL-17R Signaling in Host Defense against Infection

    Directory of Open Access Journals (Sweden)

    Hsing-Chuan Tsai

    2013-01-01

    Full Text Available The significance of Th17 cells and interleukin- (IL-17A signaling in host defense and disease development has been demonstrated in various infection and autoimmune models. Numerous studies have indicated that Th17 cells and its signature cytokine IL-17A are critical to the airway’s immune response against various bacteria and fungal infection. Cytokines such as IL-23, which are involved in Th17 differentiation, play a critical role in controlling Klebsiella pneumonia (K. pneumonia infection. IL-17A acts on nonimmune cells in infected tissues to strengthen innate immunity by inducing the expression of antimicrobial proteins, cytokines, and chemokines. Mice deficient in IL-17 receptor (IL-17R expression are susceptible to infection by various pathogens. In this review, we summarize the recent advances in unraveling the mechanism behind Th17 cell differentiation, IL-17A/IL-17R signaling, and also the importance of IL-17A in pulmonary infection.

  6. Gene coevolution and regulation lock cyclic plant defence peptides to their targets.

    Science.gov (United States)

    Gilding, Edward K; Jackson, Mark A; Poth, Aaron G; Henriques, Sónia Troeira; Prentis, Peter J; Mahatmanto, Tunjung; Craik, David J

    2016-04-01

    Plants have evolved many strategies to protect themselves from attack, including peptide toxins that are ribosomally synthesized and thus adaptable directly by genetic polymorphisms. Certain toxins in Clitoria ternatea (butterfly pea) are cyclic cystine-knot peptides of c. 30 residues, called cyclotides, which have co-opted the plant's albumin-1 gene family for their production. How butterfly pea albumin-1 genes were commandeered and how these cyclotides are utilized in defence remain unclear. The role of cyclotides in host plant ecology and biotechnological applications requires exploration. We characterized the sequence diversity and expression dynamics of precursor and processing proteins implicated in butterfly pea cyclotide biosynthesis by expression profiling through RNA-sequencing (RNA-seq). Peptide-enriched extracts from various organs were tested for activity against insect-like membranes and the model nematode Caenorhabditis elegans. We found that the evolution and deployment of cyclotides involved their diversification to exhibit different chemical properties and expression between organs facing different defensive challenges. Cyclotide-enriched fractions from soil-contacting organs were effective at killing nematodes, whereas similar enriched fractions from aerial organs contained cyclotides that exhibited stronger interactions with insect-like membrane lipids. Cyclotides are employed as versatile and combinatorial mediators of defence in C. ternatea and have specialized to affect different classes of attacking organisms. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

  7. Glial-cell-derived neuroregulators control type 3 innate lymphoid cells and gut defence.

    Science.gov (United States)

    Ibiza, Sales; García-Cassani, Bethania; Ribeiro, Hélder; Carvalho, Tânia; Almeida, Luís; Marques, Rute; Misic, Ana M; Bartow-McKenney, Casey; Larson, Denise M; Pavan, William J; Eberl, Gérard; Grice, Elizabeth A; Veiga-Fernandes, Henrique

    2016-07-21

    Group 3 innate lymphoid cells (ILC3) are major regulators of inflammation and infection at mucosal barriers. ILC3 development is thought to be programmed, but how ILC3 perceive, integrate and respond to local environmental signals remains unclear. Here we show that ILC3 in mice sense their environment and control gut defence as part of a glial–ILC3–epithelial cell unit orchestrated by neurotrophic factors. We found that enteric ILC3 express the neuroregulatory receptor RET. ILC3-autonomous Ret ablation led to decreased innate interleukin-22 (IL-22), impaired epithelial reactivity, dysbiosis and increased susceptibility to bowel inflammation and infection. Neurotrophic factors directly controlled innate Il22 downstream of the p38 MAPK/ERK-AKT cascade and STAT3 activation. Notably, ILC3 were adjacent to neurotrophic-factor-expressing glial cells that exhibited stellate-shaped projections into ILC3 aggregates. Glial cells sensed microenvironmental cues in a MYD88-dependent manner to control neurotrophic factors and innate IL-22. Accordingly, glial-intrinsic Myd88 deletion led to impaired production of ILC3-derived IL-22 and a pronounced propensity towards gut inflammation and infection. Our work sheds light on a novel multi-tissue defence unit, revealing that glial cells are central hubs of neuron and innate immune regulation by neurotrophic factor signals.

  8. Evaluating arguments during instigations of defence motivation and accuracy motivation.

    Science.gov (United States)

    Liu, Cheng-Hong

    2017-05-01

    When people evaluate the strength of an argument, their motivations are likely to influence the evaluation. However, few studies have specifically investigated the influences of motivational factors on argument evaluation. This study examined the effects of defence and accuracy motivations on argument evaluation. According to the compatibility between the advocated positions of arguments and participants' prior beliefs and the objective strength of arguments, participants evaluated four types of arguments: compatible-strong, compatible-weak, incompatible-strong, and incompatible-weak arguments. Experiment 1 revealed that participants possessing a high defence motivation rated compatible-weak arguments as stronger and incompatible-strong ones as weaker than participants possessing a low defence motivation. However, the strength ratings between the high and low defence groups regarding both compatible-strong and incompatible-weak arguments were similar. Experiment 2 revealed that when participants possessed a high accuracy motivation, they rated compatible-weak arguments as weaker and incompatible-strong ones as stronger than when they possessed a low accuracy motivation. However, participants' ratings on both compatible-strong and incompatible-weak arguments were similar when comparing high and low accuracy conditions. The results suggest that defence and accuracy motivations are two major motives influencing argument evaluation. However, they primarily influence the evaluation results for compatible-weak and incompatible-strong arguments, but not for compatible-strong and incompatible-weak arguments. © 2016 The British Psychological Society.

  9. SseK3 Is a Salmonella Effector That Binds TRIM32 and Modulates the Host's NF-κB Signalling Activity.

    Directory of Open Access Journals (Sweden)

    Zhe Yang

    Full Text Available Salmonella Typhimurium employs an array of type III secretion system effectors that facilitate intracellular survival and replication during infection. The Salmonella effector SseK3 was originally identified due to amino acid sequence similarity with NleB; an effector secreted by EPEC/EHEC that possesses N-acetylglucoasmine (GlcNAc transferase activity and modifies death domain containing proteins to block extrinsic apoptosis. In this study, immunoprecipitation of SseK3 defined a novel molecular interaction between SseK3 and the host protein, TRIM32, an E3 ubiquitin ligase. The conserved DxD motif within SseK3, which is essential for the GlcNAc transferase activity of NleB, was required for TRIM32 binding and for the capacity of SseK3 to suppress TNF-stimulated activation of NF-κB pathway. However, we did not detect GlcNAc modification of TRIM32 by SseK3, nor did the SseK3-TRIM32 interaction impact on TRIM32 ubiquitination that is associated with its activation. In addition, lack of sseK3 in Salmonella had no effect on production of the NF-κB dependent cytokine, IL-8, in HeLa cells even though TRIM32 knockdown suppressed TNF-induced NF-κB activity. Ectopically expressed SseK3 partially co-localises with TRIM32 at the trans-Golgi network, but SseK3 is not recruited to Salmonella induced vacuoles or Salmonella induced filaments during Salmonella infection. Our study has identified a novel effector-host protein interaction and suggests that SseK3 may influence NF-κB activity. However, the lack of GlcNAc modification of TRIM32 suggests that SseK3 has further, as yet unidentified, host targets.

  10. Covariance in species diversity and facilitation among non-interactive parasite taxa: all against the host.

    Science.gov (United States)

    Krasnov, B R; Mouillot, D; Khokhlova, I S; Shenbrot, G I; Poulin, R

    2005-10-01

    Different parasite taxa exploit different host resources and are often unlikely to interact directly. It is unclear, however, whether the diversity of any given parasite taxon is indirectly influenced by that of other parasite taxa on the same host. Some components of host immune defences may operate simultaneously against all kinds of parasites, whereas investment by the host in specific defences against one type of parasite may come at the expense of defence against other parasites. We investigated the relationships between the species diversity of 4 higher taxa of ectoparasites (fleas, sucking lice, mesostigmatid mites, and ixodid ticks), and between the species richness of ectoparasites and endoparasitic helminths, across different species of rodent hosts. Our analyses used 2 measures of species diversity, species richness and taxonomic distinctness, and controlled for the potentially confounding effects of sampling effort and phylogenetic relationships among host species. We found positive pairwise correlations between the species richness of fleas, mites and ticks; however, there was no association between species richness of any of these 3 groups and that of lice. We also found a strong positive relationship between the taxonomic distinctness of ecto- and endoparasite assemblages across host species. These results suggest the existence of a process of apparent facilitation among unrelated taxa in the organization of parasite communities. We propose explanations based on host immune responses, involving acquired cross-resistance to infection and interspecific variation in immunocompetence among hosts, to account for these patterns.

  11. Phytoplankton defence mechanisms: traits and trade-offs

    DEFF Research Database (Denmark)

    Pančić, Marina; Kiørboe, Thomas

    2018-01-01

    In aquatic ecosystems, unicellular algae form the basis of the food webs. Theoretical and experimental studies have demonstrated that one of the mechanisms that maintain high diversity of phytoplankton is through predation and the consequent evolution of defence mechanisms. Proposed defence...... mechanisms in phytoplankton are diverse and include physiological (e.g. toxicity, bioluminescence), morphological (e.g. silica shell, colony formation), and behavioural (e.g. escape response) traits. However, the function of many of the proposed defence mechanisms remains elusive, and the costs and benefits...... (trade-offs) are often unquantified or undocumented. Here, we provide an overview of suggested phytoplankton defensive traits and review their experimental support. Wherever possible we quantify the trade-offs from experimental evidence and theoretical considerations. In many instances, experimental...

  12. Jasmonate-mediated defence responses, unlike salicylate-mediated responses, are involved in the recovery of grapevine from bois noir disease.

    Science.gov (United States)

    Paolacci, Anna Rita; Catarcione, Giulio; Ederli, Luisa; Zadra, Claudia; Pasqualini, Stefania; Badiani, Maurizio; Musetti, Rita; Santi, Simonetta; Ciaffi, Mario

    2017-07-10

    Bois noir is an important disease of grapevine (Vitis vinifera L.), caused by phytoplasmas. An interesting, yet elusive aspect of the bois noir disease is "recovery", i.e., the spontaneous and unpredictable remission of symptoms and damage. Because conventional pest management is ineffective against bois noir, deciphering the molecular bases of recovery is beneficial. The present study aimed to understand whether salicylate- and jasmonate-defence pathways might have a role in the recovery from the bois noir disease of grapevine. Leaves from healthy, bois noir-diseased and bois noir-recovered plants were compared, both in the presence (late summer) and absence (late spring) of bois noir symptoms on the diseased plants. Analyses of salicylate and jasmonate contents, as well as the expression of genes involved in their biosynthesis, signalling and action, were evaluated. In symptomatic diseased plants (late summer), unlike symptomless plants (late spring), salicylate biosynthesis was increased and salicylate-responsive genes were activated. In contrast, jasmonate biosynthesis and signalling genes were up-regulated both in recovered and diseased plants at all sampling dates. The activation of salicylate signalling in symptomatic plants might have antagonised the jasmonate-mediated defence response by suppressing the expression of jasmonate-responsive genes. Our results suggest that grapevine reacts to phytoplasma infection through salicylate-mediated signalling, although the resultant full activation of a salicylate-mediated response is apparently ineffective in conferring resistance against bois noir disease. Activation of the salicylate signalling pathway that is associated with the presence of bois noir phytoplasma seems to antagonise the jasmonate defence response, by failing to activate or suppressing both the expression of some jasmonate responsive genes that act downstream of the jasmonate biosynthetic pathway, as well as the first events of the jasmonate

  13. Pseudomonas Aeruginosa: interactions with organisms in the environment and cells of the immune defence

    DEFF Research Database (Denmark)

    Skindersø, Mette Elena

    2008-01-01

    Pseudomonas aeruginosa is an increasingly prevalent opportunistic pathogen which causes chronic pneumonia in cystic fibrosis patients and severe life-threatening infections in immunocompromised persons. This pathogen produces a range of malicious virulence factors such as toxins, tissue degrading...... enzymes and components capable of impairing the hosts’ immunity. P. aeruginosa readily assumes the biofilm lifestyle which confers efficient protection against the activity of the host defence system. In addition, P. aeruginosa exhibit an inherent tolerance to many of the antibiotics most commonly used......, it suggests that the ability to produce them either has evolved in parallel in different organisms or that the ability to produce such compounds is a reminiscence of an ancient shared ancestor (of a range of marine invertebrates and microfungi), the trait of which has been maintained through times...

  14. Regulation of OspE-related, OspF-related, and Elp lipoproteins of Borrelia burgdorferi strain 297 by mammalian host-specific signals.

    Science.gov (United States)

    Hefty, P S; Jolliff, S E; Caimano, M J; Wikel, S K; Radolf, J D; Akins, D R

    2001-06-01

    In previous studies we have characterized the cp32/18 loci in Borrelia burgdorferi 297 which encode OspE and OspF orthologs and a third group of lipoproteins which possess OspE/F-like leader peptides (Elps). To further these studies, we have comprehensively analyzed their patterns of expression throughout the borrelial enzootic cycle. Serial dilution reverse transcription-PCR analysis indicated that although a shift in temperature from 23 to 37 degrees C induced transcription for all nine genes analyzed, this effect was often markedly enhanced in mammalian host-adapted organisms cultivated within dialysis membrane chambers (DMCs) implanted within the peritoneal cavities of rats. Indirect immunofluorescence assays performed on temperature-shifted, in vitro-cultivated spirochetes and organisms in the midguts of unfed and fed ticks revealed distinct expression profiles for many of the OspE-related, OspF-related, and Elp proteins. Other than BbK2.10 and ElpA1, all were expressed by temperature-shifted organisms, while only OspE, ElpB1, OspF, and BbK2.11 were expressed in the midguts of fed ticks. Additionally, although mRNA was detected for all nine lipoprotein-encoding genes, two of these proteins (BbK2.10 and ElpA1) were not expressed by spirochetes cultivated in vitro, within DMCs, or by spirochetes within tick midguts. However, the observation that B. burgdorferi-infected mice generated specific antibodies against BbK2.10 and ElpA1 indicated that these antigens are expressed only in the mammalian host and that a form of posttranscriptional regulation is involved. Analysis of the upstream regions of these genes revealed several differences between their promoter regions, the majority of which were found in the -10 and -35 hexamers and the spacer regions between them. Also, rather than undergoing simultaneous upregulation during tick feeding, these genes and the corresponding lipoproteins appear to be subject to progressive recruitment or enhancement of expression as

  15. Defence mechanisms and immune evasion in the interplay between the humane immune system and Plasmodium falciparum

    DEFF Research Database (Denmark)

    Theander, T G

    1992-01-01

    antigens, which probably is precipitated by defects in the early events of T-cell activation and inhibition of IL-2 function elucidated, but soluble factors secreted either by the parasites, or by host cells as a result of exposure to the parasite, seem to be involved. 4) Immune effector mechanisms...... in the liver and the spleen are avoided by sequestration of the mature parasites to the vascular endothelium. The interplay between the human defence system and the malaria parasite governs the symptomatology, the pathology and the development of immunity to the disease. These interactions are extremely...

  16. Quantitative Verification and Synthesis of Attack-Defence Scenarios

    DEFF Research Database (Denmark)

    Aslanyan, Zaruhi; Nielson, Flemming; Parker, David

    2016-01-01

    -defence trees to two-player stochastic games, and then employ probabilistic model checking techniques to formally analyse these models. This provides a means to both verify formally specified security properties of the attack-defence scenarios and, dually, to synthesise strategies for attackers or defenders...... which guarantee or optimise some quantitative property, such as the probability of a successful attack, the expected cost incurred, or some multi-objective trade-off between the two. We implement our approach, building upon the PRISM-games model checker, and apply it to a case study of an RFID goods...

  17. Complexity of the Microglial Activation Pathways that Drive Innate Host Responses During Lethal Alphavirus Encephalitis in Mice

    Directory of Open Access Journals (Sweden)

    Nilufer Esen

    2012-04-01

    Full Text Available Microglia express multiple TLRs (Toll-like receptors and provide important host defence against viruses that invade the CNS (central nervous system. Although prior studies show these cells become activated during experimental alphavirus encephalitis in mice to generate cytokines and chemokines that influence virus replication, tissue inflammation and neuronal survival, the specific PRRs (pattern recognition receptors and signalling intermediates controlling microglial activation in this setting remain unknown. To investigate these questions directly in vivo, mice ablated of specific TLR signalling molecules were challenged with NSV (neuroadapted Sindbis virus and CNS viral titres, inflammatory responses and clinical outcomes followed over time. To approach this problem specifically in microglia, the effects of NSV on primary cells derived from the brains of wild-type and mutant animals were characterized in vitro. From the standpoint of the virus, microglial activation required viral uncoating and an intact viral genome; inactivated virus particles did not elicit measurable microglial responses. At the level of the target cell, NSV triggered multiple PRRs in microglia to produce a broad range of inflammatory mediators via non-overlapping signalling pathways. In vivo, disease survival was surprisingly independent of TLR-driven responses, but still required production of type-I IFN (interferon to control CNS virus replication. Interestingly, the ER (endoplasmic reticulum protein UNC93b1 facilitated host survival independent of its known effects on endosomal TLR signalling. Taken together, these data show that alphaviruses activate microglia via multiple PRRs, highlighting the complexity of the signalling networks by which CNS host responses are elicited by these infections.

  18. Towards the single european EMC defence standard AECTP 250-500, and planned updates

    NARCIS (Netherlands)

    Leferink, Frank Bernardus Johannes

    2013-01-01

    The European Commission is supporting one European wide defence (equipment) market, and national standards are preventing such a European-wide approach. Therefore the European Standardisation organisation CEN was asked to create an organisation to rationalize standards for defence procurement.

  19. Blocking the QB-binding site of photosystem II by tenuazonic acid, a non-host-specific toxin of Alternaria alternata, activates singlet oxygen-mediated and EXECUTER-dependent signalling in Arabidopsis.

    Science.gov (United States)

    Chen, Shiguo; Kim, Chanhong; Lee, Je Min; Lee, Hyun-Ah; Fei, Zhangjun; Wang, Liangsheng; Apel, Klaus

    2015-06-01

    Necrotrophic fungal pathogens produce toxic compounds that induce cell death in infected plants. Often, the primary targets of these toxins and the way a plant responds to them are not known. In the present work, the effect of tenuazonic acid (TeA), a non-host-specific toxin of Alternaria alternata, on Arabidopsis thaliana has been analysed. TeA blocks the QB -binding site at the acceptor side of photosystem II (PSII). As a result, charge recombination at the reaction centre (RC) of PSII is expected to enhance the formation of the excited triplet state of the RC chlorophyll that promotes generation of singlet oxygen ((1)O₂). (1)O₂ activates a signalling pathway that depends on the two EXECUTER (EX) proteins EX1 and EX2 and triggers a programmed cell death response. In seedlings treated with TeA at half-inhibition concentration (1)O₂-mediated and EX-dependent signalling is activated as indicated by the rapid and transient up-regulation of (1)O₂-responsive genes in wild type, and its suppression in ex1/ex2 mutants. Lesion formation occurs when seedlings are exposed to higher concentrations of TeA for a longer period of time. Under these conditions, the programmed cell death response triggered by (1)O₂-mediated and EX-dependent signalling is superimposed by other events that also contribute to lesion formation. © 2014 John Wiley & Sons Ltd.

  20. An ecological cost of plant defence : attractiveness of bitter cucumber plants to natural enemies of herbivores

    NARCIS (Netherlands)

    Agrawal, A.A.; Janssen, A.; Bruin, J.; Posthumus, M.A.; Sabelis, M.W.

    2002-01-01

    Plants produce defences that act directly on herbivores and indirectly via the attraction of natural enemies of herbivores. We examined the pleiotropic effects of direct chemical defence production on indirect defence employing near-isogenic varieties of cucumber plants (Cucumis sativus) that differ

  1. A proposed adhesin AoMad1 helps nematode-trapping fungus Arthrobotrys oligospora recognizing host signals for life-style switching.

    Science.gov (United States)

    Liang, Lianming; Shen, Renfei; Mo, Yuanyuan; Yang, Jinkui; Ji, Xinglai; Zhang, Ke-Qin

    2015-08-01

    The nematode-trapping fungus Arthrobotrys oligospora is an important natural enemy of nematodes. It can capture nematodes by producing a special mycelial structure called adhesive network or trap. The trap is also a signature of the fungus switching from the saprophytic lifestyle to the predacious lifestyle. At present, little is known about the mechanism of lifestyle switch in nematode-trapping fungi. Here we describe the effect of a cell wall protein called AoMad1 on lifestyle switch. The disruption of the AoMad1-encoding gene in A. oligospora resulted in the formation of more traps in the presence of nematodes. Interestingly, the mutant strain was more sensitive to certain nitrogen sources as trap inducers than the wild type strain. The microscopic examinations revealed that the AoMad1-deletion mutant lacked cell surface adhesive materials and the cell wall structures were more porous than wild-type strains. A great of genes were differentially expressed by transcriptomic analysis when trap formation was induced by sodium nitrate compared to the wild type strain, many of them were related to nitrogen metabolism, host-pathogen interaction and mycelia development. The results suggest that AoMad1 plays an important role in life style switching in A. oligospora. Copyright © 2015 Elsevier Inc. All rights reserved.

  2. Polymorphism at selected defence gene analogs (DGAs) of Musa ...

    African Journals Online (AJOL)

    One of the major diseases affecting banana is Sigatoka or leaf spot disease that comprises three species, Mycosphaerella fijiensis, Mycosphaerella musicola and Mycosphaerella eumusae. Plants have a large number of defence related genes which trigger a cascade of defense responses that halt the spread of pathogens.

  3. The Legacy of Daantjie Oosthuizen: Revisiting the Liberal Defence ...

    African Journals Online (AJOL)

    canberry

    The Legacy of Daantjie Oosthuizen: Revisiting the Liberal Defence of. Academic Freedom. André du Toit. De part ment of Po lit i cal Studies. Uni ver sity of Cape Town. Cape Town. Intro duction. The classic formu la tions of the liberal notion of academic freedom in the South. African context date from the period of the late ...

  4. Three intelligence methodologies for border defence and border ...

    African Journals Online (AJOL)

    Border defence is predominately against the armed forces of other states requiring tanks, aircraft and ships. Traditionally, border security includes the mission roles of immigration, crime, agriculture, finance, disease control and terrorism. Intelligence gathering and analysis using three methodologies - trends and patterns, ...

  5. Torpedo and countermeasures modelling in the Torpedo Defence System Testbed

    NARCIS (Netherlands)

    Benders, F.P.A.; Witberg, R.R.; H.J. Grootendorst, H.J.

    2002-01-01

    Several years ago, TNO-FEL started the development of the Torpedo Defence System Testbed (TDSTB) based on the TORpedo SIMulation (TORSIM) model and the Maritime Operations Simulation and Evaluation System (MOSES). MOSES provides the simulation and modelling environment for the evaluation and

  6. Alcohol misuse in patients attending a defence force general ...

    African Journals Online (AJOL)

    Aim: To determine the prevalence of alcohol misuse in adult patients attending a defence force general practice clinic. Design: Descriptive cross-sectional survey. Methods: The setting is a military sickbay situated in the Cape Town metropolitan area, South Africa. Participants included all adult patients (>=18 years) ...

  7. "Contributory intent" as a defence limiting delictual liability | Ahmed ...

    African Journals Online (AJOL)

    In terms of delictual liability, the term "fault" generally refers to the defendant's conduct, whereas "contributory fault" refers to the plaintiff's conduct. "Contributory intent" is a form of "contributory fault" and may apply as a defence limiting delictual liability within the ambit of the Apportionment of Damages Act 34 of 1956 ...

  8. Exploiting Modelling and Simulation in Support of Cyber Defence

    NARCIS (Netherlands)

    Klaver, M.H.A.; Boltjes, B.; Croom-Jonson, S.; Jonat, F.; Çankaya, Y.

    2014-01-01

    The rapidly evolving environment of Cyber threats against the NATO Alliance has necessitated a renewed focus on the development of Cyber Defence policy and capabilities. The NATO Modelling and Simulation Group is looking for ways to leverage Modelling and Simulation experience in research, analysis

  9. The South African Defence Force and Horse Mounted Infantry ...

    African Journals Online (AJOL)

    The South African Defence Force (SADF) made effective use of the horse mounted soldier in the Namibian Independence War or 'Border War', 1966 to 1989, in Namibia (South West African) and Angola, in a conflict usually depicted as a series of high profile mechanised infantry operations. Nevertheless, the legacy of the ...

  10. Safety Assessment Method of Flood Defences for Flow Sliding

    NARCIS (Netherlands)

    Van der Krogt, M.G.; Van den Ham, G.A.; Kok, M.

    2015-01-01

    Flow sliding of submerged slopes in front of dikes can affect the reliability of flood defences. The occurrence of flow sliding may result, sometimes with delay, in a failure mode and consequent flooding. The current safety assessment method for flow sliding does not consider the interaction between

  11. Suicide Prevention and Management in the SA National Defence ...

    African Journals Online (AJOL)

    Suicide Prevention and Management in the SA National Defence Force: A Psychological Discussion. ... Suicide can be a reaction in peacekeeping operations or conventional warfare, because the stressful nature of both types of operations can force military members to such a catastrophic end. This article focuses on the ...

  12. Standardization for Defence Procurement - European Handbook, recommendations Electromagnetic Environmental Effects

    NARCIS (Netherlands)

    Leferink, Frank Bernardus Johannes; Malabiau, R.

    2006-01-01

    The European Commission (EC) would like to improve the competitiveness of the European Defence Industry. The large number of (national) standards, more than 10.000, is recognised by EC as a major constraint and cost driver [1]. Electromagnetic Compatibility (EMC) and more generally Electromagnetic

  13. CSIR eNews: Defence peace safety and security

    CSIR Research Space (South Africa)

    CSIR

    2008-03-01

    Full Text Available At the CSIR, science and technology (S&T) is hard at work for a peaceful, safe and prosperous South Africa. The organisation has developed strong S&T capabilities through its associations with key players in defence, safety and security...

  14. CSIR eNews: Defence peace safety and security

    CSIR Research Space (South Africa)

    CSIR

    2009-08-01

    Full Text Available At the CSIR, science and technology (S&T) is a hard core at work for a peaceful, secured and prosperous South Africa. The organisation has developed strong S&T capabilities through its associations with key players in defence, safety and security...

  15. Briefing : Lessons learned from failures of flood defences

    NARCIS (Netherlands)

    Jonkman, S.N.; Schweckendiek, T.

    2015-01-01

    Failure of flood defences during extreme events can lead to enormous damage and loss of life. This paper presents lessons learned from investigations of flood events over recent years, including the 2005 flooding in New Orleans, USA, caused by hurricane Katrina. Based on these findings, new

  16. State Aid as a Defence for Public Authorities?

    DEFF Research Database (Denmark)

    Ølykke, Grith Skovgaard

    2016-01-01

    In the annotated judgment a public authority uses the existence of State aid as a defence in a legal action, where its contractual partner aimed to achieve damages and fulfilment of the contracts. The public authority claimed that the contracts were not on market terms, which also was the nationa...

  17. suicide prevention and management in the sa national defence force

    African Journals Online (AJOL)

    Rene

    DEFENCE FORCE: A PSYCHOLOGICAL. DISCUSSION. Rene Koopman and Gielie ..... includes depression, substance abuse, schizophrenia and many other mental illnesses, is the main cause for the ..... and mindset of soldiers seeking psychological help to assist them in dealing with the stressors they experience during ...

  18. Foreigners in the defence of South Africa | Jooste | Scientia Militaria ...

    African Journals Online (AJOL)

    Scientia Militaria: South African Journal of Military Studies. Journal Home · ABOUT · Advanced Search · Current Issue · Archives · Journal Home > Vol 16, No 2 (1986) >. Log in or Register to get access to full text downloads. Username, Password, Remember me, or Register. Foreigners in the defence of South Africa.

  19. Paradigm shifts, South African Defence Policy and the South African ...

    African Journals Online (AJOL)

    The South African paradigm that guided the pre-1994 Total Strategy defence outlook was later opposed and ousted by one that was more explanatory and embracing of the democratic features permeating and envisaged for South African society. This democratic imperative drove the dominant shift in the South African ...

  20. Plan ontogeny and chemical defence : older seedlings are better defended

    NARCIS (Netherlands)

    Elger, A.F.; Lemoine, D.G.; Fenner, M.; Hanley, M.E.

    2009-01-01

    Although patterns of seedling selection by herbivores are strongly influenced by plant age and the expression of anti-herbivore defence, it is unclear how these characteristics interact to influence seedling susceptibility to herbivory. We tracked ontogenetic changes in a range of secondary

  1. Cross Border EU Defence Industry Consolidation between Globalization and Europeanization

    DEFF Research Database (Denmark)

    Kluth, Michael Friederich

    The European Defence Industry is undergoing consolidation cutting across national borders. This is spurred by European Union policy initiatives and active encouragement by some national governments fearing a US-led global consolidation of the industry. The process in many ways proves challenging...

  2. Psychiatric, Psychological and “Witchcraft” Defences to Murder in ...

    African Journals Online (AJOL)

    Background: Expert psychiatric testimony may be relevant in certain instances of homicide especially murder. However, the exposure of most psychiatric trainees may be inadequate in relation to the range of psychological defences available to an offender accused of homicide. Aim: To describe the psychiatric and ...

  3. Interdepartmental Cooperation in Defence Issues and Strategic Intelligence

    Directory of Open Access Journals (Sweden)

    Nebojsa Nikolic

    2016-05-01

    Full Text Available The motivation for this paper comes from one successfully conducted empirical research about motivation of potential candidates to serve in the active reserve as a kind of military service which is recently introduced in the Serbian Army. The research team was faced with a set of problems related to the deadlines, resources and mandate issues. A solution was found in agile interdepartmental cooperation. Firstly, we started with identification of missing resources and mandates of our research team. Then, we investigated where we could find the missing issues. After that, we established lines for cooperation with other departments in the MoD. The clarity of interdepartmental communication and concretisation of demands and expectations were crucial for success. In the end we realized the full potential of interdepartmental cooperation and started to think about that phenomenon in the wider context of defence and security issues. We found some other examples of interdepartmental cooperation in earlier efforts of the defence sector reform, as well as some results in other armies. The paper presents strengths and opportunities of interdepartmental cooperation through temporary engaged working groups in the specific defence sector environment, as well as potential obstacles. In a wider aspect, interdepartmental cooperation in defence and security issues becomes more and more important because of new security challenges we are facing today.

  4. Probabilistic safety assessment of multi-functional flood defences

    NARCIS (Netherlands)

    Aguilar Lopez, Juan Pablo

    2016-01-01

    The state of the art of flood defence design and assessment shows that the most common adaptation measures for coping with the uncertainties associated with climate change often involve an increase in the size of these water-retaining structures. The shortage of habitable areas in the deltaic zones

  5. Polyphenol Stilbenes: Molecular Mechanisms of Defence against Oxidative Stress and Aging-Related Diseases

    Directory of Open Access Journals (Sweden)

    Mika Reinisalo

    2015-01-01

    Full Text Available Numerous studies have highlighted the key roles of oxidative stress and inflammation in aging-related diseases such as obesity, type 2 diabetes, age-related macular degeneration (AMD, and Alzheimer’s disease (AD. In aging cells, the natural antioxidant capacity decreases and the overall efficiency of reparative systems against cell damage becomes impaired. There is convincing data that stilbene compounds, a diverse group of natural defence phenolics, abundant in grapes, berries, and conifer bark waste, may confer a protective effect against aging-related diseases. This review highlights recent data helping to clarify the molecular mechanisms involved in the stilbene-mediated protection against oxidative stress. The impact of stilbenes on the nuclear factor-erythroid-2-related factor-2 (Nrf2 mediated cellular defence against oxidative stress as well as the potential roles of SQSTM1/p62 protein in Nrf2/Keap1 signaling and autophagy will be summarized. The therapeutic potential of stilbene compounds against the most common aging-related diseases is discussed.

  6. Polyphenol Stilbenes: Molecular Mechanisms of Defence against Oxidative Stress and Aging-Related Diseases.

    Science.gov (United States)

    Reinisalo, Mika; Kårlund, Anna; Koskela, Ali; Kaarniranta, Kai; Karjalainen, Reijo O

    2015-01-01

    Numerous studies have highlighted the key roles of oxidative stress and inflammation in aging-related diseases such as obesity, type 2 diabetes, age-related macular degeneration (AMD), and Alzheimer's disease (AD). In aging cells, the natural antioxidant capacity decreases and the overall efficiency of reparative systems against cell damage becomes impaired. There is convincing data that stilbene compounds, a diverse group of natural defence phenolics, abundant in grapes, berries, and conifer bark waste, may confer a protective effect against aging-related diseases. This review highlights recent data helping to clarify the molecular mechanisms involved in the stilbene-mediated protection against oxidative stress. The impact of stilbenes on the nuclear factor-erythroid-2-related factor-2 (Nrf2) mediated cellular defence against oxidative stress as well as the potential roles of SQSTM1/p62 protein in Nrf2/Keap1 signaling and autophagy will be summarized. The therapeutic potential of stilbene compounds against the most common aging-related diseases is discussed.

  7. Landscape settings as part of earth wall systems for defence

    Science.gov (United States)

    van den Ancker, Hanneke; Jungerius, Pieter Dirk

    2013-04-01

    Remnants of earth wall systems from different periods are preserved in many European countries. They were built for different functions, such as defence, demarcating ownership or keeping wild animals or cattle in or out a terrain, and often changed function over time. Earth walls date from a past in which man had limited access to man- and horsepower. In the case of defence systems, our ancestors made use of the landscape settings to improve the strength. The poster gives an overview of landscape settings used for this purpose, from prehistoric up to medieval age, for building round and linear earth wall defence systems. Round earth walls systems are found on: • High viewpoints along a river, often in combination with marshland at its feet, • Almost completely cut-off meanders of antecedent rivers. This natural setting offered an ideal defence. It allowed an almost 360 degree view and exposed the enemy for a long time when passing the river, while the steep slopes and narrow entrance made the hill fort difficult to access, • Islands in lakes, • Bordering a lake at one side, • Confluences of rivers, • Hills near the sea and a natural harbour with possibilities for defence, • High flat hill tops of medium size with steep sides. Of each situation examples are presented. Linear earth wall defence systems For linear defence earth walls no overview of landscape settings can be given, for lack of sufficient data. The Celtic, 10 m steep Beech Bottom Dyke earth wall system from around 20 A.D. connects two steeply incised river valleys. For building the Hadrian Wall (UK) the Romans made use of earth walls paralleling the steepest cuesta of the Cheviot hills. The Viking Danewerk (Ger), was built on push moraines and used the coastal marsh lands at their feet for defence. And the defence of the earth wall around the Velder (NL, probably 13th century) made use of the many small streams crossing this marshy coversand landscape, by diverting them into a canal

  8. NK Cell Receptor/H2-Dk–Dependent Host Resistance to Viral Infection Is Quantitatively Modulated by H2 q Inhibitory Signals

    Science.gov (United States)

    Fodil-Cornu, Nassima; Loredo-Osti, J. Concepción; Vidal, Silvia M.

    2011-01-01

    The cytomegalovirus resistance locus Cmv3 has been linked to an epistatic interaction between two loci: a Natural Killer (NK) cell receptor gene and the major histocompatibility complex class I (MHC-I) locus. To demonstrate the interaction between Cmv3 and H2k, we generated double congenic mice between MA/My and BALB.K mice and an F2 cross between FVB/N (H-2q) and BALB.K (H2k) mice, two strains susceptible to mouse cytomegalovirus (MCMV). Only mice expressing H2k in conjunction with Cmv3MA/My or Cmv3FVB were resistant to MCMV infection. Subsequently, an F3 cross was carried out between transgenic FVB/H2-Dk and MHC-I deficient mice in which only the progeny expressing Cmv3FVB and a single H2-Dk class-I molecule completely controlled MCMV viral loads. This phenotype was shown to be NK cell–dependent and associated with subsequent NK cell proliferation. Finally, we demonstrated that a number of H2q alleles influence the expression level of H2q molecules, but not intrinsic functional properties of NK cells; viral loads, however, were quantitatively proportional to the number of H2q alleles. Our results support a model in which H-2q molecules convey Ly49-dependent inhibitory signals that interfere with the action of H2-Dk on NK cell activation against MCMV infection. Thus, the integration of activating and inhibitory signals emanating from various MHC-I/NK cell receptor interactions regulates NK cell–mediated control of viral load. PMID:21533075

  9. NK cell receptor/H2-Dk-dependent host resistance to viral infection is quantitatively modulated by H2q inhibitory signals.

    Science.gov (United States)

    Fodil-Cornu, Nassima; Loredo-Osti, J Concepción; Vidal, Silvia M

    2011-04-01

    The cytomegalovirus resistance locus Cmv3 has been linked to an epistatic interaction between two loci: a Natural Killer (NK) cell receptor gene and the major histocompatibility complex class I (MHC-I) locus. To demonstrate the interaction between Cmv3 and H2(k), we generated double congenic mice between MA/My and BALB.K mice and an F(2) cross between FVB/N (H-2(q)) and BALB.K (H2(k)) mice, two strains susceptible to mouse cytomegalovirus (MCMV). Only mice expressing H2(k) in conjunction with Cmv3(MA/My) or Cmv3(FVB) were resistant to MCMV infection. Subsequently, an F(3) cross was carried out between transgenic FVB/H2-D(k) and MHC-I deficient mice in which only the progeny expressing Cmv3(FVB) and a single H2-D(k) class-I molecule completely controlled MCMV viral loads. This phenotype was shown to be NK cell-dependent and associated with subsequent NK cell proliferation. Finally, we demonstrated that a number of H2(q) alleles influence the expression level of H2(q) molecules, but not intrinsic functional properties of NK cells; viral loads, however, were quantitatively proportional to the number of H2(q) alleles. Our results support a model in which H-2(q) molecules convey Ly49-dependent inhibitory signals that interfere with the action of H2-D(k) on NK cell activation against MCMV infection. Thus, the integration of activating and inhibitory signals emanating from various MHC-I/NK cell receptor interactions regulates NK cell-mediated control of viral load.

  10. Pertussis Toxin Exploits Host Cell Signaling Pathways Induced by Meningitis-Causing E. coli K1-RS218 and Enhances Adherence of Monocytic THP-1 Cells to Human Cerebral Endothelial Cells.

    Science.gov (United States)

    Starost, Laura Julia; Karassek, Sascha; Sano, Yasuteru; Kanda, Takashi; Kim, Kwang Sik; Dobrindt, Ulrich; Rüter, Christian; Schmidt, Marcus Alexander

    2016-10-13

    Pertussis toxin (PTx), the major virulence factor of the whooping cough-causing bacterial pathogen Bordetella pertussis , permeabilizes the blood-brain barrier (BBB) in vitro and in vivo. Breaking barriers might promote translocation of meningitis-causing bacteria across the BBB, thereby facilitating infection. PTx activates several host cell signaling pathways exploited by the neonatal meningitis-causing Escherichia coli K1-RS218 for invasion and translocation across the BBB. Here, we investigated whether PTx and E. coli K1-RS218 exert similar effects on MAPK p38, NF-κB activation and transcription of downstream targets in human cerebral endothelial TY10 cells using qRT-PCR, Western blotting, and ELISA in combination with specific inhibitors. PTx and E. coli K1-RS218 activate MAPK p38, but only E. coli K1-RS218 activates the NF-κB pathway. mRNA and protein levels of p38 and NF-κB downstream targets including IL-6, IL-8, CxCL-1, CxCL-2 and ICAM-1 were increased. The p38 specific inhibitor SB203590 blocked PTx-enhanced activity, whereas E. coli K1-RS218's effects were inhibited by the NF-κB inhibitor Bay 11-7082. Further, we found that PTx enhances the adherence of human monocytic THP-1 cells to human cerebral endothelial TY10 cells, thereby contributing to enhanced translocation. These modulations of host cell signaling pathways by PTx and meningitis-causing E. coli support their contributions to pathogen and monocytic THP-1 cells translocation across the BBB.

  11. Genome-wide transcriptional changes and defence-related chemical profiling of rice in response to infestation by the rice striped stem borer Chilo suppressalis.

    Science.gov (United States)

    Zhou, Guoxin; Wang, Xia; Yan, Feng; Wang, Xia; Li, Ran; Cheng, Jiaan; Lou, Yonggen

    2011-09-01

    How rice defends itself against pathogen infection is well documented, but little is known about how it defends itself against herbivore attack. We measured changes in the transcriptome and chemical profile of rice when the plant is infested by the striped stem borer (SSB) Chilo suppressalis. Infestation by SSBs resulted in changes in the expression levels of 4545 rice genes; this number accounts for about 8% of the genome and is made up of 18 functional groups with broad functions. The largest group comprised genes involved in metabolism, followed by cellular transport, transcription and cellular signaling. Infestation by SSBs modulated many genes responsible for the biosynthesis of plant hormones and plant signaling. Jasmonic acid (JA), salicylic acid (SA) and ethylene were the major hormones that shaped the SSB-induced defence responses of rice. Many secondary signal transduction components, such as those involved in Ca²⁺ signaling and G-protein signaling, receptor and non-receptor protein kinases, and transcription factors were involved in the SSB-induced responses of rice. Photosynthesis and ATP synthesis from photophosphorylation were restricted by SSB feeding. In addition, SSB infestation induced the accumulation of defence compounds, including trypsin proteinase inhibitors (TrypPIs) and volatile organic compounds. These results demonstrate that SSB-induced defences required rice to reconfigure a wide variety of its metabolic, physiological and biochemical processes. Copyright © Physiologia Plantarum 2011.

  12. The gut microbiota plays a protective role in the host defence against pneumococcal pneumonia

    NARCIS (Netherlands)

    Schuijt, T.J.; Lankelma, J.M.; Scicluna, B.P.; Melo, e F.S.; Roelofs, J.J.; Boer, de J.D.; Hoogendijk, A.J.; Beer, de R.; Vos, de A.; Belzer, C.; Vos, de W.M.; Poll, van der T.; Wiersinga, W.J.

    2016-01-01

    OBJECTIVE: Pneumonia accounts for more deaths than any other infectious disease worldwide. The intestinal microbiota supports local mucosal immunity and is increasingly recognised as an important modulator of the systemic immune system. The precise role of the gut microbiota in bacterial pneumonia,

  13. The Tuberculous Granuloma: An Unsuccessful Host Defence Mechanism Providing a Safety Shelter for the Bacteria?

    Science.gov (United States)

    Silva Miranda, Mayra; Breiman, Adrien; Allain, Sophie; Deknuydt, Florence; Altare, Frederic

    2012-01-01

    One of the main features of the immune response to M. Tuberculosis is the formation of an organized structure called granuloma. It consists mainly in the recruitment at the infectious stage of macrophages, highly differentiated cells such as multinucleated giant cells, epithelioid cells and Foamy cells, all these cells being surrounded by a rim of lymphocytes. Although in the first instance the granuloma acts to constrain the infection, some bacilli can actually survive inside these structures for a long time in a dormant state. For some reasons, which are still unclear, the bacilli will reactivate in 10% of the latently infected individuals, escape the granuloma and spread throughout the body, thus giving rise to clinical disease, and are finally disseminated throughout the environment. In this review we examine the process leading to the formation of the granulomatous structures and the different cell types that have been shown to be part of this inflammatory reaction. We also discuss the different in vivo and in vitro models available to study this fascinating immune structure. PMID:22811737

  14. Emerging mosquito-borne viruses: transmission and modulation of host defence

    NARCIS (Netherlands)

    Fros, J.J.

    2015-01-01

    Summary Two highly pathogenic arthropod-borne (arbo)viruses, West Nile virus (WNV) and chikungunya virus (CHIKV), recently (re-)emerged in both Europe and the Americas. This resulted in large-scale epidemics of severe encephalitic and arthritogenic human disease, respectively. Both

  15. T Lymphocyte Immunity in Host Defence against Chlamydia trachomatis and Its Implication for Vaccine Development

    Directory of Open Access Journals (Sweden)

    X Yang

    1998-01-01

    Full Text Available Chlamydia trachomatis is an obligate intracellular bacterial pathogen that causes several significant human infectious diseases, including trachoma, urethritis, cervicitis and salpingitis, and is an important cofactor for transmission of human immunodeficiency virus. Until very recently, over three decades of research effort aimed at developing a C trachomatis vaccine had failed, due mainly to the lack of a precise understanding of the mechanisms for protective immunity. Although most studies concerning protective immunity to C trachomatis have focused on humoral immune responses, recent studies have clearly shown that T helper-1 (Th1-like CD4 T cell-mediated immune responses play the dominant role in protective immunity. These studies suggest a paradigm for chlamydial immunity and pathology based on the concept of heterogeneity (Th1/Th2 in CD4 T cell immune responses. This concept for chlamydial immunity offers a rational template on which to base renewed efforts for development of a chlamydial vaccine that targets the induction of cell-mediated Th1 immune responses.

  16. Co-transcriptomic Analysis by RNA Sequencing to Simultaneously Measure Regulated Gene Expression in Host and Bacterial Pathogen

    KAUST Repository

    Ravasi, Timothy

    2016-01-24

    Intramacrophage pathogens subvert antimicrobial defence pathways using various mechanisms, including the targeting of host TLR-mediated transcriptional responses. Conversely, TLR-inducible host defence mechanisms subject intramacrophage pathogens to stress, thus altering pathogen gene expression programs. Important biological insights can thus be gained through the analysis of gene expression changes in both the host and the pathogen during an infection. Traditionally, research methods have involved the use of qPCR, microarrays and/or RNA sequencing to identify transcriptional changes in either the host or the pathogen. Here we describe the application of RNA sequencing using samples obtained from in vitro infection assays to simultaneously quantify both host and bacterial pathogen gene expression changes, as well as general approaches that can be undertaken to interpret the RNA sequencing data that is generated. These methods can be used to provide insights into host TLR-regulated transcriptional responses to microbial challenge, as well as pathogen subversion mechanisms against such responses.

  17. Interpreting the impact of flood forecasts by combining policy analysis studies and flood defence

    Directory of Open Access Journals (Sweden)

    Slomp Robert

    2016-01-01

    Full Text Available Flood forecasting is necessary to save lives and reduce damages. Reducing damages is important to save livelihoods and to reduce the recovery time. Flood alerts should contain expected time of the event, location and extent of the event. A flood alert is not only one message but part of a rehearsed flow of information using multiple canals. First people have to accept the fact that there might be a threat and what the threat is about. People need a reference to understand the situation and be aware of possible measures they can take to assure their own safety and reduce damages. Information to the general public has to be consistent with the information used by emergency services and has to be very clear about consequences and context of possible measures (as shelter in place or preventive evacuation. Emergency services should monitor how the public is responding to adapt their communication en operation during a crisis. Flood warnings and emergency services are often coordinated by different government organisations. This is an extra handicap for having consistent information out on time for people to use. In an information based society, where everyone has twitter, email and a camera, public organisations may have to trust the public more and send out the correct information as it comes in. In the Netherlands Rijkswaterstaat, the National Water Authority and the National Public Works Department, is responsible for or involved in forecasting in case of floods, policy studies on flood risk, policy studies on maintenance, assessment and design of flood defences, elaborating rules and regulations for flood defences, advice on crisis management to the national government and for maintaining the main infrastructure in the Netherlands (high ways and water ways. The Water Management Center in the Netherlands (WMCN has developed a number of models to provide flood forecasts. WMCN is run for and by all managers of flood defences and is hosted by

  18. Systemic resistance and lipoxygenase-related defence response induced in tomato by Pseudomonas putida strain BTP1

    Directory of Open Access Journals (Sweden)

    Dommes Jacques

    2008-11-01

    Full Text Available Abstract Background Previous studies showed the ability of Pseudomonas putida strain BTP1 to promote induced systemic resistance (ISR in different host plants. Since ISR is long-lasting and not conducive for development of resistance of the targeted pathogen, this phenomenon can take part of disease control strategies. However, in spite of the numerous examples of ISR induced by PGPR in plants, only a few biochemical studies have associated the protective effect with specific host metabolic changes. Results In this study, we showed the protective effect of this bacterium in tomato against Botrytis cinerea. Following treatment by P. putida BTP1, analyses of acid-hydrolyzed leaf extracts showed an accumulation of antifungal material after pathogen infection. The fungitoxic compounds thus mainly accumulate as conjugates from which active aglycones may be liberated through the activity of hydrolytic enzymes. These results suggest that strain BTP1 can elicit systemic phytoalexin accumulation in tomato as one defence mechanism. On another hand, we have shown that key enzymes of the lipoxygenase pathway are stimulated in plants treated with the bacteria as compared with control plants. Interestingly, this stimulation is observed only after pathogen challenge in agreement with the priming concept almost invariably associated with the ISR phenomenon. Conclusion Through the demonstration of phytoalexin accumulation and LOX pathway stimulation in tomato, this work provides new insights into the diversity of defence mechanisms that are inducible by non-pathogenic bacteria in the context of ISR.

  19. Amphibian skin defences show variation in ability to inhibit growth of Batrachochytrium dendrobatidis isolates from the Global Panzootic Lineage.

    Science.gov (United States)

    Antwis, Rachael Ellen; Weldon, Ché

    2017-11-02

    The fungal pathogen Batrachochytrium dendrobatidis has caused declines and extinctions in hundreds of amphibian species across the world. Virulence varies among and within lineages; the Global Panzootic Lineage (GPL) is the most pathogenic, although there is also variation in lethality among GPL isolates. Amphibians have a number of defences against pathogens, and skin products including the microbiota and host peptides have considerable influence over disease progression. Here we demonstrate that the collective skin products (the mucosome) of two amphibian species show significant variation in their ability to inhibit different globally distributed isolates of GPL. This may in part explain the variation in disease susceptibility of hosts to different strains of B. dendrobatidis. More work is required to identify particular traits associated with mucosomes that confer broad-spectrum inhibition across GPL in order to facilitate the development of prophylaxis and/or treatments for chytridiomycosis in situ.

  20. Ceratocystis smalleyi colonization of bitternut hickkory and host responses in the xylem

    Science.gov (United States)

    J.-H. Park; J. Juzwik

    2014-01-01

    Colonization of Carya cordiformis sapwood by Ceratocystis smalleyi and subsequent host defence responses following artificial inoculation were investigated using anatomical and histological techniques. Hyphae of C. smalleyi were observed in all sapwood xylem features confirming the ability of the pathogen to...

  1. Mucin utilisation and host interactions of the novel intestinal microbe Akkermansia muciniphila

    NARCIS (Netherlands)

    Derrien, M.M.N.

    2007-01-01

    Keywords .Mucin, A. muciniphila , mucin degradation, molecular techniques, host responseMucins are the major organic components of the defence barrier, known as mucus, covering epithelial cells in many organs, including the entire gastrointestinal (GI)

  2. The evolutionary and coevolutionary consequences of defensive microbes for host-parasite interactions.

    Science.gov (United States)

    King, Kayla C; Bonsall, Michael B

    2017-08-14

    Animal and plant species can harbour microbes that provide them with protection against enemies. These beneficial microbes can be a significant component of host defence that complement or replaces a repertoire of immunity, but they can also be costly. Given their impact on host and parasite fitness, defensive microbes have the potential to influence host-parasite interactions on an evolutionary timescale. Using a phenotypic framework, we explore the evolutionary and coevolutionary dynamics of a host-parasite interaction in the presence of defensive microbes. We show that costs of host-defensive microbe systems are critical in determining whether a defensive microbe based system or an immune system provides better host protection investment. Partitioning the coevolutionary dynamics yields testable predictions. The density of defensive microbes influences the strength of selection resulting from host - defensive microbe - parasite coevolutionary interactions. We find that they lessen the negative effects of infection on hosts and reduce infectivity by directly competing with parasites. Defensive microbes might thus play a central role in host-parasite interactions, by outright replacing host-based defences, engaging in within-host competition with parasites, and ultimately driving tripartite coevolutionary dynamics.

  3. Life-history constraints in grassland plant species: a growth-defence trade-off is the norm

    Science.gov (United States)

    E.M. Lind; E.T. Borer; E.W. Seabloom; P.B. Adler; J.D. Bakker; D.M. Blumenthal; M. Crawley; K.F. Davies; J. Firn; D.S. Gruner; S. Harpole; Y. Hautier; H. Hillebrand; J.M.H. Knops; B.A. Melbourne; B. Mortensen; A.C. Risch; M. Schuetz; C.J. Stevens; P.D. Wragg

    2013-01-01

    Plant growth can be limited by resource acquisition and defence against consumers, leading to contrasting trade-off possibilities. The competition-defence hypothesis posits a trade-off between competitive ability and defence against enemies (e.g. herbivores and pathogens). The growth-defence hypothesis suggests that strong competitors for nutrients are also defended...

  4. Cathelicidin-like helminth defence molecules (HDMs: absence of cytotoxic, anti-microbial and anti-protozoan activities imply a specific adaptation to immune modulation.

    Directory of Open Access Journals (Sweden)

    Karine Thivierge

    Full Text Available Host defence peptides (HDPs are expressed throughout the animal and plant kingdoms. They have multifunctional roles in the defence against infectious agents of mammals, possessing both bactericidal and immune-modulatory activities. We have identified a novel family of molecules secreted by helminth parasites (helminth defence molecules; HDMs that exhibit similar structural and biochemical characteristics to the HDPs. Here, we have analyzed the functional activities of four HDMs derived from Schistosoma mansoni and Fasciola hepatica and compared them to human, mouse, bovine and sheep HDPs. Unlike the mammalian HDPs the helminth-derived HDMs show no antimicrobial activity and are non-cytotoxic to mammalian cells (macrophages and red blood cells. However, both the mammalian- and helminth-derived peptides suppress the activation of macrophages by microbial stimuli and alter the response of B cells to cytokine stimulation. Therefore, we hypothesise that HDMs represent a novel family of HDPs that evolved to regulate the immune responses of their mammalian hosts by retaining potent immune modulatory properties without causing deleterious cytotoxic effects.

  5. Inhibition of tumor vasculogenic mimicry and prolongation of host survival in highly aggressive gallbladder cancers by norcantharidin via blocking the ephrin type a receptor 2/focal adhesion kinase/paxillin signaling pathway.

    Directory of Open Access Journals (Sweden)

    Hui Wang

    Full Text Available Vasculogenic mimicry (VM is a newly-defined tumor microcirculation pattern in highly aggressive malignant tumors. We recently reported tumor growth and VM formation of gallbladder cancers through the contribution of the ephrin type a receptor 2 (EphA2/focal adhesion kinase (FAK/Paxillin signaling pathways. In this study, we further investigated the anti-VM activity of norcantharidin (NCTD as a VM inhibitor for gallbladder cancers and the underlying mechanisms. In vivo and in vitro experiments to determine the effects of NCTD on tumor growth, host survival, VM formation of GBC-SD nude mouse xenografts, and vasculogenic-like networks, malignant phenotypes i.e., proliferation, apoptosis, invasion and migration of GBC-SD cells. Expression of VM signaling-related markers EphA2, FAK and Paxillin in vivo and in vitro were examined by immunofluorescence, western blotting and real-time polymerase chain reaction (RT-PCR, respectively. The results showed that after treatment with NCTD, GBC-SD cells were unable to form VM structures when injecting into nude mouse, growth of the xenograft was inhibited and these observations were confirmed by facts that VM formation by three-dimensional (3-D matrix, proliferation, apoptosis, invasion, migration of GBC-SD cells were affected; and survival time of the xenograft mice was prolonged. Furthermore, expression of EphA2, FAK and Paxillin proteins/mRNAs of the xenografts was downregulated. Thus, we concluded that NCTD has potential anti-VM activity against human gallbladder cancers; one of the underlying mechanisms may be via blocking the EphA2/FAK/Paxillin signaling pathway.

  6. Harnessing ant defence at fruits reduces bruchid seed predation in a symbiotic ant–plant mutualism

    Science.gov (United States)

    Pringle, Elizabeth G.

    2014-01-01

    In horizontally transmitted mutualisms, mutualists disperse separately and reassemble in each generation with partners genetically unrelated to those in the previous generation. Because of this, there should be no selection on either partner to enhance the other's reproductive output directly. In symbiotic ant–plant mutualisms, myrmecophytic plants host defensive ant colonies, and ants defend the plants from herbivores. Plants and ants disperse separately, and, although ant defence can indirectly increase plant reproduction by reducing folivory, it is unclear whether ants can also directly increase plant reproduction by defending seeds. The neotropical tree Cordia alliodora hosts colonies of Azteca pittieri ants. The trees produce domatia where ants nest at stem nodes and also at the node between the peduncle and the rachides of the infloresence. Unlike the stem domatia, these reproductive domatia senesce after the tree fruits each year. In this study, I show that the tree's resident ant colony moves into these ephemeral reproductive domatia, where they tend honeydew-producing scale insects and patrol the nearby developing fruits. The presence of ants significantly reduced pre-dispersal seed predation by Amblycerus bruchid beetles, thereby directly increasing plant reproductive output. PMID:24807259

  7. Harnessing ant defence at fruits reduces bruchid seed predation in a symbiotic ant-plant mutualism.

    Science.gov (United States)

    Pringle, Elizabeth G

    2014-06-22

    In horizontally transmitted mutualisms, mutualists disperse separately and reassemble in each generation with partners genetically unrelated to those in the previous generation. Because of this, there should be no selection on either partner to enhance the other's reproductive output directly. In symbiotic ant-plant mutualisms, myrmecophytic plants host defensive ant colonies, and ants defend the plants from herbivores. Plants and ants disperse separately, and, although ant defence can indirectly increase plant reproduction by reducing folivory, it is unclear whether ants can also directly increase plant reproduction by defending seeds. The neotropical tree Cordia alliodora hosts colonies of Azteca pittieri ants. The trees produce domatia where ants nest at stem nodes and also at the node between the peduncle and the rachides of the infloresence. Unlike the stem domatia, these reproductive domatia senesce after the tree fruits each year. In this study, I show that the tree's resident ant colony moves into these ephemeral reproductive domatia, where they tend honeydew-producing scale insects and patrol the nearby developing fruits. The presence of ants significantly reduced pre-dispersal seed predation by Amblycerus bruchid beetles, thereby directly increasing plant reproductive output.

  8. Seasonal variation in the antifouling defence of the temperate brown alga Fucus vesiculosus.

    Science.gov (United States)

    Saha, Mahasweta; Wahl, Martin

    2013-01-01

    The important role of marine epibiotic biofilms in the interactions of the host with its environment has been acknowledged recently. Previous studies with the temperate brown macroalga Fucus vesiculosus have identified polar and non-polar compounds recovered from the algal surface that have the potential to control such biofilms. Furthermore, both the fouling pressure and the composition of the epibiotic bacterial communities on this macroalga varied seasonally. The extent to which this reflects a seasonal fluctuation of the fouling control mechanisms of the host is, however, unexplored in an ecological context. The present study investigated seasonal variation in the anti-settlement activity of surface extracts of F. vesiculosus against eight biofilm-forming bacteria isolated from rockweed-dominated habitats, including replication of two populations from two geographically distant sites. The anti-settlement activity at both sites was found to vary temporally, reaching a peak in summer/autumn. Anti-settlement activity also showed a consistent and strong difference between sites throughout the year. This study is the first to report temporal variation of antifouling defence originating from ecologically relevant surface-associated compounds.

  9. Nelson Mandela's defence: A psychological capital documentary analysis

    Directory of Open Access Journals (Sweden)

    Rene van Wyk

    2014-11-01

    Full Text Available This qualitative documentary analysis examines Nelson Mandela�s defence statement at the Rivonia Trial, Pretoria Supreme Court, on 20 April 1964. The defence document is analysed through the psychological capital lens, depicting themes that support the constructs of hope, efficacy, resilience and optimism. Psychological capital characteristics played a major role in the initial non-violent policies of negotiation. The inevitable establishment of Umkhonto we Sizwe followed, as a result of the increased restrictions and unwillingness of government to negotiate and collaborate. Mandela showed a determined spirit to unite the country. The discussion gives insight into Mandela�s authentic psychological capital leadership under difficult political and personal circumstances. Some implications are indicated in adopting Mandela�s psychological characteristics for personal reform.

  10. Characterisation of viral proteins that inhibit Toll-like receptor signal transduction.

    Science.gov (United States)

    Stack, Julianne; Bowie, Andrew G

    2009-01-01

    Toll-like receptor (TLR) signalling involves five TIR adapter proteins, which couple to downstream protein kinases that ultimately lead to the activation of transcription factors such as nuclear factor-kappaB (NF-kappaB) and members of the interferon regulatory factor (IRF) family. TLRs play a crucial role in host defence against invading microorganisms, and highlighting their importance in the immune system is the fact that TLRs are targeted by viral immune evasion strategies. Identifying the target host proteins of such viral inhibitors is very important because valuable insights into how host cells respond to infection may be obtained. Also, viral proteins may have potential as therapeutic agents. Luciferase reporter gene assays are a very useful tool for the analysis of TLR signalling pathways, as the effect of a putative viral inhibitor on a large amount of signals can be examined in one experiment. A basic reporter gene assay involves the transfection of cells with a luciferase reporter gene, along with an activating expression plasmid, with or without a plasmid expressing a viral inhibitor. Induction of a signalling pathway leads to luciferase protein expression, which is measured using a luminometer. Results from these assays can be informative for deciding which host proteins to test for interactions with a viral inhibitor. Successful assays for measuring protein-protein interactions include co-immunoprecipitations (Co-IPs) and glutathione-S-transferase (GST)-pulldowns. Co-IP experiments involve precipitating a protein out of a cell lysate using a specific antibody bound to Protein A/G sepharose. Additional molecules complexed to that protein are captured as well and can be detected by Western blot analysis. GST-pulldown experiments are similar in principle to Co-IPs, but a bait GST-fusion protein complexed to glutathione-sepharose (GSH) beads is used to pull down interaction partners instead of an antibody. Again, complexes recovered from the beads are

  11. Debugging and Logging Services for Defence Service Oriented Architectures

    Science.gov (United States)

    2012-02-01

    to facilitate the creation and maintenance of the most bug- free , reliable and stable information technology environment possible based on SOA using a...highly relevant to the Australian Defence context because of Defence’s need to integrate many legacy systems, to interoperate with other forces and...manifestation and what isn’t. Never throw away a debugging tool Storing related debugging tools, such as pro- grammer written test scripts, with the software

  12. A Review of Enterprise Architecture Use in Defence

    Science.gov (United States)

    2014-09-01

    Visio ™; and IBM’s enterprise architecting tool System Architect™. Similar to commercial EA frameworks such as the Zachman Framework and TOGAF, the...comprising office and graphic drawing tools (Microsoft Office desktop computing tools PowerPoint™, Word™, EXCEL™ and Visio ™), and specialist IBM EA...desktop computing “Common Operating Environment” (COE) in Defence. Visio ™ is also a CIOG approved software application and can be purchased through

  13. Sino-Japanese relations and ballistic missile defence

    OpenAIRE

    Hughes, Christopher W.

    2001-01-01

    Since December 1998, the Japanese government has formally committed itself to undertake cooperative technological research with the US into Ballistic Missile Defence (BMD). Japanese government policy-makers stress that the BMD project remains at present purely at the research stage, and that separate government decisions will be necessary before any progression towards the stages of development, production and deployment. Nevertheless, even at the research phase it is clear that both Japanese...

  14. Compromised Rat Testicular Antioxidant Defence System by Hypothyroidism before Puberty

    Directory of Open Access Journals (Sweden)

    Dipak K. Sahoo

    2012-01-01

    Full Text Available Altered thyroid function during early stages of development is known to affect adversely testicular growth, physiology, and antioxidant defence status at adulthood. The objective of the present study is to investigate the modulation of antioxidant defence status in neonatal persistent hypothyroid rats before their sexual maturation and also to identify the specific testicular cell populations vulnerable to degeneration during neonatal hypothyroidism in immature rats. Hypothyroidism was induced in neonates by feeding the lactating mother with 0.05% 6-n-propyl-2-thiouracil (PTU through the drinking water. From the day of parturition till weaning (25 day postpartum, the pups received PTU through mother's milk (or drinking water and then directly from drinking water containing PTU for the remaining period of experimentation. On the 31st day postpartum, the animals were sacrificed for the study. An altered antioxidant defence system marked by elevated SOD, CAT, and GR activities, with decreased GPx and GST activities were observed along with increased protein carbonylation, disturbed redox status in hypothyroid immature rat testis. This compromised testicular antioxidant status might have contributed to poor growth and development by affecting the spermatogenesis and steroidogenesis in rats before puberty as indicated by reduced germ cell number, complete absence of round spermatids, decreased seminiferous tubule diameter, and decreased testosterone level.

  15. Epigenetic variation in plant responses to defence hormones.

    Science.gov (United States)

    Latzel, Vít; Zhang, Yuanye; Karlsson Moritz, Kim; Fischer, Markus; Bossdorf, Oliver

    2012-11-01

    There is currently much speculation about the role of epigenetic variation as a determinant of heritable variation in ecologically important plant traits. However, we still know very little about the phenotypic consequences of epigenetic variation, in particular with regard to more complex traits related to biotic interactions. Here, a test was carried out to determine whether variation in DNA methylation alone can cause heritable variation in plant growth responses to jasmonic acid and salicylic acid, two key hormones involved in induction of plant defences against herbivores and pathogens. In order to be able to ascribe phenotypic differences to epigenetic variation, the hormone responses were studied of epigenetic recombinant inbred lines (epiRILs) of Arabidopsis thaliana - lines that are highly variable at the level of DNA methylation but nearly identical at the level of DNA sequence. Significant heritable variation was found among epiRILs both in the means of phenotypic traits, including growth rate, and in the degree to which these responded to treatment with jasmonic acid and salicylic acid. Moreover, there was a positive epigenetic correlation between the responses of different epiRILs to the two hormones, suggesting that plant responses to herbivore and pathogen attack may have a similar molecular epigenetic basis. This study demonstrates that epigenetic variation alone can cause heritable variation in, and thus potentially microevolution of, plant responses to defence hormones. This suggests that part of the variation of plant defences observed in natural populations may be due to underlying epigenetic, rather than entirely genetic, variation.

  16. Defence behaviour of reindeer in response to flying parasitic Diptera

    Directory of Open Access Journals (Sweden)

    Andrew J. Karter

    1989-06-01

    Full Text Available Similar defence behaviours were exhibited by a reindeer when experimentally exposed to three different species of tethered, flying parasitic Diptera, Cephenemyia trompe (Modeer, Hypoderma tarandi (L and Tabanid. Defencive behavioural responses appeared to be related to attack angle, and were not elicited by auditory stimuli. These observations raise questions about the validity of parasite species-specific defence responses in reindeer.Forsvars-adferd hos rein angrepet av flyvende, parasittiske diptera.Abstract in Norwegian / Sammendrag: Likeartet forsvars-adferd ble utvist av en rein som ble eksperimentelt utsatt for tre forskjellige arter av bundne, flyvende parasittiske diptera, Cephenemyia trompe (Modeer, Hypoderma tarandi (L og Tabanid. Den forsvarsmessige adferd syntes å ha sammenheng med parasittenes angreps-vinkel og ble ikke utløst av lydstimuli. Disse observasjoner reiser spørsmål om gyldigheten av parasittære artsspesifikke forsvarsreaksjoner hos rein.Poron puolustuskàyttàytyminen lentàvià kaksisiipisià (Diptera hyônteisià vastaan.Abstract in Finnish / Yhteenveto: Poro kàyttàytyi samalla tavalla kun se joutui tekemisiin kolmen kiinniolevan lentàvân kaksisiipisen hyônteisen: saulakan {Cephenemyia trompe Modeer, kurumupaarman {Hypoderma tarandi L ja parman kanssa. Puolustuskàyttàytyminen riippui hyônteisen làhestymiskulvàt kysymyksià lajispesifisen puolustuskàyttàytymisen esiintymisestà proolla hyônteisià vastaan.

  17. Transgenerational effects alter plant defence and resistance in nature.

    Science.gov (United States)

    Colicchio, J

    2017-04-01

    Trichomes, or leaf hairs, are epidermal extensions that take a variety of forms and perform many functions in plants, including herbivore defence. In this study, I document genetically determined variation, within-generation plasticity, and a direct role of trichomes in herbivore defence for Mimulus guttatus. After establishing the relationship between trichomes and herbivory, I test for transgenerational effects of wounding on trichome density and herbivore resistance. Patterns of interannual variation in herbivore density and the high cost of plant defence makes plant-herbivore interactions a system in which transgenerational phenotypic plasticity (TPP) is apt to evolve. Here, I demonstrate that parental damage alters offspring trichome density and herbivore resistance in nature. Moreover, this response varies between populations. This is among the first studies to demonstrate that TPP contributes to variation in nature, and also suggests that selection can modify TPP in response to local conditions. © 2017 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2017 European Society For Evolutionary Biology.

  18. Imposed glutathione-mediated redox switch modulates the tobacco wound-induced protein kinase and salicylic acid-induced protein kinase activation state and impacts on defence against Pseudomonas syringae

    Science.gov (United States)

    Matern, Sanja; Peskan-Berghoefer, Tatjana; Gromes, Roland; Kiesel, Rebecca Vazquez; Rausch, Thomas

    2015-01-01

    The role of the redox-active tripeptide glutathione in plant defence against pathogens has been studied extensively; however, the impact of changes in cellular glutathione redox potential on signalling processes during defence reactions has remained elusive. This study explored the impact of elevated glutathione content on the cytosolic redox potential and on early defence signalling at the level of mitogen-activated protein kinases (MAPKs), as well as on subsequent defence reactions, including changes in salicylic acid (SA) content, pathogenesis-related gene expression, callose depositions, and the hypersensitive response. Wild-type (WT) Nicotiana tabacum L. and transgenic high-glutathione lines (HGL) were transformed with the cytosol-targeted sensor GRX1-roGFP2 to monitor the cytosolic redox state. Surprisingly, HGLs displayed an oxidative shift in their cytosolic redox potential and an activation of the tobacco MAPKs wound-induced protein kinase (WIPK) and SA-induced protein kinase (SIPK). This activation occurred in the absence of any change in free SA content, but was accompanied by constitutively increased expression of several defence genes. Similarly, rapid activation of MAPKs could be induced in WT tobacco by exposure to either reduced or oxidized glutathione. When HGL plants were challenged with adapted or non-adapted Pseudomonas syringae pathovars, the cytosolic redox shift was further amplified and the defence response was markedly increased, showing a priming effect for SA and callose; however, the initial and transient hyperactivation of MAPK signalling was attenuated in HGLs. The results suggest that, in tobacco, MAPK and SA signalling may operate independently, both possibly being modulated by the glutathione redox potential. Possible mechanisms for redox-mediated MAPK activation are discussed. PMID:25628332

  19. Cyanogenesis of Wild Lima Bean (Phaseolus lunatus L.) Is an Efficient Direct Defence in Nature

    Science.gov (United States)

    Ballhorn, Daniel J.; Kautz, Stefanie; Heil, Martin; Hegeman, Adrian D.

    2009-01-01

    In natural systems plants face a plethora of antagonists and thus have evolved multiple defence strategies. Lima bean (Phaseolus lunatus L.) is a model plant for studies of inducible indirect anti-herbivore defences including the production of volatile organic compounds (VOCs) and extrafloral nectar (EFN). In contrast, studies on direct chemical defence mechanisms as crucial components of lima beans' defence syndrome under natural conditions are nonexistent. In this study, we focus on the cyanogenic potential (HCNp; concentration of cyanogenic glycosides) as a crucial parameter determining lima beans' cyanogenesis, i.e. the release of toxic hydrogen cyanide from preformed precursors. Quantitative variability of cyanogenesis in a natural population of wild lima bean in Mexico was significantly correlated with missing leaf area. Since existing correlations do not by necessity mean causal associations, the function of cyanogenesis as efficient plant defence was subsequently analysed in feeding trials. We used natural chrysomelid herbivores and clonal lima beans with known cyanogenic features produced from field-grown mother plants. We show that in addition to extensively investigated indirect defences, cyanogenesis has to be considered as an important direct defensive trait affecting lima beans' overall defence in nature. Our results indicate the general importance of analysing ‘multiple defence syndromes’ rather than single defence mechanisms in future functional analyses of plant defences. PMID:19424497

  20. Nitric oxide production by Biomphalaria glabrata haemocytes: effects of Schistosoma mansoni ESPs and regulation through the extracellular signal-regulated kinase pathway

    Directory of Open Access Journals (Sweden)

    Kirk Ruth S

    2009-04-01

    Full Text Available Abstract Background Schistosoma mansoni uses Biomphalaria glabrata as an intermediate host during its complex life cycle. In the snail, the parasite initially transforms from a miracidium into a mother sporocyst and during this process excretory-secretory products (ESPs are released. Nitric oxide (NO and its reactive intermediates play an important role in host defence responses against pathogens. This study therefore aimed to determine the effects of S. mansoni ESPs on NO production in defence cells (haemocytes from schistosome-susceptible and schistosome-resistant B. glabrata strains. As S. mansoni ESPs have previously been shown to inhibit extracellular signal-regulated kinase (ERK phosphorylation (activation in haemocytes from susceptible, but not resistant, B. glabrata the regulation of NO output by ERK in these cells was also investigated. Results Haemocytes from resistant snails challenged with S. mansoni ESPs (20 μg/ml over 5 h displayed an increase in NO production that was 3.3 times greater than that observed for unchallenged haemocytes; lower concentrations of ESPs (0.1–10 μg/ml did not significantly increase NO output. In contrast, haemocytes from susceptible snails showed no significant change in NO output following challenge with ESPs at any concentration used (0.1–20 μg/ml. Western blotting revealed that U0126 (1 μM or 10 μM blocked the phosphorylation (activation status of ERK in haemocytes from both snail strains. Inhibition of ERK signalling by U0126 attenuated considerably intracellular NO production in haemocytes from both susceptible and resistant B. glabrata strains, identifying ERK as a key regulator of NO output in these cells. Conclusion S. mansoni ESPs differentially influence intracellular NO levels in susceptible and resistant B. glabrata haemocytes, possibly through modulation of the ERK signalling pathway. Such effects might facilitate survival of S. mansoni in its intermediate host.

  1. AtWRKY22 promotes susceptibility to aphids and modulates salicylic acid and jasmonic acid signalling.

    Science.gov (United States)

    Kloth, Karen J; Wiegers, Gerrie L; Busscher-Lange, Jacqueline; van Haarst, Jan C; Kruijer, Willem; Bouwmeester, Harro J; Dicke, Marcel; Jongsma, Maarten A

    2016-05-01

    Aphids induce many transcriptional perturbations in their host plants, but the signalling cascades responsible and the effects on plant resistance are largely unknown. Through a genome-wide association (GWA) mapping study in Arabidopsis thaliana, we identified WRKY22 as a candidate gene associated with feeding behaviour of the green peach aphid, Myzus persicae The transcription factor WRKY22 is known to be involved in pathogen-triggered immunity, and WRKY22 gene expression has been shown to be induced by aphids. Assessment of aphid population development and feeding behaviour on knockout mutants and overexpression lines showed that WRKY22 increases susceptibility to M. persicae via a mesophyll-located mechanism. mRNA sequencing analysis of aphid-infested wrky22 knockout plants revealed the up-regulation of genes involved in salicylic acid (SA) signalling and down-regulation of genes involved in plant growth and cell-wall loosening. In addition, mechanostimulation of knockout plants by clip cages up-regulated jasmonic acid (JA)-responsive genes, resulting in substantial negative JA-SA crosstalk. Based on this and previous studies, WRKY22 is considered to modulate the interplay between the SA and JA pathways in response to a wide range of biotic and abiotic stimuli. Its induction by aphids and its role in suppressing SA and JA signalling make WRKY22 a potential target for aphids to manipulate host plant defences. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  2. AtWRKY22 promotes susceptibility to aphids and modulates salicylic acid and jasmonic acid signalling

    Science.gov (United States)

    Kloth, Karen J.; Wiegers, Gerrie L.; Busscher-Lange, Jacqueline; van Haarst, Jan C.; Kruijer, Willem; Bouwmeester, Harro J.; Dicke, Marcel; Jongsma, Maarten A.

    2016-01-01

    Aphids induce many transcriptional perturbations in their host plants, but the signalling cascades responsible and the effects on plant resistance are largely unknown. Through a genome-wide association (GWA) mapping study in Arabidopsis thaliana, we identified WRKY22 as a candidate gene associated with feeding behaviour of the green peach aphid, Myzus persicae. The transcription factor WRKY22 is known to be involved in pathogen-triggered immunity, and WRKY22 gene expression has been shown to be induced by aphids. Assessment of aphid population development and feeding behaviour on knockout mutants and overexpression lines showed that WRKY22 increases susceptibility to M. persicae via a mesophyll-located mechanism. mRNA sequencing analysis of aphid-infested wrky22 knockout plants revealed the up-regulation of genes involved in salicylic acid (SA) signalling and down-regulation of genes involved in plant growth and cell-wall loosening. In addition, mechanostimulation of knockout plants by clip cages up-regulated jasmonic acid (JA)-responsive genes, resulting in substantial negative JA–SA crosstalk. Based on this and previous studies, WRKY22 is considered to modulate the interplay between the SA and JA pathways in response to a wide range of biotic and abiotic stimuli. Its induction by aphids and its role in suppressing SA and JA signalling make WRKY22 a potential target for aphids to manipulate host plant defences. PMID:27107291

  3. Biosignatures of Pathogen and Host

    Energy Technology Data Exchange (ETDEWEB)

    Fitch, J P; Chromy, B A; Forde, C E; Garcia, E; Gardner, S N; Gu, P P; Kuczmarksi, T A; Melius, C F; McCutchen-Maloney, S L; Milanovich, F P; Motin, V L; Ott, L L; Quong, A A; Quong, J N; Rocco, J M; Slezak, T R; Sokhansanj, B A; Vitalis, E A; Zemla, A T; McCready, P M

    2002-08-27

    In information theory, a signature is characterized by the information content as well as noise statistics of the communication channel. Biosignatures have analogous properties. A biosignature can be associated with a particular attribute of a pathogen or a host. However, the signature may be lost in backgrounds of similar or even identical signals from other sources. In this paper, we highlight statistical and signal processing challenges associated with identifying good biosignatures for pathogens in host and other environments. In some cases it may be possible to identify useful signatures of pathogens through indirect but amplified signals from the host. Discovery of these signatures requires new approaches to modeling and data interpretation. For environmental biosignal collections, it is possible to use signal processing techniques from other applications (e.g., synthetic aperture radar) to track the natural progression of microbes over large areas. We also present a computer-assisted approach to identify unique nucleic-acid based microbial signatures. Finally, an understanding of host-pathogen interactions will result in better detectors as well as opportunities in vaccines and therapeutics.

  4. Zealous Advocates: The historical foundations of the adversarial criminal defence lawyer

    OpenAIRE

    Smith, T.

    2012-01-01

    The place of the criminal defence lawyer in the modern criminal justice system is a given; everysuspect and defendant expects full representation as a right. However, the defence lawyer appeared surprisingly late in the long and venerable history of the English and Welsh legal system. Notwithstanding the defence lawyer's role as advocate for the accused, this unique professional role involves a variety of duties and obligations. This article will focus on the historical development of these c...

  5. Battered women and the requirement of imminence in self-defence

    OpenAIRE

    Samantha Goosen

    2013-01-01

    Should the South African courts abolish the traditional imminence standard, something must be used to stand in its place. The identification of the various alternatives which have been suggested to replace imminence - most notably the establishment of the "reasonable woman standard" as advanced in the case of S v Engelbrecht 2005 (92) SACR 41 (W) - has moved the law of self-defence into the realm of subjectivity. The end result not only undermines self-defence as a justification defence, but ...

  6. Insect host location: a volatile situation.

    Science.gov (United States)

    Bruce, Toby J A; Wadhams, Lester J; Woodcock, Christine M

    2005-06-01

    Locating a host plant is crucial for a phytophagous (herbivorous) insect to fulfill its nutritional requirements and to find suitable oviposition sites. Insects can locate their hosts even though the host plants are often hidden among an array of other plants. Plant volatiles play an important role in this host-location process. The recognition of a host plant by these olfactory signals could occur by using either species-specific compounds or specific ratios of ubiquitous compounds. Currently, most studies favor the second scenario, with strong evidence that plant discrimination is due to central processing of olfactory signals by the insect, rather than their initial detection. Furthermore, paired or clustered olfactory receptor neurons might enable fine-scale spatio-temporal resolution of the complex signals encountered when ubiquitous compounds are used.

  7. Costs and benefits of chemical defence in the Red Alga Bonnemaisonia hamifera.

    Directory of Open Access Journals (Sweden)

    Göran M Nylund

    Full Text Available A number of studies have shown that the production of chemical defences is costly in terrestrial vascular plants. However, these studies do not necessarily reflect the costs of defence production in macroalgae, due to structural and functional differences between vascular plants and macroalgae. Using a specific culturing technique, we experimentally manipulated the defence production in the red alga Bonnemaisonia hamifera to examine if the defence is costly in terms of growth. Furthermore, we tested if the defence provides fitness benefits by reducing harmful bacterial colonisation of the alga. Costly defences should provide benefits to the producer in order to be maintained in natural populations, but such benefits through protection against harmful bacterial colonisation have rarely been documented in macroalgae. We found that algae with experimentally impaired defence production, but with an externally controlled epibacterial load, grew significantly better than algae with normal defence production. We also found that undefended algae exposed to a natural epibacterial load experienced a substantial reduction in growth and a 6-fold increase in cell bleaching, compared to controls. Thus, this study provides experimental evidence that chemical defence production in macroalgae is costly, but that the cost is outweighed by fitness benefits provided through protection against harmful bacterial colonisation.

  8. Defence mechanisms and coping strategies among caregivers in palliative care units.

    Science.gov (United States)

    Timmermann, Marie; Naziri, Despina; Etienne, Anne-Marie

    2009-01-01

    This article focuses on the relationship between defence mechanisms, coping strategies, palliative attitude, and the well-being of caregivers in palliative care units, who are confronted with death, suffering, and pain. They use many different defence mechanisms; however, studies linking their coping strategies and defence mechanisms are rare. This study uses a quantitative and qualitative design and is based on 18 caregivers (nurses) in 2 palliative care units in Belgium. Defence mechanisms are tested through a semi-structured interview, TAT, and DSQ-60. Coping strategies are evaluated through a semi-structured interview, COPE, and WCQ. To maximize our global approach, coping strategies and defence mechanisms are associated with measures of well-being and palliative attitude. We determined that defence mechanisms and coping strategies should not be seen as obstacles to professional practices. Palliative caregivers are more likely to adopt "mature" and "mental inhibition and compromise formation" defence mechanisms, as well as "emotion-focused" and "problem-focused" coping strategies. Defence mechanisms are more unconscious and constitute appropriate answers in extreme emotional situations. Coping strategies allow for more conscious processes of adaptation to the environment of palliative care units. This study shows positive relationships between different defence mechanisms and coping strategies, palliative attitudes, and caregivers' well-being. Institutions should improve the conditions for group exchange and for caregivers' individual introspection so that caregivers develop adapted capacities to cope with anxiety.

  9. Rapid metabolic profiling of Nicotiana tabacum defence responses against Phytophthora nicotianae using direct infrared laser desorption ionization mass spectrometry and principal component analysis.

    Science.gov (United States)

    Ibáñez, Alfredo J; Scharte, Judith; Bones, Philipp; Pirkl, Alexander; Meldau, Stefan; Baldwin, Ian T; Hillenkamp, Franz; Weis, Engelbert; Dreisewerd, Klaus

    2010-06-09

    Successful defence of tobacco plants against attack from the oomycete Phytophthora nicotianae includes a type of local programmed cell death called the hypersensitive response. Complex and not completely understood signaling processes are required to mediate the development of this defence in the infected tissue. Here, we demonstrate that different families of metabolites can be monitored in small pieces of infected, mechanically-stressed, and healthy tobacco leaves using direct infrared laser desorption ionization orthogonal time-of-flight mass spectrometry. The defence response was monitored for 1 - 9 hours post infection. Infrared laser desorption ionization orthogonal time-of-flight mass spectrometry allows rapid and simultaneous detection in both negative and positive ion mode of a wide range of naturally occurring primary and secondary metabolites. An unsupervised principal component analysis was employed to identify correlations between changes in metabolite expression (obtained at different times and sample treatment conditions) and the overall defence response.A one-dimensional projection of the principal components 1 and 2 obtained from positive ion mode spectra was used to generate a Biological Response Index (BRI). The BRI obtained for each sample treatment was compared with the number of dead cells found in the respective tissue. The high correlation between these two values suggested that the BRI provides a rapid assessment of the plant response against the pathogen infection. Evaluation of the loading plots of the principal components (1 and 2) reveals a correlation among three metabolic cascades and the defence response generated in infected leaves. Analysis of selected phytohormones by liquid chromatography electrospray ionization mass spectrometry verified our findings. The described methodology allows for rapid assessment of infection-specific changes in the plant metabolism, in particular of phenolics, alkaloids, oxylipins, and carbohydrates

  10. Rapid metabolic profiling of Nicotiana tabacum defence responses against Phytophthora nicotianae using direct infrared laser desorption ionization mass spectrometry and principal component analysis

    Directory of Open Access Journals (Sweden)

    Weis Engelbert

    2010-06-01

    Full Text Available Abstract Background Successful defence of tobacco plants against attack from the oomycete Phytophthora nicotianae includes a type of local programmed cell death called the hypersensitive response. Complex and not completely understood signaling processes are required to mediate the development of this defence in the infected tissue. Here, we demonstrate that different families of metabolites can be monitored in small pieces of infected, mechanically-stressed, and healthy tobacco leaves using direct infrared laser desorption ionization orthogonal time-of-flight mass spectrometry. The defence response was monitored for 1 - 9 hours post infection. Results Infrared laser desorption ionization orthogonal time-of-flight mass spectrometry allows rapid and simultaneous detection in both negative and positive ion mode of a wide range of naturally occurring primary and secondary metabolites. An unsupervised principal component analysis was employed to identify correlations between changes in metabolite expression (obtained at different times and sample treatment conditions and the overall defence response. A one-dimensional projection of the principal components 1 and 2 obtained from positive ion mode spectra was used to generate a Biological Response Index (BRI. The BRI obtained for each sample treatment was compared with the number of dead cells found in the respective tissue. The high correlation between these two values suggested that the BRI provides a rapid assessment of the plant response against the pathogen infection. Evaluation of the loading plots of the principal components (1 and 2 reveals a correlation among three metabolic cascades and the defence response generated in infected leaves. Analysis of selected phytohormones by liquid chromatography electrospray ionization mass spectrometry verified our findings. Conclusion The described methodology allows for rapid assessment of infection-specific changes in the plant metabolism, in particular

  11. A plant natriuretic peptide-like molecule of the pathogen Xanthomonas axonopodis pv. citri causes rapid changes in the proteome of its citrus host

    KAUST Repository

    Garavaglia, Betiana S

    2010-03-21

    Background: Plant natriuretic peptides (PNPs) belong to a novel class of peptidic signaling molecules that share some structural similarity to the N-terminal domain of expansins and affect physiological processes such as water and ion homeostasis at nano-molar concentrations. The citrus pathogen Xanthomonas axonopodis pv. citri possesses a PNP-like peptide (XacPNP) uniquely present in this bacteria. Previously we observed that the expression of XacPNP is induced upon infection and that lesions produced in leaves infected with a XacPNP deletion mutant were more necrotic and lead to earlier bacterial cell death, suggesting that the plant-like bacterial PNP enables the plant pathogen to modify host responses in order to create conditions favorable to its own survival.Results: Here we measured chlorophyll fluorescence parameters and water potential of citrus leaves infiltrated with recombinant purified XacPNP and demonstrate that the peptide improves the physiological conditions of the tissue. Importantly, the proteomic analysis revealed that these responses are mirrored by rapid changes in the host proteome that include the up-regulation of Rubisco activase, ATP synthase CF1 ? subunit, maturase K, and ?- and ?-tubulin.Conclusions: We demonstrate that XacPNP induces changes in host photosynthesis at the level of protein expression and in photosynthetic efficiency in particular. Our findings suggest that the biotrophic pathogen can use the plant-like hormone to modulate the host cellular environment and in particular host metabolism and that such modulations weaken host defence. 2010 Garavaglia et al; licensee BioMed Central Ltd.

  12. A plant natriuretic peptide-like molecule of the pathogen Xanthomonas axonopodis pv. citri causes rapid changes in the proteome of its citrus host

    Directory of Open Access Journals (Sweden)

    Ottado Jorgelina

    2010-03-01

    Full Text Available Abstract Background Plant natriuretic peptides (PNPs belong to a novel class of peptidic signaling molecules that share some structural similarity to the N-terminal domain of expansins and affect physiological processes such as water and ion homeostasis at nano-molar concentrations. The citrus pathogen Xanthomonas axonopodis pv. citri possesses a PNP-like peptide (XacPNP uniquely present in this bacteria. Previously we observed that the expression of XacPNP is induced upon infection and that lesions produced in leaves infected with a XacPNP deletion mutant were more necrotic and lead to earlier bacterial cell death, suggesting that the plant-like bacterial PNP enables the plant pathogen to modify host responses in order to create conditions favorable to its own survival. Results Here we measured chlorophyll fluorescence parameters and water potential of citrus leaves infiltrated with recombinant purified XacPNP and demonstrate that the peptide improves the physiological conditions of the tissue. Importantly, the proteomic analysis revealed that these responses are mirrored by rapid changes in the host proteome that include the up-regulation of Rubisco activase, ATP synthase CF1 α subunit, maturase K, and α- and β-tubulin. Conclusions We demonstrate that XacPNP induces changes in host photosynthesis at the level of protein expression and in photosynthetic efficiency in particular. Our findings suggest that the biotrophic pathogen can use the plant-like hormone to modulate the host cellular environment and in particular host metabolism and that such modulations weaken host defence.

  13. Locality versus globality in bacterial signalling: can local communication stabilize bacterial communities?

    Directory of Open Access Journals (Sweden)

    Bihary Dóra

    2010-04-01

    Full Text Available Abstract Background Microbial consortia are a major form of life; however their stability conditions are poorly understood and are often explained in terms of species-specific defence mechanisms (secretion of extracellular matrix, antimicrobial compounds, siderophores, etc.. Here we propose a hypothesis that the primarily local nature of intercellular signalling can be a general mechanism underlying the stability of many forms of microbial communities. Presentation of the hypothesis We propose that a large microbial community can be pictured as a theatre of spontaneously emerging, partially overlapping, locally recruited microcommunities whose members interact primarily among themselves, via secreted (signalling molecules or cell-cell contacts. We hypothesize that stability in an open environment relies on a predominantly local steady state of intercellular communication which ensures that i deleterious mutants or strains can be excluded by a localized collapse, while ii microcommunities harbouring useful traits can persist and/or spread even in the absence of specific protection mechanisms. Testing the hypothesis Some elements of this model can be tested experimentally by analyzing the behaviour of synthetic consortia composed of strains having well-defined communication systems and devoid of specific defence mechanisms. Supporting evidence can be obtained by in silico simulations. Implications of the hypothesis The hypothesis provides a framework for a systematic comparison of bacterial community behavior in open and closed environments. The model predicts that local signalling may enable multispecies communities to colonize open, structured environments. On the other hand, a confined niche or a host may be more likely to be colonized by a bacterial mono-species community, and local communication here provides a control against spontaneously arising cheaters, provided that survival depends on cooperation. Reviewers This article was reviewed by

  14. An Indirect Defence Trait Mediated through Egg-Induced Maize Volatiles from Neighbouring Plants.

    Directory of Open Access Journals (Sweden)

    Daniel M Mutyambai

    C. sesamiae parasitic wasps indicated that these parasitoids preferred volatiles from oviposited and neighbouring landrace plants compared to those from the control plants. This effect was absent in the standard commercial hybrid we tested. There was no HIPV induction and no difference in parasitoid attraction in neighbouring and control hybrid maize plants. These results show plant-plant signalling: 'Nyamula' maize plants emitting oviposition-induced volatiles attractive to the herbivore's natural enemies can induce this indirect defence trait in conspecific neighbouring undamaged maize plants. Maize plants growing in a field may thus benefit from this indirect defence through airborne signalling which may enhance the fitness of the volatile-emitting plant by increasing predation pressure on herbivores.

  15. Ethylene signalling and ethylene-targeted transcription factors are required to balance beneficial and nonbeneficial traits in the symbiosis between the endophytic fungus Piriformospora indica and Arabidopsis thaliana.

    Science.gov (United States)

    Camehl, Iris; Sherameti, Irena; Venus, Yvonne; Bethke, Gerit; Varma, Ajit; Lee, Justin; Oelmüller, Ralf

    2010-03-01

    *The endophytic fungus Piriformospora indica colonizes the roots of the model plant Arabidopsis thaliana and promotes its growth and seed production. The fungus can be cultivated in axenic culture without a host, and therefore this is an excellent system to investigate plant-fungus symbiosis. *The growth of etr1, ein2 and ein3/eil1 mutant plants was not promoted or even inhibited by the fungus; the plants produced less seeds and the roots were more colonized compared with the wild-type. This correlates with a mild activation of defence responses. The overexpression of ETHYLENE RESPONSE FACTOR1 constitutively activated defence responses, strongly reduced root colonization and abolished the benefits for the plants. *Piriformospora indica-mediated stimulation of growth and seed yield was not affected by jasmonic acid, and jasmonic acid-responsive promoter beta-glucuronidase gene constructs did not respond to the fungus in Arabidopsis roots. *We propose that ethylene signalling components and ethylene-targeted transcription factors are required to balance beneficial and nonbeneficial traits in the symbiosis. The results show that the restriction of fungal growth by ethylene signalling components is required for the beneficial interaction between the two symbionts.

  16. Involvement of salicylic acid, glutathione and protein S-thiolation in plant cell death-mediated defence response of Mesembryanthemum crystallinum against Botrytis cinerea.

    Science.gov (United States)

    Kuźniak, Elżbieta; Kaźmierczak, Andrzej; Wielanek, Marzena; Głowacki, Rafał; Kornas, Andrzej

    2013-02-01

    The response of Mesembryanthemum crystallinum plants performing C3 photosynthesis and crassulacean acid metabolism (CAM) to the non-host necrotrophic pathogen Botrytis cinerea was analyzed at the local and systemic levels. The induction of programmed cell death, lignin and callose deposition, changes in salicylic acid, glutathione and cysteinylglycine pools as well as the content of thiolated proteins were studied. The infected C3 and CAM plants exhibited hypersensitive-like defence response, however fluorescence staining with acridine orange and ethidium bromide revealed programmed cell death events in C3 plants only. The local immune response was not related to callose and lignin deposition. In the infected plants, salicylic acid, glutathione and cysteinylglycine, the first product of glutathione catabolism, as well as protein S-thiolation, predominantly S-glutathionylation, contributed to local defence at sites of inoculation. They (except protein thiolation) were also active in the establishment of systemic acclimation response monitored in the non-treated upper leaves. The extent to which they were involved in the local and systemic responses induced by B. cinerea differed in C3 and CAM plants. The accumulation of free salicylic acid, both in treated and upper leaves of the infected plants, was much more pronounced in CAM plants. The results have been discussed with respect to redox regulations in defence against necrotrophic pathogens and to stress acclimation. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

  17. Plasticity of the β-trefoil protein fold in the recognition and control of invertebrate predators and parasites by a fungal defence system.

    Directory of Open Access Journals (Sweden)

    Mario Schubert

    Full Text Available Discrimination between self and non-self is a prerequisite for any defence mechanism; in innate defence, this discrimination is often mediated by lectins recognizing non-self carbohydrate structures and so relies on an arsenal of host lectins with different specificities towards target organism carbohydrate structures. Recently, cytoplasmic lectins isolated from fungal fruiting bodies have been shown to play a role in the defence of multicellular fungi against predators and parasites. Here, we present a novel fruiting body lectin, CCL2, from the ink cap mushroom Coprinopsis cinerea. We demonstrate the toxicity of the lectin towards Caenorhabditis elegans and Drosophila melanogaster and present its NMR solution structure in complex with the trisaccharide, GlcNAcβ1,4[Fucα1,3]GlcNAc, to which it binds with high specificity and affinity in vitro. The structure reveals that the monomeric CCL2 adopts a β-trefoil fold and recognizes the trisaccharide by a single, topologically novel carbohydrate-binding site. Site-directed mutagenesis of CCL2 and identification of C. elegans mutants resistant to this lectin show that its nematotoxicity is mediated by binding to α1,3-fucosylated N-glycan core structures of nematode glycoproteins; feeding with fluorescently labeled CCL2 demonstrates that these target glycoproteins localize to the C. elegans intestine. Since the identified glycoepitope is characteristic for invertebrates but absent from fungi, our data show that the defence function of fruiting body lectins is based on the specific recognition of non-self carbohydrate structures. The trisaccharide specifically recognized by CCL2 is a key carbohydrate determinant of pollen and insect venom allergens implying this particular glycoepitope is targeted by both fungal defence and mammalian immune systems. In summary, our results demonstrate how the plasticity of a common protein fold can contribute to the recognition and control of antagonists by an innate

  18. Role of DetR in defence is critical for virulence of Xanthomonas oryzae pv. oryzae.

    Science.gov (United States)

    Nguyen, Minh-Phuong; Park, Jongchan; Cho, Man-Ho; Lee, Sang-Won

    2016-05-01

    Like other bacteria, Xanthomonas oryzae pv. oryzae (Xoo), the causal agent of bacterial leaf blight disease in rice, possesses intracellular signalling systems, known as two-component regulatory systems (TCSs), which regulate pathogenesis and biological processes. Completion of the genome sequences of three Xoo strains has facilitated the functional study of genes, including those of TCSs, but the biological functions of most Xoo TCSs have not yet been uncovered. To identify TCSs involved in Xoo pathogenesis, we generated knockout strains lacking response regulators (RRs, a cytoplasmic signalling component of the TCS) and examined the virulence of the RR knockout strains. This study presents a knockout strain (detR(-) ) lacking the PXO_04659 gene which shows dramatically reduced virulence relative to the wild-type. Our studies to elucidate detR function in Xoo pathogenesis revealed a reduction in extracellular polysaccharide (EPS), intolerance to reactive oxygen species (ROS) and deregulation of iron homeostasis in the detR(-) strain. Moreover, gene expression of regulatory factors, including other RRs and transcription factors (TFs), was altered in the absence of DetR protein, as determined by reverse transcription-polymerase chain reaction (RT-PCR) and/or real-time quantitative RT-PCR analyses. All evidence leads to the conclusion that DetR is essential for Xoo virulence through the regulation of the Xoo defence system including EPS synthesis, ROS detoxification and iron homeostasis, solely or cooperatively with other regulatory factors. © 2015 BSPP AND JOHN WILEY & SONS LTD.

  19. Microstructured fibres: a positive impact on defence technology?

    Science.gov (United States)

    O'Driscoll, E. J.; Watson, M. A.; Delmonte, T.; Petrovich, M. N.; Feng, X.; Flanagan, J. C.; Hayes, J. R.; Richardson, D. J.

    2006-09-01

    In this paper we seek to assess the potential impact of microstructured fibres for security and defence applications. Recent literature has presented results on using microstructured fibre for delivery of high power, high quality radiation and also on the use of microstructured fibre for broadband source generation. Whilst these two applications may appear contradictory to one another the inherent design flexibility of microstructured fibres allows fibres to be fabricated for the specific application requirements, either minimising (for delivery) or maximising (for broadband source generation) the nonlinear effects. In platform based laser applications such as infrared counter measures, remote sensing and laser directed-energy weapons, a suitable delivery fibre providing high power, high quality light delivery would allow a laser to be sited remotely from the sensor/device head. This opens up the possibility of several sensor/device types sharing the same multi-functional laser, thus reducing the complexity and hence the cost of such systems. For applications requiring broadband source characteristics, microstructured fibres can also offer advantages over conventional sources. By exploiting the nonlinear effects it is possible to realise a multifunctional source for applications such as active hyperspectral imaging, countermeasures, and biochemical sensing. These recent results suggest enormous potential for these novel fibre types to influence the next generation of photonic systems for security and defence applications. However, it is important to establish where the fibres can offer the greatest advantages and what research still needs to be done to drive the technology towards real platform solutions.

  20. Persistence of bat defence reactions in high Arctic moths (Lepidoptera).

    Science.gov (United States)

    Rydell, J; Roininen, H; Philip, K W

    2000-03-22

    We investigated the bat defence reactions of three species of moths (Gynaephora groenlandica, Gynaephora rossi (Lymantriidae) and Psychophora sabini (Geometridae)) in the Canadian Arctic archipelago. Since these moths inhabit the Arctic tundra and, therefore, are most probably spatially isolated from bats, their hearing and associated defensive reactions are probably useless and would therefore be expected to disappear with ongoing adaptation to Arctic conditions. When exposed to bat-like ultrasound (26 kHz and 110 dB sound pressure level root mean square at 1 m) flying male Gynaephora spp. always reacted defensively by rapidly reversing their flight course. They could hear the sound and reacted at least 15-25 m away. Psychophora sabini walking on a surface froze at distances of at least 5-7 m from the sound source. However, two out of three individuals of this species (all males) did not respond in any way to the sound while in flight. Hence, we found evidence of degeneration of bat defence reactions, i.e. adaptation to the bat-free environment, in P. sabini but not in Gynaephora spp. Some Arctic moths (Gynaephora spp.) still possess defensive reactions against bats, possibly because the selection pressure for the loss of the trait is such that it declines only very slowly (perhaps by genetic drift; and there may not have been enough time for the trait to disappear. One possible reason may be that Arctic moths have long generation times.

  1. Manic Defences in Contemporary Society. The Psychocultural Approach.

    Science.gov (United States)

    Rudan, Dusko; Jakovljevic, Miro; Marcinko, Darko

    2016-12-01

    The article discusses the impact of contemporary culture on the individual's personality. We used the "psychocultural" approach whose key feature is the amalgamation of theories and methods belonging to psychodynamic and psychosocial studies, as well as those used in the field of media and cultural studies. The idea of a potentially therapeutic effect of culture (therapy culture) can already been seen in Freud's and Lacan's texts, and it is often used in critical analyses of contemporary corporate culture, which is more or less developed in some parts of the world. In their criticisms, many contemporary authors emphasize that modern societies have a tendency towards the weakening of basic commitment, or lack thereof, to a social equivalent of Winnicott's concept of environmental provisions as an inalienable democratic right essential for human emotional and mental progress or emotional well-being. The article describes frequent resorting to the so-called manic defences that defensively distort, deny and obscure the awareness that a human being is not the omnipotent source of life, but instead depends on other human beings, and often tries to compensate for loss through various activities. The article describes excessive shopping as an activity that often serves as an attempt to find what was lost, i.e. to fill an emotional void. This solution (resorting to manic defences) is encouraged by contemporary culture, especially through promotional material (e.g. advertising). The main theses of this article are supported by quotations and data from world literature.

  2. The Xanthomonas campestris pv. vesicatoria Type-3 Effector XopB Inhibits Plant Defence Responses by Interfering with ROS Production.

    Directory of Open Access Journals (Sweden)

    Johannes Peter Roman Priller

    Full Text Available The bacterial pathogen Xanthomonas campestris pv. vesicatoria 85-10 (Xcv translocates about 30 type-3 effector proteins (T3Es into pepper plants (Capsicum annuum to suppress plant immune responses. Among them is XopB which interferes with PTI, ETI and sugar-mediated defence responses, but the underlying molecular mechanisms and direct targets are unknown so far. Here, we examined the XopB-mediated suppression of plant defence responses in more detail. Infection of susceptible pepper plants with Xcv lacking xopB resulted in delayed symptom development compared to Xcv wild type infection concomitant with an increased formation of salicylic acid (SA and expression of pathogenesis-related (PR genes. Expression of xopB in Arabidopsis thaliana promoted the growth of the virulent Pseudomonas syringae pv. tomato (Pst DC3000 strain. This was paralleled by a decreased SA-pool and a lower induction of SA-dependent PR gene expression. The expression pattern of early flg22-responsive marker genes indicated that MAPK signalling was not altered in the presence of XopB. However, XopB inhibited the flg22-triggered burst of reactive oxygen species (ROS. Consequently, the transcript accumulation of AtOXI1, a ROS-dependent marker gene, was reduced in xopB-expressing Arabidopsis plants as well as callose deposition. The lower ROS production correlated with a low level of basal and flg22-triggered expression of apoplastic peroxidases and the NADPH oxidase RBOHD. Conversely, deletion of xopB in Xcv caused a higher production of ROS in leaves of susceptible pepper plants. Together our results demonstrate that XopB modulates ROS responses and might thereby compromise plant defence.

  3. Defence against vertebrate herbivores trades off into architectural and low nutrient strategies amongst savanna Fabaceae species

    NARCIS (Netherlands)

    Tomlinson, K.W.; Langevelde, van F.; Ward, D.; Prins, H.H.T.; Bie, de S.; Vosman, B.; Sampaio, E.V.S.B.; Sterck, F.J.

    2016-01-01

    Herbivory contributes substantially to plant functional diversity and in ways that move far beyond direct defence trait patterns, as effective growth strategies under herbivory require modification of multiple functional traits that are indirectly related to defence. In order to understand how

  4. A laws of war review of contemporary land-based missile defence ...

    African Journals Online (AJOL)

    Automated precise guided missile defence has been around for some years, and is a modern-day mechanism used frequently since 2011 to defend against rocket attacks penetrating national airspace. Israel's automated Iron Dome Missile Defence System has intercepted over 1 000 rockets during two recent military ...

  5. Evaluating Jakarta's flood defence governance: The impact of political and institutional reforms

    NARCIS (Netherlands)

    I. Simanjuntak (Imelda); N. Frantzeskaki (Niki); B. Enserink (Bert); W. Ravesteijn (Wim)

    2012-01-01

    textabstractFlood defence management in Jakarta is a critical governmental activity, since Jakarta is a low-lying delta metropolis. Its protection against flooding is crucial for the continuing of economic activities. Despite the urgent need for action, the implementation of flood defences like the

  6. Time-dependent Reliability Analysis of Flood Defence Assets Using Generic Fragility Curve

    Directory of Open Access Journals (Sweden)

    Nepal Jaya

    2016-01-01

    Full Text Available Flood defence assets such as earth embankments comprise the vital part of linear flood defences in many countries including the UK and protect inland from flooding. The risks of flooding are likely to increase in the future due to increasing pressure on land use, increasing rainfall events and rising sea level caused by climate change also affect aging flood defence assets. Therefore, it is important that the flood defence assets are maintained at a high level of safety and serviceability. The high costs associated with preserving these deteriorating flood defence assets and the limited funds available for their maintenance require the development of systematic approaches to ensure the sustainable flood-risk management system. The integration of realistic deterioration measurement and reliabilitybased performance assessment techniques has tremendous potential for structural safety and economic feasibility of flood defence assets. Therefore, the need for reliability-based performance assessment is evident. However, investigations on time-dependent reliability analysis of flood defence assets are limited. This paper presents a novel approach for time-dependent reliability analysis of flood defence assets. In the analysis, time-dependent fragility curve is developed by using the state-based stochastic deterioration model. The applicability of the proposed approach is then demonstrated with a case study.

  7. Nutraceutical impact of fermented products on human immunity and self - defence mechanisms.

    OpenAIRE

    EIBLOVÁ, Veronika

    2008-01-01

    This bachelor thesis deals with nutraceutical impact of fermented products on human immunity and self - defence mechanisms. It presents probiotics, prebiotics and synbiotics and their supposed healthy influence on human immunity and self - defence mechanisms. We can also find here comparing of conclusions of the intervention on immunity of organisms and the status of cell immunity and the quality of life.

  8. Modelling the effects of a CBRN defence system using a Bayesian Belief Model

    NARCIS (Netherlands)

    Phillipson, F.; Bastings, I.C.L.; Vink, N.

    2015-01-01

    In this paper a Bayes model to quantify the effects of a passive CBRN defence system is presented. The model gives insight in the way of the mutual influence of all the elements of passive CBRN defence, by the use of detailed scenario analysis, sensitivity analysis and root cause analysis. This can

  9. NATO Guide for Judgement-Based Operational Analysis in Defence Decision Making : Executive Leaflet

    NARCIS (Netherlands)

    Wijnmalen, D.J.D.; et al

    2012-01-01

    Judgment plays an important role in all Operational Analysis (OA). NATO practitioners have determined that approaches in OA that are based on human judgement are increasingly critical to defence decision making. The purpose of the NATO Guide for Judgement-Based OA in Defence Decision Making is to

  10. NATO Guide for Judgement-Based Operational Analysis in Defence Decision Making : Client-Oriented Volume

    NARCIS (Netherlands)

    Wijnmalen, D.J.D.; et al

    2012-01-01

    Judgment plays an important role in all Operational Analysis (OA). NATO practitioners have determined that approaches in OA that are based on human judgement are increasingly critical to defence decision making. The purpose of the NATO Guide for Judgement-Based OA in Defence Decision Making is to

  11. Effects of light on direct and indirect defences against herbivores of young plants of Mallotus japonicus demonstrate a trade-off between two indirect defence traits.

    Science.gov (United States)

    Yamawo, Akira; Hada, Yoshio

    2010-07-01

    Although most studies on plant defence strategies have focused on a particular defence trait, some plant species develop multiple defence traits. To clarify the effects of light on the development of multiple defence traits, the production of direct and indirect defence traits of young plants of Mallotus japonicus were examined experimentally under different light conditions. The young plants were cultivated under three light conditions in the experimental field for 3 months from May to July. Numbers of ants and pearl bodies on leaves in July were examined. After cultivation, the plants were collected and the developments of trichomes and pellucid dots, and extrafloral nectaries (EFNs) on the leaves were examined. On plants without nectar-collecting insects, the size of EFNs and the volume of extrafloral nectar secreted from the EFNs were examined. Densities of trichomes and pellucid dots did not differ significantly among the plants under the different light conditions, suggesting that the chemical and physical defences function under both high and low light availability. The number of EFNs on the leaves did not differ significantly among the plants under the different light conditions, but there appeared to be a trade-off between the size of EFNs and the number of pearl bodies; the largest EFNs and the smallest number of pearl bodies were found under high light availability. EFN size was significantly correlated with the volume of extrafloral nectar secreted for 24 h. The number of ants on the plants was smaller under low light availability than under high and moderate light availability. These results suggest that direct defence traits function regardless of light conditions, but light conditions affected the development of indirect defence traits.

  12. The atypical resistance gene, RPW8, recruits components of basal defence for powdery mildew resistance in Arabidopsis.

    Science.gov (United States)

    Xiao, Shunyuan; Calis, Ozer; Patrick, Elaine; Zhang, Guangmin; Charoenwattana, Piyavadee; Muskett, Paul; Parker, Jane E; Turner, John G

    2005-04-01

    Genetic studies have identified a number of components of signal transduction pathways leading to plant disease resistance and the accompanying hypersensitive response (HR) following detection of pathogens by plant resistance (R) genes. In Arabidopsis, the majority of R proteins so far characterized belong to a plant superfamily that have a central nucleotide-binding site and C-terminal leucine-rich-repeats (NB-LRRs). Another much less prevalent class comprises RPW8.1 and RPW8.2, two related proteins that possess a putative N-terminal transmembrane domain and a coiled-coil motif, and confer broad-spectrum resistance to powdery mildew. Here we investigated whether RPW8.1 and RPW8.2 engage known pathway(s) for defence signalling. We show that RPW8.1 and RPW8.2 recruit, in addition to salicylic acid and EDS1, the other NB-LRR gene-signalling components PAD4, EDS5, NPR1 and SGT1b for activation of powdery mildew resistance and HR. In contrast, NDR1, RAR1 and PBS3 that are required for function of certain NB-LRR R genes, and COI1 and EIN2 that operate, respectively, in the jasmonic acid and ethylene signalling pathways, do not contribute to RPW8.1 and RPW8.2-mediated resistance. We further demonstrate that EDR1, a gene encoding a conserved MAPKK kinase, exerts negative regulation on HR cell death and powdery mildew resistance by limiting the transcriptional amplification of RPW8.1 and RPW8.2. Our results suggest that RPW8.1 and RPW8.2 stimulate a conserved basal defence pathway that is negatively regulated by EDR1.

  13. Defence Industrial Policies and Their Impact on Acquisition Outcomes: A Comparative Analysis of the United Kingdom and Australia

    Science.gov (United States)

    2012-09-01

    and industrial decisions;  where there is a mismatch between the level of activity our own plans (and export /civil opportunities) would support...for Defence, An independent report by Bernard Gray, October 2009 Hall, P and R. Wylie (2010), "Arms export controls and the proliferation of military...prompted by increasing pressure on defence budgets; consolidation of the UK defence industry; “ globalisation ” of UK defence companies & threat of exit

  14. Simple growth patterns can create complex trajectories for the ontogeny of constitutive chemical defences in seaweeds.

    Directory of Open Access Journals (Sweden)

    Nicholas A Paul

    Full Text Available All of the theory and most of the data on the ecology and evolution of chemical defences derive from terrestrial plants, which have considerable capacity for internal movement of resources. In contrast, most macroalgae--seaweeds--have no or very limited capacity for resource translocation, meaning that trade-offs between growth and defence, for example, should be localised rather than systemic. This may change the predictions of chemical defence theories for seaweeds. We developed a model that mimicked the simple growth pattern of the red seaweed Asparagopsis armata which is composed of repeating clusters of somatic cells and cells which contain deterrent secondary chemicals (gland cells. To do this we created a distinct growth curve for the somatic cells and another for the gland cells using empirical data. The somatic growth function was linked to the growth function for defence via differential equations modelling, which effectively generated a trade-off between growth and defence as these neighbouring cells develop. By treating growth and defence as separate functions we were also able to model a trade-off in growth of 2-3% under most circumstances. However, we found contrasting evidence for this trade-off in the empirical relationships between growth and defence, depending on the light level under which the alga was cultured. After developing a model that incorporated both branching and cell division rates, we formally demonstrated that positive correlations between growth and defence are predicted in many circumstances and also that allocation costs, if they exist, will be constrained by the intrinsic growth patterns of the seaweed. Growth patterns could therefore explain contrasting evidence for cost of constitutive chemical defence in many studies, highlighting the need to consider the fundamental biology and ontogeny of organisms when assessing the allocation theories for defence.

  15. Simple growth patterns can create complex trajectories for the ontogeny of constitutive chemical defences in seaweeds.

    Science.gov (United States)

    Paul, Nicholas A; Svensson, Carl Johan; de Nys, Rocky; Steinberg, Peter D

    2014-01-01

    All of the theory and most of the data on the ecology and evolution of chemical defences derive from terrestrial plants, which have considerable capacity for internal movement of resources. In contrast, most macroalgae--seaweeds--have no or very limited capacity for resource translocation, meaning that trade-offs between growth and defence, for example, should be localised rather than systemic. This may change the predictions of chemical defence theories for seaweeds. We developed a model that mimicked the simple growth pattern of the red seaweed Asparagopsis armata which is composed of repeating clusters of somatic cells and cells which contain deterrent secondary chemicals (gland cells). To do this we created a distinct growth curve for the somatic cells and another for the gland cells using empirical data. The somatic growth function was linked to the growth function for defence via differential equations modelling, which effectively generated a trade-off between growth and defence as these neighbouring cells develop. By treating growth and defence as separate functions we were also able to model a trade-off in growth of 2-3% under most circumstances. However, we found contrasting evidence for this trade-off in the empirical relationships between growth and defence, depending on the light level under which the alga was cultured. After developing a model that incorporated both branching and cell division rates, we formally demonstrated that positive correlations between growth and defence are predicted in many circumstances and also that allocation costs, if they exist, will be constrained by the intrinsic growth patterns of the seaweed. Growth patterns could therefore explain contrasting evidence for cost of constitutive chemical defence in many studies, highlighting the need to consider the fundamental biology and ontogeny of organisms when assessing the allocation theories for defence.

  16. Down-regulation of plant defence in a resident spider mite species and its effect upon con-and heterospecifics

    NARCIS (Netherlands)

    Godinho, D.P.; Janssen, A.; Dias, T.; Cruz, C.; Magalhães, S.

    2016-01-01

    Herbivorous spider mites occurring on tomato plants (Solanum lycopersicum L.) cope with plant defences in various manners: the invasive Tetranychus evansi reduces defences below constitutive levels, whereas several strains of T. urticae induce such defences and others suppress them. In the

  17. Infection success of Echinoparyphium aconiatum (Trematoda) in its snail host under high temperature: role of host resistance.

    Science.gov (United States)

    Leicht, Katja; Seppälä, Otto

    2014-04-21

    Extreme weather events such as summer heat waves become more frequent owing to global climate change and are predicted to alter disease dynamics. This is because high temperatures can reduce host immune function. Predicting the impact of climate change on host-parasite interactions is, however, difficult as temperature may also affect parasite infective stages and other host characteristics determining the outcome of interaction. Two experiments were conducted to investigate these phenomena in a Lymnaea stagnalis-Echinoparyphium aconiatum (Trematoda) interaction. In the first experiment, the effects of exposure of snails to experimental heat waves [maintenance at 25°C vs. 15°C (control)] with different durations (3 days, 7 days) on the infection success of parasite cercariae was examined. In the second experiment, the infection success was examined under similar conditions, while controlling for the possible temperature effects on cercariae and at least partly also for host physiological changes that take place rapidly compared to alterations in immune function (exposure to cercariae at intermediate 20°C). In the first experiment, increased infection success at 25°C was found independently of the duration of the heat wave. In the second experiment, increased infection success was found only in snails maintained at 25°C for 7 days, a treatment in which snail immune defence is known to be impaired. These results suggest that the effects of host resistance in determining overall parasite infection success can be overridden by effects of temperature on parasite transmission stages and/or alterations in other host traits than immune defence.

  18. Bacterial self-defence: how Escherichia coli evades serum killing.

    Science.gov (United States)

    Miajlovic, Helen; Smith, Stephen G

    2014-05-01

    The ability to survive the bactericidal action of serum is advantageous to extraintestinal pathogenic Escherichia coli that gain access to the bloodstream. Evasion of the innate defences present in serum, including complement and antimicrobial peptides, involves multiple factors. Serum resistance mechanisms utilized by E. coli include the production of protective extracellular polysaccharide capsules and expression of factors that inhibit or interfere with the complement cascade. Recent studies have also highlighted the importance of structural integrity of the cell envelope in serum survival. These survival strategies are outlined in this review with particular attention to novel findings and recent insights into well-established resistance mechanisms. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

  19. Modelling an infrared Man Portable Air Defence System

    Science.gov (United States)

    Birchenall, Richard P.; Richardson, Mark A.; Brian, Butters; Roy, Walmsley

    2010-09-01

    The global proliferation of shoulder launched IR Man Portable Air Defence Systems (ManPADS) has resulted in the existence of a serious threat to both civilian and military aircraft from terrorist attack. Some of the older generations of ManPADS can be defeated with modern countermeasures but even the most sophisticated protection still has vulnerabilities to the latest family of ManPADS. This paper describes the work undertaken by the authors to model a second generation ManPAD, based on the Russian SA-14, and assess the vulnerabilities of aircraft both with and without flare countermeasures from these systems. The conclusions are the results of over 11,000 simulated firings against targets of varying aspects, velocities and altitudes.

  20. Coevolutionary interactions between farmers and mafia induce host acceptance of avian brood parasites.

    Science.gov (United States)

    Abou Chakra, Maria; Hilbe, Christian; Traulsen, Arne

    2016-05-01

    Brood parasites exploit their host in order to increase their own fitness. Typically, this results in an arms race between parasite trickery and host defence. Thus, it is puzzling to observe hosts that accept parasitism without any resistance. The 'mafia' hypothesis suggests that these hosts accept parasitism to avoid retaliation. Retaliation has been shown to evolve when the hosts condition their response to mafia parasites, who use depredation as a targeted response to rejection. However, it is unclear if acceptance would also emerge when 'farming' parasites are present in the population. Farming parasites use depredation to synchronize the timing with the host, destroying mature clutches to force the host to re-nest. Herein, we develop an evolutionary model to analyse the interaction between depredatory parasites and their hosts. We show that coevolutionary cycles between farmers and mafia can still induce host acceptance of brood parasites. However, this equilibrium is unstable and in the long-run the dynamics of this host-parasite interaction exhibits strong oscillations: when farmers are the majority, accepters conditional to mafia (the host will reject first and only accept after retaliation by the parasite) have a higher fitness than unconditional accepters (the host always accepts parasitism). This leads to an increase in mafia parasites' fitness and in turn induce an optimal environment for accepter hosts.

  1. Interculturalism in the post-multicultural debate: a defence.

    Science.gov (United States)

    Zapata-Barrero, Ricard

    2017-01-01

    The main purpose of this article is to formulate a defence of the emerging intercultural policy paradigm for the benefit of those who are still somewhat reluctant to accept its proper place within the current migration-related diversity policy debate. My defence will take two main lines of argumentation: Firstly, I will state that the increasing intensity of the intercultural policy paradigm must be placed in the present-day post-multicultural period, which recognizes the strengths ​​of the multicultural policy paradigm but also the limits to its process for recognizing differences. The role played by the emerging national civic policy paradigm (a renovated version of assimilation), prioritizing duties before rights, will also be considered crucial to better contextualize interculturalism. Secondly, I will try to identify the main distinctive features of interculturalism, which legitimize its proper place within the diversity debate today. Without rejecting rights-based and duties-based policy approaches, interculturalism places more emphasis on a contacts-based policy approach, aimed at fostering communication and relationships among people from different backgrounds, including national citizens. This approach focuses on common bonds rather than differences. It also views diversity as an advantage and a resource, and centres its policy goals on community cohesion and reframing a common public culture that places diversity within rather than outside the so-called Unity. In reviewing the current literature and the origins of the intercultural policy paradigm, I restate its contribution towards resolving current trends in transnationalism, changing identities, superdiversity and the rise of populist anti-immigrant parties. These are issues the old multicultural project has struggled to deal with, which has provoked the current disillusionment. Lastly, I will propose a research avenue to further consolidate interculturalism as a distinctive and legitimate policy

  2. Silicon-based plant defences, tooth wear and voles.

    Science.gov (United States)

    Calandra, Ivan; Zub, Karol; Szafrańska, Paulina A; Zalewski, Andrzej; Merceron, Gildas

    2016-02-01

    Plant-herbivore interactions are hypothesized to drive vole population cycles through the grazing-induced production of phytoliths in leaves. Phytoliths act as mechanical defences because they deter herbivory and lower growth rates in mammals. However, how phytoliths impair herbivore performance is still unknown. Here, we tested whether the amount of phytoliths changes tooth wear patterns. If confirmed, abrasion from phytoliths could play a role in population crashes. We applied dental microwear texture analysis (DMTA) to laboratory and wild voles. Lab voles were fed two pelleted diets with differing amounts of silicon, which produced similar dental textures. This was most probably due to the loss of food mechanical properties through pelletization and/or the small difference in silicon concentration between diets. Wild voles were trapped in Poland during spring and summer, and every year across a population cycle. In spring, voles feed on silica-rich monocotyledons, while in the summer they also include silica-depleted dicotyledons. This was reflected in the results; the amount of silica therefore leaves a traceable record in the dental microwear texture of voles. Furthermore, voles from different phases of population cycles have different microwear textures. We tentatively propose that these differences result from grazing-induced phytolith concentrations. We hypothesize that the high amount of phytoliths in response to intense grazing in peak years may result in malocclusion and other dental abnormalities, which would explain how these silicon-based plant defences help provoke population crashes. DMTA could then be used to reconstruct vole population dynamics using teeth from pellets or palaeontological material. © 2016. Published by The Company of Biologists Ltd.

  3. H(2 enhances arabidopsis salt tolerance by manipulating ZAT10/12-mediated antioxidant defence and controlling sodium exclusion.

    Directory of Open Access Journals (Sweden)

    Yanjie Xie

    Full Text Available BACKGROUND: The metabolism of hydrogen gas (H(2 in bacteria and algae has been extensively studied for the interesting of developing H(2-based fuel. Recently, H(2 is recognized as a therapeutic antioxidant and activates several signalling pathways in clinical trials. However, underlying physiological roles and mechanisms of H(2 in plants as well as its signalling cascade remain unknown. METHODOLOGY/PRINCIPAL FINDINGS: In this report, histochemical, molecular, immunological and genetic approaches were applied to characterize the participation of H(2 in enhancing Arabidopsis salt tolerance. An increase of endogenous H(2 release was observed 6 hr after exposure to 150 mM NaCl. Arabidopsis pretreated with 50% H(2-saturated liquid medium, mimicking the induction of endogenous H(2 release when subsequently exposed to NaCl, effectively decreased salinity-induced growth inhibition. Further results showed that H(2 pretreatment modulated genes/proteins of zinc-finger transcription factor ZAT10/12 and related antioxidant defence enzymes, thus significantly counteracting the NaCl-induced reactive oxygen species (ROS overproduction and lipid peroxidation. Additionally, H(2 pretreatment maintained ion homeostasis by regulating the antiporters and H(+ pump responsible for Na(+ exclusion (in particular and compartmentation. Genetic evidence suggested that SOS1 and cAPX1 might be the target genes of H(2 signalling. CONCLUSIONS: Overall, our findings indicate that H(2 acts as a novel and cytoprotective regulator in coupling ZAT10/12-mediated antioxidant defence and maintenance of ion homeostasis in the improvement of Arabidopsis salt tolerance.

  4. Staphylococcus aureus pathogenesis in diverse host environments

    Science.gov (United States)

    Balasubramanian, Divya; Harper, Lamia; Shopsin, Bo; Torres, Victor J.

    2017-01-01

    Abstract Staphylococcus aureus is an eminent human pathogen that can colonize the human host and cause severe life-threatening illnesses. This bacterium can reside in and infect a wide range of host tissues, ranging from superficial surfaces like the skin to deeper tissues such as in the gastrointestinal tract, heart and bones. Due to its multifaceted lifestyle, S. aureus uses complex regulatory networks to sense diverse signals that enable it to adapt to different environments and modulate virulence. In this minireview, we explore well-characterized environmental and host cues that S. aureus responds to and describe how this pathogen modulates virulence in response to these signals. Lastly, we highlight therapeutic approaches undertaken by several groups to inhibit both signaling and the cognate regulators that sense and transmit these signals downstream. PMID:28104617

  5. Analysis of the Plant bos1 Mutant Highlights Necrosis as an Efficient Defence Mechanism during D. dadantii/Arabidospis thaliana Interaction

    Science.gov (United States)

    Patrit, Oriane; Simond-Côte, Elizabeth; Hermand, Victor; Van Gijsegem, Frédérique

    2011-01-01

    Dickeya dadantii is a broad host range phytopathogenic bacterium provoking soft rot disease on many plants including Arabidopsis. We showed that, after D. dadantii infection, the expression of the Arabidopsis BOS1 gene was specifically induced by the production of the bacterial PelB/C pectinases able to degrade pectin. This prompted us to analyze the interaction between the bos1 mutant and D. dadantii. The phenotype of the infected bos1 mutant is complex. Indeed, maceration symptoms occurred more rapidly in the bos1 mutant than in the wild type parent but at a later stage of infection, a necrosis developed around the inoculation site that provoked a halt in the progression of the maceration. This necrosis became systemic and spread throughout the whole plant, a phenotype reminiscent of that observed in some lesion mimic mutants. In accordance with the progression of maceration symptoms, bacterial population began to grow more rapidly in the bos1 mutant than in the wild type plant but, when necrosis appeared in the bos1 mutant, a reduction in bacterial population was observed. From the plant side, this complex interaction between D. dadantii and its host includes an early plant defence response that comprises reactive oxygen species (ROS) production accompanied by the reinforcement of the plant cell wall by protein cross-linking. At later timepoints, another plant defence is raised by the death of the plant cells surrounding the inoculation site. This plant cell death appears to constitute an efficient defence mechanism induced by D. dadantii during Arabidopsis infection. PMID:21533045

  6. Metabolomic assessment of induced and activated chemical defence in the invasive red alga Gracilaria vermiculophylla.

    Science.gov (United States)

    Nylund, Göran M; Weinberger, Florian; Rempt, Martin; Pohnert, Georg

    2011-01-01

    In comparison with terrestrial plants the mechanistic knowledge of chemical defences is poor for marine macroalgae. This restricts our understanding in the chemically mediated interactions that take place between algae and other organisms. Technical advances such as metabolomics, however, enable new approaches towards the characterisation of the chemically mediated interactions of organisms with their environment. We address defence responses in the red alga Gracilaria vermiculophylla using mass spectrometry based metabolomics in combination with bioassays. Being invasive in the north Atlantic this alga is likely to possess chemical defences according to the prediction that well-defended exotics are most likely to become successful invaders in systems dominated by generalist grazers, such as marine macroalgal communities. We investigated the effect of intense herbivore feeding and simulated herbivory by mechanical wounding of the algae. Both processes led to similar changes in the metabolic profile. Feeding experiments with the generalist isopod grazer Idotea baltica showed that mechanical wounding caused a significant increase in grazer resistance. Structure elucidation of the metabolites of which some were up-regulated more than 100 times in the wounded tissue, revealed known and novel eicosanoids as major components. Among these were prostaglandins, hydroxylated fatty acids and arachidonic acid derived conjugated lactones. Bioassays with pure metabolites showed that these eicosanoids are part of the innate defence system of macroalgae, similarly to animal systems. In accordance with an induced defence mechanism application of extracts from wounded tissue caused a significant increase in grazer resistance and the up-regulation of other pathways than in the activated defence. Thus, this study suggests that G. vermiculophylla chemically deters herbivory by two lines of defence, a rapid wound-activated process followed by a slower inducible defence. By unravelling

  7. Metabolomic assessment of induced and activated chemical defence in the invasive red alga Gracilaria vermiculophylla.

    Directory of Open Access Journals (Sweden)

    Göran M Nylund

    Full Text Available In comparison with terrestrial plants the mechanistic knowledge of chemical defences is poor for marine macroalgae. This restricts our understanding in the chemically mediated interactions that take place between algae and other organisms. Technical advances such as metabolomics, however, enable new approaches towards the characterisation of the chemically mediated interactions of organisms with their environment. We address defence responses in the red alga Gracilaria vermiculophylla using mass spectrometry based metabolomics in combination with bioassays. Being invasive in the north Atlantic this alga is likely to possess chemical defences according to the prediction that well-defended exotics are most likely to become successful invaders in systems dominated by generalist grazers, such as marine macroalgal communities. We investigated the effect of intense herbivore feeding and simulated herbivory by mechanical wounding of the algae. Both processes led to similar changes in the metabolic profile. Feeding experiments with the generalist isopod grazer Idotea baltica showed that mechanical wounding caused a significant increase in grazer resistance. Structure elucidation of the metabolites of which some were up-regulated more than 100 times in the wounded tissue, revealed known and novel eicosanoids as major components. Among these were prostaglandins, hydroxylated fatty acids and arachidonic acid derived conjugated lactones. Bioassays with pure metabolites showed that these eicosanoids are part of the innate defence system of macroalgae, similarly to animal systems. In accordance with an induced defence mechanism application of extracts from wounded tissue caused a significant increase in grazer resistance and the up-regulation of other pathways than in the activated defence. Thus, this study suggests that G. vermiculophylla chemically deters herbivory by two lines of defence, a rapid wound-activated process followed by a slower inducible

  8. Sugar homeostasis mediated by cell wall invertase GRAIN INCOMPLETE FILLING 1 (GIF1) plays a role in pre-existing and induced defence in rice.

    Science.gov (United States)

    Sun, Li; Yang, Dong-lei; Kong, Yu; Chen, Ying; Li, Xiao-Zun; Zeng, Long-Jun; Li, Qun; Wang, Er-Tao; He, Zu-Hua

    2014-02-01

    Sugar metabolism and sugar signalling are not only critical for plant growth and development, but are also important for stress responses. However, how sugar homeostasis is involved in plant defence against pathogen attack in the model crop rice remains largely unknown. In this study, we observed that the grains of gif1, a loss-of-function mutant of the cell wall invertase gene GRAIN INCOMPLETE FILLING 1 (GIF1), were hypersusceptible to postharvest fungal pathogens, with decreased levels of sugars and a thinner glume cell wall in comparison with the wild-type. Interestingly, constitutive expression of GIF1 enhanced resistance to both the rice bacterial pathogen Xanthomonas oryzae pv. oryzae and the fungal pathogen Magnaporthe oryzae. The GIF1-overexpressing (GIF1-OE) plants accumulated higher levels of glucose, fructose and sucrose compared with the wild-type plants. More importantly, higher levels of callose were deposited in GIF1-OE plants during pathogen infection. Moreover, the cell wall was much thicker in the infection sites of the GIF1-OE plants when compared with the wild-type plants. We also found that defence-related genes were constitutively activated in the GIF1-OE plants. Taken together, our study reveals that sugar homeostasis mediated by GIF1 plays an important role in constitutive and induced physical and chemical defence. © 2013 BSPP AND JOHN WILEY & SONS LTD.

  9. The resistance of sour orange to Citrus tristeza virus is mediated by both the salicylic acid and RNA silencing defence pathways.

    Science.gov (United States)

    Gómez-Muñoz, Neus; Velázquez, Karelia; Vives, María Carmen; Ruiz-Ruiz, Susana; Pina, José Antonio; Flores, Ricardo; Moreno, Pedro; Guerri, José

    2016-09-02

    Citrus tristeza virus (CTV) induces in the field the decline and death of citrus varieties grafted on sour orange (SO) rootstock, which has forced the use of alternative decline-tolerant rootstocks in affected countries, despite the highly desirable agronomic features of the SO rootstock. Declining citrus plants display phloem necrosis below the bud union. In addition, SO is minimally susceptible to CTV compared with other citrus varieties, suggesting partial resistance of SO to CTV. Here, by silencing different citrus genes with a Citrus leaf blotch virus-based vector, we have examined the implication of the RNA silencing and salicylic acid (SA) defence pathways in the resistance of SO to CTV. Silencing of the genes RDR1, NPR1 and DCL2/DCL4, associated with these defence pathways, enhanced virus spread and accumulation in SO plants in comparison with non-silenced controls, whereas silencing of the genes NPR3/NPR4, associated with the hypersensitive response, produced a slight decrease in CTV accumulation and reduced stunting of SO grafted on CTV-infected rough lemon plants. We also found that the CTV RNA silencing suppressors p20 and p23 also suppress the SA signalling defence, with the suppressor activity being higher in the most virulent isolates. © 2016 BSPP AND JOHN WILEY & SONS LTD.

  10. Abscisic acid deficiency increases defence responses against Myzus persicae in Arabidopsis.

    Science.gov (United States)

    Hillwig, Melissa S; Chiozza, Mariana; Casteel, Clare L; Lau, Siau Ting; Hohenstein, Jessica; Hernández, Enrique; Jander, Georg; MacIntosh, Gustavo C

    2016-02-01

    Comparison of Arabidopsis thaliana (Arabidopsis) gene expression induced by Myzus persicae (green peach aphid) feeding, aphid saliva infiltration and abscisic acid (ABA) treatment showed a significant positive correlation. In particular, ABA-regulated genes are over-represented among genes that are induced by M. persicae saliva infiltration into Arabidopsis leaves. This suggests that the induction of ABA-related gene expression could be an important component of the Arabidopsis-aphid interaction. Consistent with this hypothesis, M. persicae populations induced ABA production in wild-type plants. Furthermore, aphid populations were smaller on Arabidopsis aba1-1 mutants, which cannot synthesize ABA, and showed a significant preference for wild-type plants compared with the mutant. Total free amino acids, which play an important role in aphid nutrition, were not altered in the aba1-1 mutant line, but the levels of isoleucine (Ile) and tryptophan (Trp) were differentially affected by aphids in wild-type and mutant plants. Recently, indole glucosinolates have been shown to promote aphid resistance in Arabidopsis. In this study, 4-methoxyindol-3-ylmethylglucosinolate was more abundant in the aba1-1 mutant than in wild-type Arabidopsis, suggesting that the induction of ABA signals that decrease the accumulation of defence compounds may be beneficial for aphids. © 2015 BSPP AND JOHN WILEY & SONS LTD.

  11. The Strategic Failure of UK Defence Reform and What Still Needs to Be Done

    Science.gov (United States)

    2016-04-04

    acknowledgement in the NSS that an “ economic deficit is also a security deficit .”1 Acknowledging that the economy drives the budget for Defence is...required understanding the context of Defence Reform, the impact of strategic programs, the economic context, and the political relationship vis-à-vis...not go far enough to redress the £37.3 billion deficit in the Defence budget .4 At the time, the MoD faced a period of intense reform on the back of

  12. Toll-Like Receptor Signalling Is Not Involved in Platelet Response to Streptococcus pneumoniae In Vitro or In Vivo.

    Directory of Open Access Journals (Sweden)

    Sacha F de Stoppelaar

    Full Text Available Streptococcus (S. pneumoniae strains vary considerably in their ability to cause invasive disease in humans, which is at least in part determined by the capsular serotype. Platelets have been implicated as sentinel cells in the circulation for host defence. One of their utensils for this function is the expression of Toll-like receptors (TLRs. We here aimed to investigate platelet response to S. pneumoniae and a role for TLRs herein. Platelets were stimulated using four serotypes of S. pneumonia including an unencapsulated mutant strain. In vitro aggregation and flow cytometry assays were performed using blood of healthy volunteers, or blood of TLR knock out and WT mice. For in vivo pneumonia experiments, platelet specific Myd88 knockout (Plt-Myd88-/- mice were used. We found that platelet aggregation was induced by unencapsulated S. pneumoniae only. Whole blood incubation with all S. pneumoniae serotypes tested resulted in platelet degranulation and platelet-leukocyte complex formation. Platelet activation was TLR independent, as responses were not inhibited by TLR blocking antibodies, not induced by TLR agonists and were equally induced in wild-type and Tlr2-/-, Tlr4-/-, Tlr2/4-/-, Tlr9-/- and Myd88-/- blood. Plt-Myd88-/- and control mice displayed no differences in bacterial clearance or immune response to pneumonia by unencapsulated S. pneumoniae. In conclusion, S. pneumoniae activates platelets through a TLR-independent mechanism that is impeded by the bacterial capsule. Additionally, platelet MyD88-dependent TLR signalling is not involved in host defence to unencapsulated S. pneumoniae in vivo.

  13. Identification and characterization of novel defence and PCD signalling components in Arabidopsis

    DEFF Research Database (Denmark)

    Xie, Wenjun

    plants have homologues of SSD6, but none of these have been formally reported. Besides, there are two closely related proteins in Arabidopsis, SSH1 and SSH2, which were also studied in the project. The second gene, SSD12 was confirmed to encode PRLIP2. PRLIP2 contains a signature pentapeptide motif...

  14. Functional analysis of Arabidopsis immune-related MAPKs uncovers a role for MPK3 as negative regulator of inducible defences

    KAUST Repository

    Frei dit Frey, Nicolas

    2014-06-30

    Background Mitogen-activated protein kinases (MAPKs) are key regulators of immune responses in animals and plants. In Arabidopsis, perception of microbe-associated molecular patterns (MAMPs) activates the MAPKs MPK3, MPK4 and MPK6. Increasing information depicts the molecular events activated by MAMPs in plants, but the specific and cooperative contributions of the MAPKs in these signalling events are largely unclear. Results In this work, we analyse the behaviour of MPK3, MPK4 and MPK6 mutants in early and late immune responses triggered by the MAMP flg22 from bacterial flagellin. A genome-wide transcriptome analysis reveals that 36% of the flg22-upregulated genes and 68% of the flg22-downregulated genes are affected in at least one MAPK mutant. So far MPK4 was considered as a negative regulator of immunity, whereas MPK3 and MPK6 were believed to play partially redundant positive functions in defence. Our work reveals that MPK4 is required for the regulation of approximately 50% of flg22-induced genes and we identify a negative role for MPK3 in regulating defence gene expression, flg22-induced salicylic acid accumulation and disease resistance to Pseudomonas syringae. Among the MAPK-dependent genes, 27% of flg22-upregulated genes and 76% of flg22-downregulated genes require two or three MAPKs for their regulation. The flg22-induced MAPK activities are differentially regulated in MPK3 and MPK6 mutants, both in amplitude and duration, revealing a highly interdependent network. Conclusions These data reveal a new set of distinct functions for MPK3, MPK4 and MPK6 and indicate that the plant immune signalling network is choreographed through the interplay of these three interwoven MAPK pathways.

  15. Potato virus Y infection hinders potato defence response and renders plants more vulnerable to Colorado potato beetle attack.

    Science.gov (United States)

    Petek, Marko; Rotter, Ana; Kogovšek, Polona; Baebler, Spela; Mithöfer, Axel; Gruden, Kristina

    2014-11-01

    In the field, plants are challenged by more than one biotic stressor at the same time. In this study, the molecular interactions between potato (Solanum tuberosum L.), Colorado potato beetle (Leptinotarsa decemlineata Say; CPB) and Potato virus Y(NTN) (PVY(NTN) ) were investigated through analyses of gene expression in the potato leaves and the gut of the CPB larvae, and of the release of potato volatile compounds. CPB larval growth was enhanced when reared on secondary PVY(NTN) -infected plants, which was linked to decreased accumulation of transcripts associated with the antinutritional properties of potato. In PVY(NTN) -infected plants, ethylene signalling pathway induction and induction of auxin response transcription factors were attenuated, while no differences were observed in jasmonic acid (JA) signalling pathway. Similarly to rearing on virus-infected plants, CPB larvae gained more weight when reared on plants silenced in JA receptor gene (coi1). Although herbivore-induced defence mechanism is regulated predominantly by JA, response in coi1-silenced plants only partially corresponded to the one observed in PVY(NTN) -infected plants, confirming the role of other plant hormones in modulating this response. The release of β-barbatene and benzyl alcohol was different in healthy and PVY(NTN) -infected plants before CPB larvae infestation, implicating the importance of PVY(NTN) infection in plant communication with its environment. This was reflected in gene expression profiles of neighbouring plants showing different degree of defence response. This study thus contributes to our understanding of plant responses in agro-ecosystems. © 2014 The Authors. Molecular Ecology Published by John Wiley & Sons Ltd.

  16. Are Aristolochic Acids Responsible for the Chemical Defence of Aposematic Larvae of Battus polydamas (L.) (Lepidoptera: Papilionidae)?

    Science.gov (United States)

    Morais, A B B; Brown, K S; Stanton, M A; Massuda, K F; Trigo, J R

    2013-12-01

    Aristolochic acids (AAs) are thought to be responsible for the chemical protection of the aposematic larvae Battus polydamas (L.) (Papilionidae: Troidini) against predators. These compounds are sequestered by larvae from their Aristolochia (Aristolochiaceae) host plants. Studying the role of the chemical protection of the second and fifth instars of B. polydamas against potential predators, we found that the consumption of larvae by the carpenter ant Camponotus crassus Mayr and young chicks Gallus gallus domesticus was dependent on larval developmental stage. Second instars were more preyed upon than fifth instars; however, the assassin bug Montina confusa Stål was not deterred by chemical defences of the fifth instar B. polydamas. Laboratory bioassays with carpenter ants and young chicks using palatable baits topically treated with a pure commercial mixture of AAs I and AAs II in concentrations up to 100 times those previously found in B. polydamas larvae showed no activity. Similar results were found in field bioassays, where palatable baits treated as above were exposed to the guild of predators that attack B. polydamas larvae and were also consumed irrespective of the commercial AA concentration used. These results suggest that the mixture of AAs I and AAs II have no defensive role against predators, at least against those investigated in the present work. Other compounds present in Aristolochia host plants such as O-glycosylated AAs; benzylisoquinoline alkaloids; and mono-, sesqui-, di-, and triterpenes, which can be sequestered by Troidini, could act as deterrents against predators.

  17. The evolution of plant chemical defence - new roles for hydroxynitrile glucosides in Lotus japonicus

    DEFF Research Database (Denmark)

    Knudsen, Camilla

    types of adaptations enable plants to avoid the potential lethal effects of their own defence compounds. These adaptations include detoxification and stabilization by glycosylation and the genomic clustering of biosynthetic pathway genes. These two types are the main focus of this PhD thesis......Plants are sessile organisms well-known to produce a vast array of chemical compounds of which many are used in chemical defence against herbivores and pathogens. The biosynthesis of these plant chemical defence compounds poses a considerable risk of self-toxicity for the plant itself. Several...... on hydroxynitrile glucoside metabolism in the legume model plant Lotus japonicus. Lotus japonicus produces both cyanogenic and non-cyanogenic hydroxynitrile glucosides as chemical defence compounds. The cyanogenic glucosides linamarin and lotaustralin are stored in the cell vacuole as inactive glycosides and, upon...

  18. Lepidopteran defence droplets - a composite physical and chemical weapon against potential predators

    DEFF Research Database (Denmark)

    Pentzold, Stefan; Zagrobelny, Mika; Khakimov, Bekzod

    2016-01-01

    Insects often release noxious substances for their defence. Larvae of Zygaena filipendulae (Lepidoptera) secrete viscous and cyanogenic glucoside-containing droplets, whose effectiveness was associated with their physical and chemical properties. The droplets glued mandibles and legs of potential...

  19. Dynamic Plant-Plant-Herbivore Interactions Govern Plant Growth-Defence Integration.

    Science.gov (United States)

    de Vries, Jorad; Evers, Jochem B; Poelman, Erik H

    2017-04-01

    Plants downregulate their defences against insect herbivores upon impending competition for light. This has long been considered a resource trade-off, but recent advances in plant physiology and ecology suggest this mechanism is more complex. Here we propose that to understand why plants regulate and balance growth and defence, the complex dynamics in plant-plant competition and plant-herbivore interactions needs to be considered. Induced growth-defence responses affect plant competition and herbivore colonisation in space and time, which has consequences for the adaptive value of these responses. Assessing these complex interactions strongly benefits from advanced modelling tools that can model multitrophic interactions in space and time. Such an exercise will allow a critical re-evaluation why and how plants integrate defence and competition for light. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Structural host-microbiota interaction networks.

    Science.gov (United States)

    Guven-Maiorov, Emine; Tsai, Chung-Jung; Nussinov, Ruth

    2017-10-01

    Hundreds of different species colonize multicellular organisms making them "metaorganisms". A growing body of data supports the role of microbiota in health and in disease. Grasping the principles of host-microbiota interactions (HMIs) at the molecular level is important since it may provide insights into the mechanisms of infections. The crosstalk between the host and the microbiota may help resolve puzzling questions such as how a microorganism can contribute to both health and disease. Integrated superorganism networks that consider host and microbiota as a whole-may uncover their code, clarifying perhaps the most fundamental question: how they modulate immune surveillance. Within this framework, structural HMI networks can uniquely identify potential microbial effectors that target distinct host nodes or interfere with endogenous host interactions, as well as how mutations on either host or microbial proteins affect the interaction. Furthermore, structural HMIs can help identify master host cell regulator nodes and modules whose tweaking by the microbes promote aberrant activity. Collectively, these data can delineate pathogenic mechanisms and thereby help maximize beneficial therapeutics. To date, challenges in experimental techniques limit large-scale characterization of HMIs. Here we highlight an area in its infancy which we believe will increasingly engage the computational community: predicting interactions across kingdoms, and mapping these on the host cellular networks to figure out how commensal and pathogenic microbiota modulate the host signaling and broadly cross-species consequences.

  1. Differences in household attitudes on food defence and food safety: an international comparison

    OpenAIRE

    Stinson, Thomas F.; Albisu Aguado, Luis Miguel; Canavari, Maurizio; Larson, Ronald; Gracia Royo, Azucena

    2011-01-01

    This paper reports results from a large, six-nation, internet-based survey of consumer attitudes toward food safety and food defence administered during the fall of 2008. Responses were obtained from separate samples of approximately 1,000 each in Germany, Italy, Japan, Spain, the UK, and the USA. Food defence was generally a greater concern, and respondents were less confident that their food supply was well protected against terrorist attack than they were that their food was safe from c...

  2. Some practical examples of defence in depth analysis for category IV gamma irradiators

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues Junior, Ary de Araujo, E-mail: aryarj@ig.com.br [Universidade Estadual de Maringa (UEM), Maringa, PR (Brazil). Dept. de Fisica

    2014-07-01

    The Defence in Depth concept provides a major contribution to the safety philosophy of irradiation facilities. But problems occur when somebody tries to understand or analyse a safety system or develop a new one because there is a lack of practical examples in Safety Series 107 or other IAEA (International Atomic Energy Agency) publications for irradiation facilities. This paper tries to fill this lack of information by providing a series of practical examples and explanations about Defence in Depth concepts. (author)

  3. UK Defence Acquisition Process for NEC: Transaction Governance within an Integrated Project Team

    Science.gov (United States)

    2009-04-22

    MoD has become more conscious of the need to obtain better value for money in equipment procurement. As a result, it has become a more demanding...contractors would abide by the “ value for money ” principles. Target Cost Incentive agreements were predominantly used for non-competitive defence contracts...defence procurement was failing to achieve efficiency (despite the changes mentioned above): poor value for money ; poor project management; and poor

  4. Transformation or Stagnation? The South African Defence Industry in the early 21st Century

    OpenAIRE

    Paul Dunne; Richard Haines

    2005-01-01

    In post-Apartheid South Africa, the ANC Government faced the challenge of restructuring an unsustainably large defence sector. This was in the context of economic and social problems and a declining international arms market. This paper considers the restructuring of the South African industry over that period and more recently, providing a valuable case study of defence industrial restructuring in a small industrialised economy. It considers how the public sector (DENEL) and private sector r...

  5. Contrasting ontogenetic trajectories for phenolic and terpenoid defences in Eucalyptus froggattii

    Science.gov (United States)

    Goodger, Jason Q. D.; Heskes, Allison M.; Woodrow, Ian E.

    2013-01-01

    Background and Aims Plant defence metabolites are considered costly due to diversion of energy and nutrients away from growth. These costs combined with changes in resource availability and herbivory throughout plant ontogeny are likely to promote changes in defence metabolites. A comprehensive understanding of plant defence strategy requires measurement of lifetime ontogenetic trajectories – a dynamic component largely overlooked in plant defence theories. This study aimed to compare ontogenetic trajectories of foliar phenolics and terpenoids. Phenolics are predicted to be inexpensive to biosynthesize, whereas expensive terpenoids also require specialized, non-photosynthetic secretory structures to avoid autotoxicity. Based on these predicted costs, it is hypothesized that phenolics would be maximally deployed early in ontogeny, whereas terpenoids would be maximally deployed later, once the costs of biosynthesis and foregone photosynthesis could be overcome by enhanced resource acquisition. Methods Leaves were harvested from a family of glasshouse-grown Eucalyptus froggattii seedlings, field-grown saplings and the maternal parent tree, and analysed for total terpenoids and phenolics. Key Results Foliar phenolics were highest in young seedlings and lowest in the adult tree. Indeed the ratio of total phenolics to total terpenoids decreased in a significantly exponential manner with plant ontogeny. Most individual terpene constituents increased with plant ontogeny, but some mono- and sesquiterpenes remained relatively constant or even decreased in concentration as plants aged. Conclusions Plant ontogeny can influence different foliar defence metabolites in directionally opposite ways, and the contrasting trajectories support our hypothesis that phenolics would be maximally deployed earlier than terpenoids. The results highlight the importance of examining ontogenetic trajectories of defence traits when developing and testing theories of plant defence, and

  6. How Strong Is Europeanisation, Really? The Danish Defence Administration and the Opt-Out from the European Security and Defence Policy

    DEFF Research Database (Denmark)

    Olsen, Gorm Rye

    2011-01-01

    thesis. The article shows that in spite of the opt-out, the administrative structures and the policy processes in the Ministry of Foreign Affairs (MFA) have adapted to the common foreign and security policy (CFSP) and the European security and defence policy (ESDP). Surprisingly, the administrative...... is not an explanation of administrative adaptation. The pressure from Europeanisation has to be propagated by actors. In the case of the Danish defence administration, the promoter is government officials embedded in a domestic political-bureaucratic environment, which is remarkably positive towards the integration...

  7. Host seeking parasitic nematodes use specific odors to assess host resources.

    Science.gov (United States)

    Baiocchi, Tiffany; Lee, Grant; Choe, Dong-Hwan; Dillman, Adler R

    2017-07-24

    Entomopathogenic nematodes (EPNs) are insect parasites used as biological control agents. Free-living infective juveniles (IJs) of EPNs employ host-seeking behaviors to locate suitable hosts for infection. We found that EPNs can differentiate between naïve and infected hosts, and that host attractiveness changes over time in a species-specific manner. We used solid-phase microextraction and gas chromatography/mass spectrometry to identify volatile chemical cues that may relay information about a potential host's infection status and resource availability. Among the chemicals identified from the headspace of infected hosts, 3-Methyl-2-buten-1-ol (prenol) and 3-Hydroxy-2-butanone (AMC) were selected for further behavioral assays due to their temporal correlation with the behavioral changes of IJs towards the infected hosts. Both compounds were repulsive to IJs of Steinernema glaseri and S. riobrave in a dose-dependent manner when applied on an agar substrate. Furthermore, the repulsive effects of prenol were maintained when co-presented with the uninfected host odors, overriding attraction to uninfected hosts. Prenol was attractive to dauers of some free-living nematodes and insect larvae. These data suggest that host-associated chemical cues may have several implications in EPN biology, not only as signals for avoidance and dispersal of conspecifics, but also as attractants for new potential hosts.

  8. Should I fight or should I grow now? The role of cytokinins in plant growth and immunity and in the growth-defence trade-off.

    Science.gov (United States)

    Albrecht, Tessa; Argueso, Cristiana T

    2017-03-01

    Perception and activation of plant immunity require a remarkable level of signalling plasticity and control. In Arabidopsis and other plant species, constitutive defence activation leads to resistance to a broad spectrum of biotrophic pathogens, but also frequently to stunted growth and reduced seed set. Plant hormones are important integrators of the physiological responses that influence the outcome of plant-pathogen interactions. We review the mechanisms by which the plant hormone cytokinin regulates both plant growth and response to pathogens, and how cytokinins may connect these two processes, ultimately affecting the growth trade-offs observed in plant immunity.

  9. Discordancy or template-based recognition? Dissecting the cognitive basis of the rejection of foreign eggs in hosts of avian brood parasites

    NARCIS (Netherlands)

    Moskat, Csaba; Ban, Miklos; Szekely, Tamas; Komdeur, Jan; Lucassen, Rim W. G.; van Boheemen, Lotte A.; Hauber, Mark E.

    2010-01-01

    Many avian hosts have evolved antiparasite defence mechanisms, including egg rejection, to reduce the costs of brood parasitism. The two main alternative cognitive mechanisms of egg discrimination are thought to be based on the perceived discordancy of eggs in a clutch or the use of recognition

  10. Fungal transcriptomics from host samples

    Directory of Open Access Journals (Sweden)

    Sara eAmorim-Vaz

    2016-01-01

    Full Text Available Candida albicans adaptation to the host requires a profound reprogramming of the fungal transcriptome as compared to in vitro laboratory conditions. A detailed knowledge of the C. albicans transcriptome during the infection process is necessary in order to understand which of the fungal genes are important for host adaptation. Such genes could be thought of as potential targets for antifungal therapy. The acquisition of the C. albicans transcriptome is however technically challenging due to the low proportion of fungal RNA in host tissues. Two emerging technologies were used recently to circumvent this problem. One consists of the detection of low abundance fungal RNA using capture and reporter gene probes which is followed by emission and quantification of resulting fluorescent signals (nanoString. The other is based first on the capture of fungal RNA by short biotinylated oligonucleotide baits covering the C. albicans ORFome permitting fungal RNA purification. Next, the enriched fungal RNA is amplified and subjected RNA sequencing (RNA-seq. Here we detail these two transcriptome approaches and discuss their advantages and limitations and future perspectives in microbial transcriptomics from host material.

  11. Politics, pleasure, violence: Swedish defence propaganda in social media

    Directory of Open Access Journals (Sweden)

    Rodrigo Ferrada Stoehrel

    2013-10-01

    Full Text Available In recent years, the Swedish Armed Forces have produced and distributed highly edited video clips on YouTube that show moving images of military activity. Alongside this development, mobile phone apps have emerged as an important channel through which the user can experience and take an interactive part in the staging of contemporary armed conflict. This article examines the way in which the aesthetic and affective experience of Swedish defence and security policy is socially and (media-culturally (co-constructed and how the official representation of Swedish military intervention (reproduces political and economic effects when these activities are distributed through traditional and social media such as YouTube and digital apps. Based on Isabela and Norman Fairclough’s thoughts on political discourse, Michel Foucault’s dialectic idea of power/knowledge, and Sara Ahmed’s concept of the affective, I discuss how the Swedish digital military aesthetic is part of a broader political and economic practice which has consequences beyond the digital, the semiotic and what might at first glance appear to be pure entertainment. 

  12. Politics, pleasure, violence: Swedish defence propaganda in social media

    Directory of Open Access Journals (Sweden)

    Rodrigo Ferrada Stoehrel

    2013-12-01

    Full Text Available In recent years, the Swedish Armed Forces have produced and distributed highly edited video clips on YouTube that show moving images of military activity. Along- side this development, mobile phone apps have emerged as an important channel through which the user can experience and take an interactive part in the staging of contemporary armed conflict. This article examines the way in which the aes- thetic and affective experience of Swedish defence and security policy is socially and (media-culturally (co-constructed and how the official representation of Swedish military intervention (reproduces political and economic effects when these activi- ties are distributed through traditional and social media such as YouTube and digital apps. Based on Isabela and Norman Fairclough’s thoughts on political discourse, Michel Foucault’s dialectic idea of power/knowledge, and Sara Ahmed’s concept of the affective, I discuss how the Swedish digital military aesthetic is part of a broader political and economic practice that has consequences beyond the digital, the semi- otic, and what might at first glance appear to be pure entertainment.

  13. Psychic skin: psychotic defences, borderline process and delusions.

    Science.gov (United States)

    Schmidt, Martin

    2012-02-01

    In this paper, I apply the concept of psychic skin to analytic work with people suffering from personality disorders and psychoses. When psychoses emerge, the defensive skin which protects the ego is breached and violent unconscious forces rip through the personality. Some of the patients diagnosed as schizophrenic with whom I work have identified with archetypal characters such as Christ, Satan, John Lennon and the Queen. I attempt to show how the adoption of these inflated personas can serve as secondary psychic skins. Such delusional identifications can provide a protective shield to hide the denuded self and prevent intrusion from the external world. Through clinical example, I try to demonstrate how these archetypal 'second skins' can preserve life until internal and external conditions make it possible for the self to emerge. I contrast such psychotic identifications with 'thin-skinned' and 'thick-skinned' narcissism as well as 'defences of the self' in borderline states where the psychic skin may be damaged but does not disintegrate. I also look at the ways in which Jung's own personal experience was different from this and how he managed to avert psychotic breakdown. © 2012, The Society of Analytical Psychology.

  14. Faba bean forisomes can function in defence against generalist aphids.

    Science.gov (United States)

    Medina-Ortega, Karla J; Walker, Gregory P

    2015-06-01

    Phloem sieve elements have shut-off mechanisms that prevent loss of nutrient-rich phloem sap when the phloem is damaged. Some phloem proteins such as the proteins that form forisomes in legume sieve elements are one such mechanism and in response to damage, they instantly form occlusions that stop the flow of sap. It has long been hypothesized that one function of phloem proteins is defence against phloem sap-feeding insects such as aphids. This study provides the first experimental evidence that aphid feeding can induce phloem protein occlusion and that the aphid-induced occlusions inhibit phloem sap ingestion. The great majority of phloem penetrations in Vicia faba by the generalist aphids Myzus persicae and Macrosiphum euphorbiae triggered forisome occlusion and the aphids eventually withdrew their stylets without ingesting phloem sap. This contrasts starkly with a previous study on the legume-specialist aphid, Acyrthosiphon pisum, where penetration of faba bean sieve elements did not trigger forisome occlusion and the aphids readily ingested phloem sap. Next, forisome occlusion was demonstrated to be the cause of failed phloem ingestion attempts by M. persicae: when occlusion was inhibited by the calcium channel blocker lanthanum, M. persicae readily ingested faba bean phloem sap. © 2014 John Wiley & Sons Ltd.

  15. Competition induces allelopathy but suppresses growth and anti-herbivore defence in a chemically rich seaweed.

    Science.gov (United States)

    Rasher, Douglas B; Hay, Mark E

    2014-02-22

    Many seaweeds and terrestrial plants induce chemical defences in response to herbivory, but whether they induce chemical defences against competitors (allelopathy) remains poorly understood. We evaluated whether two tropical seaweeds induce allelopathy in response to competition with a reef-building coral. We also assessed the effects of competition on seaweed growth and seaweed chemical defence against herbivores. Following 8 days of competition with the coral Porites cylindrica, the chemically rich seaweed Galaxaura filamentosa induced increased allelochemicals and became nearly twice as damaging to the coral. However, it also experienced significantly reduced growth and increased palatability to herbivores (because of reduced chemical defences). Under the same conditions, the seaweed Sargassum polycystum did not induce allelopathy and did not experience a change in growth or palatability. This is the first demonstration of induced allelopathy in a seaweed, or of competitors reducing seaweed chemical defences against herbivores. Our results suggest that the chemical ecology of coral-seaweed-herbivore interactions can be complex and nuanced, highlighting the need to incorporate greater ecological complexity into the study of chemical defence.

  16. The correlated evolution of antipredator defences and brain size in mammals.

    Science.gov (United States)

    Stankowich, Theodore; Romero, Ashly N

    2017-01-11

    Mammals that possess elaborate antipredator defences such as body armour, spines and quills are usually well protected, intermediate in size, primarily insectivorous and live in simple open environments. The benefits of such defences seem clear and may relax selection on maintaining cognitive abilities that aid in vigilance and predator recognition, and their bearers may accrue extensive production and maintenance costs. Here, in this comparative phylogenetic analysis of measurements of encephalization quotient and morphological defence scores of 647 mammal species representing nearly every order, we found that as lineages evolve stronger defences, they suffer a correlated reduction in encephalization. The only exceptions were those that live in trees-a complex three-dimensional world probably requiring greater cognitive abilities. At the proximate level, because brain tissue is extremely energetically expensive to build, mammals may be trading off spending more on elaborate defences and saving by building less powerful brains. At the ultimate level, having greater defences may also reduce the need for advanced cognitive abilities for constant assessment of environmental predation risk, especially in simple open environments. © 2017 The Author(s).

  17. La signalisation hormonale dans la résistance des plantes aux bioagresseurs = Hormone signalling in plant resistance

    OpenAIRE

    Jalloul, A.; Clérivet, Alain; Nicole, Michel

    2009-01-01

    Plant survival to biotic stresses results from various defence strategies. Depending on the pathogen and nature of the parasitism, a plant will adapt its responses through a fine tuning regulation of defence mechanisms under the control of its hormones whose functions will be reoriented. Salicylic acid, jasmonic acid and ethylene drive signalling pathways, the role of which is well established in plant resistance. However, additional hormones, including abscisic acid, seem to have an essentia...

  18. Fitness costs of animal medication: antiparasitic plant chemicals reduce fitness of monarch butterfly hosts.

    Science.gov (United States)

    Tao, Leiling; Hoang, Kevin M; Hunter, Mark D; de Roode, Jacobus C

    2016-09-01

    The emerging field of ecological immunology demonstrates that allocation by hosts to immune defence against parasites is constrained by the costs of those defences. However, the costs of non-immunological defences, which are important alternatives to canonical immune systems, are less well characterized. Estimating such costs is essential for our understanding of the ecology and evolution of alternative host defence strategies. Many animals have evolved medication behaviours, whereby they use antiparasitic compounds from their environment to protect themselves or their kin from parasitism. Documenting the costs of medication behaviours is complicated by natural variation in the medicinal components of diets and their covariance with other dietary components, such as macronutrients. In the current study, we explore the costs of the usage of antiparasitic compounds in monarch butterflies (Danaus plexippus), using natural variation in concentrations of antiparasitic compounds among plants. Upon infection by their specialist protozoan parasite Ophryocystis elektroscirrha, monarch butterflies can selectively oviposit on milkweed with high foliar concentrations of cardenolides, secondary chemicals that reduce parasite growth. Here, we show that these antiparasitic cardenolides can also impose significant costs on both uninfected and infected butterflies. Among eight milkweed species that vary substantially in their foliar cardenolide concentration and composition, we observed the opposing effects of cardenolides on monarch fitness traits. While high foliar cardenolide concentrations increased the tolerance of monarch butterflies to infection, they reduced the survival rate of caterpillars to adulthood. Additionally, although non-polar cardenolide compounds decreased the spore load of infected butterflies, they also reduced the life span of uninfected butterflies, resulting in a hump-shaped curve between cardenolide non-polarity and the life span of infected butterflies

  19. Escaping deleterious immune response in their hosts: lessons from trypanosomatids

    Directory of Open Access Journals (Sweden)

    Anne eGeiger

    2016-05-01

    Full Text Available The Trypanosomatidae family includes the genera Trypanosoma and Leishmania, protozoan parasites displaying complex digenetic life cycles requiring a vertebrate host and an insect vector. Trypanosoma brucei gambiense, T. cruzi and Leishmania spp are important human pathogens causing Human African Trypanosomiasis (HAT or Sleeping Sickness, Chagas’ disease, and various clinical forms of Leishmaniasis, respectively. They are transmitted to humans by tsetse flies, triatomine bugs or sandflies and affect millions of people worldwide.In humans, extracellular African trypanosomes (T. brucei evade the hosts’ immune defences, allowing their transmission to the next host, via the tsetse vector. By contrast, T. cruzi and Leishmania sp. have developed a complex intracellular lifestyle, also preventing several mechanisms to circumvent the host’s immune response.This review seeks to set out the immune evasion strategies developed by the different trypanosomatids resulting from parasite-host interactions and, will focus on: clinical and epidemiological importance of diseases; life cycles: parasites-hosts-vectors; innate immunity: key steps for trypanosomatids in invading hosts; deregulation of antigen presenting cells; disruption of efficient specific immunity; and the immune responses used for parasite proliferation.

  20. Evolution of spatially structured host-parasite interactions.

    Science.gov (United States)

    Lion, S; Gandon, S

    2015-01-01

    Spatial structure has dramatic effects on the demography and the evolution of species. A large variety of theoretical models have attempted to understand how local dispersal may shape the coevolution of interacting species such as host-parasite interactions. The lack of a unifying framework is a serious impediment for anyone willing to understand current theory. Here, we review previous theoretical studies in the light of a single epidemiological model that allows us to explore the effects of both host and parasite migration rates on the evolution and coevolution of various life-history traits. We discuss the impact of local dispersal on parasite virulence, various host defence strategies and local adaptation. Our analysis shows that evolutionary and coevolutionary outcomes crucially depend on the details of the host-parasite life cycle and on which life-history trait is involved in the interaction. We also discuss experimental studies that support the effects of spatial structure on the evolution of host-parasite interactions. This review highlights major similarities between some theoretical results, but it also reveals an important gap between evolutionary and coevolutionary models. We discuss possible ways to bridge this gap within a more unified framework that would reconcile spatial epidemiology, evolution and coevolution. © 2014 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2014 European Society For Evolutionary Biology.

  1. Host niches and defensive extended phenotypes structure parasitoid wasp communities.

    Directory of Open Access Journals (Sweden)

    Richard Bailey

    2009-08-01

    Full Text Available Oak galls are spectacular extended phenotypes of gallwasp genes in host oak tissues and have evolved complex morphologies that serve, in part, to exclude parasitoid natural enemies.Parasitoids and their insect herbivore hosts have coevolved to produce diverse communities comprising about a third of all animal species. The factors structuring these communities, however, remain poorly understood. An emerging theme in community ecology is the need to consider the effects of host traits, shaped by both natural selection and phylogenetic history, on associated communities of natural enemies. Here we examine the impact of host traits and phylogenetic relatedness on 48 ecologically closed and species-rich communities of parasitoids attacking gall-inducing wasps on oaks. Gallwasps induce the development of spectacular and structurally complex galls whose species- and generation-specific morphologies are the extended phenotypes of gallwasp genes. All the associated natural enemies attack their concealed hosts through gall tissues, and several structural gall traits have been shown to enhance defence against parasitoid attack. Here we explore the significance of these and other host traits in predicting variation in parasitoid community structure across gallwasp species. In particular, we test the "Enemy Hypothesis," which predicts that galls with similar morphology will exclude similar sets of parasitoids and therefore have similar parasitoid communities. Having controlled for phylogenetic patterning in host traits and communities, we found significant correlations between parasitoid community structure and several gall structural traits (toughness, hairiness, stickiness, supporting the Enemy Hypothesis. Parasitoid community structure was also consistently predicted by components of the hosts' spatiotemporal niche, particularly host oak taxonomy and gall location (e.g., leaf versus bud versus seed. The combined explanatory power of structural and

  2. The end of ambivalence and the triumph of pragmatism? Franco-British defence cooperation and European and Atlantic defence policy traditions

    NARCIS (Netherlands)

    Ostermann, F.

    2015-01-01

    This article investigates the Franco-British rapprochement in security and defence cooperation under Nicolas Sarkozy, Gordon Brown and David Cameron from 2008 to 2012. While in the past British Atlanticism and the French Europeanist tradition had stood in the way of close bilateral cooperation, the

  3. Host responses in life-history traits and tolerance to virus infection in Arabidopsis thaliana.

    Directory of Open Access Journals (Sweden)

    Israel Pagán

    2008-08-01

    Full Text Available Knowing how hosts respond to parasite infection is paramount in understanding the effects of parasites on host populations and hence host-parasite co-evolution. Modification of life-history traits in response to parasitism has received less attention than other defence strategies. Life-history theory predicts that parasitised hosts will increase reproductive effort and accelerate reproduction. However, empirical analyses of these predictions are few and mostly limited to animal-parasite systems. We have analysed life-history trait responses in 18 accessions of Arabidopsis thaliana infected at two different developmental stages with three strains of Cucumber mosaic virus (CMV. Accessions were divided into two groups according to allometric relationships; these groups differed also in their tolerance to CMV infection. Life-history trait modification upon virus infection depended on the host genotype and the stage at infection. While all accessions delayed flowering, only the more tolerant allometric group modified resource allocation to increase the production of reproductive structures and progeny, and reduced the length of reproductive period. Our results are in agreement with modifications of life-history traits reported for parasitised animals and with predictions from life-history theory. Thus, we provide empirical support for the general validity of theoretical predictions. In addition, this experimental approach allowed us to quantitatively estimate the genetic determinism of life-history trait plasticity and to evaluate the role of life-history trait modification in defence against parasites, two largely unexplored issues.

  4. Abiotic Stresses Antagonize the Rice Defence Pathway through the Tyrosine-Dephosphorylation of OsMPK6.

    Directory of Open Access Journals (Sweden)

    Yoshihisa Ueno

    2015-10-01

    Full Text Available Plants, as sessile organisms, survive environmental changes by prioritizing their responses to the most life-threatening stress by allocating limited resources. Previous studies showed that pathogen resistance was suppressed under abiotic stresses. Here, we show the mechanism underlying this phenomenon. Phosphorylation of WRKY45, the central transcription factor in salicylic-acid (SA-signalling-dependent pathogen defence in rice, via the OsMKK10-2-OsMPK6 cascade, was required to fully activate WRKY45. The activation of WRKY45 by benzothiadiazole (BTH was reduced under low temperature and high salinity, probably through abscisic acid (ABA signalling. An ABA treatment dephosphorylated/inactivated OsMPK6 via protein tyrosine phosphatases, OsPTP1/2, leading to the impaired activation of WRKY45 and a reduction in Magnaporthe oryzae resistance, even after BTH treatment. BTH induced a strong M. oryzae resistance in OsPTP1/2 knockdown rice, even under cold and high salinity, indicating that OsPTP1/2 is the node of SA-ABA signalling crosstalk and its down-regulation makes rice disease resistant, even under abiotic stresses. These results points to one of the directions to further improve crops by managing the tradeoffs between different stress responses of plants.

  5. Microcins in action: amazing defence strategies of Enterobacteria.

    Science.gov (United States)

    Rebuffat, Sylvie

    2012-12-01

    Probably the oldest and most widespread antimicrobial strategy in living organisms is the use of antimicrobial peptides. Bacteria secrete such defence peptides, termed bacteriocins, that they use for microbial competitions. Microcins are bacteriocins of less than 10 kDa produced by Escherichia coli and related enterobacteria through the ribosomal pathway. They are synthesized as linear precursors, which can further undergo complex post-translational modifications resulting from dedicated maturation enzymes encoded in the microcin gene clusters, and are processed by proteolytic cleavage. Microcins exert potent bactericidal activities that use subtle and clever mechanisms to cross outer and inner membranes of Gram-negative bacteria. To cross the outer membrane, siderophore-microcins hijack receptors involved in iron acquisition. The lasso-peptide microcin J25, which is characterized by a knotted arrangement where the C-terminal tail is threaded through an N-terminal macrolactam ring, uses a hydroxamate siderophore receptor and the inner-membrane protein SbmA for import in sensitive bacteria, where it inhibits bacterial transcription through binding to RNAP (RNA polymerase). Microcin C produced as a heptapeptide adenylate, requires an outer-membrane porin and an inner-membrane ABC (ATP-binding-cassette) transporter to reach the cytoplasm of target bacteria, where it is processed by proteases into a non-hydrolysable aspartyl-adenylate analogue. Therefore, despite showing different killing mechanisms and the absence of any structural homology, microcins have the common characteristic to use Trojan horse strategies to destroy their competitors. They offer new and promising tracks for further design and engineering of novel efficient antibiotics.

  6. Effectiveness evaluation of flood defence structures in different geomorphological contexts

    Science.gov (United States)

    Morelli, Stefano; Pazzi, Veronica; Fanti, Riccardo

    2017-04-01

    The flood risk in different geomorphological contexts of two less developed countries are investigated in order to evaluate the efficacy of the existing flood defence structures. In particular, a recent floodplain crossed by a wide meandering river and a narrow mountain valley flowed by creek with a torrential regime have been chosen for such analysis in North Albania and central Mexico, respectively. Both areas have been affected by disastrous floods in past years with considerable damages to properties and people. Some safety countermeasures have been performed over time, even if in a non-systematic way. For this reason, the current inclination to flood risk was assessed by means of a freeware software designed to perform one-dimensional (1D) hydraulic modelling for a full network of natural and anthropic channels (HEC-RAS software by Hydrologic Engineering Center River Analysis System). This new analyses take into account: i) the natural morphological variability along the river path, ii) the anthropic interventions on the fluvial dynamics, iii) the landscape appearance after the soil exploitation in the past years, and iv) all the changes induced by an exceeded informal urbanization. The reconstruction of the river and bordering areas geometric data was carried out according to the physical characteristics of the local environment: a bathymetric survey and near-river DGPS acquisitions for the open spaces of the Albanian floodplain, and traditional topographic methods for the highly vegetated Mexican valley. In both cases, the results show that the existing works are, on their own, poorly efficient in containing the predictable floods. Albanians levees seem underdimensioned, while the channelling works are too narrow to contain large amounts of water and solid transport as typical of the Mexican study area. Evidently, a new territorial planning is required in these areas, and some projects are now in place. However, it would be desirable that local authorities

  7. A Defence of Constructionism: Philosophy as Conceptual Engineering

    Directory of Open Access Journals (Sweden)

    Luciano Floridi

    2017-08-01

    Full Text Available The article offers a broad account and a defence of constructionism, both as a metaphilosophical approach and as a philosophical methodology, with some references to the philosophical tradition that has inspired it, the so-called «maker’s knowledge» tradition. The main thesis defended is that Plato’s «user’s knowledge tradition» should be complemented, if not replaced, by a constructionist approach to philosophical problems in general and to knowledge in particular. To put it simply, an epistemic agent knows something when that agent is able to build (reproduce, simulate, model, construct etc. that something and plug the obtained information in the correct network of relations that account for it. Or in even more intuitive terms, an agent qualifies as an epistemic agent not when she is a passive user of some information, but when she is a critical producer of it. Her epistemic expertise increases in relation to the scope and depth of the questions that is able to ask and answer on a particular topic. The maker’s knowledge is knowledge of the ontology of the semantic artefact and this is a fundamental epistemological lesson we can learn from poietic disciplines such as computer science and economics. So constructionism shifts the focus away from the mimetic, passive and declarative knowledge that something is the case, in order to concentrate more on the poietic, interactive and practical knowledge of something being the case, that is, of semantic artefacts. Once applied to the interpretation of philosophy itself, constructionism suggests adding conceptual engineering to conceptual analysis as a fundamental method.

  8. Eales′ disease: Oxidant stress and weak antioxidant defence

    Directory of Open Access Journals (Sweden)

    Ramakrishnan S

    2007-01-01

    Full Text Available Eales′ disease (ED is an idiopathic retinal periphlebitis characterized by capillary non-perfusion and neovascularization. In addition to the existing system, a new staging system has been proposed by Saxena et al . Immunological, molecular biological and biochemical studies have indicated the role of human leucocyte antigen, retinal S antigen autoimmunity, Mycobacterium tuberculosis genome, free radical damage and possibly hyperhomocysteinemia in its etiopathogenesis, which appears multifactorial. Oxidant stress has been shown by increase in the levels of thiobarbituric acid reactive substances (lipid oxidation in the vitreous, erythrocytes, platelets, and monocytes. A decrease in vitamins E and C both in active and healed vasculitis, superoxide dismutase, glutathione, and glutathione peroxidase showed a weakened antioxidant defence. Epiretinal membrane from patients of ED who underwent surgery showed, by immunolocalization, presence of carboxy methyl lysine, an advanced glycation end product formed by glycoxidation and is involved in angiogenesis. OH· free radical accumulation in monocytes has been directly shown by electron spin resonance spectrometry. Free radical damage to DNA and of protein was shown by the accumulation of 8 hydroxy 2 deoxyguanosine (in leucocytes and nitrotyrosine (in monocytes, respectively. Nitrosative stress was shown by increased expression of inducible nitric oxide synthase in monocytes in which levels of iron and copper were increased while those of zinc decreased. A novel 88 kDa protein was found in serum and vitreous in inflammatory condition and had antioxidant function. Platelet fluidity was also affected. Oral, methotrexate in low dosage (12.5 mg/week for 12 weeks as well as oral vitamin E (400 IU and C (500 mg daily for 8 weeks are reported to have beneficial effects.

  9. Modelling parasite transmission in a grazing system: the importance of host behaviour and immunity.

    Directory of Open Access Journals (Sweden)

    Naomi J Fox

    Full Text Available Parasitic helminths present one of the most pervasive challenges to grazing herbivores. Many macro-parasite transmission models focus on host physiological defence strategies, omitting more complex interactions between hosts and their environments. This work represents the first model that integrates both the behavioural and physiological elements of gastro-intestinal nematode transmission dynamics in a managed grazing system. A spatially explicit, individual-based, stochastic model is developed, that incorporates both the hosts' immunological responses to parasitism, and key grazing behaviours including faecal avoidance. The results demonstrate that grazing behaviour affects both the timing and intensity of parasite outbreaks, through generating spatial heterogeneity in parasite risk and nutritional resources, and changing the timing of exposure to the parasites' free-living stages. The influence of grazing behaviour varies with the host-parasite combination, dependent on the development times of different parasite species and variations in host immune response. Our outputs include the counterintuitive finding that under certain conditions perceived parasite avoidance behaviours (faecal avoidance can increase parasite risk, for certain host-parasite combinations. Through incorporating the two-way interaction between infection dynamics and grazing behaviour, the potential benefits of parasite-induced anorexia are also demonstrated. Hosts with phenotypic plasticity in grazing behaviour, that make grazing decisions dependent on current parasite burden, can reduce infection with minimal loss of intake over the grazing season. This paper explores how both host behaviours and immunity influence macro-parasite transmission in a spatially and temporally heterogeneous environment. The magnitude and timing of parasite outbreaks is influenced by host immunity and behaviour, and the interactions between them; the incorporation of both regulatory processes

  10. How is the development of dental biofilms influenced by the host?

    Science.gov (United States)

    Marsh, Philip D; Devine, Deirdre A

    2011-03-01

    The host provides environmental conditions that support diverse communities of microorganisms on all environmentally-exposed surfaces of the body. To review the literature to determine which properties of the host substantially influence the development of dental biofilms. The mouth facilitates the growth of a characteristic resident microbiota. The composition of the oral microbiota is influenced by temperature, pH, and atmosphere, as well as by the host defences and host genetics. In addition, the host supplies endogenous nutrients and a variety of surfaces for biofilm formation. In health, the resident oral microbiota forms a symbiotic relationship with the host, regulated by active host-microbe cross talk. This resident microbiota is sensitive to perturbations in the host environment, especially to changes in nutrient supply and pH, so that previously minor components of the microbiota can become more competitive (and vice versa), resulting in reorganization of biofilm community structure. The host environment dictates the composition and gene expression of the resident microbiota. Changes in oral environmental conditions can disrupt the normal symbiotic relationship between the host and its resident microbes, and increase the risk of disease. © 2011 John Wiley & Sons A/S.

  11. A shared chemical basis of avian host-parasite egg colour mimicry.

    Science.gov (United States)

    Igic, Branislav; Cassey, Phillip; Grim, Tomás; Greenwood, David R; Moskát, Csaba; Rutila, Jarkko; Hauber, Mark E

    2012-03-22

    Avian brood parasites lay their eggs in other birds' nests and impose considerable fitness costs on their hosts. Historically and scientifically, the best studied example of circumventing host defences is the mimicry of host eggshell colour by the common cuckoo (Cuculus canorus). Yet the chemical basis of eggshell colour similarity, which impacts hosts' tolerance towards parasitic eggs, remains unknown. We tested the alternative scenarios that (i) cuckoos replicate host egg pigment chemistry, or (ii) cuckoos use alternative mechanisms to produce a similar perceptual effect to mimic host egg appearance. In parallel with patterns of similarity in avian-perceived colour mimicry, the concentrations of the two key eggshell pigments, biliverdin and protoporphyrin, were most similar between the cuckoo host-races and their respective hosts. Thus, the chemical basis of avian host-parasite egg colour mimicry is evolutionarily conserved, but also intraspecifically flexible. These analyses of pigment composition reveal a novel proximate dimension of coevolutionary interactions between avian brood parasites and hosts, and imply that alternative phenotypes may arise by the modifications of already existing biochemical and physiological mechanisms and pathways.

  12. Proteins involved in attack and defence in Zygomycete-aphid interactions

    DEFF Research Database (Denmark)

    Grell, Morten Nedergaard; Jensen, Annette Bruun; Lange, Lene

    2009-01-01

    Fungi within the order Entomophthorales (Zygomycota) are obligate biotrophic pathogens of insects. Initially, the fungi penetrate the cuticle of their host, where after they grow with a protoplast-like morphology within the host, slowly degrading and eventually killing it. We have performed...... a secretome study of field collected grain aphids (Sitobion avenae) in early stages of infection with entomophthoralean fungi using the transposon assisted signal trapping (TAST) technology (Becker et al. 2004, J Microbiol Methods 57, 123-133), thereby discovering a series of secreted enzymes of the pathogens......, and additional related fungi are under investigation. We anticipate that our work will shed light on this highly specialized group of fungi that has attracted substantial attention as potential bio-control agents....

  13. Effects of elevated [CO2] on maize defence against mycotoxigenic Fusarium verticillioides

    Science.gov (United States)

    Vaughan, Martha M; Huffaker, Alisa; Schmelz, Eric A; Dafoe, Nicole J; Christensen, Shawn; Sims, James; Martins, Vitor F; Swerbilow, Jay; Romero, Maritza; Alborn, Hans T; Allen, Leon HARTWELL; Teal, Peter EA

    2014-01-01

    Maize is by quantity the most important C4 cereal crop; however, future climate changes are expected to increase maize susceptibility to mycotoxigenic fungal pathogens and reduce productivity. While rising atmospheric [CO2] is a driving force behind the warmer temperatures and drought, which aggravate fungal disease and mycotoxin accumulation, our understanding of how elevated [CO2] will effect maize defences against such pathogens is limited. Here we report that elevated [CO2] increases maize susceptibility to Fusarium verticillioides proliferation, while mycotoxin levels are unaltered. Fumonisin production is not proportional to the increase in F. verticillioides biomass, and the amount of fumonisin produced per unit pathogen is reduced at elevated [CO2]. Following F. verticillioides stalk inoculation, the accumulation of sugars, free fatty acids, lipoxygenase (LOX) transcripts, phytohormones and downstream phytoalexins is dampened in maize grown at elevated [CO2]. The attenuation of maize 13-LOXs and jasmonic acid production correlates with reduced terpenoid phytoalexins and increased susceptibility. Furthermore, the attenuated induction of 9-LOXs, which have been suggested to stimulate mycotoxin biosynthesis, is consistent with reduced fumonisin per unit fungal biomass at elevated [CO2]. Our findings suggest that elevated [CO2] will compromise maize LOX-dependent signalling, which will influence the interactions between maize and mycotoxigenic fungi. Elevated [CO2] increases maize susceptibility to Fusarium verticillioides proliferation but mycotoxin levels are unaltered. The attenuation of maize 13-LOXs and JA production correlates with reduced terpenoid phytoalexins and increased susceptibility. Furthermore, the attenuated induction of 9-LOXs, which have been suggested to stimulate mycotoxin biosynthesis, is consistent with reduced fumonisin per unit fungal biomass at elevated [CO2]. PMID:24689748

  14. Hexanoic acid protects tomato plants against Botrytis cinerea by priming defence responses and reducing oxidative stress.

    Science.gov (United States)

    Finiti, Ivan; de la O Leyva, María; Vicedo, Begonya; Gómez-Pastor, Rocío; López-Cruz, Jaime; García-Agustín, Pilar; Real, Maria Dolores; González-Bosch, Carmen

    2014-08-01

    Treatment with the resistance priming inducer hexanoic acid (Hx) protects tomato plants from Botrytis cinerea by activating defence responses. To investigate the molecular mechanisms underlying hexanoic acid-induced resistance (Hx-IR), we compared the expression profiles of three different conditions: Botrytis-infected plants (Inf), Hx-treated plants (Hx) and Hx-treated + infected plants (Hx+Inf). The microarray analysis at 24 h post-inoculation showed that Hx and Hx+Inf plants exhibited the differential expression and priming of many Botrytis-induced genes. Interestingly, we found that the activation by Hx of other genes was not altered by the fungus at this time point. These genes may be considered to be specific targets of the Hx priming effect and may help to elucidate its mechanisms of action. It is noteworthy that, in Hx and Hx+Inf plants, there was up-regulation of proteinase inhibitor genes, DNA-binding factors, enzymes involved in plant hormone signalling and synthesis, and, remarkably, the genes involved in oxidative stress. Given the relevance of the oxidative burst occurring in plant-pathogen interactions, the effect of Hx on this process was studied in depth. We showed by specific staining that reactive oxygen species (ROS) accumulation in Hx+Inf plants was reduced and more restricted around infection sites. In addition, these plants showed higher ratios of reduced to oxidized glutathione and ascorbate, and normal levels of antioxidant activities. The results obtained indicate that Hx protects tomato plants from B. cinerea by regulating and priming Botrytis-specific and non-specific genes, preventing the harmful effects of oxidative stress produced by infection. © 2013 BSPP AND JOHN WILEY & SONS LTD.

  15. Wound-induced proteinase inhibitor in Salix viminalis and its association with defence against insects

    Energy Technology Data Exchange (ETDEWEB)

    Saarikoski, P. [Swedish Univ. of Agricultural Sciences, Uppsala (Sweden). Dept. of Forest Genetics

    1997-09-01

    For successful traditional breeding, the plant material has to be screened for genetic variation for the desired traits. By screening Salix clones for wound-induced proteinase inhibitor (PI) activity and ethylene evolution, it was possible to identify variation for both characters among the Salix clones tested. However, no correlation was observed with insect and pathogen resistance. Since there was no simple relationship between wound-induced ethylene production, accumulation of PI and pest resistance, a more systematic investigation of Salix PIs was begun. A gene (swin1.1) encoding a 21 kDa trypsin inhibitor with characteristics of Kunitz-type of PI was sequenced. The trypsin inhibitor encoded by the isolated swin1.1 gene was shown to be functional in vitro and exhibit specificity for trypsin. It is therefore likely that this PI is involved in the plant defence in Salix, since many insects have trypsin as their major digestive protease. In further support of this view, in bio-tests with poplar the mortality of the first instar larvae (Lymantria dispar) was significantly increased, both after application of the trypsin inhibitor encoded by swin1.1 directly on poplar leaves and after feeding the larvae with transgenic poplar over-expressing the swin1.1 gene. In Salix, the swin1.1 gene was shown to be induced by mechanical wounding, insect feeding and by treatment with the signalling substances salicylic and jasmonic acid. The locally wound-induced response (mechanical and insect) was greater than the systemic response. Other swin1 gene family members were also differentially expressed after the inductive treatment. 187 refs., 3 figs., 2 tabs.

  16. Impact of the age of Biomphalaria alexandrina snails on Schistosoma mansoni transmission: modulation of the genetic outcome and the internal defence system of the snail

    Science.gov (United States)

    Abou-El-Naga, Iman Fathy; Sadaka, Hayam Abd El-Monem; Amer, Eglal Ibrahim; Diab, Iman Hassan; Khedr, Safaa Ibrahim Abd El-Halim

    2015-01-01

    Of the approximately 34 identified Biomphalaria species,Biomphalaria alexandrina represents the intermediate host of Schistosoma mansoni in Egypt. Using parasitological and SOD1 enzyme assay, this study aimed to elucidate the impact of the age of B. alexandrina snails on their genetic variability and internal defence against S. mansoni infection. Susceptible and resistant snails were reared individually for self-reproduction; four subgroups of their progeny were used in experiment. The young susceptible subgroup showed the highest infection rate, the shortest pre-patent period, the highest total cercarial production, the highest mortality rate and the lowest SOD1 activity. Among the young and adult susceptible subgroups, 8% and 26% were found to be resistant, indicating the inheritance of resistance alleles from parents. The adult resistant subgroup, however, contained only resistant snails and showed the highest enzyme activity. The complex interaction between snail age, genetic background and internal defence resulted in great variability in compatibility patterns, with the highest significant difference between young susceptible and adult resistant snails. The results demonstrate that resistance alleles function to a greater degree in adults, with higher SOD1 activity and provide potential implications for Biomphalaria control. The identification of the most susceptible snail age enables determination of the best timing for applying molluscicides. Moreover, adult resistant snails could be beneficial in biological snail control. PMID:26061235

  17. Impact of the age of Biomphalaria alexandrina snails on Schistosoma mansoni transmission: modulation of the genetic outcome and the internal defence system of the snail

    Directory of Open Access Journals (Sweden)

    Iman Fathy Abou-El-Naga

    2015-08-01

    Full Text Available Of the approximately 34 identified Biomphalariaspecies,Biomphalaria alexandrinarepresents the intermediate host of Schistosoma mansoniin Egypt. Using parasitological and SOD1 enzyme assay, this study aimed to elucidate the impact of the age of B. alexandrinasnails on their genetic variability and internal defence against S. mansoniinfection. Susceptible and resistant snails were reared individually for self-reproduction; four subgroups of their progeny were used in experiment. The young susceptible subgroup showed the highest infection rate, the shortest pre-patent period, the highest total cercarial production, the highest mortality rate and the lowest SOD1 activity. Among the young and adult susceptible subgroups, 8% and 26% were found to be resistant, indicating the inheritance of resistance alleles from parents. The adult resistant subgroup, however, contained only resistant snails and showed the highest enzyme activity. The complex interaction between snail age, genetic background and internal defence resulted in great variability in compatibility patterns, with the highest significant difference between young susceptible and adult resistant snails. The results demonstrate that resistance alleles function to a greater degree in adults, with higher SOD1 activity and provide potential implications for Biomphalariacontrol. The identification of the most susceptible snail age enables determination of the best timing for applying molluscicides. Moreover, adult resistant snails could be beneficial in biological snail control.

  18. Induced defences alter the strength and direction of natural selection on reproductive traits in common milkweed.

    Science.gov (United States)

    Thompson, K A; Cory, K A; Johnson, M T J

    2017-06-01

    Evolutionary biologists have long sought to understand the ecological processes that generate plant reproductive diversity. Recent evidence indicates that constitutive antiherbivore defences can alter natural selection on reproductive traits, but it is unclear whether induced defences will have the same effect and whether reduced foliar damage in defended plants is the cause of this pattern. In a factorial field experiment using common milkweed, Asclepias syriaca L., we induced plant defences using jasmonic acid (JA) and imposed foliar damage using scissors. We found that JA-induced plants experienced selection for more inflorescences that were smaller in size (fewer flowers), whereas control plants only experienced a trend towards selection for larger inflorescences (more flowers); all effects were independent of foliar damage. Our results demonstrate that induced defences can alter both the strength and direction of selection on reproductive traits, and suggest that antiherbivore defences may promote the evolution of plant reproductive diversity. © 2017 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2017 European Society For Evolutionary Biology.

  19. Crowd-out of defence and health spending: is Israel different from other industrialised nations?

    Science.gov (United States)

    Reeves, Aaron; Stuckler, David

    2013-04-22

    Does high defence spending limit the growth of public health investment? Using comparative data from 31 OECD countries between 1980 and 2010, we find little evidence that defence crowds out public health spending. Whether measured in terms of long-term levels or short-term changes, per capita defence and health spending positively and significantly correlate. To investigate the possibility that countries with high security needs such as Israel exhibit differing patterns, we also compare crowd-out among countries experiencing violent conflicts as well as current high military-spending countries. We observed a greater positive correlation between changes in health and defence spending among conflict-countries (r = 0.65, p military spending countries, Israel's politicians reduced defence spending while increasing health expenditure during its recent recession. These analyses reveal that while Israel's politicians have chronically underinvested in public health, there are modest steps being taken to rectify the country's unique and avoidable crowding out of public health from its high military spending.

  20. Inquiry into ’Personnel Wastage Rates in the Australian Defence Force’. (Second Submission to Defence Sub-Committee of the Joint Committee on Foreign Affairs, Defence and Trade)

    Science.gov (United States)

    1988-05-01

    QANTAS . Of the 110 pilot separations in 1986-87 36 were officers who joined QANTAS as pilots to continue their flying career. Of the likely 130 pilot...separations for 1987-88, about 52 are expected to join QANTAS . The Minister for Defence Science and Personnel is having discussions \\%ith QANTAS aimed at...A number of matters are still outstanding, including the greater use of QANTAS pilots in the RAAF Reserve and the timings of QANTAS training courses

  1. Initial Host Response to Bacteria in the Murine Lung Differs Between Pseudomonas aeruginosa, Staphylococcus aureus and Streptococcus pneumoniae.

    Science.gov (United States)

    Preu, Liselotte; Bischoff, Markus; Veith, Nils T; Rosenbruch, Martin; Theegarten, Dirk; Laschke, Matthias W; Meier, Carola; Tschernig, Thomas

    2016-04-01

    Phagocytosis of bacteria is an important process during early host defence. It has been directly observed only ex vivo or in vitro. Here, we report on the observation of phagocytosis under in vivo conditions by using intravital microscopy in the murine lung. Suspensions of fluorescently labelled Streptococcus pneumoniae, Staphylococcus aureus and Pseudomonas aeruginosa cells were each instilled intratracheally to anaesthetized mice. After thoracotomy, the alveolar surface was observed for 30 min. Alveolar phagocytes exhibiting ingested bacteria could be detected and counted. The highest numbers were found after the infection with P. aeruginosa. By using intravital microscopy, cellular host defence could be observed in living mice lungs. The initial phagocytic reaction crucially depends on the species of applied bacteria invading the lung.

  2. Bacterial Colonization and the Development of Intestinal Defences

    Directory of Open Access Journals (Sweden)

    Hai Ning Shi

    2004-01-01

    Full Text Available In humans, intestinal defences develop during gestation and, at full term, have the capacity to respond in an appropriate manner to infectious agents and foreign antigens. Before an active protective response can occur, however, the gut must first be exposed to colonizing bacteria. Colonization with diverse intestinal microbes is necessary for the development of important gut defenses such as the synthesis and secretion of polymeric immunoglobulin A and the generation of a balanced T helper (Th cell response. Insights into normal immune physiological development of the gut have been made by studying the germ-free animal and intestinal defenses. These studies have provided insights into the physiology of immune responses. Two important immunological functions are the secretion of polymeric immunoglobulin A to protect the intestinal surface against harmful stimuli and inhibition of the systemic response to commensal bacteria and food proteins (eg, oral tolerance to prevent chronic inflammation. Neither function exists in the germ-free state, but rapidly develops after conventionalization (colonization of the germ-free animal. In the present review, the importance of bacterial colonization on the appearance of normal mucosal immune function and to the clinical consequences of inadequate colonization to the development of disease will be discussed. For example, excessive Th2 activity can lead to atopy, whereas Th1 predominance is found in conditions such as Helicobacter pylori gastritis and Crohn's disease. With the eradication of infectious diseases in developed countries in the past three decades, the incidence of atopic and autoimmune diseases has increased. This epidemiological observation has been explained by the 'hygiene hypothesis', which suggests that a reduction in microbial burden by public health measures has contributed to an immunological imbalance in the intestine. A family of pattern recognition receptors (Toll-like receptors on gut

  3. HOST PLANT UTILIZATION, HOST RANGE OSCILLATIONS AND DIVERSIFICATION IN NYMPHALID BUTTERFLIES: A PHYLOGENETIC INVESTIGATION

    Science.gov (United States)

    Nylin, Sören; Slove, Jessica; Janz, Niklas

    2014-01-01

    It has been suggested that phenotypic plasticity is a major factor in the diversification of life, and that variation in host range in phytophagous insects is a good model for investigating this claim. We explore the use of angiosperm plants as hosts for nymphalid butterflies, and in particular the evidence for past oscillations in host range and how they are linked to host shifts and to diversification. At the level of orders of plants, a relatively simple pattern of host use and host shifts emerges, despite the 100 million years of history of the family Nymphalidae. We review the evidence that these host shifts and the accompanying diversifications were associated with transient polyphagous stages, as suggested by the “oscillation hypothesis.” In addition, we investigate all currently polyphagous nymphalid species and demonstrate that the state of polyphagy is rare, has a weak phylogenetic signal, and a very apical distribution in the phylogeny; we argue that these are signs of its transient nature. We contrast our results with data from the bark beetles Dendroctonus, in which a more specialized host use is instead the apical state. We conclude that plasticity in host use is likely to have contributed to diversification in nymphalid butterflies. PMID:24372598

  4. Host age modulates within-host parasite competition

    OpenAIRE

    Izhar, Rony; Routtu, Jarkko; Ben-Ami, Frida

    2015-01-01

    In many host populations, one of the most striking differences among hosts is their age. While parasite prevalence differences in relation to host age are well known, little is known on how host age impacts ecological and evolutionary dynamics of diseases. Using two clones of the water flea Daphnia magna and two clones of its bacterial parasite Pasteuria ramosa, we examined how host age at exposure influences within-host parasite competition and virulence. We found that multiply-exposed hosts...

  5. Review of Defence Plans in Europe: Current Status, Strengths and Opportunities

    DEFF Research Database (Denmark)

    De Boeck, Steven; Van Hertem, Dirk; Das, Kaushik

    2016-01-01

    electricity market is causing an increase in flows on interconnections between different areas of the European power system. Furthermore the time needed to construct new infrastructure pushes Transmission System Operators (TSOs) to better utilize the installed infrastructure. As the power system is strongly...... interconnected, a contingency in one area can affect the whole power system and possibly lead to a wide area black out. Therefore adequate defence plans need to be designed and in place to handle these situations. This paper starts with an overview of the terminology used in defence plans. Subsequently...... the current status of defence plans in Europe and the preferred sequence of actions to mitigate contingencies, is given based on a survey conducted among several European TSOs. Furthermore his paper gives an overview of how the ongoing changes with renewables, phasor measurement units (PMUs), power flow...

  6. Families of returned defence force personnel: a changing landscape of challenges.

    Science.gov (United States)

    Berle, David; Steel, Zachary

    2015-08-01

    This paper aims to identify the key challenges experienced by the families of defence force personnel following deployment. We undertook a selective review of four post-deployment challenges to the families of defence force personnel: (1) changes to relationships; (2) changes to family member roles and responsibilities; (3) adjustment of children and parenting challenges; and (4) anger, family conflict and violence. Emerging issues in the area of post-deployment adjustment are also discussed. Empirical studies of post-deployment family adjustment are lacking. Each of the reviewed challenges can contribute to psychological difficulties and precipitate contact with mental health services. The challenges faced by defence force personnel when returning from deployment arise within a family context. Clinicians should thoroughly assess these factors in families following deployment, but also recognise family strengths and resilience to these challenges. © The Royal Australian and New Zealand College of Psychiatrists 2015.

  7. The United Kingdom and the establishment of European Security and Defence Policy

    Directory of Open Access Journals (Sweden)

    Alexandru-Nicolae Cucu

    2014-04-01

    Full Text Available After the Labour Party came to power, Great Britain was actively implied in the negotiations and the decision-making processes that led to the construction of the European security and defence mechanism. The European Union’s new perspective regarding security and defence assumed after 1999 was mostly framed by British leaders who seized the inability of Europe to react during the Kosovo War. Although, at the beginning the United Kingdom reformed its internal mechanisms and assumed complex duties, the creation of European Security and Defence Policy did not abolish the North Atlantic security system, as Germans and French would have wanted. Beyond the United States mistrust, transatlantic cooperation continued, especially because of the UK which sought to strike the right balance between European theatre and the North-Atlantic one.

  8. Transcriptional regulation of defence genes and involvement of the WRKY transcription factor in arbuscular mycorrhizal potato root colonization.

    Science.gov (United States)

    Gallou, Adrien; Declerck, Stéphane; Cranenbrouck, Sylvie

    2012-03-01

    The establishment of arbuscular mycorrhizal associations causes major changes in plant roots and affects significantly the host in term of plant nutrition and resistance against biotic and abiotic stresses. As a consequence, major changes in root transcriptome, especially in plant genes related to biotic stresses, are expected. Potato microarray analysis, followed by real-time quantitative PCR, was performed to detect the wide transcriptome changes induced during the pre-, early and late stages of potato root colonization by Glomus sp. MUCL 41833. The microarray analysis revealed 526 up-regulated and 132 down-regulated genes during the pre-stage, 272 up-regulated and 109 down-regulated genes during the early stage and 734 up-regulated and 122 down-regulated genes during the late stage of root colonization. The most important class of regulated genes was associated to plant stress and in particular to the WRKY transcription factors genes during the pre-stage of root colonization. The expression profiling clearly demonstrated a wide transcriptional change during the pre-, early and late stages of root colonization. It further suggested that the WRKY transcription factor genes are involved in the mechanisms controlling the arbuscular mycorrhizal establishment by the regulation of plant defence genes.

  9. Lipochitooligosaccharides modulate plant host immunity to enable endosymbioses

    NARCIS (Netherlands)

    Limpens, E.H.M.; Zeijl, van A.L.; Geurts, R.

    2015-01-01

    Symbiotic nitrogen-fixing rhizobium bacteria and arbuscular mycorrhizal fungi use lipochitooligosaccharide (LCO) signals to communicate with potential host plants. Upon a compatible match, an intimate relation is established during which the microsymbiont is allowed to enter root (-derived) cells.

  10. ENERGY IN THE CONTEXT OF THE PRESENT CHALLENGES TO THE EUROPEAN COMMON SECURITY AND DEFENCE POLICY

    Directory of Open Access Journals (Sweden)

    Gabriel ANDRUSEAC

    2014-10-01

    Full Text Available The Common Security and Defence Policy is a part of the European Union’s Common Foreign and Security Policy (CFSP and establishes the policy framework for the institutional structures and military instruments which have to deal with the security challenges in Europe’s geopolitical neighborhood. The article aims to identify and analyze the role of energy as one of the present challenges to the European Common Security and Defence Policy in the context of the recent events in the world economy.

  11. DNA Damage Response and Immune Defence: Links and Mechanisms

    Directory of Open Access Journals (Sweden)

    Björn Schumacher

    2016-08-01

    Full Text Available DNA damage plays a causal role in numerous human pathologies including cancer, premature aging and chronic inflammatory conditions. In response to genotoxic insults, the DNA damage response (DDR orchestrates DNA damage checkpoint activation and facilitates the removal of DNA lesions. The DDR can also arouse the immune system by for example inducing the expression of antimicrobial peptides as well as ligands for receptors found on immune cells. The activation of immune signalling is triggered by different components of the DDR including DNA damage sensors, transducer kinases, and effectors. In this review, we describe recent advances on the understanding of the role of DDR in activating immune signalling. We highlight evidence gained into (i which molecular and cellular pathways of DDR activate immune signalling, (ii how DNA damage drives chronic inflammation, and (iii how chronic inflammation causes DNA damage and pathology in humans.

  12. Down-regulation of plant defence in a resident spider mite species and its effect upon con- and heterospecifics.

    Science.gov (United States)

    Godinho, Diogo P; Janssen, Arne; Dias, Teresa; Cruz, Cristina; Magalhães, Sara

    2016-01-01

    Herbivorous spider mites occurring on tomato plants (Solanum lycopersicum L.) cope with plant defences in various manners: the invasive Tetranychus evansi reduces defences below constitutive levels, whereas several strains of T. urticae induce such defences and others suppress them. In the Mediterranean region, these two species co-occur on tomato plants with T. ludeni, another closely related spider mite species. Unravelling how this third mite species affects plant defences is thus fundamental to understanding the outcome of herbivore interactions in this system. To test the effect of T. ludeni on tomato plant defences, we measured (1) the activity of proteinase inhibitors, indicating the induction of plant defences, in those plants, and (2) mite performance on plants previously infested with each mite species. We show that the performance of T. evansi and T. ludeni on plants previously infested with T. ludeni or T. evansi was better than on clean plants, indicating that these two mite species down-regulate plant defences. We also show that plants attacked by these mite species had lower activity of proteinase inhibitors than clean plants, whereas herbivory by T. urticae increased the activity of these proteins and resulted in reduced spider mite performance. This study thus shows that the property of down-regulation of plant defences below constitutive levels also occurs in T. ludeni.

  13. The association between self-image and defence mechanisms in a group of adolescent patients receiving psychiatric treatment.

    Science.gov (United States)

    Treger, Bartosz; Matusiak, Feliks; Pilecki, Maciej; Rogoż, Monika

    2015-01-01

    The aim of the study was to explore the relationship between various areas of self-image and defence mechanisms in adolescents. The study included a division into groups according to whether or not they were receiving psychiatric treatment. Data were obtained from two groups: a clinical group (30 persons), consisting of adolescent patients of the Adolescent Inpatient Ward of the Child and Adolescent Psychiatry Clinic and a control group (40 persons), adolescents attending upper secondary school. The Defence Style Questionnaire DSQ-40 and the Offer Self Image Questionnaire were used in the study. Results showed no differences, in the maturity levels of the defence mechanisms, between the two groups. Subjects from the clinical group had a significantly lower self-image of themselves than subjects from the control group.. In both groups, the use of mature defence mechanisms was accompanied by a positive self-image, while the use of less mature defence mechanisms was associated with a lower self-image. Comparison of the groups revealed different relationships between the aspects of self-image and used defence mechanisms, in particular the mechanism of projection. Number of significant correlations was greater in the clinical group. In the context of lower self-image, the study revealed the importance of such defence mechanisms as projection, acting out, somatization or schizoid fantasies. The obtained results seem to confirm a hypothesis that the assessment of the maturity of defence mechanisms in the period of adolescence is less clear and clinically useful.

  14. The Capsicum annuum class IV chitinase ChitIV interacts with receptor-like cytoplasmic protein kinase PIK1 to accelerate PIK1-triggered cell death and defence responses.

    Science.gov (United States)

    Kim, Dae Sung; Kim, Nak Hyun; Hwang, Byung Kook

    2015-04-01

    The pepper receptor-like cytoplasmic protein kinase, CaPIK1, which mediates signalling of plant cell death and defence responses was previously identified. Here, the identification of a class IV chitinase, CaChitIV, from pepper plants (Capsicum annuum), which interacts with CaPIK1 and promotes CaPIK1-triggered cell death and defence responses, is reported. CaChitIV contains a signal peptide, chitin-binding domain, and glycol hydrolase domain. CaChitIV expression was up-regulated by Xanthomonas campestris pv. vesicatoria (Xcv) infection. Notably, avirulent Xcv infection rapidly induced CaChitIV expression in pepper leaves. Bimolecular fluorescence complementation and co-immunoprecipitation revealed that CaPIK1 interacts with CaChitIV in planta, and that the CaPIK1-CaChitIV complex is localized mainly in the cytoplasm and plasma membrane. CaChitIV is also localized in the endoplasmic reticulum. Transient co-expression of CaChitIV with CaPIK1 enhanced CaPIK1-triggered cell death response and reactive oxygen species (ROS) and nitric oxide (NO) bursts. Co-silencing of both CaChitIV and CaPIK1 in pepper plants conferred enhanced susceptibility to Xcv infection, which was accompanied by a reduced induction of cell death response, ROS and NO bursts, and defence response genes. Ectopic expression of CaPIK1 in Arabidopsis enhanced basal resistance to Hyaloperonospora arabidopsidis infection. Together, the results suggest that CaChitIV positively regulates CaPIK1-triggered cell death and defence responses through its interaction with CaPIK1. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  15. Bovine lactoferrin counteracts Toll-like receptor mediated activation signals in antigen presenting cells.

    Directory of Open Access Journals (Sweden)

    Patrizia Puddu

    Full Text Available Lactoferrin (LF, a key element in mammalian immune system, plays pivotal roles in host defence against infection and excessive inflammation. Its protective effects range from direct antimicrobial activities against a large panel of microbes, including bacteria, viruses, fungi and parasites, to antinflammatory and anticancer activities. In this study, we show that monocyte-derived dendritic cells (MD-DCs generated in the presence of bovine LF (bLF fail to undergo activation by up-modulating CD83, co-stimulatory and major histocompatibility complex molecules, and cytokine/chemokine secretion. Moreover, these cells are weak activators of T cell proliferation and retain antigen uptake activity. Consistent with an impaired maturation, bLF-MD-DC primed T lymphocytes exhibit a functional unresponsiveness characterized by reduced expression of CD154 and impaired expression of IFN-γ and IL-2. The observed imunosuppressive effects correlate with an increased expression of molecules with negative regulatory functions (i.e. immunoglobulin-like transcript 3 and programmed death ligand 1, indoleamine 2,3-dioxygenase, and suppressor of cytokine signaling-3. Interestingly, bLF-MD-DCs produce IL-6 and exhibit constitutive signal transducer and activator of transcription 3 activation. Conversely, bLF exposure of already differentiated MD-DCs completely fails to induce IL-6, and partially inhibits Toll-like receptor (TLR agonist-induced activation. Cell-specific differences in bLF internalization likely account for the distinct response elicited by bLF in monocytes versus immature DCs, providing a mechanistic base for its multiple effects. These results indicate that bLF exerts a potent anti-inflammatory activity by skewing monocyte differentiation into DCs with impaired capacity to undergo activation and to promote Th1 responses. Overall, these bLF-mediated effects may represent a strategy to block excessive DC activation upon TLR-induced inflammation, adding

  16. Interaction of Medicago truncatula lysin motif receptor-like kinases, NFP and LYK3, produced in Nicotiana benthamiana induces defence-like responses.

    Directory of Open Access Journals (Sweden)

    Anna Pietraszewska-Bogiel

    Full Text Available Receptor(-like kinases with Lysin Motif (LysM domains in their extracellular region play crucial roles during plant interactions with microorganisms; e.g. Arabidopsis thaliana CERK1 activates innate immunity upon perception of fungal chitin/chitooligosaccharides, whereas Medicago truncatula NFP and LYK3 mediate signalling upon perception of bacterial lipo-chitooligosaccharides, termed Nod factors, during the establishment of mutualism with nitrogen-fixing rhizobia. However, little is still known about the exact activation and signalling mechanisms of MtNFP and MtLYK3. We aimed at investigating putative molecular interactions of MtNFP and MtLYK3 produced in Nicotiana benthamiana. Surprisingly, heterologous co-production of these proteins resulted in an induction of defence-like responses, which included defence-related gene expression, accumulation of phenolic compounds, and cell death. Similar defence-like responses were observed upon production of AtCERK1 in N. benthamiana leaves. Production of either MtNFP or MtLYK3 alone or their co-production with other unrelated receptor(-like kinases did not induce cell death in N. benthamiana, indicating that a functional interaction between these LysM receptor-like kinases is required for triggering this response. Importantly, structure-function studies revealed that the MtNFP intracellular region, specific features of the MtLYK3 intracellular region (including several putative phosphorylation sites, and MtLYK3 and AtCERK1 kinase activity were indispensable for cell death induction, thereby mimicking the structural requirements of nodulation or chitin-induced signalling. The observed similarity of N. benthamiana response to MtNFP and MtLYK3 co-production and AtCERK1 production suggests the existence of parallels between Nod factor-induced and chitin-induced signalling mediated by the respective LysM receptor(-like kinases. Notably, the conserved structural requirements for MtNFP and MtLYK3 biological

  17. Interaction of Medicago truncatula lysin motif receptor-like kinases, NFP and LYK3, produced in Nicotiana benthamiana induces defence-like responses.

    Science.gov (United States)

    Pietraszewska-Bogiel, Anna; Lefebvre, Benoit; Koini, Maria A; Klaus-Heisen, Dörte; Takken, Frank L W; Geurts, René; Cullimore, Julie V; Gadella, Theodorus W J

    2013-01-01

    Receptor(-like) kinases with Lysin Motif (LysM) domains in their extracellular region play crucial roles during plant interactions with microorganisms; e.g. Arabidopsis thaliana CERK1 activates innate immunity upon perception of fungal chitin/chitooligosaccharides, whereas Medicago truncatula NFP and LYK3 mediate signalling upon perception of bacterial lipo-chitooligosaccharides, termed Nod factors, during the establishment of mutualism with nitrogen-fixing rhizobia. However, little is still known about the exact activation and signalling mechanisms of MtNFP and MtLYK3. We aimed at investigating putative molecular interactions of MtNFP and MtLYK3 produced in Nicotiana benthamiana. Surprisingly, heterologous co-production of these proteins resulted in an induction of defence-like responses, which included defence-related gene expression, accumulation of phenolic compounds, and cell death. Similar defence-like responses were observed upon production of AtCERK1 in N. benthamiana leaves. Production of either MtNFP or MtLYK3 alone or their co-production with other unrelated receptor(-like) kinases did not induce cell death in N. benthamiana, indicating that a functional interaction between these LysM receptor-like kinases is required for triggering this response. Importantly, structure-function studies revealed that the MtNFP intracellular region, specific features of the MtLYK3 intracellular region (including several putative phosphorylation sites), and MtLYK3 and AtCERK1 kinase activity were indispensable for cell death induction, thereby mimicking the structural requirements of nodulation or chitin-induced signalling. The observed similarity of N. benthamiana response to MtNFP and MtLYK3 co-production and AtCERK1 production suggests the existence of parallels between Nod factor-induced and chitin-induced signalling mediated by the respective LysM receptor(-like) kinases. Notably, the conserved structural requirements for MtNFP and MtLYK3 biological activity in M

  18. Creatine-induced activation of antioxidative defence in myotube cultures revealed by explorative NMR-based metabonomics and proteomics

    Directory of Open Access Journals (Sweden)

    Nielsen Niels

    2010-02-01

    Full Text Available Abstract Background Creatine is a key intermediate in energy metabolism and supplementation of creatine has been used for increasing muscle mass, strength and endurance. Creatine supplementation has also been reported to trigger the skeletal muscle expression of insulin like growth factor I, to increase the fat-free mass and improve cognition in elderly, and more explorative approaches like transcriptomics has revealed additional information. The aim of the present study was to reveal additional insight into the biochemical effects of creatine supplementation at the protein and metabolite level by integrating the explorative techniques, proteomics and NMR metabonomics, in a systems biology approach. Methods Differentiated mouse myotube cultures (C2C12 were exposed to 5 mM creatine monohydrate (CMH for 24 hours. For proteomics studies, lysed myotubes were analyzed in single 2-DGE gels where the first dimension of protein separation was pI 5-8 and second dimension was a 12.5% Criterion gel. Differentially expressed protein spots of significance were excised from the gel, desalted and identified by peptide mass fingerprinting using MALDI-TOF MS. For NMR metabonomic studies, chloroform/methanol extractions of the myotubes were subjected to one-dimensional 1H NMR spectroscopy and the intracellular oxidative status of myotubes was assessed by intracellular DCFH2 oxidation after 24 h pre-incubation with CMH. Results The identified differentially expressed proteins included vimentin, malate dehydrogenase, peroxiredoxin, thioredoxin dependent peroxide reductase, and 75 kDa and 78 kDa glucose regulated protein precursors. After CMH exposure, up-regulated proteomic spots correlated positively with the NMR signals from creatine, while down-regulated proteomic spots were negatively correlated with these NMR signals. The identified differentially regulated proteins were related to energy metabolism, glucose regulated stress, cellular structure and the

  19. CYP94-mediated jasmonoyl-isoleucine hormone oxidation shapes jasmonate profiles and attenuates defence responses to Botrytis cinerea infection

    Science.gov (United States)

    Aubert, Yann; Widemann, Emilie; Miesch, Laurence; Pinot, Franck; Heitz, Thierry

    2015-01-01

    Induced resistance to the necrotrophic pathogen Botrytis cinerea depends on jasmonate metabolism and signalling in Arabidopsis. We have presented here extensive jasmonate profiling in this pathosystem and investigated the impact of the recently reported jasmonoyl-isoleucine (JA-Ile) catabolic pathway mediated by cytochrome P450 (CYP94) enzymes. Using a series of mutant and overexpressing (OE) plant lines, we showed that CYP94B3 and CYP94C1 are integral components of the fungus-induced jasmonate metabolic pathway and control the abundance of oxidized conjugated but also some unconjugated derivatives, such as sulfated 12-HSO4-JA. Despite causing JA-Ile overaccumulation due to impaired oxidation, CYP94 deficiency had negligible impacts on resistance, associated with enhanced JAZ repressor transcript levels. In contrast, plants overexpressing (OE) CYP94B3 or CYP94C1 were enriched in 12-OH-JA-Ile or 12-COOH-JA-Ile respectively. This shift towards oxidized JA-Ile derivatives was concomitant with strongly impaired defence gene induction and reduced disease resistance. CYP94B3-OE, but unexpectedly not CYP94C1-OE, plants displayed reduced JA-Ile levels compared with the wild type, suggesting that increased susceptibility in CYP94C1-OE plants may result from changes in the hormone oxidation ratio rather than absolute changes in JA-Ile levels. Consistently, while feeding JA-Ile to seedlings triggered strong induction of JA pathway genes, induction was largely reduced or abolished after feeding with the CYP94 products 12-OH-JA-Ile and 12-COOH-JA-Ile, respectively. This trend paralleled in vitro pull-down assays where 12-COOH-JA-Ile was unable to promote COI1–JAZ9 co-receptor assembly. Our results highlight the dual function of CYP94B3/C1 in antimicrobial defence: by controlling hormone oxidation status for signal attenuation, these enzymes also define JA-Ile as a metabolic hub directing jasmonate profile complexity. PMID:25903915

  20. Molecular and Cellular Signaling

    CERN Document Server

    Beckerman, Martin

    2005-01-01

    A small number of signaling pathways, no more than a dozen or so, form a control layer that is responsible for all signaling in and between cells of the human body. The signaling proteins belonging to the control layer determine what kinds of cells are made during development and how they function during adult life. Malfunctions in the proteins belonging to the control layer are responsible for a host of human diseases ranging from neurological disorders to cancers. Most drugs target components in the control layer, and difficulties in drug design are intimately related to the architecture of the control layer. Molecular and Cellular Signaling provides an introduction to molecular and cellular signaling in biological systems with an emphasis on the underlying physical principles. The text is aimed at upper-level undergraduates, graduate students and individuals in medicine and pharmacology interested in broadening their understanding of how cells regulate and coordinate their core activities and how diseases ...

  1. The current Salmonella–host interactome

    Science.gov (United States)

    Schleker, Sylvia; Sun, Jingchun; Raghavan, Balachandran; Srnec, Matthew; Müller, Nicole; Koepfinger, Mary; Murthy, Leelavati; Zhao, Zhongming; Klein-Seetharaman, Judith

    2011-01-01

    Salmonella bacteria cause millions of infections and thousands of deaths every year. This pathogen has an unusually broad host range including humans, animals, and even plants. During infection, Salmonella expresses a variety of virulence factors and effectors that are delivered into the host cell triggering cellular responses through protein–protein interactions (PPIs) with host cell proteins which make the pathogen’s invasion and replication possible. To speed up proteomic efforts in elucidating Salmonella–host interactomes, we carried out a survey of the currently published Salmonella–host PPI. Such a list can serve as the gold standard for computational models aimed at predicting Salmonella–host interactomes through integration of large-scale biological data sources. Manual literature and database search of >2200 journal articles and >100 databases resulted in a gold standard list of currently 62 PPI, including primarily interactions of Salmonella proteins with human and mouse proteins. Only six of these interactions were directly retrievable from PPI databases and 16 were highlighted in databases featuring literature extracts. Thus, the literature survey resulted in the most complete interactome available to date for Salmonella. Pathway analysis using Ingenuity and Broad Gene Set Enrichment Analysis (GSEA) software revealed among general pathways such as MAPK signaling in particular those related to cell death as well as cell morphology, turnover, and interactions, in addition to response to not only Salmonella but also other pathogenic – viral and bacterial – infections. The list of interactions is available at http://www.shiprec.org/indicationslist.htm PMID:22213674

  2. Parasitism by Cuscuta pentagona sequentially induces JA and SA defence pathways in tomato

    Science.gov (United States)

    Justin B. Runyon; Mark C. Mescher; Gary W. Felton; Consuelo M. De Moraes

    2010-01-01

    While plant responses to herbivores and pathogens are well characterized, responses to attack by other plants remain largely unexplored. We measured phytohormones and C18 fatty acids in tomato attacked by the parasitic plant Cuscuta pentagona, and used transgenic and mutant plants to explore the roles of the defence-related phytohormones salicylic...

  3. The Australian Defence Force Mental Health Prevalence and Wellbeing Study: design and methods.

    NARCIS (Netherlands)

    Hooff, M.V.; McFarlane, A.C.; Davies, C.E.; Searle, A.K.; Fairweather-Schmidt, A.K.; Verhagen, A.F.; Benassi, H.; Hodson, S.E.

    2014-01-01

    BACKGROUND: The Australian Defence Force (ADF) Mental Health Prevalence and Wellbeing Study (MHPWS) is the first study of mental disorder prevalence in an entire military population. OBJECTIVE: The MHPWS aims to establish mental disorder prevalence, refine current ADF mental health screening

  4. The Immune System and Bodily Defence-How Does the Immune ...

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 3; Issue 1. The Immune System and Bodily Defence - How Does the Immune System Live With a Randomly Generated Repertoire? Vineeta Bal Satyajit Rath. Series Article Volume 3 Issue 1 January 1998 pp 15-20 ...

  5. Christina Isajiw. Negotiating Human Rights: In Defence of Dissidents during the Soviet Era. A Memoir.

    Directory of Open Access Journals (Sweden)

    Barbara Martin

    2015-09-01

    Full Text Available Christina Isajiw. Negotiating Human Rights: In Defence of Dissidents during the Soviet Era. A Memoir. Edmonton and Toronto: Canadian Institute of Ukrainian Studies Press, 2014. xxx, 407 pp. Foreword by Bohdan Nahaylo. Introduction. Illustrations. Appendices on separate CD-Rom. Index. Paper.

  6. The Party Politics of Legislative-Executive Relations in Security and Defence Policy

    NARCIS (Netherlands)

    Wagner, W.M.; Herranz-Surralles, A.; Kaarbo, J.; Ostermann, F.

    2017-01-01

    The move from territorial defence to ‘wars of choice’ has influenced the domestic politics of military interventions. This paper examines the extent to which both the substance and the procedure of military interventions are contested among political parties. Regarding the substance, our analysis of

  7. M-ficolin, an innate immune defence molecule, binds patterns of acetyl groups and activates complement

    DEFF Research Database (Denmark)

    Frederiksen, Pernille Dorthea; Thiel, Steffen; Larsen, Claus Bindslev

    2005-01-01

    Ficolins play a role in the innate immune defence as pathogen-associated molecular pattern recognition molecules. Three ficolins are found in humans: H-ficolin, L-ficolin and M-ficolin. L-ficolin and H-ficolin circulate in blood in complexes with mannan-binding lectin-associated serine proteases...

  8. Quantifying police officers' arrest and self-defence skills: Does performance decrease under pressure?

    NARCIS (Netherlands)

    Nieuwenhuys, A.; Caljouw, S.R.; Leijsen, M.R.; Schmeits, B.A.J.; Oudejans, R.R.D.

    2009-01-01

    This study investigated police officers' performance on five selected arrest and self-defence skills that are regularly used in the line of duty. In Experiment 1 a 5-point scale to measure skill performance was developed and tested with 14 police instructors. Results showed that the new scale has

  9. A SIIORT IIISTORY OF FORT W'YNYAIID. TABLE BAY DEFENCES

    African Journals Online (AJOL)

    coastal defences at home and abroad foresaw danger from long range bombardment by battleships or heavy cruisers, 'bombardment at medium range by light cruisers', the attempted destruction of naval obstructions or the blocking of port or harbour entrances and night attacks by torpedo-craft. To counter these threats four ...

  10. The defence architecture of the superficial cells of the oral mucosa

    NARCIS (Netherlands)

    Asikainen, P.; Ruotsalainen, T.J.; Mikkonen, J.J.W.; Koistinen, A.; ten Bruggenkate, C.; Kullaa, A.M.

    2012-01-01

    The oral epithelium together with the saliva and its components forms a complex structure which is the first line of defence in the oral cavity. The surface of superficial cells of the oral epithelium contains ridge-like folds, microplicae (MPL), which are typical of the surfaces of areas covered

  11. Previous stress and acute psychological defence as predictors of perinatal grief - An exploratory study

    NARCIS (Netherlands)

    J.A.M. Hunfeld (Joke); J.W. Wladimiroff (Juriy); F. Verhage; J. Passchier (Jan)

    1995-01-01

    textabstractWe evaluated whether the emotional reactions of women at 2–6 weeks after the prenatal diagnosis of a lethal anomaly and at 3 months after perinatal loss might be predicted by previous stress and acute psychological defence reactions to the diagnosis. Previous stress was defined

  12. Fitness consequences of indirect plant defence in the annual weed, Sinapis arvensis

    NARCIS (Netherlands)

    Gols, R.; Wagenaar, R.; Poelman, E.H.; Kruidhof, H.M.; Loon, van J.J.A.; Harvey, J.A.

    2015-01-01

    Plant traits that enhance the attraction of the natural enemies of their herbivores have been postulated to function as an 'indirect defence'. An important underlying assumption is that this enhanced attraction results in increased plant fitness due to reduced herbivory. This assumption has been

  13. Evidence of a causal connection between anti-herbivore defence and the decomposition rate of leaves

    NARCIS (Netherlands)

    Grime, J. Philip; Cornelissen, J. H.C.; Thompson, Ken; Hodgson, John G.

    1996-01-01

    An experiment was conducted to test the hypothesis that interspecific variation in rates of leaf litter decomposition arises as a consequence of differences in the anti-herbivore defences of the living leaf. Leaf palatability was assayed in 54 vascular plant species of widespread occurrence in the

  14. Male Rock Sparrow (Petronia petronia) Nest Defence Correlates with Female Ornament Size

    DEFF Research Database (Denmark)

    Griggio, Matteo; Matessi, Giuliano; Pilastro, Andrea

    2003-01-01

    We investigated the relationship between male nest defence and female breast patch size in an alpine population of rock sparrow (Petronia petronia) in northern Italy. We presented a mounted weasel (Mustela nivalis), a common nest predator, to 28 pairs breeding in nest boxes, with 12-13-d-old nest...

  15. Civil Defence Pedagogies and Narratives of Democracy: Disaster Education in Germany

    Science.gov (United States)

    Chadderton, Charlotte

    2015-01-01

    "Disaster education" is a fledgling area of study in lifelong education. Many countries educate their populations for disasters, to mitigate potential damage and loss of life, as well as contribute to national security. In this paper, which draws on interview data from the German Federal Office for Civil Defence and Disaster Assistance…

  16. Russia's hybrid war and its implications for defence and security in ...

    African Journals Online (AJOL)

    Russia's hybrid war and its implications for defence and security in the United Kingdom. ... Scientia Militaria: South African Journal of Military Studies ... This article uses the example of Russia's aggressive action against Ukraine as an example of a new form of contemporary war fighting, namely hybrid war, and discusses ...

  17. The effect of inbreeding on defence against multiple enemies in Datura stramonium.

    Science.gov (United States)

    Bello-Bedoy, R; Núñez-Farfán, J

    2011-03-01

    The ability of plants to respond to natural enemies might depend on the availability of genetic variation for the optimal phenotypic expression of defence. Selfing can affect the distribution of genetic variability of plant fitness, resistance and tolerance to herbivores and pathogens. The hypothesis of inbreeding depression influencing plant defence predicts that inbreeding would reduce resistance and tolerance to damage by natural enemies relative to outcrossing. In a field experiment entailing experimentally produced inbred and outcrossed progenies, we assessed the effects of one generation of selfing on Datura stramonium resistance and tolerance to three types of natural enemies, herbivores, weevils and a virus. We also examined the effect of damage on relative growth rate (RGR), flower, fruit, and seed production in inbred and outcrossed plants. Inbreeding significantly reduced plant defence to natural enemies with an increase of 4% in herbivore damage and 8% in viral infection. These results indicate inbreeding depression in total resistance. Herbivory increased 10% inbreeding depression in seed number, but viral damage caused inbred and outcrossed plants to have similar seed production. Inbreeding and outcrossing effects on fitness components were highly variable among families, implying that different types or numbers of recessive deleterious alleles segregate following inbreeding in D. stramonium. Although inbreeding did not equally alter all the interactions, our findings indicate that inbreeding reduced plant defence to herbivores and pathogens in D. stramonium. © 2010 The Authors. Journal of Evolutionary Biology © 2010 European Society For Evolutionary Biology.

  18. Responses of foliar antioxidative and photoprotective defence systems of trees to drought: a meta-analysis.

    Science.gov (United States)

    Wujeska, Agnieszka; Bossinger, Gerd; Tausz, Michael

    2013-10-01

    Current climate change predictions hint to more frequent extreme weather events, including extended droughts, making better understanding of the impacts of water stress on trees even more important. At the individual plant level, stomatal closure as a result of water deficit leads to reduced CO2 availability in the leaf, which can lead to photo-oxidative stress. Photorespiration and the Mehler reaction can maintain electron transport rates under low internal CO2, but result in production of reactive oxygen species (ROS). If electron consumption is decreased, upstream photochemical processes can be affected and light energy is absorbed in excess of photochemical requirements. Trees evolved to cope with excess energy and elevated concentration of ROS by activating photoprotective and antioxidative defence systems. The meta-analysis we present here assessed responses of these defence systems reported in 50 studies. We found responses to vary depending on stress intensity, foliage type and habitat, and on whether experiments were done in the field or in controlled environments. In general, drought increased concentrations of antioxidants and photoprotective pigments. However, severe stress caused degradation of antioxidant concentrations and oxidation of antioxidant pools. Evergreen trees seemed to preferentially reinforce membrane-bound protection systems zeaxanthin and tocopherol, whereas deciduous species showed greater responses in water-soluble antioxidants ascorbic acid and glutathione. Trees and shrubs from arid versus humid habitats vary in their antioxidative and photoprotective defence responses. In field experiments, drought had greater effects on some defence compounds than under controlled conditions.

  19. Describing joint air defence within operations other than war context as a complex system

    CSIR Research Space (South Africa)

    Oosthuizen, R

    2009-10-01

    Full Text Available The objective of Joint Air Defence (JAD) is to defend own assets against all types of hostile aerial attack. This may even happen within the context of Operations Other Than War (OOTW). Like general warfare, OOTW is a complex environment where...

  20. The ‘Unwilling or Unable’ Test and the Law of Self-defence

    NARCIS (Netherlands)

    Tibori-Szabó, K.; Paulussen, C.; Takács, T.; Lazić, V.; Van Rompuy, B.

    2015-01-01

    Recent events related to the rise of ISIS have catapulted the ‘unwilling or unable’ test to the forefront of the legal debate concerning the fight against terrorism. The still controversial test offers a justification for unilateral use of force in self-defence on behalf of a victim state on the