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Sample records for activate defense mechanisms

  1. Activation of Defense Mechanisms against Pathogens in Mosses and Flowering Plants

    PubMed Central

    de León, Inés Ponce; Montesano, Marcos

    2013-01-01

    During evolution, plants have developed mechanisms to cope with and adapt to different types of stress, including microbial infection. Once the stress is sensed, signaling pathways are activated, leading to the induced expression of genes with different roles in defense. Mosses (Bryophytes) are non-vascular plants that diverged from flowering plants more than 450 million years ago, allowing comparative studies of the evolution of defense-related genes and defensive metabolites produced after microbial infection. The ancestral position among land plants, the sequenced genome and the feasibility of generating targeted knock-out mutants by homologous recombination has made the moss Physcomitrella patens an attractive model to perform functional studies of plant genes involved in stress responses. This paper reviews the current knowledge of inducible defense mechanisms in P. patens and compares them to those activated in flowering plants after pathogen assault, including the reinforcement of the cell wall, ROS production, programmed cell death, activation of defense genes and synthesis of secondary metabolites and defense hormones. The knowledge generated in P. patens together with comparative studies in flowering plants will help to identify key components in plant defense responses and to design novel strategies to enhance resistance to biotic stress. PMID:23380962

  2. Activation of Defense Mechanisms against Pathogens in Mosses and Flowering Plants.

    PubMed

    Ponce de León, Inés; Montesano, Marcos

    2013-02-04

    During evolution, plants have developed mechanisms to cope with and adapt to different types of stress, including microbial infection. Once the stress is sensed, signaling pathways are activated, leading to the induced expression of genes with different roles in defense. Mosses (Bryophytes) are non-vascular plants that diverged from flowering plants more than 450 million years ago, allowing comparative studies of the evolution of defense-related genes and defensive metabolites produced after microbial infection. The ancestral position among land plants, the sequenced genome and the feasibility of generating targeted knock-out mutants by homologous recombination has made the moss Physcomitrella patens an attractive model to perform functional studies of plant genes involved in stress responses. This paper reviews the current knowledge of inducible defense mechanisms in P. patens and compares them to those activated in flowering plants after pathogen assault, including the reinforcement of the cell wall, ROS production, programmed cell death, activation of defense genes and synthesis of secondary metabolites and defense hormones. The knowledge generated in P. patens together with comparative studies in flowering plants will help to identify key components in plant defense responses and to design novel strategies to enhance resistance to biotic stress.

  3. Understanding Defense Mechanisms.

    PubMed

    Cramer, Phebe

    2015-12-01

    Understanding defense mechanisms is an important part of psychotherapy. In this article, we trace the history of the concept of defense, from its origin with Freud to current views. The issue of defense as an unconscious mechanism is examined. The question of whether defenses are pathological, as well as their relation to pathology, is discussed. The effect of psychotherapy on the use of defenses, and their relation to a therapeutic alliance is explored. A series of empirical research studies that demonstrate the functioning of defense mechanisms and that support the theory is presented. Research also shows that as part of normal development, different defenses emerge at different developmental periods, and that gender differences in defense use occur.

  4. Defense Mechanisms: A Bibliography.

    ERIC Educational Resources Information Center

    Pedrini, D. T.; Pedrini, Bonnie C.

    This bibliography includes studies of defense mechanisms, in general, and studies of multiple mechanisms. Defense mechanisms, briefly and simply defined, are the unconscious ego defendants against unpleasure, threat, or anxiety. Sigmund Freud deserves the clinical credit for studying many mechanisms and introducing them in professional literature.…

  5. Activation of Host Defense Mechanisms by Elevated Production of H2O2 in Transgenic Plants.

    PubMed Central

    Wu, G.; Shortt, B. J.; Lawrence, E. B.; Leon, J.; Fitzsimmons, K. C.; Levine, E. B.; Raskin, I.; Shah, D. M.

    1997-01-01

    Active oxygen species have been postulated to perform multiple functions in plant defense, but their exact role in plant resistance to diseases is not fully understood. We have recently demonstrated H2O2-mediated disease resistance in transgenic potato (Solanum tuberosum) plants expressing a foreign gene encoding glucose oxidase. In this study we provide further evidence that the H2O2-mediated disease resistance in potato is effective against a broad range of plant pathogens. We have investigated mechanisms underlying the H2O2-mediated disease resistance in transgenic potato plants. The constitutively elevated levels of H2O2 induced the accumulation of total salicylic acid severalfold in the leaf tissue of transgenic plants, although no significant change was detected in the level of free salicylic acid. The mRNAs of two defense-related genes encoding the anionic peroxidase and acidic chitinase were also induced. In addition, an increased accumulation of several isoforms of extracellular peroxidase, including a newly induced one, was observed. This was accompanied by a significant increase in the lignin content of stem and root tissues of the transgenic plants. The results suggest that constitutively elevated sublethal levels of H2O2 are sufficient to activate an array of host defense mechanisms, and these defense mechanisms may be a major contributing factor to the H2O2-mediated disease resistance in transgenic plants. PMID:12223817

  6. Natural host defense mechanisms.

    PubMed

    Heggers, J P

    1979-10-01

    Severe injury, whether the result of a major accident, a large burn, or a complicated surgical operation, often results in sepsis. Under such conditions both specific and nonspecific host defense systems are affected. The individual facets of major concern are chemotaxis, phagocytosis, intracellular killing, complement depletion, and depression of humoral and cellular mediated immunity. The most profound changes occur in cell-mediated immunity. Within a few hours o injury, the number of circulating T cells becomes depleted, concomitantly thoracic duct lymphocytes are markedly reduced. This change is not only quantitative but functional. The clinical impact of these deficient host defense mechanisms lies in the fact that low virulent organisms may become a lethal threat to the injured patient. Currently, investigators are attempting to reverse thse deficiencies through the use of immunotherapy.

  7. Gastroduodenal Mucosal Defense Mechanisms

    PubMed Central

    Said, Hyder; Kaji, Izumi; Kaunitz, Jonathan D.

    2015-01-01

    Purpose of Review To highlight recent developments in the field of gastroduodenal mucosal defense with emphasis on lumen-gut interactions. Recent Findings There has been a growing interest in the physiological functions of luminal chemosensors present from tongue to colon that detect organic molecules in the luminal content associated with nutrient ingestion, usually associated with specialized cells, in particular the enteroendocrine cells. These receptors transduce the release of peptide hormones, in particular proglucagon-derived products such as the glucagon-like-peptides (GLPs), which have profound effects on gut function and on metabolism. Luminal chemosensors transduce GLP release in response to changes in the cellular environment, as part of the mechanism of nutrient chemosensing. GLP-2 has important trophic effects on the intestinal mucosa, including increasing the proliferation rate of stem cells and reducing transmucosal permeability to ions and small molecules, in addition to increasing the rate of duodenal bicarbonate secretion. GLP-1, although traditionally considered an incretin that enhances the effect of insulin on peripheral tissues, also has trophic effects on the intestinal epithelium. Summary A better understanding of the mechanisms that mediate GLP release can further illuminate the importance of nutrient chemosensing as an important component of the mechanism that mediates the trophic effects of luminal nutrients. GLP-1 and -2 are already in clinical use for the treatment of diabetes and intestinal failure. Improved understanding of the control of their release and their end-organ effects will identify new clinical indications and interventions that enhance their release. PMID:26376476

  8. Control Processes and Defense Mechanisms

    PubMed Central

    HOROWITZ, MARDI; COOPER, STEVEN; FRIDHANDLER, BRAM; PERRY, J. CHRISTOPHER; BOND, MICHAEL; VAILLANT, GEORGE

    1992-01-01

    Defense-mechanism theory and control-process theory are related psychodynamic approaches to explaining and classifying how people ward off emotional upsets. Although both theories explain defensive maneuvers in the same motivational terms, each defines categories different1y. Classic categories define defense mechanisms at a relatively macroscopic level, whereas control-process theory aims at relatively microgenetic analysis of how cognitive maneuvers—involving what is thought, how it is thought, and how it is organized—may generate defensive states. The theories are not contradictory, but they are focused on different levels of observation; it is useful to compare how these classifications are applied to specific case material. PMID:22700114

  9. Plant storage proteins with antimicrobial activity: novel insights into plant defense mechanisms.

    PubMed

    Cândido, Elizabete de Souza; Pinto, Michelle Flaviane Soares; Pelegrini, Patrícia Barbosa; Lima, Thais Bergamin; Silva, Osmar Nascimento; Pogue, Robert; Grossi-de-Sá, Maria Fátima; Franco, Octávio Luiz

    2011-10-01

    Storage proteins perform essential roles in plant survival, acting as molecular reserves important for plant growth and maintenance, as well as being involved in defense mechanisms by virtue of their properties as insecticidal and antimicrobial proteins. These proteins accumulate in storage vacuoles inside plant cells, and, in response to determined signals, they may be used by the different plant tissues in response to pathogen attack. To shed some light on these remarkable proteins with dual functions, storage proteins found in germinative tissues, such as seeds and kernels, and in vegetative tissues, such as tubercles and leaves, are extensively discussed here, along with the related mechanisms of protein expression. Among these proteins, we focus on 2S albumins, Kunitz proteinase inhibitors, plant lectins, glycine-rich proteins, vicilins, patatins, tarins, and ocatins. Finally, the potential use of these molecules in development of drugs to combat human and plant pathogens, contributing to the development of new biotechnology-based medications and products for agribusiness, is also presented.

  10. Caspase-8 activity is part of the BeWo trophoblast cell defense mechanisms against Trypanosoma cruzi infection.

    PubMed

    Carrillo, Ileana; Droguett, Daniel; Castillo, Christian; Liempi, Ana; Muñoz, Lorena; Maya, Juan Diego; Galanti, Norbel; Kemmerling, Ulrike

    2016-09-01

    Congenital Chagas disease is caused by the protozoan parasite Trypanosoma cruzi that must cross the placental barrier during transmission. The trophoblast constitutes the first tissue in contact with the maternal-blood circulating parasite. Importantly, the congenital transmission rates are low, suggesting the presence of local placental defense mechanisms. Cellular proliferation and differentiation as well as apoptotic cell death are induced by the parasite and constitute part of the epithelial turnover of the trophoblast, which has been suggested to be part of those placental defenses. On the other hand, caspase-8 is an essential molecule in the modulation of trophoblast turnover by apoptosis and by epithelial differentiation. As an approach to study whether T. cruzi induced trophoblast turnover and infection is mediated by caspase-8, we infected BeWo cells (a trophoblastic cell line) with the parasite and determined in the infected cells the expression and enzymatic activity of caspase-8, DNA synthesis (as proliferation marker), β-human chorionic gonadotropin (β-hCG) (as differentiation marker) and activity of Caspase-3 (as apoptotic death marker). Parasite load in BeWo cells was measured by DNA quantification using qPCR and cell counting. Our results show that T. cruzi induces caspase-8 activity and that its inhibition increases trophoblast cells infection while decreases parasite induced cellular differentiation and apoptotic cell death, but not cellular proliferation. Thus, caspase-8 activity is part of the BeWo trophoblast cell defense mechanisms against T. cruzi infection. Together with our previous results, we suggest that the trophoblast turnover is part of local placental anti-parasite mechanisms.

  11. Prevalence and Mechanisms of Dynamic Chemical Defenses in Tropical Sponges

    PubMed Central

    Rohde, Sven; Nietzer, Samuel; Schupp, Peter J.

    2015-01-01

    Sponges and other sessile invertebrates are lacking behavioural escape or defense mechanisms and rely therefore on morphological or chemical defenses. Studies from terrestrial systems and marine algae demonstrated facultative defenses like induction and activation to be common, suggesting that sessile marine organisms also evolved mechanisms to increase the efficiency of their chemical defense. However, inducible defenses in sponges have not been investigated so far and studies on activated defenses are rare. We investigated whether tropical sponge species induce defenses in response to artificial predation and whether wounding triggers defense activation. Additionally, we tested if these mechanisms are also used to boost antimicrobial activity to avoid bacterial infection. Laboratory experiments with eight pacific sponge species showed that 87% of the tested species were chemically defended. Two species, Stylissa massa and Melophlus sarasinorum, induced defenses in response to simulated predation, which is the first demonstration of induced antipredatory defenses in marine sponges. One species, M. sarasinorum, also showed activated defense in response to wounding. Interestingly, 50% of the tested sponge species demonstrated induced antimicrobial defense. Simulated predation increased the antimicrobial defenses in Aplysinella sp., Cacospongia sp., M. sarasinorum, and S. massa. Our results suggest that wounding selects for induced antimicrobial defenses to protect sponges from pathogens that could otherwise invade the sponge tissue via feeding scars. PMID:26154741

  12. Mechanisms of defense: development and research perspectives.

    PubMed

    Kernberg, P F

    1994-01-01

    The author offers a selective overview of defense mechanisms. With an eye to clarifying the definition of defense mechanisms and the use of this concept in treatment, she traces the evolution of the concept since its initial formulation, examines the developmental aspects of defenses and the implications for psychopathology, and discusses various recent research studies.

  13. Rock mechanics contributions from defense programs

    SciTech Connect

    Heuze, F.E.

    1992-02-01

    An attempt is made at illustrating the many contributions to rock mechanics from US defense programs, over the past 30-plus years. Large advances have been achieved in the technology-base area covering instrumentation, material properties, physical modeling, constitutive relations and numerical simulations. In the applications field, much progress has been made in understanding and being able to predict rock mass behavior related to underground explosions, cratering, projectile penetration, and defense nuclear waste storage. All these activities stand on their own merit as benefits to national security. But their impact is even broader, because they have found widespread applications in the non-defense sector; to name a few: the prediction of the response of underground structures to major earthquakes, the physics of the earth`s interior at great depths, instrumentation for monitoring mine blasting, thermo-mechanical instrumentation useful for civilian nuclear waste repositories, dynamic properties of earthquake faults, and transient large-strain numerical modeling of geological processes, such as diapirism. There is not pretense that this summary is exhaustive. It is meant to highlight success stories representative of DOE and DOD geotechnical activities, and to point to remaining challenges.

  14. Lysozyme- and chitinase activity in latex bearing plants of genus Euphorbia--A contribution to plant defense mechanism.

    PubMed

    Sytwala, Sonja; Günther, Florian; Melzig, Matthias F

    2015-10-01

    Occurrence of latices in plants is widespread, there are 40 families of plants characterized to establish lactiferous structures. Latices exhibit a constitutive part of plant defense due to the stickiness. The appearance of proteins incorporated in latices is well characterized, and hydrolytic active proteins are considerable. A lot of plants constitute so-called pathogenesis-related (PR) proteins, to overcome stressful conditions. In our investigation we are focused on latex bearing plants of Euphorbiaceae Juss., and investigated the appearance of chitinase- and lysozyme activity in particular. The present outcomes represent a comprehensive study, relating to the occurrence of lysozyme and chitinase activity of genus Euphorbia at the first time. 110 different species of genus Euphorbia L. were tested, and the appearance of chitinase and lysozyme were determined in different quantities. The appearance itself, and the physicochemical properties of latices indicate an efficient interaction for plant defense against pathogen attack.

  15. Cell senescence is an antiviral defense mechanism

    PubMed Central

    Baz-Martínez, Maite; Da Silva-Álvarez, Sabela; Rodríguez, Estefanía; Guerra, Jorge; El Motiam, Ahmed; Vidal, Anxo; García-Caballero, Tomás; González-Barcia, Miguel; Sánchez, Laura; Muñoz-Fontela, César; Collado, Manuel; Rivas, Carmen

    2016-01-01

    Cellular senescence is often considered a protection mechanism triggered by conditions that impose cellular stress. Continuous proliferation, DNA damaging agents or activated oncogenes are well-known activators of cell senescence. Apart from a characteristic stable cell cycle arrest, this response also involves a proinflammatory phenotype known as senescence-associated secretory phenotype (SASP). This, together with the widely known interference with senescence pathways by some oncoviruses, had led to the hypothesis that senescence may also be part of the host cell response to fight virus. Here, we evaluate this hypothesis using vesicular stomatitis virus (VSV) as a model. Our results show that VSV replication is significantly impaired in both primary and tumor senescent cells in comparison with non-senescent cells, and independently of the stimulus used to trigger senescence. Importantly, we also demonstrate a protective effect of senescence against VSV in vivo. Finally, our results identify the SASP as the major contributor to the antiviral defense exerted by cell senescence in vitro, and points to a role activating and recruiting the immune system to clear out the infection. Thus, our study indicates that cell senescence has also a role as a natural antiviral defense mechanism. PMID:27849057

  16. Protecting the Self: Defense Mechanisms in Action

    ERIC Educational Resources Information Center

    Cramer, Phebe

    2006-01-01

    Integrating theory, research, and practical applications, this book provides a comprehensive examination of defense mechanisms and their role in both normal development and psychopathology. The author describes how children and adults mobilize specific kinds of defenses to maintain their psychological equilibrium and preserve self-esteem,…

  17. The Defense Mechanisms of Coronary Patients.

    ERIC Educational Resources Information Center

    Peglar, Marian; Borgen, Fred H.

    1984-01-01

    Tested 73 male inpatients with coronary heart disease on the Defense Mechanisms Inventory, State-Trait Anxiety Inventory, and a perception of health measure. Subjects were followed for five years. Principalization was discovered to be the most successful and projection the least successful defense. (JAC)

  18. Macrophage defense mechanisms against intracellular bacteria.

    PubMed

    Weiss, Günter; Schaible, Ulrich E

    2015-03-01

    Macrophages and neutrophils play a decisive role in host responses to intracellular bacteria including the agent of tuberculosis (TB), Mycobacterium tuberculosis as they represent the forefront of innate immune defense against bacterial invaders. At the same time, these phagocytes are also primary targets of intracellular bacteria to be abused as host cells. Their efficacy to contain and eliminate intracellular M. tuberculosis decides whether a patient initially becomes infected or not. However, when the infection becomes chronic or even latent (as in the case of TB) despite development of specific immune activation, phagocytes have also important effector functions. Macrophages have evolved a myriad of defense strategies to combat infection with intracellular bacteria such as M. tuberculosis. These include induction of toxic anti-microbial effectors such as nitric oxide and reactive oxygen intermediates, the stimulation of microbe intoxication mechanisms via acidification or metal accumulation in the phagolysosome, the restriction of the microbe's access to essential nutrients such as iron, fatty acids, or amino acids, the production of anti-microbial peptides and cytokines, along with induction of autophagy and efferocytosis to eliminate the pathogen. On the other hand, M. tuberculosis, as a prime example of a well-adapted facultative intracellular bacterium, has learned during evolution to counter-balance the host's immune defense strategies to secure survival or multiplication within this otherwise hostile environment. This review provides an overview of innate immune defense of macrophages directed against intracellular bacteria with a focus on M. tuberculosis. Gaining more insights and knowledge into this complex network of host-pathogen interaction will identify novel target sites of intervention to successfully clear infection at a time of rapidly emerging multi-resistance of M. tuberculosis against conventional antibiotics.

  19. Defense mechanisms: 40 years of empirical research.

    PubMed

    Cramer, Phebe

    2015-01-01

    This article reviews research on defense mechanisms carried out over the past 40 years with children, adolescents, adults, and psychiatric patients. Both experimental and observational studies are included.

  20. Defense Mechanisms Associated with Borderline Personality Disorder

    PubMed Central

    Zanarini, Mary C.; Weingeroff, Jolie L.; Frankenburg, Frances R.

    2011-01-01

    This study assessed the defensive functioning of 290 criteria-defined borderline patients and compared it to that of 72 patients with other forms of axis II psychopathology. The Defense Style Questionnaire, a self-report measure with demonstrated criterion validity and internal consistency, was administered to 362 axis II inpatients diagnosed using semistructured interviews of proven reliability. Borderline patients had significantly higher scores than axis II comparison subjects on three of the four defense styles assessed by the DSQ: self-sacrificing, maladaptive action, and image-distorting defenses. They also had significantly higher scores than axis II comparison subjects on eight of the 19 defense mechanisms studied. More specifically, borderline patients had significantly higher scores on one neurotic-level defense (undoing), four immature defenses (acting out, emotional hypochondriasis, passive aggression, and projection), and two image- distorting/borderline defenses (projective identification and splitting). In contrast, axis II comparison subjects had a significantly higher score than borderline patients on one mature defense (suppression). When all significant defenses were considered together, three were found to be significant predictors of a borderline diagnosis: acting out, emotional hypochondriasis, and undoing. This model has both good sensitivity (.95) and positive predictive power (.86). Taken together, the results of this study suggest that the defensive profile of borderline patients is distinct from that of patients with other forms of axis II pathology. They also suggest that the defensive triad of acting out, emotional hypochondriasis, and undoing may serve as a useful clinical marker for the borderline diagnosis, particularly in settings where the base rate of the disorder is high. PMID:19379090

  1. Mechanisms of plant defense against insect herbivores

    PubMed Central

    War, Abdul Rashid; Paulraj, Michael Gabriel; Ahmad, Tariq; Buhroo, Abdul Ahad; Hussain, Barkat; Ignacimuthu, Savarimuthu; Sharma, Hari Chand

    2012-01-01

    Plants respond to herbivory through various morphological, biochemicals, and molecular mechanisms to counter/offset the effects of herbivore attack. The biochemical mechanisms of defense against the herbivores are wide-ranging, highly dynamic, and are mediated both by direct and indirect defenses. The defensive compounds are either produced constitutively or in response to plant damage, and affect feeding, growth, and survival of herbivores. In addition, plants also release volatile organic compounds that attract the natural enemies of the herbivores. These strategies either act independently or in conjunction with each other. However, our understanding of these defensive mechanisms is still limited. Induced resistance could be exploited as an important tool for the pest management to minimize the amounts of insecticides used for pest control. Host plant resistance to insects, particularly, induced resistance, can also be manipulated with the use of chemical elicitors of secondary metabolites, which confer resistance to insects. By understanding the mechanisms of induced resistance, we can predict the herbivores that are likely to be affected by induced responses. The elicitors of induced responses can be sprayed on crop plants to build up the natural defense system against damage caused by herbivores. The induced responses can also be engineered genetically, so that the defensive compounds are constitutively produced in plants against are challenged by the herbivory. Induced resistance can be exploited for developing crop cultivars, which readily produce the inducible response upon mild infestation, and can act as one of components of integrated pest management for sustainable crop production. PMID:22895106

  2. Defense Mechanism Card Pull in TAT Stories.

    PubMed

    Cramer, Phebe

    2017-01-01

    This study investigates the question of whether different Thematic Apperception Test (TAT; Murray, 1943 ) cards are likely to prompt stories that are characterized by different defense mechanisms. This condition is known as card pull and refers to the probability that different TAT cards elicit different personality scores for the same variable. If so, the assessment of defense use would be importantly influenced by the TAT cards used in an assessment. TAT stories from 3 different community samples were examined (Ns = 91, 98, 121), using a statistical method developed by Stein et al ( 2014 ). The results indicated that different TAT cards pull for different defenses, as assessed by the Defense Mechanism Manual (DMM: Cramer, 1991b ). However, the nature of card pull was not always consistent across samples. These dissimilarities could be due to group differences, or to the presence of different TAT cards used in the test battery, indicating that card pull is importantly determined by context.

  3. Defense mechanisms and psychological adjustment in childhood.

    PubMed

    Sandstrom, Marlene J; Cramer, Phebe

    2003-08-01

    The association between maturity of defense use and psychological functioning was assessed in a group of 95 elementary school children. Defense mechanisms were measured using a valid and reliable storytelling task, and psychological adjustment was assessed through a combination of parent and self-report questionnaires. Correlational analyses indicated that children who relied on the developmentally immature defense of denial reported higher levels of self-rated social anxiety and depression and received higher ratings of parent-reported internalizing and externalizing behavior problems. However, children who made use of the developmentally mature defense of identification exhibited higher scores on perceived competence in social, academic, conduct, athletic, and global domains. Significantly, there was no relationship between children's use of denial and their level of perceived competence or between children's use of identification and their degree of maladjustment.

  4. Antiviral Defense Mechanisms in Honey Bees

    PubMed Central

    Brutscher, Laura M.; Daughenbaugh, Katie F.; Flenniken, Michelle L.

    2015-01-01

    Honey bees are significant pollinators of agricultural crops and other important plant species. High annual losses of honey bee colonies in North America and in some parts of Europe have profound ecological and economic implications. Colony losses have been attributed to multiple factors including RNA viruses, thus understanding bee antiviral defense mechanisms may result in the development of strategies that mitigate colony losses. Honey bee antiviral defense mechanisms include RNA-interference, pathogen-associated molecular pattern (PAMP) triggered signal transduction cascades, and reactive oxygen species generation. However, the relative importance of these and other pathways is largely uncharacterized. Herein we review the current understanding of honey bee antiviral defense mechanisms and suggest important avenues for future investigation. PMID:26273564

  5. Defense Mechanisms of Conifers 1

    PubMed Central

    Lewinsohn, Efraim; Gijzen, Mark; Croteau, Rodney

    1991-01-01

    Levels of monoterpene cyclase activity were determined in extracts from wounded and unwounded saplings of 10 conifer species to assess whether oleoresin biosynthesis is induced by stem wounding. Species of Abies and Picea, with low to moderate levels of constitutive monoterpene cyclase activity, exhibited a five- to 15-fold increase in cyclase activity 7 days after wounding relative to unwounded controls. In contrast, species of genera such as Pinus, with high levels of constitutive cyclase activity, did not significantly respond to wounding by alteration in the level of cyclase activity. The highest fold increase in monoterpene cyclase activity was consistently observed in Abies grandis, and the time-course of induction of activity following stem wounding in this species demonstrated a threefold increase at 2 days relative to unwounded controls, rising to a maximum increase in the response at 9 days (greater than 10-fold) followed by an apparent decline. The wound response was localized, and both bark (phloem) and wood (xylem) tissues displayed increased cyclase activity at the wound site. The magnitude of the increase in cyclase activity was dependent on the severity of the wound. PMID:16668184

  6. Defense Mechanisms of Conifers 1

    PubMed Central

    Lewinsohn, Efraim; Gijzen, Mark; Savage, Thomas J.; Croteau, Rodney

    1991-01-01

    Cell-free extracts from Pinus ponderosa Lawson (ponderosa pine) and Pinus sylvestris L. (Scotch pine) wood exhibited high levels of monoterpene synthase (cyclase) activity, whereas bark extracts of these species contained no detectable activity, and they inhibited cyclase activity when added to extracts from wood, unless polyvinylpyrrolidone was included in the preparation. The molecular mass of the polyvinylpyrrolidone added was of little consequence; however, polyvinylpolypyrrolidone (a cross-linked insoluble form of the polymer) was ineffective in protecting enzyme activity. Based on these observations, methods were developed for the efficient extraction and assay of monoterpene cyclase activity from conifer stem (wood and bark) tissue. The level of monoterpene cyclase activity for a given conifer species was shown to correlate closely with the monoterpene content of the oleoresin and with the degree of anatomical complexity of the specialized resin-secreting structures. Cyclase activity and monoterpene content were lowest in the stems of species containing only isolated resin cells, such as western red cedar (Thuja plicata D. Don). Increasing levels of cyclase activity and oleoresin monoterpenes were observed in advancing from species with multicellular resin blisters (true firs [Abies]) to those with organized resin passages, such as western larch (Larix occidentalis Nutt.), Colorado blue spruce (Picea pungens Engelm.) and Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco). The highest levels of cyclase activity and oleoresin monoterpenes were noted in Pinus species that contain the most highly developed resin duct systems. The relationship between biosynthetic capacity, as measured by cyclase activity, monoterpene content, and the degree of organization of the secretory structures for a given species, may reflect the total number of specialized resin-producing cells per unit mass of stem tissue. PMID:16668182

  7. Pythium infection activates conserved plant defense responses in mosses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The moss Physcomitrella patens (P. patens) is a useful model to study abiotic stress responses since it is highly tolerant to drought, salt and osmotic stress. However, little is known about the defense mechanisms activated in this moss after pathogen assault. Here the induction of defense responses...

  8. Adaptation Mechanisms in the Evolution of Moss Defenses to Microbes

    PubMed Central

    Ponce de León, Inés; Montesano, Marcos

    2017-01-01

    Bryophytes, including mosses, liverworts and hornworts are early land plants that have evolved key adaptation mechanisms to cope with abiotic stresses and microorganisms. Microbial symbioses facilitated plant colonization of land by enhancing nutrient uptake leading to improved plant growth and fitness. In addition, early land plants acquired novel defense mechanisms to protect plant tissues from pre-existing microbial pathogens. Due to its evolutionary stage linking unicellular green algae to vascular plants, the non-vascular moss Physcomitrella patens is an interesting organism to explore the adaptation mechanisms developed in the evolution of plant defenses to microbes. Cellular and biochemical approaches, gene expression profiles, and functional analysis of genes by targeted gene disruption have revealed that several defense mechanisms against microbial pathogens are conserved between mosses and flowering plants. P. patens perceives pathogen associated molecular patterns by plasma membrane receptor(s) and transduces the signal through a MAP kinase (MAPK) cascade leading to the activation of cell wall associated defenses and expression of genes that encode proteins with different roles in plant resistance. After pathogen assault, P. patens also activates the production of ROS, induces a HR-like reaction and increases levels of some hormones. Furthermore, alternative metabolic pathways are present in P. patens leading to the production of a distinct metabolic scenario than flowering plants that could contribute to defense. P. patens has acquired genes by horizontal transfer from prokaryotes and fungi, and some of them could represent adaptive benefits for resistance to biotic stress. In this review, the current knowledge related to the evolution of plant defense responses against pathogens will be discussed, focusing on the latest advances made in the model plant P. patens. PMID:28360923

  9. Adaptation Mechanisms in the Evolution of Moss Defenses to Microbes.

    PubMed

    Ponce de León, Inés; Montesano, Marcos

    2017-01-01

    Bryophytes, including mosses, liverworts and hornworts are early land plants that have evolved key adaptation mechanisms to cope with abiotic stresses and microorganisms. Microbial symbioses facilitated plant colonization of land by enhancing nutrient uptake leading to improved plant growth and fitness. In addition, early land plants acquired novel defense mechanisms to protect plant tissues from pre-existing microbial pathogens. Due to its evolutionary stage linking unicellular green algae to vascular plants, the non-vascular moss Physcomitrella patens is an interesting organism to explore the adaptation mechanisms developed in the evolution of plant defenses to microbes. Cellular and biochemical approaches, gene expression profiles, and functional analysis of genes by targeted gene disruption have revealed that several defense mechanisms against microbial pathogens are conserved between mosses and flowering plants. P. patens perceives pathogen associated molecular patterns by plasma membrane receptor(s) and transduces the signal through a MAP kinase (MAPK) cascade leading to the activation of cell wall associated defenses and expression of genes that encode proteins with different roles in plant resistance. After pathogen assault, P. patens also activates the production of ROS, induces a HR-like reaction and increases levels of some hormones. Furthermore, alternative metabolic pathways are present in P. patens leading to the production of a distinct metabolic scenario than flowering plants that could contribute to defense. P. patens has acquired genes by horizontal transfer from prokaryotes and fungi, and some of them could represent adaptive benefits for resistance to biotic stress. In this review, the current knowledge related to the evolution of plant defense responses against pathogens will be discussed, focusing on the latest advances made in the model plant P. patens.

  10. Mechanisms of Defense: Nepenthe Theory and Psychiatric Symptomatology

    ERIC Educational Resources Information Center

    Azibo, Daudi Ajani ya

    2007-01-01

    Results of exploratory research on defense mechanisms and psychiatric symptomatology are reported about Black students enrolled in classes on the campus of one Historically Black College and University. Theoretical influences are twofold: ego mechanisms of defense conceptualized hierarchically and a culture-specific view of defense mechanism…

  11. Department of Defense Offshore Military Activities Program

    DTIC Science & Technology

    1987-03-16

    joint use of offshore areas for military and mineral exploration or developmental purposes. (See enclosure 2.) In carrying out negotiations with elements...that from time to time and from place to place the requirements for mineral exploration /development and defense related activities may conflict. In...area, certain defense- related activities on the OCS may be irreconcilable with mineral exploration / development and will, under the procedures

  12. Botryticides affect grapevine leaf photosynthesis without inducing defense mechanisms.

    PubMed

    Petit, Anne-Noëlle; Wojnarowiez, Geneviève; Panon, Marie-Laure; Baillieul, Fabienne; Clément, Christophe; Fontaine, Florence; Vaillant-Gaveau, Nathalie

    2009-02-01

    The effects of the two botryticides, fludioxonil (fdx) and fenhexamid (fhd), were investigated on grapevine leaves (Vitis vinifera L. cv. Pinot noir) following photosynthesis and defense mechanisms. Treatments were carried out in vineyard at the end of flowering. Phytotoxicity of both fungicides was evaluated by measuring variations of leaf photosynthetic parameters and correlated expression of photosynthesis-related genes. Results demonstrated that similar decrease in photosynthesis was caused by fdx and fhd applications. Moreover, the mechanism leading to photosynthesis alteration seems to be the same for both fungicides. Stomatal limitation to photosynthetic gas exchange did not change following treatments indicating that inhibition of photosynthesis was mostly attributed to non-stomatal factors. Nevertheless, fungicides-induced depression of photosynthesis was related neither to a decrease in Rubisco carboxylation efficiency and in the capacity for regeneration of ribulose 1,5-bisphosphate nor to loss in PSII activity. However, fdx and fhd treatments generated repression of genes encoding proteins involved in the photosynthetic process. Indeed, decreased photosynthesis was coupled with repression of PsbP subunit of photosystem II (psbP1), chlorophyll a/b binding protein of photosystem I (cab) and Rubisco small subunit (rbcS) genes. A repression of these genes may participate in the photosynthesis alteration. To our knowledge, this is the first study of photosynthesis-related gene expression following fungicide stress. In the meantime, defense responses were followed by measuring chitinase activity and expression of varied defense-related genes encoding proteins involved in phenylpropanoid synthesis (PAL) or octadecanoid synthesis (LOX), as well as pathogenesis-related protein (Chi4C). No induction of defense was observed in botryticides-treated leaves. To conclude, the photosynthesis is affected without any triggering of plant defense responses.

  13. Defense mechanisms of the respiratory system and aerosol production systems.

    PubMed

    Zarogoulidis, Paul; Darwiche, Kaid; Yarmus, Lonny; Spyratos, Dionysios; Secen, Nevena; Hohenforst-Schmidt, Wolfgang; Katsikogiannis, Nikolaos; Huang, Haidong; Gschwendtner, Andreas; Zarogoulidis, Konstantinos

    2014-03-01

    Aerosolized therapies have been used in everyday clinical practice for decades. Experimentation with different delivery systems have led to the creation of aerosolized insulin, antibiotics, gene therapy and chemotherapy. Several of these therapies are already clinically available while others are being investigated in active clinical trials. The main factors affecting the efficiency and safety of the aerosolized therapies are the production of the aerosol, distribution/deposition of the aerosol throughout the lung parenchyma, respiratory defense mechanisms and tissue/pharmaceutical molecule interactions. Current methods of aerosol production and distribution will be presented along with an overview of the respiratory defense mechanisms. In addition, methods of aerosol evaluation in conjunction with a future perspective of the potential development of aerosol therapies will be presented.

  14. Defense mechanisms in adolescent conduct disorder and adjustment reaction.

    PubMed

    Cramer, Phebe; Kelly, Francis D

    2004-02-01

    The use of defense mechanisms by male and female adolescents with a diagnosis of conduct disorder was compared with the defense use of adolescents with a diagnosis of adjustment reaction. Because conduct disorder has been shown to be associated with a developmental lag in several areas of psychological functioning, we expected that these adolescents would show immaturity in the use of defenses. This expectation was confirmed. As compared with adjustment reaction, conduct disordered youths were more likely to use the immature defense of denial and less likely to use the mature defense of identification.

  15. The Sweet Potato NAC-Domain Transcription Factor IbNAC1 Is Dynamically Coordinated by the Activator IbbHLH3 and the Repressor IbbHLH4 to Reprogram the Defense Mechanism against Wounding

    PubMed Central

    Chen, Shi-Peng; Kuo, Chih-Hsien; Lu, Hsueh-Han; Lo, Hui-Shan; Yeh, Kai-Wun

    2016-01-01

    IbNAC1 is known to activate the defense system by reprogramming a genetic network against herbivory in sweet potato. This regulatory activity elevates plant defense potential but relatively weakens plants by IbNAC1-mediated JA response. The mechanism controlling IbNAC1 expression to balance plant vitality and survival remains unclear. In this study, a wound-responsive G-box cis-element in the IbNAC1 promoter from -1484 to -1479 bp was identified. From a screen of wound-activated transcriptomic data, one transcriptional activator, IbbHLH3, and one repressor, IbbHLH4, were selected that bind to and activate or repress, respectively, the G-box motif in the IbNAC1 promoter to modulate the IbNAC1-mediated response. In the early wound response, the IbbHLH3-IbbHLH3 protein complex binds to the G-box motif to activate IbNAC1 expression. Thus, an elegant defense network is activated against wounding stress. Until the late stages of wounding, IbbHLH4 interacts with IbbHLH3, and the IbbHLH3-IbbHLH4 heterodimer competes with the IbbHLH3-IbbHLH3 complex to bind the G-box and suppress IbNAC1 expression and timely terminates the defense network. Moreover, the JAZs and IbEIL1 proteins interact with IbbHLH3 to repress the transactivation function of IbbHLH3 in non-wounded condition, but their transcription is immediately inhibited upon early wounding. Our work provides a genetic model that accurately switches the regulatory mechanism of IbNAC1 expression to adjust wounding physiology and represents a delicate defense regulatory network in plants. PMID:27780204

  16. Adversity Quotient and Defense Mechanism of Secondary School Students

    ERIC Educational Resources Information Center

    Nikam, Vibhawari B.; Uplane, Megha M.

    2013-01-01

    The present study was conducted to explore the relationship between Adversity Quotient (AQ) and Defense Mechanism (DM) of secondary school students. The aim of the study was to ascertain relationship between Adversity Quotient and Defense mechanism i. e. Turning against object (TAO), Projection (PRO), Turning against self (TAS), Principalisation…

  17. Plant defense activators: applications and prospects in cereal crops

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This review addresses the current understanding of the plant immune response and the molecular mechanisms responsible for systemic acquired resistance as well as the phenomenon of "priming" in plant defense. A detailed discussion of the role of salicylic acid in activating the plant transcription c...

  18. Denial Defense Mechanism in Dialyzed Patients

    PubMed Central

    Nowak, Zbigniew; Wańkowicz, Zofia; Laudanski, Krzysztof

    2015-01-01

    Background It is a struggle to identify the most adaptive coping strategies with disease-mediated stress. Here, we hypothesize that intensity of coping strategies, including denial, in patients with end-stage renal disease (ESRD), varies with type of renal replacement therapy (RRT). Material/Methods We enrolled 60 in-center hemodialyzed patients (HD) and 55 patients treated with continuous ambulatory peritoneal dialysis (CAPD). We administered the Coping Inventory with Stressful Situation, Profile of Mood States, and Stroop Anxiety Inventory to measure patient coping strategies in the context of their ESRD. Denial defense mechanism was measured via the IBS-R/ED. The Nottingham Health Profile was used to evaluate self-perceived quality of life. Serum potassium, urea, creatinine, phosphorus, calcium, albumin, and hematocrit were utilized as the measurements of adequacy of dialysis. Results HD patients had higher self-reported intensity of denial mechanism and avoidance-oriented strategies versus CAPD patients. Because a single strategy is almost never employed, we conducted cluster analysis. We identify 3 patterns of coping strategies using cluster analysis. “Repressors” employed denial and avoidance strategies and were predominant in HD. The second cluster consists of subjects employing predominantly task-oriented strategies with equal distribution among dialyzed patients. The third cluster encompassed a small group of patients who shared higher intensity of both denial and task-oriented strategies. Health-related outcome, anxiety, and mood profile were similar across all patients. Conclusions HD patients predominantly used “repressive” strategies. Patients on RRT utilized denial and avoidance-based strategies to achieve satisfactory outcome in terms of perceived quality of life. We conclude that these coping mechanisms that were previously thought to be inferior are beneficial to patient compliance with RRT. PMID:26094792

  19. Defense Mechanisms in "Pure" Anxiety and "Pure" Depressive Disorders.

    PubMed

    Colovic, Olga; Lecic Tosevski, Dusica; Perunicic Mladenovic, Ivana; Milosavljevic, Maja; Munjiza, Ana

    2016-10-01

    Our study was intended to test whether there are any differences in the way defense mechanisms are used by patients suffering from pure anxiety and those with pure depressive disorders. The sample size was as follows: depressive disorders without psychotic symptoms 30, anxiety disorders 30, and the healthy control group 30. The assessment of defense mechanisms was made using the DSQ-40 questionnaire. Our findings show that "pure" anxiety disorders differ from "pure" depressive disorders only in the use of immature defense mechanisms. The group with depressive disorders was significantly more prone to use immature defense mechanisms than the group with anxiety disorders (p = 0.005), primarily projection (p = 0.001) and devaluation (p = 0.003). These defense mechanisms may therefore be used both to differentiate between anxiety and depressive disorders and also to determine which symptoms (anxiety or depressive disorders) are dominant at any given stage of treatment.

  20. The dimensionality of defense-mechanism parcels in the Defense Style Questionnaire-40.

    PubMed

    Wilkinson, Wayne W; Ritchie, Timothy D

    2015-03-01

    The Defense Style Questionnaire-40 (DSQ-40; Andrews, Singh, & Bond, 1993) uses pairs of items to measure 20 individual defense mechanisms. In a statistical sense, these item pairs represent parcels and are subject to the standards of unidimensionality demanded of parcels in general. Using a 2-facet modeling approach (N = 672), the present study examined the dimensionality of the defense-mechanism parcels in the DSQ-40 and found that the majority of the parcels did not satisfy the criteria for unidimensionality. In addition, the original 3-factor model of defense styles was not tenable with the present data. Overall, the results suggest caution when attempting to assess individual defense mechanisms using the DSQ-40.

  1. In Defense of Active Learning

    ERIC Educational Resources Information Center

    Pica, Rae

    2008-01-01

    Effective early childhood teachers use what they know about and have observed in young children to design programs to meet children's developmental needs. Play and active learning are key tools to address those needs and facilitate children's early education. In this article, the author discusses the benefits of active learning in the education of…

  2. Defense mechanisms in schizotypal, borderline, antisocial, and narcissistic personality disorders.

    PubMed

    Perry, J Christopher; Presniak, Michelle D; Olson, Trevor R

    2013-01-01

    Numerous authors have theorized that defense mechanisms play a role in personality disorders. We reviewed theoretical writings and empirical studies about defenses in schizotypal, borderline, antisocial, and narcissistic personality disorders, developing hypotheses about these differential relationships. We then examined these hypotheses using dynamic interview data rated for defenses in a study of participants (n = 107) diagnosed with these four personality disorder types. Overall, the prevalence of immature defenses was substantial, and all four disorders fit within the broad borderline personality organization construct. Defenses predicted the most variance in borderline and the least variance in schizotypal personality disorder, suggesting that dynamic factors played the largest role in borderline and the least in schizotypal personality. Central to borderline personality were strong associations with major image-distorting defenses, primarily splitting of self and other's images, and the hysterical level defenses, dissociation and repression. Narcissistic and antisocial personality disorders shared minor image-distorting defenses, such as omnipotence or devaluation, while narcissistic also used splitting of self-images and antisocial used disavowal defenses like denial. Overall, differential relationships between specific defenses and personality disorder types were largely consistent with the literature, and consistent with the importance that the treatment literature ascribes to working with defenses.

  3. Do toxic heavy metals affect antioxidant defense mechanisms in humans?

    PubMed

    Wieloch, Monika; Kamiński, Piotr; Ossowska, Anna; Koim-Puchowska, Beata; Stuczyński, Tomasz; Kuligowska-Prusińska, Magdalena; Dymek, Grażyna; Mańkowska, Aneta; Odrowąż-Sypniewska, Grażyna

    2012-04-01

    The aim of this study was to prove whether anthropogenic pollution affects antioxidant defense mechanisms such as superoxide dismutase (SOD) and catalase (CAT) activity, ferritin (FRT) concentration and total antioxidant status (TAS) in human serum. The study area involves polluted and salted environment (Kujawy region; northern-middle Poland) and Tuchola Forestry (unpolluted control area). We investigated 79 blood samples of volunteers from polluted area and 82 from the control in 2008 and 2009. Lead, cadmium and iron concentrations were measured in whole blood by the ICP-MS method. SOD and CAT activities were measured in serum using SOD and CAT Assay Kits by the standardized colorimetric method. Serum TAS was measured spectrophotometrically by the modified Benzie and Strain (1996) method and FRT concentration-by the immunonefelometric method. Pb and Cd levels and SOD activity were higher in volunteers from polluted area as compared with those from the control (0.0236 mg l(-1) vs. 0.014 mg l(-1); 0.0008 mg l(-1) vs. 0.0005 mg l(-1); 0.137 Um l(-1) vs. 0.055 Um l(-1), respectively). Fe level, CAT activity and TAS were lower in serum of volunteers from polluted area (0.442 g l(-1) vs. 0.476 gl(-1); 3.336 nmol min(-1)ml(-1) vs. 6.017 nmol min(-1)ml(-1); 0.731 Trolox-equivalents vs. 0.936 Trolox-equivalents, respectively), whilst differences in FRT concentration were not significant (66.109 μg l(-1) vs. 37.667 μg l(-1), p=0.3972). Positive correlations between Pb (r=0.206), Cd (r=0.602) and SOD in the inhabitants of polluted area, and between Cd and SOD in the control (r=0.639) were shown. In volunteers from both studied environments TAS-FRT (polluted: r=0.625 vs. control: r=0.837) and Fe-FRT (polluted area: r=0.831 vs. control: r=0.407) correlations, and Pb-FRT (r=0.360) and Pb-TAS (r=0.283) in the control were stated. The higher lead and cadmium concentrations in blood cause an increase of SOD activity. It suggests that this is one of the defense mechanisms of an

  4. Mechanisms and strategies of plant defense against Botrytis cinerea.

    PubMed

    AbuQamar, Synan; Moustafa, Khaled; Tran, Lam Son

    2017-03-01

    Biotic factors affect plant immune responses and plant resistance to pathogen infections. Despite the considerable progress made over the past two decades in manipulating genes, proteins and their levels from diverse sources, no complete genetic tolerance to environmental stresses has been developed so far in any crops. Plant defense response to pathogens, including Botrytis cinerea, is a complex biological process involving various changes at the biochemical, molecular (i.e. transcriptional) and physiological levels. Once a pathogen is detected, effective plant resistance activates signaling networks through the generation of small signaling molecules and the balance of hormonal signaling pathways to initiate defense mechanisms to the particular pathogen. Recently, studies using Arabidopsis thaliana and crop plants have shown that many genes are involved in plant responses to B. cinerea infection. In this article, we will review our current understanding of mechanisms regulating plant responses to B. cinerea with a particular interest on hormonal regulatory networks involving phytohormones salicylic acid (SA), jasmonic acid (JA), ethylene (ET) and abscisic acid (ABA). We will also highlight some potential gene targets that are promising for improving crop resistance to B. cinerea through genetic engineering and breeding programs. Finally, the role of biological control as a complementary and alternative disease management will be overviewed.

  5. Heavy Metal Stress and Some Mechanisms of Plant Defense Response

    PubMed Central

    Emamverdian, Abolghassem; Ding, Yulong; Mokhberdoran, Farzad; Xie, Yinfeng

    2015-01-01

    Unprecedented bioaccumulation and biomagnification of heavy metals (HMs) in the environment have become a dilemma for all living organisms including plants. HMs at toxic levels have the capability to interact with several vital cellular biomolecules such as nuclear proteins and DNA, leading to excessive augmentation of reactive oxygen species (ROS). This would inflict serious morphological, metabolic, and physiological anomalies in plants ranging from chlorosis of shoot to lipid peroxidation and protein degradation. In response, plants are equipped with a repertoire of mechanisms to counteract heavy metal (HM) toxicity. The key elements of these are chelating metals by forming phytochelatins (PCs) or metallothioneins (MTs) metal complex at the intra- and intercellular level, which is followed by the removal of HM ions from sensitive sites or vacuolar sequestration of ligand-metal complex. Nonenzymatically synthesized compounds such as proline (Pro) are able to strengthen metal-detoxification capacity of intracellular antioxidant enzymes. Another important additive component of plant defense system is symbiotic association with arbuscular mycorrhizal (AM) fungi. AM can effectively immobilize HMs and reduce their uptake by host plants via binding metal ions to hyphal cell wall and excreting several extracellular biomolecules. Additionally, AM fungi can enhance activities of antioxidant defense machinery of plants. PMID:25688377

  6. Heavy metal stress and some mechanisms of plant defense response.

    PubMed

    Emamverdian, Abolghassem; Ding, Yulong; Mokhberdoran, Farzad; Xie, Yinfeng

    2015-01-01

    Unprecedented bioaccumulation and biomagnification of heavy metals (HMs) in the environment have become a dilemma for all living organisms including plants. HMs at toxic levels have the capability to interact with several vital cellular biomolecules such as nuclear proteins and DNA, leading to excessive augmentation of reactive oxygen species (ROS). This would inflict serious morphological, metabolic, and physiological anomalies in plants ranging from chlorosis of shoot to lipid peroxidation and protein degradation. In response, plants are equipped with a repertoire of mechanisms to counteract heavy metal (HM) toxicity. The key elements of these are chelating metals by forming phytochelatins (PCs) or metallothioneins (MTs) metal complex at the intra- and intercellular level, which is followed by the removal of HM ions from sensitive sites or vacuolar sequestration of ligand-metal complex. Nonenzymatically synthesized compounds such as proline (Pro) are able to strengthen metal-detoxification capacity of intracellular antioxidant enzymes. Another important additive component of plant defense system is symbiotic association with arbuscular mycorrhizal (AM) fungi. AM can effectively immobilize HMs and reduce their uptake by host plants via binding metal ions to hyphal cell wall and excreting several extracellular biomolecules. Additionally, AM fungi can enhance activities of antioxidant defense machinery of plants.

  7. A recessive resistance to rice yellow mottle virus is associated with a rice homolog of the CPR5 gene, a regulator of active defense mechanisms.

    PubMed

    Orjuela, Julie; Deless, E F Thiémélé; Kolade, Olufisayo; Chéron, Sophie; Ghesquière, Alain; Albar, Laurence

    2013-12-01

    RYMV2 is a major recessive resistance gene identified in cultivated African rice (Oryza glaberrima) which confers high resistance to the Rice yellow mottle virus (RYMV). We mapped RYMV2 in an approximately 30-kb interval in which four genes have been annotated. Sequencing of the candidate region in the resistant Tog7291 accession revealed a single mutation affecting a predicted gene, as compared with the RYMV-susceptible O. glaberrima CG14 reference sequence. This mutation was found to be a one-base deletion leading to a truncated and probably nonfunctional protein. It affected a gene homologous to the Arabidopsis thaliana CPR5 gene, known to be a defense mechanism regulator. Only seven O. glaberrima accessions showing this deletion were identified in a collection consisting of 417 accessions from three rice species. All seven accessions were resistant to RYMV, which is an additional argument in favor of the involvement of the deletion in resistance. In addition, fine mapping of a resistance quantitative trait locus in O. sativa advanced backcrossed lines pinpointed a 151-kb interval containing RYMV2, suggesting that allelic variants of the same gene may control both high and partial resistance.

  8. Physcomitrella patens Activates Defense Responses against the Pathogen Colletotrichum gloeosporioides

    PubMed Central

    Reboledo, Guillermo; del Campo, Raquel; Alvarez, Alfonso; Montesano, Marcos; Mara, Héctor; Ponce de León, Inés

    2015-01-01

    The moss Physcomitrella patens is a suitable model plant to analyze the activation of defense mechanisms after pathogen assault. In this study, we show that Colletotrichum gloeosporioides isolated from symptomatic citrus fruit infects P. patens and cause disease symptoms evidenced by browning and maceration of tissues. After C. gloeosporioides infection, P. patens reinforces the cell wall by the incorporation of phenolic compounds and induces the expression of a Dirigent-protein-like encoding gene that could lead to the formation of lignin-like polymers. C. gloeosporioides-inoculated protonemal cells show cytoplasmic collapse, browning of chloroplasts and modifications of the cell wall. Chloroplasts relocate in cells of infected tissues toward the initially infected C. gloeosporioides cells. P. patens also induces the expression of the defense genes PAL and CHS after fungal colonization. P. patens reporter lines harboring the auxin-inducible promoter from soybean (GmGH3) fused to β-glucuronidase revealed an auxin response in protonemal tissues, cauloids and leaves of C. gloeosporioides-infected moss tissues, indicating the activation of auxin signaling. Thus, P. patens is an interesting plant to gain insight into defense mechanisms that have evolved in primitive land plants to cope with microbial pathogens. PMID:26389888

  9. Defense Mechanisms, Psychosomatic Symptomatology, and Conjugate Lateral Eye Movements

    ERIC Educational Resources Information Center

    Gur, Raquel E.; Gur, Ruben C.

    1975-01-01

    Subjects were classified into left movers, right movers, and bidirectionals according to the characteristic direction of their eye movements in response to questions. The three groups were compared on their preferential use of defense mechanisms and on the number of psychosomatic complaints. (Author)

  10. Grooming Behavior as a Mechanism of Insect Disease Defense

    PubMed Central

    Zhukovskaya, Marianna; Yanagawa, Aya; Forschler, Brian T.

    2013-01-01

    Grooming is a well-recognized, multipurpose, behavior in arthropods and vertebrates. In this paper, we review the literature to highlight the physical function, neurophysiological mechanisms, and role that grooming plays in insect defense against pathogenic infection. The intricate relationships between the physical, neurological and immunological mechanisms of grooming are discussed to illustrate the importance of this behavior when examining the ecology of insect-pathogen interactions. PMID:26462526

  11. Induced defense mechanisms in an aquatic angiosperm to insect herbivory.

    PubMed

    Fornoff, Felix; Gross, Elisabeth M

    2014-05-01

    In terrestrial angiosperms, defense and resistance mechanisms against herbivores have been studied extensively; yet this topic is poorly understood in aquatic angiosperms. We investigated induced response mechanisms in Myriophyllum spicatum to the generalist insect herbivore Acentria ephemerella in three independent experiments. Various morphological and chemical response variables were examined in grazed apical shoots and compared to undamaged controls. We further estimated plant palatability of induced and non-induced apices in choice assays, and assessed the growth response of Acentria larvae in no-choice feeding assays. Leaves of induced apices were splayed out horizontally and changed in color from green to red. The dry matter content and thus plant toughness increased by up to 19%, but silica levels stayed constant. Induced apices exhibited a decline in chlorophyll content of up to 34%, reflected also by a 10% decrease in nitrogen levels, while nitrogen increased by 14% in lower parts of grazed shoots. Also, herbivore-deterring total phenolic compounds increased by up to 20% in apices. In choice trials, Acentria larvae strongly avoided grazed tips, and growth was reduced by 25% on induced apices. In total, we observed five different induced resistance and defensive traits in grazed apices: changes in appearance, increased plant toughness, delocalization of N-containing metabolites, increased polyphenols, and reduced nutritional value. The observed changes prevent herbivore damage and loss of apical tissue, which are most valuable for plant fitness. Our study presents the first evidence of multiple, parallel defense strategies including constitutive and induced defense mechanisms in a freshwater angiosperm.

  12. Control of Lung Defense by Mucins and Macrophages: Ancient defense mechanisms with modern functions

    PubMed Central

    Janssen, William J.; Stefanski, Adrianne L.; Bochner, Bruce S.; Evans, Christopher M.

    2016-01-01

    Due to the need to balance the requirement for efficient respiration in the face of tremendous levels of exposure to endogenous and environmental challenges, it is crucial for the lungs to maintain sustainable defense that minimizes damage caused by exposures and the detrimental effects of inflammation to delicate gas exchange surfaces. Accordingly, epithelial and macrophage defenses constitute essential 1st and 2nd lines of protection that prevent the accumulation of potentially harmful agents in the lungs, and under homeostatic conditions do so effectively without inducing inflammation. Though seemingly distinct, recent data show that epithelial and macrophage mediated defenses are linked through their shared reliance on airway mucins, in particular the polymeric mucin MUC5B. This review highlights our understanding of novel mechanisms that link mucus and macrophage defenses. The roles of phagocytosis and the effects of factors that are contained within mucus on phagocytosis, as well as newly identified roles for mucin glycoproteins in the direct regulation of leukocyte functions are discussed. The emergence of this nascent field of glycoimmunobiology sets forth a new paradigm for considering how homeostasis is maintained under healthy conditions and how it is restored in disease. PMID:27587549

  13. Adaptive midlife defense mechanisms and late-life health.

    PubMed

    Malone, Johanna C; Cohen, Shiri; Liu, Sabrina R; Vaillant, George E; Waldinger, Robert J

    2013-07-01

    A growing body of research suggests that personality characteristics relate to physical health; however, this relation ship has primarily been tested in cross-sectional studies that have not followed the participants into old age. The present study utilizes data from a 70-year longitudinal study to prospectively examine the relationship between the adaptive defense mechanisms in midlife and objectively assessed physical health in late life. In addition to examining the direct effect, we test whether social support mediates this relation ship. The sample consisted of 90 men who were followed for over seven decades beginning in late adolescence. Health ratings from medical records were made at three time points (ages 70, 75, and 80). Defense mechanisms were coded from narratives by trained independent raters (Vaillant, Bond, & Vaillant, 1986). Independent raters assessed social supports between ages 50 and 70. More adaptive defenses in midlife were associated with better physical health at all three time points in late life. These relationships were partially mediated by social support. Findings are consistent with the theory that defense maturity is important for building social relationships, which in turn contribute to better late-life physical health. Psychological interventions aimed at improving these domains may be beneficial for physical health.

  14. Gene Expression Analysis Reveals the Concurrent Activation of Proapoptotic and Antioxidant-Defensive Mechanisms in Flavokawain B-Treated Cervical Cancer HeLa Cells.

    PubMed

    Yeap, Swee Keong; Abu, Nadiah; Akthar, Nadeem; Ho, Wan Yong; Ky, Huynh; Tan, Sheau Wei; Alitheen, Noorjahan Banu; Kamarul, Tunku

    2016-07-24

    Flavokawain B (FKB) is known to possess promising anticancer abilities. This is demonstrated in various cancer cell lines including HeLa cells. Cervical cancer is among the most widely diagnosed cancer among women today. Though FKB has been shown to be effective in treating cancer cells, the exact molecular mechanism is still unknown. This study is aimed at understanding the effects of FKB on HeLa cells using a microarray-based mRNA expression profiling and proteome profiling of stress-related proteins. The results of this study suggest that FKB induced cell death through p21-mediated cell cycle arrest and activation of p38. However, concurrent activation of antioxidant-related pathways and iron sequestration pathway followed by activation of ER-resident stress proteins clearly indicate that FKB failed to induce apoptosis in HeLa cells via oxidative stress. This effect implies that the protection of HeLa cells by FKB from H2O2-induced cell death is via neutralization of reactive oxygen species.

  15. The Venturia Apple Pathosystem: Pathogenicity Mechanisms and Plant Defense Responses

    PubMed Central

    Jha, Gopaljee; Thakur, Karnika; Thakur, Priyanka

    2009-01-01

    Venturia inaequalis is the causal agent of apple scab, a devastating disease of apple. We outline several unique features of this pathogen which are useful for molecular genetics studies intended to understand plant-pathogen interactions. The pathogenicity mechanisms of the pathogen and overview of apple defense responses, monogenic and polygenic resistance, and their utilization in scab resistance breeding programs are also reviewed. PMID:20150969

  16. Host defense mechanisms against pneumonia due to Pseudomonas aeruginosa.

    PubMed

    Pennington, J E; Ehrie, M G; Hickey, W F

    1984-01-01

    Pneumonia due to Pseudomonas aeruginosa is associated with unusually high mortalities. Accordingly, efforts to define better the most important components of lung defenses against this infection are justified as a prelude to defining improved management strategies. In this report, a guinea pig model of experimental aspiration pseudomonas pneumonia was employed for studies of cellular and humoral mechanisms of pulmonary defense. Animals treated with cortisone acetate plus cyclophosphamide experienced decreased survival from pneumonia, and survival rates correlated directly with the degree of myelosuppression. Numbers of pulmonary macrophages and polymorphonuclear neutrophils were reduced in drug-treated animals before impairment of macrophage antibacterial function. Thus, a reduction in numbers of phagocytes alone was sufficient to markedly reduce lung defenses. In additional experiments, normal guinea pigs were vaccinated with a lipopolysaccharide pseudomonas vaccine. Improved survival from pneumonia correlated with high titers of type-specific, heat-stable opsonic antibody. It is concluded that adequate numbers of lung phagocytes, plus type-specific opsonic antibody, represent the ideal status for lung defense against P. aeruginosa infection.

  17. Central Amygdala Somatostatin Neurons Gate Passive and Active Defensive Behaviors

    PubMed Central

    Yu, Kai; Garcia da Silva, Pedro; Albeanu, Dinu F.

    2016-01-01

    The central amygdala (CeA) has a key role in learning and expression of defensive responses. Recent studies indicate that somatostatin-expressing (SOM+) neurons in the lateral division of the CeA (CeL) are essential for the acquisition and recall of conditioned freezing behavior, which has been used as an index of defensive response in laboratory animals during Pavlovian fear conditioning. However, how exactly these neurons participate in fear conditioning and whether they contribute to the generation of defensive responses other than freezing remain unknown. Here, using fiber-optic photometry combined with optogenetic and molecular techniques in behaving mice, we show that SOM+ CeL neurons are activated by threat-predicting sensory cues after fear conditioning and that activation of these neurons suppresses ongoing actions and converts an active defensive behavior to a passive response. Furthermore, inhibition of these neurons using optogenetic or molecular methods promotes active defensive behaviors. Our results provide the first in vivo evidence that SOM+ neurons represent a CeL population that acquires learning-dependent sensory responsiveness during fear conditioning and furthermore reveal an important role of these neurons in gating passive versus active defensive behaviors in animals confronted with threat. SIGNIFICANCE STATEMENT The ability to develop adaptive behavioral responses to threat is fundamental for survival. Recent studies indicate that the central lateral amygdala (CeL), in particular its somatostatin-expressing neurons, is crucial for both learning and the expression of defensive response. However, how exactly these neurons participate in such processes remains unclear. Here we show for the first time in behaving mice that the somatostatin-expressing neurons in the CeL acquire learning-dependent responsiveness to sensory cues predicting a threat. Furthermore, our results indicate that these neurons gate the behavioral output of an animal

  18. Department of Defense Education Activity. An Overview.

    ERIC Educational Resources Information Center

    US Department of Defense, 2004

    2004-01-01

    DoDEA operates 223 public schools in 16 districts located in seven states, Puerto Rico, Guam, and 13 foreign countries to serve the children of military service members and Department of Defense civilian employees. Approximately 104,935 students are enrolled in DoDEA schools, with approximately 73,200 students in the DoDDS system, and…

  19. Host-Defense Activities of Cyclotides

    PubMed Central

    Craik, David J.

    2012-01-01

    Cyclotides are plant mini-proteins whose natural function is thought to be to protect plants from pest or pathogens, particularly insect pests. They are approximately 30 amino acids in size and are characterized by a cyclic peptide backbone and a cystine knot arrangement of three conserved disulfide bonds. This article provides an overview of the reported pesticidal or toxic activities of cyclotides, discusses a possible common mechanism of action involving disruption of biological membranes in pest species, and describes methods that can be used to produce cyclotides for potential applications as novel pesticidal agents. PMID:22474571

  20. Defense Mechanisms in Adolescence as Predictors of Adult Personality Disorders.

    PubMed

    Strandholm, Thea; Kiviruusu, Olli; Karlsson, Linnea; Miettunen, Jouko; Marttunen, Mauri

    2016-05-01

    Our study examines whether defense styles and separate defenses in depressed adolescent outpatients predict adult personality disorders (PDs). We obtained data from consecutive adolescent outpatients who participated in the Adolescent Depression Study at baseline and at the 8-year follow-up (N = 140). Defense styles were divided into mature, neurotic, image-distorting, and immature and a secondary set of analyses were made with separate defenses as predictors of a PD diagnosis. Neurotic, image-distorting, and immature defense styles in adolescence were associated with adulthood PDs. Neurotic defense style associated with cluster B diagnosis and image-distorting defense style associated with cluster A diagnosis. Separate defenses of displacement, isolation, and reaction formation were independent predictors of adult PD diagnosis even after adjusting for PD diagnosis in adolescence. Defense styles and separate defenses predict later PDs and could be used in the focusing of treatment interventions for adolescents.

  1. Activated chemical defenses suppress herbivory on freshwater red algae.

    PubMed

    Goodman, Keri M; Hay, Mark E

    2013-04-01

    The rapid life cycles of freshwater algae are hypothesized to suppress selection for chemical defenses against herbivores, but this notion remains untested. Investigations of chemical defenses are rare for freshwater macrophytes and absent for freshwater red algae. We used crayfish to assess the palatability of five freshwater red algae relative to a palatable green alga and a chemically defended aquatic moss. We then assessed the roles of structural, nutritional, and chemical traits in reducing palatability. Both native and non-native crayfish preferred the green alga Cladophora glomerata to four of the five red algae. Batrachospermum helminthosum, Kumanoa holtonii, and Tuomeya americana employed activated chemical defenses that suppressed feeding by 30-60 % following damage to algal tissues. Paralemanea annulata was defended by its cartilaginous structure, while Boldia erythrosiphon was palatable. Activated defenses are thought to reduce ecological costs by expressing potent defenses only when actually needed; thus, activation might be favored in freshwater red algae whose short-lived gametophytes must grow and reproduce rapidly over a brief growing season. The frequency of activated chemical defenses found here (three of five species) is 3-20× higher than for surveys of marine algae or aquatic vascular plants. If typical for freshwater red algae, this suggests that (1) their chemical defenses may go undetected if chemical activation is not considered and (2) herbivory has been an important selective force in the evolution of freshwater Rhodophyta. Investigations of defenses in freshwater rhodophytes contribute to among-system comparisons and provide insights into the generality of plant-herbivore interactions and their evolution.

  2. Defense High-Level Waste Leaching Mechanisms Program. Final report

    SciTech Connect

    Mendel, J.E.

    1984-08-01

    The Defense High-Level Waste Leaching Mechanisms Program brought six major US laboratories together for three years of cooperative research. The participants reached a consensus that solubility of the leached glass species, particularly solubility in the altered surface layer, is the dominant factor controlling the leaching behavior of defense waste glass in a system in which the flow of leachant is constrained, as it will be in a deep geologic repository. Also, once the surface of waste glass is contacted by ground water, the kinetics of establishing solubility control are relatively rapid. The concentrations of leached species reach saturation, or steady-state concentrations, within a few months to a year at 70 to 90/sup 0/C. Thus, reaction kinetics, which were the main subject of earlier leaching mechanisms studies, are now shown to assume much less importance. The dominance of solubility means that the leach rate is, in fact, directly proportional to ground water flow rate. Doubling the flow rate doubles the effective leach rate. This relationship is expected to obtain in most, if not all, repository situations.

  3. The chemical defense ecology of marine unicellular plankton: constraints, mechanisms, and impacts.

    PubMed

    Wolfe, G V

    2000-04-01

    The activities of unicellular microbes dominate the ecology of the marine environment, but the chemical signals that determine behavioral interactions are poorly known. In particular, chemical signals between microbial predators and prey contribute to food selection or avoidance and to defense, factors that probably affect trophic structure and such large-scale features as algal blooms. Using defense as an example, I consider physical constraints on the transmission of chemical information, and strategies and mechanisms that microbes might use to send chemical signals. Chemical signals in a low Re, viscosity-dominated physical environment are transferred by molecular diffusion and laminar advection, and may be perceived at nanomolar levels or lower. Events that occur on small temporal and physical scales in the "near-field" of prey are likely to play a role in cell-cell interactions. On the basis of cost-benefit optimization and the need for rapid activation, I suggest that microbial defense system strategies might be highly dynamic. These strategies include compartmented and activated reactions, utilizing both pulsed release of dissolved signals and contact-activated signals at the cell surface. Bioluminescence and extrusome discharge are two visible manifestations of rapidly activated microbial defenses that may serve as models for other chemical reactions as yet undetected due to the technical problems of measuring transient chemical gradients around single cells. As an example, I detail an algal dimethylsulfoniopropionate (DMSP) cleavage reaction that appears to deter protozoan feeding and explore it as a possible model for a rapidly activated, short-range chemical defense system. Although the exploration of chemical interactions among planktonic microbes is in its infancy, ecological models from macroorganisms provide useful hints of the complexity likely to be found.

  4. Partially resistant Cucurbita pepo showed late onset of the Zucchini yellow mosaic virus infection due to rapid activation of defense mechanisms as compared to susceptible cultivar.

    PubMed

    Nováková, Slavomíra; Flores-Ramírez, Gabriela; Glasa, Miroslav; Danchenko, Maksym; Fiala, Roderik; Skultety, Ludovit

    2015-01-01

    Zucchini yellow mosaic virus (ZYMV) is an emerging viral pathogen in cucurbit-growing areas wordwide. Infection causes significant yield losses in several species of the family Cucurbitaceae. To identify proteins potentially involved with resistance toward infection by the severe ZYMV-H isolate, two Cucurbita pepo cultivars (Zelena susceptible and Jaguar partially resistant) were analyzed using a two-dimensional gel electrophoresis-based proteomic approach. Initial symptoms on leaves (clearing veins) developed 6-7 days post-inoculation (dpi) in the susceptible C. pepo cv. Zelena. In contrast, similar symptoms appeared on the leaves of partially resistant C. pepo cv. Jaguar only after 15 dpi. This finding was confirmed by immune-blot analysis which showed higher levels of viral proteins at 6 dpi in the susceptible cultivar. Leaf proteome analyses revealed 28 and 31 spots differentially abundant between cultivars at 6 and 15 dpi, respectively. The variance early in infection can be attributed to a rapid activation of proteins involved with redox homeostasis in the partially resistant cultivar. Changes in the proteome of the susceptible cultivar are related to the cytoskeleton and photosynthesis.

  5. Partially resistant Cucurbita pepo showed late onset of the Zucchini yellow mosaic virus infection due to rapid activation of defense mechanisms as compared to susceptible cultivar

    PubMed Central

    Nováková, Slavomíra; Flores-Ramírez, Gabriela; Glasa, Miroslav; Danchenko, Maksym; Fiala, Roderik; Skultety, Ludovit

    2015-01-01

    Zucchini yellow mosaic virus (ZYMV) is an emerging viral pathogen in cucurbit-growing areas wordwide. Infection causes significant yield losses in several species of the family Cucurbitaceae. To identify proteins potentially involved with resistance toward infection by the severe ZYMV-H isolate, two Cucurbita pepo cultivars (Zelena susceptible and Jaguar partially resistant) were analyzed using a two-dimensional gel electrophoresis-based proteomic approach. Initial symptoms on leaves (clearing veins) developed 6–7 days post-inoculation (dpi) in the susceptible C. pepo cv. Zelena. In contrast, similar symptoms appeared on the leaves of partially resistant C. pepo cv. Jaguar only after 15 dpi. This finding was confirmed by immune-blot analysis which showed higher levels of viral proteins at 6 dpi in the susceptible cultivar. Leaf proteome analyses revealed 28 and 31 spots differentially abundant between cultivars at 6 and 15 dpi, respectively. The variance early in infection can be attributed to a rapid activation of proteins involved with redox homeostasis in the partially resistant cultivar. Changes in the proteome of the susceptible cultivar are related to the cytoskeleton and photosynthesis. PMID:25972878

  6. The comprehensive assessment of defense style: measuring defense mechanisms in children and adolescents.

    PubMed

    Laor, N; Wolmer, L; Cicchetti, D V

    2001-06-01

    This study introduces the Comprehensive Assessment of Defense Style (CADS), a new method to assess descriptively the defensive behavior of children and adolescents. Parents of 124 children and adolescents referred to a mental health clinic, of 104 nontreated children, and of 15 children whose fathers were treated for posttraumatic stress disorder completed the CADS. Factor analysis of 28 defenses yielded one mature factor, one immature factor of defenses expressed in relations with the environment (other-oriented), and one of defenses expressed in relations with the self (self-oriented). The CADS significantly discriminated between patients and nonpatients. Psychiatric patients used more immature and fewer mature defenses than control subjects, and adolescents used more mature and fewer other-oriented defenses than children. Girls used more mature and fewer other-oriented defenses than boys. The reliability and validity data of the CADS are encouraging. The three defense factors may be implemented for diagnostic and clinical purposes as well as for screening for psychopathology risk in untreated populations.

  7. Psychosexual fixation and defense mechanisms in a sample of young Japanese women: a preliminary study.

    PubMed

    Mogami, Tamiko

    2010-08-01

    The present pilot study examined psychosexual fixations and defense mechanisms in a sample of young Japanese women. The Lexical Rorschach count and the Defense Mechanisms Inventory were administered to 24 female college students. Sadism on the Lexical Rorschach count was positively correlated with Reversal of Affect. Phallic fixation on the Lexical Rorschach count was positively correlated with Projection. Psychoanalytic hypotheses about the associations between psychosexual fixations and defense mechanisms were partially confirmed.

  8. Inducible maize defense mechanisms against the corn borer Sesamia nonagrioides: a transcriptome and biochemical approach.

    PubMed

    Rodríguez, Víctor M; Santiago, Rogelio; Malvar, Rosa Ana; Butrón, Ana

    2012-01-01

    In spite of multiple studies elucidating individual defense mechanisms against stalk borer feeding, little information is available about the plant response to these members of Lepidoptera. Four maize inbred lines were cultivated in a greenhouse and challenged with larvae of the corn borer Sesamia nonagrioides. Transcriptome and biochemical analyses were performed to elucidate the maize response mechanisms to this insect. General plant defense mechanisms were activated, including the jasmonic acid biosynthetic pathway, proteinase inhibitors, and four defense-related transcription factors. Interestingly, gene ontology analysis shows that maize plants undergo cell-wall reorganization after being attacked. These results were confirmed through biochemical analyses showing that the concentration of some cell-wall-related compounds significantly changed after plant infestation in a genotype-dependent way. In conclusion, maize plants respond to the attack of the corn borer S. nonagrioides through cell-wall fortification, activating genes involved in cell-wall organization, which finally is reflected in a higher concentration of some cell-wall components, especially in resistant genotypes.

  9. Change in Coping and Defense Mechanisms across Adulthood: Longitudinal Findings in a European American Sample

    ERIC Educational Resources Information Center

    Diehl, Manfred; Chui, Helena; Hay, Elizabeth L.; Lumley, Mark A.; Grühn, Daniel; Labouvie-Vief, Gisela

    2014-01-01

    This study examined longitudinal changes in coping and defense mechanisms in an age- and gender-stratified sample of 392 European American adults. Nonlinear age-related changes were found for the coping mechanisms of sublimation and suppression and the defense mechanisms of intellectualization, doubt, displacement, and regression. The change…

  10. [The dynamics of forming an active defensive reflex in cats].

    PubMed

    Fokin, V F

    1975-01-01

    Active defensive reflexes were elaborated in cats with pain stimulations of the forepaw by means of an electrical pricking device with a target attached to it. The elaboration was carried out during action of a flickering light used for the convenience of the EEG analysis. Repeated pain stimulation led to elaboration of an aggressive attacking reaction, chiefly manifested in the paw striking the target. At the beginning of the elaboration, passive-defensive reactions were manifest, which did not completely disappear even after formation of a stable attacking reflex. Two types of active defensive reflexes were elaborated: A-type reflex which helped the animal to get rid of the pain stimulation at the very beginning; B-type reflex which prevented the pain stimulation. The difference beteween these two types is discussed.

  11. Ego defense mechanisms in Pakistani medical students: a cross sectional analysis

    PubMed Central

    2010-01-01

    Background Ego defense mechanisms (or factors), defined by Freud as unconscious resources used by the ego to reduce conflict between the id and superego, are a reflection of how an individual deals with conflict and stress. This study assesses the prevalence of various ego defense mechanisms employed by medical students of Karachi, which is a group with higher stress levels than the general population. Methods A questionnaire based cross-sectional study was conducted on 682 students from five major medical colleges of Karachi over 4 weeks in November 2006. Ego defense mechanisms were assessed using the Defense Style Questionnaire (DSQ-40) individually and as grouped under Mature, Immature, and Neurotic factors. Results Lower mean scores of Immature defense mechanisms (4.78) were identified than those for Neurotic (5.62) and Mature (5.60) mechanisms among medical students of Karachi. Immature mechanisms were more commonly employed by males whereas females employed more Neurotic mechanisms than males. Neurotic and Immature defenses were significantly more prevalent in first and second year students. Mature mechanisms were significantly higher in students enrolled in Government colleges than Private institutions (p < 0.05). Conclusions Immature defense mechanisms were less commonly employed than Neurotic and Mature mechanisms among medical students of Karachi. The greater employment of Neurotic defenses may reflect greater stress levels than the general population. Employment of these mechanisms was associated with female gender, enrollment in a private medical college, and students enrolled in the first 2 years of medical school. PMID:20109240

  12. Defense mechanisms of Solanum tuberosum L. in response to attack by plant-pathogenic bacteria.

    PubMed

    Poiatti, Vera A D; Dalmas, Fernando R; Astarita, Leandro V

    2009-01-01

    The natural resistance of plants to disease is based not only on preformed mechanisms, but also on induced mechanisms. The defense mechanisms present in resistant plants may also be found in susceptible ones. This study attempted to analyze the metabolic alterations in plants of the potato Solanum tuberosum L. cv. Agata that were inoculated with the incompatible plant-pathogenic bacteria X. axonopodis and R. solanacearum, and the compatible bacterium E. carotovora. Levels of total phenolic compounds, including the flavonoid group, and the activities of polyphenol oxidase (PPO) and peroxidase (POX) were evaluated. Bacteria compatibility was evaluated by means of infiltration of tubers. The defense response was evaluated in the leaves of the potato plants. Leaves were inoculated depending on their number and location on the stem. Multiple-leaf inoculation was carried out on basal, intermediate, and apical leaves, and single inoculations on intermediate leaves. Leaves inoculated with X. axonopodis and with R. solanacearum showed hypersensitive responses within 24 hours post-inoculation, whereas leaves inoculated with E. carotovora showed disease symptoms. Therefore, the R. solanacearum isolate used in the experiments did not exhibit virulence to this potato cultivar. Regardless of the bacterial treatments, the basal leaves showed higher PPO and POX activities and lower levels of total phenolic compounds and flavonoids, compared to the apical leaves. However, basal and intermediate leaves inoculated with R. solanacearum and X. axonopodis showed increases in total phenolic compounds and flavonoid levels. In general, multiple-leaf inoculation showed the highest levels of total phenolics and flavonoids, whereas the single inoculations resulted in the highest increase in PPO activity. The POX activity showed no significant difference between single- and multiple-leaf inoculations. Plants inoculated with E. carotovora showed no significant increase in defense mechanisms

  13. An Alternative Form of the Defense Mechanisms Inventory: Assessing Chinese University Students

    ERIC Educational Resources Information Center

    Zhang, Li-Fang

    2016-01-01

    To overcome the major weakness in the response format of the Defense Mechanisms Inventory and to use the information most relevant to the population concerned in the present study, an alternative form of the Defense Mechanisms Inventory (DMI-AF) was designed. The 80 Likert-scaled items in the inventory were tested among 385 university students in…

  14. Serine/threonine protein phosphatases: multi-purpose enzymes in control of defense mechanisms

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Serine/threonine protein phosphatases are a group of enzymes involved in the regulation of defense mechanisms in plants. This paper describes the effects of an inhibitor of these enzymes on the expression of all of the genes associated with these defense mechanisms. The results suggest that inhibi...

  15. Activation of Phospholipase A by Plant Defense Elicitors.

    PubMed Central

    Chandra, S.; Heinstein, P. F.; Low, P. S.

    1996-01-01

    Participation of phospholipase A (PLase A) in plant signal transduction has been documented for auxin stimulation of growth but not for elicitation of any plant defense response. In this paper, we report two independent assays for monitoring PLase A induction in plant cells and have used these assays to evaluate whether transduction of defense-related signals might require PLase A activation. Oligogalacturonic acid, a potent elicitor of the soybean (Glycine max) H2O2 burst, was unable to stimulate endogenous PLase A, suggesting that PLase A activation is not an obligate intermediate in the oligogalacturonic acid-induced burst pathway. In contrast, harpin and an extract from the pathogenic fungus Verticillium dahliae both stimulated the oxidative burst and promoted a rapid increase in PLase A activity. To evaluate the possible role of this inducible PLase A activity in transducing the oxidative burst, we tested the effect of chlorpromazine-HCl, a PLase A inhibitor on elicitor-stimulated burst activity. Pretreatment with chloropromazine was found to inhibit the H2O2 burst triggered by V. dahliae extract at the same concentration at which it blocked PLase A activation. In contrast, neither the harpin- nor oligogalacturonic acid-induced burst was altered by addition of chlorpromazine. These data suggest that PLase A stimulation may be important in certain elicitor-induced oxidative bursts (e.g. V. dahliae) and that other elicitors such as oligogalacturonic acid and harpin must operate through independent signaling intermediates to activate the same defense response. PMID:12226235

  16. Partial Activation of SA- and JA-Defensive Pathways in Strawberry upon Colletotrichum acutatum Interaction

    PubMed Central

    Amil-Ruiz, Francisco; Garrido-Gala, José; Gadea, José; Blanco-Portales, Rosario; Muñoz-Mérida, Antonio; Trelles, Oswaldo; de los Santos, Berta; Arroyo, Francisco T.; Aguado-Puig, Ana; Romero, Fernando; Mercado, José-Ángel; Pliego-Alfaro, Fernando; Muñoz-Blanco, Juan; Caballero, José L.

    2016-01-01

    Understanding the nature of pathogen host interaction may help improve strawberry (Fragaria × ananassa) cultivars. Plant resistance to pathogenic agents usually operates through a complex network of defense mechanisms mediated by a diverse array of signaling molecules. In strawberry, resistance to a variety of pathogens has been reported to be mostly polygenic and quantitatively inherited, making it difficult to associate molecular markers with disease resistance genes. Colletotrichum acutatum spp. is a major strawberry pathogen, and completely resistant cultivars have not been reported. Moreover, strawberry defense network components and mechanisms remain largely unknown and poorly understood. Assessment of the strawberry response to C. acutatum included a global transcript analysis, and acidic hormones SA and JA measurements were analyzed after challenge with the pathogen. Induction of transcripts corresponding to the SA and JA signaling pathways and key genes controlling major steps within these defense pathways was detected. Accordingly, SA and JA accumulated in strawberry after infection. Contrastingly, induction of several important SA, JA, and oxidative stress-responsive defense genes, including FaPR1-1, FaLOX2, FaJAR1, FaPDF1, and FaGST1, was not detected, which suggests that specific branches in these defense pathways (those leading to FaPR1-2, FaPR2-1, FaPR2-2, FaAOS, FaPR5, and FaPR10) were activated. Our results reveal that specific aspects in SA and JA dependent signaling pathways are activated in strawberry upon interaction with C. acutatum. Certain described defense-associated transcripts related to these two known signaling pathways do not increase in abundance following infection. This finding suggests new insight into a specific putative molecular strategy for defense against this pathogen. PMID:27471515

  17. Partial Activation of SA- and JA-Defensive Pathways in Strawberry upon Colletotrichum acutatum Interaction.

    PubMed

    Amil-Ruiz, Francisco; Garrido-Gala, José; Gadea, José; Blanco-Portales, Rosario; Muñoz-Mérida, Antonio; Trelles, Oswaldo; de Los Santos, Berta; Arroyo, Francisco T; Aguado-Puig, Ana; Romero, Fernando; Mercado, José-Ángel; Pliego-Alfaro, Fernando; Muñoz-Blanco, Juan; Caballero, José L

    2016-01-01

    Understanding the nature of pathogen host interaction may help improve strawberry (Fragaria × ananassa) cultivars. Plant resistance to pathogenic agents usually operates through a complex network of defense mechanisms mediated by a diverse array of signaling molecules. In strawberry, resistance to a variety of pathogens has been reported to be mostly polygenic and quantitatively inherited, making it difficult to associate molecular markers with disease resistance genes. Colletotrichum acutatum spp. is a major strawberry pathogen, and completely resistant cultivars have not been reported. Moreover, strawberry defense network components and mechanisms remain largely unknown and poorly understood. Assessment of the strawberry response to C. acutatum included a global transcript analysis, and acidic hormones SA and JA measurements were analyzed after challenge with the pathogen. Induction of transcripts corresponding to the SA and JA signaling pathways and key genes controlling major steps within these defense pathways was detected. Accordingly, SA and JA accumulated in strawberry after infection. Contrastingly, induction of several important SA, JA, and oxidative stress-responsive defense genes, including FaPR1-1, FaLOX2, FaJAR1, FaPDF1, and FaGST1, was not detected, which suggests that specific branches in these defense pathways (those leading to FaPR1-2, FaPR2-1, FaPR2-2, FaAOS, FaPR5, and FaPR10) were activated. Our results reveal that specific aspects in SA and JA dependent signaling pathways are activated in strawberry upon interaction with C. acutatum. Certain described defense-associated transcripts related to these two known signaling pathways do not increase in abundance following infection. This finding suggests new insight into a specific putative molecular strategy for defense against this pathogen.

  18. Anomalies and specific functions in the clinical identification of defense mechanisms.

    PubMed

    Perry, J Christopher

    2014-05-01

    Standard teaching about defense mechanisms generally focuses on definitions, which do not readily aid the clinician in identifying defenses whenever individuals use them. This report demonstrates a process by which the clinician can identify when a defense is used, which ones are likely being used, and with what aim. Clinicians first notice that a defense may be operating whenever the other individual presents with anomalies in the expression of affect, behavior, speech, or its content. Some of these anomalies are described. Next, to identify the specific defense or general level of defensive functioning used, the clinician must identify the specific function of the defense in context using a process of guided clinical inference. This report examines 2 verbatim examples from recorded interviews of one case to demonstrate this process. The examples present a microcosm of clinical concerns that have a surprising relationship to the individual's course and prognosis.

  19. Change in coping and defense mechanisms across adulthood: longitudinal findings in a European American sample.

    PubMed

    Diehl, Manfred; Chui, Helena; Hay, Elizabeth L; Lumley, Mark A; Grühn, Daniel; Labouvie-Vief, Gisela

    2014-02-01

    This study examined longitudinal changes in coping and defense mechanisms in an age- and gender-stratified sample of 392 European American adults. Nonlinear age-related changes were found for the coping mechanisms of sublimation and suppression and the defense mechanisms of intellectualization, doubt, displacement, and regression. The change trajectories for sublimation and suppression showed that their use increased from adolescence to late middle age and early old age and remained mostly stable into late old age. The change trajectory for intellectualization showed that the use of this defense mechanism increased from adolescence to middle age, remained stable until late midlife, and started to decline thereafter. The defense mechanisms of doubt, displacement, and regression showed decreases from adolescence until early old age, with increases occurring again after the age of 65. Linear age-related decreases were found for the coping mechanism of ego regression and the defense mechanisms of isolation and rationalization. Gender and socioeconomic status were associated with the mean levels of several coping and defense mechanisms but did not moderate age-related changes. Increases in ego level were associated with increased use of the defense mechanism intellectualization and decreased use of the defense mechanisms of doubt and displacement. Overall, these findings in a European American sample suggest that most individuals showed development in the direction of more adaptive and less maladaptive coping and defense strategies from adolescence until late middle age or early old age. However, in late old age this development was reversed, presenting potential challenges to the adaptive capacity of older adults.

  20. Activation of Hepatic STAT3 Maintains Pulmonary Defense during Endotoxemia

    PubMed Central

    Hilliard, Kristie L.; Allen, Eri; Traber, Katrina E.; Kim, Yuri; Wasserman, Gregory A.; Jones, Matthew R.; Mizgerd, Joseph P.

    2015-01-01

    Pneumonia and infection-induced sepsis are worldwide public health concerns. Both pathologies elicit systemic inflammation and induce a robust acute-phase response (APR). Although APR activation is well regarded as a hallmark of infection, the direct contributions of liver activation to pulmonary defense during sepsis remain unclear. By targeting STAT3-dependent acute-phase changes in the liver, we evaluated the role of liver STAT3 activity in promoting host defense in the context of sepsis and pneumonia. We employed a two-hit endotoxemia/pneumonia model, whereby administration of 18 h of intraperitoneal lipopolysaccharide (LPS; 5 mg/kg of body weight) was followed by intratracheal Escherichia coli (106 CFU) in wild-type mice or those lacking hepatocyte STAT3 (hepSTAT3−/−). Pneumonia alone (without endotoxemia) was effectively controlled in the absence of liver STAT3. Following endotoxemia and pneumonia, however, hepSTAT3−/− mice, with significantly reduced levels of circulating and airspace acute-phase proteins, exhibited significantly elevated lung and blood bacterial burdens and mortality. These data suggested that STAT3-dependent liver responses are necessary to promote host defense. While neither recruited airspace neutrophils nor lung injury was altered in endotoxemic hepSTAT3−/− mice, alveolar macrophage reactive oxygen species generation was significantly decreased. Additionally, bronchoalveolar lavage fluid from this group of hepSTAT3−/− mice allowed greater bacterial growth ex vivo. These results suggest that hepatic STAT3 activation promotes both cellular and humoral lung defenses. Taken together, induction of liver STAT3-dependent gene expression programs is essential to countering the deleterious consequences of sepsis on pneumonia susceptibility. PMID:26216424

  1. Guardian of the Human Genome: Host Defense Mechanisms against LINE-1 Retrotransposition

    PubMed Central

    Ariumi, Yasuo

    2016-01-01

    Long interspersed element type 1 (LINE-1, L1) is a mobile genetic element comprising about 17% of the human genome, encoding a newly identified ORF0 with unknown function, ORF1p with RNA-binding activity and ORF2p with endonuclease and reverse transcriptase activities required for L1 retrotransposition. L1 utilizes an endonuclease (EN) to insert L1 cDNA into target DNA, which induces DNA double-strand breaks (DSBs). The ataxia-telangiectasia mutated (ATM) is activated by DSBs and subsequently the ATM-signaling pathway plays a role in regulating L1 retrotransposition. In addition, the host DNA repair machinery such as non-homologous end-joining (NHEJ) repair pathway is also involved in L1 retrotransposition. On the other hand, L1 is an insertional mutagenic agent, which contributes to genetic change, genomic instability, and tumorigenesis. Indeed, high-throughput sequencing-based approaches identified numerous tumor-specific somatic L1 insertions in variety of cancers, such as colon cancer, breast cancer, and hepatocellular carcinoma (HCC). In fact, L1 retrotransposition seems to be a potential factor to reduce the tumor suppressive property in HCC. Furthermore, recent study demonstrated that a specific viral-human chimeric transcript, HBx-L1, contributes to hepatitis B virus (HBV)-associated HCC. In contrast, host cells have evolved several defense mechanisms protecting cells against retrotransposition including epigenetic regulation through DNA methylation and host defense factors, such as APOBEC3, MOV10, and SAMHD1, which restrict L1 mobility as a guardian of the human genome. In this review, I focus on somatic L1 insertions into the human genome in cancers and host defense mechanisms against deleterious L1 insertions. PMID:27446907

  2. Object relations and defense mechanisms of a psychopathic serial sexual homicide perpetrator: a TAT analysis.

    PubMed

    Porcerelli, J H; Abramsky, M F; Hibbard, S; Kamoo, R

    2001-08-01

    The case of a 24-year-old African American man who committed serial sexual homicide and who met criteria (Hare, 1991) for psychopathy is presented. His Thematic Apperception Test (Murray, 1943) responses were used to code key aspects of personality organization--object relations and defense mechanisms--via the Social Cognition and Object Relations Scale (Westen, Lohr, Silk, & Kerber, 1989) and the Defense Mechanisms Manual (Cramer, 1991), respectively. Severe object relations pathology and a reliance on the defense mechanism of immature projection and immature denial are noted. Findings are relatively consistent with previous psychodynamic Rorschach studies of psychopathic sexual homicide perpetrators (Gacono, Meloy, & Bridges, 2000; Meloy, Gacono, & Kenney, 1994).

  3. Mechanical defenses of plant extrafloral nectaries against herbivory

    PubMed Central

    Gish, Moshe; Mescher, Mark C.; De Moraes, Consuelo M.

    2016-01-01

    ABSTRACT Extrafloral nectaries play an important role in plant defense against herbivores by providing nectar rewards that attract ants and other carnivorous insects. However, extrafloral nectaries can themselves be targets of herbivory, in addition to being exploited by nectar-robbing insects that do not provide defensive services. We recently found that the extrafloral nectaries of Vicia faba plants, as well as immediately adjacent tissues, exhibit high concentrations of chemical toxins, apparently as a defense against herbivory. Here we report that the nectary tissues of this plant also exhibit high levels of structural stiffness compared to surrounding tissues, likely due to cell wall lignification and the concentration of calcium oxalate crystals in nectary tissues, which may provide an additional deterrent to herbivore feeding on nectary tissues. PMID:27489584

  4. Immature psychological defense mechanisms are associated with greater personal importance of junk food, alcohol, and television.

    PubMed

    Costa, Rui Miguel; Brody, Stuart

    2013-10-30

    Immature psychological defense mechanisms are psychological processes that play an important role in suppressing emotional awareness and contribute to psychopathology. In addition, unhealthy food, television viewing, and alcohol consumption can be among the means to escape self-awareness. In contrast, engaging in, and responding fully to specifically penile-vaginal intercourse (PVI) is associated with indices of better emotional regulation, including less use of immature defense mechanisms. There was a lack of research on the association of immature defense mechanisms with personal importance of junk food, alcohol, television, PVI, and noncoital sex. In an online survey, 334 primarily Scottish women completed the Defense Style Questionnaire (DSQ-40), and rated the personal importance of junk food, alcohol, television, PVI, and noncoital sex. Immature defense mechanisms correlated with importance of junk food, alcohol, and television. Importance of PVI correlated with mature defenses, and less use of some component immature defenses. Importance of alcohol correlated with importance of junk food, television, and noncoital sex. Importance of junk food was correlated with importance of television and noncoital sex. The findings are discussed in terms of persons with poorer self-regulatory abilities having more interest in junk food, television, and alcohol, and less interest in PVI.

  5. Erwinia carotovora elicitors and Botrytis cinerea activate defense responses in Physcomitrella patens

    PubMed Central

    Ponce de León, Inés; Oliver, Juan Pablo; Castro, Alexandra; Gaggero, Carina; Bentancor, Marcel; Vidal, Sabina

    2007-01-01

    Background Vascular plants respond to pathogens by activating a diverse array of defense mechanisms. Studies with these plants have provided a wealth of information on pathogen recognition, signal transduction and the activation of defense responses. However, very little is known about the infection and defense responses of the bryophyte, Physcomitrella patens, to well-studied phytopathogens. The purpose of this study was to determine: i) whether two representative broad host range pathogens, Erwinia carotovora ssp. carotovora (E.c. carotovora) and Botrytis cinerea (B. cinerea), could infect Physcomitrella, and ii) whether B. cinerea, elicitors of a harpin (HrpN) producing E.c. carotovora strain (SCC1) or a HrpN-negative strain (SCC3193), could cause disease symptoms and induce defense responses in Physcomitrella. Results B. cinerea and E.c. carotovora were found to readily infect Physcomitrella gametophytic tissues and cause disease symptoms. Treatments with B. cinerea spores or cell-free culture filtrates from E.c. carotovoraSCC1 (CF(SCC1)), resulted in disease development with severe maceration of Physcomitrella tissues, while CF(SCC3193) produced only mild maceration. Although increased cell death was observed with either the CFs or B. cinerea, the occurrence of cytoplasmic shrinkage was only visible in Evans blue stained protonemal cells treated with CF(SCC1) or inoculated with B. cinerea. Most cells showing cytoplasmic shrinkage accumulated autofluorescent compounds and brown chloroplasts were evident in a high proportion of these cells. CF treatments and B. cinerea inoculation induced the expression of the defense-related genes: PR-1, PAL, CHS and LOX. Conclusion B. cinerea and E.c. carotovora elicitors induce a defense response in Physcomitrella, as evidenced by enhanced expression of conserved plant defense-related genes. Since cytoplasmic shrinkage is the most common morphological change observed in plant PCD, and that harpins and B. cinerea induce this

  6. Study of defensive methods and mechanisms in developmental, emotional (internalization), and disruptive behavior (externalization) disorders.

    PubMed

    Jamilian, H R; Zamani, N; Darvishi, M; Khansari, M R

    2014-09-18

    We need to find a way for adaptation with inherent unpleasantness of being human condition and conflicts that it caused, as we did not fail. Methods that we used for adaptation are named defense. This research have performed with the aim of study and compare defensive mechanisms and methods of Developmental, Emotional (Internalization), and Disruptive behavior (Externalization) disorders. Method, sample of this research included 390 family that are by available sampling method are selected. Tools of research were structured clinical interview of forth cognitive and statistical guide of psychopathic disorders for axis I and the way used for assess defensive mechanisms is defensive method 40 question's questionnaires of Andrews (1993). The data are compared by statistical methods comparison of averages and one way variance analysis and HSD tests and results show that undeveloped defensive mechanisms in by developmental disorder family (25.2 ± 3.7) mean and standard deviation, it is most used mechanism and in disruptive behavior disorder family by (11.2 ± 1.9) mean and standard deviation is used least mechanism and in developed mechanism of emotional disorder family by (7.8 ± 3.1) mean and standard deviation is most used mechanism and in developmental disorder family by (4.3 ± 1.5) mean and standard deviation is least mechanism in neuroticism patient, social phobia affected emotional disorder family (15.6 ± 2.6) and disruptive behavior disorder family have least mean and standard deviation (9.2 ± 1.7) (p< 0.005). Recent research shows significant of study defensive mechanism in psychopathic family of disorder children that affecting on the way of life of persons and interpersonal and intrapersonal relations and method of solving problem in family of them in life, so defensive mechanisms require more attention.

  7. Overexpression of Pto activates defense responses and confers broad resistance.

    PubMed Central

    Tang, X; Xie, M; Kim, Y J; Zhou, J; Klessig, D F; Martin, G B

    1999-01-01

    The tomato disease resistance (R) gene Pto specifies race-specific resistance to the bacterial pathogen Pseudomonas syringae pv tomato carrying the avrPto gene. Pto encodes a serine/threonine protein kinase that is postulated to be activated by a physical interaction with the AvrPto protein. Here, we report that overexpression of Pto in tomato activates defense responses in the absence of the Pto-AvrPto interaction. Leaves of three transgenic tomato lines carrying the cauliflower mosaic virus 35S::Pto transgene exhibited microscopic cell death, salicylic acid accumulation, and increased expression of pathogenesis-related genes. Cell death in these plants was limited to palisade mesophyll cells and required light for induction. Mesophyll cells of 35S::Pto plants showed the accumulation of autofluorescent compounds, callose deposition, and lignification. When inoculated with P. s. tomato without avrPto, all three 35S::Pto lines displayed significant resistance and supported less bacterial growth than did nontransgenic lines. Similarly, the 35S::Pto lines also were more resistant to Xanthomonas campestris pv vesicatoria and Cladosporium fulvum. These results demonstrate that defense responses and general resistance can be activated by the overexpression of an R gene. PMID:9878629

  8. Change in children's externalizing and internalizing behavior problems: the role of defense mechanisms.

    PubMed

    Cramer, Phebe

    2015-03-01

    This study investigates the relation of defense mechanism to children's externalizing and internalizing behavior problems, as assessed from mothers' report at age 9 and 12 years, based on archival data. The defense mechanisms of denial, projection, and identification were assessed from Thematic Apperception Test stories told by the children at age 9 years, using the Defense Mechanism Manual (Cramer, The development of defense mechanisms: Theory, research and assessment. New York: Springer-Verlag, 1991a; Protecting the self: Defense mechanisms in action. New York: Guilford Press, 2006). The results showed that the use of identification predicted a decrease in externalizing behaviors between age 9 and 12 years. In contrast, change in internalizing behaviors was not predicted by defense use, but the use of projection was related to fewer internalizing behaviors at both ages. These findings are consistent with the idea that behavioral intervention stressing self-regulation can be effective in reducing externalizing problems, but internalizing problems require an intervention that is sensitive to the underlying behavioral inhibition in these children.

  9. Active, Non-Intrusive Inspection Technologies for Homeland Defense

    SciTech Connect

    James L. Jones

    2003-06-01

    Active, non-intrusive inspection or interrogation technologies have been used for 100 years - with the primary focus being radiographic imaging. During the last 50 years, various active interrogation systems have been investigated and most have revealed many unique and interesting capabilities and advantages that have already benefited the general public. Unfortunately, except for medical and specific industrial applications, these unique capabilities have not been widely adopted, largely due to the complexity of the technology, the overconfident reliance on passive detection systems to handle most challenges, and the unrealistic public concerns regarding radiation safety issues for a given active inspection deployment. The unique homeland security challenges facing the United States today are inviting more "out-of-the-box" solutions and are demanding the effective technological solutions that only active interrogation systems can provide. While revolutionary new solutions are always desired, these technology advancements are rare, and when found, usually take a long time to fully understand and implement for a given application. What's becoming more evident is that focusing on under-developed, but well-understood, active inspection technologies can provide many of the needed "out-of-the-box" solutions. This paper presents a brief historical overview of active interrogation. It identifies some of the major homeland defense challenges being confronted and the commercial and research technologies presently available and being pursued. Finally, the paper addresses the role of the Idaho National Engineering and Environmental Laboratory and its partner, the Idaho Accelerator Center at Idaho State University, in promoting and developing active inspection technologies for homeland defense.

  10. Triiodothyronine and melatonin influence antioxidant defense mechanism in a teleost Anabas testudineus (Bloch): in vitro study.

    PubMed

    Sreejith, P; Beyo, R S; Divya, L; Vijayasree, A S; Manju, M; Oommen, O V

    2007-06-01

    The effect of the hormones triiodothyronine (T3) and melatonin on antioxidant defense system was studied in 6-propyl thiouracil (6-PTU)-treated or photoperiod-exposed teleost Anabas testudineus. 6-PTU (2 microg/g) treatment or photoperiod exposure (24 h) increased malondialdehyde (MDA) and conjugated dienes (CD) concentrations, indicating increased lipid peroxidation (LPO) in the experimental conditions. T3 or melatonin (10(-6) M) treatment for 15 min in vitro in PTU-treated fish reversed the activity of superoxide dismutase (SOD), catalase and glutathione content. T3-treated group showed no change in glutathione peroxidase (GPx) activity, whereas melatonin treatment decreased its activity. T3 inhibited glutathione reductase (GR) activity. Photoperiod exposure (physiological pinealotomy) induced a stressful situation in this teleost, as evidenced by LPO products and antioxidant enzyme activities. Melatonin and T3 treatment for 15 min in vitro also reversed the effect of photoperiod on peroxidation products and the SOD and catalase activities. GR activity decreased in photoperiod-exposed group and melatonin and T3 treatment reversed the activities. The antioxidant enzymes responded to the stress situation after 6-PTU treatment and photoperiod exposure by altering their activities. The study suggested an independent effect of T3 and melatonin on antioxidant defence mechanism in different physiological situations in fish.

  11. 77 FR 76938 - Defense Federal Acquisition Regulation Supplement: Contracting Activity Updates (DFARS Case 2012...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-31

    ... activities from DFARS 202.101, Definitions, to a new DFARS PGI section at 202.101, Definitions. These... available regulatory alternatives and, if regulation is necessary, to select regulatory approaches that... Agency, the Defense Logistics Agency, the Defense Security Cooperation Agency, the Defense...

  12. HOST DEFENSE AGAINST BACTERIAL ENDOTOXEMIA: MECHANISM IN NORMAL ANIMALS

    PubMed Central

    Skarnes, Robert C.

    1970-01-01

    The present study defines the early response of normal rabbits to the intravenous injection of a single, sublethal dose of endotoxin. Within the first few hours following endotoxin there occurs in the circulating plasma of recipients a decrease in ionized calcium, a threefold increase in the heat-stable, organo-phosphate-resistant esterase level, and a striking increase in the endotoxin-detoxifying capacity. These results are fully consistent with the thesis that circulating plasma represents a principal site of detoxification and that plasma esterases of the nonspecific, carboxylic type are of major concern in defense against circulating endotoxins. PMID:4994446

  13. [Inflammasome: activation mechanisms].

    PubMed

    Suárez, Raibel; Buelvas, Neudo

    2015-03-01

    Inflammation is a rapid biologic response of the immune system in vascular tissues, directed to eliminate stimuli capable of causing damage and begin the process of repair. The macromolecular complexes known as "inflammasomes" are formed by a receptor, either NOD (NLR) or ALR, the receptor absent in melanoma 2 (AIM2). In addition, the inflammasome is formed by the speck-like protein associated to apoptosis (ASC) and procaspase-1, that may be activated by variations in the ionic and intracellular and extracellular ATP concentrations; and the loss of stabilization of the fagolisosomme by internalization of insoluble crystals and redox mechanisms. As a result, there is activation of the molecular platform and the processing of inflammatory prointerleukins to their active forms. There are two modalities of activation of the inflammasome: canonical and non-canonical, both capable of generating effector responses. Recent data associate NLRP 3, IL-1β and IL-18 in the pathogenesis of a variety of diseases, including atherosclerosis, type II diabetes, hyperhomocysteinemia, gout, malaria and hypertension. The inflammasome cascade is emerging as a new chemotherapeutic target in these diseases. In this review we shall discuss the mechanisms of activation and regulation of the inflammasome that stimulate, modulate and resolve inflammation.

  14. Cellular defense mechanisms against lead toxicity in the vascular system.

    PubMed

    Shinkai, Yasuhiro; Kaji, Toshiyuki

    2012-01-01

    Lead is a toxic heavy metal that can cause a range of health problems. In this context, the vascular system is a particular target of the deleterious effects of lead. Lead exerts its toxicity through substitution of other divalent cations such as calcium and zinc, resulting in disruption of homeostasis. Based on the evidence that lead up-regulates endoplasmic reticulum (ER) chaperone glucose-regulated protein 78 (GRP78) and/or antioxidant proteins such as hemeoxygenase-1, it is believed that the heavy metal is able to induce ER and/or oxidative stress in cells. These events also suggest that the unfolded protein response (UPR) system and the antioxidant defense system Kelch-like ECH-associated protein 1-nuclear factor (NF)-E2-related factor 2 (Keap1-Nrf2) play a critical role in adaptive response to lead. In this review, we summarize recent progress in lead toxicity in terms of cellular defense systems, including stress proteins and transcription factors involved in the vascular system.

  15. Physcomitrella patens activates reinforcement of the cell wall, programmed cell death and accumulation of evolutionary conserved defense signals...upon Botrytis cinerea infection

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The moss Physcomitrella patens is an evolutionarily basal model system suitable to analyze plant defense responses activated after pathogen assault. Upon infection with the necrotroph Botrytis cinerea (B. cinerea), several defense mechanisms are induced in P. patens, including the fortification of t...

  16. An empirical look at the Defense Mechanism Test (DMT): reliability and construct validity.

    PubMed

    Ekehammar, Bo; Zuber, Irena; Konstenius, Marja-Liisa

    2005-07-01

    Although the Defense Mechanism Test (DMT) has been in use for almost half a century, there are still quite contradictory views about whether it is a reliable instrument, and if so, what it really measures. Thus, based on data from 39 female students, we first examined DMT inter-coder reliability by analyzing the agreement among trained judges in their coding of the same DMT protocols. Second, we constructed a "parallel" photographic picture that retained all structural characteristic of the original and analyzed DMT parallel-test reliability. Third, we examined the construct validity of the DMT by (a) employing three self-report defense-mechanism inventories and analyzing the intercorrelations between DMT defense scores and corresponding defenses in these instruments, (b) studying the relationships between DMT responses and scores on trait and state anxiety, and (c) relating DMT-defense scores to measures of self-esteem. The main results showed that the DMT can be coded with high reliability by trained coders, that the parallel-test reliability is unsatisfactory compared to traditional psychometric standards, that there is a certain generalizability in the number of perceptual distortions that people display from one picture to another, and that the construct validation provided meager empirical evidence for the conclusion that the DMT measures what it purports to measure, that is, psychological defense mechanisms.

  17. Involvement of metabolites in early defense mechanism of oil palm (Elaeis guineensis Jacq.) against Ganoderma disease.

    PubMed

    Nusaibah, S A; Siti Nor Akmar, A; Idris, A S; Sariah, M; Mohamad Pauzi, Z

    2016-12-01

    Understanding the mechanism of interaction between the oil palm and its key pathogen, Ganoderma spp. is crucial as the disease caused by this fungal pathogen leads to a major loss of revenue in leading palm oil producing countries in Southeast Asia. Here in this study, we assess the morphological and biochemical changes in Ganoderma disease infected oil palm seedling roots in both resistant and susceptible progenies. Rubber woodblocks fully colonized by G. boninense were applied as a source of inoculum to artificially infect the roots of resistant and susceptible oil palm progenies. Gas chromatography-mass spectrometry was used to measure an array of plant metabolites in 100 resistant and susceptible oil palm seedling roots treated with pathogenic Ganoderma boninense fungus. Statistical effects, univariate and multivariate analyses were used to identify key-Ganoderma disease associated metabolic agitations in both resistant and susceptible oil palm root tissues. Ganoderma disease related defense shifts were characterized based on (i) increased antifungal activity in crude extracts, (ii) increased lipid levels, beta- and gamma-sitosterol particularly in the resistant progeny, (iii) detection of heterocyclic aromatic organic compounds, benzo [h] quinoline, pyridine, pyrimidine (iv) elevation in antioxidants, alpha- and beta-tocopherol (iv) degraded cortical cell wall layers, possibly resulting from fungal hydrolytic enzyme activity needed for initial penetration. The present study suggested that plant metabolites mainly lipids and heterocyclic aromatic organic metabolites could be potentially involved in early oil palm defense mechanism against G. boninense infection, which may also highlight biomarkers for disease detection, treatment, development of resistant variety and monitoring.

  18. Mechanically Activated Ion Channels

    PubMed Central

    Ranade, Sanjeev S.; Syeda, Ruhma; Patapoutian, Ardem

    2015-01-01

    Mechanotransduction, the conversion of physical forces into biochemical signals, is an essential component of numerous physiological processes including not only conscious senses of touch and hearing, but also unconscious senses such as blood pressure regulation. Mechanically activated (MA) ion channels have been proposed as sensors of physical force, but the identity of these channels and an understanding of how mechanical force is transduced has remained elusive. A number of recent studies on previously known ion channels along with the identification of novel MA ion channels have greatly transformed our understanding of touch and hearing in both vertebrates and invertebrates. Here, we present an updated review of eukaryotic ion channel families that have been implicated in mechanotransduction processes and evaluate the qualifications of the candidate genes according to specified criteria. We then discuss the proposed gating models for MA ion channels and highlight recent structural studies of mechanosensitive potassium channels. PMID:26402601

  19. Mechanically Activated Ion Channels.

    PubMed

    Ranade, Sanjeev S; Syeda, Ruhma; Patapoutian, Ardem

    2015-09-23

    Mechanotransduction, the conversion of physical forces into biochemical signals, is essential for various physiological processes such as the conscious sensations of touch and hearing, and the unconscious sensation of blood flow. Mechanically activated (MA) ion channels have been proposed as sensors of physical force, but the identity of these channels and an understanding of how mechanical force is transduced has remained elusive. A number of recent studies on previously known ion channels along with the identification of novel MA ion channels have greatly transformed our understanding of touch and hearing in both vertebrates and invertebrates. Here, we present an updated review of eukaryotic ion channel families that have been implicated in mechanotransduction processes and evaluate the qualifications of the candidate genes according to specified criteria. We then discuss the proposed gating models for MA ion channels and highlight recent structural studies of mechanosensitive potassium channels.

  20. The Rice Transcription Factor WRKY53 Suppresses Herbivore-Induced Defenses by Acting as a Negative Feedback Modulator of Mitogen-Activated Protein Kinase Activity1

    PubMed Central

    Hu, Lingfei; Ye, Meng; Zhang, Tongfang; Zhou, Guoxin; Wang, Qi; Lu, Jing

    2015-01-01

    The mechanisms by which herbivore-attacked plants activate their defenses are well studied. By contrast, little is known about the regulatory mechanisms that allow them to control their defensive investment and avoid a defensive overshoot. We characterized a rice (Oryza sativa) WRKY gene, OsWRKY53, whose expression is rapidly induced upon wounding and induced in a delayed fashion upon attack by the striped stem borer (SSB) Chilo suppressalis. The transcript levels of OsWRKY53 are independent of endogenous jasmonic acid but positively regulated by the mitogen-activated protein kinases OsMPK3/OsMPK6. OsWRKY53 physically interacts with OsMPK3/OsMPK6 and suppresses their activity in vitro. By consequence, it modulates the expression of defensive, MPK-regulated WRKYs and thereby reduces jasmonic acid, jasmonoyl-isoleucine, and ethylene induction. This phytohormonal reconfiguration is associated with a reduction in trypsin protease inhibitor activity and improved SSB performance. OsWRKY53 is also shown to be a negative regulator of plant growth. Taken together, these results show that OsWRKY53 functions as a negative feedback modulator of MPK3/MPK6 and thereby acts as an early suppressor of induced defenses. OsWRKY53 therefore enables rice plants to control the magnitude of their defensive investment during early signaling. PMID:26453434

  1. NVLAP activities at Department of Defense calibration laboratories

    SciTech Connect

    Schaeffer, D.M.

    1993-12-31

    There are 367 active radiological instrument calibration laboratories within the U.S. Department of Defense (DoD). Each of the four services in DoD manages, operates, and certifies the technical proficiency and competency of those laboratories under their cognizance. Each service has designated secondary calibration laboratories to trace all calibration source standards to the National Institute of Standards and Technology. Individual service radiological calibration programs and capabilities, present and future, are described, as well as the measurement quality assurance (MQA) processes for their traceability. National Voluntary Laboratory Accreditation Program (NVLAP) programs for dosimetry systems are briefly summarized. Planned NVLAP accreditation of secondary laboratories is discussed in the context of current technical challenges and future efforts.

  2. Multiple Different Defense Mechanisms Are Activated in the Young Transgenic Tobacco Plants Which Express the Full Length Genome of the Tobacco Mosaic Virus, and Are Resistant against this Virus

    PubMed Central

    Jada, Balaji; Soitamo, Arto J.; Siddiqui, Shahid Aslam; Murukesan, Gayatri; Aro, Eva-Mari; Salakoski, Tapio; Lehto, Kirsi

    2014-01-01

    Previously described transgenic tobacco lines express the full length infectious Tobacco mosaic virus (TMV) genome under the 35S promoter (Siddiqui et al., 2007. Mol Plant Microbe Interact, 20: 1489–1494). Through their young stages these plants exhibit strong resistance against both the endogenously expressed and exogenously inoculated TMV, but at the age of about 7–8 weeks they break into TMV infection, with typical severe virus symptoms. Infections with some other viruses (Potato viruses Y, A, and X) induce the breaking of the TMV resistance and lead to synergistic proliferation of both viruses. To deduce the gene functions related to this early resistance, we have performed microarray analysis of the transgenic plants during the early resistant stage, and after the resistance break, and also of TMV-infected wild type tobacco plants. Comparison of these transcriptomes to those of corresponding wild type healthy plants indicated that 1362, 1150 and 550 transcripts were up-regulated in the transgenic plants before and after the resistance break, and in the TMV-infected wild type tobacco plants, respectively, and 1422, 1200 and 480 transcripts were down-regulated in these plants, respectively. These transcriptome alterations were distinctly different between the three types of plants, and it appears that several different mechanisms, such as the enhanced expression of the defense, hormone signaling and protein degradation pathways contributed to the TMV-resistance in the young transgenic plants. In addition to these alterations, we also observed a distinct and unique gene expression alteration in these plants, which was the strong suppression of the translational machinery. This may also contribute to the resistance by slowing down the synthesis of viral proteins. Viral replication potential may also be suppressed, to some extent, by the reduction of the translation initiation and elongation factors eIF-3 and eEF1A and B, which are required for the TMV

  3. In Defense of a Heuristic Interpretation of Quantum Mechanics

    ERIC Educational Resources Information Center

    Healy, Eamonn F.

    2010-01-01

    Although the presentation of quantum mechanics found in traditional textbooks is intellectually well founded, it suffers from a number of deficiencies. Specifically introducing quantum mechanics as a solution to the arcane dilemma, the ultraviolet catastrophe, does little to impress a nonscientific audience of the tremendous paradigmatic shift…

  4. Sustained mitogen-activated protein kinase activation reprograms defense metabolism and phosphoprotein profile in Arabidopsis thaliana.

    PubMed

    Lassowskat, Ines; Böttcher, Christoph; Eschen-Lippold, Lennart; Scheel, Dierk; Lee, Justin

    2014-01-01

    Mitogen-activated protein kinases (MAPKs) target a variety of protein substrates to regulate cellular signaling processes in eukaryotes. In plants, the number of identified MAPK substrates that control plant defense responses is still limited. Here, we generated transgenic Arabidopsis thaliana plants with an inducible system to simulate in vivo activation of two stress-activated MAPKs, MPK3, and MPK6. Metabolome analysis revealed that this artificial MPK3/6 activation (without any exposure to pathogens or other stresses) is sufficient to drive the production of major defense-related metabolites, including various camalexin, indole glucosinolate and agmatine derivatives. An accompanying (phospho)proteome analysis led to detection of hundreds of potential phosphoproteins downstream of MPK3/6 activation. Besides known MAPK substrates, many candidates on this list possess typical MAPK-targeted phosphosites and in many cases, the corresponding phosphopeptides were detected by mass spectrometry. Notably, several of these putative phosphoproteins have been reported to be associated with the biosynthesis of antimicrobial defense substances (e.g., WRKY transcription factors and proteins encoded by the genes from the "PEN" pathway required for penetration resistance to filamentous pathogens). Thus, this work provides an inventory of candidate phosphoproteins, including putative direct MAPK substrates, for future analysis of MAPK-mediated defense control. (Proteomics data are available with the identifier PXD001252 via ProteomeXchange, http://proteomecentral.proteomexchange.org).

  5. Influence of dietary carbohydrate on zinc-deficiency-induced changes in oxidative defense mechanisms and tissue oxidative damage in rats.

    PubMed

    Kim, S H; Keen, C L

    1999-10-01

    The aim of this study was to determine the effect of dietary carbohydrate type on the expression of zinc (Zn) deficiency in rats with respect to tissue oxidative damage and defense mechanisms. Rats were fed diets containing adequate (+Zn) or low concentrations (-Zn) of Zn. Both fructose- and glucose-based diets were tested. Pair-fed controls were also studied to evaluate changes in the oxidative defense system which are secondary to Zn-deficiency-induced anorexia. Plasma and liver Zn concentrations and CuZn superoxide dismutase activities were lower in the -Zn rats than in the +Zn rats. Liver glutathione (GSH) and disulfide glutathione concentrations were higher in the -Zn rats than in the +Zn rats; this difference was most pronounced in the fructose groups. Liver and heart selenium glutathione peroxidase (Se-GSH-Px) activities were lower in the -Zn-fructose group than in the +Zn-fructose group. Liver Se-GSH-Px activity was higher in the fructose groups than in the glucose groups. Liver GSH reductase (GSH-Red) activity was lower in the -Zn-fructose group than in its control group. Liver glutamine synthetase activity was lower in the -Zn-glucose group and in the fructose groups than in the glucose control group. Liver thiobarbituric acid reactive substance (TBARS) production was similar among the groups. Collectively, these results support the concept that Zn deficiency can result in an impaired oxidant defense system. Based on the observation that pair-fed control animals also showed evidence of oxidative damage, we suggest that one factor that contributes to the effect of Zn deficiency is the reduction in caloric intake that occurs in these animals. Fructose feeding resulted in increased activities of several of the oxidant defense enzymes. Protein oxidative damage assessed by glutamine synthetase activity was increased by both Zn deficiency and fructose feeding.

  6. Strong down-regulation of glycophorin genes: A host defense mechanism against rotavirus infection.

    PubMed

    Salas, Antonio; Marco-Puche, Guillermo; Triviño, Juan Carlos; Gómez-Carballa, Alberto; Cebey-López, Miriam; Rivero-Calle, Irene; Vilanova-Trillo, Lucía; Rodríguez-Tenreiro, Carmen; Gómez-Rial, José; Martinón-Torres, Federico

    2016-10-01

    The mechanisms of rotavirus (RV) infection have been analyzed from different angles but the way in which RV modifies the transcriptome of the host is still unknown. Whole transcriptome shotgun sequencing of peripheral blood samples was used to reveal patterns of expression from the genome of RV-infected patients. RV provokes global changes in the transcriptome of infected cells, involving an over-expression of genes involved in cell cycle and chromatin condensation. While interferon IFI27 was hyper-activated, interferon type II was not suggesting that RV has developed mechanisms to evade the innate response by host cells after virus infection. Most interesting was the inhibition of genes of the glycophorins A and B (GYPA/B) family, which are the major sialoglycoproteins of the human erythrocyte membrane and receptor of several viruses for host invasion. RV infection induces a complex and global response in the host. The strong inhibition of glycophorins suggests a novel defense mechanism of the host to prevent viral infection, inhibiting the expression of receptors used by the virus for infection. The present results add further support to the systemic nature of RV infection.

  7. Defense mechanisms after brief cognitive-behavior group therapy for panic disorder: one-year follow-up.

    PubMed

    Heldt, Elizeth; Blaya, Carolina; Kipper, Leticia; Salum, Giovanni A; Otto, Michael W; Manfro, Gisele G

    2007-06-01

    Changes in defense mechanisms have been shown in long-term psychodynamic treatment. The aim of this study was to examine the changes that occurred after brief cognitive-behavior group therapy in the defense style of panic disorder patients that had failed to respond to pharmacotherapy. Forty-seven patients participated in the study and severity of panic disorder was evaluated by Clinical Global Impression. Defense mechanisms were evaluated by the Defense Style Questionnaire. Patients decreased the use of maladaptive defenses after cognitive-behavior group therapy, and the change in immature defenses was maintained at 1-year follow-up evaluation (p = 0.022). These modifications were associated with reduction of symptoms (F = 0.359; p = 0.047). These findings are consistent with the hypothesis that defense styles are malleable in short-term treatment and are, at least partially, symptom-state dependent.

  8. DNA Damage Response and Immune Defense: Links and Mechanisms

    PubMed Central

    Nakad, Rania; Schumacher, Björn

    2016-01-01

    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 signaling 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 signaling. We highlight evidence gained into (i) which molecular and cellular pathways of DDR activate immune signaling, (ii) how DNA damage drives chronic inflammation, and (iii) how chronic inflammation causes DNA damage and pathology in humans. PMID:27555866

  9. Psychogenic non-epileptic seizures: so-called psychiatric comorbidity and underlying defense mechanisms

    PubMed Central

    Beghi, Massimiliano; Negrini, Paola Beffa; Perin, Cecilia; Peroni, Federica; Magaudda, Adriana; Cerri, Cesare; Cornaggia, Cesare Maria

    2015-01-01

    In Diagnostic and Statistical Manual of Mental Disorders, fifth edition, psychogenic non-epileptic seizures (PNES) do not have a unique classification as they can be found within different categories: conversion, dissociative, and somatization disorders. The ICD-10, instead, considers PNES within dissociative disorders, merging the dissociative disorders and conversion disorders, although the underlying defense mechanisms are different. The literature data show that PNES are associated with cluster B (mainly borderline) personality disorders and/or to people with depressive or anxiety disorders. Defense mechanisms in patients with PNES with a prevalence of anxious/depressive symptoms are of “neurotic” type; their goal is to lead to a “split”, either vertical (dissociation) or horizontal (repression). The majority of patients with this type of PNES have alexithymia traits, meaning that they had difficulties in feeling or perceiving emotions. In subjects where PNES are associated with a borderline personality, in which the symbolic function is lost, the defense mechanisms are of a more archaic nature (denial). PNES with different underlying defense mechanisms have different prognoses (despite similar severity of PNES) and need usually a different treatment (pharmacological or psychological). Thus, it appears superfluous to talk about psychiatric comorbidity, since PNES are a different symptomatic expression of specific psychiatric disorders. PMID:26491330

  10. Brief Report: The Defense Mechanisms of Homophobic Adolescent Males--A Descriptive Discriminant Analysis

    ERIC Educational Resources Information Center

    Lewis, Andrew J.; White, Jennifer

    2009-01-01

    The study examined the role of defense mechanisms in homophobic attitudes of older male adolescents aged 17-18 years. A cross-sectional survey collected data from final year high school students (N = 86) attending an all male school in a regional centre in Victoria, Australia. The school was identified by teachers as having a problematic culture…

  11. Learning to Recognize Ego Defense Mechanisms: Results of a Structured Teaching Experience for Psychiatric Residents

    ERIC Educational Resources Information Center

    Beresford, Thomas P.

    2005-01-01

    Objective: Ego defense mechanism (EDM) recognition can offer a powerful and practical tool in clinical psychiatry. However, recognition skill learning can be difficult to assess and may account for the lack of formal EDM recognition training in residency courses. Method: This study hypothesized that mean test scores would increase significantly…

  12. Effects of Sex, Social Desirability, and Birth Order on the Defense Mechanisms Inventory.

    ERIC Educational Resources Information Center

    Dudley, Gary E.

    1978-01-01

    Investigated effects of sex difference, social desirability instructions, and birth order of respondents on defense mechanisms inventory (DMI). Sex difference was found in projection only. Social desirability effects were found in turning-against-others, projection, principalization, and reversal. Thus, an interpretive caution is in order…

  13. DNA DAMAGE REPAIR AND CELL CYCLE CONTROL: A NATURAL BIO-DEFENSE MECHANISM

    EPA Science Inventory

    DNA DAMAGE REPAIR AND CELL CYCLE CONTROL: A natural bio-defense mechanism
    Anuradha Mudipalli.

    Maintenance of genetic information, including the correct sequence of nucleotides in DNA, is essential for replication, gene expression, and protein synthesis. DNA lesions onto...

  14. A Systems Biology Approach to the Coordination of Defensive and Offensive Molecular Mechanisms in the Innate and Adaptive Host-Pathogen Interaction Networks.

    PubMed

    Wu, Chia-Chou; Chen, Bor-Sen

    2016-01-01

    Infected zebrafish coordinates defensive and offensive molecular mechanisms in response to Candida albicans infections, and invasive C. albicans coordinates corresponding molecular mechanisms to interact with the host. However, knowledge of the ensuing infection-activated signaling networks in both host and pathogen and their interspecific crosstalk during the innate and adaptive phases of the infection processes remains incomplete. In the present study, dynamic network modeling, protein interaction databases, and dual transcriptome data from zebrafish and C. albicans during infection were used to infer infection-activated host-pathogen dynamic interaction networks. The consideration of host-pathogen dynamic interaction systems as innate and adaptive loops and subsequent comparisons of inferred innate and adaptive networks indicated previously unrecognized crosstalk between known pathways and suggested roles of immunological memory in the coordination of host defensive and offensive molecular mechanisms to achieve specific and powerful defense against pathogens. Moreover, pathogens enhance intraspecific crosstalk and abrogate host apoptosis to accommodate enhanced host defense mechanisms during the adaptive phase. Accordingly, links between physiological phenomena and changes in the coordination of defensive and offensive molecular mechanisms highlight the importance of host-pathogen molecular interaction networks, and consequent inferences of the host-pathogen relationship could be translated into biomedical applications.

  15. Mechanisms and Modifications of Naturally Occurring Host Defense Peptides for Anti-HIV Microbicide Development

    PubMed Central

    Eade, Colleen R.; Wood, Matthew P.; Cole, Alexander M.

    2014-01-01

    Despite advances in the treatment of HIV infection, heterosexual transmission of HIV remains high, and vaccines to prevent HIV acquisition have been unfruitful. Vaginal microbicides, on the other hand, have demonstrated considerable potential for HIV prevention, and a variety of compounds have been screened for their activity and safety as anti-HIV microbicides. Among these are the naturally occurring host defense peptides, small peptides from diverse lineages with intrinsic antiviral activity. Naturally occurring host defense peptides with anti-HIV activity are promising candidates for vaginal microbicide development. Their structural variance and accompanying mechanistic diversity provide a wide range of inhibitors whose antiviral activity can be exerted at nearly every stage of the HIV lifecycle. Additionally, peptide modification has been explored as a method for improving the anti-HIV activity of host defense peptides. Structure- and sequence-based alterations have achieved varying success in improving the potency and specificity of anti-HIV peptides. Overall, peptides have been discovered or engineered to inhibit HIV with therapeutic indices of >1000, encouraging their advancement toward clinical trials. Here we review the naturally occurring anti-HIV host defense peptides, demonstrating their breadth of mechanistic diversity, and exploring approaches to enhance and optimize their activity in order to expedite their development as safe and effective anti-HIV vaginal microbicides. PMID:22264047

  16. Antimicrobial peptides: modes of mechanism, modulation of defense responses.

    PubMed

    Rahnamaeian, Mohammad

    2011-09-01

    Complicated schemes of classical breeding and their drawbacks, environmental risks imposed by agrochemicals, decrease of arable land, and coincident escalating damages of pests and pathogens have accentuated the necessity for highly efficient measures to improve crop protection. During co-evolution of host-microbe interactions, antimicrobial peptides (AMPs) have exhibited a brilliant history in protecting host organisms against devastation by invading pathogens. Since the 1980s, a plethora of AMPs has been isolated from and characterized in different organisms. Nevertheless the AMPs expressed in plants render them more resistant to diverse pathogens, a more orchestrated approach based on knowledge of their mechanisms of action and cellular targets, structural toxic principle, and possible impact on immune system of corresponding transgenic plants will considerably improve crop protection strategies against harmful plant diseases. This review outlines the current knowledge on different modes of action of AMPs and then argues the waves of AMPs’ ectopic expression on transgenic plants’ immune system.

  17. Lico A Enhances Nrf2-Mediated Defense Mechanisms against t-BHP-Induced Oxidative Stress and Cell Death via Akt and ERK Activation in RAW 264.7 Cells

    PubMed Central

    Lv, Hongming; Ren, Hua; Wang, Lidong; Chen, Wei; Ci, Xinxin

    2015-01-01

    Licochalcone A (Lico A) exhibits various biological properties, including anti-inflammatory and antioxidant activities. In this study, we investigated the antioxidative potential and mechanisms of Lico A against tert-butyl hydroperoxide- (t-BHP-) induced oxidative damage in RAW 264.7 cells. Our results indicated that Lico A significantly inhibited t-BHP-induced cytotoxicity, apoptosis, and reactive oxygen species (ROS) generation and reduced glutathione (GSH) depletion but increased the glutamate-cysteine ligase modifier (GCLM) subunit and the glutamate-cysteine ligase catalytic (GCLC) subunit genes expression. Additionally, Lico A dramatically upregulated the antioxidant enzyme heme oxygenase 1 (HO-1) and nuclear factor erythroid 2-related factor 2 (Nrf2), which were associated with inducing Nrf2 nuclear translocation, decreasing Keap1 protein expression and increasing antioxidant response element (ARE) promoter activity. Lico A also obviously induced the activation of serine/threonine kinase (Akt) and extracellular signal-regulated kinase (ERK), but PI3K/Akt and ERK inhibitors treatment displayed clearly decreased levels of LicoA-induced Nrf2 nuclear translocation and HO-1 expression, respectively. Furthermore, Lico A treatment markedly attenuated t-BHP-induced oxidative damage, which was reduced by treatment with PI3K/Akt, ERK, and HO-1 inhibitors. Therefore, Lico A might have a protective role against t-BHP-induced cytotoxicity by modulating HO-1 and by scavenging ROS via the activation of the PI3K/Akt and ERK/Nrf2 signaling pathways. PMID:26576227

  18. Lico A Enhances Nrf2-Mediated Defense Mechanisms against t-BHP-Induced Oxidative Stress and Cell Death via Akt and ERK Activation in RAW 264.7 Cells.

    PubMed

    Lv, Hongming; Ren, Hua; Wang, Lidong; Chen, Wei; Ci, Xinxin

    2015-01-01

    Licochalcone A (Lico A) exhibits various biological properties, including anti-inflammatory and antioxidant activities. In this study, we investigated the antioxidative potential and mechanisms of Lico A against tert-butyl hydroperoxide- (t-BHP-) induced oxidative damage in RAW 264.7 cells. Our results indicated that Lico A significantly inhibited t-BHP-induced cytotoxicity, apoptosis, and reactive oxygen species (ROS) generation and reduced glutathione (GSH) depletion but increased the glutamate-cysteine ligase modifier (GCLM) subunit and the glutamate-cysteine ligase catalytic (GCLC) subunit genes expression. Additionally, Lico A dramatically upregulated the antioxidant enzyme heme oxygenase 1 (HO-1) and nuclear factor erythroid 2-related factor 2 (Nrf2), which were associated with inducing Nrf2 nuclear translocation, decreasing Keap1 protein expression and increasing antioxidant response element (ARE) promoter activity. Lico A also obviously induced the activation of serine/threonine kinase (Akt) and extracellular signal-regulated kinase (ERK), but PI3K/Akt and ERK inhibitors treatment displayed clearly decreased levels of LicoA-induced Nrf2 nuclear translocation and HO-1 expression, respectively. Furthermore, Lico A treatment markedly attenuated t-BHP-induced oxidative damage, which was reduced by treatment with PI3K/Akt, ERK, and HO-1 inhibitors. Therefore, Lico A might have a protective role against t-BHP-induced cytotoxicity by modulating HO-1 and by scavenging ROS via the activation of the PI3K/Akt and ERK/Nrf2 signaling pathways.

  19. Mycobacteria counteract a TLR-mediated nitrosative defense mechanism in a zebrafish infection model.

    PubMed

    Elks, Philip M; van der Vaart, Michiel; van Hensbergen, Vincent; Schutz, Esther; Redd, Michael J; Murayama, Emi; Spaink, Herman P; Meijer, Annemarie H

    2014-01-01

    Pulmonary tuberculosis (TB), caused by the intracellular bacterial pathogen Mycobacterium tuberculosis (Mtb), is a major world health problem. The production of reactive nitrogen species (RNS) is a potent cytostatic and cytotoxic defense mechanism against intracellular pathogens. Nevertheless, the protective role of RNS during Mtb infection remains controversial. Here we use an anti-nitrotyrosine antibody as a readout to study nitration output by the zebrafish host during early mycobacterial pathogenesis. We found that recognition of Mycobacterium marinum, a close relative of Mtb, was sufficient to induce a nitrosative defense mechanism in a manner dependent on MyD88, the central adaptor protein in Toll like receptor (TLR) mediated pathogen recognition. However, this host response was attenuated by mycobacteria via a virulence mechanism independent of the well-characterized RD1 virulence locus. Our results indicate a mechanism of pathogenic mycobacteria to circumvent host defense in vivo. Shifting the balance of host-pathogen interactions in favor of the host by targeting this virulence mechanism may help to alleviate the problem of infection with Mtb strains that are resistant to multiple drug treatments.

  20. Temporal and Spatial Resolution of Activated Plant Defense Responses in Leaves of Nicotiana benthamiana Infected with Dickeya dadantii

    PubMed Central

    Pérez-Bueno, María L.; Granum, Espen; Pineda, Mónica; Flors, Víctor; Rodriguez-Palenzuela, Pablo; López-Solanilla, Emilia; Barón, Matilde

    2016-01-01

    The necrotrophic bacteria Dickeya dadantii is the causal agent of soft-rot disease in a broad range of hosts. The model plant Nicotiana benthamiana, commonly used as experimental host for a very broad range of plant pathogens, is susceptible to infection by D. dadantii. The inoculation with D. dadantii at high dose seems to overcome the plant defense capacity, inducing maceration and death of the tissue, although restricted to the infiltrated area. By contrast, the output of the defense response to low dose inoculation is inhibition of maceration and limitation in the growth, or even eradication, of bacteria. Responses of tissue invaded by bacteria (neighboring the infiltrated areas after 2–3 days post-inoculation) included: (i) inhibition of photosynthesis in terms of photosystem II efficiency; (ii) activation of energy dissipation as non-photochemical quenching in photosystem II, which is related to the activation of plant defense mechanisms; and (iii) accumulation of secondary metabolites in cell walls of the epidermis (lignins) and the apoplast of the mesophyll (phytoalexins). Infiltrated tissues showed an increase in the content of the main hormones regulating stress responses, including abscisic acid, jasmonic acid, and salicylic acid. We propose a mechanism involving the three hormones by which N. benthamiana could activate an efficient defense response against D. dadantii. PMID:26779238

  1. Exploring the association of ego defense mechanisms with problematic internet use in a Pakistani medical school.

    PubMed

    Waqas, Ahmed; Rehman, Abdul; Malik, Aamenah; Aftab, Ramsha; Allah Yar, Aroosa; Allah Yar, Arooj; Rai, Aitzaz Bin Sultan

    2016-09-30

    The present study was designed to analyze association between problematic internet use and use of ego defense mechanisms in medical students. This cross-sectional study was undertaken at CMH Lahore Medical College (CMH LMC) in Lahore, Pakistan from 1st March, 2015 to 30th May, 2015. 522 medical and dental students were included in the study. The questionnaire consisted of three sections: a) demographic characteristics of respondent b) the Defense Style Questionnaire-40 (DSQ-40) and c) the Internet Addiction Test (IAT). All data were analyzed in SPSS v20. Chi square, Independent sample t test and One Way ANOVA were run to analyze association of different variables with scores on IAT. Multiple regression analysis was used to delineate ego defenses as predictors of problematic internet use. A total of 32 (6.1%) students reported severe problems with internet usage. Males had higher scores on IAT i.e had more problematic use of internet. Scores on internet addiction test (IAT) were negatively associated with sublimation and positively associated with projection, denial, autistic fantasy, passive aggression and displacement. There was a high prevalence of problematic use of internet among medical and dental students. It had significant associations with several defense mechanisms.

  2. Assessment of safety of lactobacillus strains based on resistance to host innate defense mechanisms.

    PubMed

    Asahara, Takashi; Takahashi, Masatoshi; Nomoto, Koji; Takayama, Hiroo; Onoue, Masaharu; Morotomi, Masami; Tanaka, Ryuichiro; Yokokura, Teruo; Yamashita, Naoya

    2003-01-01

    Seven Lactobacillus strains belonging to four species were evaluated for pathogenicity as well as for in vitro sensitivity to the bactericidal mechanisms of macrophages in a rabbit infective endocarditis (IE) model. Two bacteremia-associated strains, L. rhamnosus PHLS A103/70 and L. casei PHLS A357/84, as well as the L. rhamnosus type strain and the probiotic L. rhamnosus strain ATCC 53103, showed moderate infectivity, and the virulence of the probiotic L. casei strain Shirota and type strains such as L. acidophilus ATCC 4356(T) and L. gasseri DSM 20243(T) in the model was negligible. The strains that showed pathogenic potential in the rabbit IE model (PHLS A357/84, PHLS A103/70, and ATCC 53103) were more resistant than strain Shirota to intracellular killing activity by mouse macrophages in vitro and also to bactericidal nitrogen intermediates, such as nitric oxide and NO(2)(-) ions. These results suggest that resistance to host innate defense systems, which would function at inflammatory lesions, should be considered in the safety assessment of Lactobacillus strains.

  3. Department of Defense In-House RDT&E Activities

    DTIC Science & Technology

    1986-10-30

    Research Management, Air Force IResearch, Army Research . Navy Researche Research 19 ABSTRACT (Continue on reverse if necessary and identify by block...Aeromedical Research Laboratory ........................ 1 Air Defense Artillery Board ............................ 2 Airborne & Special Operations...NAVY Aerospace Medical Research Laboratory .................. 55 Air Development Center ................................. 56 Air Propulsion

  4. UVR defense mechanisms in eurytopic and invasive Gracilaria vermiculophylla (Gracilariales, Rhodophyta).

    PubMed

    Roleda, Michael Y; Nyberg, Cecilia D; Wulff, Angela

    2012-10-01

    The invasive success of Gracilaria vermiculophylla has been attributed to its wide tolerance range to different abiotic factors, but its response to ultraviolet radiation (UVR) is yet to be investigated. In the laboratory, carpospores and vegetative thalli of an Atlantic population were exposed to different radiation treatments consisting of high PAR (photosynthetically active radiation) only (P), PAR+UV-A (PA) and PAR+UV-A+UV-B (PAB). Photosynthesis of carpospores was photoinhibited under different radiation treatments but photosystem II (PSII) function was restored after 12 h under dim white light. Growth of vegetative thalli was significantly higher under radiation supplemented with UVR. Decrease in chlorophyll a (Chl a) under daily continuous 16-h exposure to 300 µmol photons m(-2) s(-1) of PAR suggests preventive accumulation of excited chlorophyll molecules within the antennae to minimize the generation of dangerous reactive oxygen species. Moreover, an increase in total carotenoids and xanthophyll cycle pigments (i.e. violaxanthin, antheraxanthin and zeaxanthin) further suggests effective photoprotection under UVR. The presence of the ketocarotenoid β-cryptoxanthin also indicates protection against UVR and oxidative stress. The initial concentration of total mycosporine-like amino acids (MAAs) in freshly-released spores increased approximately four times after 8-h laboratory radiation treatments. On the other hand, initial specific MAAs in vegetative thalli changed in composition after 7-day exposure to laboratory radiation conditions without affecting the total concentration. The above responses suggest that G. vermiculophylla have multiple UVR defense mechanisms to cope with the dynamic variation in light quantity and quality encountered in its habitat. Beside being eurytopic, the UVR photoprotective mechanisms likely contribute to the current invasive success of the species in shallow lagoons and estuaries exposed to high solar radiation.

  5. Defense mechanisms of Pseudomonas aeruginosa PAO1 against quantum dots and their released heavy metals.

    PubMed

    Yang, Yu; Mathieu, Jacques M; Chattopadhyay, Soma; Miller, Jeffrey T; Wu, Tianpin; Shibata, Tomohiro; Guo, Wenhua; Alvarez, Pedro J J

    2012-07-24

    The growing use of quantum dots (QDs) in numerous applications increases the possibility of their release to the environment. Bacteria provide critical ecosystem services, and understanding their response to QDs is important to assess the potential environmental impacts of such releases. Here, we analyze the microbial response to sublethal exposure to commercial QDs, and investigate potential defense and adaptation mechanisms in the model bacterium Pseudomonas aeruginosa PAO1. Both intact and weathered QDs, as well as dissolved metal constituents, up-regulated czcABC metal efflux transporters. Weathered QDs also induced superoxide dismutase gene sodM, which likely served as a defense against oxidative stress. Interestingly, QDs also induced antibiotic resistance (ABR) genes and increased antibiotic minimum inhibitory concentrations by 50 to 100%, which suggests up-regulation of global stress defense mechanisms. Extracellular synthesis of nanoparticles (NPs) was observed after exposure to dissolved Cd(NO(3))(2) and SeO(2). With extended X-ray absorption fine structure (EXAFS), we discerned biogenic NPs such as CdO, CdS, CdSe, and selenium sulfides. These results show that bacteria can mitigate QD toxicity by turning on energy-dependent heavy-metal ion efflux systems and by mediating the precipitation of dissolved metal ions as less toxic and less bioavailable insoluble NPs.

  6. Investigating Aggressive Styles and Defense Mechanisms in Bipolar Patients and in their Parents.

    PubMed

    Bragazzi, Nicola Luigi; Pezzoni, Franca; Del Puente, Giovanni

    2014-11-06

    Bipolar disorder (BD) is a very common mental health disorder, whose etiology concerning aggressive styles and defense mechanisms is still poorly known despite the efforts dedicated to develop psychological and biological theories. After obtaining written signed informed consent, this study will recruit inpatients with a clinical diagnosis of BD, based on Structured Clinical Interview and the Diagnostic and Statistical Manual of Mental Disorders criteria, and their parents. The Bus-Perry Aggression Questionnaire, the Defense Style Questionnaire 40, the Symptom check list SCL-90-R, developed by DeRogatis will be administered to the participants, together with a semi-structured questionnaire concerning demographic data (age, gender, employment, education) and only for the patients clinical information (onset year of the disorder, presence of co-morbidities, alcohol and drug use, suicide tendencies, kind of treatment). All the questionnaires are in the Italian validated version. The successful completion of this study will shed light on the relationship between aggressive styles and defensive mechanisms in bipolar inpatients and in their parents, helping the clinicians to develop ad hoc psychological interventions.

  7. Priming by rhizobacterium protects tomato plants from biotrophic and necrotrophic pathogen infections through multiple defense mechanisms.

    PubMed

    Ahn, Il-Pyung; Lee, Sang-Woo; Kim, Min Gab; Park, Sang-Ryeol; Hwang, Duk-Ju; Bae, Shin-Chul

    2011-07-01

    A selected strain of rhizobacterium, Pseudomonas putida strain LSW17S (LSW17S), protects tomato plants (Lycopersicon esculentum L. cv. Seokwang) from bacterial speck by biotrophic Pseudomonas syringae pv. tomato strain DC3000 (DC3000) and bacterial wilt by necrotrophic Ralstonia solanacearum KACC 10703 (Rs10703). To investigate defense mechanisms induced by LSW17S in tomato plants, transcription patterns of pathogenesis-related (PR) genes and H(2)O(2) production were analyzed in plants treated with LSW17S and subsequent pathogen inoculation. LSW17S alone did not induce transcriptions of employed PR genes in leaves and roots. DC3000 challenge following LSW17S triggered rapid transcriptions of PR genes and H(2)O(2) production in leaves and roots. Catalase infiltration with DC3000 attenuated defense-related responses and resistance against DC3000 infection. Despite depriving H(2)O(2) production and PR1b transcription by the same treatment, resistance against Rs10703 infection was not deterred significantly. H(2)O(2) is indispensable for defense signaling and/or mechanisms primed by LSW17S and inhibition of bacterial speck, however, it is not involved in resistance against bacterial wilt.

  8. Impaired enzymatic defensive activity, mitochondrial dysfunction and proteasome activation are involved in RTT cell oxidative damage.

    PubMed

    Cervellati, Carlo; Sticozzi, Claudia; Romani, Arianna; Belmonte, Giuseppe; De Rasmo, Domenico; Signorile, Anna; Cervellati, Franco; Milanese, Chiara; Mastroberardino, Pier Giorgio; Pecorelli, Alessandra; Savelli, Vinno; Forman, Henry J; Hayek, Joussef; Valacchi, Giuseppe

    2015-10-01

    A strong correlation between oxidative stress (OS) and Rett syndrome (RTT), a rare neurodevelopmental disorder affecting females in the 95% of the cases, has been well documented although the source of OS and the effect of a redox imbalance in this pathology has not been yet investigated. Using freshly isolated skin fibroblasts from RTT patients and healthy subjects, we have demonstrated in RTT cells high levels of H2O2 and HNE protein adducts. These findings correlated with the constitutive activation of NADPH-oxidase (NOX) and that was prevented by a NOX inhibitor and iron chelator pre-treatment, showing its direct involvement. In parallel, we demonstrated an increase in mitochondrial oxidant production, altered mitochondrial biogenesis and impaired proteasome activity in RTT samples. Further, we found that the key cellular defensive enzymes: glutathione peroxidase, superoxide dismutase and thioredoxin reductases activities were also significantly lower in RTT. Taken all together, our findings suggest that the systemic OS levels in RTT can be a consequence of both: increased endogenous oxidants as well as altered mitochondrial biogenesis with a decreased activity of defensive enzymes that leads to posttranslational oxidant protein modification and a proteasome activity impairment.

  9. Mechanism of bystander-blaming: defensive attribution, counterfactual thinking, and gender.

    PubMed

    Levy, Inna; Ben-David, Sarah

    2015-01-01

    Contemporary victimology recognizes that an understanding of the mechanism of blaming requires a comprehensive approach that includes the victim, the offender, and the bystander. However, most of the existing research on blaming focuses on the victim and the offender, ignoring the issue of bystander-blaming. This study highlights the bystander and investigates bystander-blaming by exploring some theoretical explanations, including counterfactual thinking, defensive attribution, and gender differences. The study included 363 young male and female participants, who read vignettes describing the behavior of the victim and the bystander in a rape scenario and answered questions regarding bystander-blaming. The results show that both counterfactual thinking and defensive attribution play a role in bystander-blaming. This article addresses the theoretical and practical implications of these findings.

  10. Molecular Dynamics Simulation and Statistics Analysis Reveals the Defense Response Mechanism in Plants

    NASA Astrophysics Data System (ADS)

    Liu, Zhichao; Zhao, Yunjie; Zeng, Chen; Computational Biophysics Lab Team

    As the main protein of the bacterial flagella, flagellin plays an important role in perception and defense response. The newly discovered locus, FLS2, is ubiquitously expressed. FLS2 encodes a putative receptor kinase and shares many homologies with some plant resistance genes and even with some components of immune system of mammals and insects. In Arabidopsis, FLS2 perception is achieved by the recognition of epitope flg22, which induces FLS2 heteromerization with BAK1 and finally the plant immunity. Here we use both analytical methods such as Direct Coupling Analysis (DCA) and Molecular Dynamics (MD) Simulations to get a better understanding of the defense mechanism of FLS2. This may facilitate a redesign of flg22 or de-novo design for desired specificity and potency to extend the immune properties of FLS2 to other important crops and vegetables.

  11. Viral myocarditis: potential defense mechanisms within the cardiomyocyte against virus infection

    PubMed Central

    Yajima, Toshitaka

    2011-01-01

    Virus infection can inflict significant damage on cardiomyocytes through direct injury and secondary immune reactions, leading to myocarditis and dilated cardiomyopathy. While viral myocarditis or cardiomyopathy is a complication of systemic infection of cardiotropic viruses, most individuals infected with the viruses do not develop significant cardiac disease. However, some individuals proceed to develop severe virus-mediated heart disease. Recent studies have shown that viral infection of cardiomyocytes is required for the development of myocarditis and subsequent cardiomyopathy. This suggests that viral infection of cardiomyocytes can be an important step that determines the pathogenesis of viral myocarditis during systemic infection. Accordingly, this article focuses on potential defense mechanisms within the cardiomyocyte against virus infection. Understanding of the cardiomyocyte defense against invading viruses may give us novel insights into the pathophysiology of viral myocarditis, and enable us to develop innovative strategies of diagnosis and treatment for this challenging clinical entity. PMID:21585262

  12. Essential Functional Modules for Pathogenic and Defensive Mechanisms in Candida albicans Infections

    PubMed Central

    Tsai, I-Chun; Lin, Che; Chuang, Yung-Jen

    2014-01-01

    The clinical and biological significance of the study of fungal pathogen Candida albicans (C. albicans) has markedly increased. However, the explicit pathogenic and invasive mechanisms of such host-pathogen interactions have not yet been fully elucidated. Therefore, the essential functional modules involved in C. albicans-zebrafish interactions were investigated in this study. Adopting a systems biology approach, the early-stage and late-stage protein-protein interaction (PPI) networks for both C. albicans and zebrafish were constructed. By comparing PPI networks at the early and late stages of the infection process, several critical functional modules were identified in both pathogenic and defensive mechanisms. Functional modules in C. albicans, like those involved in hyphal morphogenesis, ion and small molecule transport, protein secretion, and shifts in carbon utilization, were seen to play important roles in pathogen invasion and damage caused to host cells. Moreover, the functional modules in zebrafish, such as those involved in immune response, apoptosis mechanisms, ion transport, protein secretion, and hemostasis-related processes, were found to be significant as defensive mechanisms during C. albicans infection. The essential functional modules thus determined could provide insights into the molecular mechanisms of host-pathogen interactions during the infection process and thereby devise potential therapeutic strategies to treat C. albicans infection. PMID:24757665

  13. Molecular Mechanisms of Anthracycline Activity

    NASA Astrophysics Data System (ADS)

    Beretta, Giovanni Luca; Zunino, Franco

    On the basis of evidence that anthracyclines are DNA intercalating agents and DNA is the primary target, a large number of analogs and related intercalators have been developed. However, doxorubicin and closely related anthracyclines still remain among the most effective antitumor agents. Multiple mechanisms have been proposed to explain their efficacy. They include inhibition of DNA-dependent functions, free radical formation, and membrane interactions. The primary mechanism of action is now ascribed to drug interference with the function of DNA topoisomerase II. The stabilization of the topoisomerase-mediated cleavable complex results in a specific type of DNA damage (i.e., double-strand protein-associated DNA breaks). The drug-stabilized cleavable complex is a potentially reversible molecular event and its persistence, as a consequence of strong DNA binding, may be recognized as an apoptotic stimulus. Indirect evidence supports the notion that the bioreductive processes of the quinone moiety generating the semiquinone radical with concomitant production of reactive oxygen species may contribute to the drug effects. The cellular defense mechanisms and response to genotoxic/cytotoxic stress appear to be critical determinants of the tumor sensitivity to anthracyclines.

  14. Jasmonic acid and salicylic acid activate a common defense system in rice

    PubMed Central

    Tamaoki, Daisuke; Seo, Shigemi; Yamada, Shoko; Kano, Akihito; Miyamoto, Ayumi; Shishido, Hodaka; Miyoshi, Seika; Taniguchi, Shiduku; Akimitsu, Kazuya; Gomi, Kenji

    2013-01-01

    Jasmonic acid (JA) and salicylic acid (SA) play important roles in plant defense systems. JA and SA signaling pathways interact antagonistically in dicotyledonous plants, but, the status of crosstalk between JA and SA signaling is unknown in monocots. Our rice microarray analysis showed that more than half of the genes upregulated by the SA analog BTH are also upregulated by JA, suggesting that a major portion of the SA-upregulated genes are regulated by JA-dependent signaling in rice. A common defense system that is activated by both JA and SA is thus proposed which plays an important role in pathogen defense responses in rice. PMID:23518581

  15. Mechanically Active Electrospun Materials

    NASA Astrophysics Data System (ADS)

    Robertson, Jaimee M.

    Electrospinning, a technique used to fabricate small diameter polymer fibers, has been employed to develop unique, active materials falling under two categories: (1) shape memory elastomeric composites (SMECs) and (2) water responsive fiber mats. (1) Previous work has characterized in detail the properties and behavior of traditional SMECs with isotropic fibers embedded in an elastomer matrix. The current work has two goals: (i) characterize laminated anisotropic SMECs and (ii) develop a fabrication process that is scalable for commercial SMEC manufacturing. The former ((i)) requires electrospinning aligned polymer fibers. The aligned fibers are similarly embedded in an elastomer matrix and stacked at various fiber orientations. The resulting laminated composite has a unique response to tensile deformation: after stretching and releasing, the composite curls. This curling response was characterized based on fiber orientation. The latter goal ((ii)) required use of a dual-electrospinning process to simultaneously electrospin two polymers. This fabrication approach incorporated only industrially relevant processing techniques, enabling the possibility of commercial application of a shape memory rubber. Furthermore, the approach had the added benefit of increased control over composition and material properties. (2) The strong elongational forces experienced by polymer chains during the electrospinning process induce molecular alignment along the length of electrospun fibers. Such orientation is maintained in the fibers as the polymer vitrifies. Consequently, residual stress is stored in electrospun fiber mats and can be recovered by heating through the polymer's glass transition temperature. Alternatively, the glass transition temperature can be depressed by introducing a plasticizing agent. Poly(vinyl acetate) (PVAc) is plasticized by water, and its glass transition temperature is lowered below room temperature. Therefore, the residual stress can be relaxed at room

  16. Modulatory effects of deltamethrin on antioxidant defense mechanisms and lipid peroxidation in Carassius auratus gibelio liver and intestine.

    PubMed

    Dinu, Diana; Marinescu, Diana; Munteanu, Maria Cristina; Staicu, Andreea Cristina; Costache, Marieta; Dinischiotu, Anca

    2010-04-01

    Pyrethroids, such as deltamethrin, are toxic substances that lead to generation of reactive oxygen species, which harm living organisms. We assessed the level and patterns of imbalance evolved by a single dose of 2 microg/L deltamethrin on the lipid peroxidation (LPO) and the antioxidant defense system of Carassius auratus gibelio liver and intestine, and monitored the recovery dynamics of these parameters during a 14-day post-exposure period. LPO and antioxidative defense mechanisms displayed different responses in the investigated tissues. Sudden increase of LPO in the liver, persisting at this elevated level throughout the test period, was observed on the third day post-exposure, while in the intestine significant enhancement of this parameter was recorded from the seventh day. Reduced glutathione (GSH) showed a transient increase in the liver, and was depleted in the intestine by the second day of exposure, with signs of recovery by the end of the experimental tenure. In the liver of fish a temporary inhibition of superoxide dismutase (SOD) and catalase (CAT) activity, and activation of glutathione peroxidase (GPX), glutathione transferase (GST), and glutathione reductase (GR) enzymes was observed, with maximum thresholds recorded on the third and second days, respectively. In the intestine a relevant increase in CAT and GST activity up to the second day and almost complete recovery by the end of the experiment was recorded, while for GR a continuous enhancement was apparent.

  17. Of Amoebae and Men: Extracellular DNA Traps as an Ancient Cell-Intrinsic Defense Mechanism

    PubMed Central

    Zhang, Xuezhi; Soldati, Thierry

    2016-01-01

    Since the discovery of the formation of DNA-based extracellular traps (ETs) by neutrophils as an innate immune defense mechanism (1), hundreds of articles describe the involvement of ETs in physiological and pathological human and animal conditions [reviewed in Ref. (2), and the previous Frontiers Research Topic on NETosis: http://www.frontiersin.org/books/NETosis_At_the_Intersection_of_Cell_Biology_Microbiology_and_Immunology/195]. Interestingly, a few reports reveal that ETs can be formed by immune cells of more ancient organisms, as far back as the common ancestor of vertebrates and invertebrates (3). Recently, we reported that the Sentinel cells of the multicellular slug of the social amoeba Dictyostelium discoideum also produce ETs to trap and kill slug-invading bacteria [see Box 1; and Figure 1 Ref. (4)]. This is a strong evidence that DNA-based cell-intrinsic defense mechanisms emerged much earlier than thought, about 1.3 billion years ago. Amazingly, using extrusion of DNA as a weapon to capture and kill uningestable microbes has its rationale. During the emergence of multicellularity, a primitive innate immune system developed in the form of a dedicated set of specialized phagocytic cells. This professionalization of immunity allowed the evolution of sophisticated defense mechanisms including the sacrifice of a small set of cells by a mechanism related to NETosis. This altruistic behavior likely emerged in steps, starting from the release of “dispensable” mitochondrial DNA by D. discoideum Sentinel cells. Grounded in this realization, one can anticipate that in the near future, many more examples of the invention and fine-tuning of ETs by early metazoan ancestors will be identified. Consequently, it can be expected that this more complete picture of the evolution of ETs will impact our views of the involvement and pathologies linked to ETs in human and animals. PMID:27458458

  18. Active auditory mechanics in mosquitoes.

    PubMed Central

    Göpfert, M. C.; Robert, D.

    2001-01-01

    In humans and other vertebrates, hearing is improved by active contractile properties of hair cells. Comparable active auditory mechanics is now demonstrated in insects. In mosquitoes, Johnston's organ transduces sound-induced vibrations of the antennal flagellum. A non-muscular 'motor' activity enhances the sensitivity and tuning of the flagellar mechanical response in physiologically intact animals. This motor is capable of driving the flagellum autonomously, amplifying sound-induced vibrations at specific frequencies and intensities. Motor-related electrical activity of Johnston's organ strongly suggests that mosquito hearing is improved by mechanoreceptor motility. PMID:11270428

  19. Stimulation of TLRs by LMW-HA induces self-defense mechanisms in vaginal epithelium.

    PubMed

    Dusio, Giuseppina F; Cardani, Diego; Zanobbio, Laura; Mantovani, Martina; Luchini, Patrizia; Battini, Lorenzo; Galli, Valentina; Diana, Angela; Balsari, Andrea; Rumio, Cristiano

    2011-07-01

    The innate immune system is present throughout the female reproductive tract and functions in synchrony with the adaptive immune system to provide protection in a way that enhances the chances for fetal survival, while protecting against potential pathogens. Recent data show that activation of Toll-like receptor (TLR)2 and 4 by low-molecular weight hyaluronic acid (LMW-HA) in the epidermis induces secretion of the antimicrobial peptide β-defensin 2. In the present work, we show that LMW-HA induces vaginal epithelial cells to release different antimicrobial peptides, via activation of TLR2 and TLR4. Further, we found that LMW-HA favors repair of vaginal epithelial injury, involving TLR2 and TLR4, and independently from its classical receptor CD44. This wound-healing activity of LMW-HA is dependent from an Akt/phosphatidylinositol 3 kinase pathway. Therefore, these findings suggest that the vaginal epithelium is more than a simple physical barrier to protect against invading pathogens: on the contrary, this surface acts as efficient player of innate host defense, which may modulate its antimicrobial properties and injury restitution activity, following LMW-HA stimulation; this activity may furnish an additional protective activity to this body compartment, highly and constantly exposed to microbiota, ameliorating the self-defense of the vaginal epithelium in both basal and pathological conditions.

  20. Antimicrobial terpenes from oleoresin of ponderosa pine tree Pinus ponderosa: A defense mechanism against microbial invasion

    SciTech Connect

    Himejima, Masaki; Hobson, K.R.; Otsuka, Toshikazu; Wood, D.L.; Kubo, Isao )

    1992-10-01

    The oleoresin of the ponderosa pine, Pinus ponderosa (Pinaceae) exhibited broad antimicrobial activity. In order to identify the active compounds, the oleoresin was steam distilled to give a distillate and residue. The distillate contained mainly monoterpenes and some sesquiterpenes, while the residue consisted chiefly of four structurally related diterpene acids. An antimicrobial assay with the pure compounds indicated that the monoterpenes were active primarily against fungi, but there was also some activity against gram-positive bacteria. The diterpene acids, in contrast, only exhibited activity against gram-positive bacteria. Although not all of the identified sesquiterpenes could be tested, longifolene showed activity only against gram-positive bacteria. Therefore, it appears that the oleoresin of P. ponderosa functions as a biochemical defense against microbial invasion.

  1. Enhanced antioxidant defense due to extracellular catalase activity in Syrian hamster during arousal from hibernation.

    PubMed

    Ohta, Hitomi; Okamoto, Iwao; Hanaya, Toshiharu; Arai, Shigeyuki; Ohta, Tsunetaka; Fukuda, Shigeharu

    2006-08-01

    Mammalian hibernators are considered a natural model for resistance to ischemia-reperfusion injuries, and protective mechanisms against oxidative stress evoked by repeated hibernation-arousal cycles in these animals are increasingly the focus of experimental investigation. Here we show that extracellular catalase activity provides protection against oxidative stress during arousal from hibernation in Syrian hamster. To examine the serum antioxidant defense system, we first assessed the hibernation-arousal state-dependent change in serum attenuation of cytotoxicity induced by hydrogen peroxide. Serum obtained from hamsters during arousal from hibernation at a rectal temperature of 32 degrees C, concomitant with the period of increased oxidative stress, attenuated the cytotoxicity four-fold more effectively than serum from cenothermic control hamsters. Serum catalase activity significantly increased during arousal, whereas glutathione peroxidase activity decreased by 50%, compared with cenothermic controls. The cytoprotective effect of purified catalase at the concentration found in serum was also confirmed in a hydrogen peroxide-induced cytotoxicity model. Moreover, inhibition of catalase by aminotriazole led to an 80% loss of serum hydrogen peroxide scavenging activity. These results suggest that extracellular catalase is effective for protecting hibernators from oxidative stress evoked by arousal from hibernation.

  2. Association of Ego Defense Mechanisms with Academic Performance, Anxiety and Depression in Medical Students: A Mixed Methods Study

    PubMed Central

    Waqas, Ahmed; Malik, Aamenah; Muhammad, Umer; Khan, Sarah; Mahmood, Nadia

    2015-01-01

    Background: Ego defense mechanisms are unconscious psychological processes that help an individual to prevent anxiety when exposed to a stressful situation. These mechanisms are important in psychiatric practice to assess an individual’s personality dynamics, psychopathologies, and modes of coping with stressful situations, and hence, to design appropriate individualized treatment. Our study delineates the relationship of ego defense mechanisms with anxiety, depression, and academic performance of Pakistani medical students. Methods: This cross-sectional study was done at CMH Lahore Medical College and Fatima Memorial Hospital Medical and Dental College, both in Lahore, Pakistan, from December 1, 2014 to January 15, 2015. Convenience sampling was used and only students who agreed to take part in this study were included. The questionnaire consisted of three sections: 1) Demographics, documenting demographic data and academic scores on participants’ most recent exams; 2) Hospital Anxiety and Depression Scale (HADS); and 3) Defense Style Questionnaire-40 (DSQ-40). The data were analyzed with SPSS v. 20. Mean scores and frequencies were calculated for demographic variables and ego defense mechanisms. Bivariate correlations, one-way ANOVA, and multiple linear regression were used to identify associations between academic scores, demographics, ego defense mechanisms, anxiety, and depression. Results: A total of 409 medical students participated, of whom 286 (70%) were females and 123 (30%) were males. Mean percentage score on the most recent exams was 75.6% in medical students. Bivariate correlation revealed a direct association between mature and neurotic ego defense mechanisms and academic performance, and an indirect association between immature mechanisms and academic performance. One-way ANOVA showed that moderate levels of anxiety (P < .05) and low levels of depression (P < .05) were associated with higher academic performance. Conclusion: There was a

  3. Surveillance-activated defenses block the ROS-induced mitochondrial unfolded protein response.

    PubMed

    Runkel, Eva D; Liu, Shu; Baumeister, Ralf; Schulze, Ekkehard

    2013-01-01

    Disturbance of cellular functions results in the activation of stress-signaling pathways that aim at restoring homeostasis. We performed a genome-wide screen to identify components of the signal transduction of the mitochondrial unfolded protein response (UPR(mt)) to a nuclear chaperone promoter. We used the ROS generating complex I inhibitor paraquat to induce the UPR(mt), and we employed RNAi exposure post-embryonically to allow testing genes whose knockdown results in embryonic lethality. We identified 54 novel regulators of the ROS-induced UPR(mt). Activation of the UPR(mt), but not of other stress-signaling pathways, failed when homeostasis of basic cellular mechanisms such as translation and protein transport were impaired. These mechanisms are monitored by a recently discovered surveillance system that interprets interruption of these processes as pathogen attack and depends on signaling through the JNK-like MAP-kinase KGB-1. Mutation of kgb-1 abrogated the inhibition of ROS-induced UPR(mt), suggesting that surveillance-activated defenses specifically inhibit the UPR(mt) but do not compromise activation of the heat shock response, the UPR of the endoplasmic reticulum, or the SKN-1/Nrf2 mediated response to cytosolic stress. In addition, we identified PIFK-1, the orthologue of the Drosophila PI 4-kinase four wheel drive (FWD), and found that it is the only known factor so far that is essential for the unfolded protein responses of both mitochondria and endoplasmic reticulum. This suggests that both UPRs may share a common membrane associated mechanism.

  4. Growth, photosynthesis, and defense mechanism of antimony (Sb)-contaminated Boehmeria nivea L.

    PubMed

    Chai, Li-Yuan; Mubarak, Hussani; Yang, Zhi-Hui; Yong, Wang; Tang, Chong-Jian; Mirza, Nosheen

    2016-04-01

    Ramie (Boehmeria nivea L.) is the oldest cash fiber crop in China and is widely grown in antimony (Sb) mining areas. To evaluate the extent of Sb resistance and tolerance, the growth, tolerance index (TI), Sb content in plant parts and in Hoagland solution, bioaccumulation factor (BF), photosynthesis, and physiological changes in Sb-contaminated B. nivea (20, 40, 80, and 200 mg L(-1) Sb) grown hydroponically were investigated. The Sb tolerance and resistance of ramie were clearly revealed by growth inhibition, a TI between 13 and 99 %, non-significant changes in the maximum quantum efficiency of photosystem (F v /F m ), energy-harvesting efficiency (photosystem II (PSII)) and single-photon avalanche diode (SPAD) value, a significant increase in Sb in plant parts, BF >1, and an increase in catalase (CAT) and malondialdehyde (MDA) at 200 mg L(-1) Sb. Under increasing Sb stress, nearly the same non-significant decline in the maximum quantum efficiency of photosystem (F v /F m ), energy-harvesting efficiency (PSII), relative quantum yield of photosystem II (φPSII), and photochemical quenching (qP), except for F v /F m at 20 mg L(-1) Sb, were recorded. SPAD values for chlorophyll under Sb stress showed an increasing trend, except for a slight decrease, i.e., <2 %, than the control SPAD value at 200 mg L(-1) Sb. With a continuous increase in MDA, superoxide dismutase (SOD), peroxidase (POD), and CAT activities were suppressed under Sb addition up to 40 mg L(-1) Sb and the addition of Sb enhanced enzyme production at 80 and 200 mg L(-1) Sb. A continuous decrease in SOD, POD, and CAT up to 40 mg L(-1) Sb and enhancements at ≥80 mg L(-1), along with the continuous enhancement of MDA activity and inhibited biomass production, clearly reveal the roles of these enzymes in detoxifying Sb stress and the defense mechanism of ramie at 80 mg L(-1) Sb. Thus, B. nivea constitutes a promising candidate for Sb phytoremediation at mining sites.

  5. Contrasting Potato Foliage and Tuber Defense Mechanisms against the Late Blight Pathogen Phytophthora infestans

    PubMed Central

    Bradeen, James M.

    2016-01-01

    The late blight pathogen Phytophthora infestans can attack both potato foliage and tubers. When inoculated with P. infestans, foliage of nontransformed ‘Russet Burbank’ (WT) develops late blight disease while that of transgenic ‘Russet Burbank’ line SP2211 (+RB) does not. We compared the foliar transcriptome responses of these two lines to P. infestans inoculation using an RNA-seq approach. A total of 515 million paired end RNA-seq reads were generated, representing the transcription of 29,970 genes. We also compared the differences and similarities of defense mechanisms against P. infestans in potato foliage and tubers. Differentially expressed genes, gene groups and ontology bins were identified to show similarities and differences in foliage and tuber defense mechanisms. Our results suggest that R gene dosage and shared biochemical pathways (such as ethylene and stress bins) contribute to RB-mediated incompatible potato-P. infestans interactions in both the foliage and tubers. Certain ontology bins such as cell wall and lipid metabolisms are potentially organ-specific. PMID:27441721

  6. Neuroinflammatory contributions to pain after SCI: roles for central glial mechanisms and nociceptor-mediated host defense.

    PubMed

    Walters, Edgar T

    2014-08-01

    Neuropathic pain after spinal cord injury (SCI) is common, often intractable, and can be severely debilitating. A number of mechanisms have been proposed for this pain, which are discussed briefly, along with methods for revealing SCI pain in animal models, such as the recently applied conditioned place preference test. During the last decade, studies of animal models have shown that both central neuroinflammation and behavioral hypersensitivity (indirect reflex measures of pain) persist chronically after SCI. Interventions that reduce neuroinflammation have been found to ameliorate pain-related behavior, such as treatment with agents that inhibit the activation states of microglia and/or astroglia (including IL-10, minocycline, etanercept, propentofylline, ibudilast, licofelone, SP600125, carbenoxolone). Reversal of pain-related behavior has also been shown with disruption by an inhibitor (CR8) and/or genetic deletion of cell cycle-related proteins, deletion of a truncated receptor (trkB.T1) for brain-derived neurotrophic factor (BDNF), or reduction by antisense knockdown or an inhibitor (AMG9810) of the activity of channels (TRPV1 or Nav1.8) important for electrical activity in primary nociceptors. Nociceptor activity is known to drive central neuroinflammation in peripheral injury models, and nociceptors appear to be an integral component of host defense. Thus, emerging results suggest that spinal and systemic effects of SCI can activate nociceptor-mediated host defense responses that interact via neuroinflammatory signaling with complex central consequences of SCI to drive chronic pain. This broader view of SCI-induced neuroinflammation suggests new targets, and additional complications, for efforts to develop effective treatments for neuropathic SCI pain.

  7. Dysfunctionality of the xylem in Olea europaea L. Plants associated with the infection process by Verticillium dahliae Kleb. Role of phenolic compounds in plant defense mechanism.

    PubMed

    Báidez, Ana G; Gómez, Pedro; Del Río, José A; Ortuño, Ana

    2007-05-02

    Xylem ultrastructural modification and the possible participation of phenolic compounds in the natural defense or resistance mechanisms of olive plants infected with Verticillium dahliae Kleb. were studied. Microscopic study showed that the mycelium propagated and passed from one element to another through the pit. The formation of tyloses and aggregates contributed to obstruction of the xylem lumen. In vivo changes in the levels of these phenolic compounds in infected olive plants and their antifungal activity against Verticillium dahliae Kleb., as revealed by in vitro study, strongly suggest that they are involved in natural defense or resistance mechanisms in this plant material, the most active being quercetin and luteolin aglycons, followed by rutin, oleuropein, luteolin-7-glucoside, tyrosol, p-coumaric acid, and catechin. .

  8. Hepcidin-induced hypoferremia is a critical host defense mechanism against the siderophilic bacterium Vibrio vulnificus.

    PubMed

    Arezes, João; Jung, Grace; Gabayan, Victoria; Valore, Erika; Ruchala, Piotr; Gulig, Paul A; Ganz, Tomas; Nemeth, Elizabeta; Bulut, Yonca

    2015-01-14

    Hereditary hemochromatosis, an iron overload disease caused by a deficiency in the iron-regulatory hormone hepcidin, is associated with lethal infections by siderophilic bacteria. To elucidate the mechanisms of this susceptibility, we infected wild-type and hepcidin-deficient mice with the siderophilic bacterium Vibrio vulnificus and found that hepcidin deficiency results in increased bacteremia and decreased survival of infected mice, which can be partially ameliorated by dietary iron depletion. Additionally, timely administration of hepcidin agonists to hepcidin-deficient mice induces hypoferremia that decreases bacterial loads and rescues these mice from death, regardless of initial iron levels. Studies of Vibrio vulnificus growth ex vivo show that high iron sera from hepcidin-deficient mice support extraordinarily rapid bacterial growth and that this is inhibited in hypoferremic sera. Our findings demonstrate that hepcidin-mediated hypoferremia is a host defense mechanism against siderophilic pathogens and suggest that hepcidin agonists may improve infection outcomes in patients with hereditary hemochromatosis or thalassemia.

  9. Proteomic investigation of the effect of salicylic acid on Arabidopsis seed germination and establishment of early defense mechanisms.

    PubMed

    Rajjou, Loïc; Belghazi, Maya; Huguet, Romain; Robin, Caroline; Moreau, Adrien; Job, Claudette; Job, Dominique

    2006-07-01

    The influence of salicylic acid (SA) on elicitation of defense mechanisms in Arabidopsis (Arabidopsis thaliana) seeds and seedlings was assessed by physiological measurements combined with global expression profiling (proteomics). Parallel experiments were carried out using the NahG transgenic plants expressing the bacterial gene encoding SA hydroxylase, which cannot accumulate the active form of this plant defense elicitor. SA markedly improved germination under salt stress. Proteomic analyses disclosed a specific accumulation of protein spots regulated by SA as inferred by silver-nitrate staining of two-dimensional gels, detection of carbonylated (oxidized) proteins, and neosynthesized proteins with [35S]-methionine. The combined results revealed several processes potentially affected by SA. This molecule enhanced the reinduction of the late maturation program during early stages of germination, thereby allowing the germinating seeds to reinforce their capacity to mount adaptive responses in environmental water stress. Other processes affected by SA concerned the quality of protein translation, the priming of seed metabolism, the synthesis of antioxidant enzymes, and the mobilization of seed storage proteins. All the observed effects are likely to improve seed vigor. Another aspect revealed by this study concerned the oxidative stress entailed by SA in germinating seeds, as inferred from a characterization of the carbonylated (oxidized) proteome. Finally, the proteomic data revealed a close interplay between abscisic signaling and SA elicitation of seed vigor.

  10. Repeated exposures to roadside particulate matter extracts suppresses pulmonary defense mechanisms, resulting in lipid and protein oxidative damage.

    PubMed

    Pardo, Michal; Porat, Ziv; Rudich, Assaf; Schauer, James J; Rudich, Yinon

    2016-03-01

    Exposure to particulate matter (PM) pollution in cities and urban canyons can be harmful to the exposed population. However, the underlying mechanisms that lead to health effects are not yet elucidated. It is postulated that exposure to repeated, small, environmentally relevant concentrations can affect lung homeostasis. This study examines the impact of repeated exposures to urban PM on mouse lungs with focus on inflammatory and oxidative stress parameters. Aqueous extracts from collected urban PM were administered to mice by 5 repeated intra-tracheal instillations (IT). Multiple exposures, led to an increase in cytokine levels in both bronchoalveolar lavage fluid and in the blood serum, indicating a systemic reaction. Lung mRNA levels of antioxidant/phase II detoxifying enzymes decreased by exposure to the PM extract, but not when metals were removed by chelation. Finally, disruption of lung tissue oxidant-inflammatory/defense balance was evidenced by increased levels of lipid and protein oxidation. Unlike response to a single IT exposure to the same dose and source of extract, multiple exposures result in lung oxidative damage and a systemic inflammatory reaction. These could be attributed to compromised capacity to activate the protective Nrf2 tissue defense system. It is suggested that water-soluble metals present in urban PM, potentially from break and tire wear, may constitute major drivers of the pulmonary and systemic responses to multiple exposure to urban PM.

  11. Anatomy and function of the ptychoid defensive mechanism in the mite Euphthiracarus cooki (Acari: Oribatida).

    PubMed

    Sanders, Francis H; Norton, Roy A

    2004-02-01

    Ptychoidy is a defensive adaptation of several groups of oribatid mites in which legs and coxisternum can be fully retracted into the opisthosoma and protected by a ventrally deflected prodorsum, resulting in a seed-like appearance. Using Euphthiracarus cooki as a model, we examined details of exoskeletal and muscular anatomy in combination with studies of live individuals to provide the first functional analysis of ptychoidy. There are two main functional components: the first is a set of exoskeletal and muscular adaptations, mostly of the podosoma and prodorsum, that combine to effect leg withdrawal and prodorsal deflection; the second comprises adaptations of the opisthosoma that allow control of hydrostatic pressure during the large hemocoel volume adjustments associated with ptychoidy. Adaptations important in the closing process (enptychosis) are found in four body regions. Much of the podosomal exoskeleton (especially pleural) is unsclerotized, which facilitates leg retraction and prodorsal deflection during enptychosis. The coxisternum has several flexible furrows along which it folds in order to bring legs into a tightly parallel arrangement. The prodorsum has specialized attachment surfaces (manubrium and inferior retractor process) for retractor muscles and a paired bothridial scale that participates in prodorsal alignment during enptychosis. The subcapitulum has a prominent capitular apodeme on which important retractor muscles insert. The mineralized notogaster has an anterior "collar" that accommodates the retracted prodorsum; it includes paired notches and receptacles that accommodate the bothridial scales, thereby creating a temporary fixed axis for rotation of the prodorsum in a "lazy hinge" mechanism. Specialized muscles form the retractor system; most conspicuous are the large coxisternal retractors and prodorsal retractors, both of which originate on the notogaster. Other components have adjustor roles; among them are muscles of the endosternal

  12. Analysis of Active Sensor Discrimination Requirements for Various Defense Missile Defense Scenarios Final Report 1999(99-ERD-080)

    SciTech Connect

    Ledebuhr, A.G.; Ng, L.C.; Gaughan, R.J.

    2000-02-15

    During FY99, we have explored and analyzed a combined passive/active sensor concept to support the advanced discrimination requirements for various missile defense scenario. The idea is to combine multiple IR spectral channels with an imaging LIDAR (Light Detection and Ranging) behind a common optical system. The imaging LIDAR would itself consist of at least two channels; one at the fundamental laser wavelength (e.g., the 1.064 {micro}m for Nd:YAG) and one channel at the frequency doubled (at 532 nm for Nd:YAG). two-color laser output would, for example, allow the longer wavelength for a direct detection time of flight ranger and an active imaging channel at the shorter wavelength. The LIDAR can function as a high-resolution 2D spatial image either passively or actively with laser illumination. Advances in laser design also offer three color (frequency tripled) systems, high rep-rate operation, better pumping efficiencies that can provide longer distance acquisition, and ranging for enhanced discrimination phenomenology. New detector developments can enhance the performance and operation of both LIDAR channels. A real time data fusion approach that combines multi-spectral IR phenomenology with LIDAR imagery can improve both discrimination and aim-point selection capability.

  13. Whisking mechanics and active sensing.

    PubMed

    Bush, Nicholas E; Solla, Sara A; Hartmann, Mitra Jz

    2016-10-01

    We describe recent advances in quantifying the three-dimensional (3D) geometry and mechanics of whisking. Careful delineation of relevant 3D reference frames reveals important geometric and mechanical distinctions between the localization problem ('where' is an object) and the feature extraction problem ('what' is an object). Head-centered and resting-whisker reference frames lend themselves to quantifying temporal and kinematic cues used for object localization. The whisking-centered reference frame lends itself to quantifying the contact mechanics likely associated with feature extraction. We offer the 'windowed sampling' hypothesis for active sensing: that rats can estimate an object's spatial features by integrating mechanical information across whiskers during brief (25-60ms) windows of 'haptic enclosure' with the whiskers, a motion that resembles a hand grasp.

  14. Preventive role of lens antioxidant defense mechanism against riboflavin-mediated sunlight damaging of lens crystallins.

    PubMed

    Anbaraki, Afrooz; Khoshaman, Kazem; Ghasemi, Younes; Yousefi, Reza

    2016-10-01

    The main components of sunlight reaching the eye lens are UVA and visible light exerting their photo-damaging effects indirectly by the aid of endogenous photosensitizer molecules such as riboflavin (RF). In this study, lens proteins solutions were incubated with RF and exposed to the sunlight. Then, gel mobility shift analysis and different spectroscopic assessments were applied to examine the structural damaging effects of solar radiation on these proteins. Exposure of lens proteins to direct sunlight, in the presence of RF, leads to marked structural crosslinking, oligomerization and proteolytic instability. These structural damages were also accompanied with reduction in the emission fluorescence of Trp and Tyr and appearance of a new absorption peak between 300 and 400nm which can be related to formation of new chromophores. Also, photo-oxidation of lens crystallins increases their oligomeric size distribution as examined by dynamic light scattering analysis. The above mentioned structural insults, as potential sources of sunlight-induced senile cataract and blindness, were significantly attenuated in the presence of ascorbic acid and glutathione which are two important components of lens antioxidant defense system. Therefore, the powerful antioxidant defense mechanism of eye lens is an important barrier against molecular photo-damaging effects of solar radiations during the life span.

  15. Monuments of memory: defensive mechanisms of the collective psyche and their manifestation in the memorialization process.

    PubMed

    Kalinowska, Malgorzata

    2012-09-01

    The paper searches for insight in the area of collective memory as a part of collective consciousness, a phenomenon understood as a stabilizing factor for a society's self-image and identity. Collective memories are seen as originating from shared communications transmitting and creating the meaning of the past in the form of narrative, symbols and signs. As such, they contain the individual, embodied and lived side of our relations to the past. As well as the identity-building and meaning-making functions of collective memories, their defensive function is discussed with a focus on commemorative practices taking place in a transitional space between psychic and social life. Fears of a lack of collective identity and coherence have contributed to the way Polish commemorative practices have been shaped. This is considered in relation to the Smolensk catastrophe in 2010, viewed in the context of the Jungian concept of the collective psyche and the psychoanalytical understanding of defensive group mechanisms against trauma, especially those relating to loss and mourning. It leads to a consideration of how historical experiences and the experience of history can be accessed, as well as their meaning for individual and group development.

  16. Department of Defense In-House RDT&E Activities. Management Analysis Report

    DTIC Science & Technology

    1988-10-30

    Defense . . . . . . 35 Medical Research Institute of Infectious Diseases . . . . . 36 Missile Research, Development a Engineering Center . . . . 37 Natick...FACTORS CAPABILITIES AVAILABLE. COMPUTER SUPPORT AVAILABLE. TEMPERATURES TO -50 DEG FAHR COMMON. 18 INSTALLATION: COMBAT SYSTEMS TEST ACTIVITY ABERDEEN...RESUSCITATION METHODS FOR USE IN FORWARD AREAS; DERMAL PROTECTION FROM CHEM AGENTS AND VECTOR BORNE DISEASE ; R&D TESTING IN TOXICOLOGY; FORWARD AREA

  17. Fiscal Year 1985 Congressional budget request. Volume 1. Atomic energy defense activities

    SciTech Connect

    Not Available

    1984-02-01

    Contents include: summaries of estimates by appropriation, savings from management initiatives, staffing by subcommittee, staffing appropriation; appropriation language; amounts available for obligation; estimates by major category; program overview; weapons activities; verification and control technology; materials production; defense waste and by-products management; nuclear safeguards and security; security investigations; and naval reactors development.

  18. [Medical accidents and defense activities against criminal investigation--the attorney's point of view].

    PubMed

    Goto, Sadato

    2012-09-01

    Even after the criminal investigation has begun on a medical accident, immediate defense activities can prevent false indictment. On appointing a lawyer, one has to be careful of "conflicts of interests". Defense lawyers try to reconstruct what happened on the scene with the records and the comments of the persons involved. Meanwhile, they try to nail down the medical standards in the particular case by scrutinizing medical bibliography. If they succeed in pointing out to the authorities the possibilities of not guilty verdict, arrest or indictment can be avoided.

  19. Comparison of pulmonary defense mechanisms in Rocky Mountain bighorn (Ovis canadensis canadensis) and domestic sheep.

    PubMed

    Silflow, R M; Foreyt, W J; Taylor, S M; Laegreid, W W; Liggitt, H D; Leid, R W

    1989-10-01

    Alveolar macrophages were obtained from Rocky Mountain bighorn sheep (Ovis canadensis canadensis) and domestic sheep for the purpose of comparing pulmonary host defense mechanisms in the two species. Specific variables studied included (1) characterization of the cell types present in the lung, (2) alveolar macrophage phagocytic and bactericidal functions, (3) measurement of protein levels in lavage fluid, and (4) measurement of cortisol levels in lavage fluid. While phagocytic cell populations were similar between bighorn and domestic sheep, a significantly higher percentage of lymphocytes were present in bighorns than domestics (20% in bighorn versus 6% in domestic sheep). Significant differences were not observed in the phagocytic or bactericidal functions of macrophages between the two species. Significant differences were not observed in either lavage fluid protein levels or in cortisol levels.

  20. Roles of small RNAs in the immune defense mechanisms of crustaceans.

    PubMed

    He, Yaodong; Ju, Chenyu; Zhang, Xiaobo

    2015-12-01

    Small RNAs, 21-24 nucleotides in length, are non-coding RNAs found in most multicellular organisms, as well as in some viruses. There are three main types of small RNAs including microRNA (miRNA), small-interfering RNA (siRNA), and piwi-interacting RNA (piRNA). Small RNAs play key roles in the genetic regulation of eukaryotes; at least 50% of all eukaryote genes are the targets of small RNAs. In recent years, studies have shown that some unique small RNAs are involved in the immune response of crustaceans, leading to lower or higher immune responses to infections and diseases. SiRNAs could be used as therapy for virus infection. In this review, we provide an overview of the diverse roles of small RNAs in the immune defense mechanisms of crustaceans.

  1. Autonomic characteristics of defensive hostility: reactivity and recovery to active and passive stressors.

    PubMed

    Vella, Elizabeth J; Friedman, Bruce H

    2007-11-01

    The autonomic characteristics of hostility and defensiveness were assessed in 55 male undergraduates based on composite Cook Medley Hostility (Chost) and Marlowe Crowne Social Desirability (MC) scores to create 4 groups: Defensive Hostile (DH; high MC, high Chost), High Hostile (HH; low MC, high Chost), Defensive (Def; high MC, low Chost) and Low Hostile (LH; low MC, low Chost). All subjects engaged in a video game (VG) and hand cold pressor (CP) task. Cardiovascular responses in DH subjects were predicted to show enhanced sympathetic alpha and beta-adrenergic activity and the least vagal control compared to others across tasks. DH and LH men showed significant heart rate reactivity to the CP task compared to HH men. LH men showed significant reductions in high frequency power (vagal assessment) to the tasks compared to HH men. Future studies may employ harassment techniques and include the factors of gender and ethnicity in their assessments.

  2. New mechanism of lenalidomide activity.

    PubMed

    Keevan, Jacob; Figg, William D

    2014-08-01

    Lenalidomide is an immunomodulatory agent (IMiD) that has activity in hematologic cancer (e.g., multiple myeloma). The immunomodulatory and apoptotic properties are readily apparent in therapy. However, the exact mechanism of action has been difficult to quantify until recently when it was shown that another IMiD, thalidomide, binds to an E3 ubiquitin ligase complex constituent, CRBN. The article by Kronke et al. demonstrates that, by binding to CRBN and altering its selectivity, lenalidomide potentiates the ubiquitination and proteolysis of 2 specific proteins, IKZF1 and IKZF3. An article in the same issue, by Lu et al., supports these observations. IKZF1 and IKZF3 are transcription factors that are necessary for multiple myeloma, and repression of these transcription factors is a likely mechanism for lenalidomide activity in this disease.

  3. Geodetic activities of the Department of Defense under IGY programs

    SciTech Connect

    Williams, O.W.; Daugherty, K.I.

    1983-10-16

    Attention is given to the U.S. Department of Defence (DOD) activities that contributed to the International Geophysical Year's active, passive, and cooperative satellite programs. The DOD continues to support the deployment, enhancement, and application of novel technology in such areas as satellite altimetry, gravity radiometry, inertial surveying, interferometry, airborne gravimetry, inertial surveying, and CCD and laser methods for geodetic astronomy. Also noted are such major department initiatives as the Global Positioning System, which will become operational toward the end of this decade.

  4. Department of Defense In-House RDT&E Activities

    DTIC Science & Technology

    1983-10-30

    FUELS AND LUBRICATION, AND AIRCRAFT FIRE PROTECTION TECHNOLOGY. CONDUCT CONTRACT AND IN- HOUSE PRO- GRAMS, PROVIDE OPERATIONAL AND SYSTEM SUPPORT...FACILITIES INCLUDE IN- HOUSE LABORATORIES SPACE SIMULATION CHAMBERS, ROCKET AND BALLOON LAUNCH" FACILITIES, ND n"O KC-135 AIRCRAFT FOR OPTICAL, UPPER...1530 Statistician 1360 Oceanography 1540 Cryptography 1550 Computer Sciences Military professionals, both officer and enlisted, actively engaged in RDTE

  5. Drought resistance in rice seedlings conferred by seed priming : role of the anti-oxidant defense mechanisms.

    PubMed

    Goswami, Alakananda; Banerjee, Rahul; Raha, Sanghamitra

    2013-10-01

    Seed priming is a method by which seeds are subjected to different stress conditions to impart stress adaptation in seedlings germinating and growing under stressful situations. Drought stress is a major reason behind failure of crops. We studied the effects of hydropriming, dehydration priming (induced by PEG), and osmopriming (induced by NaCl and KH(2)PO(4)) on subsequent germination, growth and anti-oxidant defense mechanisms of 2-week-old rice seedlings under continuing dehydration stress. Unprimed seeds grown in PEG showed significantly lower germination and growth along with significantly higher reactive oxygen species (ROS) and lipid peroxidation levels. Among the priming methods, 5 % PEG priming was found to be the best in terms of germination and growth rate along with the lowest amount of ROS and lipid peroxidation (malondialdehyde [MDA]) values. MDA levels were reduced significantly by all of the priming methods. Hence, reduction of lipid peroxidation may be a key factor underlying the drought tolerance produced by the priming treatments. Glutathione peroxidase (GPX) activity seemed to bear an excellent correlation with oxidative stress resistance through seed priming. The PEG priming produced minimum peroxidative damage and superior germination and growth rate along with efficient GPX activity, overexpressed MnSOD and maintenance of HSP70 expression in normal as well as in drought condition. Therefore, in PEG-primed seeds the existence of robust protective mechanisms is definitely indicated.

  6. Antiviral activity and increased host defense against influenza infection elicited by the human cathelicidin LL-37.

    PubMed

    Barlow, Peter G; Svoboda, Pavel; Mackellar, Annie; Nash, Anthony A; York, Ian A; Pohl, Jan; Davidson, Donald J; Donis, Ruben O

    2011-01-01

    The extensive world-wide morbidity and mortality caused by influenza A viruses highlights the need for new insights into the host immune response and novel treatment approaches. Cationic Host Defense Peptides (CHDP, also known as antimicrobial peptides), which include cathelicidins and defensins, are key components of the innate immune system that are upregulated during infection and inflammation. Cathelicidins have immunomodulatory and anti-viral effects, but their impact on influenza virus infection has not been previously assessed. We therefore evaluated the effect of cathelicidin peptides on disease caused by influenza A virus in mice. The human cathelicidin, LL-37, and the murine cathelicidin, mCRAMP, demonstrated significant anti-viral activity in vivo, reducing disease severity and viral replication in infected mice to a similar extent as the well-characterized influenza virus-specific antiviral drug zanamivir. In vitro and in vivo experiments suggested that the peptides may act directly on the influenza virion rather than via receptor-based mechanisms. Influenza virus-infected mice treated with LL-37 had lower concentrations of pro-inflammatory cytokines in the lung than did infected animals that had not been treated with cathelicidin peptides. These data suggest that treatment of influenza-infected individuals with cathelicidin-derived therapeutics, or modulation of endogenous cathelicidin production may provide significant protection against disease.

  7. Defense mechanisms of sargassacean species against the epiphytic red alga Neosiphonia harveyi.

    PubMed

    Nakajima, Noboru; Ohki, Kaori; Kamiya, Mitsunobu

    2015-08-01

    Flora diversity and abundance of epiphytes are specific to their basiphyte species and may relate to variations in the defensive abilities of basiphytes. Thus, investigating the interactions between epiphytes and basiphytes is useful for a better understanding of the biological impact of epiphytism and the survival strategies of basiphytes. We examined the epiphyte density on five sargassacean species at six locations between two study sites, which showed that the epiphytic red alga Neosiphonia harveyi was remarkably less abundant on Sargassum siliquastrum at all locations. To assess its defense mechanism against N. harveyi, we performed bioassays of phlorotannins, which are considered effective in deterring fouling, by culturing sargassacean blades with N. harveyi carpospores and observed the process by which sargassacean blades remove epiphytes. When the carpospores were incubated with various concentrations of dissolved phlorotannins, settlement and germination were inhibited only at the highest concentrations (>0.1 g · L(-1) ), and this effect did not significantly differ among the five sargassacean species. When the carpospores were combined with blades from the five species, many of the spores attached and germinated on every blade. Because N. harveyi penetrated rhizoids into basiphyte tissues, cuticle peeling observed in all five sargassacean species could not remove this epiphyte after germination. However, in S. siliquastrum, the blade tissues around the germlings became swollen and disintegrative, and were removed together with the germlings. The spores normally grew on the dead blades, suggesting that the tissue degradation of S. siliquastrum is triggered by the infection of N. harveyi.

  8. Chromosome-level genome map provides insights into diverse defense mechanisms in the medicinal fungus Ganoderma sinense

    PubMed Central

    Zhu, Yingjie; Xu, Jiang; Sun, Chao; Zhou, Shiguo; Xu, Haibin; Nelson, David R.; Qian, Jun; Song, Jingyuan; Luo, Hongmei; Xiang, Li; Li, Ying; Xu, Zhichao; Ji, Aijia; Wang, Lizhi; Lu, Shanfa; Hayward, Alice; Sun, Wei; Li, Xiwen; Schwartz, David C.; Wang, Yitao; Chen, Shilin

    2015-01-01

    Fungi have evolved powerful genomic and chemical defense systems to protect themselves against genetic destabilization and other organisms. However, the precise molecular basis involved in fungal defense remain largely unknown in Basidiomycetes. Here the complete genome sequence, as well as DNA methylation patterns and small RNA transcriptomes, was analyzed to provide a holistic overview of secondary metabolism and defense processes in the model medicinal fungus, Ganoderma sinense. We reported the 48.96 Mb genome sequence of G. sinense, consisting of 12 chromosomes and encoding 15,688 genes. More than thirty gene clusters involved in the biosynthesis of secondary metabolites, as well as a large array of genes responsible for their transport and regulation were highlighted. In addition, components of genome defense mechanisms, namely repeat-induced point mutation (RIP), DNA methylation and small RNA-mediated gene silencing, were revealed in G. sinense. Systematic bioinformatic investigation of the genome and methylome suggested that RIP and DNA methylation combinatorially maintain G. sinense genome stability by inactivating invasive genetic material and transposable elements. The elucidation of the G. sinense genome and epigenome provides an unparalleled opportunity to advance our understanding of secondary metabolism and fungal defense mechanisms. PMID:26046933

  9. [Mechanisms of pathogenicity and host defense in infections by intracellular parasitic microbes].

    PubMed

    Mitsuyama, M; Suzuki, K

    2000-09-01

    Mycobacterium tuberculosis is one of the intracellular parasitic bacteria escaping the intracellular killing inside macrophages. The aim of this symposium was to get some insight into the mechanism of pathogenicity and host defense in M. tuberculosis infection, which has not yet been elucidated well, by the presentation of up-to-date knowledge on these aspect in infection with different intracellular parasitic microbes. Dr. Yoshikai (Nagoya Univ.) indicated that TLR is involved in the initial response of host against S. choleraesuis. Among the cytokines contributing to the induction of specific immunity, the importance of IL-15 was emphasized, based on their own experimental data using IL-15 transgenic mice and the application of anti-IL-15 antibody in vivo. Dr. Yoshida (Kyushu Univ.) reviewed the mechanisms of intracellular growth of Legionellae. Several genes so far identified as essential genes in intra-macrophage growth appeared to be similar to those encoding type 3 secretion system observed in Shigellae. There is a significant strain difference in the growth of L. pneumophila inside macrophages and such difference seemed to be under the control of a gene at chromosome 13, Lgn 1. The investigation of difference in the mode of escape among various Legionella. spp. may provide a novel mechansim in bacterial invasion and escape. Dr. Kawamura (Kyoto Univ.) summarized some new reports on the molecular mechanism of the inhibition of P-L fusion by M. tuberculosis. He emphasized the importance of the alteration in phagosomal maturation as indicated by the accumulation of TACO protein. The possible involvement of TLR in the recognition of Mycobacterial cells and its LAM was discussed. Dr. Kawakami (Ryukyu Univ.) first discussed the possibility that Cryptococcus neoformans, a fungal pathogen, could be regarded as one of the intracellular parasitic microbes. His presentation mainly focused on the TH1-Th2 balance in the expression of host defense against C. neoformans in

  10. Hepcidin-Induced Hypoferremia Is a Critical Host Defense Mechanism Against the Siderophilic Bacterium Vibrio vulnificus

    PubMed Central

    Arezes, João; Jung, Grace; Gabayan, Victoria; Valore, Erika; Ruchala, Piotr; Gulig, Paul A.; Ganz, Tomas; Nemeth, Elizabeta; Bulut, Yonca

    2014-01-01

    SUMMARY Hereditary hemochromatosis, an iron overload disease caused by a deficiency in the iron-regulatory hormone hepcidin, is associated with lethal infections by siderophilic bacteria. To elucidate the mechanisms of this susceptibility, we infected wild-type and hepcidin-deficient mice with the siderophilic bacterium Vibrio vulnificus, and found that hepcidin deficiency results in increased bacteremia and decreased survival of infected mice, which can be partially ameliorated by dietary iron depletion. Additionally, timely administration of hepcidin agonists to hepcidin-deficient mice induces hypoferremia that decreases bacterial loads and rescues these mice from death, regardless of initial iron levels. Studies of Vibrio vulnificus growth ex vivo show that high iron sera from hepcidin-deficient mice support extraordinarily rapid bacterial growth, and that this is inhibited in hypoferremic sera. Our findings demonstrate that hepcidin-mediated hypoferremia is a host defense mechanism against siderophilic pathogens and suggest that hepcidin agonists may improve infection outcomes in patients with hereditary hemochromatosis or thalassemia. PMID:25590758

  11. Microbial signature-triggered plant defense responses and early signaling mechanisms.

    PubMed

    Wu, Shujing; Shan, Libo; He, Ping

    2014-11-01

    It has long been observed that microbial elicitors can trigger various cellular responses in plants. Microbial elicitors have recently been referred to as pathogen or microbe-associated molecular patterns (PAMPs or MAMPs) and remarkable progress has been made on research of their corresponding receptors, signaling mechanisms and critical involvement in disease resistance. Plants also generate endogenous signals due to the damage or wounds caused by microbes. These signals were originally called endogenous elicitors and subsequently renamed damage-associated molecular patterns (DAMPs) that serve as warning signals for infections. The cellular responses induced by PAMPs and DAMPs include medium alkalinization, ion fluxes across the membrane, reactive oxygen species (ROS) and ethylene production. They collectively contribute to plant pattern-triggered immunity (PTI) and play an important role in plant basal defense against a broad spectrum of microbial infections. In this review, we provide an update on multiple PTI responses and early signaling mechanisms and discuss its potential applications to improve crop disease resistance.

  12. The AMPK-PPARGC1A pathway is required for antimicrobial host defense through activation of autophagy.

    PubMed

    Yang, Chul-Su; Kim, Jwa-Jin; Lee, Hye-Mi; Jin, Hyo Sun; Lee, Sang-Hee; Park, Ji-Hoon; Kim, Soung Jung; Kim, Jin-Man; Han, Yong-Mahn; Lee, Myung-Shik; Kweon, Gi Ryang; Shong, Minho; Jo, Eun-Kyeong

    2014-05-01

    AMP-activated protein kinase (AMPK) is a crucial energy sensor and plays a key role in integration of cellular functions to maintain homeostasis. Despite this, it is largely unknown whether targeting the AMPK pathway can be used as a therapeutic strategy for infectious diseases. Herein, we show that AMPK activation robustly induces antibacterial autophagy, which contributes to antimicrobial defense against Mycobacterium tuberculosis (Mtb). AMPK activation led to inhibition of Mtb-induced phosphorylation of the mechanistic target of rapamycin (MTOR) in macrophages. In addition, AMPK activation increased the genes involved in oxidative phosphorylation, mitochondrial ATP production, and biogenesis in Mtb-infected macrophages. Notably, peroxisome proliferator-activated receptor-gamma, coactivator 1α (PPARGC1A) was required for AMPK-mediated antimicrobial activity, as well as enhancement of mitochondrial function and biogenesis, in macrophages. Further, the AMPK-PPARGC1A pathway was involved in the upregulation of multiple autophagy-related genes via CCAAT/enhancer binding protein (C/EBP), β (CEBPB). PPARGC1A knockdown inhibited the AMPK-mediated induction of autophagy and impaired the fusion of phagosomes with MAP1LC3B (LC3B) autophagosomes in Mtb-infected macrophages. The link between autophagy, mitochondrial function, and antimicrobial activity was further demonstrated by studying LysMCre-mediated knockout of atg7, demonstrating mitochondrial ultrastructural defects and dysfunction, as well as blockade of antimicrobial activity against mycobacteria. Collectively, our results identify the AMPK-PPARGC1A axis as contributing to autophagy activation leading to an antimicrobial response, as a novel host defense mechanism.

  13. Intestinal autophagy activity is essential for host defense against Salmonella typhimurium infection in Caenorhabditis elegans.

    PubMed

    Curt, Alexander; Zhang, Jiuli; Minnerly, Justin; Jia, Kailiang

    2014-08-01

    Salmonella typhimurium infects both intestinal epithelial cells and macrophages. Autophagy is a lysosomal degradation pathway that is present in all eukaryotes. Autophagy has been reported to limit the Salmonella replication in Caenorhabditis elegans and in mammals. However, it is unknown whether intestinal autophagy activity plays a role in host defense against Salmonella infection in C. elegans. In this study, we inhibited the autophagy gene bec-1 in different C. elegans tissues and examined the survival of these animals following Salmonella infection. Here we show that inhibition of the bec-1 gene in the intestine but not in other tissues confers susceptibility to Salmonella infection, which is consistent with recent studies in mice showing that autophagy is involved in clearance of Salmonella in the intestinal epithelial cells. Therefore, the intestinal autophagy activity is essential for host defense against Salmonella infection from C. elegans to mice, perhaps also in humans.

  14. The Role of Defense Mechanisms, Personality and Demographical Factors on Complicated Grief following Death of a loved one by Cancer

    PubMed Central

    Rahimian Boogar, Isaac; Talepasand, Siavash

    2015-01-01

    Objective: Identification of the risk factors and psychological correlates of prolonged grief disorder is vital for health promotions in relatives of persons who died of cancer. The aim of this research was to investigate the role of defense mechanisms, character dimension of personality and demographic factors on complicated grief following a loss of a family member to cancer. Method: A number of 226 persons who had lost a family member to cancer in a cancer institute at Tehran University of Medical Science were selected through compliance sampling and completed the Inventory of complicated Grief-Revised (ICG-R), the Defense Styles Questionnaire (DSQ), the Character dimension of Temperament and Character Inventory (TCI), and the Demographical questionnaire. Data were analyzed by stepwise multiple regression analysis, using the PASW version 18. Results: Findings revealed that neurotic defense style had a significant positive predictive role in the complicated grief; and cooperativeness, age of the deceased person, self-transcendence and mature defense style had a significant negative predictive role in complicated grief (p<0.001). R2 was 0.73 for the final model (p<.001). Conclusion: The results revealed that two character dimensions (low cooperativeness and self-transcendence), high neurotic defense style and young age of the deceased person were involved in the psychopathological course of the complicated and prolonged grief. It was concluded that personality characteristics of the grieving persons and demographics of the deceased person should be addressed in designing tailored interventions for complicated grief. PMID:26884783

  15. The mtDNA NARP mutation activates the actin-Nrf2 signaling of antioxidant defenses

    SciTech Connect

    Dassa, Emmanuel Philippe; Paupe, Vincent; Goncalves, Sergio; Rustin, Pierre

    2008-04-11

    An efficient handling of superoxides by antioxidant defenses is a crucial issue for cells with respiratory chain deficient mitochondria. We used human cultured skin fibroblasts to delineate the mechanism controlling the expression of antioxidant defenses in the case of a severe ATPase deficiency resulting from an 8993T>G mutation in the mitochondrial ATPase6 gene. We observed the nuclear translocation of the transcription factor Nrf2 associated with thinning of the actin stress fibers. The mobilization of the Nrf2 signaling pathway could be mimicked by a chemical blockade of the ATPase with a specific inhibitor, oligomycin. Interestingly enough, Nrf2 nuclear translocation was not observed in the case of a severe cytochrome oxidase deficiency, indicating that studying the status of this signaling pathway could throw some light on the importance of the oxidative insult associated with different respiratory chain defects.

  16. Proteolytic Activation Transforms Heparin Cofactor II into a Host Defense Molecule

    PubMed Central

    Kalle, Martina; Papareddy, Praveen; Kasetty, Gopinath; Tollefsen, Douglas M.; Malmsten, Martin; Mörgelin, Matthias

    2013-01-01

    The abundant serine proteinase inhibitor heparin cofactor II (HCII) has been proposed to inhibit extravascular thrombin. However, the exact physiological role of this plasma protein remains enigmatic. In this study, we demonstrate a previously unknown role for HCII in host defense. Proteolytic cleavage of the molecule induced a conformational change, thereby inducing endotoxin-binding and antimicrobial properties. Analyses employing representative peptide epitopes mapped these effects to helices A and D. Mice deficient in HCII showed increased susceptibility to invasive infection by Pseudomonas aeruginosa, along with a significantly increased cytokine response. Correspondingly, decreased levels of HCII were observed in wild-type animals challenged with bacteria or endotoxin. In humans, proteolytically cleaved HCII forms were detected during wounding and in association with bacteria. Thus, the protease-induced uncovering of cryptic epitopes in HCII, which transforms the molecule into a host defense factor, represents a previously unknown regulatory mechanism in HCII biology and innate immunity. PMID:23656734

  17. Tocotrienol-Rich Fraction Ameliorates Antioxidant Defense Mechanisms and Improves Replicative Senescence-Associated Oxidative Stress in Human Myoblasts

    PubMed Central

    Wan Ngah, Wan Zurinah; Abdul Karim, Norwahidah

    2017-01-01

    During aging, oxidative stress affects the normal function of satellite cells, with consequent regeneration defects that lead to sarcopenia. This study aimed to evaluate tocotrienol-rich fraction (TRF) modulation in reestablishing the oxidative status of myoblasts during replicative senescence and to compare the effects of TRF with other antioxidants (α-tocopherol (ATF) and N-acetyl-cysteine (NAC)). Primary human myoblasts were cultured to young, presenescent, and senescent phases. The cells were treated with antioxidants for 24 h, followed by the assessment of free radical generation, lipid peroxidation, antioxidant enzyme mRNA expression and activities, and the ratio of reduced to oxidized glutathione. Our data showed that replicative senescence increased reactive oxygen species (ROS) generation and lipid peroxidation in myoblasts. Treatment with TRF significantly diminished ROS production and decreased lipid peroxidation in senescent myoblasts. Moreover, the gene expression of superoxide dismutase (SOD2), catalase (CAT), and glutathione peroxidase (GPX1) was modulated by TRF treatment, with increased activity of superoxide dismutase and catalase and reduced glutathione peroxidase in senescent myoblasts. In comparison to ATF and NAC, TRF was more efficient in heightening the antioxidant capacity and reducing free radical insults. These results suggested that TRF is able to ameliorate antioxidant defense mechanisms and improves replicative senescence-associated oxidative stress in myoblasts. PMID:28243354

  18. Lifestyle and host defense mechanisms of the dung beetle, Euoniticellus intermedius: the toll signaling pathway.

    PubMed

    Hull, Rodney; Alaouna, Mohamed; Khanyile, Lucky; Byrne, Marcus; Ntwasa, Monde

    2013-01-01

    The dung beetle, Euoniticellus intermedius (Reiche) (Coleoptera: Scarabaeidae) is an important ecological and agricultural agent. Their main activity, the burying of dung, improves quality of the soil and reduces pests that could cause illness in animals. E. intermedius are therefore important for agriculture and for good maintenance of the environment, and are regarded as effective biological control agents for parasites of the gastrointestinal tract in livestock. The ability of E. intermedius to co-exist comfortably with many microorganisms, some of which are important human pathogens, stimulated our interest in its host defense strategies. The aim of this study was to investigate the Toll signaling pathway, which is strongly activated by fungi. Gene expression associated with fungal infection was analyzed by using 2-D gel electrophoresis and mass spectroscopy. Furthermore, the partial adult transcriptome was investigated for the presence of known immune response genes by using high-throughput sequencing and bioinformatics. The results presented here suggest that E. intermedius responds to fungal challenge via the Toll signaling pathway.

  19. Cosmic bombardment V: Threat object-dispersing approaches to active planetary defense

    SciTech Connect

    Teller, E.; Wood, L. |; Ishikawa, M. |; Hyde, R.

    1995-05-24

    Earth-impacting comets and asteroids with diameters {approx}0.03 - 10 km pose the greatest threats to the terrestrial biosphere in terms of impact frequency-weighted impact consequences, and thus are of most concern to designers of active planetary defenses. Specific gravitational binding energies of such objects range from 10{sup -7} to 10{sup -2} J/gm, and are small compared with the specific energies of 1x10{sup 3} to 3x10{sup 3} J/gm required to vaporize objects of typical composition or the specific energies required to pulverize them, which are 10{sup -1} to 10 J/gm. All of these are small compared to the specific kinetic energy of these objects in the Earth- centered frame, which is 2x10{sup 5} to 2x10{sup 6} J/gm. The prospect naturally arises of negating all such threats by deflecting, pulverizing or vaporizing the objects. Pulverization-with-dispersal is an attractive option of reasonable defensive robustness. Examples of such equipments - which employ no explosives of any type - are given. Vaporization is the maximally robust defensive option, and may be invoked to negate threat objects not observed until little time is left until Earth-strike, and pulverization-with-dispersal has proven inadequate. Physically larger threats may be vaporized with nuclear explosives. No contemporary technical means of any kind appear capable of directly dispersing the -100 km diameter scale Charon- class cometary objects recently observed in the outer solar system, although such objects may be deflected to defensively useful extents. Means of implementing defenses of each of these types are proposed for specificity, and areas for optimization noted. Biospheric impacts of threat object debris are briefly considered, for bounding purposes. Experiments are suggested on cometary and asteroidal objects.

  20. Ginkgo biloba Responds to Herbivory by Activating Early Signaling and Direct Defenses

    PubMed Central

    Atsbaha Zebelo, Simon; Foti, Maria; Fliegmann, Judith; Bossi, Simone; Maffei, Massimo E.; Bertea, Cinzia M.

    2012-01-01

    Background Ginkgo biloba (Ginkgoaceae) is one of the most ancient living seed plants and is regarded as a living fossil. G. biloba has a broad spectrum of resistance or tolerance to many pathogens and herbivores because of the presence of toxic leaf compounds. Little is known about early and late events occurring in G. biloba upon herbivory. The aim of this study was to assess whether herbivory by the generalist Spodoptera littoralis was able to induce early signaling and direct defense in G. biloba by evaluating early and late responses. Methodology/Principal Findings Early and late responses in mechanically wounded leaves and in leaves damaged by S. littoralis included plasma transmembrane potential (Vm) variations, time-course changes in both cytosolic calcium concentration ([Ca2+]cyt) and H2O2 production, the regulation of genes correlated to terpenoid and flavonoid biosynthesis, the induction of direct defense compounds, and the release of volatile organic compounds (VOCs). The results show that G. biloba responded to hebivory with a significant Vm depolarization which was associated to significant increases in both [Ca2+]cyt and H2O2. Several defense genes were regulated by herbivory, including those coding for ROS scavenging enzymes and the synthesis of terpenoids and flavonoids. Metabolomic analyses revealed the herbivore-induced production of several flavonoids and VOCs. Surprisingly, no significant induction by herbivory was found for two of the most characteristic G. biloba classes of bioactive compounds; ginkgolides and bilobalides. Conclusions/Significance By studying early and late responses of G. biloba to herbivory, we provided the first evidence that this “living fossil” plant responds to herbivory with the same defense mechanisms adopted by the most recent angiosperms. PMID:22448229

  1. Mitogen-activated protein kinase pathways are required for melatonin-mediated defense responses in plants.

    PubMed

    Lee, Hyoung Yool; Back, Kyoungwhan

    2016-04-01

    Melatonin enhances pathogen resistance by inducing the expression of a number of plant defense-related genes. To examine whether the melatonin-mediated pathogen resistance is associated with mitogen-activated protein kinase (MAPK) cascades, Arabidopsis and tobacco leaves were treated with melatonin and investigated for MAPK activation using an antiphospho-p44/42 MAPK (Erk1/2) monoclonal antibody. Two MAPKs, MPK3 and MPK6, were activated rapidly and transiently by 1 μm melatonin treatment in Arabidopsis. Its tobacco ortholog MAPKs were also activated. The activation of MPK3 and MPK6 by 2-hydroxymelatonin and N-acetylserotonin was also observed, albeit to a lesser degree than that by melatonin. Furthermore, MAPK activation by melatonin was uncoupled from G-protein signaling, because melatonin efficiently activated two MAPKs in a G-protein β knockout mutant (agb1). Suppression of both MPK3 and MPK6 in transgenic Arabidopsis exhibited significant decreases in the induction of defense-related gene expression and pathogen resistance relative to wild-type plants. Using an array of MAP kinase kinase (MKK) knockout mutants, we found that four MKKs, namely MKK4, MKK5, MKK7, and MKK9, are responsible for the activation of MPK3 and MPK6 by melatonin, indicating that melatonin-mediated innate immunity is triggered by MAPK signaling through MKK4/5/7/9-MPK3/6 cascades.

  2. Mechanisms of optimal defense patterns in Nicotiana attenuata: flowering attenuates herbivory-elicited ethylene and jasmonate signaling.

    PubMed

    Diezel, Celia; Allmann, Silke; Baldwin, Ian T

    2011-12-01

    To defend themselves against herbivore attack, plants produce secondary metabolites, which are variously inducible and constitutively deployed, presumably to optimize their fitness benefits in light of their fitness costs. Three phytohormones, jasmonates (JA) and their active forms, the JA-isoleucine (JA-Ile) and ethylene (ET), are known to play central roles in the elicitation of induced defenses, but little is known about how this mediation changes over ontogeny. The Optimal Defense Theory (ODT) predicts changes in the costs and benefits of the different types of defenses and has been usefully extrapolated to their modes of deployment. Here we studied whether the herbivore-induced accumulation of JA, JA-Ile and ET changed over ontogeny in Nicotiana attenuata, a native tobacco in which inducible defenses are particularly well studied. Herbivore-elicited ET production changed dramatically during six developmental stages, from rosette through flowering, decreasing with the elongation of the first corollas during flower development. This decrease was largely recovered within a day after flower removal by decapitation. A similar pattern was found for the herbivore-induced accumulation of JA and JA-Ile. These results are consistent with ODT predictions and suggest that the last steps in floral development control the inducibility of at least three plant hormones, optimizing defense-growth tradeoffs.

  3. Analysis of the Molecular Dialogue Between Gray Mold (Botrytis cinerea) and Grapevine (Vitis vinifera) Reveals a Clear Shift in Defense Mechanisms During Berry Ripening.

    PubMed

    Kelloniemi, Jani; Trouvelot, Sophie; Héloir, Marie-Claire; Simon, Adeline; Dalmais, Bérengère; Frettinger, Patrick; Cimerman, Agnès; Fermaud, Marc; Roudet, Jean; Baulande, Sylvain; Bruel, Christophe; Choquer, Mathias; Couvelard, Linhdavanh; Duthieuw, Mathilde; Ferrarini, Alberto; Flors, Victor; Le Pêcheur, Pascal; Loisel, Elise; Morgant, Guillaume; Poussereau, Nathalie; Pradier, Jean-Marc; Rascle, Christine; Trdá, Lucie; Poinssot, Benoit; Viaud, Muriel

    2015-11-01

    Mature grapevine berries at the harvesting stage (MB) are very susceptible to the gray mold fungus Botrytis cinerea, while veraison berries (VB) are not. We conducted simultaneous microscopic and transcriptomic analyses of the pathogen and the host to investigate the infection process developed by B. cinerea on MB versus VB, and the plant defense mechanisms deployed to stop the fungus spreading. On the pathogen side, our genome-wide transcriptomic data revealed that B. cinerea genes upregulated during infection of MB are enriched in functional categories related to necrotrophy, such as degradation of the plant cell wall, proteolysis, membrane transport, reactive oxygen species (ROS) generation, and detoxification. Quantitative-polymerase chain reaction on a set of representative genes related to virulence and microscopic observations further demonstrated that the infection is also initiated on VB but is stopped at the penetration stage. On the plant side, genome-wide transcriptomic analysis and metabolic data revealed a defense pathway switch during berry ripening. In response to B. cinerea inoculation, VB activated a burst of ROS, the salicylate-dependent defense pathway, the synthesis of the resveratrol phytoalexin, and cell-wall strengthening. On the contrary, in infected MB, the jasmonate-dependent pathway was activated, which did not stop the fungal necrotrophic process.

  4. A novel mechanism for NETosis provides antimicrobial defense at the oral mucosa.

    PubMed

    Mohanty, Tirthankar; Sjögren, Jonathan; Kahn, Fredrik; Abu-Humaidan, Anas H A; Fisker, Niels; Assing, Kristian; Mörgelin, Matthias; Bengtsson, Anders A; Borregaard, Niels; Sørensen, Ole E

    2015-10-29

    Neutrophils are essential for host defense at the oral mucosa and neutropenia or functional neutrophil defects lead to disordered oral homeostasis. We found that neutrophils from the oral mucosa harvested from morning saliva had released neutrophil extracellular traps (undergone NETosis) in vivo. The NETosis was mediated through intracellular signals elicited by binding of sialyl Lewis(X) present on salival mucins to l-selectin on neutrophils. This led to rapid loss of nuclear membrane and intracellular release of granule proteins with subsequent neutrophil extracellular trap (NET) release independent of elastase and reduced NAD phosphate-oxidase activation. The saliva-induced NETs were more DNase-resistant and had higher capacity to bind and kill bacteria than NETs induced by bacteria or by phorbol-myristate acetate. Furthermore, saliva/sialyl Lewis(X) mediated signaling enhanced intracellular killing of bacteria by neutrophils. Saliva from patients with aphthous ulcers and Behçet disease prone to oral ulcers failed to induce NETosis, but for different reasons it demonstrated that disordered homeostasis in the oral cavity may result in deficient saliva-mediated NETosis.

  5. Plant structural complexity and mechanical defenses mediate predator-prey interactions in an odonate-bird system.

    PubMed

    Grof-Tisza, Patrick; LoPresti, Eric; Heath, Sacha K; Karban, Richard

    2017-03-01

    Habitat-forming species provide refuges for a variety of associating species; these refuges may mediate interactions between species differently depending on the functional traits of the habitat-forming species. We investigated refuge provisioning by plants with different functional traits for dragonfly and damselfly (Odonata: Anisoptera and Zygoptera) nymphs emerging from water bodies to molt into their adult stage. During this period, nymphs experience high levels of predation by birds. On the shores of a small pond, plants with mechanical defenses (e.g., thorns and prickles) and high structural complexity had higher abundances of odonate exuviae than nearby plants which lacked mechanical defenses and exhibited low structural complexity. To disentangle the relative effects of these two potentially important functional traits on nymph emergence-site preference and survival, we conducted two fully crossed factorial field experiments using artificial plants. Nymphs showed a strong preference for artificial plants with high structural complexity and to a lesser extent, mechanical defenses. Both functional traits increased nymph survival but through different mechanisms. We suggest that future investigations attempt to experimentally separate the elements contributing to structural complexity to elucidate the mechanistic underpinnings of refuge provisioning.

  6. Recent advances in host defense mechanisms/therapies against oral infectious diseases and consequences for systemic disease.

    PubMed

    Gaffen, S L; Herzberg, M C; Taubman, M A; Van Dyke, T E

    2014-05-01

    The innate and adaptive immune systems are both crucial to oral disease mechanisms and their impact on systemic health status. Greater understanding of these interrelationships will yield opportunities to identify new therapeutic targets to modulate disease processes and/or increase host resistance to infectious or inflammatory insult. The topics addressed reflect the latest advances in our knowledge of the role of innate and adaptive immune systems and inflammatory mechanisms in infectious diseases affecting the oral cavity, including periodontitis and candidiasis. In addition, several potential links with systemic inflammatory conditions, such as cardiovascular disease, are explored. The findings elucidate some of the defense mechanisms utilized by host tissues, including the role of IL-17 in providing immunity to oral candidiasis, the antimicrobial defense of mucosal epithelial cells, and the pro-resolution effects of the natural inflammatory regulators, proresolvins and lipoxins. They also describe the role of immune cells in mediating pathologic bone resorption in periodontal disease. These insights highlight the potential for therapeutic benefit of immunomodulatory interventions that bolster or modulate host defense mechanisms in both oral and systemic disease. Among the promising new therapeutic approaches discussed here are epithelial cell gene therapy, passive immunization against immune cell targets, and the use of proresolvin agents.

  7. Mechanics of soft active materials

    NASA Astrophysics Data System (ADS)

    Zhao, Xuanhe

    Soft active materials, mostly elastomers and polymeric gels, are being developed to mimic a salient feature of life: movement in response to stimuli. For example, when an electric voltage is applied across a layer of a dielectric elastomer, the layer reduces in thickness and expands in area, giving a strain greater than 100%. As another example, in response to a small change of pH or temperature, a hydrogel may absorb a large amount of water and increase its volume over 100 times. The mechanics involved in these processes is important, interesting, and not well understood. This thesis studies large deformations and instabilities in dielectric elastomers and polymeric gels. The thesis first presents a nonlinear field theory for deformable dielectrics. The theory uses measurable quantities to define field variables. The definitions lead to decoupled field equations, and electromechanical coupling enters the theory through material laws. We use the theory to study electromechanical instability and coexistent states in dielectric elastomers. A computational method is also developed to analyze inhomogeneous deformations in complicated structures of dielectric elastomers. The second part of the thesis discusses large deformation and mass transportation in polymeric gels. A gel can undergo large deformation of two modes: local rearrangement and long-range migration. We assume that the local rearrangement is instantaneous, and model the long-range migration by assuming that the solvent molecules diffuse inside the gel. We further study inhomogeneous and anisotropic deformations and instabilities in gels constrained by rigid materials.

  8. Lysozyme and defense peptides as suppressors of phenoloxidase activity in Galleria mellonella.

    PubMed

    Zdybicka-Barabas, Agnieszka; Mak, Paweł; Jakubowicz, Teresa; Cytryńska, Małgorzata

    2014-09-01

    The prophenoloxidase (proPO) cascade supplies quinones and other reactive compounds for melanin formation, protein cross-linking, hemolymph coagulation, and killing of microbial invaders as well as parasites. The high cytotoxicity of the generated compounds requires a strict control of the activation of the proPO system and phenoloxidase (PO) activity to minimize damage to host tissues and cells. The PO activity in hemolymph of Escherichia coli challenged Galleria mellonella larvae increased, with a temporal drop 1 h after the challenge, reaching the highest level 24 h after the challenge. In the present study, a potential role of G. mellonella defense peptides and lysozyme in controlling the proPO system was investigated. The effects of purified defense peptides (anionic peptides 1 and 2, cecropin D-like peptide, Galleria defensin, proline-rich peptides 1 and 2) and lysozyme were analyzed. Four compounds, namely lysozyme, Galleria defensin, proline-rich peptide 1, and anionic peptide 2, decreased the hemolymph PO activity considerably, whereas the others did not affect the enzyme activity level. Our results indicate that these hemolymph factors could play multiple and distinct roles in the insect immune response.

  9. Gender differences in defense mechanisms, ways of coping with stress and sense of identity in adolescent suicide attempts.

    PubMed

    Foto-Özdemir, Dilşad; Akdemir, Devrim; Çuhadaroğlu-Çetin, Füsun

    2016-01-01

    The main aim of this study was to investigate the gender differences in defense mechanisms, ways of coping with stress and identity formation in relation to adolescent suicidal behavior. This study involved 64 adolescents between 12-17 years of age, who were admitted to the emergency service with a suicide attempt. They were evaluated with a semi-structured clinical interview (K-SADS), Ways of Coping Inventory (WCI), Defense Mechanisms Inventory (DMI) and Sense of Identity Assessment Form (SIAF). 60.9% (n = 39) of the adolescents were female, and 39.1% (n=25) were male. There were no statistically significant differences between the girls and the boys with respect to the clinical characteristics of the suicide attempt and the rate of psychiatric disorders. Of the 64 adolescents with suicide attempt, 47 (73.4%) had at least one, and 26 (40.6%) had more than one psychiatric disorder according to K-SADS. Disruptive behavior disorders were more frequent in males, whereas depression was more frequent in girls. The data indicated the importance of identity confusion, major depression and ADHD in adolescents with suicide attempt in both genders. 43.6% (n=17) of the girls and 36% (n=9) of the boys obtained scores higher than the cut-off point of SIAF indicating identity confusion. Professional help seeking and NSSI behaviors before the suicide attempt were more common in adolescents with identity confusion. While there were differences between genders with respect to the defense mechanisms used, no significant difference was found in terms of ways of coping. Evaluation of DMI scores revealed that the turning against object subscale score was significantly higher in boys compared to girls. While evaluating the adolescents at risk, their defense mechanisms, way of coping and sense of identity, as well as their psychiatric diagnosis should be assessed in detail in order to identify the suicidal thoughts and prevent possible suicide attempts.

  10. First evidence for toxic defense based on the multixenobiotic resistance (MXR) mechanism in Daphnia magna.

    PubMed

    Campos, Bruno; Altenburger, Rolf; Gómez, Cristian; Lacorte, Silvia; Piña, Benjamin; Barata, Carlos; Luckenbach, Till

    2014-03-01

    The water flea Daphnia magna is widely used as test species in ecotoxicological bioassays. So far, there is no information available to which extent ATP binding cassette (ABC) transporter based multixenobiotic resistance (MXR) counteracts adverse chemical effects in this species. This, however, would be important for assessing to which extent the bio-active potential of a compound determined with this species depends on this cellular defense. We here present molecular, functional and toxicological studies that provide first evidence for ABC transporter-based MXR in D. magna. We cloned putatively MXR-related partial abcb1, abcc1/3, abcc4 and abcc5 coding sequences; respective transcripts were constitutively expressed in different D. magna life stages. MXR associated efflux activity was monitored in D. magna using the fluorescent substrate dyes rhodamine 123, rhodamine B and calcein-AM combined with inhibitors of human ABCB1 and/or ABCC transporter activities reversin 205, MK571 and cyclosporin A. With inhibitors present, efflux of dye substrates was reduced in D. magna in a concentration-dependent mode, as indicated by elevated accumulation of the dyes in D. magna tissues. In animals pre-exposed to mercury, pentachlorophenol or dacthal applied as inducers of ABC transporter expression, levels of some ABC transporter transcripts were increased in some cases showing that these genes can be chemically induced. Likewise, pre-exposure of animals to these chemicals decreased dye accumulation in tissue, indicating enhanced MXR transporter activity, likely associated with higher transporter protein levels. Toxicity assays with toxic transporter substrates mitoxantrone and chlorambucil that were applied singly and in combination with inhibitors were performed to study the tolerance role of Abcb1 and Abcc efflux transporters in D. magna. Joint toxicities of about half of the binary combinations of test compounds applied (substrate/inhibitor, substrate/substrate, inhibitor

  11. Regulation of the Arabidopsis defense transcriptome.

    PubMed

    Eulgem, Thomas

    2005-02-01

    Transcriptional re-programming is a key step of plant defense in response to pathogen recognition. Microarray analyses combined with genetic and biochemical approaches are now enabling us to study basic principles and details of regulatory mechanisms controlling the defense transcriptome in Arabidopsis. Recent results show that signaling pathways used by different defense systems converge and target overlapping gene sets. Furthermore, a quantitative mechanism common to multiple defense systems modulates transcript levels of these defense-associated genes. Most importantly, some transcription factors have been proven to play a pivotal role in disease resistance. Regulatory circuits linking signaling and gene regulation are emerging, suggesting that a complex interplay of transcriptional activators and repressors fine-tunes expression of the defense transcriptome.

  12. Brief Report: Self-Harm Is Associated with Immature Defense Mechanisms but Not Substance Use in a Nonclinical Scottish Adolescent Sample

    ERIC Educational Resources Information Center

    Brody, Stuart; Carson, Carron Maryjane

    2012-01-01

    It has been unclear whether adolescent deliberate self-harm (DSH) is more associated with substance use or with characterological impairments. Multivariate determination of (N = 114 Scottish adolescents) ever engaging in DSH (Youth Risk Behavior Survey) from alcohol use, other substance use, and immature defense mechanism use (Defense Style…

  13. The Polycomb group gene Bmi1 regulates antioxidant defenses in neurons by repressing p53 pro-oxidant activity

    PubMed Central

    Chatoo, Wassim; Abdouh, Mohamed; David, Jocelyn; Champagne, Marie-Pier; Ferreira, José; Rodier, Francis; Bernier, Gilbert

    2009-01-01

    Aging may be determined by a genetic program and/or by the accumulation rate of molecular damages. Reactive oxygen species (ROS) generated by the mitochondrial metabolism have been postulated to be the central source of molecular damages and imbalance between levels of intracellular ROS and antioxidant defenses is a characteristic of the aging brain. How aging modifies free radicals concentrations and increases the risk to develop most neurodegenerative diseases is poorly understood, however. Here we show that the Polycomb group and oncogene Bmi1 is required in neurons to suppress apoptosis and the induction of a premature aging-like program characterized by reduced antioxidant defenses. Before weaning, Bmi1−/− mice display a progeroid-like ocular and brain phenotype while Bmi1+/− mice, although apparently normal, have reduced lifespan. Bmi1 deficiency in neurons results in increased p19Arf/p53 levels, abnormally high ROS concentrations and hypersensitivity to neurotoxic agents. Most Bmi1 functions on neurons oxidative metabolism are genetically linked to repression of p53 pro-oxidant activity, which also operates in physiological conditions. In Bmi1−/− neurons, p53 and co-repressors accumulate at antioxidant gene promoters, correlating with a repressed chromatin state and antioxidant genes downregulation. These findings provide a molecular mechanism explaining how Bmi1 regulates free radical concentrations and reveal the biological impact of Bmi1 deficiency on neuronal survival and aging. PMID:19144853

  14. IL-15 constrains mast cell-dependent antibacterial defenses by suppressing chymase activities.

    PubMed

    Orinska, Zane; Maurer, Marcus; Mirghomizadeh, Farhad; Bulanova, Elena; Metz, Martin; Nashkevich, Natalia; Schiemann, Florian; Schulmistrat, Jan; Budagian, Vadim; Giron-Michel, Julien; Brandt, Ernst; Paus, Ralf; Bulfone-Paus, Silvia

    2007-08-01

    Sepsis remains a global clinical problem. By using the mouse cecal ligation and puncture model of sepsis, here we identify an important aspect of mast cell (MC)-dependent, innate immune defenses against Gram-negative bacteria by demonstrating that MC protease activity is regulated by interleukin-15 (IL-15). Mouse MCs express both constitutive and lipopolysaccharide-inducible IL-15 and store it intracellularly. Deletion of Il15 in mice markedly increases chymase activities, leading to greater MC bactericidal responses, increased processing and activation of neutrophil-recruiting chemokines, and significantly higher survival rates of mice after septic peritonitis. By showing that intracellular IL-15 acts as a specific negative transcriptional regulator of a mouse MC chymase (mast cell protease-2), we provide evidence that defined MC protease activity is transcriptionally regulated by an intracellularly retained cytokine. Our results identify an unexpected breach in MC-dependent innate immune defenses against sepsis and suggest that inhibiting intracellular IL-15 in MCs may improve survival from sepsis.

  15. Active cell mechanics: Measurement and theory.

    PubMed

    Ahmed, Wylie W; Fodor, Étienne; Betz, Timo

    2015-11-01

    Living cells are active mechanical systems that are able to generate forces. Their structure and shape are primarily determined by biopolymer filaments and molecular motors that form the cytoskeleton. Active force generation requires constant consumption of energy to maintain the nonequilibrium activity to drive organization and transport processes necessary for their function. To understand this activity it is necessary to develop new approaches to probe the underlying physical processes. Active cell mechanics incorporates active molecular-scale force generation into the traditional framework of mechanics of materials. This review highlights recent experimental and theoretical developments towards understanding active cell mechanics. We focus primarily on intracellular mechanical measurements and theoretical advances utilizing the Langevin framework. These developing approaches allow a quantitative understanding of nonequilibrium mechanical activity in living cells. This article is part of a Special Issue entitled: Mechanobiology.

  16. The impact of National Guard activation for homeland defense: employers' perspective.

    PubMed

    Allison-Aipa, Timothy S; De La Rosa, Gabriel M; Stetz, Melba C; Castro, Carl A

    2005-10-01

    Data gathered from a study of reserve component (RC) soldiers who were activated during the spring of 2002, following the terrorist attacks of September 11, 2001, suggested that they were concerned about how the effects of their activation affected their civilian employment. Therefore, the purpose of this study was to obtain this information from the civilian employers of these RC soldiers. Most civilian employers who participated in this study (N = 28) were male (89%) and working in law enforcement (39%). Fifty-six percent of employers gave consent to be interviewed by telephone. Although supervisors reported difficulties in several areas of operation and aspects of the RC activation, they still supported the activation of their RC employees and their military mission. This study is a significant start to illuminating the important roles that both RC employees and their civilian employers play in homeland defense.

  17. Transcriptional analysis of defense mechanisms in upland tetraploid switchgrass to greenbugs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Background: Aphid infestation of switchgrass (Panicum virgatum) has the potential to reduce yields and biomass quality. Although switchgrass-greenbug (Schizaphis graminum; GB) interactions have been studied at the whole plant level, little information is available on plant defense responses at the m...

  18. Zinc triggers signaling mechanisms and defense responses promoting resistance to Alternaria brassicicola in Arabidopsis thaliana.

    PubMed

    Martos, Soledad; Gallego, Berta; Cabot, Catalina; Llugany, Mercè; Barceló, Juan; Poschenrieder, Charlotte

    2016-08-01

    According to the elemental defense hypothesis the accumulation of trace elements by plants may substitute for organic defenses, while the joint effects hypothesis proposes that trace elements and organic defenses can have additive or synergistic effects against pathogens or herbivores. To evaluate these hypotheses the response of the pathosystem Alternaria brassicicola-Arabidopsis thaliana to control (2μM) and surplus (12μM) Zn was evaluated using the camalexin deficient mutant pad3-1 and mtp1-1, a mutant with impaired Zn vacuolar storage, along with the corresponding wildtypes. In vitro, a 50% inhibition of fungal growth was achieved by 440μM Zn. A. thaliana leaves could accumulate equivalent concentrations without harm. In fact, surplus Zn enhanced the resistance of A. thaliana to fungal attack in Columbia (Col-0), Wassilewskija (WS), and mtp1-1. However, surplus Zn was unable to protect pad3-1 demonstrating that Zn cannot substitute for camalexin, the main organic defense in A. thaliana. High, non phytotoxic leaf Zn concentrations enhanced the resistance to A. brassicicola of A. thaliana genotypes able to produce camalexin. This was mainly due to Zn-induced enhancement of the JA/ETH signaling pathway leading to enhanced PAD3 expression. These results support the joint effects hypothesis and highlight the importance of adequate Zn supply for reinforced pathogen resistance.

  19. A background traffic activity analysis in a canonical NATO (North Atlantic Treaty Organization) defense

    SciTech Connect

    Rogers, J.N.; Tooman, T.P.

    1989-04-01

    A canonical defense study in a NATO brigade sector on the northern flank of the US V Corps sector in the Federal Republic of Germany is wargamed to depict the expected vehicular movements during a 24 hour time period. All NATO and Warsaw Pact situations and forces played intentionally portray a ''normal'' battlefield situation, that is one in which events occur according to the established tactics and doctrines for both NATO and WP forces. Activity details which are almost always ignored in broader studies are included. The periodic displacement of high value units (e.g., artillery, air defense, headquarters and target acquisition) to preclude enemy fixing and targeting; the resupply down to company and occasionally platoon level of ammunition, petroleum, rations, etc.; the movement of commanders and staffs; the activity of combat engineers to include site preparation, construction and minefield emplacement; the action of reconnaissance and patrol units; the security of the rear area and POW processing; and the evacuation of casualties are analyzed. The resulting database records the position for every vehicle in both forces at each minute during the period of analysis and is thus an ideal framework for a variety of further studies, such as analyses of intelligence collection devices and modern ordinances. 9 refs., 30 figs., 9 tabs.

  20. A novel mechanism underlying the basic defensive response of macrophages against Mycobacterium infection.

    PubMed

    Iyoda, Takuya; Takada, Muneaki; Fukatsu, Yoshinobu; Kumokoshi, Shunsuke; Fujisawa, Tatsuya; Shimada, Tomokazu; Shimokawa, Noriko; Matsunaga, Takuya; Makino, Kimiko; Doi, Norio; Terada, Hiroshi; Fukai, Fumio

    2014-05-01

    Following inhalation of Mycobacterium tuberculosis, including bacillus Calmette-Guérin (BCG), pathogens enter and grow inside macrophages by taking advantage of their phagocytic mechanisms. Macrophages often fail to eliminate intracellular M. tuberculosis, leading to the induction of host macrophage death. Despite accumulating evidence, the molecular mechanisms underlying M. tuberculosis infection-induced cell death remain controversial. In this study, we show the involvement of two distinct pathways triggered by TLR2 and β2 integrin in BCG infection-induced macrophage apoptosis. First, BCG infection induced activation of ERK1/2, which in turn caused phosphorylation/activation of the proapoptotic protein Bim in mouse macrophage-like Raw 264.7 cells. BCG-infected Raw cells treated with U0126, an MEK/ERK inhibitor, led to the suppression of Bim phosphorylation alongside a remarkable increase in the number of viable macrophages. Small interfering RNA-mediated knockdown of Bim rescued the macrophages from the apoptotic cell death induced by BCG infection. Stimulation with Pam3CSK, a TLR2 agonist, induced macrophage apoptosis with a concomitant increase in the phosphorylation/activation of MEK/ERK and Bim. These observations indicate the important role of the TLR2/MEK/ERK/Bim pathway in BCG infection-induced macrophage apoptosis. Second, we used the β2 integrin agonists C3bi and fibronectin to show that the β2 integrin-derived signal was involved in BCG infection-induced apoptosis, independent of MEK/ERK activation. Interestingly, latex beads coated with Pam3CSK and C3bi were able to induce apoptosis in macrophages to the same extent and specificity as that induced by BCG. Taken together, two distinct pattern-recognition membrane receptors, TLR2 and β2 integrin, acted as triggers in BCG infection-induced macrophage apoptosis, in which MEK/ERK activation played a crucial role following the engagement of TLR2.

  1. Oxidative damage and cellular defense mechanisms in sea urchin models of aging.

    PubMed

    Du, Colin; Anderson, Arielle; Lortie, Mae; Parsons, Rachel; Bodnar, Andrea

    2013-10-01

    The free radical, or oxidative stress, theory of aging proposes that the accumulation of oxidative cellular damage is a major contributor to the aging process and a key determinant of species longevity. This study investigates the oxidative stress theory in a novel model for aging research, the sea urchin. Sea urchins present a unique model for the study of aging because of the existence of species with tremendously different natural life spans, including some species with extraordinary longevity and negligible senescence. Cellular oxidative damage, antioxidant capacity, and proteasome enzyme activities were measured in the tissues of three sea urchin species: short-lived Lytechinus variegatus, long-lived Strongylocentrotus franciscanus, and Strongylocentrotus purpuratus, which has an intermediate life span. Levels of protein carbonyls and 4-hydroxynonenal measured in tissues (muscle, nerve, esophagus, gonad, coelomocytes, ampullae) and 8-hydroxy-2'-deoxyguanosine measured in cell-free coelomic fluid showed no general increase with age. The fluorescent age pigment lipofuscin, measured in muscle, nerve, and esophagus, increased with age; however, it appeared to be predominantly extracellular. Antioxidant mechanisms (total antioxidant capacity, superoxide dismutase) and proteasome enzyme activities were maintained with age. In some instances, levels of oxidative damage were lower and antioxidant activity higher in cells or tissues of the long-lived species compared to the short-lived species; however, further studies are required to determine the relationship between oxidative damage and longevity in these animals. Consistent with the predictions of the oxidative stress theory of aging, the results suggest that negligible senescence is accompanied by a lack of accumulation of cellular oxidative damage with age, and maintenance of antioxidant capacity and proteasome enzyme activities may be important mechanisms to mitigate damage.

  2. Oxidative Damage and Cellular Defense Mechanisms in Sea Urchin Models of Aging

    PubMed Central

    Du, Colin; Anderson, Arielle; Lortie, Mae; Parsons, Rachel; Bodnar, Andrea

    2013-01-01

    The free radical or oxidative stress theory of aging proposes that the accumulation of oxidative cellular damage is a major contributor to the aging process and a key determinant of species longevity. This study investigates the oxidative stress theory in a novel model for aging research, the sea urchin. Sea urchins present a unique model for the study of aging due to the existence of species with tremendously different natural life spans including some species with extraordinary longevity and negligible senescence. Cellular oxidative damage, antioxidant capacity and proteasome enzyme activities were measured in the tissues of three sea urchin species: short-lived Lytechinus variegatus, long-lived Strongylocentrotus franciscanus and Strongylocentrotus purpuratus which has an intermediate lifespan. Levels of protein carbonyls and 4-hydroxynonenal (HNE) measured in tissues (muscle, nerve, esophagus, gonad, coelomocytes, ampullae) and 8-hydroxy-2’-deoxyguanosine (8-OHdG) measured in cell-free coelomic fluid showed no general increase with age. The fluorescent age-pigment lipofuscin measured in muscle, nerve and esophagus, increased with age however it appeared to be predominantly extracellular. Antioxidant mechanisms (total antioxidant capacity, superoxide dismutase) and proteasome enzyme activities were maintained with age. In some instances, levels of oxidative damage were lower and antioxidant activity higher in cells or tissues of the long-lived species compared to the short-lived species, however further studies are required to determine the relationship between oxidative damage and longevity in these animals. Consistent with the predictions of the oxidative stress theory of aging, the results suggest that negligible senescence is accompanied by a lack of accumulation of cellular oxidative damage with age and maintenance of antioxidant capacity and proteasome enzyme activities may be important mechanisms to mitigate damage. PMID:23707327

  3. The integrity of the esophageal mucosa. Balance between offensive and defensive mechanisms.

    PubMed

    Orlando, Roy C

    2010-12-01

    Heartburn is the most common and characteristic symptom of gastroesophageal reflux disease. It ultimately results from contact of refluxed gastric acid with nociceptors within the esophageal mucosa and transmission of this peripheral signal to the central nervous system for cognition. Healthy esophageal epithelium provides an effective barrier between refluxed gastric acid and esophageal nociceptors; but this barrier is vulnerable to attack and damage, particularly by acidic gastric contents. How gastric acid is countered by defensive elements within the esophageal mucosa is a major focus of this discussion. When the defense is successful, the subject is asymptomatic and when unsuccessful, the subject experiences heartburn. Those with heartburn commonly fall into one of three endoscopic types: nonerosive reflux disease, erosive esophagitis and Barrett's esophagus. Although what determines endoscopic type remains unknown; it is proposed herein that inflammation plays a key, modulating role.

  4. NODULES WITH ACTIVATED DEFENSE 1 is required for maintenance of rhizobial endosymbiosis in Medicago truncatula.

    PubMed

    Wang, Chao; Yu, Haixiang; Luo, Li; Duan, Liujian; Cai, Liuyang; He, Xinxing; Wen, Jiangqi; Mysore, Kirankumar S; Li, Guoliang; Xiao, Aifang; Duanmu, Deqiang; Cao, Yangrong; Hong, Zonglie; Zhang, Zhongming

    2016-10-01

    The symbiotic interaction between legume plants and rhizobia results in the formation of root nodules, in which symbiotic plant cells host and harbor thousands of nitrogen-fixing rhizobia. Here, a Medicago truncatula nodules with activated defense 1 (nad1) mutant was identified using reverse genetics methods. The mutant phenotype was characterized using cell and molecular biology approaches. An RNA-sequencing technique was used to analyze the transcriptomic reprogramming of nad1 mutant nodules. In the nad1 mutant plants, rhizobial infection and propagation in infection threads are normal, whereas rhizobia and their symbiotic plant cells become necrotic immediately after rhizobia are released from infection threads into symbiotic cells of nodules. Defense-associated responses were detected in nad1 nodules. NAD1 is specifically present in root nodule symbiosis plants with the exception of Morus notabilis, and the transcript is highly induced in nodules. NAD1 encodes a small uncharacterized protein with two predicted transmembrane helices and is localized at the endoplasmic reticulum. Our data demonstrate a positive role for NAD1 in the maintenance of rhizobial endosymbiosis during nodulation.

  5. Post-translational derepression of invertase activity in source leaves via down-regulation of invertase inhibitor expression is part of the plant defense response.

    PubMed

    Bonfig, Katharina B; Gabler, Andrea; Simon, Uwe K; Luschin-Ebengreuth, Nora; Hatz, Martina; Berger, Susanne; Muhammad, Naseem; Zeier, Jürgen; Sinha, Alok K; Roitsch, Thomas

    2010-11-01

    There is increasing evidence that pathogens do not only elicit direct defense responses, but also cause pronounced changes in primary carbohydrate metabolism. Cell-wall-bound invertases belong to the key regulators of carbohydrate partitioning and source-sink relations. Whereas studies have focused so far only on the transcriptional induction of invertase genes in response to pathogen infection, the role of post-translational regulation of invertase activity has been neglected and was the focus of the present study. Expression analyses revealed that the high mRNA level of one out of three proteinaceous invertase inhibitors in source leaves of Arabidopsis thaliana is strongly repressed upon infection by a virulent strain of Pseudomonas syringae pv. tomato DC3000. This repression is paralleled by a decrease in invertase inhibitor activity. The physiological role of this regulatory mechanism is revealed by the finding that in situ invertase activity was detectable only upon infection by P. syringae. In contrast, a high invertase activity could be measured in vitro in crude and cell wall extracts prepared from both infected and non-infected leaves. The discrepancy between the in situ and in vitro invertase activity of control leaves and the high in situ invertase activity in infected leaves can be explained by the pathogen-dependent repression of invertase inhibitor expression and a concomitant reduction in invertase inhibitor activity. The functional importance of the release of invertase from post-translational inhibition for the defense response was substantiated by the application of the competitive chemical invertase inhibitor acarbose. Post-translational inhibition of extracellular invertase activity by infiltration of acarbose in leaves was shown to increase the susceptibility to P. syringae. The impact of invertase inhibition on spatial and temporal dynamics of the repression of photosynthesis and promotion of bacterial growth during pathogen infection supports

  6. The use of the insanity defense as a jail diversion mechanism for mentally ill persons charged with misdemeanors.

    PubMed

    Schaefer, Michele N; Bloom, Joseph D

    2005-01-01

    Heightened awareness and concern regarding the large number of mentally ill misdemeanants in jails has led to a search for alternatives to jail and to the development nationwide of jail diversion programs for offenders with mental illness. Two such mechanisms-diversion to civil commitment and the use of mental health courts-are briefly reviewed. In Oregon, however, a rather unique mechanism is used to defer mentally ill misdemeanants (in addition to felons) from the criminal justice system: the insanity defense, with subsequent placement of the individual under Psychiatric Security Review Board jurisdiction. Statistics regarding such use from 1978 to 2001 are provided. The authors compare and contrast this jail alternative with both mental health courts and diversion to civil commitment, and discuss questions related to the feasibility of larger-scale use of this mechanism.

  7. Activity of Potent and Selective Host Defense Peptide Mimetics in Mouse Models of Oral Candidiasis

    PubMed Central

    Ryan, Lisa K.; Freeman, Katie B.; Masso-Silva, Jorge A.; Falkovsky, Klaudia; Aloyouny, Ashwag; Markowitz, Kenneth; Hise, Amy G.; Fatahzadeh, Mahnaz; Scott, Richard W.

    2014-01-01

    There is a strong need for new broadly active antifungal agents for the treatment of oral candidiasis that not only are active against many species of Candida, including drug-resistant strains, but also evade microbial countermeasures which may lead to resistance. Host defense peptides (HDPs) can provide a foundation for the development of such agents. Toward this end, we have developed fully synthetic, small-molecule, nonpeptide mimetics of the HDPs that improve safety and other pharmaceutical properties. Here we describe the identification of several HDP mimetics that are broadly active against C. albicans and other species of Candida, rapidly fungicidal, and active against yeast and hyphal cultures and that exhibit low cytotoxicity for mammalian cells. Importantly, specificity for Candida over commensal bacteria was also evident, thereby minimizing potential damage to the endogenous microbiome which otherwise could favor fungal overgrowth. Three compounds were tested as topical agents in two different mouse models of oral candidiasis and were found to be highly active. Following single-dose administrations, total Candida burdens in tongues of infected animals were reduced up to three logs. These studies highlight the potential of HDP mimetics as a new tool in the antifungal arsenal for the treatment of oral candidiasis. PMID:24752272

  8. Low Concentrations of Hydrogen Peroxide Activate the Antioxidant Defense System in Human Sperm Cells.

    PubMed

    Evdokimov, V V; Barinova, K V; Turovetskii, V B; Muronetz, V I; Schmalhausen, E V

    2015-09-01

    The effect of low concentrations of hydrogen peroxide (10-100 µM) on sperm motility and on the activity of the sperm enzyme glyceraldehyde-3-phosphate dehydrogenase (GAPDS) was investigated. Incubation of semen samples with 10 and 100 µM hydrogen peroxide increased the content of spermatozoa with progressive motility by 20 and 18%, respectively, and enhanced the activity of GAPDS in the sperm cells by 27 and 20% compared to a semen sample incubated without additions. It was also found that incubation with 10 µM hydrogen peroxide increased the content of reduced glutathione (GSH) in sperm cells by 50% on average compared to that in the control samples. It is supposed that low concentrations of hydrogen peroxide activate the pentose phosphate pathway, resulting in NADPH synthesis and the reduction of the oxidized glutathione by glutathione reductase yielding GSH. The formed GSH reduces the oxidized cysteine residues of the GAPDS active site, increasing the activity of the enzyme, which in turn enhances the content of sperm cells with progressive motility. Thus, the increase in motile spermatozoa in the presence of low concentrations of hydrogen peroxide can serve as an indicator of normal functioning of the antioxidant defense system in sperm cells.

  9. Secreted human glycyl-tRNA synthetase implicated in defense against ERK-activated tumorigenesis.

    PubMed

    Park, Min Chul; Kang, Taehee; Jin, Da; Han, Jung Min; Kim, Sang Bum; Park, Yun Jung; Cho, Kiwon; Park, Young Woo; Guo, Min; He, Weiwei; Yang, Xiang-Lei; Schimmel, Paul; Kim, Sunghoon

    2012-03-13

    Although adaptive systems of immunity against tumor initiation and destruction are well investigated, less understood is the role, if any, of endogenous factors that have conventional functions. Here we show that glycyl-tRNA synthetase (GRS), an essential component of the translation apparatus, circulates in serum and can be secreted from macrophages in response to Fas ligand that is released from tumor cells. Through cadherin (CDH)6 (K-cadherin), GRS bound to different ERK-activated tumor cells, and released phosphatase 2A (PP2A) from CDH6. The activated PP2A then suppressed ERK signaling through dephosphorylation of ERK and induced apoptosis. These activities were inhibited by blocking GRS with a soluble fragment of CDH6. With in vivo administration of GRS, growth of tumors with a high level of CDH6 and ERK activation were strongly suppressed. Our results implicate a conventional cytoplasmic enzyme in translation as an intrinsic component of the defense against ERK-activated tumor formation.

  10. Antioxidant defense parameters as predictive biomarkers for fermentative capacity of active dried wine yeast.

    PubMed

    Gamero-Sandemetrio, Esther; Gómez-Pastor, Rocío; Matallana, Emilia

    2014-08-01

    The production of active dried yeast (ADY) is a common practice in industry for the maintenance of yeast starters and as a means of long term storage. The process, however, causes multiple cell injuries, with oxidative damage being one of the most important stresses. Consequentially, dehydration tolerance is a highly appreciated property in yeast for ADY production. In this study we analyzed the cellular redox environment in three Saccharomyces cerevisiae wine strains, which show markedly different fermentative capacities after dehydration. To measure/quantify the effect of dehydration on the S. cerevisiae strains, we used: (i) fluorescent probes; (ii) antioxidant enzyme activities; (ii) intracellular damage; (iii) antioxidant metabolites; and (iv) gene expression, to select a minimal set of biochemical parameters capable of predicting desiccation tolerance in wine yeasts. Our results show that naturally enhanced antioxidant defenses prevent oxidative damage after wine yeast biomass dehydration and improve fermentative capacity. Based on these results we chose four easily assayable parameters/biomarkers for the selection of industrial yeast strains of interest for ADY production: trehalose and glutathione levels, and glutathione reductase and catalase enzymatic activities. Yeast strains selected in accordance with this process display high levels of trehalose, low levels of oxidized glutathione, a high induction of glutathione reductase activity, as well as a high basal level and sufficient induction of catalase activity, which are properties inherent in superior ADY strains.

  11. Activation of the Nrf2 Cell Defense Pathway by Ancient Foods: Disease Prevention by Important Molecules and Microbes Lost from the Modern Western Diet.

    PubMed

    Senger, Donald R; Li, Dan; Jaminet, Shou-Ching; Cao, Shugeng

    2016-01-01

    The Nrf2 (NFE2L2) cell defense pathway protects against oxidative stress and disorders including cancer and neurodegeneration. Although activated modestly by oxidative stress alone, robust activation of the Nrf2 defense mechanism requires the additional presence of co-factors that facilitate electron exchange. Various molecules exhibit this co-factor function, including sulforaphane from cruciferous vegetables. However, natural co-factors that are potent and widely available from dietary sources have not been identified previously. The objectives of this study were to investigate support of the Nrf2 cell defense pathway by the alkyl catechols: 4-methylcatechol, 4-vinylcatechol, and 4-ethylcatechol. These small electrochemicals are naturally available from numerous sources but have not received attention. Findings reported here illustrate that these compounds are indeed potent co-factors for activation of the Nrf2 pathway both in vitro and in vivo. Each strongly supports expression of Nrf2 target genes in a variety of human cell types; and, in addition, 4-ethylcatechol is orally active in mice. Furthermore, findings reported here identify important and previously unrecognized sources of these compounds, arising from biotransformation of common plant compounds by lactobacilli that express phenolic acid decarboxylase. Thus, for example, Lactobacillus plantarum, Lactobacillus brevis, and Lactobacillus collinoides, which are consumed from a diet rich in traditionally fermented foods and beverages, convert common phenolic acids found in fruits and vegetables to 4-vinylcatechol and/or 4-ethylcatechol. In addition, all of the alkyl catechols are found in wood smoke that was used widely for food preservation. Thus, the potentially numerous sources of alkyl catechols in traditional foods suggest that these co-factors were common in ancient diets. However, with radical changes in food preservation, alkyl catechols have been lost from modern foods. The absence of alkyl

  12. Activation of the Nrf2 Cell Defense Pathway by Ancient Foods: Disease Prevention by Important Molecules and Microbes Lost from the Modern Western Diet

    PubMed Central

    Senger, Donald R.; Li, Dan; Jaminet, Shou-Ching; Cao, Shugeng

    2016-01-01

    The Nrf2 (NFE2L2) cell defense pathway protects against oxidative stress and disorders including cancer and neurodegeneration. Although activated modestly by oxidative stress alone, robust activation of the Nrf2 defense mechanism requires the additional presence of co-factors that facilitate electron exchange. Various molecules exhibit this co-factor function, including sulforaphane from cruciferous vegetables. However, natural co-factors that are potent and widely available from dietary sources have not been identified previously. The objectives of this study were to investigate support of the Nrf2 cell defense pathway by the alkyl catechols: 4-methylcatechol, 4-vinylcatechol, and 4-ethylcatechol. These small electrochemicals are naturally available from numerous sources but have not received attention. Findings reported here illustrate that these compounds are indeed potent co-factors for activation of the Nrf2 pathway both in vitro and in vivo. Each strongly supports expression of Nrf2 target genes in a variety of human cell types; and, in addition, 4-ethylcatechol is orally active in mice. Furthermore, findings reported here identify important and previously unrecognized sources of these compounds, arising from biotransformation of common plant compounds by lactobacilli that express phenolic acid decarboxylase. Thus, for example, Lactobacillus plantarum, Lactobacillus brevis, and Lactobacillus collinoides, which are consumed from a diet rich in traditionally fermented foods and beverages, convert common phenolic acids found in fruits and vegetables to 4-vinylcatechol and/or 4-ethylcatechol. In addition, all of the alkyl catechols are found in wood smoke that was used widely for food preservation. Thus, the potentially numerous sources of alkyl catechols in traditional foods suggest that these co-factors were common in ancient diets. However, with radical changes in food preservation, alkyl catechols have been lost from modern foods. The absence of alkyl

  13. Defensive activation during the rubber hand illusion: Ownership versus proprioceptive drift.

    PubMed

    Riemer, Martin; Bublatzky, Florian; Trojan, Jörg; Alpers, Georg W

    2015-07-01

    A strong link between body perception and emotional experience has been proposed. To examine the interaction between body perception and anticipatory anxiety, two well-established paradigms were combined: The rubber hand illusion (RHI) and the threat-of-shock paradigm. An artificial hand and the participants' own hand (hidden from sight) were touched synchronously or asynchronously, while either threat-of-shock or safety was cued. Potentiated startle reflexes and enhanced skin conductance responses were observed during threat as compared to safety conditions, but threat conditions did not interact with illusory body perceptions. Thus, defense system activation was not modulated by altered body representations. Physiological responses increased with the sense of ownership for the artificial limb, but not with proprioceptive drift towards its location. The results indicate that ownership ratings and proprioceptive drift capture different aspects of the RHI. The study presents a new approach to investigate the relationship between body representations and emotional states.

  14. Identification of Synthetic and Natural Host Defense Peptides with Leishmanicidal Activity

    PubMed Central

    Marr, A. K.; Cen, S.; Hancock, R. E. W.

    2016-01-01

    Leishmania parasites are a major public health problem worldwide. Effective treatment of leishmaniasis is hampered by the high incidence of adverse effects to traditional drug therapy and the emergence of resistance to current therapeutics. A vaccine is currently not available. Host defense peptides have been investigated as novel therapeutic agents against a wide range of pathogens. Here we demonstrate that the antimicrobial peptide LL-37 and the three synthetic peptides E6, L-1018, and RI-1018 exhibit leishmanicidal activity against promastigotes and intramacrophage amastigotes of Leishmania donovani and Leishmania major. We also report that the Leishmania protease/virulence factor GP63 confers protection to Leishmania from the cytolytic properties of all l-form peptides (E6, L-1018, and LL-37) but not the d-form peptide RI-1018. The results suggest that RI-1018, E6, and LL-37 are promising peptides to develop further into components for antileishmanial therapy. PMID:26883699

  15. Pterostilbene Decreases the Antioxidant Defenses of Aggressive Cancer Cells In Vivo: A Physiological Glucocorticoids- and Nrf2-Dependent Mechanism

    PubMed Central

    Benlloch, María; Obrador, Elena; Valles, Soraya L.; Rodriguez, María L.; Sirerol, J. Antoni; Alcácer, Javier; Pellicer, José A.; Salvador, Rosario; Cerdá, Concha; Sáez, Guillermo T.

    2016-01-01

    Abstract Aims: Polyphenolic phytochemicals have anticancer properties. However, in mechanistic studies, lack of correlation with the bioavailable concentrations is a critical issue. Some reports had suggested that these molecules downregulate the stress response, which may affect growth and the antioxidant protection of malignant cells. Initially, we studied this potential underlying mechanism using different human melanomas (with genetic backgrounds correlating with most melanomas), growing in nude mice as xenografts, and pterostilbene (Pter, a natural dimethoxylated analog of resveratrol). Results: Intravenous administration of Pter decreased human melanoma growth in vivo. However, Pter, at levels measured within the tumors, did not affect melanoma growth in vitro. Pter inhibited pituitary production of the adrenocorticotropin hormone (ACTH), decreased plasma levels of corticosterone, and thereby downregulated the glucocorticoid receptor- and nuclear factor (erythroid-derived 2)-like 2 (Nrf2)-dependent antioxidant defense system in growing melanomas. Exogenous corticosterone or genetically induced Nrf2 overexpression in melanoma cells prevented the inhibition of tumor growth and decreased antioxidant defenses in these malignant cells. These effects and mechanisms were also found in mice bearing different human pancreatic cancers. Glutathione depletion (selected as an antimelanoma strategy) facilitated the complete elimination by chemotherapy of melanoma cells isolated from mice treated with Pter. Innovation: Although bioavailability-related limitations may preclude direct anticancer effects in vivo, natural polyphenols may also interfere with the growth and defense of cancer cells by downregulating the pituitary gland-dependent ACTH synthesis. Conclusions: Pter downregulates glucocorticoid production, thus decreasing the glucocorticoid receptor and Nrf2-dependent signaling/transcription and the antioxidant protection of melanoma and pancreatic cancer cells

  16. Assessing ego defense mechanisms by questionnaire: psychometric properties and psychopathological correlates of the Greek version of the Plutchik's Life Style Index.

    PubMed

    Hyphantis, Thomas; Goulia, Panagiota; Floros, George D; Iconomou, Gregoris; Pappas, Argiro-Irene; Karaivazoglou, Katerina; Assimakopoulos, Konstantinos

    2011-11-01

    The Life Style Index (LSI; Plutchik, Kellerman, & Conte, 1979 ) was designed to assess defense mechanisms, assuming that their use is related to specific affective states and diagnostic concepts. We aimed to assess the psychometric properties of its Greek version and its relation to psychopathological symptoms. The LSI was back-translated into Greek and was administered to 1,261 participants. Six factors were identified, 5 of them largely corresponding to the original version's defenses (compensation, denial, projection, reaction formation, and repression). The sixth factor, named regressive emotionality, included mainly the original scale's regression and displacement factors. Test-retest reliabilities, internal consistencies, and construct validity were quite satisfactory. Most defenses were able to discriminate psychiatric patients from healthy participants and were associated with specific psychopathological symptoms in a theoretically expected mode, further supporting the validity of the Greek version. Our findings suggest that the LSI, based on both psychoevolutionary and psychoanalytic theory, can provide a solid ground for assessing ego defense mechanisms.

  17. Microbial modulation of bacoside A biosynthetic pathway and systemic defense mechanism in Bacopa monnieri under Meloidogyne incognita stress

    PubMed Central

    Gupta, Rupali; Singh, Akanksha; Srivastava, Madhumita; Singh, Vivek; Gupta, M. M.; Pandey, Rakesh

    2017-01-01

    Plant-associated beneficial microbes have been explored to fulfill the imperative function for plant health. However, their impact on the host secondary metabolite production and nematode disease management remains elusive. Our present work has shown that chitinolytic microbes viz., Chitiniphilus sp. MTN22 and Streptomyces sp. MTN14 singly as well as in combination modulated the biosynthetic pathway of bacoside A and systemic defense mechanism against Meloidogyne incognita in Bacopa monnieri. Interestingly, expression of bacoside biosynthetic pathway genes (3-Hydroxy-3-methylglutaryl coenzyme A reductase, mevalonate diphosphate decarboxylase, and squalene synthase) were upregulated in plants treated with the microbial combination in the presence as well as in absence of M. incognita stress. These microbes not only augmented bacoside A production (1.5 fold) but also strengthened host resistance via enhancement in chlorophyll a, defense enzymes and phenolic compounds like gallic acid, syringic acid, ferulic acid and cinnamic acid. Furthermore, elevated lignification and callose deposition in the microbial combination treated plants corroborate well with the above findings. Overall, the results provide novel insights into the underlying mechanisms of priming by beneficial microbes and underscore their capacity to trigger bacoside A production in B. monnieri under biotic stress. PMID:28157221

  18. Microbial modulation of bacoside A biosynthetic pathway and systemic defense mechanism in Bacopa monnieri under Meloidogyne incognita stress.

    PubMed

    Gupta, Rupali; Singh, Akanksha; Srivastava, Madhumita; Singh, Vivek; Gupta, M M; Pandey, Rakesh

    2017-02-03

    Plant-associated beneficial microbes have been explored to fulfill the imperative function for plant health. However, their impact on the host secondary metabolite production and nematode disease management remains elusive. Our present work has shown that chitinolytic microbes viz., Chitiniphilus sp. MTN22 and Streptomyces sp. MTN14 singly as well as in combination modulated the biosynthetic pathway of bacoside A and systemic defense mechanism against Meloidogyne incognita in Bacopa monnieri. Interestingly, expression of bacoside biosynthetic pathway genes (3-Hydroxy-3-methylglutaryl coenzyme A reductase, mevalonate diphosphate decarboxylase, and squalene synthase) were upregulated in plants treated with the microbial combination in the presence as well as in absence of M. incognita stress. These microbes not only augmented bacoside A production (1.5 fold) but also strengthened host resistance via enhancement in chlorophyll a, defense enzymes and phenolic compounds like gallic acid, syringic acid, ferulic acid and cinnamic acid. Furthermore, elevated lignification and callose deposition in the microbial combination treated plants corroborate well with the above findings. Overall, the results provide novel insights into the underlying mechanisms of priming by beneficial microbes and underscore their capacity to trigger bacoside A production in B. monnieri under biotic stress.

  19. Domestic chickens activate a piRNA defense against avian leukosis virus

    PubMed Central

    Sun, Yu Huining; Xie, Li Huitong; Zhuo, Xiaoyu; Chen, Qiang; Ghoneim, Dalia; Zhang, Bin; Jagne, Jarra; Yang, Chengbo; Li, Xin Zhiguo

    2017-01-01

    PIWI-interacting RNAs (piRNAs) protect the germ line by targeting transposable elements (TEs) through the base-pair complementarity. We do not know how piRNAs co-evolve with TEs in chickens. Here we reported that all active TEs in the chicken germ line are targeted by piRNAs, and as TEs lose their activity, the corresponding piRNAs erode away. We observed de novo piRNA birth as host responds to a recent retroviral invasion. Avian leukosis virus (ALV) has endogenized prior to chicken domestication, remains infectious, and threatens poultry industry. Domestic fowl produce piRNAs targeting ALV from one ALV provirus that was known to render its host ALV resistant. This proviral locus does not produce piRNAs in undomesticated wild chickens. Our findings uncover rapid piRNA evolution reflecting contemporary TE activity, identify a new piRNA acquisition modality by activating a pre-existing genomic locus, and extend piRNA defense roles to include the period when endogenous retroviruses are still infectious. DOI: http://dx.doi.org/10.7554/eLife.24695.001 PMID:28384097

  20. RNase 7 in Cutaneous Defense

    PubMed Central

    Rademacher, Franziska; Simanski, Maren; Harder, Jürgen

    2016-01-01

    RNase 7 belongs to the RNase A superfamily and exhibits a broad spectrum of antimicrobial activity against various microorganisms. RNase 7 is expressed in human skin, and expression in keratinocytes can be induced by cytokines and microbes. These properties suggest that RNase 7 participates in innate cutaneous defense. In this review, we provide an overview about the role of RNase 7 in cutaneous defense with focus on the molecular mechanism of the antimicrobial activity of RNase 7, the regulation of RNase 7 expression, and the role of RNase 7 in skin diseases. PMID:27089327

  1. The impact of membrane lipid composition on macrophage activation in the immune defense against Rhodococcus equi and Pseudomonas aeruginosa.

    PubMed

    Schoeniger, Axel; Adolph, Stephanie; Fuhrmann, Herbert; Schumann, Julia

    2011-01-01

    Nutritional fatty acids are known to have an impact on membrane lipid composition of body cells, including cells of the immune system, thus providing a link between dietary fatty acid uptake, inflammation and immunity. In this study we reveal the significance of macrophage membrane lipid composition on gene expression and cytokine synthesis thereby highlighting signal transduction processes, macrophage activation as well as macrophage defense mechanisms. Using RAW264.7 macrophages as a model system, we identified polyunsaturated fatty acids (PUFA) of both the n-3 and the n-6 family to down-regulate the synthesis of: (i) the pro-inflammatory cytokines IL-1β, IL-6 and TNF-α; (ii) the co-stimulatory molecule CD86; as well as (iii) the antimicrobial polypeptide lysozyme. The action of the fatty acids partially depended on the activation status of the macrophages. It is particularly important to note that the anti-inflammatory action of the PUFA could also be seen in case of infection of RAW264.7 with viable microorganisms of the genera R. equi and P. aeruginosa. In summary, our data provide strong evidence that PUFA from both the n-3 and the n-6 family down-regulate inflammation processes in context of chronic infections caused by persistent pathogens.

  2. Mechanism for the activation of glutamate receptors

    Cancer.gov

    Scientists at the NIH have used a technique called cryo-electron microscopy to determine a molecular mechanism for the activation and desensitization of ionotropic glutamate receptors, a prominent class of neurotransmitter receptors in the brain and spina

  3. Sulforaphane prevents pulmonary damage in response to inhaled arsenic by activating the Nrf2-defense response

    SciTech Connect

    Zheng, Yi; Tao, Shasha; Lian, Fangru; Chau, Binh T.; Chen, Jie; Sun, Guifan; Fang, Deyu; Lantz, R. Clark; Zhang, Donna D.

    2012-12-15

    Exposure to arsenic is associated with an increased risk of lung disease. Novel strategies are needed to reduce the adverse health effects associated with arsenic exposure in the lung. Nrf2, a transcription factor that mediates an adaptive cellular defense response, is effective in detoxifying environmental insults and prevents a broad spectrum of diseases induced by environmental exposure to harmful substances. In this report, we tested whether Nrf2 activation protects mice from arsenic-induced toxicity. We used an in vivo arsenic inhalation model that is highly relevant to low environmental human exposure to arsenic-containing dusts. Two-week exposure to arsenic-containing dust resulted in pathological alterations, oxidative DNA damage, and mild apoptotic cell death in the lung; all of which were blocked by sulforaphane (SF) in an Nrf2-dependent manner. Mechanistically, SF-mediated activation of Nrf2 alleviated inflammatory responses by modulating cytokine production. This study provides strong evidence that dietary intervention targeting Nrf2 activation is a feasible approach to reduce adverse health effects associated with arsenic exposure. -- Highlights: ► Exposed to arsenic particles and/or SF have elevated Nrf2 and its target genes. ► Sulforaphane prevents pathological alterations, oxidative damage and cell death. ► Sulforaphane alleviates infiltration of inflammatory cells into the lungs. ► Sulforaphane suppresses arsenic-induced proinflammatory cytokine production.

  4. Oxidative stress and antioxidant defense mechanisms linked to exercise during cardiopulmonary and metabolic disorders.

    PubMed

    Fisher-Wellman, Kelsey; Bell, Heather K; Bloomer, Richard J

    2009-01-01

    Oxidative stress has been implicated in the pathophysiology of multiple human diseases, in addition to the aging process. Although various stimuli exist, acute exercise is known to induce a transient increase in reactive oxygen and nitrogen species (RONS), evident by several reports of increased oxidative damage following acute bouts of aerobic and anaerobic exercise. Although the results are somewhat mixed and appear disease dependent, individuals with chronic disease experience an exacerbation in oxidative stress following acute exercise when compared to healthy individuals. However, this increased oxidant stress may serve as a necessary "signal" for the upregulation in antioxidant defenses, thereby providing protection against subsequent exposure to prooxidant environments within susceptible individuals. Here we present studies related to both acute exercise-induced oxidative stress in those with disease, in addition to studies focused on adaptations resulting from increased RONS exposure associated with chronic exercise training in persons with disease.

  5. Defense mechanisms against herbivory in Picea: sequence evolution and expression regulation of gene family members in the phenylpropanoid pathway

    PubMed Central

    2011-01-01

    the evolution of plant defense mechanisms against insect pests and provide substantial potential for the functional characterization of several not yet resolved alternative pathways in plant defenses. PMID:22177423

  6. The GraS Sensor in Staphylococcus aureus Mediates Resistance to Host Defense Peptides Differing in Mechanisms of Action

    PubMed Central

    Chaili, Siyang; Cheung, Ambrose L.; Bayer, Arnold S.; Xiong, Yan Q.; Waring, Alan J.; Memmi, Guido; Donegan, Niles; Yang, Soo-Jin

    2015-01-01

    Staphylococcus aureus uses the two-component regulatory system GraRS to sense and respond to host defense peptides (HDPs). However, the mechanistic impact of GraS or its extracellular sensing loop (EL) on HDP resistance is essentially unexplored. Strains with null mutations in the GraS holoprotein (ΔgraS) or its EL (ΔEL) were compared for mechanisms of resistance to HDPs of relevant immune sources: neutrophil α-defensin (human neutrophil peptide 1 [hNP-1]), cutaneous β-defensin (human β-defensin 2 [hBD-2]), or the platelet kinocidin congener RP-1. Actions studied by flow cytometry included energetics (ENR); membrane permeabilization (PRM); annexin V binding (ANX), and cell death protease activation (CDP). Assay conditions simulated bloodstream (pH 7.5) or phagolysosomal (pH 5.5) pH contexts. S. aureus strains were more susceptible to HDPs at pH 7.5 than at pH 5.5, and each HDP exerted a distinct effect signature. The impacts of ΔgraS and ΔΕL on HDP resistance were peptide and pH dependent. Both mutants exhibited defects in ANX response to hNP-1 or hBD-2 at pH 7.5, but only hNP-1 did so at pH 5.5. Both mutants exhibited hyper-PRM, -ANX, and -CDP responses to RP-1 at both pHs and hypo-ENR at pH 5.5. The actions correlated with ΔgraS or ΔΕL hypersusceptibility to hNP-1 or RP-1 (but not hBD-2) at pH 7.5 and to all study HDPs at pH 5.5. An exogenous EL mimic protected mutant strains from hNP-1 and hBD-2 but not RP-1, indicating that GraS and its EL play nonredundant roles in S. aureus survival responses to specific HDPs. These findings suggest that GraS mediates specific resistance countermeasures to HDPs in immune contexts that are highly relevant to S. aureus pathogenesis in humans. PMID:26597988

  7. 10 CFR 50.13 - Attacks and destructive acts by enemies of the United States; and defense activities.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 1 2014-01-01 2014-01-01 false Attacks and destructive acts by enemies of the United States; and defense activities. 50.13 Section 50.13 Energy NUCLEAR REGULATORY COMMISSION DOMESTIC... the effects of (a) attacks and destructive acts, including sabotage, directed against the facility...

  8. 10 CFR 50.13 - Attacks and destructive acts by enemies of the United States; and defense activities.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 1 2013-01-01 2013-01-01 false Attacks and destructive acts by enemies of the United States; and defense activities. 50.13 Section 50.13 Energy NUCLEAR REGULATORY COMMISSION DOMESTIC... the effects of (a) attacks and destructive acts, including sabotage, directed against the facility...

  9. 18 CFR 2.60 - Facilities and activities during an emergency-accounting treatment of defense-related expenditures.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 18 Conservation of Power and Water Resources 1 2013-04-01 2013-04-01 false Facilities and activities during an emergency-accounting treatment of defense-related expenditures. 2.60 Section 2.60 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY COMMISSION, DEPARTMENT OF ENERGY...

  10. 18 CFR 2.60 - Facilities and activities during an emergency-accounting treatment of defense-related expenditures.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 18 Conservation of Power and Water Resources 1 2010-04-01 2010-04-01 false Facilities and activities during an emergency-accounting treatment of defense-related expenditures. 2.60 Section 2.60 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY COMMISSION, DEPARTMENT OF ENERGY...

  11. 18 CFR 2.60 - Facilities and activities during an emergency-accounting treatment of defense-related expenditures.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 18 Conservation of Power and Water Resources 1 2012-04-01 2012-04-01 false Facilities and activities during an emergency-accounting treatment of defense-related expenditures. 2.60 Section 2.60 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY COMMISSION, DEPARTMENT OF ENERGY...

  12. 10 CFR 50.13 - Attacks and destructive acts by enemies of the United States; and defense activities.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 1 2012-01-01 2012-01-01 false Attacks and destructive acts by enemies of the United States; and defense activities. 50.13 Section 50.13 Energy NUCLEAR REGULATORY COMMISSION DOMESTIC... the effects of (a) attacks and destructive acts, including sabotage, directed against the facility...

  13. Chemical and Mechanical Defenses Vary among Maternal Lines and Leaf Ages in Verbascum thapsus L. (Scrophulariaceae) and Reduce Palatability to a Generalist Insect

    PubMed Central

    Alba, Christina; Bowers, M. Deane; Blumenthal, Dana; Hufbauer, Ruth A.

    2014-01-01

    Intra-specific variation in host-plant quality affects herbivore foraging decisions and, in turn, herbivore foraging decisions mediate plant fitness. In particular, variation in defenses against herbivores, both among and within plants, shapes herbivore behavior. If variation in defenses is genetically based, it can respond to natural selection by herbivores. We quantified intra-specific variation in iridoid glycosides, trichome length, and leaf strength in common mullein (Verbascum thapsus L, Scrophulariaceae) among maternal lines within a population and among leaves within plants, and related this variation to feeding preferences of a generalist herbivore, Trichopulsia ni Hübner. We found significant variation in all three defenses among maternal lines, with T. ni preferring plants with lower investment in chemical, but not mechanical, defense. Within plants, old leaves had lower levels of all defenses than young leaves, and were strongly preferred by T. ni. Caterpillars also preferred leaves with trichomes removed to leaves with trichomes intact. Differences among maternal lines indicate that phenotypic variation in defenses likely has a genetic basis. Furthermore, these results reveal that the feeding behaviors of T. ni map onto variation in plant defense in a predictable way. This work highlights the importance of variation in host-plant quality in driving interactions between plants and their herbivores. PMID:25127229

  14. When Threat Is Near, Get Out of Here: Dynamics of Defensive Behavior During Freezing and Active Avoidance.

    PubMed

    Löw, Andreas; Weymar, Mathias; Hamm, Alfons O

    2015-11-01

    When detecting a threat, humans and other animals engage in defensive behaviors and supporting physiological adjustments that vary with threat imminence and potential response options. In the present study, we shed light on the dynamics of defensive behaviors and associated physiological adjustments in humans using multiple psychophysiological and brain measures. When participants were exposed to a dynamically approaching, uncontrollable threat, attentive freezing was augmented, as indicated by an increase in skin conductance, fear bradycardia, and potentiation of the startle reflex. In contrast, when participants had the opportunity to actively avoid the approaching threat, attention switched to response preparation, as indicated by an inhibition of the startle magnitude and by a sharp drop of the probe-elicited P3 component of the evoked brain potentials. These new findings on the dynamics of defensive behaviors form an important intersection between animal and human research and have important implications for understanding fear and anxiety-related disorders.

  15. De novo Transcriptome Analysis Reveals Distinct Defense Mechanisms by Young and Mature Leaves of Hevea brasiliensis (Para Rubber Tree)

    PubMed Central

    Fang, Yongjun; Mei, Hailiang; Zhou, Binhui; Xiao, Xiaohu; Yang, Meng; Huang, Yacheng; Long, Xiangyu; Hu, Songnian; Tang, Chaorong

    2016-01-01

    Along with changes in morphology in the course of maturation, leaves of Hevea brasiliensis become more resistant to leaf diseases, including the South American Leaf Blight (SALB), a devastating fungal disease of this economically important tree species. To understand the underlying mechanisms of this defense, and to identify the candidate genes involved, we sequenced the Hevea leaf transcriptome at four developmental stages (I to IV) by Illumina sequencing. A total of 62.6 million high-quality reads were generated, and assembled into 98,796 unique transcripts. We identified 3,905 differentially expressed genes implicated in leaf development, 67.8% (2,651) of which were during the transition to leaf maturation. The genes involved in cyanogenic metabolism, lignin and anthocyanin biosynthesis were noteworthy for their distinct patterns of expression between developing leaves (stages I to III) and mature leaves (stage IV), and the correlation with the change in resistance to SALB and the Oidium/Colletotrichum leaf fall. The results provide a first profile of the molecular events that relate to the dynamics of leaf morphology and defense strategies during Hevea leaf development. This dataset is beneficial to devising strategies to engineer resistance to leaf diseases as well as other in-depth studies in Hevea tree. PMID:27619402

  16. Evaluation of hydroxyapatite-bioglass and hydroxyapatite-ethyl vinyl acetate composite extracts on antioxidant defense mechanism and genotoxicity: an in vitro study.

    PubMed

    Arun, M; Silja, P K; Mohanan, P V

    2011-09-01

    Hydroxyapatite-bioglass (HA BG) and hydroxyapatite-ethyl vinyl acetate (HA EVA) are two composite materials that have been developed for bone substitution. Their activity on antioxidant defense mechanism and genotoxicity has not been investigated before. To further confirm its biocompatibility, the present study was undertaken to investigate the effect of HA BG and HA EVA on mice liver antioxidant mechanism along with chromosomal aberrations in human lymphocytes. Physiological saline extract of HA BG and HA EVA showed no adverse effect on liver antioxidant mechanism compared to the cyclophosphamide (CP)-induced toxicity on mice liver homogenate. The results were judged from the in vitro studies made on reduced glutathione, glutathione reductase and lipid peroxidation. These results were well supported by CP- and mytomycin C (MC)-induced genotoxicity studies on human lymphocytes in the presence and absence of a metabolic activator (S9). Hence, it was suggested that these tests could be considered for preliminary toxicological screening of materials intended for clinical applications ahead of in vivo animal model evaluation.

  17. Detection of neural activity in the brains of Japanese honeybee workers during the formation of a "hot defensive bee ball".

    PubMed

    Ugajin, Atsushi; Kiya, Taketoshi; Kunieda, Takekazu; Ono, Masato; Yoshida, Tadaharu; Kubo, Takeo

    2012-01-01

    Anti-predator behaviors are essential to survival for most animals. The neural bases of such behaviors, however, remain largely unknown. Although honeybees commonly use their stingers to counterattack predators, the Japanese honeybee (Apis cerana japonica) uses a different strategy to fight against the giant hornet (Vespa mandarinia japonica). Instead of stinging the hornet, Japanese honeybees form a "hot defensive bee ball" by surrounding the hornet en masse, killing it with heat. The European honeybee (A. mellifera ligustica), on the other hand, does not exhibit this behavior, and their colonies are often destroyed by a hornet attack. In the present study, we attempted to analyze the neural basis of this behavior by mapping the active brain regions of Japanese honeybee workers during the formation of a hot defensive bee ball. First, we identified an A. cerana homolog (Acks = Apis cerana kakusei) of kakusei, an immediate early gene that we previously identified from A. mellifera, and showed that Acks has characteristics similar to kakusei and can be used to visualize active brain regions in A. cerana. Using Acks as a neural activity marker, we demonstrated that neural activity in the mushroom bodies, especially in Class II Kenyon cells, one subtype of mushroom body intrinsic neurons, and a restricted area between the dorsal lobes and the optic lobes was increased in the brains of Japanese honeybee workers involved in the formation of a hot defensive bee ball. In addition, workers exposed to 46°C heat also exhibited Acks expression patterns similar to those observed in the brains of workers involved in the formation of a hot defensive bee ball, suggesting that the neural activity observed in the brains of workers involved in the hot defensive bee ball mainly reflects thermal stimuli processing.

  18. Defensive behaviour and biological activities of the abdominal secretion in the ant Crematogaster scutellaris (Hymenoptera: Myrmicinae).

    PubMed

    Marlier, J F; Quinet, Y; de Biseau, J C

    2004-11-30

    Using bioassays, the defensive behaviour of Crematogaster scutellaris and the biological activities of its abdominal secretion were investigated. Beside classical aggressive behaviours such as grips, C. scutellaris workers performed frequent characteristic gaster flexions during interspecific encounters, sometimes tempting to apply their abdominal secretion topically on the enemy. The toxicity of the venom of C. scutellaris to other ants greatly differed among the species tested, some being killed after the topical application of only three droplets, while others were quite resistant to a dose of 90 droplets. All ant species tested were strongly and immediately repelled by a contact between their antennae or mouthparts with the venom of C. scutellaris. Abdominal secretion was never used during intraspecific interference and workers were resistant to a topical application of the venom of their own species. Intraspecific repellency was significant but moderate compared to interspecific one. Workers of C. scutellaris were never seen using their venom during prey capture. In conclusion, the main biological activity of the abdominal secretion of C. scutellaris seems to be its repellency to other ant species. This is supported by field experiments showing that Pheidole pallidula foragers were efficiently repelled at coexploited baits, allowing the monopolization of most prey by C. scutellaris.

  19. A role for host activation-induced cytidine deaminase in innate immune defense against KSHV.

    PubMed

    Bekerman, Elena; Jeon, Diana; Ardolino, Michele; Coscoy, Laurent

    2013-01-01

    Activation-induced cytidine deaminase (AID) is specifically induced in germinal center B cells to carry out somatic hypermutation and class-switch recombination, two processes responsible for antibody diversification. Because of its mutagenic potential, AID expression and activity are tightly regulated to minimize unwanted DNA damage. Surprisingly, AID expression has been observed ectopically during pathogenic infections. However, the function of AID outside of the germinal centers remains largely uncharacterized. In this study, we demonstrate that infection of human primary naïve B cells with Kaposi's sarcoma-associated herpesvirus (KSHV) rapidly induces AID expression in a cell intrinsic manner. We find that infected cells are marked for elimination by Natural Killer cells through upregulation of NKG2D ligands via the DNA damage pathway, a pathway triggered by AID. Moreover, without having a measurable effect on KSHV latency, AID impinges directly on the viral fitness by inhibiting lytic reactivation and reducing infectivity of KSHV virions. Importantly, we uncover two KSHV-encoded microRNAs that directly regulate AID abundance, further reinforcing the role for AID in the antiviral response. Together our findings reveal additional functions for AID in innate immune defense against KSHV with implications for a broader involvement in innate immunity to other pathogens.

  20. Dynamics of single unit activity in the association cortex of waking cats during defensive conditioning.

    PubMed

    Shevko, G N; Bakanova, N F

    1981-01-01

    Responses of neurons in association area 5 during defensive conditioning to acoustic stimulation were studied in chronic experiments on cats. As a rule the neurons responded by excitation to presentation of conditioned and unconditioned stimuli. During the conditioned reflex unit responses usually appeared in the first 50 msec after the beginning of acoustic stimulation, i.e., they were connected with the action of the conditioned stimulus and not with manifestations of conditioned-reflex motion. The most significant changes in responses of cortical association units were observed in the initial period of conditioning. During stabilization of the conditioned reflex, responses of some neurons became stabilized, whereas in other neurons the spontaneous activity and intensity of responses increased, and in a third group the response to one of the stimuli disappeared. This last result indicated a switch during conditioning from polysensory unit responses to monosensory specialized responses. Extinctive inhibition was found to consist of a gradual decrease in the level of the spike discharge and its approximation to spontaneous activity, i.e., to be passive in character.

  1. Intracellular oxidant activity, antioxidant enzyme defense system, and cell senescence in fibroblasts with trisomy 21.

    PubMed

    Rodríguez-Sureda, Víctor; Vilches, Ángel; Sánchez, Olga; Audí, Laura; Domínguez, Carmen

    2015-01-01

    Down's syndrome (DS) is characterized by a complex phenotype associated with chronic oxidative stress and mitochondrial dysfunction. Overexpression of genes on chromosome-21 is thought to underlie the pathogenesis of the major phenotypic features of DS, such as premature aging. Using cultured fibroblasts with trisomy 21 (T21F), this study aimed to ascertain whether an imbalance exists in activities, mRNA, and protein expression of the antioxidant enzymes SOD1, SOD2, glutathione-peroxidase, and catalase during the cell replication process in vitro. T21F had high SOD1 expression and activity which led to an interenzymatic imbalance in the antioxidant defense system, accentuated with replicative senescence. Intracellular ROS production and oxidized protein levels were significantly higher in T21F compared with control cells; furthermore, a significant decline in intracellular ATP content was detected in T21F. Cell senescence was found to appear prematurely in DS cells as shown by SA-β-Gal assay and p21 assessment, though not apoptosis, as neither p53 nor the proapoptotic proteins cytochrome c and caspase 9 were altered in T21F. These novel findings would point to a deleterious role of oxidatively modified molecules in early cell senescence of T21F, thereby linking replicative and stress-induced senescence in cultured cells to premature aging in DS.

  2. Potential fluid mechanic pathways of platelet activation.

    PubMed

    Shadden, Shawn C; Hendabadi, Sahar

    2013-06-01

    Platelet activation is a precursor for blood clotting, which plays leading roles in many vascular complications and causes of death. Platelets can be activated by chemical or mechanical stimuli. Mechanically, platelet activation has been shown to be a function of elevated shear stress and exposure time. These contributions can be combined by considering the cumulative stress or strain on a platelet as it is transported. Here, we develop a framework for computing a hemodynamic-based activation potential that is derived from a Lagrangian integral of strain rate magnitude. We demonstrate that such a measure is generally maximized along, and near to, distinguished material surfaces in the flow. The connections between activation potential and these structures are illustrated through stenotic flow computations. We uncover two distinct structures that may explain observed thrombus formation at the apex and downstream of stenoses. More broadly, these findings suggest fundamental relationships may exist between potential fluid mechanic pathways for mechanical platelet activation and the mechanisms governing their transport.

  3. Nonthermal activation of transient receptor potential vanilloid-1 channels in abdominal viscera tonically inhibits autonomic cold-defense effectors.

    PubMed

    Steiner, Alexandre A; Turek, Victoria F; Almeida, Maria C; Burmeister, Jeffrey J; Oliveira, Daniela L; Roberts, Jennifer L; Bannon, Anthony W; Norman, Mark H; Louis, Jean-Claude; Treanor, James J S; Gavva, Narender R; Romanovsky, Andrej A

    2007-07-11

    An involvement of the transient receptor potential vanilloid (TRPV) 1 channel in the regulation of body temperature (T(b)) has not been established decisively. To provide decisive evidence for such an involvement and determine its mechanisms were the aims of the present study. We synthesized a new TRPV1 antagonist, AMG0347 [(E)-N-(7-hydroxy-5,6,7,8-tetrahydronaphthalen-1-yl)-3-(2-(piperidin-1-yl)-6-(trifluoromethyl)pyridin-3-yl)acrylamide], and characterized it in vitro. We then found that this drug is the most potent TRPV1 antagonist known to increase T(b) of rats and mice and showed (by using knock-out mice) that the entire hyperthermic effect of AMG0347 is TRPV1 dependent. AMG0347-induced hyperthermia was brought about by one or both of the two major autonomic cold-defense effector mechanisms (tail-skin vasoconstriction and/or thermogenesis), but it did not involve warmth-seeking behavior. The magnitude of the hyperthermic response depended on neither T(b) nor tail-skin temperature at the time of AMG0347 administration, thus indicating that AMG0347-induced hyperthermia results from blockade of tonic TRPV1 activation by nonthermal factors. AMG0347 was no more effective in causing hyperthermia when administered into the brain (intracerebroventricularly) or spinal cord (intrathecally) than when given systemically (intravenously), which indicates a peripheral site of action. We then established that localized intra-abdominal desensitization of TRPV1 channels with intraperitoneal resiniferatoxin blocks the T(b) response to systemic AMG0347; the extent of desensitization was determined by using a comprehensive battery of functional tests. We conclude that tonic activation of TRPV1 channels in the abdominal viscera by yet unidentified nonthermal factors inhibits skin vasoconstriction and thermogenesis, thus having a suppressive effect on T(b).

  4. Seasonal Variations of the Activity of Antioxidant Defense Enzymes in the Red Mullet (Mullus barbatus l.) from the Adriatic Sea

    PubMed Central

    Pavlović, Sladjan Z.; Borković Mitić, Slavica S.; Radovanović, Tijana B.; Perendija, Branka R.; Despotović, Svetlana G.; Gavrić, Jelena P.; Saičić, Zorica S.

    2010-01-01

    This study investigated seasonal variations of antioxidant defense enzyme activities: total, manganese, copper zinc containing superoxide dismutase (Tot SOD, Mn SOD, CuZn SOD), catalase (CAT), glutathione peroxidase (GSH-Px), glutathione reductase (GR) and biotransformation phase II enzyme glutathione-S-transferase (GST) activity in the liver and white muscle of red mullet (Mullus barbatus). The investigations were performed in winter and spring at two localities: Near Bar (NB) and Estuary of the River Bojana (EB) in the Southern Adriatic Sea. At both sites, Mn SOD, GSH-Px, GR and GST activities decreased in the liver in spring. In the white muscle, activities of Mn SOD, GSH-Px, GR and GST in NB decreased in spring. GR decreased in spring in EB, while CAT activity was higher in spring at both sites. The results of Principal Component Analysis (PCA) based on correlations indicated a clear separation of various sampling periods for both investigated tissues and a marked difference between two seasons. Our study is the first report on antioxidant defense enzyme activities in the red mullet in the Southern Adriatic Sea. It indicates that seasonal variations of antioxidant defense enzyme activities should be used in further biomonitoring studies in fish species. PMID:20411106

  5. Seasonal variations of the activity of antioxidant defense enzymes in the red mullet (Mullus barbatus l.) from the Adriatic Sea.

    PubMed

    Pavlović, Sladjan Z; Borković Mitić, Slavica S; Radovanović, Tijana B; Perendija, Branka R; Despotović, Svetlana G; Gavrić, Jelena P; Saicić, Zorica S

    2010-02-26

    This study investigated seasonal variations of antioxidant defense enzyme activities: total, manganese, copper zinc containing superoxide dismutase (Tot SOD, Mn SOD, CuZn SOD), catalase (CAT), glutathione peroxidase (GSH-Px), glutathione reductase (GR) and biotransformation phase II enzyme glutathione-S-transferase (GST) activity in the liver and white muscle of red mullet (Mullus barbatus). The investigations were performed in winter and spring at two localities: Near Bar (NB) and Estuary of the River Bojana (EB) in the Southern Adriatic Sea. At both sites, Mn SOD, GSH-Px, GR and GST activities decreased in the liver in spring. In the white muscle, activities of Mn SOD, GSH-Px, GR and GST in NB decreased in spring. GR decreased in spring in EB, while CAT activity was higher in spring at both sites. The results of Principal Component Analysis (PCA) based on correlations indicated a clear separation of various sampling periods for both investigated tissues and a marked difference between two seasons. Our study is the first report on antioxidant defense enzyme activities in the red mullet in the Southern Adriatic Sea. It indicates that seasonal variations of antioxidant defense enzyme activities should be used in further biomonitoring studies in fish species.

  6. Annual Report To Congress. Department of Energy Activities Relating to the Defense Nuclear Facilities Safety Board, Calendar Year 2003

    SciTech Connect

    None, None

    2004-02-28

    The Department of Energy (Department) submits an Annual Report to Congress each year detailing the Department’s activities relating to the Defense Nuclear Facilities Safety Board (Board), which provides advice and recommendations to the Secretary of Energy (Secretary) regarding public health and safety issues at the Department’s defense nuclear facilities. In 2003, the Department continued ongoing activities to resolve issues identified by the Board in formal recommendations and correspondence, staff issue reports pertaining to Department facilities, and public meetings and briefings. Additionally, the Department is implementing several key safety initiatives to address and prevent safety issues: safety culture and review of the Columbia accident investigation; risk reduction through stabilization of excess nuclear materials; the Facility Representative Program; independent oversight and performance assurance; the Federal Technical Capability Program (FTCP); executive safety initiatives; and quality assurance activities. The following summarizes the key activities addressed in this Annual Report.

  7. Brain activation and defensive response mobilization during sustained exposure to phobia-related and other affective pictures in spider phobia.

    PubMed

    Wendt, Julia; Lotze, Martin; Weike, Almut I; Hosten, Norbert; Hamm, Alfons O

    2008-03-01

    This study explored defensive response mobilization as well as fMRI responses during sustained exposure to phobia-relevant stimuli. To test the specificity of affective physiology and brain activation, neutral and other affective stimuli were included. Phobia-specific startle potentiation was maintained and autonomic responses even increased during sustained phobic stimulation. Viewing of spider pictures also resulted in increased activation of the amygdala in spider-phobic participants. This effect, however, was not fear specific because other affective materials evoked comparable signal strength in the amygdala. In contrast, insula activation was specifically increased during sustained phobic exposure in phobic volunteers. These data suggest that the activation of the amygdala in fMRI studies primarily indexes the detection of motivationally relevant stimuli whereas the insula might be more specifically linked to defensive response mobilization.

  8. Reactive Oxygen and Nitrogen Species in Defense/Stress Responses Activated by Chitosan in Sycamore Cultured Cells

    PubMed Central

    Malerba, Massimo; Cerana, Raffaella

    2015-01-01

    Chitosan (CHT) is a non-toxic and inexpensive compound obtained by deacetylation of chitin, the main component of the exoskeleton of arthropods as well as of the cell walls of many fungi. In agriculture CHT is used to control numerous diseases on various horticultural commodities but, although different mechanisms have been proposed, the exact mode of action of CHT is still unknown. In sycamore (Acer pseudoplatanus L.) cultured cells, CHT induces a set of defense/stress responses that includes production of H2O2 and nitric oxide (NO). We investigated the possible signaling role of these reactive molecules in some CHT-induced responses by means of inhibitors of production and/or scavengers. The results show that both reactive nitrogen and oxygen species are not only a mere symptom of stress conditions but are involved in the responses induced by CHT in sycamore cells. In particular, NO appears to be involved in a cell death form induced by CHT that shows apoptotic features like DNA fragmentation, increase in caspase-3-like activity and release of cytochrome c from the mitochondrion. On the contrary, reactive oxygen species (ROS) appear involved in a cell death form induced by CHT that does not show these apoptotic features but presents increase in lipid peroxidation. PMID:25642757

  9. Do pathogen-specific defense mechanisms contribute to wound-induced resistance in tomato?

    PubMed Central

    Francia, Doriana; Demaria, Daniele; Calderini, Ornella; Ferraris, Lucia; Valentino, Danila; Arcioni, Sergio; Tamietti, Giacomo

    2008-01-01

    A network of shared intermediates/components and/or common molecular outputs in biotic and abiotic stress signaling has long been known, but the possibility of effective influence between differently triggered stresses (co-protection) is less studied. Recent observations show that wounding induces transient protection in tomato (Solanum lycopersicum L.) to four pathogens with a range of lifestyles, locally and systemically. The contribution of ethylene (ET) in basal but also in wound-induced resistance to each pathogen, although dispensable, is demonstrated to be positive (Botrytis cinerea, Phytophthora capsici) or negative (Fusarium oxysporum, Pseudomonas syringae pv. tomato). Furthermore, the expression of several defense markers is influenced locally and/or systemically by wounding and ET, and might be part of that core of conserved molecular responses whereby an abiotic stress such as wounding imparts co-resistance to biotic stress. In this addendum, we speculate on some of the physiological responses to wounding that might contribute to the modulation of resistance in a more pathogen-specific manner. PMID:19841665

  10. beta-cell apoptosis and defense mechanisms: lessons from type 1 diabetes.

    PubMed

    Eizirik, D L; Darville, M I

    2001-02-01

    Increased evidence suggests that apoptosis is the main mode of beta-cell death in early type 1 diabetes. Cytokines mediate beta-cell apoptosis, and in this article, we discuss some of the cytokine-modified genes that may contribute to beta-cell survival or death. The gene encoding for the inducible form of nitric oxide synthase is induced by interleukin (IL)-1beta or IL-1beta plus gamma-interferon in rodent and human islets, respectively. This leads to nitric oxide (NO) formation, which contributes to a major extent to beta-cell necrosis and to a minor extent to the process of beta-cell apoptosis. The main mode of cell death induced by cytokines in human beta-cells is apoptosis, whereas cytokines lead to both necrosis and apoptosis in rat and mouse beta-cells. It is suggested that the necrotic component in rodent islets is due to NO-induced mitochondrial impairment and consequent decreased ATP production. Human islets, possessing better antioxidant defenses, are able to preserve glucose oxidation and ATP production, and can thus complete the apoptotic program after the death signal delivered by cytokines. We propose that this death signal results from cytokine-induced parallel and/or sequential changes in the expression of multiple proapoptotic and prosurvival genes. The identity of these "gene modules" and of the transcription factors regulating them remains to be established.

  11. Sulfur volatiles in guava (Psidium guajava L.) leaves: possible defense mechanism.

    PubMed

    Rouseff, Russell L; Onagbola, Ebenezer O; Smoot, John M; Stelinski, Lukasz L

    2008-10-08

    Volatiles from crushed and intact guava leaves (Psidium guajava L.) were collected using static headspace SPME and determined using GC-PFPD, pulsed flame photometric detection, and GC-MS. Leaf volatiles from four common citrus culitvars were examined similarly to determine the potential component(s) responsible for guava's protective effect against the Asian citrus psyllid (Diaphorina citri Kuwayama), which is the insect vector of Huanglongbing (HLB) or citrus greening disease. Seven sulfur volatiles were detected: hydrogen sulfide, sulfur dioxide, methanethiol, dimethyl sulfide (DMS), dimethyl disulfide (DMDS), methional, and dimethyl trisulfide (DMTS). Identifications were based on matching linear retention index values on ZB-5, DB-Wax, and PLOT columns and MS spectra in the case of DMDS and DMS. DMDS is an insect toxic, defensive volatile produced only by wounded guava but not citrus leaves and, thus, may be the component responsible for the protective effect of guava against the HLB vector. DMDS is formed immediately after crushing, becoming the major headspace volatile within 10 min. Forty-seven additional leaf volatiles were identified from LRI and MS data in the crushed guava leaf headspace.

  12. Simultaneous generation of methane, carbon dioxide, and carbon monoxide from choline and ascorbic acid: a defensive mechanism against reductive stress?

    PubMed

    Ghyczy, Miklós; Torday, Csilla; Boros, Mihály

    2003-06-01

    Indirect evidence suggests that an abnormal increase in reducing power (reductive stress) may be associated with abnormal clinical states. We have recently proposed that under such conditions biomolecules with electrophilic methyl groups (EMGs) bound to positively charged nitrogen or sulfur moieties may act as electron acceptors and that this poising mechanism may entail the generation of methane gas. Here we report for the first time the generation of methane by rat liver mitochondria. We also report the formation of methane from choline in the presence of hydrogen peroxide, catalytic iron, and ascorbic acid. In this system, carbon monoxide and carbon dioxide are formed from the ascorbate molecule in parallel with methane generation. In view of these findings, we try to explain the essential role of biomolecules with EMG moiety. We hypothesize that this concerted reaction may be a defensive response to reductive stress and may provide the protection needed against redox imbalance in living systems.

  13. Priming for JA-dependent defenses using hexanoic acid is an effective mechanism to protect Arabidopsis against B. cinerea.

    PubMed

    Kravchuk, Zhana; Vicedo, Begonya; Flors, Víctor; Camañes, Gemma; González-Bosch, Carmen; García-Agustín, Pilar

    2011-03-01

    Soil drench treatments with hexanoic acid can effectively protect Arabidopsis plants against Botrytis cinerea through a mechanism based on a stronger and faster accumulation of JA-dependent defenses. Plants impaired in ethylene, salicylic acid, abscisic acid or glutathion pathways showed intact protection by hexanoic acid upon B. cinerea infection. Accordingly, no significant changes in the SA marker gene PR-1 in either the SA or ABA hormone balance were observed in the infected and treated plants. In contrast, the JA signaling pathway showed dramatic changes after hexanoic acid treatment, mainly when the pathogen was present. The impaired JA mutants, jin1-2 and jar1, were unable to display hexanoic acid priming against the necrotroph. In addition, hexanoic acid-treated plants infected with B. cinerea showed priming in the expression of the PDF1.2, PR-4 and VSP1 genes implicated in the JA pathways. Moreover, JA and OPDA levels were primed at early stages by hexanoic acid. Treatments also stimulated increased callose accumulation in response to the pathogen. Although callose accumulation has proved an effective IR mechanism against B. cinerea, it is apparently not essential to express hexanoic acid-induced resistance (HxAc-IR) because the mutant pmr4.1 (callose synthesis defective mutant) is protected by treatment. We recently described how hexanoic acid treatments can protect tomato plants against B. cinerea by stimulating ABA-dependent callose deposition and by priming OPDA and JA-Ile production. We clearly demonstrate here that Hx-IR is a dependent plant species, since this acid protects Arabidopsis plants against the same necrotroph by priming JA-dependent defenses without enhancing callose accumulation.

  14. Modeling and Implementation of Solder-activated Joints for Single Actuator, Centimeter-Scale Robotic Mechanisms

    DTIC Science & Technology

    2010-06-01

    mechanisms may be built and actuated to perform a multiplicity of tasks using PCM-activated joints. The robot was developed under the Chemical Robots DARPA ...components. 4.1.1 Chemical Robots Program The Chemical Robots (ChemBots) program is funded by the DARPA Defense Sciences Office. The goal of the program...perform tasks in these hostile and hard to reach spaces safely, covertly, and efficiently [26]. To develop this new class of robots, DARPA asked for

  15. Cytokinins act synergistically with salicylic acid to activate defense gene expression in rice.

    PubMed

    Jiang, Chang-Jie; Shimono, Masaki; Sugano, Shoji; Kojima, Mikiko; Liu, Xinqiong; Inoue, Haruhiko; Sakakibara, Hitoshi; Takatsuji, Hiroshi

    2013-03-01

    Hormone crosstalk is pivotal in plant-pathogen interactions. Here, we report on the accumulation of cytokinins (CK) in rice seedlings after infection of blast fungus Magnaporthe oryzae and its potential significance in rice-M. oryzae interaction. Blast infection to rice seedlings increased levels of N(6)-(Δ(2)-isopentenyl) adenine (iP), iP riboside (iPR), and iPR 5'-phosphates (iPRP) in leaf blades. Consistent with this, CK signaling was activated around the infection sites, as shown by histochemical staining for β-glucuronidase activity driven by a CK-responsive OsRR6 promoter. Diverse CK species were also detected in the hyphae (mycelium), conidia, and culture filtrates of blast fungus, indicating that M. oryzae is capable of production as well as hyphal secretion of CK. Co-treatment of leaf blades with CK and salicylic acid (SA), but not with either one alone, markedly induced pathogenesis-related genes OsPR1b and probenazole-induced protein 1 (PBZ1). These effects were diminished by RNAi-knockdown of OsNPR1 or WRKY45, the key regulators of the SA signaling pathway in rice, indicating that the effects of CK depend on these two regulators. Taken together, our data imply a coevolutionary rice-M. oryzae interaction, wherein M. oryzae probably elevates rice CK levels for its own benefits such as nutrient translocation. Rice plants, on the other hand, sense it as an infection signal and activate defense reactions through the synergistic action with SA.

  16. Sulforaphane protects Microcystin-LR-induced toxicity through activation of the Nrf2-mediated defensive response

    SciTech Connect

    Gan Nanqin; Mi Lixin; Sun Xiaoyun; Dai Guofei; Chung Funglung; Song Lirong

    2010-09-01

    Microcystins (MCs), a cyclic heptapeptide hepatotoxins, are mainly produced by the bloom-forming cyanobacerium Microcystis, which has become an environmental hazard worldwide. Long term consumption of MC-contaminated water may induce liver damage, liver cancer, and even human death. Therefore, in addition to removal of MCs in drinking water, novel strategies that prevent health damages are urgently needed. Sulforaphane (SFN), a natural-occurring isothiocyanate from cruciferous vegetables, has been reported to reduce and eliminate toxicities from xenobiotics and carcinogens. The purpose of the present study was to provide mechanistic insights into the SFN-induced antioxidative defense system against MC-LR-induced cytotoxicity. We performed cell viability assays, including MTS assay, colony formation assay and apoptotic cell sorting, to study MC-LR-induced cellular damage and the protective effects by SFN. The results showed that SFN protected MC-LR-induced damages at a nontoxic and physiological relevant dose in HepG2, BRL-3A and NIH 3 T3 cells. The protection was Nrf2-mediated as evident by transactivation of Nrf2 and activation of its downstream genes, including NQO1 and HO-1, and elevated intracellular GSH level. Results of our studies indicate that pretreatment of cells with 10 {mu}M SFN for 12 h significantly protected cells from MC-LR-induced damage. SFN-induced protective response was mediated through Nrf2 pathway.

  17. Chitosan controls postharvest anthracnose in bell pepper by activating defense-related enzymes.

    PubMed

    Edirisinghe, Madushani; Ali, Asgar; Maqbool, Mehdi; Alderson, Peter G

    2014-12-01

    Anthracnose, a postharvest disease caused by the fungus Colletotrichum capsici is the most devastating disease of bell pepper that causes great economic losses especially in tropical climates. Therefore, the objective of this study was to evaluate the antifungal properties of chitosan (low molecular weight from crab shell, Mw: 50 kDa and 75-85 % deacetylated) against anthracnose by inducing defense-related enzymes. The concentrations of 0, 0.5, 1.0, 1.5 and 2.0 % chitosan were used to control the fungus in vitro and postharvest. There was a reduction in C. capsici mycelial growth and the highest chitosan concentration (2.0 %) reduced the growth by 70 % after 7 days incubation. In germination test, the concentration of 1.5 and 2.0 % chitosan reduced spore germination in C. capsici between 80 % and 84 %, respectively. In postharvest trial the concentration of 1.5 % decreased the anthracnose severity in pepper fruit by approximately 76 % after 28 days of storage (10 ± 1 °C; 80 % RH). For enzymatic activities, the concentration of 1.5 and 2.0 % chitosan increased the polyphenol oxidase (PPO), peroxidase (POD) and total phenolics in inoculated bell pepper during storage. Based on these results, the chitosan presents antifungal properties against C. capsici, as well as potential to induce resistance on bell pepper.

  18. Interaction between two rice mitogen activated protein kinases and its possible role in plant defense

    PubMed Central

    2013-01-01

    Background The canonical mitogen activated protein kinase (MAPK) signaling pathway plays a vital role in carrying out the normal growth and development of the plant. The pathway, connecting the upstreams signal with the downstream target is considered to be linear, mostly starting with a MAPKKK and ending in a MAPK. Results Here we report a novel interaction between two rice MAPKs, OsMPK20-4 and OsMPK3 suggesting the complex nature of the pathway rather than a linear one at individual steps. The interaction between OsMPK20-4 and OsMPK3 found by yeast two-hybrid analysis was confirmed in planta by co-immunoprecipitation and fluorescence resonance energy transfer (FRET) assays. The interaction is specific and is phosphorylation independent. The results suggest a role of the interaction between OsMPK20-4 and OsMPK3 in basic plant defense. Conclusions The current novel work showing the physical interaction between two plant MAPKs, OsMPK20-4 and OsMPK3 is the diversion from the dogma of a typical MAPK cascade thereby opening a new dimension to the MAPK signal transduction. PMID:23984709

  19. Involvement of Trichoderma Trichothecenes in the Biocontrol Activity and Induction of Plant Defense-Related Genes

    PubMed Central

    Malmierca, M. G.; Cardoza, R. E.; Alexander, N. J.; McCormick, S. P.; Hermosa, R.; Monte, E.

    2012-01-01

    Trichoderma species produce trichothecenes, most notably trichodermin and harzianum A (HA), by a biosynthetic pathway in which several of the involved proteins have significant differences in functionality compared to their Fusarium orthologues. In addition, the genes encoding these proteins show a genomic organization differing from that of the Fusarium tri clusters. Here we describe the isolation of Trichoderma arundinaceum IBT 40837 transformants which have a disrupted or silenced tri4 gene, a gene encoding a cytochrome P450 monooxygenase that oxygenates trichodiene to give rise to isotrichodiol, and the effect of tri4 gene disruption and silencing on the expression of other tri genes. Our results indicate that the tri4 gene disruption resulted in a reduced antifungal activity against Botrytis cinerea and Rhizoctonia solani and also in a reduced ability to induce the expression of tomato plant defense-related genes belonging to the salicylic acid (SA) and jasmonate (JA) pathways against B. cinerea, in comparison to the wild-type strain, indicating that HA plays an important function in the sensitization of Trichoderma-pretreated plants against this fungal pathogen. Additionally, the effect of the interaction of T. arundinaceum with B. cinerea or R. solani and with tomato seedlings on the expressions of the tri genes was studied. PMID:22562989

  20. A Novel Topology Link-Controlling Approach for Active Defense of a Node in a Network.

    PubMed

    Li, Jun; Hu, HanPing; Ke, Qiao; Xiong, Naixue

    2017-03-09

    With the rapid development of virtual machine technology and cloud computing, distributed denial of service (DDoS) attacks, or some peak traffic, poses a great threat to the security of the network. In this paper, a novel topology link control technique and mitigation attacks in real-time environments is proposed. Firstly, a non-invasive method of deploying virtual sensors in the nodes is built, which uses the resource manager of each monitored node as a sensor. Secondly, a general topology-controlling approach of resisting the tolerant invasion is proposed. In the proposed approach, a prediction model is constructed by using copula functions for predicting the peak of a resource through another resource. The result of prediction determines whether or not to initiate the active defense. Finally, a minority game with incomplete strategy is employed to suppress attack flows and improve the permeability of the normal flows. The simulation results show that the proposed approach is very effective in protecting nodes.

  1. Hydrogen peroxide activates cell death and defense gene expression in birch.

    PubMed

    Pellinen, Riikka I; Korhonen, Minna-Sisko; Tauriainen, Airi A; Palva, E Tapio; Kangasjärvi, Jaakko

    2002-10-01

    The function of hydrogen peroxide (H(2)O(2)) as a signal molecule regulating gene expression and cell death induced by external stresses was studied in birch (Betula pendula). Ozone (O(3)), Pseudomonas syringae pv syringae (Pss), and wounding all induced cell death of various extents in birch leaves. This was temporally preceded and closely accompanied by H(2)O(2) accumulation at, and especially surrounding, the lesion sites. O(3) and Pss, along with an artificial H(2)O(2) producing system glucose (Glc)/Glc oxidase, elicited elevated mRNA levels corresponding to genes encoding reactive oxygen species detoxifying enzymes, Pal, Ypr10, and mitochondrial phosphate translocator 1. In addition to the regulation of gene expression, Glc/Glc oxidase also induced endogenous H(2)O(2) production in birch leaves, accompanied by cell death that resembled O(3) and Pss damage. Wound-induced gene expression differed from that induced by O(3) and Pss. Thus, it appears that at least two separate defense pathways can be activated in birch leaves by stress factors, even though the early H(2)O(2) accumulation response is common among them all.

  2. A Novel Topology Link-Controlling Approach for Active Defense of Nodes in Networks

    PubMed Central

    Li, Jun; Hu, HanPing; Ke, Qiao; Xiong, Naixue

    2017-01-01

    With the rapid development of virtual machine technology and cloud computing, distributed denial of service (DDoS) attacks, or some peak traffic, poses a great threat to the security of the network. In this paper, a novel topology link control technique and mitigation attacks in real-time environments is proposed. Firstly, a non-invasive method of deploying virtual sensors in the nodes is built, which uses the resource manager of each monitored node as a sensor. Secondly, a general topology-controlling approach of resisting the tolerant invasion is proposed. In the proposed approach, a prediction model is constructed by using copula functions for predicting the peak of a resource through another resource. The result of prediction determines whether or not to initiate the active defense. Finally, a minority game with incomplete strategy is employed to suppress attack flows and improve the permeability of the normal flows. The simulation results show that the proposed approach is very effective in protecting nodes. PMID:28282962

  3. The evolution of defense mechanisms correlate with the explosive diversification of autodigesting Coprinellus mushrooms (Agaricales, Fungi).

    PubMed

    Nagy, László G; Házi, Judit; Szappanos, Balázs; Kocsubé, Sándor; Bálint, Balázs; Rákhely, Gábor; Vágvölgyi, Csaba; Papp, Tamás

    2012-07-01

    Bursts of diversification are known to have contributed significantly to the extant morphological and species diversity, but evidence for many of the theoretical predictions about adaptive radiations have remained contentious. Despite their tremendous diversity, patterns of evolutionary diversification and the contribution of explosive episodes in fungi are largely unknown. Here, using the genus Coprinellus (Psathyrellaceae, Agaricales) as a model, we report the first explosive fungal radiation and infer that the onset of the radiation correlates with a change from a multilayered to a much simpler defense structure on the fruiting bodies. We hypothesize that this change constitutes a key innovation, probably relaxing constraints on diversification imposed by nutritional investment into the development of protective tissues of fruiting bodies. Fossil calibration suggests that Coprinellus mushrooms radiated during the Miocene coinciding with global radiation of large grazing mammals following expansion of dry open grasslands. In addition to diversification rate-based methods, we test the hard polytomy hypothesis, by analyzing the resolvability of internal nodes of the backbone of the putative radiation using Reversible-Jump MCMC. We discuss potential applications and pitfalls of this approach as well as how biologically meaningful polytomies can be distinguished from alignment shortcomings. Our data provide insights into the nature of adaptive radiations in general by revealing a deceleration of morphological diversification through time. The dynamics of morphological diversification was approximated by obtaining the temporal distribution of state changes in discrete traits along the trees and comparing it with the tempo of lineage accumulation. We found that the number of state changes correlate with the number of lineages, even in parts of the tree with short internal branches, and peaks around the onset of the explosive radiation followed by a slowdown, most

  4. [Activation and inhibitory mechanisms of blood platelets].

    PubMed

    Suzuki-Inoue, Katsue

    2014-07-01

    Exposure of platelets to subendothelial matrices initiates physiological hemostasis and pathological thrombosis. Under high shear stress, von Willebrand factor bridges newly exposed collagen to glycoprotein (GP) Ib on platelets. This initial tethering facilitates association between the collagen receptor GPVI and collagen, which generates tyrosine kinase-dependent activation signals, followed by release of secondary mediators and integrin activation. Activated integrin can bind to their ligands including fibrinogen. The released secondary mediators, ADP and thromboxane A2, activate integrin of flowing platelets, which enables formation of platelet thrombi by binding of activated flowing platelets and adhered platelets to collagen via binding between activated aIIbbeta3 integrin and fibrinogen. Platelets also have inhibitory mechanisms, which help to prevent unwanted platelet activation in vivo.

  5. Spontaneous mechanical activity in depolarized frog ventricle

    PubMed Central

    1976-01-01

    Spontaneous mechanical activity can be produced in depolarized frog ventricle by bathing the tissue in a solution with low Na, Iow Ca, and high K+. The contractions can be inhibited by depleting the tissue of Ca first, but they are relatively insensitive to changes in either extracellular [Ca++] or [Ca++]/[Na+]2. They are terminated very rapidly by raising [Na+] to 40 mM. Local anesthetics enhance the spontaneous activity in proportion to the concentration of their free base form. These contractions occur relatively rhythmically for several hours. Since the preparation is multicellular, this suggests a mechanism for intercellular communication without change in membrane potential. PMID:822122

  6. Combined Activity of DCL2 and DCL3 Is Crucial in the Defense against Potato Spindle Tuber Viroid

    PubMed Central

    Katsarou, Konstantina; Mavrothalassiti, Eleni; Dermauw, Wannes; Van Leeuwen, Thomas; Kalantidis, Kriton

    2016-01-01

    Viroids are self replicating non-coding RNAs capable of infecting a wide range of plant hosts. They do not encode any proteins, thus the mechanism by which they escape plant defenses remains unclear. RNAi silencing is a major defense mechanism against virus infections, with the four DCL proteins being principal components of the pathway. We have used Nicotiana benthamiana as a model to study Potato spindle tuber viroid infection. This viroid is a member of the Pospiviroidae family and replicates in the nucleus via an asymmetric rolling circle mechanism. We have created knock-down plants for all four DCL genes and their combinations. Previously, we showed that DCL4 has a positive effect on PSTVd infectivity since viroid levels drop when DCL4 is suppressed. Here, we show that PSTVd levels remain decreased throughout infection in DCL4 knockdown plants, and that simultaneous knockdown of DCL1, DCL2 or DCL3 together with DCL4 cannot reverse this effect. Through infection of plants suppressed for multiple DCLs we further show that a combined suppression of DCL2 and DCL3 has a major effect in succumbing plant antiviral defense. Based on our results, we further suggest that Pospoviroids may have evolved to be primarily processed by DCL4 as it seems to be a DCL protein with less detrimental effects on viroid infectivity. These findings pave the way to delineate the complexity of the relationship between viroids and plant RNA silencing response. PMID:27732664

  7. Attachment, penetration and early host defense mechanisms during the infection of filamentous brown algae by Eurychasma dicksonii.

    PubMed

    Tsirigoti, Amerssa; Beakes, Gordon W; Hervé, Cécile; Gachon, Claire M M; Katsaros, Christos

    2015-05-01

    Eurychasma dicksonii is one of the most common and widespread marine pathogens and attacks a broad spectrum of more than 45 brown algal species. The present study focuses on the mechanism used by the pathogen to attach on the host cell wall and force its way into algal cells. Ultrastructural examination revealed a needle-like structure which develops within the attached spore and extends along its main axis. Particular cell wall modifications are present at the basal part of the spore (adhesorium pad) and guide the needle-like tool to penetrate perpendicularly the host cell wall. The unique injection mechanism is shared with Haptoglossa species which suggests that this is an important characteristic of early diverging oomycetes. Furthermore, the encystment and adhesion mechanism of E. dicksonii shows significant similarities with other oomycetes, some of which are plant pathogens. Staining and immunolabelling techniques showed the deposition of β-1,3-glucans on the host cell wall at the pathogen penetration site, a strategy similar to physical responses previously described only in infected plant cells. It is assumed that the host defense in terms of callose-like deposition is an ancient response to infection.

  8. Complement System Part I – Molecular Mechanisms of Activation and Regulation

    PubMed Central

    Merle, Nicolas S.; Church, Sarah Elizabeth; Fremeaux-Bacchi, Veronique; Roumenina, Lubka T.

    2015-01-01

    Complement is a complex innate immune surveillance system, playing a key role in defense against pathogens and in host homeostasis. The complement system is initiated by conformational changes in recognition molecular complexes upon sensing danger signals. The subsequent cascade of enzymatic reactions is tightly regulated to assure that complement is activated only at specific locations requiring defense against pathogens, thus avoiding host tissue damage. Here, we discuss the recent advances describing the molecular and structural basis of activation and regulation of the complement pathways and their implication on physiology and pathology. This article will review the mechanisms of activation of alternative, classical, and lectin pathways, the formation of C3 and C5 convertases, the action of anaphylatoxins, and the membrane-attack-complex. We will also discuss the importance of structure–function relationships using the example of atypical hemolytic uremic syndrome. Lastly, we will discuss the development and benefits of therapies using complement inhibitors. PMID:26082779

  9. Defense activation triggers differential expression of phospholipase-C (PLC) genes and elevated temperature induces phosphatidic acid (PA) accumulation in tomato

    PubMed Central

    Abd-El-Haliem, Ahmed; Meijer, Harold J.G.; Tameling, Wladimir I.L.; Vossen, Jack H.; Joosten, Matthieu H.A.J.

    2012-01-01

    Recently, we provided the first genetic evidence for the requirement of tomato PLC4 and PLC6 genes in defense activation and disease resistance. The encoded enzymes were catalytically active as they were able to degrade phosphatidylinositol (PI), thereby producing diacylglycerol (DG). Here we report differential PLC gene expression following the initiation of defense signaling by the interaction between Cladosporium fulvum resistance (R) protein Cf-4 and its matching effector Avr4 in tomato hybrid seedlings that express both Cf-4 and Avr4. Furthermore, we observed that PLC3 and PLC6 gene expression is upregulated by elevated temperature in the control seedlings. This upregulation coincides with an increase in the levels of phosphatidic acid (PA) and a decrease in the levels of PI and phosphatidylinositol phosphate (PIP). The decrease in PI and PIP levels matches with the activation of PLC. In addition, the levels of the structural phospholipids phosphatidylcholine (PC), phosphatidylethanolamine (PE) and phosphatidylglycerol (PG) declined transiently during recovery after the exposure to elevated temperature., Further studies will be required to explain the mechanism causing the sustained accumulation of PA during recovery, combined with a reduction in the levels of structural phospholipids. PMID:22899083

  10. Molecular mechanisms regulating NLRP3 inflammasome activation

    PubMed Central

    Jo, Eun-Kyeong; Kim, Jin Kyung; Shin, Dong-Min; Sasakawa, Chihiro

    2016-01-01

    Inflammasomes are multi-protein signaling complexes that trigger the activation of inflammatory caspases and the maturation of interleukin-1β. Among various inflammasome complexes, the NLRP3 inflammasome is best characterized and has been linked with various human autoinflammatory and autoimmune diseases. Thus, the NLRP3 inflammasome may be a promising target for anti-inflammatory therapies. In this review, we summarize the current understanding of the mechanisms by which the NLRP3 inflammasome is activated in the cytosol. We also describe the binding partners of NLRP3 inflammasome complexes activating or inhibiting the inflammasome assembly. Our knowledge of the mechanisms regulating NLRP3 inflammasome signaling and how these influence inflammatory responses offers further insight into potential therapeutic strategies to treat inflammatory diseases associated with dysregulation of the NLRP3 inflammasome. PMID:26549800

  11. Innovations in Defense Acquisition: Asymmetric Information, Mechanism Design and Prediction Markets

    DTIC Science & Technology

    2011-02-03

    is a fair characterization to say that prediction markets may be very straightforward in basic principle , but in practice the devil is certainly in...experimental economics and game theory /mechanism design. He also has research interests in strategic and competitive dynamics, particularly applied to...School in 1988, Dr. Gates work as an economist at the Jet Propulsion Laboratory in Pasadena, CA. Dr. Gates’ research interests include game theory

  12. Reactive oxygen species and antioxidant defense mechanisms in the oral cavity: a literature review.

    PubMed

    San Miguel, Symone M; Opperman, Lynne A; Allen, Edward P; Svoboda, Kathy K H

    2011-01-01

    Through dental procedures and environment, periodontal tissues are exposed to many types of reactive oxygen species (ROS). Recently, various forms of antioxidants have been introduced as an approach to fight dental diseases and improve general gingival health. This article focuses on the classification of antioxidants and the link between oxidative stress and periodontal disease. The protective mechanisms of antioxidants and how routine dental procedures may increase ROS is discussed. The final section reviews the effect of tobacco products on gingival health and disease.

  13. Analysis of Performance-Based Service Contracting and Its Applicability to Turkey’s Defense Acquisition Activities

    DTIC Science & Technology

    2010-12-01

    ABSTRACT The purpose of this MBA professional report is to explore and analyze Performance Based Service Contracting (PBSC) and provide a clear...ANALYSIS OF PERFORMANCE BASED SERVICE CONTRACTING AND ITS APPLICABILITY TO TURKEY’S DEFENSE ACQUISITION ACTIVITIES ABSTRACT The purpose of this MBA...Policy (1998): Performance-Based Service Contracting (PBSC) emphasizes that all aspects of an acquisition be structured around the purpose of the

  14. NLRP7 and related inflammasome activating pattern recognition receptors and their function in host defense and disease.

    PubMed

    Radian, Alexander D; de Almeida, Lucia; Dorfleutner, Andrea; Stehlik, Christian

    2013-01-01

    Host defense requires the maturation and release of the pro-inflammatory cytokines interleukin (IL)-1β and IL-18 and the induction of pyroptotic cell death, which depends on the activation of inflammatory Caspases within inflammasomes by innate immune cells. Several cytosolic pattern recognition receptors (PRRs) have been implicated in this process in response to infectious and sterile agonists. Here we summarize the current knowledge on inflammasome-organizing PRRs, emphasizing the recently described NLRP7, and their implications in human disease.

  15. 9-Lipoxygenase-Derived Oxylipins Activate Brassinosteroid Signaling to Promote Cell Wall-Based Defense and Limit Pathogen Infection1

    PubMed Central

    Marcos, Ruth; Izquierdo, Yovanny; Vellosillo, Tamara; Kulasekaran, Satish; Cascón, Tomás; Hamberg, Mats; Castresana, Carmen

    2015-01-01

    The oxylipins, a large family of oxygenated lipid derivatives, regulate plant development and immunity. Two members of the 9-lipoxygenase (9-LOX) oxylipin pathway, 9-hydroxyoctadecatrienoic acid and 9-ketooctadecatrienoic acid, control root development and plant defense. Studies in Arabidopsis (Arabidopsis thaliana) using a series of 9-hydroxyoctadecatrienoic acid- and 9-ketooctadecatrienoic acid-insensitive nonresponding to oxylipins (noxy) mutants showed the importance of the cell wall as a 9-LOX-induced defense component and the participation of NOXY proteins in signaling cell wall damage. Here, we examined 9-LOX signaling using the mutants lox1lox5, which lacks 9-LOX activity, and noxy2-2, which shows oxylipin insensitivity and mitochondrial dysfunction. Mutants in brassinosteroids (BRs), a class of plant hormones necessary for normal plant growth and the control of cell wall integrity, were also analyzed. Several lines of evidence indicated that 9-LOX-derived oxylipins induce BR synthesis and signaling to activate cell wall-based responses such as callose deposition and that constitutive activation of BR signaling in bri1-EMS-suppressor 1-D (bes1-D) plants enhances this response. We found that constitutive BR signaling in bes1-D and brassinolide-resistant 1-1D (bzr1-1D) mutants conferred resistance to Pseudomonas syringae. bes1-D and bzr1-1D showed increased resistance to Golovinomyces cichoracearum, an obligate biotrophic fungus that penetrates the cell wall for successful infection, whereas susceptibility was enhanced in lox1lox5 and noxy2-2. Our results indicate a sequential action of 9-LOX and BR signaling in activating cell wall-based defense, and this response prevents pathogen infection. These results show interaction between the 9-LOX and BR pathways and help to clarify their role in modulating plant defense. PMID:26417008

  16. Application of an improved proteomics method for abundant protein cleanup: molecular and genomic mechanisms study in plant defense.

    PubMed

    Zhang, Yixiang; Gao, Peng; Xing, Zhuo; Jin, Shumei; Chen, Zhide; Liu, Lantao; Constantino, Nasie; Wang, Xinwang; Shi, Weibing; Yuan, Joshua S; Dai, Susie Y

    2013-11-01

    High abundance proteins like ribulose-1,5-bisphosphate carboxylase oxygenase (Rubisco) impose a consistent challenge for the whole proteome characterization using shot-gun proteomics. To address this challenge, we developed and evaluated Polyethyleneimine Assisted Rubisco Cleanup (PARC) as a new method by combining both abundant protein removal and fractionation. The new approach was applied to a plant insect interaction study to validate the platform and investigate mechanisms for plant defense against herbivorous insects. Our results indicated that PARC can effectively remove Rubisco, improve the protein identification, and discover almost three times more differentially regulated proteins. The significantly enhanced shot-gun proteomics performance was translated into in-depth proteomic and molecular mechanisms for plant insect interaction, where carbon re-distribution was used to play an essential role. Moreover, the transcriptomic validation also confirmed the reliability of PARC analysis. Finally, functional studies were carried out for two differentially regulated genes as revealed by PARC analysis. Insect resistance was induced by over-expressing either jacalin-like or cupin-like genes in rice. The results further highlighted that PARC can serve as an effective strategy for proteomics analysis and gene discovery.

  17. Ethanol Extract of Ganoderma lucidum Augments Cellular Anti-oxidant Defense through Activation of Nrf2/HO-1

    PubMed Central

    Lee, Yoo-hwan; Kim, Jung-hee; Song, Choon-ho; Jang, Kyung-jeon; kim, Cheol-hong; Kang, Ji- Sook; Choi, Yung-hyun

    2016-01-01

    Objectives: The mushroom Ganoderma lucidum has been widely used as a traditional herbal medicine for many years. Although several studies have focused on the anti-oxidative activity of this mushroom, the molecular mechanisms underlying its activity have not yet been clearly established. The present study investigated the cytoprotective effect of ethanol extract of Ganoderma lucidum (EGL) against oxidative stress (hydrogen peroxide, H2O2) and elucidated the underlying mechanisms in a C2C12 myoblast cell line. Methods: Oxidative stress markers were determined by using the comet assay to measure reactive oxygen species (ROS) generation and deoxyribonucleic acid (DNA) damage. Cell viability and Western blotting analyses were employed to evaluate the cellular response to EGL and H2O2 in C2C12 cells. Transfection with nuclear factor erythroid 2-related factor 2 (Nrf2)-specific small interfering ribonucleic acid (siRNA) was conducted to understand the relationship between Nrf2 expression and H2O2-induced growth inhibition. Results: The results showed that EGL effectively inhibited H2O2-induced growth and the generation of ROS. EGL markedly suppressed H2O2-induced comet-like DNA formation and phosphorylation of histone H2AX at serine 139 (p-γH2AX), a widely used marker of DNA damage, suggesting that EGL prevented H2O2-induced DNA damage. Furthermore, the EGL treatment effectively induced the expression of Nrf2, as well as heme oxygenase-1 (HO-1), with parallel phosphorylation and nuclear translocation of Nrf2 in the C2C12 myoblasts. However, zinc protoporphyrin IX, a HO-1 inhibitor, significantly abolished the protective effects of EGL against H2O2-induced accumulation of ROS and reduced cell growth. Notably, transient transfection with Nrf2-specific siRNA attenuated the cytoprotective effects and HO-1 induction by EGL, indicating that EGL induced the expression of HO-1 in an Nrf2-dependent manner. Conclusion: Collectively, these results demonstrate that EGL augments the

  18. Projected near-future CO2 levels increase activity and alter defensive behaviours in the tropical squid Idiosepius pygmaeus

    PubMed Central

    Spady, Blake L.; Watson, Sue-Ann; Chase, Tory J.; Munday, Philip L.

    2014-01-01

    ABSTRACT Carbon dioxide (CO2) levels projected to occur in the oceans by the end of this century cause a range of behavioural effects in fish, but whether other highly active marine organisms, such as cephalopods, are similarly affected is unknown. We tested the effects of projected future CO2 levels (626 and 956 µatm) on the behaviour of male two-toned pygmy squid, Idiosepius pygmaeus. Exposure to elevated CO2 increased the number of active individuals by 19–25% and increased movement (number of line-crosses) by nearly 3 times compared to squid at present-day CO2. Squid vigilance and defensive behaviours were also altered by elevated CO2 with >80% of individuals choosing jet escape responses over defensive arm postures in response to a visual startle stimulus, compared with 50% choosing jet escape responses at control CO2. In addition, more escape responses were chosen over threat behaviours in body pattern displays at elevated CO2 and individuals were more than twice as likely to use ink as a defence strategy at 956 µatm CO2, compared with controls. Increased activity could lead to adverse effects on energy budgets as well as increasing visibility to predators. A tendency to respond to a stimulus with escape behaviours could increase survival, but may also be energetically costly and could potentially lead to more chases by predators compared with individuals that use defensive postures. These results demonstrate that projected future ocean acidification affects the behaviours of a tropical squid species. PMID:25326517

  19. Response and Defense Mechanisms of Taxus chinensis Leaves Under UV-A Radiation are Revealed Using Comparative Proteomics and Metabolomics Analyses.

    PubMed

    Zheng, Wen; Komatsu, Setsuko; Zhu, Wei; Zhang, Lin; Li, Ximin; Cui, Lei; Tian, Jingkui

    2016-09-01

    Taxus chinensis var. mairei is a species endemic to south-eastern China and one of the natural sources for the anticancer medicine paclitaxel. To investigate the molecular response and defense mechanisms of T. chinensis leaves to enhanced ultraviolet-A (UV-A) radiation, gel-free/label-free and gel-based proteomics and gas chromatography-mass spectrometry (GC-MS) analyses were performed. The transmission electron microscopy results indicated damage to the chloroplast under UV-A radiation. Proteomics analyses in leaves and chloroplasts showed that photosynthesis-, glycolysis-, secondary metabolism-, stress-, and protein synthesis-, degradation- and activation-related systems were mainly changed under UV-A radiation. Forty-seven PSII proteins and six PSI proteins were identified as being changed in leaves and chloroplasts under UV-A treatment. This indicated that PSII was more sensitive to UV-A than PSI as the target of UV-A light. Enhanced glycolysis, with four glycolysis-related key enzymes increased, provided precursors for secondary metabolism. The 1-deoxy-d-xylulose-5-phosphate reductoisomerase and 4-hydroxy-3-methylbut-2-enyl diphosphate reductase were identified as being significantly increased during UV-A radiation, which resulted in paclitaxel enhancement. Additionally, mRNA expression levels of genes involved in the paclitaxel biosynthetic pathway indicated a down-regulation under UV-A irradiation and up-regulation in dark incubation. These results reveal that a short-term high dose of UV-A radiation could stimulate the plant stress defense system and paclitaxel production.

  20. Crosstalk of Signaling Mechanisms Involved in Host Defense and Symbiosis Against Microorganisms in Rice

    PubMed Central

    Akamatsu, Akira; Shimamoto, Ko; Kawano, Yoji

    2016-01-01

    Rice is one of the most important food crops, feeding about half population in the world. Rice pathogens cause enormous damage to rice production worldwide. In plant immunity research, considerable progress has recently been made in our understanding of the molecular mechanisms underlying microbe-associated molecular pattern (MAMP)-triggered immunity. Using genome sequencing and molecular techniques, a number of new MAMPs and their receptors have been identified in the past two decades. Notably, the mechanisms for chitin perception via the lysine motif (LysM) domain-containing receptor OsCERK1, as well as the mechanisms for bacterial MAMP (e.g. flg22, elf18) perception via the leucine-rich repeat (LRR) domain-containing receptors FLS2 and EFR, have been clarified in rice and Arabidopsis, respectively. In chitin signaling in rice, two direct substrates of OsCERK1, Rac/ROP GTPase guanine nucleotide exchange factor OsRacGEF1 and receptor-like cytoplasmic kinase OsRLCK185, have been identified as components of the OsCERK1 complex and are rapidly phosphorylated by OsCERK1 in response to chitin. Interestingly, OsCERK1 also participates in symbiosis with arbuscular mycorrhizal fungi (AMF) in rice and plays a role in the recognition of short-chitin molecules (CO4/5), which are symbiotic signatures included in AMF germinated spore exudates and induced by synthetic strigolactone. Thus, OsCERK1 contributes to both immunity and symbiotic responses. In this review, we describe recent studies on pathways involved in rice immunity and symbiotic signaling triggered by interactions with microorganisms. In addition, we describe recent advances in genetic engineering by using plant immune receptors and symbiotic microorganisms to enhance disease resistance of rice. PMID:27499679

  1. Protozoan-induced regulation of cycliclipopeptide biosythesis is an effective predation defense mechanism for Pseudomonas fluorescens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The grazing activity of protozoa significantly impacts the dynamics, diversification and evolution of bacterial communities in soil ecosystems. The feeding preference of protozoa is related to their inability to ingest or digest specific bacteria. Pseudomonas fluorescens strains SBW25 and SS101 used...

  2. Innovations in Defense Acquisition Auctions: Lessons Learned and Alternative Mechanism Designs

    DTIC Science & Technology

    2008-02-21

    Engines, Turbines , and Components $93,321 3 29—Engine Accessories $13,109 3 30—Mechanical Power Transmission Equipment $53,183 5 31— Bearings $9,760 1... balls . In this urn, there are α black balls and β white balls (recall that α + β = 100). An individual player (be it a buyer or seller) infers the...true number of black and white balls in the urn (the true values of α and β) from the information received from its draws (the number of black and

  3. (1)H NMR and GC-MS Based Metabolomics Reveal Defense and Detoxification Mechanism of Cucumber Plant under Nano-Cu Stress.

    PubMed

    Zhao, Lijuan; Huang, Yuxiong; Hu, Jerry; Zhou, Hongjun; Adeleye, Adeyemi S; Keller, Arturo A

    2016-02-16

    Because copper nanoparticles are being increasingly used in agriculture as pesticides, it is important to assess their potential implications for agriculture. Concerns have been raised about the bioaccumulation of nano-Cu and their toxicity to crop plants. Here, the response of cucumber plants in hydroponic culture at early development stages to two concentrations of nano-Cu (10 and 20 mg/L) was evaluated by proton nuclear magnetic resonance spectroscopy ((1)H NMR) and gas chromatography-mass spectrometry (GC-MS) based metabolomics. Changes in mineral nutrient metabolism induced by nano-Cu were determined by inductively coupled plasma-mass spectrometry (ICP-MS). Results showed that nano-Cu at both concentrations interferes with the uptake of a number of micro- and macro-nutrients, such as Na, P, S, Mo, Zn, and Fe. Metabolomics data revealed that nano-Cu at both levels triggered significant metabolic changes in cucumber leaves and root exudates. The root exudate metabolic changes revealed an active defense mechanism against nano-Cu stress: up-regulation of amino acids to sequester/exclude Cu/nano-Cu; down-regulation of citric acid to reduce the mobilization of Cu ions; ascorbic acid up-regulation to combat reactive oxygen species; and up-regulation of phenolic compounds to improve antioxidant system. Thus, we demonstrate that nontargeted (1)H NMR and GC-MS based metabolomics can successfully identify physiological responses induced by nanoparticles. Root exudates metabolomics revealed important detoxification mechanisms.

  4. Exposure of cerium oxide nanoparticles to kidney bean shows disturbance in the plant defense mechanisms.

    PubMed

    Majumdar, Sanghamitra; Peralta-Videa, Jose R; Bandyopadhyay, Susmita; Castillo-Michel, Hiram; Hernandez-Viezcas, Jose-Angel; Sahi, Shivendra; Gardea-Torresdey, Jorge L

    2014-08-15

    Overwhelming use of engineered nanoparticles demands rapid assessment of their environmental impacts. The transport of cerium oxide nanoparticles (nCeO2) in plants and their impact on cellular homeostasis as a function of exposure duration is not well understood. In this study, kidney bean plants were exposed to suspensions of ∼ 8 ± 1 nm nCeO2 (62.5 to 500 mg/L) for 15 days in hydroponic conditions. Plant parts were analyzed for cerium accumulation after one, seven, and 15 days of nCeO2 exposure. The primary indicators of stress like lipid peroxidation, antioxidant enzyme activities, total soluble protein and chlorophyll contents were studied. Cerium in tissues was localized using scanning electron microscopy and synchrotron μ-XRF mapping, and the chemical forms were identified using μ-XANES. In the root epidermis, cerium was primarily shown to exist as nCeO2, although a small fraction (12%) was biotransformed to Ce(III) compound. Cerium was found to reach the root vascular tissues and translocate to aerial parts with time. Upon prolonged exposure to 500 mg nCeO2/L, the root antioxidant enzyme activities were significantly reduced, simultaneously increasing the root soluble protein by 204%. In addition, leaf's guaiacol peroxidase activity was enhanced with nCeO2 exposure in order to maintain cellular homeostasis.

  5. Low-dose AgNPs reduce lung mechanical function and innate immune defense in the absence of cellular toxicity

    PubMed Central

    Botelho, Danielle J.; Leo, Bey Fen; Massa, Christopher B.; Sarkar, Srijata; Tetley, Terry D.; Chung, Kian Fan; Chen, Shu; Ryan, Mary P.; Porter, Alexandra E.; Zhang, Junfeng; Schwander, Stephan K.; Gow, Andrew J.

    2016-01-01

    Multiple studies have examined the direct cellular toxicity of silver nanoparticles (AgNPs). However, the lung is a complex biological system with multiple cell types and a lipid-rich surface fluid; therefore, organ level responses may not depend on direct cellular toxicity. We hypothesized that interaction with the lung lining is a critical determinant of organ level responses. Here, we have examined the effects of low dose intratracheal instillation of AgNPs (0.05 µg/g body weight) 20 and 110nm diameter in size, and functionalized with citrate or polyvinylpyrrolidone. Both size and functionalization were significant factors in particle aggregation and lipid interaction in vitro. One day post-intratracheal instillation lung function was assessed, and bronchoalveolar lavage (BAL) and lung tissue collected. There were no signs of overt inflammation. There was no change in surfactant protein-B content in the BAL but there was loss of surfactant protein-D with polyvinylpyrrolidone (PVP)-stabilized particles. Mechanical impedance data demonstrated a significant increase in pulmonary elastance as compared to control, greatest with 110nm PVP-stabilized particles. Seven days post-instillation of PVP-stabilized particles increased BAL cell counts, and reduced lung function was observed. These changes resolved by 21 days. Hence, AgNP-mediated alterations in the lung lining and mechanical function resolve by 21 days. Larger particles and PVP stabilization produce the largest disruptions. These studies demonstrate that low dose AgNPs elicit deficits in both mechanical and innate immune defense function, suggesting that organ level toxicity should be considered. PMID:26152688

  6. Low-dose AgNPs reduce lung mechanical function and innate immune defense in the absence of cellular toxicity.

    PubMed

    Botelho, Danielle J; Leo, Bey Fen; Massa, Christopher B; Sarkar, Srijata; Tetley, Terry D; Chung, Kian Fan; Chen, Shu; Ryan, Mary P; Porter, Alexandra E; Zhang, Junfeng; Schwander, Stephan K; Gow, Andrew J

    2016-01-01

    Multiple studies have examined the direct cellular toxicity of silver nanoparticles (AgNPs). However, the lung is a complex biological system with multiple cell types and a lipid-rich surface fluid; therefore, organ level responses may not depend on direct cellular toxicity. We hypothesized that interaction with the lung lining is a critical determinant of organ level responses. Here, we have examined the effects of low dose intratracheal instillation of AgNPs (0.05 μg/g body weight) 20 and 110 nm diameter in size, and functionalized with citrate or polyvinylpyrrolidone. Both size and functionalization were significant factors in particle aggregation and lipid interaction in vitro. One day post-intratracheal instillation lung function was assessed, and bronchoalveolar lavage (BAL) and lung tissue collected. There were no signs of overt inflammation. There was no change in surfactant protein-B content in the BAL but there was loss of surfactant protein-D with polyvinylpyrrolidone (PVP)-stabilized particles. Mechanical impedance data demonstrated a significant increase in pulmonary elastance as compared to control, greatest with 110 nm PVP-stabilized particles. Seven days post-instillation of PVP-stabilized particles increased BAL cell counts, and reduced lung function was observed. These changes resolved by 21 days. Hence, AgNP-mediated alterations in the lung lining and mechanical function resolve by 21 days. Larger particles and PVP stabilization produce the largest disruptions. These studies demonstrate that low dose AgNPs elicit deficits in both mechanical and innate immune defense function, suggesting that organ level toxicity should be considered.

  7. Mechanobiocatalysis: Modulating Enzymatic Activity with Mechanical Force

    DTIC Science & Technology

    2015-09-28

    displayed by enzymes and other materials. It was demonstrated that the application of forces to enzymes properly outfitted with polymers resulted in...intrinsic activities displayed by enzymes and other materials. It was demonstrated that the application of forces to enzymes properly outfitted with polymers ...of eYFP-containing polymer composites via the application of mechanical force, as well as showing that the photophysical properties displayed by

  8. Topological mechanics: from metamaterials to active matter

    NASA Astrophysics Data System (ADS)

    Vitelli, Vincenzo

    2015-03-01

    Mechanical metamaterials are artificial structures with unusual properties, such as negative Poisson ratio, bistability or tunable acoustic response, which originate in the geometry of their unit cell. At the heart of such unusual behavior is often a mechanism: a motion that does not significantly stretch or compress the links between constituent elements. When activated by motors or external fields, these soft motions become the building blocks of robots and smart materials. In this talk, we discuss topological mechanisms that possess two key properties: (i) their existence cannot be traced to a local imbalance between degrees of freedom and constraints (ii) they are robust against a wide range of structural deformations or changes in material parameters. The continuum elasticity of these mechanical structures is captured by non-linear field theories with a topological boundary term similar to topological insulators and quantum Hall systems. We present several applications of these concepts to the design and experimental realization of 2D and 3D topological structures based on linkages, origami, buckling meta-materials and lastly active media that break time-reversal symmetry.

  9. Annual report to Congress: Department of Energy activities relating to the Defense Nuclear Facilities Safety Board, Calendar Year 1999

    SciTech Connect

    2000-02-01

    This is the tenth Annual Report to the Congress describing Department of Energy activities in response to formal recommendations and other interactions with the Defense Nuclear Facilities Safety Board (Board). The Board, an independent executive-branch agency established in 1988, provides advice and recommendations to the Secretary of Energy regarding public health and safety issues at the Department's defense nuclear facilities. The Board also reviews and evaluates the content and implementation of health and safety standards, as well as other requirements, relating to the design, construction, operation, and decommissioning of the Department's defense nuclear facilities. During 1999, Departmental activities resulted in the closure of nine Board recommendations. In addition, the Department has completed all implementation plan milestones associated with three Board recommendations. One new Board recommendation was received and accepted by the Department in 1999, and a new implementation plan is being developed to address this recommendation. The Department has also made significant progress with a number of broad-based initiatives to improve safety. These include expanded implementation of integrated safety management at field sites, opening of a repository for long-term storage of transuranic wastes, and continued progress on stabilizing excess nuclear materials to achieve significant risk reduction.

  10. Annual report to Congress: Department of Energy activities relating to the Defense Nuclear Facilities Safety Board, calendar year 1998

    SciTech Connect

    1999-02-01

    This is the ninth Annual Report to the Congress describing Department of Energy (Department) activities in response to formal recommendations and other interactions with the Defense Nuclear Facilities Safety Board (Board). The Board, an independent executive-branch agency established in 1988, provides advice and recommendations to the Secretary of energy regarding public health and safety issues at the Department`s defense nuclear facilities. The Board also reviews and evaluates the content and implementation of health and safety standards, as well as other requirements, relating to the design, construction, operation, and decommissioning of the Department`s defense nuclear facilities. The locations of the major Department facilities are provided. During 1998, Departmental activities resulted in the proposed closure of one Board recommendation. In addition, the Department has completed all implementation plan milestones associated with four other Board recommendations. Two new Board recommendations were received and accepted by the Department in 1998, and two new implementation plans are being developed to address these recommendations. The Department has also made significant progress with a number of broad-based initiatives to improve safety. These include expanded implementation of integrated safety management at field sites, a renewed effort to increase the technical capabilities of the federal workforce, and a revised plan for stabilizing excess nuclear materials to achieve significant risk reduction.

  11. Prunus domestica pathogenesis-related protein-5 activates the defense response pathway and enhances the resistance to fungal infection.

    PubMed

    El-kereamy, Ashraf; El-sharkawy, Islam; Ramamoorthy, Rengasamy; Taheri, Ali; Errampalli, Deena; Kumar, Prakash; Jayasankar, Subramanian

    2011-03-23

    Pathogenesis-related protein-5 (PR-5) has been implicated in plant disease resistance and its antifungal activity has been demonstrated in some fruit species. However, their roles, especially their interactions with the other defense responses in plant cells, are still not fully understood. In this study, we have cloned and characterized a new PR-5 cDNA named PdPR5-1 from the European plum (Prunus domestica). Expression of PdPR5-1 was studied in different cultivars varying in resistance to the brown rot disease caused by the necrotrophic fungus Monilinia fructicola. In addition transgenic Arabidopsis, ectopically expressing PdPR5-1 was used to study its role in other plant defense responses after fungal infection. We show that the resistant cultivars exhibited much higher levels of transcripts than the susceptible cultivars during fruit ripening. However, significant rise in the transcript levels after infection with M. fructicola was observed in the susceptible cultivars too. Transgenic Arabidopsis plants exhibited more resistance to Alternaria brassicicola. Further, there was a significant increase in the transcripts of genes involved in the phenylpropanoid biosynthesis pathway such as phenylalanine ammonia-lyase (PAL) and phytoalexin (camalexin) pathway leading to an increase in camalexin content after fungal infection. Our results show that PdPR5-1 gene, in addition to its anti-fungal properties, has a possible role in activating other defense pathways, including phytoalexin production.

  12. Mechanically activated artificial cell by using microfluidics

    PubMed Central

    Ho, Kenneth K. Y.; Lee, Lap Man; Liu, Allen P.

    2016-01-01

    All living organisms sense mechanical forces. Engineering mechanosensitive artificial cell through bottom-up in vitro reconstitution offers a way to understand how mixtures of macromolecules assemble and organize into a complex system that responds to forces. We use stable double emulsion droplets (aqueous/oil/aqueous) to prototype mechanosensitive artificial cells. In order to demonstrate mechanosensation in artificial cells, we develop a novel microfluidic device that is capable of trapping double emulsions into designated chambers, followed by compression and aspiration in a parallel manner. The microfluidic device is fabricated using multilayer soft lithography technology, and consists of a control layer and a deformable flow channel. Deflections of the PDMS membrane above the main microfluidic flow channels and trapping chamber array are independently regulated pneumatically by two sets of integrated microfluidic valves. We successfully compress and aspirate the double emulsions, which result in transient increase and permanent decrease in oil thickness, respectively. Finally, we demonstrate the influx of calcium ions as a response of our mechanically activated artificial cell through thinning of oil. The development of a microfluidic device to mechanically activate artificial cells creates new opportunities in force-activated synthetic biology. PMID:27610921

  13. Mechanically activated artificial cell by using microfluidics

    NASA Astrophysics Data System (ADS)

    Ho, Kenneth K. Y.; Lee, Lap Man; Liu, Allen P.

    2016-09-01

    All living organisms sense mechanical forces. Engineering mechanosensitive artificial cell through bottom-up in vitro reconstitution offers a way to understand how mixtures of macromolecules assemble and organize into a complex system that responds to forces. We use stable double emulsion droplets (aqueous/oil/aqueous) to prototype mechanosensitive artificial cells. In order to demonstrate mechanosensation in artificial cells, we develop a novel microfluidic device that is capable of trapping double emulsions into designated chambers, followed by compression and aspiration in a parallel manner. The microfluidic device is fabricated using multilayer soft lithography technology, and consists of a control layer and a deformable flow channel. Deflections of the PDMS membrane above the main microfluidic flow channels and trapping chamber array are independently regulated pneumatically by two sets of integrated microfluidic valves. We successfully compress and aspirate the double emulsions, which result in transient increase and permanent decrease in oil thickness, respectively. Finally, we demonstrate the influx of calcium ions as a response of our mechanically activated artificial cell through thinning of oil. The development of a microfluidic device to mechanically activate artificial cells creates new opportunities in force-activated synthetic biology.

  14. The endochitinase VDECH from Verticillium dahliae inhibits spore germination and activates plant defense responses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Chitinases function in the digestion of chitin molecules, which are present principally in insects and fungi. In plants, chitinase genes play important roles in defense, and their expression can be triggered in response to both biotic and abiotic stresses. In this study, we cloned and characterized ...

  15. How to Incorporate Self-Defense Instruction into Physical Activity Programs

    ERIC Educational Resources Information Center

    Ousley, Christopher S.; Shuford, Ritchie G.; Roberts, Tom

    2013-01-01

    Demand for self-defense instruction has found its way to school settings at all levels. Classes are more prevalent on college campuses than ever before because students and administrators acknowledge the value of such instruction. As a point of reference, half of 16 University of North Carolina (UNC) schools and universities offer a course in…

  16. Low Levels of Polymorphism in Genes That Control the Activation of Defense Response in Arabidopsis thaliana

    PubMed Central

    Bakker, Erica G.; Traw, M. Brian; Toomajian, Christopher; Kreitman, Martin; Bergelson, Joy

    2008-01-01

    Plants use signaling pathways involving salicylic acid, jasmonic acid, and ethylene to defend against pathogen and herbivore attack. Many defense response genes involved in these signaling pathways have been characterized, but little is known about the selective pressures they experience. A representative set of 27 defense response genes were resequenced in a worldwide set of 96 Arabidopsis thaliana accessions, and patterns of single nucleotide polymorphisms (SNPs) were evaluated in relation to an empirical distribution of SNPs generated from either 876 fragments or 236 fragments with >400 bp coding sequence (this latter set was selected for comparisons with coding sequences) distributed across the genomes of the same set of accessions. Defense response genes have significantly fewer protein variants, display lower levels of nonsynonymous nucleotide diversity, and have fewer nonsynonymous segregating sites. The majority of defense response genes appear to be experiencing purifying selection, given the dearth of protein variation in this set of genes. Eight genes exhibit some evidence of partial selective sweeps or transient balancing selection. These results therefore provide a strong contrast to the high levels of balancing selection exhibited by genes at the upstream positions in these signaling pathways. PMID:18245336

  17. Department of Defense In-House RDT&E Activities. Management Analysis Report

    DTIC Science & Technology

    1987-10-30

    Chemical Defense . . ... . 36 Medical Research Institute of Infectious Diseases . . , . 37 Missile Research, Development & Engineering Center ... . 38...EOD, STATISTICAL, MAINT EVALUATION, AND HUMAN FACTORS CAPABILITIES AVAILABLE. COMPUTER SUPPORT AVAILABLE. TEMPERATURES TO -50 DEG. FAHR . COMMON. 19... DISEASE ; MAMMALIAN AND IN VITRO TOXICOLOGY; FORWARD AREA CASUALTY CARE. ...CURRENT IMPORTANT PROGRAMS DETERMINATION OF SAFE THRESHOLDS OF COHERENT

  18. High level resistance against rhizomania disease by simultaneously integrating two distinct defense mechanisms.

    PubMed

    Pavli, Ourania I; Tampakaki, Anastasia P; Skaracis, George N

    2012-01-01

    With the aim of achieving durable resistance against rhizomania disease of sugar beet, the employment of different sources of resistance to Beet necrotic yellow vein virus was pursued. To this purpose, Nicotiana benthamiana transgenic plants that simultaneously produce dsRNA originating from a conserved region of the BNYVV replicase gene and the HrpZ(Psph) protein in a secreted form (SP/HrpZ(Psph)) were produced. The integration and expression of both transgenes as well as proper production of the harpin protein were verified in all primary transformants and selfed progeny (T1, T2). Transgenic resistance was assessed by BNYVV-challenge inoculation on T2 progeny by scoring disease symptoms and DAS-ELISA at 20 and 30 dpi. Transgenic lines possessing single transformation events for both transgenes as well as wild type plants were included in inoculation experiments. Transgenic plants were highly resistant to virus infection, whereas in some cases immunity was achieved. In all cases, the resistant phenotype of transgenic plants carrying both transgenes was superior in comparison with the ones carrying a single transgene. Collectively, our findings demonstrate, for a first time, that the combination of two entirely different resistance mechanisms provide high level resistance or even immunity against the virus. Such a novel approach is anticipated to prevent a rapid virus adaptation that could potentially lead to the emergence of isolates with resistance breaking properties.

  19. Cell wall composition as a maize defense mechanism against corn borers.

    PubMed

    Barros-Rios, Jaime; Malvar, Rosa A; Jung, Hans-Joachim G; Santiago, Rogelio

    2011-04-01

    European and Mediterranean corn borers are two of the most economically important insect pests of maize (Zea mays L.) in North America and southern Europe, respectively. Cell wall structure and composition were evaluated in pith and rind tissues of resistant and susceptible inbred lines as possible corn borer resistance traits. Composition of cell wall polysaccharides, lignin concentration and composition, and cell wall bound forms of hydroxycinnamic acids were measured. As expected, most of the cell wall components were found at higher concentrations in the rind than in the pith tissues, with the exception of galactose and total diferulate esters. Pith of resistant inbred lines had significantly higher concentrations of total cell wall material than susceptible inbred lines, indicating that the thickness of cell walls could be the initial barrier against corn borer larvae attack. Higher concentrations of cell wall xylose and 8-O-4-coupled diferulate were found in resistant inbreds. Stem tunneling by corn borers was negatively correlated with concentrations of total diferulates, 8-5-diferulate and p-coumarate esters. Higher total cell wall, xylose, and 8-coupled diferulates concentrations appear to be possible mechanisms of corn borer resistance.

  20. Alternative activation deprives macrophages of a coordinated defense program to Mycobacterium tuberculosis.

    PubMed

    Kahnert, Antje; Seiler, Peter; Stein, Maik; Bandermann, Silke; Hahnke, Karin; Mollenkopf, Hans; Kaufmann, Stefan H E

    2006-03-01

    A potent Th1 immune response is critical to the control of tuberculosis. The impact of an additive Th2 response on the course of disease has so far been insufficiently characterized, despite increased morbidity after co-infection with Mycobacterium tuberculosis and Th2-eliciting helminths and possible involvement of Th2 polarization in reactivation of latent tuberculosis. Here, we describe the gene expression profile of murine bone marrow-derived macrophages alternatively activated by IL-4 in response to infection with M. tuberculosis. Comparison of transcriptional profiles of infected IL-4- and IFN-gamma-activated macrophages revealed delayed and partially diminished responses to intracellular bacteria in alternatively activated macrophages, characterized by reduced exposure to nitrosative stress and increased iron availability, respectively. Alternative activation of host macrophages correlated with elevated expression of the M. tuberculosis iron storage protein bacterioferritin as well as reduced expression of the mycobactin synthesis genes mbtI and mbtJ. The extracellular matrix-remodeling enzyme matrix metalloproteinase (MMP)-12 was induced in alternatively activated macrophages in vitro, and MMP-12-expressing macrophages were abundant at late, but not early, stages of tuberculosis in murine lungs. Our findings emphasize that alternative activation deprives macrophages of control mechanisms that limit mycobacterial growth in vivo, thus supporting intracellular persistence of M. tuberculosis.

  1. Effector-triggered immunity: from pathogen perception to robust defense.

    PubMed

    Cui, Haitao; Tsuda, Kenichi; Parker, Jane E

    2015-01-01

    In plant innate immunity, individual cells have the capacity to sense and respond to pathogen attack. Intracellular recognition mechanisms have evolved to intercept perturbations by pathogen virulence factors (effectors) early in host infection and convert it to rapid defense. One key to resistance success is a polymorphic family of intracellular nucleotide-binding/leucine-rich-repeat (NLR) receptors that detect effector interference in different parts of the cell. Effector-activated NLRs connect, in various ways, to a conserved basal resistance network in order to transcriptionally boost defense programs. Effector-triggered immunity displays remarkable robustness against pathogen disturbance, in part by employing compensatory mechanisms within the defense network. Also, the mobility of some NLRs and coordination of resistance pathways across cell compartments provides flexibility to fine-tune immune outputs. Furthermore, a number of NLRs function close to the nuclear chromatin by balancing actions of defense-repressing and defense-activating transcription factors to program cells dynamically for effective disease resistance.

  2. Effect of Calendula officinalis Flower Extract on Acute Phase Proteins, Antioxidant Defense Mechanism and Granuloma Formation During Thermal Burns

    PubMed Central

    Chandran, Preethi K.; Kuttan, Ramadasan

    2008-01-01

    Effect of Calendula officinalis flower extract was investigated against experimentally induced thermal burns in rats. Burn injury was made on the shaven back of the rats under anesthesia and the animals were treated orally with different doses of the flower extract (20 mg, 100 mg and 200 mg/kg body weight). The animals treated with the extract showed significant improvement in healing when compared with the control untreated animals. The indicators of the wound healing such as collagen-hydroxyproline and hexosamine contents were significantly increased in the treated group indicating accelerated wound healing in the treated animals. The acute phase proteins—haptoglobin and orosomucoid which were increased due to burn injury were found to be decreased significantly in 200 mg/kg body weight extract treated animals. The antioxidant defense mechanism, which was decreased in the liver during burn injury, was found to be enhanced in treated animals. The lipid peroxidation was significantly lowered in the treated group when compared to control animals. Tissue damage marker enzymes- alkaline phosphatase, alanine and aspartate transaminases were significantly lowered in the treated groups in a dose dependant manner. The histopathological analyses of skin tissue also give the evidence of the increased healing potential of the extract after burn injury. PMID:18818737

  3. The Drosophila PRR GNBP3 assembles effector complexes involved in antifungal defenses independently of its Toll pathway activation function

    PubMed Central

    Matskevich, Alexey A.; Quintin, Jessica; Ferrandon, Dominique

    2010-01-01

    Summary The Drosophila Toll signalling pathway controls the systemic antifungal host response. Gram-negative binding protein 3 (GNBP3), a member of the β-Glucan recognition protein (βGRP) family, senses fungal infections and activates this pathway. A second detection system perceives the activity of proteolytic fungal virulence factors and redundantly activates Toll. GNBP3hades mutant flies succumb more rapidly to Candida albicans and to entomopathogenic fungal infections than wild type (WT) flies, despite normal triggering of the Toll pathway via the virulence detection system. These observations suggest that GNBP3 triggers antifungal defenses that are not dependent on activation of the Toll pathway. Here, we show that GNBP3 agglutinates fungal cells. Furthermore, it can activate melanization in a Toll-independent manner. Melanization is likely to be an essential defense against some fungal infections since the entomopathogenic fungus B. bassiana inhibits the activity of the main melanization enzymes, the phenol oxidases. Finally, we show that GNBP3 assembles “attack complexes”, which comprise PO and the serpin NEC. We propose that Drosophila GNBP3 targets fungi immediately at the inception of the infection by bringing effector molecules in direct contact with the invading microorganisms. PMID:20201042

  4. The Drosophila PRR GNBP3 assembles effector complexes involved in antifungal defenses independently of its Toll-pathway activation function.

    PubMed

    Matskevich, Alexey A; Quintin, Jessica; Ferrandon, Dominique

    2010-05-01

    The Drosophila Toll-signaling pathway controls the systemic antifungal host response. Gram-negative binding protein 3 (GNBP3), a member of the beta-glucan recognition protein family senses fungal infections and activates this pathway. A second detection system perceives the activity of proteolytic fungal virulence factors and redundantly activates Toll. GNBP3(hades) mutant flies succumb more rapidly to Candida albicans and to entomopathogenic fungal infections than WT flies, despite normal triggering of the Toll pathway via the virulence detection system. These observations suggest that GNBP3 triggers antifungal defenses that are not dependent on activation of the Toll pathway. Here, we show that GNBP3 agglutinates fungal cells. Furthermore, it can activate melanization in a Toll-independent manner. Melanization is likely to be an essential defense against some fungal infections given that the entomopathogenic fungus Beauveria bassiana inhibits the activity of the main melanization enzymes, the phenol oxidases. Finally, we show that GNBP3 assembles "attack complexes", which comprise phenoloxidase and the necrotic serpin. We propose that Drosophila GNBP3 targets fungi immediately at the inception of the infection by bringing effector molecules in direct contact with the invading microorganisms.

  5. The mitogen-activated protein kinase p38 is involved in insect defense against Cry toxins from Bacillus thuringiensis

    PubMed Central

    Cancino-Rodezno, Angeles; Alexander, Cynthia; Villaseñor, Roberto; Pacheco, Sabino; Porta, Helena; Pauchet, Yannick; Soberón, Mario; Gill, Sarjeet S.; Bravo, Alejandra

    2010-01-01

    The insecticidal Cry toxins are pore-forming toxins produced by the bacteria Bacillus thuringiensis that disrupt insect-midgut cells. In this work we analyzed the response of two different insect orders, the Lepidopteran Manduca sexta and Dipteran Aedes aegypti to highly specific Cry toxins, Cry1Ab and Cry11Aa, respectively. One pathway activated in different organisms in response to a variety of pore forming toxins is the mitogen activated protein kinase p38 pathway (MAPK p38) that activates a complex defense response. We analyzed the MAPK p38 activation by immunodetection of its phosphorylated isoform, and the induction of p38 by RT-PCR, real time-PCR quantitative assays and immunodection. We show that MAPK p38 is activated at postraductional level after Cry toxin intoxication in both insect orders. We detected the p38 induction at the transcriptional and traductional level, and observed a different response. In these three levels, we found that both insects respond to Cry toxin action but M sexta responses more strongly than A. aegypti. Gene silencing of MAPK p38 in vivo, resulted in both insect species becoming hypersensitive to Cry toxin action, suggesting that the MAPK p38 pathway is involved in insect defense against Bt Cry toxins. This finding may have biotechnological applications for enhancing the activity of some Bt Cry toxins against specific insect pests. PMID:20040372

  6. Mechanism of FGF receptor dimerization and activation

    NASA Astrophysics Data System (ADS)

    Sarabipour, Sarvenaz; Hristova, Kalina

    2016-01-01

    Fibroblast growth factors (fgfs) are widely believed to activate their receptors by mediating receptor dimerization. Here we show, however, that the FGF receptors form dimers in the absence of ligand, and that these unliganded dimers are phosphorylated. We further show that ligand binding triggers structural changes in the FGFR dimers, which increase FGFR phosphorylation. The observed effects due to the ligands fgf1 and fgf2 are very different. The fgf2-bound dimer structure ensures the smallest separation between the transmembrane (TM) domains and the highest possible phosphorylation, a conclusion that is supported by a strong correlation between TM helix separation in the dimer and kinase phosphorylation. The pathogenic A391E mutation in FGFR3 TM domain emulates the action of fgf2, trapping the FGFR3 dimer in its most active state. This study establishes the existence of multiple active ligand-bound states, and uncovers a novel molecular mechanism through which FGFR-linked pathologies can arise.

  7. Emerging roles of RB family: new defense mechanisms against tumor progression.

    PubMed

    Indovina, Paola; Marcelli, Eleonora; Casini, Nadia; Rizzo, Valeria; Giordano, Antonio

    2013-03-01

    The retinoblastoma (RB) family of proteins, including RB1/p105, retinoblastoma-like 1 (RBL1/p107), and retinoblastoma-like 2 (RBL2/p130), is principally known for its central role on cell cycle regulation. The inactivation of RB proteins confers a growth advantage and underlies multiple types of tumors. Recently, it has been shown that RB proteins have other important roles, such as preservation of chromosomal stability, induction and maintenance of senescence and regulation of apoptosis, cellular differentiation, and angiogenesis. RB proteins are involved in many cellular pathways and act as transcriptional regulators able to bind several transcription factors, thus antagonizing or potentiating their functions. Furthermore, RB proteins might control the expression of specific target genes by recruiting chromatin remodeling enzymes. Although many efforts have been made to dissect the different functions of RB proteins, it remains still unclear which are necessary for cancer suppression and the role they play at distinct steps of carcinogenesis. Moreover, RB proteins can behave differently in various cell types or cell states. Elucidating the intricate RB protein network in regulating cell fate might provide the knowledge necessary to explain their potent tumor suppressor activity and to design novel therapeutic strategies.

  8. A Systems Engineering Approach to Aircraft Kinetic Kill Countermeasures Technology: Development of an Active Aircraft Defense System for the C/KC-135 Aircraft. Volume 1

    DTIC Science & Technology

    1995-12-01

    AFIT/GSE/ENY/95D-01 A SYSTEMS ENGINEERING APPROACH TO AIRCRAFT KINETIC KILL COUNTERMEASURE TECHNOLOGY: DEVELOPMENT OF AN ACTIVE AIR DEFENSE SYSTEM...AFIT/GSE/ENY/95D-01 A SYSTEMS ENGINEERING APPROACH TO AIRCRAFT KINETIC KILL COUNTERMEASURE TECHNOLOGY: DEVELOPMENT OF AN ACTIVE AIR DEFENSE SYSTEM FOR...THE C/KC-135 AIRCRAFT THESIS (1 of2) Presented to the Faculty of the Graduate School of Engineering of the Air Force Institute of Technology Air

  9. STAT3 activation in Th17 and Th22 cells controls IL-22-mediated epithelial host defense during infectious colitis.

    PubMed

    Backert, Ingo; Koralov, Sergei B; Wirtz, Stefan; Kitowski, Vera; Billmeier, Ulrike; Martini, Eva; Hofmann, Katharina; Hildner, Kai; Wittkopf, Nadine; Brecht, Katrin; Waldner, Maximilian; Rajewsky, Klaus; Neurath, Markus F; Becker, Christoph; Neufert, Clemens

    2014-10-01

    The Citrobacter rodentium model mimics the pathogenesis of infectious colitis and requires sequential contributions from different immune cell populations, including innate lymphoid cells (ILCs) and CD4(+) lymphocytes. In this study, we addressed the role of STAT3 activation in CD4(+) cells during host defense in mice against C. rodentium. In mice with defective STAT3 in CD4(+) cells (Stat3(ΔCD4)), the course of infection was unchanged during the innate lymphoid cell-dependent early phase, but significantly altered during the lymphocyte-dependent later phase. Stat3(ΔCD4) mice exhibited intestinal epithelial barrier defects, including downregulation of antimicrobial peptides, increased systemic distribution of bacteria, and prolonged reduction in the overall burden of C. rodentium infection. Immunomonitoring of lamina propria cells revealed loss of virtually all IL-22-producing CD4(+) lymphocytes, suggesting that STAT3 activation was required for IL-22 production not only in Th17 cells, but also in Th22 cells. Notably, the defective host defense against C. rodentium in Stat3(∆CD4) mice could be fully restored by specific overexpression of IL-22 through a minicircle vector-based technology. Moreover, expression of a constitutive active STAT3 in CD4(+) cells shaped strong intestinal epithelial barrier function in vitro and in vivo through IL-22, and it promoted protection from enteropathogenic bacteria. Thus, our work indicates a critical role of STAT3 activation in Th17 and Th22 cells for control of the IL-22-mediated host defense, and strategies expanding STAT3-activated CD4(+) lymphocytes may be considered as future therapeutic options for improving intestinal barrier function in infectious colitis.

  10. Abscisic acid activates a Ca2+-calmodulin-stimulated protein kinase involved in antioxidant defense in maize leaves.

    PubMed

    Xu, Shucheng

    2010-09-01

    The role of a calcium-dependent and calmodulin (CaM)-stimulated protein kinase in abscisic acid (ABA)-induced antioxidant defense was determined in leaves of maize (Zea mays). In-gel kinase assays showed that treatments with ABA or H(2)O(2) induced the activation of a 49-kDa protein kinase and a 52-kDa protein kinase significantly. Furthermore, we showed that the 52-kDa protein kinase has the characteristics of CaM-stimulating activity and is sensitive to calcium-CaM-dependent protein kinase II (CaMK II) inhibitor KN-93 or CaM antagonist W-7. Treatments with ABA or H(2)O(2) not only induced the activation of the 52-kDa protein kinase, but also enhanced the total activities of the antioxidant enzymes, including catalase, ascorbate peroxidase, glutathione reductase, and superoxide dismutase. Such enhancements were blocked by pretreatment with a CaMK inhibitor and a reactive oxygen species (ROS) inhibitor or scavenger. Pretreatment with the CaMK inhibitor also substantially arrested the ABA-induced H(2)O(2) production. Kinase activity enhancements induced by ABA were attenuated by pretreatment with an ROS inhibitor or scavenger. These results suggest that the 52-kDa CaMK is involved in ABA-induced antioxidant defense and that cross-talk between CaMK and H(2)O(2) plays a pivotal role in ABA signaling. We infer that CaMK acts both upstream and downstream of H(2)O(2), but mainly acts between ABA and H(2)O(2) in ABA-induced antioxidant-defensive signaling.

  11. N-Acylethanolamines in Signal Transduction of Elicitor Perception. Attenuation of Alkalinization Response and Activation of Defense Gene Expression1

    PubMed Central

    Tripathy, Swati; Venables, Barney J.; Chapman, Kent D.

    1999-01-01

    In a recent study of N-acylphosphatidylethanolamine (NAPE) metabolism in elicitor-treated tobacco (Nicotiana tabacum L.) cells, we identified a rapid release and accumulation of medium-chain N-acylethanolamines (NAEs) (e.g. N-myristoylethanolamine or NAE 14:0) and a compensatory decrease in cellular NAPE (K.D. Chapman, S. Tripathy, B. Venables, A.D. Desouza [1998] Plant Physiol 116: 1163–1168). In the present study, we extend this observation and report a 10- to 50-fold increase in NAE 14:0 content in leaves of tobacco (cv Xanthi) plants treated with xylanase or cryptogein elicitors. Exogenously supplied synthetic NAE species affected characteristic elicitor-induced and short- and long-term defense responses in cell suspensions of tobacco and long-term defense responses in leaves of intact tobacco plants. In general, synthetic NAEs inhibited elicitor-induced medium alkalinization by tobacco cells in a time- and concentration-dependent manner. Exogenous NAE 14:0 induced expression of phenylalanine ammonia lyase in a manner similar to fungal elicitors in both cell suspensions and leaves of tobacco. NAE 14:0, but not myristic acid, activated phenylalanine ammonia lyase expression at submicromolar concentrations, well within the range of NAE 14:0 levels measured in elicitor-treated plants. Collectively, these results suggest that NAPE metabolism, specifically, the accumulation of NAE 14:0, are part of a signal transduction pathway that modulates cellular defense responses following the perception of fungal elicitors. PMID:10594117

  12. Activities of the Institute for Mechanical Engineering

    NASA Astrophysics Data System (ADS)

    The Institute of Mechanical Engineering (IME) is part of Canada's National Research Council. Its mission is to undertake, support, promote, and disseminate research and development in the mechanical engineering aspects of three vital sectors of the Canadian economy: transportation, resource industries, and manufacturing. The IME achieves its mission by performing research and development in its own facilities; by developing, providing, and transferring expertise and knowledge; by making its research facilities available to collaborators and clients; and by participating in international liaison and collaborative research activities. Six research programs are conducted in the IME: Advanced Manufacturing Technology; Coastal Zone Engineering; Cold Regions Engineering; Combustion and Fluids Engineering; Ground Transportation Technology; and Machinery and Engine Technology. The rationale and major research thrusts of each program are described, and specific achievements in 1991-92 are reviewed. Lists of technical reports and papers presented by IME personnel are also included.

  13. The plant growth-promoting fungus Penicillium simplicissimum GP17-2 induces resistance in Arabidopsis thaliana by activation of multiple defense signals.

    PubMed

    Hossain, Md Motaher; Sultana, Farjana; Kubota, Mayumi; Koyama, Hiroyuki; Hyakumachi, Mitsuro

    2007-12-01

    Arabidopsis thaliana grown in soil amended with barley grain inocula of Penicillium simplicissimum GP17-2 or receiving root treatment with its culture filtrate (CF) exhibited clear resistance to Pseudomonas syringae pv. tomato DC3000 (Pst). To assess the contribution of different defense pathways, Arabidopsis genotypes implicated in salicylic acid (SA) signaling expressing the NahG transgene or carrying disruption in NPR1 (npr1), jasmonic acid (JA) signaling (jar1) and ethylene (ET) signaling (ein2) were tested. All genotypes screened were protected by GP17-2 or its CF. However, the level of protection was significantly lower in NahG and npr1 plants than it was in similarly treated wild-type plants, indicating that the SA signaling pathway makes a minor contribution to the GP17-2-mediated resistance and is insufficient for a full response. Examination of local and systemic gene expression revealed that GP17-2 and its CF modulate the expression of genes involved in both the SA and JA/ET signaling pathways. Subsequent challenge of GP17-2-colonized plants with Pst was accompanied by direct activation of SA-inducible PR-2 and PR-5 genes as well as potentiated expression of the JA-inducible Vsp gene. In contrast, CF-treated plants infected with Pst exhibited elevated expression of most defense-related genes (PR-1, PR-2, PR-5, PDF1.2 and Hel) studied. Moreover, an initial elevation of SA responses was followed by late induction of JA responses during Pst infection of induced systemic resistance (ISR)-expressing plants. In conclusion, we hypothesize the involvement of multiple defense mechanisms leading to an ISR of Arabidopsis by GP17-2.

  14. PeBL1, a novel protein elicitor from Brevibacillus laterosporus strain A60, activates defense responses and systemic resistance in Nicotiana benthamiana.

    PubMed

    Wang, Haoqian; Yang, Xiufen; Guo, Lihua; Zeng, Hongmei; Qiu, Dewen

    2015-04-01

    We report the identification, characterization, and gene cloning of a novel protein elicitor (PeBL1) secreted from Brevibacillus laterosporus strain A60. Through a purification process consisting of ion-exchange chromatography and high-performance liquid chromatography (HPLC), we isolated a protein that was identified by electrospray ionization quadrupole time of flight tandem mass spectrometry (ESI-Q-TOF-MS-MS). The 351-bp PeBL1 gene produces a 12,833-Da protein with 116 amino acids that contains a 30-residue signal peptide. The PeBL1 protein was expressed in Escherichia coli. The recombinant protein can induce a typical hypersensitive response (HR) and systemic resistance in Nicotiana benthamiana, like the endogenous protein. PeBL1-treated N. benthamiana exhibited strong resistance to the infection of tobacco mosaic virus-green fluorescent protein (TMV-GFP) and Pseudomonas syringae pv. tabaci compared to control N. benthamiana. In addition, PeBL1 triggered a cascade of events that resulted in defense responses in plants, including reactive oxygen species (ROS) production, extracellular-medium alkalization, phenolic-compound deposition, and expression of several defense-related genes. Real-time quantitative-PCR analysis indicated that the known defense-related genes PR-1, PR-5, PDF1.2, NPR1, and PAL were upregulated to varying degrees by PeBL1. This research not only provides insights into the mechanism by which beneficial bacteria activate plant systemic resistance, but also sheds new light on a novel strategy for biocontrol using strain A60.

  15. PeBL1, a Novel Protein Elicitor from Brevibacillus laterosporus Strain A60, Activates Defense Responses and Systemic Resistance in Nicotiana benthamiana

    PubMed Central

    Wang, Haoqian; Yang, Xiufen; Guo, Lihua; Zeng, Hongmei

    2015-01-01

    We report the identification, characterization, and gene cloning of a novel protein elicitor (PeBL1) secreted from Brevibacillus laterosporus strain A60. Through a purification process consisting of ion-exchange chromatography and high-performance liquid chromatography (HPLC), we isolated a protein that was identified by electrospray ionization quadrupole time of flight tandem mass spectrometry (ESI–Q-TOF–MS-MS). The 351-bp PeBL1 gene produces a 12,833-Da protein with 116 amino acids that contains a 30-residue signal peptide. The PeBL1 protein was expressed in Escherichia coli. The recombinant protein can induce a typical hypersensitive response (HR) and systemic resistance in Nicotiana benthamiana, like the endogenous protein. PeBL1-treated N. benthamiana exhibited strong resistance to the infection of tobacco mosaic virus-green fluorescent protein (TMV-GFP) and Pseudomonas syringae pv. tabaci compared to control N. benthamiana. In addition, PeBL1 triggered a cascade of events that resulted in defense responses in plants, including reactive oxygen species (ROS) production, extracellular-medium alkalization, phenolic-compound deposition, and expression of several defense-related genes. Real-time quantitative-PCR analysis indicated that the known defense-related genes PR-1, PR-5, PDF1.2, NPR1, and PAL were upregulated to varying degrees by PeBL1. This research not only provides insights into the mechanism by which beneficial bacteria activate plant systemic resistance, but also sheds new light on a novel strategy for biocontrol using strain A60. PMID:25662975

  16. Policy Options for Sharing Activities between the Department of Veterans Affairs and the Department of Defense

    DTIC Science & Technology

    2007-06-14

    taxpayer dollars as described in the President’s Management Agenda, the document which codifies the Bush administration’s strategy for improving...an imperfect market , defensive medicine, practice variations, etc. (Shi & Sing, 2004). A key factor affecting the nation’s health care costs as a...report often speaks volumes. For example, in the 2000 Government Accountability Office testimony titled, "Rethinking of Resource Sharing Strategies is

  17. Improving the Oversight of Defense Agencies and DoD Field Activities.

    DTIC Science & Technology

    1987-05-01

    I •Exchange Group and the Joint Nuclear Accident Coordinating Center. ":’Ŕ In 1961, AFSWP was reorganized and redesignated as the Defense Atomic...and other DoD and non-DoD Government Agencies. - 0 In 1978, DNA was assigned the responsibility for ensuring theater nucleair ’ ~. forces survivability...0 In 1979, DNA was assigned the responsibility for determining how to respond in case of a nuclear accident . The current DNA charter is contained in

  18. Salicylic acid-mediated and RNA-silencing defense mechanisms cooperate in the restriction of systemic spread of plum pox virus in tobacco.

    PubMed

    Alamillo, Josefa M; Saénz, Pilar; García, Juan Antonio

    2006-10-01

    Plum pox virus (PPV) is able to replicate in inoculated leaves of Nicotiana tabacum, but is defective in systemic movement in this host. However, PPV produces a systemic infection in transgenic tobacco expressing the silencing suppressor P1/HC-Pro from tobacco etch virus (TEV). In this work we show that PPV is able to move to upper non-inoculated leaves of tobacco plants expressing bacterial salicylate hydroxylase (NahG) that degrades salicylic acid (SA). Replication and accumulation of PPV is higher in the locally infected leaves of plants deficient in SA or expressing TEV P1/HC-Pro silencing suppressor. Accumulation of viral derived small RNAs was reduced in the NahG transgenic plants, suggesting that SA might act as an enhancer of the RNA-silencing antiviral defense in tobacco. Besides, expression of SA-mediated defense transcripts, such as those of pathogenesis-related (PR) proteins PR-1 and PR-2 or alternative oxidase-1, as well as that of the putative RNA-dependent RNA polymerase NtRDR1, is induced in response to PPV infection, and the expression patterns of these defense transcripts are altered in the TEV P1/HC-Pro transgenic plants. Long-distance movement of PPV is highly enhanced in NahG x P1/HC-Pro double-transgenic plants and systemic symptoms in these plants reveal that the expression of an RNA-silencing suppressor and the lack of SA produce additive but distinct effects. Our results suggest that SA might act as an enhancer of the RNA-silencing antiviral defense in tobacco, and that silencing suppressors, such as P1/HC-Pro, also alter the SA-mediated defense. Both an RNA-silencing and an SA-mediated defense mechanism could act together to limit PPV infection.

  19. Activation of defense against Phytophthora infestans in potato by down-regulation of syntaxin gene expression.

    PubMed

    Eschen-Lippold, Lennart; Landgraf, Ramona; Smolka, Ulrike; Schulze, Sebastian; Heilmann, Mareike; Heilmann, Ingo; Hause, Gerd; Rosahl, Sabine

    2012-03-01

    The oomycete Phytophthora infestans is the causal agent of late blight, the most devastating disease of potato. The importance of vesicle fusion processes and callose deposition for defense of potato against Phytophthora infestans was analyzed. Transgenic plants were generated, which express RNA interference constructs targeted against plasma membrane-localized SYNTAXIN-RELATED 1 (StSYR1) and SOLUBLE N-ETHYLMALEIMIDE-SENSITIVE FACTOR ADAPTOR PROTEIN 33 (StSNAP33), the potato homologs of Arabidopsis AtSYP121 and AtSNAP33, respectively. Phenotypically, transgenic plants grew normally, but showed spontaneous necrosis and chlorosis formation at later stages. In response to infection with Phytophthora infestans, increased resistance of StSYR1-RNAi plants, but not StSNAP33-RNAi plants, was observed. This increased resistance correlated with the constitutive accumulation of salicylic acid and PR1 transcripts. Aberrant callose deposition in Phytophthora infestans-infected StSYR1-RNAi plants coincided with decreased papilla formation at penetration sites. Resistance against the necrotrophic fungus Botrytis cinerea was not significantly altered. Infiltration experiments with bacterial solutions of Agrobacterium tumefaciens and Escherichia coli revealed a hypersensitive phenotype of both types of RNAi lines. The enhanced defense status and the reduced growth of Phytophthora infestans on StSYR1-RNAi plants suggest an involvement of syntaxins in secretory defense responses of potato and, in particular, in the formation of callose-containing papillae.

  20. Molecular Mechanisms of DNA Replication Checkpoint Activation

    PubMed Central

    Recolin, Bénédicte; van der Laan, Siem; Tsanov, Nikolay; Maiorano, Domenico

    2014-01-01

    The major challenge of the cell cycle is to deliver an intact, and fully duplicated, genetic material to the daughter cells. To this end, progression of DNA synthesis is monitored by a feedback mechanism known as replication checkpoint that is untimely linked to DNA replication. This signaling pathway ensures coordination of DNA synthesis with cell cycle progression. Failure to activate this checkpoint in response to perturbation of DNA synthesis (replication stress) results in forced cell division leading to chromosome fragmentation, aneuploidy, and genomic instability. In this review, we will describe current knowledge of the molecular determinants of the DNA replication checkpoint in eukaryotic cells and discuss a model of activation of this signaling pathway crucial for maintenance of genomic stability. PMID:24705291

  1. Mechanism and active variety of allelochemicals

    USGS Publications Warehouse

    Peng, S.-L.; Wen, J.; Guo, Q.-F.

    2004-01-01

    This article summarizes allelochemicals' active variety, its potential causes and function mechanisms. Allelochemicals' activity varies with temperature, photoperiod, water and soils during natural processes, with its initial concentration, compound structure and mixed degree during functional processes, with plant accessions, tissues and maturity within-species, and with research techniques and operation processes. The prospective developmental aspects of allelopathy studies in the future are discussed. Future research should focus on: (1) to identify and purify allelochemicals more effectively, especially for agriculture, (2) the functions of allelopathy at the molecular structure level, (3) using allelopathy to explain plant species interactions, (4) allelopathy as a driving force of succession, and (5) the significance of allelopathy in the evolutionary processes.

  2. [Regulation effect of calcium and salicylic acid on defense enzyme activities in tomato leaves under sub-high temperature stress].

    PubMed

    Li, Tian-lai; Li, Miao; Sun, Zhou-ping

    2009-03-01

    In order to investigate the regulation effect of Ca2+ and salicylic acid (SA) on the sub-high temperature resistance of tomato plants, the plants were treated with sub-high temperature (35 degrees C) at day time during their 1st inflorescence flowering, and CaCl2 (10 mmol x L(-1)) and SA (0.2 mmol x (L(-1 were foliar sprayed to study the variations of the activities of defense enzymes (SOD, POD, and CAT) and the content of soluble protein in tomato leaves, taking spraying clear water under 25 degrees C at day time as the control. The results showed that under the sub-high temperature stress, the SOD, CAT and POD activities in tomato leaves were decreased by 14.82%, 31.84%, and 26.34%, respectively, while spraying CaCl2 (10 mmol x L(-1)) and SA (0.2 mmol x L(-1)) decreased the leaf MDA content and increased the leaf SOD, POD and CAT activities and soluble protein content, compared with the control, indicating that Ca2+ and SA had positive regulation effect on the defense enzyme activities in tomato leaves, which could protect the photosynthetic system of tomato under the sub-high temperature stress to a certain degree.

  3. Possible involvement of self-defense mechanisms in the preferential vulnerability of the striatum in Huntington's disease

    PubMed Central

    Francelle, Laetitia; Galvan, Laurie; Brouillet, Emmanuel

    2014-01-01

    HD is caused by a mutation in the huntingtin gene that consists in a CAG repeat expansion translated into an abnormal poly-glutamine (polyQ) tract in the huntingtin (Htt) protein. The most striking neuropathological finding in HD is the atrophy of the striatum. The regional expression of mutant Htt (mHtt) is ubiquitous in the brain and cannot explain by itself the preferential vulnerability of the striatum in HD. mHtt has been shown to produce an early defect in transcription, through direct alteration of the function of key regulators of transcription and in addition, more indirectly, as a result of compensatory responses to cellular stress. In this review, we focus on gene products that are preferentially expressed in the striatum and have down- or up-regulated expression in HD and, as such, may play a crucial role in the susceptibility of the striatum to mHtt. Many of these striatal gene products are for a vast majority down-regulated and more rarely increased in HD. Recent research shows that some of these striatal markers have a pro-survival/neuroprotective role in neurons (e.g., MSK1, A2A, and CB1 receptors) whereas others enhance the susceptibility of striatal neurons to mHtt (e.g., Rhes, RGS2, D2 receptors). The down-regulation of these latter proteins may be considered as a potential self-defense mechanism to slow degeneration. For a majority of the striatal gene products that have been identified so far, their function in the striatum is unknown and their modifying effects on mHtt toxicity remain to be experimentally addressed. Focusing on these striatal markers may contribute to a better understanding of HD pathogenesis, and possibly the identification of novel therapeutic targets. PMID:25309327

  4. The reproductive toxicity on the rotifer Brachionus plicatilis induced by BDE-47 and studies on the effective mechanism based on antioxidant defense system changes.

    PubMed

    Wang, Hong; Tang, Xuexi; Sha, Jingjing; Chen, Hongmei; Sun, Tianli; Wang, You

    2015-09-01

    2,2',4,4'-Tetrabromodiphenyl ether (BDE-47), a low-brominated Tetra-BDE that is widely distributed in the marine ecosystem, was selected to investigate the reproductive toxicity on the rotifer, Brachionus plicatilis, and the possible mechanism based on antioxidant defense system changes were studied. The results showed the following: (1) A low concentration of BDE-47 had a slight effect on the egg production of individual females and the egg production rate (EPR) of the population. In fact, BDE-47 exerted reproductive inhibition effects in a time- and concentration-dependent manner. The obtained life tables indicated that BDE-47 at a high concentration prolonged the generation time, whereas low and moderate concentrations of BDE-47 had the opposite effects. BDE-47 at a medium concentration significantly decreased the life expectancy and net reproductive rate (P<0.05). Additionally, a high concentration of BDE-47 markedly decreased the net reproductive rate and intrinsic increase rate (P<0.05). The ultra-structure of the ovary showed that BDE-47 severely damaged the ovary. (2) BDE-47 stress elevated the ROS level in B. plicatilis. The GST activity was induced significantly by the low concentration of BDE-47 and inhibited by the highest concentration tested. The GPx activity and GSH content were significant decreased in all the tested groups, and GR activity was induced. GST and GSH appeared to be sensitive to oxidative stress, and all of the glutathione-related enzymes were found to play an important role in maintaining the antioxidant/pro-oxidant balance based on Pearson's correlation analysis. The results indicated that BDE-47 causes reproductive toxicity in B. plicatilis and that the ROS-mediated pathway is responsible for the observed toxicity.

  5. Induction of leucine aminopeptidase (LAP) like activity with wounding and methyl jasmonate in pigeonpea (Cajanas cajan) suggests the role of these enzymes in plant defense in leguminosae.

    PubMed

    Lomate, Purushottam R; Hivrale, Vandana K

    2011-06-01

    Aminopeptidases are ubiquitous in nature and their activities have been identified in several plant species. Leucine aminopeptidases (LAPs) are predominantly studied in solanaceous plants and are induced in response to wounding, herbivory and methyl jasmonate (MeJA). The functions of plant aminopeptidases are still under discussion and it is likely that the different classes play various roles. In the present study we report the local and systemic induction of LAP-like activity upon mechanical wounding and MeJA treatment. Two proteins with LAP-like activity were detected in pigeonpea leaves. They were designated as AP1 and AP2. AP1 activity was significantly induced upon wounding and application of MeJA. The estimated molecular masses of AP1 and AP2 were ∼ 60 and 41 kDa respectively in SDS-PAGE. The pH optimum for LAP-like activity in control leaf extracts was found to be neutral (pH 7.0) however the enzymes showed highest activity at alkaline pH (pH 9.0) in the leaf extracts of treated plants. The temperature optimum for LAP-like activity was around 40-50 °C. The enzymes were strongly inhibited by 1, 10 phenanthroline and bestatin. Heavy metal ions and EDTA inhibited LAP-like activities, whereas Mn(+2) and Mg(+2) activated the enzyme activities. Beside LpNA (33.5 U/mg/min) pigeonpea LAP-like enzymes also cleaved ApNA (15 U/mg/min) but were unable to cleave VpNA. Total proteolytic activity was also observed to be induced in treated plants. LAP-like activity was increased upto 19.5 fold after gel filtration chromatography. Results suggest that these enzymes may have functional defensive role in pigeonpea.

  6. Mechanism of Highly Synchronized Bilateral Hippocampal Activity

    PubMed Central

    Wang, Y.; Toprani, S.; Tang, Y.; Vrabec, T.; Durand, D.M.

    2014-01-01

    In vivo studies of epileptiform discharges in the hippocampi of rodents have shown that bilateral seizure activity can sometimes be synchronized with very small delays (< 2 ms). This observed small time delay of epileptiform activity between the left and right CA3 regions is unexpected given the physiological propagation time across the hemispheres (> 6 ms). The goal of this study is to determine the mechanisms of this tight synchronization with in-vitro electrophysiology techniques and computer simulations. The hypothesis of a common source was first eliminated by using an in-vitro preparation containing both hippocampi with a functional ventral hippocampal commissure (VHC) and no other tissue. Next, the hypothesis that a noisy baseline could mask the underlying synchronous activity between the two hemispheres was ruled out by low noise in-vivo recordings and computer simulation of the noisy environment. Then we built a novel bilateral CA3 model to test the hypothesis that the phenomenon of very small left-to-right propagation delay of seizure activity is a product of epileptic cell network dynamics. We found that the commissural tract connectivity could decrease the delay between seizure events recorded from two sides while the activity propagated longitudinally along the CA3 layer thereby yielding delays much smaller than the propagation time between the two sides. The modeling results indicate that both recurrent and feedforward inhibition were required for shortening the bilateral propagation delay and depended critically on the length of the commissural fiber tract as well as the number of cells involved in seizure generation. These combined modeling/experimental studies indicate that it is possible to explain near perfect synchronization between the two hemispheres by taking into account the structure of the hippocampal network. PMID:24262205

  7. Mechanism of base activation of persulfate.

    PubMed

    Furman, Olha S; Teel, Amy L; Watts, Richard J

    2010-08-15

    Base is the most commonly used activator of persulfate for the treatment of contaminated groundwater by in situ chemical oxidation (ISCO). A mechanism for the base activation of persulfate is proposed involving the base-catalyzed hydrolysis of persulfate to hydroperoxide anion and sulfate followed by the reduction of another persulfate molecule by hydroperoxide. Reduction by hydroperoxide decomposes persulfate into sulfate radical and sulfate anion, and hydroperoxide is oxidized to superoxide. The base-catalyzed hydrolysis of persulfate was supported by kinetic analyses of persulfate decomposition at various base:persulfate molar ratios and an increased rate of persulfate decomposition in D(2)O vs H(2)O. Stoichiometric analyses confirmed that hydroperoxide reacts with persulfate in a 1:1 molar ratio. Addition of hydroperoxide to basic persulfate systems resulted in rapid decomposition of the hydroperoxide and persulfate and decomposition of the superoxide probe hexachloroethane. The presence of superoxide was confirmed with scavenging by Cu(II). Electron spin resonance spectroscopy confirmed the generation of sulfate radical, hydroxyl radical, and superoxide. The results of this research are consistent with the widespread reactivity reported for base-activated persulfate when it is used for ISCO.

  8. Antiviral Activity of Myticin C Peptide from Mussel: an Ancient Defense against Herpesviruses

    PubMed Central

    Romero, Alejandro; Pereiro, Patricia; Costa, María M.; Dios, Sonia; Estepa, Amparo; Parra, Francisco; Figueras, Antonio

    2016-01-01

    ABSTRACT Little is known about the antiviral response in mollusks. As in other invertebrates, the interferon signaling pathways have not been identified, and in fact, there is a debate about whether invertebrates possess antiviral immunity similar to that of vertebrates. In marine bivalves, due to their filtering activity, interaction with putative pathogens, including viruses, is very high, suggesting that they should have mechanisms to address these infections. In this study, we confirmed that constitutively expressed molecules in naive mussels confer resistance in oysters to ostreid herpesvirus 1 (OsHV-1) when oyster hemocytes are incubated with mussel hemolymph. Using a proteomic approach, myticin C peptides were identified in both mussel hemolymph and hemocytes. Myticins, antimicrobial peptides that have been previously characterized, were constitutively expressed in a fraction of mussel hemocytes and showed antiviral activity against OsHV-1, suggesting that these molecules could be responsible for the antiviral activity of mussel hemolymph. For the first time, a molecule from a bivalve has shown antiviral activity against a virus affecting mollusks. Moreover, myticin C peptides showed antiviral activity against human herpes simplex viruses 1 (HSV-1) and 2 (HSV-2). In summary, our work sheds light on the invertebrate antiviral immune response with the identification of a molecule with potential biotechnological applications. IMPORTANCE Several bioactive molecules that have potential pharmaceutical or industrial applications have been identified and isolated from marine invertebrates. Myticin C, an antimicrobial peptide from the Mediterranean mussel (Mytilus galloprovincialis) that was identified by proteomic techniques in both mussel hemolymph and hemocytes, showed potential as an antiviral agent against ostreid herpesvirus 1 (OsHV-1), which represents a major threat to the oyster-farming sector. Both hemolymph from mussels and a myticin C peptide inhibited Os

  9. Peripheral mechanisms II: the pharmacology of peripherally active antitussive drugs.

    PubMed

    Spina, D; McFadzean, I; Bertram, F K R; Page, C P

    2009-01-01

    Cough is an indispensable defensive reflex. Although generally beneficial, it is also a common symptom of diseases such as asthma, chronic obstructive pulmonary disease, upper respiratory tract infections, idiopathic pulmonary fibrosis and lung cancer. Cough remains a major unmet medical need and although the centrally acting opioids have remained the antitussive of choice for decades, they have many unwanted side effects. However, new research into the behaviour of airway sensory nerves has provided greater insight into the mechanisms of cough and new avenues for the discovery of novel non-opioid antitussive drugs. In this review, the pathophysiological mechanisms of cough and the development of novel antitussive drugs are reviewed.

  10. Tricking the guard: Exploiting Plant Defense for Disease Susceptibility

    PubMed Central

    Lorang, J.; Kidarsa, T.; Bradford, C. S.; Gilbert, B.; Curtis, M.; Tzeng, S-C.; Maier, C.S.; Wolpert, T. J.

    2014-01-01

    Typically pathogens deploy virulence effectors to disable defense. Plants defeat effectors with resistance proteins that guard effector targets. Here we show that a pathogen exploits a resistance protein by activating it to confer susceptibility. Interactions of victorin, an effector produced by the necrotrophic fungus Cochliobolus victoriae, TRX-h5, a defense-associated thioredoxin, and LOV1, an Arabidopsis susceptibility protein, recapitulate the guard mechanism of plant defense. In LOV1’s absence, victorin inhibits TRX-h5 resulting in compromised defense but not disease by C. victoriae. In LOV1’s presence, victorin binding to TRX-h5 activates LOV1 and elicits a resistance-like response that confers disease susceptibility. We propose victorin is or mimics a conventional pathogen virulence effector that was defeated by LOV1 and confers virulence to C. victoriae solely because it incites defense. PMID:23087001

  11. Parasite Exposure Drives Selective Evolution of Constitutive versus Inducible Defense.

    PubMed

    Westra, Edze R; van Houte, Stineke; Oyesiku-Blakemore, Sam; Makin, Ben; Broniewski, Jenny M; Best, Alex; Bondy-Denomy, Joseph; Davidson, Alan; Boots, Mike; Buckling, Angus

    2015-04-20

    In the face of infectious disease, organisms evolved a range of defense mechanisms, with a clear distinction between those that are constitutive (always active) and those that are inducible (elicited by parasites). Both defense strategies have evolved from each other, but we lack an understanding of the conditions that favor one strategy over the other. While it is hard to generalize about their degree of protection, it is possible to make generalizations about their associated fitness costs, which are commonly detected. By definition, constitutive defenses are always "on," and are therefore associated with a fixed cost, independent of parasite exposure. Inducible defenses, on the other hand, may lack costs in the absence of parasites but become costly when defense is elicited through processes such as immunopathology. Bacteria can evolve constitutive defense against phage by modification/masking of surface receptors, which is often associated with reduced fitness in the absence of phage. Bacteria can also evolve inducible defense using the CRISPR-Cas (clustered regularly interspaced short palindromic repeat, CRISPR associated) immune system, which is typically elicited upon infection. CRISPR-Cas functions by integrating phage sequences into CRISPR loci on the host genome. Upon re-infection, CRISPR transcripts guide cleavage of phage genomes. In nature, both mechanisms are important. Using a general theoretical model and experimental evolution, we tease apart the mechanism that drives their evolution and show that infection risk determines the relative investment in the two arms of defense.

  12. Arabidopsis Sigma Factor Binding Proteins Are Activators of the WRKY33 Transcription Factor in Plant Defense[W

    PubMed Central

    Lai, Zhibing; Li, Ying; Wang, Fei; Cheng, Yuan; Fan, Baofang; Yu, Jing-Quan; Chen, Zhixiang

    2011-01-01

    Necrotrophic pathogens are important plant pathogens that cause many devastating plant diseases. Despite their impact, our understanding of the plant defense response to necrotrophic pathogens is limited. The WRKY33 transcription factor is important for plant resistance to necrotrophic pathogens; therefore, elucidation of its functions will enhance our understanding of plant immunity to necrotrophic pathogens. Here, we report the identification of two WRKY33-interacting proteins, nuclear-encoded SIGMA FACTOR BINDING PROTEIN1 (SIB1) and SIB2, which also interact with plastid-encoded plastid RNA polymerase SIGMA FACTOR1. Both SIB1 and SIB2 contain an N-terminal chloroplast targeting signal and a putative nuclear localization signal, suggesting that they are dual targeted. Bimolecular fluorescence complementation indicates that WRKY33 interacts with SIBs in the nucleus of plant cells. Both SIB1 and SIB2 contain a short VQ motif that is important for interaction with WRKY33. The two VQ motif–containing proteins recognize the C-terminal WRKY domain and stimulate the DNA binding activity of WRKY33. Like WRKY33, both SIB1 and SIB2 are rapidly and strongly induced by the necrotrophic pathogen Botrytis cinerea. Resistance to B. cinerea is compromised in the sib1 and sib2 mutants but enhanced in SIB1-overexpressing transgenic plants. These results suggest that dual-targeted SIB1 and SIB2 function as activators of WRKY33 in plant defense against necrotrophic pathogens. PMID:21990940

  13. Integrated signaling network involving calcium, nitric oxide, and active oxygen species but not mitogen-activated protein kinases in BcPG1-elicited grapevine defenses.

    PubMed

    Vandelle, Elodie; Poinssot, Benoît; Wendehenne, David; Bentéjac, Marc; Alain, Pugin

    2006-04-01

    We have already reported the identification of the endopolygalacturonase 1 (BcPG1) from Botrytis cinerea as a potent elicitor of defense responses in grapevine, independently of its enzymatic activity. The aim of the present study is the analysis of the signaling pathways triggered by BcPG1 in grapevine cells. Our data indicate that BcPG1 induces a Ca2+ entry from the apoplasm, which triggers a phosphorylation-dependent nitric oxide (NO) production via an enzyme probably related to a NO synthase. Then NO is involved in (i) cytosolic calcium homeostasis, by activating Ca2+ release from internal stores and regulating Ca2+ fluxes across the plasma membrane, (ii) plasma membrane potential variation, (iii) the activation of active oxygen species (AOS) production, and (iv) defense gene expression, including phenylalanine ammonia lyase and stilbene synthase, which encode enzymes responsible for phytoalexin biosynthesis. Interestingly enough, mitogen-activated protein kinase (MAPK) activation is independent of this regulation pathway that closely connects Ca2+, NO, and AOS.

  14. Commercializing Defense Technologies and Helping Defense Firms Succeed in Commercial Markets: A Report on the Objectives, Activities, and Accomplishments of the TAP-IN Program

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Technology Access for Product Innovation (TAP-IN), the largest technology deployment project funded by TRP, was competitively selected through a national solicitation for proposals. TAP-IN was created to help companies access and apply defense technologies and help defense-dependent companies enter new commercial markets. Defense technologies included technologies developed by DoD, DOE, NASA, and their contractors. TAP-IN was structured to provide region-based technology access services that were able to draw on technology resources nationwide. TAP-IN provided expert assistance in all stages of the commercialization process from concept through prototype design to capital sourcing and marketing strategy. TAP-IN helped companies locate new technology, identify business partners, secure financing, develop ideas for new products, identify new markets, license technology, solve technical problems, and develop company-specific applications of federal technology. TAP-IN leveraged NASA's existing commercial technology network to create an integrated national network of organizations that assisted companies in every state. In addition to NASA's six regional technology transfer centers (RTTCs), TAP-IN included business and technology development organizations in every state, the Industrial Designers Society of America, and the Federal Laboratory Consortium (FLC).

  15. Obligate Biotroph Pathogens of the Genus Albugo Are Better Adapted to Active Host Defense Compared to Niche Competitors.

    PubMed

    Ruhe, Jonas; Agler, Matthew T; Placzek, Aleksandra; Kramer, Katharina; Finkemeier, Iris; Kemen, Eric M

    2016-01-01

    Recent research suggested that plants behave differently under combined versus single abiotic and biotic stress conditions in controlled environments. While this work has provided a glimpse into how plants might behave under complex natural conditions, it also highlights the need for field experiments using established model systems. In nature, diverse microbes colonize the phyllosphere of Arabidopsis thaliana, including the obligate biotroph oomycete genus Albugo, causal agent of the common disease white rust. Biotrophic, as well as hemibiotrophic plant pathogens are characterized by efficient suppression of host defense responses. Lab experiments have even shown that Albugo sp. can suppress non-host resistance, thereby enabling otherwise avirulent pathogen growth. We asked how a pathogen that is vitally dependent on a living host can compete in nature for limited niche space while paradoxically enabling colonization of its host plant for competitors? To address this question, we used a proteomics approach to identify differences and similarities between lab and field samples of Albugo sp.-infected and -uninfected A. thaliana plants. We could identify highly similar apoplastic proteomic profiles in both infected and uninfected plants. In wild plants, however, a broad range of defense-related proteins were detected in the apoplast regardless of infection status, while no or low levels of defense-related proteins were detected in lab samples. These results indicate that Albugo sp. do not strongly affect immune responses and leave distinct branches of the immune signaling network intact. To validate our findings and to get mechanistic insights, we tested a panel of A. thaliana mutant plants with induced or compromised immunity for susceptibility to different biotrophic pathogens. Our findings suggest that the biotroph pathogen Albugo selectively interferes with host defense under different environmental and competitive pressures to maintain its ecological niche

  16. Obligate Biotroph Pathogens of the Genus Albugo Are Better Adapted to Active Host Defense Compared to Niche Competitors

    PubMed Central

    Ruhe, Jonas; Agler, Matthew T.; Placzek, Aleksandra; Kramer, Katharina; Finkemeier, Iris; Kemen, Eric M.

    2016-01-01

    Recent research suggested that plants behave differently under combined versus single abiotic and biotic stress conditions in controlled environments. While this work has provided a glimpse into how plants might behave under complex natural conditions, it also highlights the need for field experiments using established model systems. In nature, diverse microbes colonize the phyllosphere of Arabidopsis thaliana, including the obligate biotroph oomycete genus Albugo, causal agent of the common disease white rust. Biotrophic, as well as hemibiotrophic plant pathogens are characterized by efficient suppression of host defense responses. Lab experiments have even shown that Albugo sp. can suppress non-host resistance, thereby enabling otherwise avirulent pathogen growth. We asked how a pathogen that is vitally dependent on a living host can compete in nature for limited niche space while paradoxically enabling colonization of its host plant for competitors? To address this question, we used a proteomics approach to identify differences and similarities between lab and field samples of Albugo sp.-infected and -uninfected A. thaliana plants. We could identify highly similar apoplastic proteomic profiles in both infected and uninfected plants. In wild plants, however, a broad range of defense-related proteins were detected in the apoplast regardless of infection status, while no or low levels of defense-related proteins were detected in lab samples. These results indicate that Albugo sp. do not strongly affect immune responses and leave distinct branches of the immune signaling network intact. To validate our findings and to get mechanistic insights, we tested a panel of A. thaliana mutant plants with induced or compromised immunity for susceptibility to different biotrophic pathogens. Our findings suggest that the biotroph pathogen Albugo selectively interferes with host defense under different environmental and competitive pressures to maintain its ecological niche

  17. Mechanism of ascaridole activation in Leishmania.

    PubMed

    Geroldinger, Gerald; Tonner, Matthias; Hettegger, Hubert; Bacher, Markus; Monzote, Lianet; Walter, Martin; Staniek, Katrin; Rosenau, Thomas; Gille, Lars

    2017-03-02

    values for Art. In a heme association assay Asc demonstrated a lower binding affinity to heme than Art. ICP-OES measurements revealed that in LtP the total iron concentrations were twice as high as values in J774 macrophages. Since low molecular iron was important in Asc activation we studied the influence of Asc on the labile iron pool (LIP) in LtP. Low temperature EPR experiments demonstrated that Asc shifts the redox balance of iron in the LIP to its oxidized state. These data demonstrate that univalent cleavage of Asc/Art in LtP is an essential part of their pharmacological mechanism. The structure of the EP determines whether activation by low molecular iron or heme is favored and the availability of these intracellular activators modulates their cytotoxicity. These findings may be helpful for synthesis of new Asc derivatives and understanding the action of EP in other cell types.

  18. DNA and RNA polymerase activity in a Moniliophthora perniciosa mitochondrial plasmid and self-defense against oxidative stress.

    PubMed

    Andrade, B S; Villela-Dias, C; Gomes, D S; Micheli, F; Góes-Neto, A

    2013-06-13

    Moniliophthora perniciosa (Stahel) Aime and Phillips-Mora is a hemibiotrophic basidiomycete (Agaricales, Tricholomataceae) that causes witches' broom disease in cocoa (Theobroma cacao L.). This pathogen carries a stable integrated invertron-type linear plasmid in its mitochondrial genome that encodes viral-like DNA and RNA polymerases related to fungal senescence and longevity. After culturing the fungus and obtaining its various stages of development in triplicate, we carried out total RNA extraction and subsequent complementary DNA synthesis. To analyze DNA and RNA polymerase expression levels, we performed real-time reverse transcriptase polymerase chain reaction for various fungal phases of development. Our results showed that DNA and RNA polymerase gene expression in the primordium phase of M. perniciosa is related to a potential defense mechanism against T. cacao oxidative attack.

  19. Transgenic Expression of the Dicotyledonous Pattern Recognition Receptor EFR in Rice Leads to Ligand-Dependent Activation of Defense Responses

    PubMed Central

    Thomas, Nicolas; Holton, Nicolas; Nekrasov, Vladimir; Ruan, Deling; Canlas, Patrick E.; Daudi, Arsalan; Petzold, Christopher J.; Singan, Vasanth R.; Kuo, Rita; Chovatia, Mansi; Daum, Christopher; Heazlewood, Joshua L.; Zipfel, Cyril; Ronald, Pamela C.

    2015-01-01

    Plant plasma membrane localized pattern recognition receptors (PRRs) detect extracellular pathogen-associated molecules. PRRs such as Arabidopsis EFR and rice XA21 are taxonomically restricted and are absent from most plant genomes. Here we show that rice plants expressing EFR or the chimeric receptor EFR::XA21, containing the EFR ectodomain and the XA21 intracellular domain, sense both Escherichia coli- and Xanthomonas oryzae pv. oryzae (Xoo)-derived elf18 peptides at sub-nanomolar concentrations. Treatment of EFR and EFR::XA21 rice leaf tissue with elf18 leads to MAP kinase activation, reactive oxygen production and defense gene expression. Although expression of EFR does not lead to robust enhanced resistance to fully virulent Xoo isolates, it does lead to quantitatively enhanced resistance to weakly virulent Xoo isolates. EFR interacts with OsSERK2 and the XA21 binding protein 24 (XB24), two key components of the rice XA21-mediated immune response. Rice-EFR plants silenced for OsSERK2, or overexpressing rice XB24 are compromised in elf18-induced reactive oxygen production and defense gene expression indicating that these proteins are also important for EFR-mediated signaling in transgenic rice. Taken together, our results demonstrate the potential feasibility of enhancing disease resistance in rice and possibly other monocotyledonous crop species by expression of dicotyledonous PRRs. Our results also suggest that Arabidopsis EFR utilizes at least a subset of the known endogenous rice XA21 signaling components. PMID:25821973

  20. Transgenic expression of the dicotyledonous pattern recognition receptor EFR in rice leads to ligand-dependent activation of defense responses

    DOE PAGES

    Schwessinger, Benjamin; Bahar, Ofir; Thomas, Nicolas; ...

    2015-03-30

    Plant plasma membrane localized pattern recognition receptors (PRRs) detect extracellular pathogen-associated molecules. PRRs such as Arabidopsis EFR and rice XA21 are taxonomically restricted and are absent from most plant genomes. Here we show that rice plants expressing EFR or the chimeric receptor EFR::XA21, containing the EFR ectodomain and the XA21 intracellular domain, sense both Escherichia coli- and Xanthomonas oryzae pv. oryzae (Xoo)-derived elf18 peptides at sub-nanomolar concentrations. Treatment of EFR and EFR::XA21 rice leaf tissue with elf18 leads to MAP kinase activation, reactive oxygen production and defense gene expression. Although expression of EFR does not lead to robust enhanced resistancemore » to fully virulent Xoo isolates, it does lead to quantitatively enhanced resistance to weakly virulent Xoo isolates. EFR interacts with OsSERK2 and the XA21 binding protein 24 (XB24), two key components of the rice XA21-mediated immune response. Rice-EFR plants silenced for OsSERK2, or overexpressing rice XB24 are compromised in elf18-induced reactive oxygen production and defense gene expression indicating that these proteins are also important for EFR-mediated signaling in transgenic rice. Taken together, our results demonstrate the potential feasibility of enhancing disease resistance in rice and possibly other monocotyledonous crop species by expression of dicotyledonous PRRs. Our results also suggest that Arabidopsis EFR utilizes at least a subset of the known endogenous rice XA21 signaling components.« less

  1. Influence of mechanical activation of steel powder on its properties

    NASA Astrophysics Data System (ADS)

    Vaulina, O. Yu; Darenskaia, E. A.; Myachin, Y. V.; Vasilyeva, I. E.; Kulkov, S. N.

    2017-02-01

    It has been studied properties of stainless steel based powders after mechanical activation using planetary ball milling technique. It have been shown that after one minute mechanical activation porosity of sintered steel is less than 5%, which is less than the porosity of the sintered steel powder without mechanical activation. The sample without activation has austenite state, which changes after activation toaustenite and ferrite mixtures. X-ray analysis confirmed that the mechanical activation leads to a change in the phase state of the samples: the samples without activation of the FCC structure (γ-Fe), after activation - FCC (γ-Fe) and BCC (α-Fe). The hardness increases at increasing activation time from 800 MPa for the sample without mechanical activation to 1250 MPa for the sample with the activation time of 10 minutes.

  2. Induction of multixenobiotic defense mechanisms in resistant Daphnia magna clones as a general cellular response to stress.

    PubMed

    Jordão, Rita; Campos, Bruno; Lemos, Marco F L; Soares, Amadeu M V M; Tauler, Romà; Barata, Carlos

    2016-06-01

    Multixenobiotic resistance mechanisms (MXR) were recently identified in Daphnia magna. Previous results characterized gene transcripts of genes encoding and efflux activities of four putative ABCB1 and ABCC transporters that were chemically induced but showed low specificity against model transporter substrates and inhibitors, thus preventing us from distinguishing between activities of different efflux transporter types. In this study we report on the specificity of induction of ABC transporters and of the stress protein hsp70 in clones selected to be genetically resistant to ABCB1 chemical substrates. Clones resistant to mitoxantrone, ivermectin and pentachlorophenol showed distinctive transcriptional responses of transporter protein coding genes and of putative transporter dye activities. Expression of hsp70 proteins also varied across resistant clones. Clones resistant to mitoxantrone and pentachlorophenol showed high constitutive levels of hsp70. Transcriptional levels of the abcb1 gene transporter and of putative dye transporter activity were also induced to a greater extent in the pentachlorophenol resistant clone. Observed higher dye transporter activities in individuals from clones resistant to mitoxantrone and ivermectin were unrelated with transcriptional levels of the studied four abcc and abcb1 transporter genes. These findings suggest that Abcb1 induction in D. magna may be a part of a general cellular stress response.

  3. Heart‐Specific Overexpression of Choline Acetyltransferase Gene Protects Murine Heart Against Ischemia Through Hypoxia‐Inducible Factor‐1α–Related Defense Mechanisms

    PubMed Central

    Kakinuma, Yoshihiko; Tsuda, Masayuki; Okazaki, Kayo; Akiyama, Tsuyoshi; Arikawa, Mikihiko; Noguchi, Tatsuya; Sato, Takayuki

    2013-01-01

    Background Murine and human ventricular cardiomyocytes rich in acetylcholine (Ach) receptors are poorly innervated by the vagus, compared with whole ventricular innervation by the adrenergic nerve. However, vagal nerve stimulation produces a favorable outcome even in the murine heart, despite relatively low ventricular cholinergic nerve density. Such a mismatch and missing link suggest the existence of a nonneuronal cholinergic system in ventricular myocardium. Methods and Results To examine the role of the nonneuronal cardiac cholinergic system, we generated choline acetyltransferase (ChAT)–expressing cells and heart‐specific ChAT transgenic (ChAT‐tg) mice. Compared with cardiomyocytes of wild‐type (WT) mice, those of the ChAT‐tg mice had high levels of ACh and hypoxia‐inducible factor (HIF)‐1α protein and augmented glucose uptake. These phenotypes were also reproduced by ChAT‐overexpressing cells, which utilized oxygen less. Before myocardial infarction (MI), the WT and ChAT‐tg mice showed similar hemodynamics; after MI, however, the ChAT‐tg mice had better survival than did the WT mice. In the ChAT‐tg hearts, accelerated angiogenesis at the ischemic area, and accentuated glucose utilization prevented post‐MI remodeling. The ChAT‐tg heart was more resistant to ischemia–reperfusion injury than was the WT heart. Conclusions These results suggest that the activated cardiac ACh‐HIF‐1α cascade improves survival after MI. We conclude that de novo synthesis of ACh in cardiomyocytes is a pivotal mechanism for self‐defense against ischemia. PMID:23525439

  4. Vaginismus, a component of a general defensive reaction. an investigation of pelvic floor muscle activity during exposure to emotion-inducing film excerpts in women with and without vaginismus.

    PubMed

    van der Velde, J; Laan, E; Everaerd, W

    2001-01-01

    This study investigates the mechanism underlying vaginismus, which may be part of a general defense mechanism. Exposure to a threatening situation will evoke an increase in muscle activity. This muscle reaction will not be restricted to the pelvic floor but will also occur in postural muscles, such as in the trapezius region. Women with and without vaginismus were exposed to four stimuli: excerpts from threatening, erotic, neutral and sexual-threatening films. Subjects were 45 physician- or self-referred patients with vaginismus and 32 controls with no sexual or pelvic floor complaints. The activity of the pelvic floor muscles and of the muscles in the trapezius region was recorded with surface electrodes. There were no differences between women with and without vaginistic reactions. EMG measurement of both the pelvic floor muscles and the trapezius muscle showed an increase in muscle activity during the threatening and sexual-threatening excerpts in women with and without vaginismus. This increase of involuntary pelvic floor muscle activity is part of a general defense mechanism that occurs during exposure to threatening situations. This reaction is not restricted to a situation with a sexual content. The results of this study shed new light on the concept of vaginismus as a primarily sexual dysfunction.

  5. ATL9, a RING Zinc Finger Protein with E3 Ubiquitin Ligase Activity Implicated in Chitin- and NADPH Oxidase-Mediated Defense Responses

    PubMed Central

    Berrocal-Lobo, Marta; Stone, Sophia; Yang, Xin; Antico, Jay; Callis, Judy; Ramonell, Katrina M.; Somerville, Shauna

    2010-01-01

    Pathogen associated molecular patterns (PAMPs) are signals detected by plants that activate basal defenses. One of these PAMPs is chitin, a carbohydrate present in the cell walls of fungi and in insect exoskeletons. Previous work has shown that chitin treatment of Arabidopsis thaliana induced defense-related genes in the absence of a pathogen and that the response was independent of the salicylic acid (SA), jasmonic acid (JA) and ethylene (ET) signaling pathways. One of these genes is ATL9 ( = ATL2G), which encodes a RING zinc-finger like protein. In the current work we demonstrate that ATL9 has E3 ubiquitin ligase activity and is localized to the endoplasmic reticulum. The expression pattern of ATL9 is positively correlated with basal defense responses against Golovinomyces cichoracearum, a biotrophic fungal pathogen. The basal levels of expression and the induction of ATL9 by chitin, in wild type plants, depends on the activity of NADPH oxidases suggesting that chitin-mediated defense response is NADPH oxidase dependent. Although ATL9 expression is not induced by treatment with known defense hormones (SA, JA or ET), full expression in response to chitin is compromised slightly in mutants where ET- or SA-dependent signaling is suppressed. Microarray analysis of the atl9 mutant revealed candidate genes that appear to act downstream of ATL9 in chitin-mediated defenses. These results hint at the complexity of chitin-mediated signaling and the potential interplay between elicitor-mediated signaling, signaling via known defense pathways and the oxidative burst. PMID:21203445

  6. Perception of soft mechanical stress in Arabidopsis leaves activates disease resistance

    PubMed Central

    2013-01-01

    Background In a previous study we have shown that wounding of Arabidopsis thaliana leaves induces a strong and transient immunity to Botrytis cinerea, the causal agent of grey mould. Reactive oxygen species (ROS) are formed within minutes after wounding and are required for wound–induced resistance to B. cinerea. Results In this study, we have further explored ROS and resistance to B. cinerea in leaves of A. thaliana exposed to a soft form of mechanical stimulation without overt tissue damage. After gentle mechanical sweeping of leaf surfaces, a strong resistance to B. cinerea was observed. This was preceded by a rapid change in calcium concentration and a release of ROS, accompanied by changes in cuticle permeability, induction of the expression of genes typically associated with mechanical stress and release of biologically active diffusates from the surface. This reaction to soft mechanical stress (SMS) was fully independent of jasmonate (JA signaling). In addition, leaves exposed soft mechanical stress released a biologically active product capable of inducing resistance to B. cinerea in wild type control leaves. Conclusion Arabidopsis can detect and convert gentle forms of mechanical stimulation into a strong activation of defense against the virulent fungus B. cinerea. PMID:24033927

  7. Inhibition of sunfish feeding by defensive steroids from aquatic beetles: Structure activity relationships.

    PubMed

    Gerhart, D J; Bondura, M E; Commito, J A

    1991-07-01

    The vertebrate hormone deoxycorticosterone is the most commonly occurring component of defensive secretions from aquatic beetles in the family Dytiscidae. Deoxycorticosterone and the structurally related steroids pregn-4-en-20α:-ol-3-one and pregn-4-en-20β-ol-3-one were tested for their ability to inhibit feeding by bluegill sunfish,Lepomis macrochirus, in laboratory assays. Deoxycorticosterone at oral doses of 660μg (2 x 10(-6) mol) per pellet caused 94% inhibition in the acceptance of artificial food pellets. At the same molar dosage, pregn-4-en-20α-ol-3-one inhibited food consumption by 58%, while its epimer, pregn-4-en-20β-ol-3-one, did not significantly inhibit feeding. These results indicate that specific stereochemical conditions must be satisfied for the pregnenes to be noxious toL. macrochirus and suggest the existence of a receptor-ligand interaction. The potency of the three steroids in assays of feeding inhibition contradicts earlier results based on toxicity and anesthetic assays in which fish were immersed in solutions of steroids.

  8. Disaster relief activities of the Japan self-defense force following the Great East Japan Earthquake.

    PubMed

    Nishiyama, Yasumasa

    2014-06-01

    Cooperation between civilian and military forces, including the Japan Self-Defense Force (JSDF), enabled wide-ranging disaster relief after the Great East Japan Earthquake. Nevertheless, many preventable fatalities occurred, particularly related to an inability to treat chronic disease, indicating the need to plan for the provision of long-term medical aid after natural disasters in stricken areas and evacuation shelters. To assist in this effort, this report (1) provides an overview of the consequences of the medical response to the Great East Japan Earthquake, the largest natural disaster ever to hit Japan, focusing on the role and actions of the JSDF; (2) discusses the lessons learned regarding the provision of medical aid and management by the JSDF after this disaster, looking at the special challenges of meeting the needs of a rapidly aging population in a disaster situation; and (3) provides recommendations for the development of strategies for the long-term medical aid and support after natural disasters, especially with regard to the demographics of the Japanese population.

  9. [Activity of lipid peroxidation processes and the condition of antioxidative defense system in children with rheumatic fever].

    PubMed

    Shanidze, E; Zhvania, M

    2005-10-01

    Aim of study consists of establishing of some clinical-biological correlates for rheumatic fever (RF) in children, namely correlations between clinical status and lipoperoxidation products -- malonidialdehide (MDA) and antioxidative enzymes in the blood. In the neutralization process of superoxside anions ceruloplazmin (CP), catalase (CAT) and transferin (TF) are key antioxidant enzymes (AOE) of antioxidative defense system (AOD). We studied 38 patients 3-15 years of age with different variants of RF. We measured the levels of MDA, CAT, CP, TF in the plasma in patients with acute rheumatic fever (ARF) and chronic rheumatic heart disease (CRHD). In all of our cases AOE (CAT, CP, TF) were high at time of diagnosis, concomitant with increased MDA and inflammatory tests. Our study revealed intensified activity of AOD enzymes in children with RF.

  10. Induction of DIMBOA accumulation and systemic defense responses as a mechanism of enhanced resistance of mycorrhizal corn (Zea mays L.) to sheath blight.

    PubMed

    Song, Yuan Yuan; Cao, Man; Xie, Li Jun; Liang, Xiao Ting; Zeng, Ren Sen; Su, Yi Juan; Huang, Jing Hua; Wang, Rui Long; Luo, Shi Ming

    2011-11-01

    Arbuscular mycorrhizas are the most important symbioses in terrestrial ecosystems and they enhance the plant defense against numerous soil-borne pathogenic fungi and nematodes. Two corn (Zea mays) varieties, Gaoyou-115 that is susceptible to sheath blight disease caused by Rhizoctonia solani and Yuenong-9 that is resistant, were used for mycorrhizal inoculation in this study. Pre-inoculation of susceptible Gaoyou-115 with arbuscular mycorrhizal fungus (AMF) Glomus mosseae significantly reduced the disease incidence and disease severity of sheath blight of corn. HPLC analysis showed that AMF inoculation led to significant increase in 2,4-dihydroxy-7-methoxy-2 H-1,4-benzoxazin-3(4 H)-one (DIMBOA) accumulation in the roots of both corn varieties and in leaves of resistant Yuenong-9. R. solani inoculation alone did not result in accumulation of DIMBOA in both roots and leaves of the two corn varieties. Our previous study showed that DIMBOA strongly inhibited mycelial growth of R. solani in vitro. Real-time PCR analysis showed that mycorrhizal inoculation itself did not affect the transcripts of most genes tested. However, pre-inoculation with G. mosseae induced strong responses of three defense-related genes PR2a, PAL, and AOS, as well as BX9, one of the key genes in DIMBOA biosynthesis pathway, in the leaves of corn plants of both Yuenong-9 and Gaoyou-115 after the pathogen attack. Induction of defense responses in pre-inoculated plants was much higher and quicker than that in non-inoculated plants upon R. solani infection. These results indicate that induction of accumulation of DIMBOA, an important phytoalexin in corn, and systemic defense responses by AMF, plays a vital role in enhanced disease resistance of mycorrhizal plants of corn against sheath blight. This study also suggests that priming is an important mechanism in mycorrhiza-induced resistance.

  11. Combined activation of the energy and cellular-defense pathways may explain the potent anti-senescence activity of methylene blue.

    PubMed

    Atamna, Hani; Atamna, Wafa; Al-Eyd, Ghaith; Shanower, Gregory; Dhahbi, Joseph M

    2015-12-01

    Methylene blue (MB) delays cellular senescence, induces complex-IV, and activates Keap1/Nrf2; however, the molecular link of these effects to MB is unclear. Since MB is redox-active, we investigated its effect on the NAD/NADH ratio in IMR90 cells. The transient increase in NAD/NADH observed in MB-treated cells triggered an investigation of the energy regulator AMPK. MB induced AMPK phosphorylation in a transient pattern, which was followed by the induction of PGC1α and SURF1: both are inducers of mitochondrial and complex-IV biogenesis. Subsequently MB-treated cells exhibited >100% increase in complex-IV activity and a 28% decline in cellular oxidants. The telomeres erosion rate was also significantly lower in MB-treated cells. A previous research suggested that the pattern of AMPK activation (i.e., chronic or transient) determines the AMPK effect on cell senescence. We identified that the anti-senescence activity of MB (transient activator) was 8-times higher than that of AICAR (chronic activator). Since MB lacked an effect on cell cycle, an MB-dependent change to cell cycle is unlikely to contribute to the anti-senescence activity. The current findings in conjunction with the activation of Keap1/Nrf2 suggest a synchronized activation of the energy and cellular defense pathways as a possible key factor in MB's potent anti-senescence activity.

  12. BQ123 Stimulates Skeletal Muscle Antioxidant Defense via Nrf2 Activation in LPS-Treated Rats

    PubMed Central

    Jeleń, Agnieszka; Żebrowska, Marta; Balcerczak, Ewa; Gorąca, Anna

    2016-01-01

    Little is understood of skeletal muscle tissue in terms of oxidative stress and inflammation. Endothelin-1 is an endogenous, vasoconstrictive peptide which can induce overproduction of reactive oxygen species and proinflammatory cytokines. The aim of this study was to evaluate whether BQ123, an endothelin-A receptor antagonist, influences the level of TNF-α, IL-6, SOD-1, HO-1, Nrf2 mRNA, and NF-κB subunit RelA/p65 mRNA in the femoral muscle obtained from endotoxemic rats. Male Wistar rats were divided into 4 groups (n = 6) and received iv (1) saline (control), (2) LPS (15 mg/kg), (3) BQ123 (1 mg/kg), (4) BQ123 (1 mg/kg), and LPS (15 mg/kg, resp.) 30 min later. Injection of LPS led to significant increase in levels of RelA/p65 mRNA, TNF-α, and IL-6, while content of SOD-1, HO-1, and Nrf2 mRNA was unchanged. Administration of BQ123 prior to LPS challenge resulted in a significant reduction in RelA/p65 mRNA, TNF-α, and IL-6 levels, as well as markedly elevated concentrations of SOD-1, HO-1, and Nrf2 mRNA. BQ123 appears to enhance antioxidant defense and prevent production of TNF-α and IL-6 in skeletal muscle of LPS-treated rat. In conclusion, endothelin-A receptor antagonism exerts significant impact on the skeletal muscle favouring anti-inflammatory effects and protection against oxidative stress. PMID:26823945

  13. STIM1 calcium sensor is required for activation of the phagocyte oxidase during inflammation and host defense.

    PubMed

    Zhang, Hong; Clemens, Regina A; Liu, Fengchun; Hu, Yongmei; Baba, Yoshihiro; Theodore, Pierre; Kurosaki, Tomohiro; Lowell, Clifford A

    2014-04-03

    The stromal-interacting molecule 1 (STIM1) is a potent sensor of intracellular calcium, which in turn regulates entry of external calcium through plasma membrane channels to affect immune cell activation. Although the contribution of STIM1 to calcium signaling in lymphocytes has been well studied, the role of this protein in neutrophil-mediated inflammation and host defense is unknown. We report that STIM1-deficient murine neutrophils show loss of store-operated calcium entry (SOCE) in response to both soluble ligands that activate G-proteins as well as Fcγ-receptor or integrin ligation that activates tyrosine kinase signaling. This results in modest defects in phagocytosis and degranulation responses but a profound block in superoxide production by the phagocyte oxidase. We trace the primary intracellular target of calcium to be protein kinase C isoforms α and β (PKCα and PKCβ), which in turn phosphorylate subunits of the oxidase leading to superoxide production. In vivo the loss of SOCE in stim1(-/-) chimeric mice results in marked susceptibility to bacterial infections but also protection from tissue injury in hepatic ischemia/reperfusion injury. These results demonstrate the critical role of STIM1-mediated SOCE and define major protein targets of calcium signaling in neutrophil activation during inflammatory disease.

  14. Does strategic defense breed offense

    SciTech Connect

    York, H.

    1987-01-01

    The author examines the question of whether strategic defense activity, in any form, stimulates a related offensive activity. The author studies four post-World II efforts of the superpowers to develop and deploy strategic defenses. The author then derives lessons from those cases that he applies to his analysis of President Reagan's Strategic Defense Initiative. Commentaries on the author's analysis are provided by four scholars.

  15. [Influence of ionizing radiation on activity of enzymes of antioxidant defense of Paecilomyces lilaclvus (Thom) Samson].

    PubMed

    Tuhaĭ, T I

    2011-01-01

    The level of activity of antioxidant protection enzymes (superoxide dismutase, catalase and peroxidase) under exposure to ionizing radiation and without it in strain Paecilomyces lilacinus, showing radioadaptive properties, and in control one has been investigated. It has been established that the researched strains are characterized by the high level activity of superoxide dismutase (200-800 AU/mg protein), extracellular and intracellular catalase (0.02-40 mmol min(-1) mg(-1) protein) and peroxidase (0.2-4 mmol min(-1) mg(-1) protein). Ionizing radiation was the inducer of significant changes in antioxidant enzyme activity of the control strain (from the lack of influence to the change of activity by an order) and showed considerably less influence on their activity in the strain, showing radioadaptive properties (the activity changes by 40-50%). The complex response of antioxidant enzymes in investigated strains under the exposure to ionizing radiation has been revealed.

  16. RpoHII Activates Oxidative-Stress Defense Systems and Is Controlled by RpoE in the Singlet Oxygen-Dependent Response in Rhodobacter sphaeroides▿ †

    PubMed Central

    Nuss, Aaron M.; Glaeser, Jens; Klug, Gabriele

    2009-01-01

    Photosynthetic organisms need defense systems against photooxidative stress caused by the generation of highly reactive singlet oxygen (1O2). Here we show that the alternative sigma factor RpoHII is required for the expression of important defense factors and that deletion of rpoHII leads to increased sensitivity against exposure to 1O2 and methylglyoxal in Rhodobacter sphaeroides. The gene encoding RpoHII is controlled by RpoE, and thereby a sigma factor cascade is constituted. We provide the first in vivo study that identifies genes controlled by an RpoHII-type sigma factor, which is widely distributed in the Alphaproteobacteria. RpoHII-dependent genes encode oxidative-stress defense systems, including proteins for the degradation of methylglyoxal, detoxification of peroxides, 1O2 scavenging, and redox and iron homeostasis. Our experiments indicate that glutathione (GSH)-dependent mechanisms are involved in the defense against photooxidative stress in photosynthetic bacteria. Therefore, we conclude that systems pivotal for the organism's defense against photooxidative stress are strongly dependent on GSH and are specifically recognized by RpoHII in R. sphaeroides. PMID:18978062

  17. Early Disruption of Maternal–Zygotic Interaction and Activation of Defense-Like Responses in Arabidopsis Interspecific Crosses[C][W][OPEN

    PubMed Central

    Burkart-Waco, Diana; Ngo, Kathie; Dilkes, Brian; Josefsson, Caroline; Comai, Luca

    2013-01-01

    Seed death resulting from hybridization between Arabidopsis thaliana and Arabidopsis arenosa has complex genetic determination and involves deregulation 5 to 8 d after pollination (DAP) of AGAMOUS-LIKE genes and retroelements. To identify causal mechanisms, we compared transcriptomes of compatible and incompatible hybrids and parents at 3 DAP. Hybrids misexpressed endosperm and seed coat regulators and hyperactivated genes encoding ribosomal, photosynthetic, stress-related, and immune response proteins. Regulatory disruption was more severe in Columbia-0 hybrids than in C24 hybrids, consistent with the degree of incompatibility. Maternal loss-of-function alleles for endosperm growth factor TRANSPARENT TESTA GLABRA2 and HAIKU1 and defense response regulators NON-EXPRESSOR OF PATHOGENESIS RELATED1 and SALICYLIC ACID INDUCTION-DEFICIENT2 increased hybrid seed survival. The activation of presumed POLYCOMB REPRESSIVE COMPLEX (PRC) targets, together with a 20-fold reduction in expression of FERTILIZATION INDEPENDENT SEED2, indicated a PRC role. Proximity to transposable elements affected natural variation for gene regulation, but transposon activation did not differ from controls. Collectively, this investigation provides candidates for multigenic orchestration of the incompatibility response through disruption of endosperm development, a novel role for communication between endosperm and maternal tissues and for pathways previously connected to immunity, but, surprisingly, does not identify a role for transposons. PMID:23898028

  18. The extracellular adherence protein (Eap) of Staphylococcus aureus inhibits wound healing by interfering with host defense and repair mechanisms.

    PubMed

    Athanasopoulos, Athanasios N; Economopoulou, Matina; Orlova, Valeria V; Sobke, Astrid; Schneider, Darius; Weber, Holger; Augustin, Hellmut G; Eming, Sabine A; Schubert, Uwe; Linn, Thomas; Nawroth, Peter P; Hussain, Muzaffar; Hammes, Hans-Peter; Herrmann, Mathias; Preissner, Klaus T; Chavakis, Triantafyllos

    2006-04-01

    Staphylococcus aureus is a major human pathogen interfering with host-cell functions. Impaired wound healing is often observed in S aureus-infected wounds, yet, the underlying mechanisms are poorly defined. Here, we identify the extracellular adherence protein (Eap) of S aureus to be responsible for impaired wound healing. In a mouse wound-healing model wound closure was inhibited in the presence of wild-type S aureus and this effect was reversible when the wounds were incubated with an isogenic Eap-deficient strain. Isolated Eap also delayed wound closure. In the presence of Eap, recruitment of inflammatory cells to the wound site as well as neovascularization of the wound were prevented. In vitro, Eap significantly reduced intercellular adhesion molecule 1 (ICAM-1)-dependent leukocyte-endothelial interactions and diminished the consequent activation of the proinflammatory transcription factor nuclear factor kappaB (NFkappaB) in leukocytes associated with a decrease in expression of tissue factor. Moreover, Eap blocked alphav-integrin-mediated endothelial-cell migration and capillary tube formation, and neovascularization in matrigels in vivo. Collectively, the potent anti-inflammatory and antiangiogenic properties of Eap provide an underlying mechanism that may explain the impaired wound healing in S aureus-infected wounds. Eap may also serve as a lead compound for new anti-inflammatory and antiangiogenic therapies in several pathologies.

  19. Transgenic expression of the dicotyledonous pattern recognition receptor EFR in rice leads to ligand-dependent activation of defense responses

    SciTech Connect

    Schwessinger, Benjamin; Bahar, Ofir; Thomas, Nicolas; Holton, Nicolas; Nekrasov, Vladimir; Ruan, Deling; Canlas, Patrick E.; Daudi, Arsalan; Petzold, Christopher J.; Singan, Vasanth R.; Kuo, Rita; Chovatia, Mansi; Daum, Christopher; Heazlewood, Joshua L.; Zipfel, Cyril; Ronald, Pamela C.

    2015-03-30

    Plant plasma membrane localized pattern recognition receptors (PRRs) detect extracellular pathogen-associated molecules. PRRs such as Arabidopsis EFR and rice XA21 are taxonomically restricted and are absent from most plant genomes. Here we show that rice plants expressing EFR or the chimeric receptor EFR::XA21, containing the EFR ectodomain and the XA21 intracellular domain, sense both Escherichia coli- and Xanthomonas oryzae pv. oryzae (Xoo)-derived elf18 peptides at sub-nanomolar concentrations. Treatment of EFR and EFR::XA21 rice leaf tissue with elf18 leads to MAP kinase activation, reactive oxygen production and defense gene expression. Although expression of EFR does not lead to robust enhanced resistance to fully virulent Xoo isolates, it does lead to quantitatively enhanced resistance to weakly virulent Xoo isolates. EFR interacts with OsSERK2 and the XA21 binding protein 24 (XB24), two key components of the rice XA21-mediated immune response. Rice-EFR plants silenced for OsSERK2, or overexpressing rice XB24 are compromised in elf18-induced reactive oxygen production and defense gene expression indicating that these proteins are also important for EFR-mediated signaling in transgenic rice. Taken together, our results demonstrate the potential feasibility of enhancing disease resistance in rice and possibly other monocotyledonous crop species by expression of dicotyledonous PRRs. Our results also suggest that Arabidopsis EFR utilizes at least a subset of the known endogenous rice XA21 signaling components.

  20. Unbalanced Activation of Glutathione Metabolic Pathways Suggests Potential Involvement in Plant Defense against the Gall Midge Mayetiola destructor in Wheat

    PubMed Central

    Liu, Xuming; Zhang, Shize; Whitworth, R. Jeff; Stuart, Jeffrey J.; Chen, Ming-Shun

    2015-01-01

    Glutathione, γ-glutamylcysteinylglycine, exists abundantly in nearly all organisms. Glutathione participates in various physiological processes involved in redox reactions by serving as an electron donor/acceptor. We found that the abundance of total glutathione increased up to 60% in resistant wheat plants within 72 hours following attack by the gall midge Mayetiola destructor, the Hessian fly. The increase in total glutathione abundance, however, is coupled with an unbalanced activation of glutathione metabolic pathways. The activity and transcript abundance of glutathione peroxidases, which convert reduced glutathione (GSH) to oxidized glutathione (GSSG), increased in infested resistant plants. However, the enzymatic activity and transcript abundance of glutathione reductases, which convert GSSG back to GSH, did not change. This unbalanced regulation of the glutathione oxidation/reduction cycle indicates the existence of an alternative pathway to regenerate GSH from GSSG to maintain a stable GSSG/GSH ratio. Our data suggest the possibility that GSSG is transported from cytosol to apoplast to serve as an oxidant for class III peroxidases to generate reactive oxygen species for plant defense against Hessian fly larvae. Our results provide a foundation for elucidating the molecular processes involved in glutathione-mediated plant resistance to Hessian fly and potentially other pests as well. PMID:25627558

  1. Platelet Activation: The Mechanisms and Potential Biomarkers

    PubMed Central

    Yun, Seong-Hoon; Sim, Eun-Hye; Goh, Ri-Young; Park, Joo-In

    2016-01-01

    Beyond hemostasis and thrombosis, an increasing number of studies indicate that platelets play an integral role in intercellular communication, mediating inflammatory and immunomodulatory activities. Our knowledge about how platelets modulate inflammatory and immunity has greatly improved in recent years. In this review, we discuss recent advances in the pathways of platelet activation and potential application of platelet activation biomarkers to diagnosis and prediction of disease states. PMID:27403440

  2. Department of Defense In-House RDT&E Activities. Management Analysis Report: Department of the Army, Department of the Navy, Department of the Air Force

    DTIC Science & Technology

    1985-10-30

    RESEARCH INSTITUTE OF CHEMICAL DEFENSE ..................... 43 MEDICAL RESEARCH INSTITUTE OF INFECTIOUS DISEASES .................. 44 MISSILE...COMPUTER SUPPORT AVAILABLE.TEMPERATURES TO -50 DEG FAHR CONNON. 16 INSTALLATION: COMBAT SYSTEMS TEST ACTIVITY ABERDEEN PVG GRDMD CDR. COL RONALD V. HITE...FROM CHEM AGENT & VECTOR BORN DISEASE ; MAMMALIAN & IN VITRO TOXICOLOGY; FORWARD AREA CASUALTY CARE ... CURRENT IMPORTANT PROGRAMS DFTERMINATION OF SAFE

  3. Clustered regularly interspaced short palindromic repeats (CRISPRs): the hallmark of an ingenious antiviral defense mechanism in prokaryotes.

    PubMed

    Al-Attar, Sinan; Westra, Edze R; van der Oost, John; Brouns, Stan J J

    2011-04-01

    Many prokaryotes contain the recently discovered defense system against mobile genetic elements. This defense system contains a unique type of repetitive DNA stretches, termed Clustered Regularly Interspaced Short Palindromic Repeats (CRISPRs). CRISPRs consist of identical repeated DNA sequences (repeats), interspaced by highly variable sequences referred to as spacers. The spacers originate from either phages or plasmids and comprise the prokaryotes' 'immunological memory'. CRISPR-associated (cas) genes encode conserved proteins that together with CRISPRs make-up the CRISPR/Cas system, responsible for defending the prokaryotic cell against invaders. CRISPR-mediated resistance has been proposed to involve three stages: (i) CRISPR-Adaptation, the invader DNA is encountered by the CRISPR/Cas machinery and an invader-derived short DNA fragment is incorporated in the CRISPR array. (ii) CRISPR-Expression, the CRISPR array is transcribed and the transcript is processed by Cas proteins. (iii) CRISPR-Interference, the invaders' nucleic acid is recognized by complementarity to the crRNA and neutralized. An application of the CRISPR/Cas system is the immunization of industry-relevant prokaryotes (or eukaryotes) against mobile-genetic invasion. In addition, the high variability of the CRISPR spacer content can be exploited for phylogenetic and evolutionary studies. Despite impressive progress during the last couple of years, the elucidation of several fundamental details will be a major challenge in future research.

  4. Department of Defense Survey of Health Related Behaviors Among Active Duty Military Personnel

    DTIC Science & Technology

    2009-09-01

    Assessment Program (DLAP), which incorporates the active duty health behaviors study and expands the scope to include the National Guard and Reserves, as...well as other special studies . Findings from the program provide information on the fitness of the force, including estimates of alcohol, drug, and...first to include Coast Guard personnel. The study has three broad aims for active duty military personnel: continue to assess the nature, extent, and

  5. Priming maize resistance by its neighbors: activating 1,4-benzoxazine-3-ones synthesis and defense gene expression to alleviate leaf disease.

    PubMed

    Ding, Xupo; Yang, Min; Huang, Huichuan; Chuan, Youcong; He, Xiahong; Li, Chengyun; Zhu, Youyong; Zhu, Shusheng

    2015-01-01

    Plant disease can be effectively suppressed in intercropping systems. Our previous study demonstrated that neighboring maize plants can restrict the spread of soil-borne pathogens of pepper plants by secreting defense compounds into the soil. However, whether maize plant can receive benefits from its neighboring pepper plants in an intercropping system is little attention. We examined the effects of maize roots treated with elicitors from the pepper pathogen Phytophthora capsici and pepper root exudates on the synthesis of 1,4-benzoxazine-3-ones (BXs), the expression of defense-related genes in maize, and their ability to alleviate the severity of southern corn leaf blight (SCLB) caused by Bipolaris maydis. We found that SCLB was significantly reduced after the above treatments. The contents of 1,4-benzoxazine-3-ones (BXs: DIBOA, DIMBOA, and MBOA) and the expression levels of BX synthesis and defense genes in maize roots and shoots were up-regulated. DIMBOA and MBOA effectively inhibited the mycelium growth of Bipolaris maydis at physiological concentrations in maize shoots. Further studies suggested that the defense related pathways or genes in maize roots and shoots were activated by elicitors from the P. capsici or pepper root exudates. In conclusion, maize increased the levels of BXs and defense gene expression both in roots and shoots after being triggered by root exudates and pathogen from neighboring pepper plants, eventually enhancing its resistance.

  6. Priming maize resistance by its neighbors: activating 1,4-benzoxazine-3-ones synthesis and defense gene expression to alleviate leaf disease

    PubMed Central

    Ding, Xupo; Yang, Min; Huang, Huichuan; Chuan, Youcong; He, Xiahong; Li, Chengyun; Zhu, Youyong; Zhu, Shusheng

    2015-01-01

    Plant disease can be effectively suppressed in intercropping systems. Our previous study demonstrated that neighboring maize plants can restrict the spread of soil-borne pathogens of pepper plants by secreting defense compounds into the soil. However, whether maize plant can receive benefits from its neighboring pepper plants in an intercropping system is little attention. We examined the effects of maize roots treated with elicitors from the pepper pathogen Phytophthora capsici and pepper root exudates on the synthesis of 1,4-benzoxazine-3-ones (BXs), the expression of defense-related genes in maize, and their ability to alleviate the severity of southern corn leaf blight (SCLB) caused by Bipolaris maydis. We found that SCLB was significantly reduced after the above treatments. The contents of 1,4-benzoxazine-3-ones (BXs: DIBOA, DIMBOA, and MBOA) and the expression levels of BX synthesis and defense genes in maize roots and shoots were up-regulated. DIMBOA and MBOA effectively inhibited the mycelium growth of Bipolaris maydis at physiological concentrations in maize shoots. Further studies suggested that the defense related pathways or genes in maize roots and shoots were activated by elicitors from the P. capsici or pepper root exudates. In conclusion, maize increased the levels of BXs and defense gene expression both in roots and shoots after being triggered by root exudates and pathogen from neighboring pepper plants, eventually enhancing its resistance. PMID:26528303

  7. Transforming Defense

    DTIC Science & Technology

    2005-09-01

    or agency each week?” 47 By way of just one example, Madrid’s La Razon reported on September 13 , 2004, that Spain would lose U.S. bases to Portugal...public release, distribution unlimited 13 . SUPPLEMENTARY NOTES 14. ABSTRACT 15. SUBJECT TERMS 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF...DEFENSE 7 responsibilities. The homeland security JOC envisions a layered and comprehensive defense requiring geographical and functional integra- tion. 13

  8. [Are active neurons a better defense against aging in Alzheimer's disease?].

    PubMed

    Lucassen, P J; van Someren, E J; Swaab, D F

    1998-08-01

    This article deals with the question whether metabolic activity of neurons interferes with their survival during brain aging and Alzheimer's disease (AD). This 'use it or lose it' concept assumes that active neurons have a better chance to survive these conditions. We have monitored activity changes in human hypothalamic nuclei, that show differential survival patterns in aging and AD. The size of the Golgi apparatus (GA) was measured in e.g. the nucleus basalis of Meynert (NBM), that is severely affected in AD, and in the vasopressin (AVP) containing neurons of the supraoptic nucleus (SON) that remain very stable and show no cell loss. In the affected NBM, a strong reduction in activity was found in AD, whereas in the stable SON, an increased activity was present in both conditions. These findings agree with the concept that activation is associated with pronounced stability in aging and AD. Another hypothalamic nucleus is the biological clock (SCN), which is very sensitive to light input. It loses about 35% of its AVP cells in old rats. In order to test the hypothesis that extra stimulation prevents degeneration, the SCN in old rats was activated by means of an increased light input. This could indeed prevent the age-related loss of AVP-neurons in the SCN in low light conditions. Increased light also restored the age-related decreased amplitude in the sleep-wake rhythm. Furthermore, in AD patients, increased amounts of environmental light improved day-night rhythms and reduced behavioural disturbances. These observations are in line with the 'use it or lose it' concept. Furthermore, oxidative damage to the DNA was studied as a) it may accumulate during neuronal aging, and b) activated cells repair their DNA more efficiently. Whereas biochemical measurements of 8OHDG levels were not different in aging or AD, in situ end labeling, that detects fragmented DNA histologically, showed many positive neurons and glial cells in the AD, but not control, hippocampus

  9. Moxibustion activates host defense against herpes simplex virus type I through augmentation of cytokine production.

    PubMed

    Takayama, Yuko; Itoi, Manami; Hamahashi, Takashi; Tsukamoto, Noriyuki; Mori, Kazuya; Morishita, Daisuke; Wada, Kumiko; Amagai, Takashi

    2010-09-01

    Moxibustion is a technique used in traditional oriental medicine, the aim of which is to cure and/or prevent illness by activating a person's ability for self-healing. In this study, we assessed how moxibustion would affect the immune system and whether it would augment protective immunity. Mice were treated with moxibustion at Zusanli (ST36) acupoints; we analyzed mortality and cytokine activity in sera after infection with herpes simplex virus type 1 (HSV-1), and cytokine gene expression in the skin and the spleen without a virus challenge. Our study demonstrates that pretreatment of BALB/c mice with moxibustion resulted in a marked increase in the survival rate after infection with lethal doses of HSV-1, and elevated serum levels of IL-1β and IFN-γ on days 1 and 6 post-infection with HSV-1. Semi-quantitative RT-PCR assay showed that moxibustion treatment augmented the expression of IL-1α, IL-1β, IL-6, universal-IFN-α, MIP-1α, and TNF-α mRNA in the skin, and IL-1α, IL-1β, IL-12p40, IL-15, u-IFN-α, MIP-1α, and TNF-α mRNA in the spleen. Moreover, moxibustion induces augmentation of natural killer cell activity. Collectively, our study demonstrates that moxibustion activates protective responses against HSV-1 infection through the activation of cytokine production including IFN, and of NK cells.

  10. Effects of temperature on oxidative stress defense systems, lipid peroxidation and lipoxygenase activity in Phalaenopsis.

    PubMed

    Ali, Mohammad Babar; Hahn, Eun-Joo; Paek, Kee-Yoeup

    2005-03-01

    Higher plants growing in natural environments experience various abiotic stresses. The aim of this study was to determine whether exposure to temperature-stress would lead to oxidative stress and whether this effect varied with different exposure periods. The thermal dependencies of the activities of protective enzymes, photosynthetic efficiency (Fv/Fm), protein, non-protein thiol (NP-SH), cysteine content, lipoxygenase (LOX) activity (EC 1.13.11.12) and malondialdehyde (MDA) content at 25-40 degrees C were determined for 4, 24 and 48 h in leaf and root segments of Phalaenopsis. The increase in MDA level and LOX activity may be due to temperature-associated oxidative damage to leaf and root segments. Temperature-stress induced not only activities of active oxygen species (AOS) scavenging enzymes but also protein, NP-SH and cysteine content in both leaf and root segments at 30 degrees C for 4 and 24 h (except for 48 h in some cases) compared to 25 degrees C-and greenhouse-grown leaf and root segments indicating that antioxidants enzymes played an important role in protecting plant from temperature-stress. However, activities of dehydroascorbate reductase (DHAR, EC 1.8.5.1), glutathione peroxidase (GPX, EC 1.11.1.9) and glutathione-S-transferase (GST, EC 2.5.1.18) in leaf and root, glutathione reductase (GR, EC 1.6.4.2) in leaf and guaiacol peroxidase (G-POD, 1.11.1.7) in root segments were induced significantly at 40 degrees C compared to 25 degrees C and greenhouse-grown plants suggesting that these enzymes play protective roles at high temperature. In contrast, activities of superoxide dismutase (SOD, EC 1.15.1.1) and monodehydroascorbate reductase (MDHAR, EC 1.6.5.4) in leaf and root, catalase (CAT, EC 1.11.1.6) in root, GR in root, and protein, cysteine, NP-SH content in both root and leaf and Fv/Fm ratio were diminished significantly at 40 degrees C compared to 25 degrees C-and greenhouse-grown plants. These indicate that these enzymes were apparently not

  11. Bi-functional peptides with both trypsin-inhibitory and antimicrobial activities are frequent defensive molecules in Ranidae amphibian skins.

    PubMed

    Yan, Xiuwen; Liu, Huan; Yang, Xuening; Che, Qiaolin; Liu, Rui; Yang, Hailong; Liu, Xiuhong; You, Dewen; Wang, Aili; Li, Jianxu; Lai, Ren

    2012-07-01

    Amphibian skins act as the first line against noxious aggression by microorganisms, parasites, and predators. Anti-microorganism activity is an important task of amphibian skins. A large amount of gene-encoded antimicrobial peptides (AMPs) has been identified from amphibian skins. Only a few of small protease inhibitors have been found in amphibian skins. From skin secretions of 5 species (Odorrana livida, Hylarana nigrovittata, Limnonectes kuhlii, Odorrana grahami, and Amolops loloensis) of Ranidae frogs, 16 small serine protease inhibitor peptides have been purified and characterized. They have lengths of 17-20 amino acid residues (aa). All of them are encoded by precursors with length of 65-70 aa. These small peptides show strong trypsin-inhibitory abilities. Some of them can exert antimicrobial activities. They share the conserved GCWTKSXXPKPC fragment in their primary structures, suggesting they belong to the same families of peptide. Signal peptides of precursors encoding these serine protease inhibitors share obvious sequence similarity with those of precursors encoding AMPs from Ranidae frogs. The current results suggest that these small serine protease inhibitors are the common defensive compounds in frog skin of Ranidae as amphibian skin AMPs.

  12. Department of Defense In-House RDT and E Activities Report for Fiscal Year 1990

    DTIC Science & Technology

    1990-01-01

    38 Missile Research, Development & Engineering Center ................................. 39 Natick Research, Development & Emgineering ...with industry and non.profit groups and administration of Naval Research Advisory Committec. 2 AIR FORCE OFFICE OF SCIENTIFIC RESEARCH WASHINGTON, DC...laboratories, industry , and universities complementing the national research effort. CURRENT IMPORTANT PROGRAMS Active vortex control to enhance

  13. Onset of herbivore-induced resistance in systemic tissue primed for jasmonate-dependent defenses is activated by abscisic acid.

    PubMed

    Vos, Irene A; Verhage, Adriaan; Schuurink, Robert C; Watt, Lewis G; Pieterse, Corné M J; Van Wees, Saskia C M

    2013-01-01

    In Arabidopsis, the MYC2 transcription factor on the one hand and the AP2/ERF transcription factors ORA59 and ERF1 on the other hand regulate distinct branches of the jasmonic acid (JA) signaling pathway in an antagonistic fashion, co-regulated by abscisic acid (ABA) and ethylene, respectively. Feeding by larvae of the specialist herbivorous insect Pieris rapae (small cabbage white butterfly) results in activation of the MYC-branch and concomitant suppression of the ERF-branch in insect-damaged leaves. Here we investigated differential JA signaling activation in undamaged systemic leaves of P. rapae-infested plants. We found that the MYC2 transcription factor gene was induced both in the local insect-damaged leaves and the systemic undamaged leaves of P. rapae-infested Arabidopsis plants. However, in contrast to the insect-damaged leaves, the undamaged tissue did not show activation of the MYC-branch marker gene VSP1. Comparison of the hormone signal signature revealed that the levels of JA and (+)-7-iso-jasmonoyl-L-isoleucine raised to similar extents in locally damaged and systemically undamaged leaves, but the production of ABA and the JA precursor 12-oxo-phytodienoic acid was enhanced only in the local herbivore-damaged leaves, and not in the distal undamaged leaves. Challenge of undamaged leaves of pre-infested plants with either P. rapae larvae or exogenously applied ABA led to potentiated expression levels of MYC2 and VSP1, with the latter reaching extremely high expression levels. Moreover, P. rapae-induced resistance, as measured by reduction of caterpillar growth on pre-infested plants, was blocked in the ABA biosynthesis mutant aba2-1, that was also impaired in P. rapae-induced expression of VSP1. Together, these results suggest that ABA is a crucial regulator of herbivore-induced resistance by activating primed JA-regulated defense responses upon secondary herbivore attack in Arabidopsis.

  14. ShadowNet: An Active Defense Infrastructure for Insider Cyber Attack Prevention

    SciTech Connect

    Cui, Xiaohui; Beaver, Justin M; Treadwell, Jim N

    2012-01-01

    The ShadowNet infrastructure for insider cyber attack prevention is comprised of a tiered server system that is able to dynamically redirect dangerous/suspicious network traffic away from production servers that provide web, ftp, database and other vital services to cloned virtual machines in a quarantined environment. This is done transparently from the point of view of both the attacker and normal users. Existing connections, such as SSH sessions, are not interrupted. Any malicious activity performed by the attacker on a quarantined server is not reflected on the production server. The attacker is provided services from the quarantined server, which creates the impression that the attacks performed are successful. The activities of the attacker on the quarantined system are able to be recorded much like a honeypot system for forensic analysis.

  15. Activation of Nrf2 in defense against cadmium-induced oxidative stress.

    PubMed

    He, Xiaoqing; Chen, Michael G; Ma, Qiang

    2008-07-01

    Exposure to cadmium (Cd) elicits a range of adverse responses including oxidative damage and cancer. The molecular targets of Cd remain largely unidentified. Here, we analyzed the function and signal transduction of transcription factor Nrf2 in protection against Cd-induced oxidative stress. Wild-type (Nrf2 (+/+)) mouse embryonic fibroblasts (MEF) produced reactive oxygen species (ROS) at a low level, whereas treatment with Cd significantly increased the ROS production. On the other hand, Nrf2 knockout (Nrf2 (-/-)) MEF cells exhibited an elevated level of ROS under a basal condition, and Cd dramatically increased the ROS production at concentrations as low as 2 microM, resulting in increased sensitivity to Cd-induced cell death. Cd induced the basal and inducible expression of cytoprotective enzymes NQO1 and HO1 in WT MEF cells, but induction was lost in Nrf2 (-/-) MEF cells. Induction of the genes required antioxidant response elements (ARE) as Cd drove ARE-dependent reporter expression and Cd-activated Nrf2 bound to endogenous AREs in mouse hepa1c1c7 cells. Activation of Nrf2 by Cd involved stabilization of the Nrf2 protein, increased formation of Nrf2/Keap1 complex in the cytoplasm, translocation of the complex into the nucleus, and subsequently disruption of the complex. Lastly, Nrf2 was found ubiquitinated in the cytoplasm but deubiquitinated in the nucleus. The study provided a mechanistic transcriptional model in which Cd activates Nrf2 through a metal-activated signaling pathway involving a dynamic interplay between ubiquitination/deubiquitination and complex formation/dissociation of Nrf2 and Keap1.

  16. Department of Defense In-House RDT&E Activities, FY97, Management Analysis Report

    DTIC Science & Technology

    2007-11-02

    IN-HOUSE RDT&E ACTIVITIES REPORT FY97 Navy CURRENT IMPORTANT PROGRAMS (continued) Title: Laser-Heated Thermoluminescent Glass CRADA between NRL and... thermoluminescent glass by modifying the composition of the material by changing concentrations of ions and semiconductor nanocrystalites. It is...anticipated that this will lead to a significant cost reduction for the laser-heated thermoluminescence reader. Title: Laser Oligonucleotide Array Fabrication

  17. Cannabidiol Post-Treatment Alleviates Rat Epileptic-Related Behaviors and Activates Hippocampal Cell Autophagy Pathway Along with Antioxidant Defense in Chronic Phase of Pilocarpine-Induced Seizure.

    PubMed

    Hosseinzadeh, Mahshid; Nikseresht, Sara; Khodagholi, Fariba; Naderi, Nima; Maghsoudi, Nader

    2016-04-01

    Abnormal and sometimes severe behavioral and molecular symptoms are usually observed in epileptic humans and animals. To address this issue, we examined the behavioral and molecular aspects of seizure evoked by pilocarpine. Autophagy can promote both cell survival and death, but there are controversial reports about the neuroprotective or neurodegenerative effects of autophagy in seizure. Cannabidiol has anticonvulsant properties in some animal models when used as a pretreatment. In this study, we investigated alteration of seizure scores, autophagy pathway proteins, and antioxidant status in hippocampal cells during the chronic phase of pilocarpine-induced epilepsy after treatment with cannabidiol. Cannabidiol (100 ng, intracerebroventricular injection) delayed the chronic phase of epilepsy. Single administration of cannabidiol during the chronic phase of seizure significantly diminished seizure scores such as mouth clonus, head nodding, monolateral and bilateral forelimb clonus and increased the activity of catalase enzyme and reduced glutathione content. Such a protective effect in the behavioral scores of epileptic rats was also observed after repeated administrations of cannabidiol at the onset of the silent phase. Moreover, the amount of Atg7, conjugation of Atg5/12, Atg12, and LC3II/LC3I ratio increased significantly in epileptic rats treated with repeated injections of cannabidiol. In short, our results suggest that post-treatment of Cannabidiol could enhance the induction of autophagy pathway and antioxidant defense in the chronic phase of epilepsy, which could be considered as the protective mechanisms of cannabidiol in a temporal lobe epilepsy model.

  18. Nuclear Heme Oxygenase-1 (HO-1) Modulates Subcellular Distribution and Activation of Nrf2, Impacting Metabolic and Anti-oxidant Defenses*

    PubMed Central

    Biswas, Chhanda; Shah, Nidhi; Muthu, Manasa; La, Ping; Fernando, Amal P.; Sengupta, Shaon; Yang, Guang; Dennery, Phyllis A.

    2014-01-01

    With oxidative injury as well as in some solid tumors and myeloid leukemia cells, heme oxygenase-1 (HO-1), the anti-oxidant, anti-inflammatory, and anti-apoptotic microsomal stress protein, migrates to the nucleus in a truncated and enzymatically inactive form. However, the function of HO-1 in the nucleus is not completely clear. Nuclear factor erythroid 2-related factor 2 (Nrf2), a transcription factor and master regulator of numerous antioxidants and anti-apoptotic proteins, including HO-1, also accumulates in the nucleus with oxidative injury and in various types of cancer. Here we demonstrate that in oxidative stress, nuclear HO-1 interacts with Nrf2 and stabilizes it from glycogen synthase kinase 3β (GSK3β)-mediated phosphorylation coupled with ubiquitin-proteasomal degradation, thereby prolonging its accumulation in the nucleus. This regulation of Nrf2 post-induction by nuclear HO-1 is important for the preferential transcription of phase II detoxification enzymes such as NQO1 as well as glucose-6-phosphate dehydrogenase (G6PDH), a regulator of the pentose phosphate pathway. Using Nrf2 knock-out cells, we further demonstrate that nuclear HO-1-associated cytoprotection against oxidative stress depends on an HO-1/Nrf2 interaction. Although it is well known that Nrf2 induces HO-1 leading to mitigation of oxidant stress, we propose a novel mechanism by which HO-1, by modulating the activation of Nrf2, sets an adaptive reprogramming that enhances antioxidant defenses. PMID:25107906

  19. IFN-induced Guanylate Binding Proteins in Inflammasome Activation and Host Defense

    PubMed Central

    Kim, Bae-Hoon; Chee, Jonathan D.; Bradfield, Clinton J.; Park, Eui-Soon; Kumar, Pradeep; MacMicking, John D.

    2016-01-01

    Traditional views of the inflammasome highlight pre-existing core components being assembled under basal conditions shortly after infection or tissue damage. Recent work, however, suggests the inflammasome machinery is also subject to tunable or inducible signals that may accelerate its autocatalytic properties and dictate where inflammasome assembly takes place in the cell. Many of these immune signals operate downstream of interferon (IFN) receptors to elicit inflammasome regulators, including a new family of IFN-induced GTPases termed guanylate binding proteins (GBPs). Here, we examine the critical roles for IFN-induced GBPs in directing inflammasome subtype-specific responses and their consequences for cell-autonomous immunity against a wide variety of microbial pathogens. We discuss emerging mechanisms of action and the potential impact of these GBPs on predisposition to sepsis and other infectious or inflammatory diseases. PMID:27092805

  20. Interferon-induced guanylate-binding proteins in inflammasome activation and host defense.

    PubMed

    Kim, Bae-Hoon; Chee, Jonathan D; Bradfield, Clinton J; Park, Eui-Soon; Kumar, Pradeep; MacMicking, John D

    2016-05-01

    Traditional views of the inflammasome highlight the assembly of pre-existing core components shortly after infection or tissue damage. Emerging work, however, suggests that the inflammasome machinery is also subject to 'tunable' or inducible signals that might accelerate its autocatalytic properties and dictate where inflammasome assembly takes place in the cell. Many of these signals operate downstream of interferon receptors to elicit inflammasome regulators, including a new family of interferon-induced GTPases called 'guanylate-binding proteins' (GBPs). Here we investigate the critical roles of interferon-induced GBPs in directing inflammasome subtype-specific responses and their consequences for cell-autonomous immunity to a wide variety of microbial pathogens. We discuss emerging mechanisms of action and the potential effect of these GBPs on predisposition to sepsis and other infectious or inflammatory diseases.

  1. Physiologic mechanism of the ultrasonically activated scalpel.

    PubMed

    McCarus, S D

    1996-08-01

    An ultrasonically activated scalpel was developed and used clinically to provide hemostatic cutting in laparoscopic surgery. Results of experimental work with the ultrasonic scalpel blades were compared with those of electrosurgery and lasers. Some features that distinguish this energy form may confer specific advantages in various surgical procedures.

  2. The novel mechanism of lenalidomide activity.

    PubMed

    Fink, Emma C; Ebert, Benjamin L

    2015-11-19

    Lenalidomide acts by a novel drug mechanism-modulation of the substrate specificity of the CRL4(CRBN) E3 ubiquitin ligase. In multiple myeloma, lenalidomide induces the ubiquitination of IKZF1 and IKZF3 by CRL4(CRBN). Subsequent proteasomal degradation of these transcription factors kills multiple myeloma cells. In del(5q) myelodysplastic syndrome, lenalidomide induces the degradation of CK1α, which preferentially affects del(5q) cells because they express this gene at haploinsufficient levels. In the future, modulation of ubiquitin ligase function may enable us to target previously "undruggable" proteins.

  3. Optimal Control of Active Recoil Mechanisms

    DTIC Science & Technology

    1977-02-01

    forces from 25 to 2.5% for lower zones and cavitation was avoided for zone 8. Tachometer feedback was shown to be effective for low zones. The...concept of feedback control system coupled with optimization procedure to design recoil mechanisms was demonstrated to be an efficient and very effective ...122o •nl260 .01300 .01340 .01380 • ouzo #01460 •01500 •01540 •01580 •0162" .0166 i 309o,6 504P.6 9964.5 10075,9 39121.5 75397.3

  4. [The evolutionary role of nitric oxide in circadian activity and defense of the organism from cosmic rays].

    PubMed

    Iamshanov, V A

    2009-01-01

    The cosmic rays are one of the constantly acting factors influencing on genetic apparatus and depending from sun activity, which have the circadian rhythm. The nature creates a number of mechanisms, which defend the organism from cosmic rays and free radicals as consequence. However, the malfunctions of these mechanisms damage the genetic apparatus, accelerate the aging and bring to a number of illnesses. It is supposed that to neutralise the free radicals as cosmic rays consequence the organism uses its own free radicals, which have the physiological functions, for example, the nitric oxide. To limit the nitric oxide production, the mechanism of melatonin formation is used, which has a circadian rhythm.

  5. AMPK activators: mechanisms of action and physiological activities

    PubMed Central

    Kim, Joungmok; Yang, Goowon; Kim, Yeji; Kim, Jin; Ha, Joohun

    2016-01-01

    AMP-activated protein kinase (AMPK) is a central regulator of energy homeostasis, which coordinates metabolic pathways and thus balances nutrient supply with energy demand. Because of the favorable physiological outcomes of AMPK activation on metabolism, AMPK has been considered to be an important therapeutic target for controlling human diseases including metabolic syndrome and cancer. Thus, activators of AMPK may have potential as novel therapeutics for these diseases. In this review, we provide a comprehensive summary of both indirect and direct AMPK activators and their modes of action in relation to the structure of AMPK. We discuss the functional differences among isoform-specific AMPK complexes and their significance regarding the development of novel AMPK activators and the potential for combining different AMPK activators in the treatment of human disease. PMID:27034026

  6. Ornithine and Homocitrulline Impair Mitochondrial Function, Decrease Antioxidant Defenses and Induce Cell Death in Menadione-Stressed Rat Cortical Astrocytes: Potential Mechanisms of Neurological Dysfunction in HHH Syndrome.

    PubMed

    Zanatta, Ângela; Rodrigues, Marília Danyelle Nunes; Amaral, Alexandre Umpierrez; Souza, Débora Guerini; Quincozes-Santos, André; Wajner, Moacir

    2016-09-01

    Hyperornithinemia-hyperammonemia-homocitrullinuria (HHH) syndrome is caused by deficiency of ornithine translocase leading to predominant tissue accumulation and high urinary excretion of ornithine (Orn), homocitrulline (Hcit) and ammonia. Although affected patients commonly present neurological dysfunction manifested by cognitive deficit, spastic paraplegia, pyramidal and extrapyramidal signs, stroke-like episodes, hypotonia and ataxia, its pathogenesis is still poorly known. Although astrocytes are necessary for neuronal protection. Therefore, in the present study we investigated the effects of Orn and Hcit on cell viability (propidium iodide incorporation), mitochondrial function (thiazolyl blue tetrazolium bromide-MTT-reduction and mitochondrial membrane potential-ΔΨm), antioxidant defenses (GSH) and pro-inflammatory response (NFkB, IL-1β, IL-6 and TNF-α) in unstimulated and menadione-stressed cortical astrocytes that were previously shown to be susceptible to damage by neurotoxins. We first observed that Orn decreased MTT reduction, whereas both amino acids decreased GSH levels, without altering cell viability and the pro-inflammatory factors in unstimulated astrocytes. Furthermore, Orn and Hcit decreased cell viability and ΔΨm in menadione-treated astrocytes. The present data indicate that the major compounds accumulating in HHH syndrome impair mitochondrial function and reduce cell viability and the antioxidant defenses in cultured astrocytes especially when stressed by menadione. It is presumed that these mechanisms may be involved in the neuropathology of this disease.

  7. Molecular cloning of the tomato Hairless gene implicates actin dynamics in trichome-mediated defense and mechanical properties of stem tissue

    PubMed Central

    Kang, Jin-Ho; Campos, Marcelo L.; Zemelis-Durfee, Starla; Al-Haddad, Jameel M.; Jones, A. Daniel; Telewski, Frank W.; Brandizzi, Federica; Howe, Gregg A.

    2016-01-01

    Trichomes are epidermal structures that provide a first line of defense against arthropod herbivores. The recessive hairless (hl) mutation in tomato (Solanum lycopersicum L.) causes severe distortion of trichomes on all aerial tissues, impairs the accumulation of sesquiterpene and polyphenolic compounds in glandular trichomes, and compromises resistance to the specialist herbivore Manduca sexta. Here, we demonstrate that the tomato Hl gene encodes a subunit (SRA1) of the highly conserved WAVE regulatory complex that controls nucleation of actin filaments in a wide range of eukaryotic cells. The tomato SRA1 gene spans a 42-kb region containing both Solyc11g013280 and Solyc11g013290. The hl mutation corresponds to a complex 3-kb deletion that removes the last exon of the gene. Expression of a wild-type SRA1 cDNA in the hl mutant background restored normal trichome development, accumulation of glandular trichome-derived metabolites, and resistance to insect herbivory. These findings establish a role for SRA1 in the development of tomato trichomes and also implicate the actin-cytoskeleton network in cytosolic control of specialized metabolism for plant defense. We also show that the brittleness of hl mutant stems is associated with altered mechanical and cell morphological properties of stem tissue, and demonstrate that this defect is directly linked to the mutation in SRA1. PMID:27481446

  8. Molecular cloning of the tomato Hairless gene implicates actin dynamics in trichome-mediated defense and mechanical properties of stem tissue.

    PubMed

    Kang, Jin-Ho; Campos, Marcelo L; Zemelis-Durfee, Starla; Al-Haddad, Jameel M; Jones, A Daniel; Telewski, Frank W; Brandizzi, Federica; Howe, Gregg A

    2016-10-01

    Trichomes are epidermal structures that provide a first line of defense against arthropod herbivores. The recessive hairless (hl) mutation in tomato (Solanum lycopersicum L.) causes severe distortion of trichomes on all aerial tissues, impairs the accumulation of sesquiterpene and polyphenolic compounds in glandular trichomes, and compromises resistance to the specialist herbivore Manduca sexta Here, we demonstrate that the tomato Hl gene encodes a subunit (SRA1) of the highly conserved WAVE regulatory complex that controls nucleation of actin filaments in a wide range of eukaryotic cells. The tomato SRA1 gene spans a 42-kb region containing both Solyc11g013280 and Solyc11g013290 The hl mutation corresponds to a complex 3-kb deletion that removes the last exon of the gene. Expression of a wild-type SRA1 cDNA in the hl mutant background restored normal trichome development, accumulation of glandular trichome-derived metabolites, and resistance to insect herbivory. These findings establish a role for SRA1 in the development of tomato trichomes and also implicate the actin-cytoskeleton network in cytosolic control of specialized metabolism for plant defense. We also show that the brittleness of hl mutant stems is associated with altered mechanical and cell morphological properties of stem tissue, and demonstrate that this defect is directly linked to the mutation in SRA1.

  9. Lipid Dependent Mechanisms of Protein Pump Activity

    DTIC Science & Technology

    1989-05-23

    properties which result form the colligative interactions of many lipid molecules. Important materials properties include . . . i I I II II I i I 1 the...d identify by olock number) *This project is aime at investigating if a lipid elastic property , known as the spontaneous radius of curvature Ro’, is...a regulated membrane property and if its value modulates membrane protein activity. Specific aims reported on here include: 1) Correlation of ion pump

  10. Tomato Transcription Factors Pti4, Pti5, and Pti6 Activate Defense Responses When Expressed in Arabidopsis

    PubMed Central

    Gu, Yong-Qiang; Wildermuth, Mary C.; Chakravarthy, Suma; Loh, Ying-Tsu; Yang, Caimei; He, Xiaohua; Han, Yu; Martin, Gregory B.

    2002-01-01

    The Pti4, Pti5, and Pti6 proteins from tomato were identified based on their interaction with the product of the Pto disease resistance gene, a Ser-Thr protein kinase. They belong to the ethylene-response factor (ERF) family of plant-unique transcription factors and bind specifically to the GCC-box cis element present in the promoters of many pathogenesis-related (PR) genes. Here, we show that these tomato ERFs are localized to the nucleus and function in vivo as transcription activators that regulate the expression of GCC box–containing PR genes. Expression of Pti4, Pti5, or Pti6 in Arabidopsis activated the expression of the salicylic acid–regulated genes PR1 and PR2. Expression of jasmonic acid– and ethylene-regulated genes, such as PR3, PR4, PDF1.2, and Thi2.1, was affected differently by each of the three tomato ERFs, with Arabidopsis-Pti4 plants having very high levels of PDF1.2 transcripts. Exogenous application of salicylic acid to Arabidopsis-Pti4 plants suppressed the increased expression of PDF1.2 but further stimulated PR1 expression. Arabidopsis plants expressing Pti4 displayed increased resistance to the fungal pathogen Erysiphe orontii and increased tolerance to the bacterial pathogen Pseudomonas syringae pv tomato. These results indicate that Pti4, Pti5, and Pti6 activate the expression of a wide array of PR genes and play important and distinct roles in plant defense. PMID:11971137

  11. Structure-activity relationships of pyrrolizidine alkaloids in insect chemical defense against the orb-weaving spider Nephila clavipes.

    PubMed

    Silva, Karina Lucas; Trigo, José Roberto

    2002-04-01

    Pyrrolizidine alkaloids (PAs) are known to protect Arctiidae moths and Danainae and Ithomiinae butterflies against the orb-weaving spider Nephila clavipes (Araneae, Araneidae, Tetragnathinae), which liberates adults of these insects unharmed from its web. We tested against this spider the role of eight PAs and one derived structure [an 89:11 mixture of the 12-membered macrocyclic diester free base integerrimine and senecionine and the respective N-oxide; two hydrolysis products from this mixture (the necine base retronecine, its respective N-oxide, and a mixture of integerriminic and senecionic necic acids); the 12-membered macrocyclic senkirkine; the 9-O-monoester free base senecioylretronecine and its respective N-oxide; and the 9-O-monoester free base callimorphine (a PA biosynthesized only by insects from retronecine)]. The mixture integerrimine-senecionine N-oxide seems to be more active than the respective free base [LibD50 (liberation dose 50) = 0.042 and 0.153 microg/dry weight of prey, respectively], but the difference in activity between the N-oxide and free base of the 9-O-monoester senecioylretronecine was slight (LibD50 = 0.167 and 0.104, respectively). Senkirkine, an otonecine base PA that does not form N-oxide and is not found in insects, was the less active, showing the highest LibD50 (0.354). The difference in antipredator activity between N-oxides and free bases from macrocyclic diesters and monoesters may be correlated with physicochemical properties of these molecules in interaction with the Nephila receptors. For the active structures, there was a significant correlation between dosage and antipredator activity. Both forms of retronecine and a necic acid mixture were inactive, supporting the hypothesis that PAs biosynthesized by insects from retronecine were originally produced and stored in order to optimize chemical defense. Comparison of dose/activity data with reported amounts of PAs in butterflies suggested that, in general, PA

  12. Defense of zebrafish embryos against Streptococcus pneumoniae infection is dependent on the phagocytic activity of leukocytes.

    PubMed

    Rounioja, Samuli; Saralahti, Anni; Rantala, Lilli; Parikka, Mataleena; Henriques-Normark, Birgitta; Silvennoinen, Olli; Rämet, Mika

    2012-02-01

    Severe community acquired pneumonia caused by Streptococcus pneumoniae is the most common cause of death from infection in developing countries. Serotype specific conjugate vaccines have decreased the incidence of invasive infections, but at the same time, disease due to non-vaccine serotypes have increased. New insights into host immune mechanisms against pneumococcus may provide better treatment and prevention strategies. Zebrafish is an attractive vertebrate model for studying host immune responses and infection biology. Here we show that an intravenous challenge with pneumococcus infects zebrafish embryos leading to death in a dose dependent manner. Survival rates correlate with the bacterial burden in the embryos. The production of proinflammatory cytokines is induced in zebrafish after pneumococcal exposure. Importantly, morpholino treated embryos lacking either myeloid cells or the ability to phagocytose bacteria have lowered survival rates compared to wild type embryos after pneumococcal challenge. These data suggest that the survival of zebrafish embryos upon intravenous infection with S. pneumoniae is dependent on the clearance of the bacteria by phagocytosing cells. Additionally, we demonstrate that mutant pneumococci lacking known virulence factors are attenuated in the zebrafish model. Our data demonstrate that zebrafish embryos can be used for study innate immune responses as well as virulence determinants in pneumococcal infections.

  13. Functional Analysis of Plant Defense Suppression and Activation by the Xanthomonas Core Type III Effector XopX.

    PubMed

    Stork, William; Kim, Jung-Gun; Mudgett, Mary Beth

    2015-02-01

    Many phytopathogenic type III secretion effector proteins (T3Es) have been shown to target and suppress plant immune signaling but perturbation of the plant immune system by T3Es can also elicit a plant response. XopX is a "core" Xanthomonas T3E that contributes to growth and symptom development during Xanthomonas euvesicatoria infection of tomato but its functional role is undefined. We tested the effect of XopX on several aspects of plant immune signaling. XopX promoted ethylene production and plant cell death (PCD) during X. euvesicatoria infection of susceptible tomato and in transient expression assays in Nicotiana benthamiana, which is consistent with its requirement for the development of X. euvesicatoria-induced disease symptoms. Additionally, although XopX suppressed flagellin-induced reactive oxygen species, it promoted the accumulation of pattern-triggered immunity (PTI) gene transcripts. Surprisingly, XopX coexpression with other PCD elicitors resulted in delayed PCD, suggesting antagonism between XopX-dependent PCD and other PCD pathways. However, we found no evidence that XopX contributed to the suppression of effector-triggered immunity during X. euvesicatoria-tomato interactions, suggesting that XopX's primary virulence role is to modulate PTI. These results highlight the dual role of a core Xanthomonas T3E in simultaneously suppressing and activating plant defense responses.

  14. Acclimation of hydrogen peroxide enhances salt tolerance by activating defense-related proteins in Panax ginseng C.A. Meyer.

    PubMed

    Sathiyaraj, Gayathri; Srinivasan, Sathiyaraj; Kim, Yu-Jin; Lee, Ok Ran; Parvin, Shonana; Balusamy, Sri Renuka Devi; Khorolragchaa, Atlanzul; Yang, Deok Chun

    2014-06-01

    The effect of exogenously applied hydrogen peroxide on salt stress tolerance was investigated in Panax ginseng. Pretreatment of ginseng seedlings with 100 μM H2O2 increased the physiological salt tolerance of the ginseng plant and was used as the optimum concentration to induce salt tolerance capacity. Treatment with exogenous H2O2 for 2 days significantly enhanced salt stress tolerance in ginseng seedlings by increasing the activities of ascorbate peroxidase, catalase and guaiacol peroxidase and by decreasing the concentrations of malondialdehyde (MDA) and endogenous H2O2 as well as the production rate of superoxide radical (O2(-)). There was a positive physiological effect on the growth and development of salt-stressed seedlings by exogenous H2O2 as measured by ginseng dry weight and both chlorophyll and carotenoid contents. Exogenous H2O2 induced changes in MDA, O2(-), antioxidant enzymes and antioxidant compounds, which are responsible for increases in salt stress tolerance. Salt treatment caused drastic declines in ginseng growth and antioxidants levels; whereas, acclimation treatment with H2O2 allowed the ginseng seedlings to recover from salt stress by up-regulation of defense-related proteins such as antioxidant enzymes and antioxidant compounds.

  15. Mechanism for Clastogenic Activity of Naphthalene

    SciTech Connect

    Buchholz, Bruce A.

    2015-09-29

    Naphthalene incubations form DNA adducts in vitro in a dose dependent manner in both mouse and rat tissues. Rodent tissue incubations with naphthalene indicate that naphthalene forms as many DNA adducts as Benzo(a)pyrene, a known DNA binding carcinogen. The mouse airway has the greatest number of DNA adducts, corresponding to the higher metabolic activation of naphthalene in this location. Both rat tissues, the rat olfactory (tumor target) and the airways (non-tumor target), have similar levels of NA-DNA adducts, indicating that short term measures of initial adduct formation do not directly correlate with sites of tumor formation in the NTP bioassays.

  16. Mechanism for Clastogenic Activity of Naphthalene

    SciTech Connect

    Buchholz, Bruce A.

    2016-06-24

    Naphthalene incubations form DNA adducts in vitro in a dose dependent manner in both mouse and rat tissues. Rodent tissue incubations with naphthalene indicate that naphthalene forms as many DNA adducts as Benzo(a)pyrene, a known DNA binding carcinogen. The mouse airway has the greatest number of DNA adducts, corresponding to the higher metabolic activation of naphthalene in this location. Both rat tissues, the rat olfactory (tumor target) and the airways (non-tumor target), have similar levels of NA-DNA adducts, indicating that short term measures of initial adduct formation do not directly correlate with sites of tumor formation in the NTP bioassays.

  17. Neutrophil activation: an alternative to prostaglandin inhibition as the mechanism of action for NSAIDs.

    PubMed

    Altman, R D

    1990-02-01

    Experimental findings suggest that inhibition of neutrophil activation rather than suppression of prostaglandin formation may represent the principal mechanism of action of antiinflammatory drugs. This theory would account for the effectiveness of prostaglandin preserving agents, such as the nonacetylated salicylate salsalate, in the treatment of rheumatic disease. Results of the controlled clinical trials described in other papers contained in this supplement indicate that salsalate is equally effective as aspirin and the newer NSAID naproxen in relieving the signs and symptoms of rheumatoid arthritis. The damage to the gastric mucosa associated with NSAID use is believed to be attributable to impairment of mucosal defense mechanisms resulting from the inhibition of gastroprotective prostaglandins. Confirmation of neutrophil activation as the mechanism of action of NSAIDs would explain the efficacy of salsalate in light of its lower incidence of gastrointestinal side effects in controlled clinical trials with aspirin and naproxen. Establishment of such a mechanism would also suggest that the other adverse effects related to prostaglandin inhibition, such as hypersensitivity reactions, platelet dysfunction, and a reduction in renal function, are not necessary correlates of effective antiinflammatory therapy.

  18. Co-occurring increases of calcium and organellar reactive oxygen species determine differential activation of antioxidant and defense enzymes in Ulva compressa (Chlorophyta) exposed to copper excess.

    PubMed

    Gonzalez, Alberto; Vera, Jeannette; Castro, Jorge; Dennett, Geraldine; Mellado, Macarena; Morales, Bernardo; Correa, Juan A; Moenne, Alejandra

    2010-10-01

    In order to analyse copper-induced calcium release and (reactive oxygen species) ROS accumulation and their role in antioxidant and defense enzymes activation, the marine alga Ulva compressa was exposed to 10 µM copper for 7 d. The level of calcium, extracellular hydrogen peroxide (eHP), intracellular hydrogen peroxide (iHP) and superoxide anions (SA) as well as the activities of ascorbate peroxidase (AP), glutathione reductase (GR), glutathione-S-transferase (GST), phenylalanine ammonia lyase (PAL) and lipoxygenase (LOX) were determined. Calcium release showed a triphasic pattern with peaks at 2, 3 and 12 h. The second peak was coincident with increases in eHP and iHP and the third peak with the second increase of iHP. A delayed wave of SA occurred after day 3 and was not accompanied by calcium release. The accumulation of iHP and SA was mainly inhibited by organellar electron transport chains inhibitors (OETCI), whereas calcium release was inhibited by ryanodine. AP activation ceased almost completely after the use of OETCI. On the other hand, GR and GST activities were partially inhibited, whereas defense enzymes were not inhibited. In contrast, PAL and LOX were inhibited by ryanodine, whereas AP was not inhibited. Thus, copper stress induces calcium release and organellar ROS accumulation that determine the differential activation of antioxidant and defense enzymes.

  19. Mechanism of antibacterial activity of copper nanoparticles

    NASA Astrophysics Data System (ADS)

    Chatterjee, Arijit Kumar; Chakraborty, Ruchira; Basu, Tarakdas

    2014-04-01

    In a previous communication, we reported a new method of synthesis of stable metallic copper nanoparticles (Cu-NPs), which had high potency for bacterial cell filamentation and cell killing. The present study deals with the mechanism of filament formation and antibacterial roles of Cu-NPs in E. coli cells. Our results demonstrate that NP-mediated dissipation of cell membrane potential was the probable reason for the formation of cell filaments. On the other hand, Cu-NPs were found to cause multiple toxic effects such as generation of reactive oxygen species, lipid peroxidation, protein oxidation and DNA degradation in E. coli cells. In vitro interaction between plasmid pUC19 DNA and Cu-NPs showed that the degradation of DNA was highly inhibited in the presence of the divalent metal ion chelator EDTA, which indicated a positive role of Cu2+ ions in the degradation process. Moreover, the fast destabilization, i.e. the reduction in size, of NPs in the presence of EDTA led us to propose that the nascent Cu ions liberated from the NP surface were responsible for higher reactivity of the Cu-NPs than the equivalent amount of its precursor CuCl2; the nascent ions were generated from the oxidation of metallic NPs when they were in the vicinity of agents, namely cells, biomolecules or medium components, to be reduced simultaneously.

  20. Mechanism of antibacterial activity of copper nanoparticles.

    PubMed

    Chatterjee, Arijit Kumar; Chakraborty, Ruchira; Basu, Tarakdas

    2014-04-04

    In a previous communication, we reported a new method of synthesis of stable metallic copper nanoparticles (Cu-NPs), which had high potency for bacterial cell filamentation and cell killing. The present study deals with the mechanism of filament formation and antibacterial roles of Cu-NPs in E. coli cells. Our results demonstrate that NP-mediated dissipation of cell membrane potential was the probable reason for the formation of cell filaments. On the other hand, Cu-NPs were found to cause multiple toxic effects such as generation of reactive oxygen species, lipid peroxidation, protein oxidation and DNA degradation in E. coli cells. In vitro interaction between plasmid pUC19 DNA and Cu-NPs showed that the degradation of DNA was highly inhibited in the presence of the divalent metal ion chelator EDTA, which indicated a positive role of Cu(2+) ions in the degradation process. Moreover, the fast destabilization, i.e. the reduction in size, of NPs in the presence of EDTA led us to propose that the nascent Cu ions liberated from the NP surface were responsible for higher reactivity of the Cu-NPs than the equivalent amount of its precursor CuCl2; the nascent ions were generated from the oxidation of metallic NPs when they were in the vicinity of agents, namely cells, biomolecules or medium components, to be reduced simultaneously.

  1. Disentangling Detoxification: Gene Expression Analysis of Feeding Mountain Pine Beetle Illuminates Molecular-Level Host Chemical Defense Detoxification Mechanisms

    PubMed Central

    Robert, Jeanne A.; Pitt, Caitlin; Bonnett, Tiffany R.; Yuen, Macaire M. S.; Keeling, Christopher I.; Bohlmann, Jörg; Huber, Dezene P. W.

    2013-01-01

    The mountain pine beetle, Dendroctonus ponderosae, is a native species of bark beetle (Coleoptera: Curculionidae) that caused unprecedented damage to the pine forests of British Columbia and other parts of western North America and is currently expanding its range into the boreal forests of central and eastern Canada and the USA. We conducted a large-scale gene expression analysis (RNA-seq) of mountain pine beetle male and female adults either starved or fed in male-female pairs for 24 hours on lodgepole pine host tree tissues. Our aim was to uncover transcripts involved in coniferophagous mountain pine beetle detoxification systems during early host colonization. Transcripts of members from several gene families significantly increased in insects fed on host tissue including: cytochromes P450, glucosyl transferases and glutathione S-transferases, esterases, and one ABC transporter. Other significantly increasing transcripts with potential roles in detoxification of host defenses included alcohol dehydrogenases and a group of unexpected transcripts whose products may play an, as yet, undiscovered role in host colonization by mountain pine beetle. PMID:24223726

  2. Current understanding of grapevine defense mechanisms against the biotrophic fungus (Erysiphe necator), the causal agent of powdery mildew disease

    PubMed Central

    Qiu, Wenping; Feechan, Angela; Dry, Ian

    2015-01-01

    The most economically important disease of cultivated grapevines worldwide is powdery mildew (PM) caused by the ascomycete fungus Erysiphe necator. The majority of grapevine cultivars used for wine, table grape, and dried fruit production are derived from the Eurasian grape species Vitis vinifera because of its superior aroma and flavor characteristics. However, this species has little genetic resistance against E. necator meaning that grape production is highly dependent on the frequent use of fungicides. The integration of effective genetic resistance into cultivated grapevines would lead to significant financial and environmental benefits and represents a major challenge for viticultural industries and researchers worldwide. This review will outline the strategies being used to increase our understanding of the molecular basis of V. vinifera susceptibility to this fungal pathogen. It will summarize our current knowledge of different resistance loci/genes that have evolved in wild grapevine species to restrict PM infection and assess the potential application of these defense genes in the generation of PM-resistant grapevine germplasm. Finally, it addresses future research priorities which will be important in the rapid identification, evaluation, and deployment of new PM resistance genes which are capable of conferring effective and durable resistance in the vineyard. PMID:26504571

  3. Effect of delta-9-tetrahydrocannabinol on altered antioxidative enzyme defense mechanisms and lipid peroxidation in mice testes.

    PubMed

    Mandal, Tapas Kumar; Das, Niladri Sekhar

    2009-04-01

    The present study examined the adverse effects of delta-9-tetrahydrocannabinol (i.p injection in albino mice) on free radical damage of testicular lipids (lipid peroxidation) at low doses and the role of antioxidant enzymes defense system at high dose and particularly at the withdrawal of the drug after applying higher dose (recovery dose). At lower doses (total doses ranging from 6 mg to 28 mg), there was a significant increase of lipid peroxidation and decrease in testicular lipid content. But the effects were slightly lowered at high dose (total dose 70 mg) and at the withdrawal of the drug (recovery dose). Similarly, marked decrease of antioxidant enzyme systems (superoxide dismutase, catalase, and glutathione peroxidase) and glutathione content were noticed at low doses. But the effects were slightly higher at high dose and at the withdrawal of the drug. Similarly, low-dose treatments caused significant shrinkage of tubular diameter and detrimental changes in seminiferous epithelium of testis resulting in lowered plasma testosterone and pituitary gonadotropins (follicular stimulating and luteinizing hormone levels. But at high dose and particularly at withdrawal of the drug, regression of seminiferous tubules and recovery of various germ cell layers of testes through the revival of testosterone hormone and pituitary gonadotropins were observed.

  4. Disentangling detoxification: gene expression analysis of feeding mountain pine beetle illuminates molecular-level host chemical defense detoxification mechanisms.

    PubMed

    Robert, Jeanne A; Pitt, Caitlin; Bonnett, Tiffany R; Yuen, Macaire M S; Keeling, Christopher I; Bohlmann, Jörg; Huber, Dezene P W

    2013-01-01

    The mountain pine beetle, Dendroctonus ponderosae, is a native species of bark beetle (Coleoptera: Curculionidae) that caused unprecedented damage to the pine forests of British Columbia and other parts of western North America and is currently expanding its range into the boreal forests of central and eastern Canada and the USA. We conducted a large-scale gene expression analysis (RNA-seq) of mountain pine beetle male and female adults either starved or fed in male-female pairs for 24 hours on lodgepole pine host tree tissues. Our aim was to uncover transcripts involved in coniferophagous mountain pine beetle detoxification systems during early host colonization. Transcripts of members from several gene families significantly increased in insects fed on host tissue including: cytochromes P450, glucosyl transferases and glutathione S-transferases, esterases, and one ABC transporter. Other significantly increasing transcripts with potential roles in detoxification of host defenses included alcohol dehydrogenases and a group of unexpected transcripts whose products may play an, as yet, undiscovered role in host colonization by mountain pine beetle.

  5. Mechanism of photodynamic activity of pheophorbides.

    PubMed

    Tanielian, C; Kobayashi, M; Wolff, C

    2001-04-01

    Plasmid DNA is efficiently photocleaved by sodium pheophorbides (Na-Phdes) a and b in the absence of oxygen as well as in the presence of oxygen. Fluorescence microscopic observation shows a rapid incorporation of Na-Phde a into nuclei, mitochondria, and lysosome of human oral mucosa cells. In contrast Na-Phde b is incorporated only into the plasma membrane. The photodynamic activity of these pigments in living tissues is probably determined by the monomeric pigment molecules formed in hydrophobic cellular structures and involves two types of reactions: (i) direct electron transfer between DNA bases (especially guanine) and pheophorbide singlet excited state, and (ii) indirect reactions mediated by reactive oxygen species, including singlet oxygen whose production from molecular oxygen is sensitized by the Na-Phdes triplet state. A preliminary report has appeared in "Photodynamic Therapy of Cancer II," Proc. SPIE 2325, 416-424 (1994).

  6. Electro-Mechanical Manipulator for Use in the Remote Equipment Decontamination Cell at the Defense Waste Processing Facility, Savannah River Site - 12454

    SciTech Connect

    Lambrecht, Bill; Dixon, Joe; Neuville, John R.

    2012-07-01

    One of the legacies of the cold war is millions of liters of radioactive waste. One of the locations where this waste is stored is at the Savannah River Site (SRS) in South Carolina. A major effort to clean up this waste is on-going at the defense waste processing facility (DWPF) at SRS. A piece of this effort is decontamination of the equipment used in the DWPF to process the waste. The remote equipment decontamination cell (REDC) in the DWPF uses electro-mechanical manipulators (EMM) arms manufactured and supplied by PaR Systems to decontaminate DWPF process equipment. The decontamination fluid creates a highly corrosive environment. After 25 years of operational use the original EMM arms are aging and need replacement. To support continued operation of the DWPF, two direct replacement EMM arms were delivered to the REDC in the summer of 2011. (authors)

  7. Modulation of Potassium Channel Activity in the Balance of ROS and ATP Production by Durum Wheat Mitochondria—An Amazing Defense Tool Against Hyperosmotic Stress

    PubMed Central

    Trono, Daniela; Laus, Maura N.; Soccio, Mario; Alfarano, Michela; Pastore, Donato

    2015-01-01

    (mannitol or NaCl), PmitoKATP was found to be activated by ROS, so inhibiting further large-scale ROS production according to a feedback mechanism; moreover, a stress-activated phospholipase A2 may generate FFAs, further activating the channel. In conclusion, a main property of PmitoKATP is the ability to keep in balance the control of harmful ROS with the mitochondrial/cellular bioenergetics, thus preserving ATP for energetic needs of cell defense under stress. PMID:26648958

  8. Mesodesma mactroides Gill Cells Exposed to Copper: Does Hyposmotic Saline Increase Cytotoxicity or Cellular Defenses?

    PubMed

    Anjos, V A; Galvão, J S; Santos, V R S; Souza, M M

    2016-11-01

    Gill cells of filter feeding mollusks have cellular defense mechanisms, such as multixenobiotic resistance (MXR), that allow them to extrude possible contaminants. To analyze the cytotoxicity and cellular defenses of gills in the clam Mesodesma mactroides, gill cells were exposed to copper in both iso- and hyposmotic solutions. Analysis of MXR activity by fluorescence microscopy showed that hyposmotic saline activated defenses, whereas the presence of copper in isosmotic solution inhibited the activation of defenses. Cell viability was decreased in cells exposed to copper in isosmotic saline, but not in cells exposed to hyposmotic saline. We conclude that when cells cannot defend themselves due to decreased MXR, cell death occurs. In addition, gill cells under hyposmotic conditions have a greater capacity for defense and a lower rate of cellular mortality than when they are maintained under isosmotic conditions.

  9. Irradiation influence on the phenoloxidase pathway and an anti-oxidant defense mechanism in Spodoptera litura (Lepidoptera: Noctuidae) and its implication in radio-genetic 'F 1 sterility' and biorational pest suppression tactics.

    PubMed

    Sachdev, B; Khan, Z; Zarin, M; Malhotra, P; Seth, R K; Bhatnagar, R K

    2017-01-31

    The present study was conducted to appraise the ontogenic radio-sensitivity of a serious tropical pest, Spodoptera litura (Fabr.). The molecular responses pertaining to the phenoloxidase (PO) pathway and an anti-oxidant defense mechanism were evaluated in order to understand its implication in pest control at pre-harvest and post-harvest intervals. Irradiation exhibited an inverse relationship with age with respect to impact on developmental and transcriptional responses. Transcript abundance of PO cascade enzymes, prophenoloxidase (slppo-2), its activating enzyme (slppae-1) and free-radical scavenging enzymes, superoxide dismutase (slsod) and catalase (slcat) was evaluated upon gamma irradiation alone and the dual-stress of radiation plus microbial challenge. The slppo-2, slppae-1, slsod and slcat transcripts were significantly up-regulated in F 1 L6 larvae (6th-instar) resulting from 100 Gy sub-sterilized male adults and unirradiated female moths. The extent of upregulation was relatively higher in comparison with L6 survivors (6th-instar larvae) developed from irradiated neonates (L1) treated with 100 Gy. Upon Photorhabdus challenge, the transcripts were down-regulated in irradiated L1 suggesting increased larval susceptibility to bacterial infections. Radioresistance increased with the age of the insect, and molecular responses (transcript abundance) of insect defense mechanism were less influenced when older age (F 1 progeny) were irradiated. These findings will help to optimize the gamma dose to be employed in inherited sterility technique for (pre-harvest) pest suppression and (post-harvest) phytosanitation and quarantine, and suggest compatible integration of biorational tactics including nuclear technology.

  10. EROD activity and antioxidant defenses of sea bass (Dicentrarchus labrax) after an in vivo chronic hydrocarbon pollution followed by a post-exposure period.

    PubMed

    Danion, Morgane; Le Floch, Stéphane; Lamour, François; Quentel, Claire

    2014-12-01

    Chronic concentrations of polycyclic aromatic hydrocarbons (PAHs) have been commonly detected in international estuaries ecosystems. Reliable indicators still need to be found in order to properly assess the impact of PAHs in fish. After an in vivo chronic exposure to hydrocarbons, the enzymatic activity of 7-ethoxyresorufin O-deethylase (EROD) and the antioxidant defense system were assessed in sea bass, Dicentrarchus labrax. A total of 45 fish were exposed to the water-soluble fraction of Arabian crude oil, similar to a complex pollution by hydrocarbons chronically observed in situ, while 45 other control fish sustained the same experimental conditions in clean seawater. Fish samples were made after a 21-day exposure period and after a 15-day recovery period in clean fresh water. Throughout the experiment, liver EROD activity was significantly higher in contaminated fish than in control fish. In addition, nonenzymatic (total glutathione) and enzymatic (GPx, SOD, and CAT) antioxidant defense parameters measured in liver were not significantly different in fish. Furthermore, in gills, glutathione content had significantly increased while SOD activity had significantly decreased in contaminated fish compared to controls. On the other hand, CAT and GPx activities were not affected. Chronic exposure to PAHs disturbing the first step (SOD) and inhibiting the second step (GPx and CAT) could induce oxidative stress in tissues by the formation of oxygen radicals. After the postexposure period, there was no significant difference between control and contaminated fish in any of the antioxidant defense parameters measured in gills, attesting to the reversibility of the effects.

  11. Gamma Band Activity in the RAS-intracellular mechanisms

    PubMed Central

    Garcia-Rill, E.; Kezunovic, N.; D’Onofrio, S.; Luster, B.; Hyde, J.; Bisagno, V.; Urbano, F.J.

    2014-01-01

    Gamma band activity participates in sensory perception, problem solving, and memory. This review considers recent evidence showing that cells in the reticular activating system (RAS) exhibit gamma band activity, and describes the intrinsic membrane properties behind such manifestation. Specifically, we discuss how cells in the mesopontine pedunculopontine nucleus (PPN), intralaminar parafascicular nucleus (Pf), and pontine Subcoeruleus nucleus dorsalis (SubCD) all fire in the gamma band range when maximally activated, but no higher. The mechanisms involve high threshold, voltage-dependent P/Q-type calcium channels or sodium-dependent subthreshold oscillations. Rather than participating in the temporal binding of sensory events as in the cortex, gamma band activity in the RAS may participate in the processes of preconscious awareness, and provide the essential stream of information for the formulation of many of our actions. We address three necessary next steps resulting from these discoveries, an intracellular mechanism responsible for maintaining gamma band activity based on persistent G-protein activation, separate intracellular pathways that differentiate between gamma band activity during waking vs during REM sleep, and an intracellular mechanism responsible for the dysregulation in gamma band activity in schizophrenia. These findings open several promising research avenues that have not been thoroughly explored. What are the effects of sleep or REM sleep deprivation on these RAS mechanisms? Are these mechanisms involved in memory processing during waking and/or during REM sleep? Does gamma band processing differ during waking vs REM sleep after sleep or REM sleep deprivation? PMID:24309750

  12. Solving the Dilemma of State Responses to Cyberattacks: A Justification for the use of Active Defenses Against States Who Neglect Their Duty to Prevent

    DTIC Science & Technology

    2009-04-01

    Security professionals can set up active defenses to automatically respond to attacks against critical systems, or can carry them out manually .158 For the...Michael Schmitt’s use of force analysis). 361 See WlNGFIELD, supra note 322, at 6-7; WlNGFIELD, supra note 48, at 115-29 (2000); Vida Antolin-Jenkins...criminal misuse of information technologies. See supra notes 382, 394-98, 400 and accompanying text; UNITED NATIONS MANUAL ON THE PREVENTION AND

  13. Mechanical Activation of Construction Binder Materials by Various Mills

    NASA Astrophysics Data System (ADS)

    Fediuk, R. S.

    2016-04-01

    The paper deals with the mechanical grinding down to the nano powder of construction materials. During mechanical activation a composite binder active molecules cement minerals occur in the destruction of the molecular defects in the areas of packaging and breaking metastable phase decompensation intermolecular forces. The process is accompanied by a change in the kinetics of hardening of portland cement. Mechanical processes during grinding mineral materials cause, along with the increase in their surface energy, increase the Gibbs energy of powders and, respectively, their chemical activity, which also contributes to the high adhesion strength when contacting them with binders. Thus, the set of measures for mechanical activation makes better use of the weight of components filled with cement systems and adjust their properties. At relatively low cost is possible to provide a spectacular and, importantly, easily repeatable results in a production environment.

  14. Investigation of oxidation process of mechanically activated ultrafine iron powders

    NASA Astrophysics Data System (ADS)

    Lysenko, E. N.; Nikolaev, E. V.; Vlasov, V. A.; Zhuravkov, S. P.

    2016-02-01

    The oxidation of mechanically activated ultrafine iron powders was studied using X- ray powder diffraction and thermogravimetric analyzes. The powders with average particles size of 100 nm were made by the electric explosion of wire, and were subjected to mechanical activation in planetary ball mill for 15 and 40 minutes. It was shown that a certain amount of FeO phase is formed during mechanical activation of ultrafine iron powders. According to thermogravimetric analysis, the oxidation process of non-milled ultrafine iron powders is a complex process and occurs in three stages. The preliminary mechanical activation of powders considerably changes the nature of the iron powders oxidation, leads to increasing in the temperature of oxidation onset and shifts the reaction to higher temperatures. For the milled powders, the oxidation is more simple process and occurs in a single step.

  15. Molecular mechanisms regulating the synergism between IL-32γ and NOD for the activation of eosinophils.

    PubMed

    Wong, Chun-Kwok; Dong, Jie; Lam, Christopher Wai-Kei

    2014-04-01

    IL-32 is a proinflammatory cytokine associated with infections, autoimmune diseases, and allergic asthma. In the present study, we elucidated the synergistic effect of IL-32γ and NOD ligand on the activation of human eosinophils, principal effector cells for allergic inflammation, and the underlying mechanisms. Specific IL-32-binding protein, PR3, was found to localize on the cell surface and in the cytoplasm of eosinophils. IL-32γ was more capable of activating eosinophils than its isotype variant IL-32α and exhibited synergistic effect with NOD1 ligand iE-DAP and NOD2 ligand MDP on the induction of allergic inflammation-related IL-1β, TNF-α, and chemokines CXCL8, CCL3, and CCL4 (P<0.05). Moreover, IL-32γ and iE-DAP or MDP induced the significant up-regulation of the cell-surface expression of adhesion molecule CD18 and ICAM-1 on eosinophils. Synergism between IL-32γ and NOD ligands was dependent on the activation of intracellular caspase 1, ERKs, p38 MAPK, and NF-κB pathways in eosinophils. The further-enhanced CD18 and ICAM-1 expression and production of cytokines and chemokines were observed in eosinophils cocultured with human bronchial epithelial BEAS-2B cells. Furthermore, combined treatment of IL-32γ and NOD ligand could activate the release of eosinophil extracellular DNA traps, thereby implying the pathogen-defense mechanisms of eosinophils. Together, the above study provides pivotal immunological mechanisms by which bacterial infection-mediated activation of NOD1,2, together with IL-32γ, can synergize the activation of eosinophils interacting with bronchial epithelial cells.

  16. Civil Defense, U. S. A.: A Programmed Orientation to Civil Defense. Unit 5. Governmental Responsibilities for Civil Defense.

    ERIC Educational Resources Information Center

    Defense Civil Preparedness Agency (DOD), Battle Creek, MI.

    A description of the laws and orders that provide necessary legal authorization for civil defense activities is provided. In addition, an outline of the responsibilities of all governments and the role of the private sector in civil defense is presented. Topics discussed include: (1) Legal authority for civil defense, (2) Civil defense…

  17. Tractor Mechanics: Learning Activity Packages 1-19.

    ERIC Educational Resources Information Center

    Clemson Univ., SC. Vocational Education Media Center.

    Learning activity packages are presented for teaching tractor mechanics. The first of two sections deals with miscellaneous tasks and contains learning activity packages on cleaning the tractor and receiving new tractor parts. Section 2 is concerned with maintaining and servicing the electrical system, and it includes the following learning…

  18. Elucidation of the Mechanism by Which Catecholamine Stress Hormones Liberate Iron from the Innate Immune Defense Proteins Transferrin and Lactoferrin ▿

    PubMed Central

    Sandrini, Sara M.; Shergill, Raminder; Woodward, Jonathan; Muralikuttan, Remya; Haigh, Richard D.; Lyte, Mark; Freestone, Primrose P.

    2010-01-01

    The ability of catecholamine stress hormones and inotropes to stimulate the growth of infectious bacteria is now well established. A major element of the growth induction process has been shown to involve the catecholamines binding to the high-affinity ferric-iron-binding proteins transferrin (Tf) and lactoferrin, which then enables bacterial acquisition of normally inaccessible sequestered host iron. The nature of the mechanism(s) by which the stress hormones perturb iron binding of these key innate immune defense proteins has not been fully elucidated. The present study employed electron paramagnetic resonance spectroscopy and chemical iron-binding analyses to demonstrate that catecholamine stress hormones form direct complexes with the ferric iron within transferrin and lactoferrin. Moreover, these complexes were shown to result in the reduction of Fe(III) to Fe(II) and the loss of protein-complexed iron. The use of bacterial ferric iron uptake mutants further showed that both the Fe(II) and Fe(III) released from the Tf could be directly used as bacterial nutrient sources. We also analyzed the transferrin-catecholamine interactions in human serum and found that therapeutically relevant concentrations of stress hormones and inotropes could directly affect the iron binding of serum-transferrin so that the normally highly bacteriostatic tissue fluid became significantly more supportive of the growth of bacteria. The relevance of these catecholamine-transferrin/lactoferrin interactions to the infectious disease process is considered. PMID:19820086

  19. Knockout of Arabidopsis ACCELERATED-CELL-DEATH11 encoding a sphingosine transfer protein causes activation of programmed cell death and defense

    PubMed Central

    Brodersen, Peter; Petersen, Morten; Pike, Helen M.; Olszak, Brian; Skov, Søren; Ødum, Niels; Jørgensen, Lise Bolt; Brown, Rhoderick E.; Mundy, John

    2002-01-01

    We describe the lethal, recessive accelerated-cell-death11 Arabidopsis mutant (acd11). Cell death in acd11 exhibits characteristics of animal apoptosis monitored by flow cytometry, and acd11 constitutively expresses defense-related genes that accompany the hypersensitive response normally triggered by avirulent pathogens. Global transcriptional changes during programmed cell death (PCD) and defense activation in acd11 were monitored by cDNA microarray hybridization. The PCD and defense pathways activated in acd11 are salicylic acid (SA) dependent, but do not require intact jasmonic acid or ethylene signaling pathways. Light is required for PCD execution in acd11, as application of an SA-analog to SA-deficient acd11 induced death in the light, but not in the dark. Epistatic analysis showed that the SA-dependent pathways require two regulators of SA-mediated resistance responses, PAD4 and EDS1. Furthermore, acd11 PR1 gene expression, but not cell death, depends on the SA signal tranducer NPR1, suggesting that the npr1-1 mutation uncouples resistance responses and cell death in acd11. The acd11 phenotype is caused by deletion of the ACD11 gene encoding a protein homologous to a mammalian glycolipid transfer protein (GLTP). In contrast to GLTP, ACD11 accelerates the transfer of sphingosine, but not of glycosphingolipids, between membranes in vitro. PMID:11850411

  20. Origin and functional diversification of an amphibian defense peptide arsenal.

    PubMed

    Roelants, Kim; Fry, Bryan G; Ye, Lumeng; Stijlemans, Benoit; Brys, Lea; Kok, Philippe; Clynen, Elke; Schoofs, Liliane; Cornelis, Pierre; Bossuyt, Franky

    2013-01-01

    The skin secretion of many amphibians contains an arsenal of bioactive molecules, including hormone-like peptides (HLPs) acting as defense toxins against predators, and antimicrobial peptides (AMPs) providing protection against infectious microorganisms. Several amphibian taxa seem to have independently acquired the genes to produce skin-secreted peptide arsenals, but it remains unknown how these originated from a non-defensive ancestral gene and evolved diverse defense functions against predators and pathogens. We conducted transcriptome, genome, peptidome and phylogenetic analyses to chart the full gene repertoire underlying the defense peptide arsenal of the frog Silurana tropicalis and reconstruct its evolutionary history. Our study uncovers a cluster of 13 transcriptionally active genes, together encoding up to 19 peptides, including diverse HLP homologues and AMPs. This gene cluster arose from a duplicated gastrointestinal hormone gene that attained a HLP-like defense function after major remodeling of its promoter region. Instead, new defense functions, including antimicrobial activity, arose by mutation of the precursor proteins, resulting in the proteolytic processing of secondary peptides alongside the original ones. Although gene duplication did not trigger functional innovation, it may have subsequently facilitated the convergent loss of the original function in multiple gene lineages (subfunctionalization), completing their transformation from HLP gene to AMP gene. The processing of multiple peptides from a single precursor entails a mechanism through which peptide-encoding genes may establish new functions without the need for gene duplication to avoid adaptive conflicts with older ones.

  1. Review of Department of Defense Education Activity (DoDEA) Schools. Volume I: Main Report and Appendixes. IDA Paper.

    ERIC Educational Resources Information Center

    Wright, Richard K.

    During school year 1998-99, military leaders and parents expressed discontent about the quality of education in Department of Defense (DoD) dependent schools in Europe. Concerned that these education issues were having an adverse impact on the quality of life of military members and families in Europe, and were creating morale and potential…

  2. Aphid Feeding Activates Expression of a Transcriptome of Oxylipin-Based Defense Signals in Wheat Involved in Resistance to Herbivory

    PubMed Central

    SMITH, C. MICHAEL; LIU, XUMING; WANG, LIANG J.; LIU, XIANG; CHEN, MING-SHUN; STARKEY, SHARON; BAI, JIANFA

    2013-01-01

    Damage by the Russian wheat aphid (RWA), Diuraphis noxia, significantly reduces wheat and barley yields worldwide. In compatible interactions, virulent RWA populations flourish and susceptible plants suffer extensive leaf chlorophyll loss. In incompatible interactions, RWA reproduction and population growth are significantly reduced and RWA-related chlorophyll loss in resistant plants is minor. The objectives of this study were to develop an understanding of the molecular and phytochemical bases of RWA resistance in plants containing the Dnx resistance gene. Microarray, real-time polymerase chain reaction, and phytohormone assays were conducted to identify transcriptome components unique to RWA-infested Dnx plants and susceptible (Dn0) plants, and to identify and characterize putative genes involved in Dnx plant defense responses. We found that RWA-infested Dnx plants upregulated > 180 genes related to reactive oxygen species, signaling, pathogen defense, and arthropod allelochemical and physical defense. The expression of several of these genes in RWA-infested Dnx plants increased significantly from 6- to 24-h post infestation (hpi), but their expression in Dn0 plants, when present, was delayed until 48- to 96 hpi. Concentrations of 16- and 18-carbon fatty acids, trans-methyl-12-oxophytodienoic acid, and abscisic acid were significantly greater in Dnx foliage than in Dn0 foliage after RWA infestation, suggesting that Dnx RWA defense and resistance genes may be regulated via the oxylipin pathway. These findings provide a foundation for the elucidation of the molecular basis for compatible- and incompatible plant-aphid interactions. PMID:20229216

  3. Electronic Commerce: Case Analyses and Tools Utilized in the Accomplishment of Buying Activities Within the Department of Defense

    DTIC Science & Technology

    2004-09-01

    infrastructure (what supports the concept), electronic business or e- business processes (how the business is conducted), and electronic commerce ( Ecommerce ... Business transactions with the Federal Government have evolved with the utilization of a variety of Ecommerce tools such as Government Purchase...In an effort to improve the way of doing business , Department of Defense has developed several Ecommerce tools to help facilitate the

  4. PERCEIVED EFFECTIVENESS OF AMERICA’S DEFENSES

    DTIC Science & Technology

    considered in the analysis. These included the public’s estimate of effectiveness of active and passive defenses. Examination of the confidence in...passive defenses involved the evaluation of evacuation programs, shelter programs, problems of warning time, local civil defense efforts, cost effectiveness ...of the system, and evaluation of civil defense programs in relation to various types of weapons effects . All available empirical evidence on these

  5. The Economic Effects of Reduced Defense Spending

    DTIC Science & Technology

    1992-02-01

    DEFENSE EXPENDITURES ON THE LEVEL OF ECONOMIC ACTIVITY How Changes in Defense Spending Affect the Economy 5 Defining Alternative Paths for...EFFECTS OF REDUCED DEFENSE SPENDING The Congress of the United States Congressional Budget Office NOTES All years referred to when discussing...the effects of cuts in defense spending not only on the national economy but also on states, industries, and selected local areas. R. William

  6. Mycorrhiza-induced resistance and priming of plant defenses.

    PubMed

    Jung, Sabine C; Martinez-Medina, Ainhoa; Lopez-Raez, Juan A; Pozo, Maria J

    2012-06-01

    Symbioses between plants and beneficial soil microorganisms like arbuscular-mycorrhizal fungi (AMF) are known to promote plant growth and help plants to cope with biotic and abiotic stresses. Profound physiological changes take place in the host plant upon root colonization by AMF affecting the interactions with a wide range of organisms below- and above-ground. Protective effects of the symbiosis against pathogens, pests, and parasitic plants have been described for many plant species, including agriculturally important crop varieties. Besides mechanisms such as improved plant nutrition and competition, experimental evidence supports a major role of plant defenses in the observed protection. During mycorrhiza establishment, modulation of plant defense responses occurs thus achieving a functional symbiosis. As a consequence of this modulation, a mild, but effective activation of the plant immune responses seems to occur, not only locally but also systemically. This activation leads to a primed state of the plant that allows a more efficient activation of defense mechanisms in response to attack by potential enemies. Here, we give an overview of the impact on interactions between mycorrhizal plants and pathogens, herbivores, and parasitic plants, and we summarize the current knowledge of the underlying mechanisms. We focus on the priming of jasmonate-regulated plant defense mechanisms that play a central role in the induction of resistance by arbuscular mycorrhizas.

  7. Mechanical properties that influence antimicrobial peptide activity in lipid membranes.

    PubMed

    Marín-Medina, Nathaly; Ramírez, Diego Alejandro; Trier, Steve; Leidy, Chad

    2016-12-01

    Antimicrobial peptides are small amphiphilic proteins found in animals and plants as essential components of the innate immune system and whose function is to control bacterial infectious activity. In order to accomplish their function, antimicrobial peptides use different mechanisms of action which have been deeply studied in view of their potential exploitation to treat antibiotic-resistant bacterial infections. One of the main mechanisms of action of these peptides is the disruption of the bacterial membrane through pore formation, which, in some cases, takes place via a monomer to oligomer cooperative transition. Previous studies have shown that lipid composition, and the presence of exogenous components, such as cholesterol in model membranes or carotenoids in bacteria, can affect the potency of distinct antimicrobial peptides. At the same time, considering the membrane as a two-dimensional material, it has been shown that membrane composition defines its mechanical properties which might be relevant in many membrane-related processes. Nevertheless, the correlation between the mechanical properties of the membrane and antimicrobial peptide potency has not been considered according to the importance it deserves. The relevance of these mechanical properties in membrane deformation due to peptide insertion is reviewed here for different types of pores in order to elucidate if indeed membrane composition affects antimicrobial peptide activity by modulation of the mechanical properties of the membrane. This would also provide a better understanding of the mechanisms used by bacteria to overcome antimicrobial peptide activity.

  8. Shift in aggregation, ROS generation, antioxidative defense, lysozyme and acetylcholinesterase activities in the cells of an Indian freshwater sponge exposed to washing soda (sodium carbonate).

    PubMed

    Mukherjee, Soumalya; Ray, Mitali; Ray, Sajal

    2016-09-01

    Washing soda, chemically identified as anhydrous sodium carbonate, is a popular cleaning agent among the rural and urban populations of India which often contaminates the freshwater ponds and lakes, the natural habitat of sponge Eunapius carteri. Present investigation deals with estimation of cellular aggregation, generation of ROS and activities of antioxidant enzymes, lysozyme and acetylcholinesterase in the cells of E. carteri under the environmentally realistic concentrations of washing soda. Prolonged treatment of washing soda inhibited the degree of cellular aggregation. Experimental exposure of 8 and 16mg/l of sodium carbonate for 48h elevated the physiological level of reactive oxygen species (ROS) generation in the agranulocytes, semigranulocytes and granulocytes of E. carteri, whereas, treatment of 192h inhibited the ROS generation in three cellular morphotypes. Activities of superoxide dismutase, catalase and glutathione-S-transferase were recorded to be inhibited under prolonged exposure of washing soda. Washing soda mediated inhibition of ROS generation and depletion in the activities of antioxidant enzymes were indicative to an undesirable shift in cytotoxic status and antioxidative defense in E. carteri. Inhibition in the activity of lysozyme under the treatment of sodium carbonate was suggestive to a severe impairment of the innate immunological efficiency of E. carteri distributed in the washing soda contaminated habitat. Washing soda mediated inhibition in the activity of acetylcholinesterase indicated its neurotoxicity in E. carteri. Washing soda, a reported environmental contaminant, affected adversely the immunophysiological status of E. carteri with reference to cellular aggregation, oxidative stress, antioxidative defense, lysozyme and acetylcholinesterase activity.

  9. Scavenging iron: a novel mechanism of plant immunity activation by microbial siderophores.

    PubMed

    Aznar, Aude; Chen, Nicolas W G; Rigault, Martine; Riache, Nassima; Joseph, Delphine; Desmaële, Didier; Mouille, Grégory; Boutet, Stéphanie; Soubigou-Taconnat, Ludivine; Renou, Jean-Pierre; Thomine, Sébastien; Expert, Dominique; Dellagi, Alia

    2014-04-01

    Siderophores are specific ferric iron chelators synthesized by virtually all microorganisms in response to iron deficiency. We have previously shown that they promote infection by the phytopathogenic enterobacteria Dickeya dadantii and Erwinia amylovora. Siderophores also have the ability to activate plant immunity. We have used complete Arabidopsis transcriptome microarrays to investigate the global transcriptional modifications in roots and leaves of Arabidopsis (Arabidopsis thaliana) plants after leaf treatment with the siderophore deferrioxamine (DFO). Physiological relevance of these transcriptional modifications was validated experimentally. Immunity and heavy-metal homeostasis were the major processes affected by DFO. These two physiological responses could be activated by a synthetic iron chelator ethylenediamine-di(o-hydroxyphenylacetic) acid, indicating that siderophores eliciting activities rely on their strong iron-chelating capacity. DFO was able to protect Arabidopsis against the pathogenic bacterium Pseudomonas syringae pv tomato DC3000. Siderophore treatment caused local modifications of iron distribution in leaf cells visible by ferrocyanide and diaminobenzidine-H₂O₂ staining. Metal quantifications showed that DFO causes a transient iron and zinc uptake at the root level, which is presumably mediated by the metal transporter iron regulated transporter1 (IRT1). Defense gene expression and callose deposition in response to DFO were compromised in an irt1 mutant. Consistently, plant susceptibility to D. dadantii was increased in the irt1 mutant. Our work shows that iron scavenging is a unique mechanism of immunity activation in plants. It highlights the strong relationship between heavy-metal homeostasis and immunity.

  10. Scavenging Iron: A Novel Mechanism of Plant Immunity Activation by Microbial Siderophores1[C][W

    PubMed Central

    Aznar, Aude; Chen, Nicolas W.G.; Rigault, Martine; Riache, Nassima; Joseph, Delphine; Desmaële, Didier; Mouille, Grégory; Boutet, Stéphanie; Soubigou-Taconnat, Ludivine; Renou, Jean-Pierre; Thomine, Sébastien; Expert, Dominique; Dellagi, Alia

    2014-01-01

    Siderophores are specific ferric iron chelators synthesized by virtually all microorganisms in response to iron deficiency. We have previously shown that they promote infection by the phytopathogenic enterobacteria Dickeya dadantii and Erwinia amylovora. Siderophores also have the ability to activate plant immunity. We have used complete Arabidopsis transcriptome microarrays to investigate the global transcriptional modifications in roots and leaves of Arabidopsis (Arabidopsis thaliana) plants after leaf treatment with the siderophore deferrioxamine (DFO). Physiological relevance of these transcriptional modifications was validated experimentally. Immunity and heavy-metal homeostasis were the major processes affected by DFO. These two physiological responses could be activated by a synthetic iron chelator ethylenediamine-di(o-hydroxyphenylacetic) acid, indicating that siderophores eliciting activities rely on their strong iron-chelating capacity. DFO was able to protect Arabidopsis against the pathogenic bacterium Pseudomonas syringae pv tomato DC3000. Siderophore treatment caused local modifications of iron distribution in leaf cells visible by ferrocyanide and diaminobenzidine-H2O2 staining. Metal quantifications showed that DFO causes a transient iron and zinc uptake at the root level, which is presumably mediated by the metal transporter iron regulated transporter1 (IRT1). Defense gene expression and callose deposition in response to DFO were compromised in an irt1 mutant. Consistently, plant susceptibility to D. dadantii was increased in the irt1 mutant. Our work shows that iron scavenging is a unique mechanism of immunity activation in plants. It highlights the strong relationship between heavy-metal homeostasis and immunity. PMID:24501001

  11. Application of flexure structures to active and adaptive opto-mechanical mechanisms

    NASA Astrophysics Data System (ADS)

    Zago, Lorenzo; Genequand, Pierre M.; Kjelberg, Ivar; Morschel, Joseph

    1997-03-01

    Active and adaptive structures, also commonly called 'smart' structures, combine in one integrated system various functions such as load carrying and structural function, mechanical (cinematic) functions, sensing, control and actuating. Originally developed for high accuracy opto-mechanical applications, CSEM's technology of flexure structures and flexible mechanisms is particularly suited to solve many structural and mechanical issues found in such active/adaptive mechanisms. The paper illustrates some recent flexure structures developments at CSEM and outlines the comprehensive know-how involved in this technology. This comprises in particular the elaboration of optimal design guidelines, related to the geometry, kinematics and dynamics issues (for instance, the minimization of spurious high frequency effects), the evaluation and predictability of all performance quantities relevant to the utilization of flexure structures in space (reliability, fatigue, static and dynamic modeling, etc.). material issues and manufacturing procedures.

  12. Inhibition of mouth skeletal muscle relaxation by flavonoids of Cistus ladanifer L.: a plant defense mechanism against herbivores.

    PubMed

    Sosa, T; Chaves, N; Alias, J C; Escudero, J C; Henao, F; Gutiérrez-Merino, C

    2004-06-01

    Cistus ladanifer exudate is a potent inhibitor of the sarcoplasmic reticulum Ca2+-ATPase (Ca2+-pump) of rabbit skeletal muscle, a well-established model for active transport that plays a leading role in skeletal muscle relaxation. The low concentration of exudate needed to produce 50% of the maximum inhibition of the sarcoplasmic reticulum Ca2+-ATPase activity, 40-60 microg/ml, suggests that eating only a few milligrams of C. ladanifer leaves can impair the relaxation of the mouth skeletal muscle of herbivores, as the exudate reaches up to 140 mg/g of dry leaves in summer season. The flavonoid fraction of the exudate accounts fully for the functional impairment of the sarcoplasmic reticulum produced by the exudate (up to a dose of 250-300 microg/ml). The flavonoids present in this exudate impair the skeletal muscle sarcoplasmic reticulum function at two different levels: (i) by inhibition of the Ca2+-ATPase activity, and (ii) by decreasing the steady state ATP-dependent Ca2+-accumulation. Among the exudate flavonoids, apigenin and 3,7-di-O-methyl kaempferol are the most potent inhibitors of the skeletal muscle sarcoplasmic reticulum. We conclude that the flavonoids of this exudate can elicit an avoidance reaction of the herbivores eating C. ladanifer leaves through impairment of mouth skeletal muscle relaxation.

  13. Cellular and Molecular Mechanisms Underpinning Macrophage Activation during Remyelination

    PubMed Central

    Lloyd, Amy F.; Miron, Veronique E.

    2016-01-01

    Remyelination is an example of central nervous system (CNS) regeneration, whereby myelin is restored around demyelinated axons, re-establishing saltatory conduction and trophic/metabolic support. In progressive multiple sclerosis, remyelination is limited or fails altogether which is considered to contribute to axonal damage/loss and consequent disability. Macrophages have critical roles in both CNS damage and regeneration, such as remyelination. This diverse range in functions reflects the ability of macrophages to acquire tissue microenvironment-specific activation states. This activation is dynamically regulated during efficient regeneration, with a switch from pro-inflammatory to inflammation-resolution/pro-regenerative phenotypes. Although, some molecules and pathways have been implicated in the dynamic activation of macrophages, such as NFκB, the cellular and molecular mechanisms underpinning plasticity of macrophage activation are unclear. Identifying mechanisms regulating macrophage activation to pro-regenerative phenotypes may lead to novel therapeutic strategies to promote remyelination in multiple sclerosis. PMID:27446913

  14. Active vibration control using mechanical and electrical analogies

    NASA Astrophysics Data System (ADS)

    Torres-Perez, A.; Hassan, A.; Kaczmarczyk, S.; Picton, P.

    2016-05-01

    Mechanical-electrical analogous circuit models are widely used in electromechanical system design as they represent the function of a coupled electrical and mechanical system using an equivalent electrical system. This research uses electrical circuits to establish a discussion of simple active vibration control principles using two scenarios: an active vibration isolation system and an active dynamic vibration absorber (DVA) using a voice coil motor (VCM) actuator. Active control laws such as gain scheduling are intuitively explained using circuit analysis techniques. Active vibration control approaches are typically constraint by electrical power requirements. The electrical analogous is a fast approach for specifying power requirements on the experimental test platform which is based on a vibration shaker that provides the based excitation required for the single Degree- of-Freedom (1DoF) vibration model under study.

  15. Conservative Mechanisms of Extracellular Trap Formation by Annelida Eisenia andrei: Serine Protease Activity Requirement

    PubMed Central

    Ortmann, Weronika; Kolaczkowska, Elzbieta

    2016-01-01

    Formation of extracellular traps (ETs) capturing and immobilizing pathogens is now a well-established defense mechanism added to the repertoire of vertebrate phagocytes. These ETs are composed of extracellular DNA (extDNA), histones and antimicrobial proteins. Formation of mouse and human ETs depends on enzymes (i) facilitating decondensation of chromatin by citrullination of histones, and (ii) serine proteases degrading histones. In invertebrates, initial reports revealed existence of ETs composed of extDNA and histones, and here we document for the first time that also coelomocytes, immunocompetent cells of an earthworm Eisenia andrei, cast ETs which successfully trap bacteria in a reactive oxygen species (ROS)-dependent and -independent manner. Importantly, the formation of ETs was observed not only when coelomocytes were studied ex vivo, but also in vivo, directly in the earthworm coelom. These ETs were composed of extDNA, heat shock proteins (HSP27) and H3 histones. Furthermore, the formation of E. andrei ETs depended on activity of serine proteases, including elastase-like activity. Moreover, ETs interconnected and hold together aggregating coelomocytes, a processes proceeding encapsulation. In conclusion, the study confirms ET formation by earthworms, and unravels mechanisms leading to ET formation and encapsulation in invertebrates. PMID:27416067

  16. Bacterial Evasion of Host Antimicrobial Peptide Defenses

    PubMed Central

    Cole, Jason N.; Nizet, Victor

    2015-01-01

    SUMMARY Antimicrobial peptides (AMPs), also known as host defense peptides, are small naturally occurring microbicidal molecules produced by the host innate immune response that function as a first line of defense to kill pathogenic microorganisms by inducing deleterious cell membrane damage. AMPs also possess signaling and chemoattractant activities and can modulate the innate immune response to enhance protective immunity or suppress inflammation. Human pathogens have evolved defense molecules and strategies to counter and survive the AMPs released by host immune cells such as neutrophils and macrophages. Here, we review the various mechanisms used by human bacterial pathogens to resist AMP-mediated killing, including surface charge modification, active efflux, alteration of membrane fluidity, inactivation by proteolytic digestion, and entrapment by surface proteins and polysaccharides. Enhanced understanding of AMP resistance at the molecular level may offer insight into the mechanisms of bacterial pathogenesis and augment the discovery of novel therapeutic targets and drug design for the treatment of recalcitrant multidrug-resistant bacterial infections. PMID:26999396

  17. Mechanisms of Activation of Voltage-Gated Potassium Channels

    PubMed Central

    Grizel, A. V.; Glukhov, G. S.; Sokolova, O. S.

    2014-01-01

    Voltage-gated potassium ion channels (Kv) play an important role in a variety of cellular processes, including the functioning of excitable cells, regulation of apoptosis, cell growth and differentiation, the release of neurotransmitters and hormones, maintenance of cardiac activity, etc. Failure in the functioning of Kv channels leads to severe genetic disorders and the development of tumors, including malignant ones. Understanding the mechanisms underlying Kv channels functioning is a key factor in determining the cause of the diseases associated with mutations in the channels, and in the search for new drugs. The mechanism of activation of the channels is a topic of ongoing debate, and a consensus on the issue has not yet been reached. This review discusses the key stages in studying the mechanisms of functioning of Kv channels and describes the basic models of their activation known to date. PMID:25558391

  18. Activity of Uncleaved Caspase-8 Controls Anti-bacterial Immune Defense and TLR-Induced Cytokine Production Independent of Cell Death

    PubMed Central

    DeLaney, Alexandra; Santos-Marrero, Melanie; Grier, Jennifer T.; Sun, Yan; Zwack, Erin E.; Hu, Baofeng; Olsen, Tayla M.; Rongvaux, Anthony; López, Carolina B.; Oberst, Andrew; Beiting, Daniel P.; Brodsky, Igor E.

    2016-01-01

    Caspases regulate cell death programs in response to environmental stresses, including infection and inflammation, and are therefore critical for the proper operation of the mammalian immune system. Caspase-8 is necessary for optimal production of inflammatory cytokines and host defense against infection by multiple pathogens including Yersinia, but whether this is due to death of infected cells or an intrinsic role of caspase-8 in TLR-induced gene expression is unknown. Caspase-8 activation at death signaling complexes results in its autoprocessing and subsequent cleavage and activation of its downstream apoptotic targets. Whether caspase-8 activity is also important for inflammatory gene expression during bacterial infection has not been investigated. Here, we report that caspase-8 plays an essential cell-intrinsic role in innate inflammatory cytokine production in vivo during Yersinia infection. Unexpectedly, we found that caspase-8 enzymatic activity regulates gene expression in response to bacterial infection as well as TLR signaling independently of apoptosis. Using newly-generated mice in which caspase-8 autoprocessing is ablated (Casp8DA/DA), we now demonstrate that caspase-8 enzymatic activity, but not autoprocessing, mediates induction of inflammatory cytokines by bacterial infection and a wide variety of TLR stimuli. Because unprocessed caspase-8 functions in an enzymatic complex with its homolog cFLIP, our findings implicate the caspase-8/cFLIP heterodimer in control of inflammatory cytokines during microbial infection, and provide new insight into regulation of antibacterial immune defense. PMID:27737018

  19. Epigenetic Control of Defense Signaling and Priming in Plants.

    PubMed

    Espinas, Nino A; Saze, Hidetoshi; Saijo, Yusuke

    2016-01-01

    Immune recognition of pathogen-associated molecular patterns or effectors leads to defense activation at the pathogen challenged sites. This is followed by systemic defense activation at distant non-challenged sites, termed systemic acquired resistance (SAR). These inducible defenses are accompanied by extensive transcriptional reprogramming of defense-related genes. SAR is associated with priming, in which a subset of these genes is kept at a poised state to facilitate subsequent transcriptional regulation. Transgenerational inheritance of defense-related priming in plants indicates the stability of such primed states. Recent studies have revealed the importance and dynamic engagement of epigenetic mechanisms, such as DNA methylation and histone modifications that are closely linked to chromatin reconfiguration, in plant adaptation to different biotic stresses. Herein we review current knowledge regarding the biological significance and underlying mechanisms of epigenetic control for immune responses in plants. We also argue for the importance of host transposable elements as critical regulators of interactions in the evolutionary "arms race" between plants and pathogens.

  20. Epigenetic Control of Defense Signaling and Priming in Plants

    PubMed Central

    Espinas, Nino A.; Saze, Hidetoshi; Saijo, Yusuke

    2016-01-01

    Immune recognition of pathogen-associated molecular patterns or effectors leads to defense activation at the pathogen challenged sites. This is followed by systemic defense activation at distant non-challenged sites, termed systemic acquired resistance (SAR). These inducible defenses are accompanied by extensive transcriptional reprogramming of defense-related genes. SAR is associated with priming, in which a subset of these genes is kept at a poised state to facilitate subsequent transcriptional regulation. Transgenerational inheritance of defense-related priming in plants indicates the stability of such primed states. Recent studies have revealed the importance and dynamic engagement of epigenetic mechanisms, such as DNA methylation and histone modifications that are closely linked to chromatin reconfiguration, in plant adaptation to different biotic stresses. Herein we review current knowledge regarding the biological significance and underlying mechanisms of epigenetic control for immune responses in plants. We also argue for the importance of host transposable elements as critical regulators of interactions in the evolutionary “arms race” between plants and pathogens. PMID:27563304

  1. New insight into the effects of lead modulation on antioxidant defense mechanism and trace element concentration in rat bone.

    PubMed

    Payal, Bhardwaj; Kaur, Harkiran Preet; Rai, Durg Vijay

    2009-03-01

    Risks of heavy metals-induced severe bone disorders generate interest to their toxicity. The present study was undertaken to monitor the biochemical and antioxidant status of bone of 30 and 80 days old male Wistar rats exposed to 5 week lead treatment. At the end of study, the rats were sacrificed, their long bone i.e. femur were excised, cleaned of soft tissue, minced and homogenized. Nucleic acid content, alkaline phosphatase, lipid peroxidation, catalase, glutathione S-transferase and superoxide dismutase were determined in bone. In both groups of treated animals lead treatment increased the production of malondialdehyde, while reducing activities of catalase, glutathione S-transferase and superoxide dismutase, indicating that it causes oxidative stress. Parallely with these effects lead significantly reduced the nucleic acid content and the activity of alkaline phosphatase, considered as biomarkers of osteoblast's function, conditions and development of bones. Moreover the concentrations of copper, zinc, iron and sodium were reduced in the excised bones. The present study indicates that the lead induced bone toxicity and its deteriorated development is the consequence of a primary oxidative stress. Our results may be helpful in understanding the modulation of biochemical parameters under lead toxicity.

  2. Innovative Application of Mechanical Activation for Rare Earth Elements Recovering: Process Optimization and Mechanism Exploration

    PubMed Central

    Tan, Quanyin; Deng, Chao; Li, Jinhui

    2016-01-01

    With the rapidly expanding use of fluorescent lamps (FLs) and increasing interest in conservation and sustainable utilization of critical metals such as rare earth elements (REEs), the recovering of REEs from phosphors in waste FLs is becoming a critical environmental and economic issue. To effectively recycle REEs with metallurgical methods, mechanical activation by ball milling was introduced to pretreat the waste phosphors. This current study put the emphasis on the mechanical activation and leaching processes for REEs, and explored the feasibility of the method from both theoretical and practical standpoints. Results showed physicochemical changes of structural destruction and particle size reduction after mechanical activation, leading to the easy dissolution of REEs in the activated samples. Under optimal conditions, dissolution yields of 89.4%, 93.1% and 94.6% for Tb, Eu and Y, respectively, were achieved from activated waste phosphors using hydrochloric acid as the dissolution agent. The shrinking core model proved to be the most applicable for the leaching procedure, with an apparent activation energy of 10.96 ± 2.79 kJ/mol. This novel process indicates that mechanical activation is an efficient method for recovering REEs from waste phosphors, and it has promising potential for REE recovery with low cost and high efficiency. PMID:26819083

  3. Innovative Application of Mechanical Activation for Rare Earth Elements Recovering: Process Optimization and Mechanism Exploration

    NASA Astrophysics Data System (ADS)

    Tan, Quanyin; Deng, Chao; Li, Jinhui

    2016-01-01

    With the rapidly expanding use of fluorescent lamps (FLs) and increasing interest in conservation and sustainable utilization of critical metals such as rare earth elements (REEs), the recovering of REEs from phosphors in waste FLs is becoming a critical environmental and economic issue. To effectively recycle REEs with metallurgical methods, mechanical activation by ball milling was introduced to pretreat the waste phosphors. This current study put the emphasis on the mechanical activation and leaching processes for REEs, and explored the feasibility of the method from both theoretical and practical standpoints. Results showed physicochemical changes of structural destruction and particle size reduction after mechanical activation, leading to the easy dissolution of REEs in the activated samples. Under optimal conditions, dissolution yields of 89.4%, 93.1% and 94.6% for Tb, Eu and Y, respectively, were achieved from activated waste phosphors using hydrochloric acid as the dissolution agent. The shrinking core model proved to be the most applicable for the leaching procedure, with an apparent activation energy of 10.96 ± 2.79 kJ/mol. This novel process indicates that mechanical activation is an efficient method for recovering REEs from waste phosphors, and it has promising potential for REE recovery with low cost and high efficiency.

  4. Innovative Application of Mechanical Activation for Rare Earth Elements Recovering: Process Optimization and Mechanism Exploration.

    PubMed

    Tan, Quanyin; Deng, Chao; Li, Jinhui

    2016-01-28

    With the rapidly expanding use of fluorescent lamps (FLs) and increasing interest in conservation and sustainable utilization of critical metals such as rare earth elements (REEs), the recovering of REEs from phosphors in waste FLs is becoming a critical environmental and economic issue. To effectively recycle REEs with metallurgical methods, mechanical activation by ball milling was introduced to pretreat the waste phosphors. This current study put the emphasis on the mechanical activation and leaching processes for REEs, and explored the feasibility of the method from both theoretical and practical standpoints. Results showed physicochemical changes of structural destruction and particle size reduction after mechanical activation, leading to the easy dissolution of REEs in the activated samples. Under optimal conditions, dissolution yields of 89.4%, 93.1% and 94.6% for Tb, Eu and Y, respectively, were achieved from activated waste phosphors using hydrochloric acid as the dissolution agent. The shrinking core model proved to be the most applicable for the leaching procedure, with an apparent activation energy of 10.96 ± 2.79 kJ/mol. This novel process indicates that mechanical activation is an efficient method for recovering REEs from waste phosphors, and it has promising potential for REE recovery with low cost and high efficiency.

  5. Modulation of bone remodeling via mechanically activated ion channels

    NASA Technical Reports Server (NTRS)

    Duncan, Randall L. (Principal Investigator)

    1996-01-01

    A critical factor in the maintenance of bone mass is the physical forces imposed upon the skeleton. Removal of these forces, such as in a weightless environment, results in a rapid loss of bone, whereas application of exogenous mechanical strain has been shown to increase bone formation. Numerous flight and ground-based experiments indicate that the osteoblast is the key bone cell influenced by mechanical stimulation. Aside from early transient fluctuations in response to unloading, osteoclast number and activity seem unaffected by removal of strain. However, bone formation is drastically reduced in weightlessness and osteoblasts respond to mechanical strain with an increase in the activity of a number of second messenger pathways resulting in increased anabolic activity. Unfortunately, the mechanism by which the osteoblast converts physical stimuli into a biochemical message, a process we have termed biochemical coupling, remains elusive. Prior to the application of this grant, we had characterized a mechanosensitive, cation nonselective channel (SA-cat) in osteoblast-like osteosarcoma cells that we proposed is the initial signalling mechanism for mechanotransduction. During the execution of this grant, we have made considerable progress to further characterize this channel as well as to determine its role in the osteoblastic response to mechanical strain. To achieve these goals, we combined electrophysiologic techniques with cellular and molecular biology methods to examine the role of these channels in the normal function of the osteoblast in vitro.

  6. Small molecules reveal an alternative mechanism of Bax activation

    PubMed Central

    Brahmbhatt, Hetal; Uehling, David; Al-awar, Rima; Leber, Brian; Andrews, David

    2016-01-01

    The pro-apoptotic protein Bax commits a cell to death by permeabilizing the mitochondrial outer membrane (MOM). To obtain small-molecule probes for elucidating the molecular mechanism(s) of Bax activation, we screened for compounds that induced Bax-mediated liposome permeabilization. We identified five structurally different small molecules that promoted both Bax targeting to and oligomerization at membranes. All five compounds initiated Bax oligomerization in the absence of membranes by a mechanism unlike Bax activation by Bcl-2 homology 3 domain (BH3) proteins. Some of the compounds induced Bax/Bak-dependent apoptosis in cells. Activation of Bax by the most active compound was poorly inhibited by the anti-apoptotic protein Bcl-XL and requires a cysteine residue at position 126 of Bax that is not required for activation by BH3 proteins. Our results reveal a novel pathway for Bax activation independent of pro-apoptotic BH3 proteins that may have important implications for the regulation of Bax activity in cells. PMID:26916338

  7. The mechanical and tribological properties of UHMWPE loaded ALN after mechanical activation for joint replacements.

    PubMed

    Gong, Kemeng; Qu, Shuxin; Liu, Yumei; Wang, Jing; Zhang, Yongchao; Jiang, Chongxi; Shen, Ru

    2016-08-01

    Ultra-high molecular weight polyethylene (UHMWPE) loaded with alendronate sodium (ALN) has tremendous potential as an orthopeadic biomaterial for joint replacements. However, poor mechanical and tribological properties of UHMWPE-ALN are still obstacle for further application. The purpose of this study was to investigate the effect and mechanism of mechanical activation on mechanical and tribological properties of 1wt% ALN-loaded UHMWPE (UHMWPE-ALN-ma). In this study, tensile test, small punch test and reciprocating sliding wear test were applied to characterize the mechanical and tribological properties of UHMWPE-ALN-ma. Scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and Fourier transform infrared spectroscopy (FTIR) were employed to characterize UHMWPE-ALN-ma. Tensile test and small punch test showed that Young׳s modulus, tensile strength and work-to-failure (WTF) of UHMWPE-ALN-ma increased significantly compared to those of UHMWPE-ALN. The friction coefficients and wear factors of UHMWPE-ALN-ma both decreased significantly compared to those of UHMWPE-ALN. Mechanical activation obviously reduced type 1 (void) and type 2 (the disconnected and dislocated machining marks) fusion defects of UHMWPE-ALN-ma, which were revealed by SEM images of freeze fracture surfaces after etching and lateral surfaces of specimens after extension to fracture, respectively. It was attributed to peeled-off layers and chain scission of molecular chains of UHMWPE particles after mechanical activation, which were revealed by SEM images and FTIR spectra of UHMWPE-ALN-ma and UHMWPE-ALN, respectively. Moreover, EDS spectra revealed the more homogeneous distribution of ALN in UHMWPE-ALN-ma compared to that of UHMWPE-ALN. The present results showed that mechanical activation was a potential strategy to improve mechanical and tribological properties of UHMWPE-ALN-ma as an orthopeadic biomaterial for joint replacements.

  8. A Diverse Family of Host-Defense Peptides (Piscidins) Exhibit Specialized Anti-Bacterial and Anti-Protozoal Activities in Fishes

    PubMed Central

    Cassady, Katherine R.; Noga, Edward J.

    2016-01-01

    Conventional antibiotics and other chemical-based drugs are currently one of the most common methods used to control disease-related mortality in animal agriculture. Use of the innate immune system to decrease disease related mortalities is a novel alternative to conventional drugs. One component of the innate immune system is the host-defense peptides, also known as antimicrobial peptides. Host-defense peptides are typically small, amphipathic, α-helical peptides with a broad-spectrum of action against viral, bacterial, fungal, and/or protozoal pathogens. Piscidins are host-defense peptides first discovered in the hybrid striped bass (white bass, Morone chrysops, x striped bass, M. saxatilis). In this paper we identify four new piscidin isoforms in the hybrid striped bass and describe their tissue distributions. We also determine the progenitor species of origin of each piscidin (orthology) and propose a revised nomenclature for this newly described piscidin family based on a three class system. The Class I piscidins (22 amino acids in length; striped bass and white bass piscidin 1 and piscidin 3) show broad-spectrum activity against bacteria and ciliated protozoans, while the Class III piscidins (55 amino acids in length; striped bass and white bass piscidin 6 and striped bass piscidin 7) primarily show anti-protozoal activity. The Class II piscidins (44–46 amino acids in length; striped bass and white bass piscidin 4 and white bass piscidin 5) have a level of activity against bacteria and protozoans intermediate to Classes I and III. Knowledge of piscidin function and activity may help in the future development of disease-resistant lines of striped bass and white bass that could be used to produce superior hybrids for aquaculture. PMID:27552222

  9. Possible role of macrophages induced by an irridoid glycoside (RLJ-NE-299A) in host defense mechanism.

    PubMed

    Sidiq, Tabasum; Khajuria, Anamika; Suden, Pankaj; Sharma, Rohit; Singh, Surjeet; Suri, K A; Satti, N K; Johri, R K

    2011-01-01

    In order to explore the possible role of macrophages and other necessary immune competent (T and B) cells in the modulation of immune responses, an attempt was made to study the immunomodulatory effect of an irridoid glycoside (RLJ-NE-299A) isolated from the roots of Picrorhiza kurroa. Both in vitro and in vivo studies were used to evaluate the effect of RLJ-NE-299A on humoral, cellular, and phagocytic activity of macrophages. The data obtained in the present study showed that RLJ-NE-299A significantly increased sheep red blood cell (SRBC) and induced antibody (IgM and IgG) titer and delayed type hypersensitivity (DTH) reaction in mice. Besides augmenting the humoral and cell-mediated immune response, it induced macrophage phagocytosis and stimulated cytokine-induced macrophage activation and nitric oxide (NO) production, which resulted in a high degree of protection against Candida albicans and Salmonella typhimurium infections. Flow cytometric analysis indicated the enhanced expression of co-stimulatory surface molecules CD80 and CD86. The ability of RLJ-NE-299A to upregulate these cell surface antigens involved in antigen presentation may provide an explanation for the increased T-cell mediated immunity involving macrophages. Taken together this in vitro and in vivo preclinical data suggests that RLJ-NE-299A acts as an effective immunomodulator specifically to improve macrophage function during infections. The effects of this agent on these cells at concentrations relevant to in vivo therapy support its immunopharmacologic application to modify cellular immunity.

  10. Maintaining tissue selenium species distribution as a potential defense mechanism against methylmercury toxicity in juvenile white sturgeon (Acipenser transmontanus).

    PubMed

    Huang, Susie Shih-Yin; Hung, Silas S O; Chan, Hing Man

    2014-11-01

    Selenium (Se) has been shown to antagonize mercury (Hg) toxicity. We have previously demonstrated that orally intubated selenomethionine (SeMet) and methylmercury (MeHg) reduced tissue Se accumulation, as well as blood and kidney Hg concentrations in juvenile white sturgeon (Acipenser transmontanus). However, the form of Se accumulated is not known. In this study, three organoseleniums: selenocysteine (Sec), Se-methyl-selenocysteine (MSeCys), and SeMet and two inorganic Se species: selenate and selenite were determined and quantified in the blood at different post-intubation periods (12, 24, 48h) and in the muscle, liver, and kidneys at 48h in white sturgeon orally intubated with a single dose of control (carrier), SeMet (500μg Se/kg body weight; BW), MeHg (850μg Hg/kg BW), and both (Se+Hg; at 500μg Se/kg and 850μg Hg/kg BW). When only SeMet was intubated, the accumulative/unmodified pathway took precedent in the blood, white muscle, liver, and kidneys. In the presence of MeHg, however, active metabolic transformation and de novo synthesis of biologically active Se forms are seen in the liver and kidneys, as indicated by a gradual increase in blood Sec:SeMet ratios and Se metabolites. In the white muscle, mobilization of endogenous Se storage by MeHg is supported by the absence of tissue SeMet and detectable levels of blood SeMet. In contrast, co-intubation with SeMet increased muscle SeMet. The high levels of unknown Se metabolites and detectable levels of selenite in the kidney reflect its role as the major excretory organ for Se. Selenium metabolism is highly regulated in the kidneys, as Se speciation was not affected by MeHg or by its co-intubation with SeMet. In the Se+Hg group, the proportion of SeMet in the liver has decreased to nearly 1/8th of that of the SeMet only group, resulting in a more similar selenocompound distribution profile to that of the MeHg only group. This is likely due to the increased need for Se metabolites necessary for Me

  11. Secured network sensor-based defense system

    NASA Astrophysics Data System (ADS)

    Wei, Sixiao; Shen, Dan; Ge, Linqiang; Yu, Wei; Blasch, Erik P.; Pham, Khanh D.; Chen, Genshe

    2015-05-01

    Network sensor-based defense (NSD) systems have been widely used to defend against cyber threats. Nonetheless, if the adversary finds ways to identify the location of monitor sensors, the effectiveness of NSD systems can be reduced. In this paper, we propose both temporal and spatial perturbation based defense mechanisms to secure NSD systems and make the monitor sensor invisible to the adversary. The temporal-perturbation based defense manipulates the timing information of published data so that the probability of successfully recognizing monitor sensors can be reduced. The spatial-perturbation based defense dynamically redeploys monitor sensors in the network so that the adversary cannot obtain the complete information to recognize all of the monitor sensors. We carried out experiments using real-world traffic traces to evaluate the effectiveness of our proposed defense mechanisms. Our data shows that our proposed defense mechanisms can reduce the attack accuracy of recognizing detection sensors.

  12. Active Cyber Defense: Enhancing National Cyber Defense

    DTIC Science & Technology

    2011-12-01

    this is the Zeus Trojan.25 4. Zero-Day Attacks These attacks occur when an attacker (humans or artificial-intelligence controlled malware...www.shadowserver.org/wiki/pmwiki.php/Information/Botnets. 24 “Glossary,” McAfee, http://home.mcafee.com/VirusInfo/Glossary.aspx. 25 Elinor Mills, “ Zeus Trojan Steals...Institute, November 2005. http://www.cert.org/archive/pdf/05tr009.pdf. Mills, Elinor. “ Zeus Trojan steals $1 million from U.K. bank accounts.” CNET, 10

  13. Mechanisms of active control for noise inside a vibrating cylinder

    NASA Technical Reports Server (NTRS)

    Lester, Harold C.; Fuller, Chris R.

    1987-01-01

    The active control of propeller-induced noise fields inside a flexible cylinder is studied with attention given to the noise reduction mechanisms inherent in the present coupled acoustic shell model. The active noise control model consists of an infinitely long aluminum cylinder with a radius of 0.4 m and a thickness of 0.001 m. Pressure maps are shown when the two external sources are driven in-phase at a frequency corresponding to Omega = 0.22.

  14. Investigating Therapeutic Potential of Trigonella foenum-graecum L. as Our Defense Mechanism against Several Human Diseases

    PubMed Central

    Goyal, Shivangi; Gupta, Nidhi; Chatterjee, Sreemoyee

    2016-01-01

    Current lifestyle, stress, and pollution have dramatically enhanced the progression of several diseases in human. Globally, scientists are looking for therapeutic agents that can either cure or delay the onset of diseases. Medicinal plants from time immemorial have been used frequently in therapeutics. Of many such plants, fenugreek is one of the oldest herbs which have been identified as an important medicinal plant by the researchers around the world. It is potentially beneficial in a number of diseases such as diabetes, hypercholesterolemia, and inflammation and probably in several kinds of cancers. It has industrial applications such as synthesis of steroidal hormones. Its medicinal properties and their role in clinical domain can be attributed to its chemical constituents. The 3 major chemical constituents which have been identified as responsible for principle health effects are galactomannan, 4-OH isoleucine, and steroidal saponin. Numerous experiments have been carried out in vivo and in vitro for beneficial effects of both the crude chemical and of its active constituent. Due to its role in health care, the functional food industry has referred to it as a potential nutraceutical. This paper is about various medicinal benefits of fenugreek and its potential application as therapeutic agent against several diseases. PMID:26884758

  15. Control of plant defense mechanisms and fire blight pathogenesis through the regulation of 6-thioguanine biosynthesis in Erwinia amylovora.

    PubMed

    Coyne, Sébastien; Litomska, Agnieszka; Chizzali, Cornelia; Khalil, Mohammed N A; Richter, Klaus; Beerhues, Ludger; Hertweck, Christian

    2014-02-10

    Fire blight is a devastating disease of Rosaceae plants, such as apple and pear trees. It is characterized by necrosis of plant tissue, caused by the phytopathogenic bacterium Erwinia amylovora. The plant pathogen produces the well-known antimetabolite 6-thioguanine (6TG), which plays a key role in fire blight pathogenesis. Here we report that YcfR, a member of the LTTR family, is a major regulator of 6TG biosynthesis in E. amylovora. Inactivation of the regulator gene (ycfR) led to dramatically decreased 6TG production. Infection assays with apple plants (Malus domestica cultivar Holsteiner Cox) and cell cultures of Sorbus aucuparia (mountain ash, rowan) revealed abortive fire blight pathogenesis and reduced plant response (biphenyl and dibenzofuran phytoalexin production). In the presence of the ΔycfR mutant, apple trees were capable of activating the abscission machinery to remove infected tissue. In addition to unveiling the regulation of 6TG biosynthesis in a major plant pathogen, we demonstrate for the first time that this antimetabolite plays a pivotal role in dysregulating the plant response to infection.

  16. A new autocatalytic activation mechanism for cysteine proteases revealed by Prevotella intermedia interpain A.

    PubMed

    Mallorquí-Fernández, Noemí; Manandhar, Surya P; Mallorquí-Fernández, Goretti; Usón, Isabel; Wawrzonek, Katarzyna; Kantyka, Tomasz; Solà, Maria; Thøgersen, Ida B; Enghild, Jan J; Potempa, Jan; Gomis-Rüth, F Xavier

    2008-02-01

    Prevotella intermedia is a major periodontopathogen contributing to human gingivitis and periodontitis. Such pathogens release proteases as virulence factors that cause deterrence of host defenses and tissue destruction. A new cysteine protease from the cysteine-histidine-dyad class, interpain A, was studied in its zymogenic and self-processed mature forms. The latter consists of a bivalved moiety made up by two subdomains. In the structure of a catalytic cysteine-to-alanine zymogen variant, the right subdomain interacts with an unusual prodomain, thus contributing to latency. Unlike the catalytic cysteine residue, already in its competent conformation in the zymogen, the catalytic histidine is swung out from its active conformation and trapped in a cage shaped by a backing helix, a zymogenic hairpin, and a latency flap in the zymogen. Dramatic rearrangement of up to 20A of these elements triggered by a tryptophan switch occurs during activation and accounts for a new activation mechanism for proteolytic enzymes. These findings can be extrapolated to related potentially pathogenic cysteine proteases such as Streprococcus pyogenes SpeB and Porphyromonas gingivalis periodontain.

  17. Hydrogen-Rich Water Intake Accelerates Oral Palatal Wound Healing via Activation of the Nrf2/Antioxidant Defense Pathways in a Rat Model

    PubMed Central

    Orihuela-Campos, Rita Cristina; Fukui, Makoto; Ito, Hiro-O

    2016-01-01

    The wound healing process attempts to restore the integrity and function of the injured tissue. Additionally, proinflammatory cytokines, growth factors, and oxidative stress play important roles in wound healing. The aim of this study was to determine whether hydrogen-rich water intake induces the activation of the Nrf2/antioxidant defense pathway in rat palatal tissue, thereby reducing systemic oxidative stress and proinflammatory cytokine levels and promoting healing-associated genes. A circular excisional wound was created in the oral palatal region, and the wound healing process was observed. The rats were divided into two experimental groups in which either hydrogen-rich water or distilled water was consumed. In the drinking hydrogen-rich water, the palatal wound healing process was accelerated compared to that in the control group. As molecular hydrogen upregulated the Nrf2 pathway, systemic oxidative stresses were decreased by the activation of antioxidant activity. Furthermore, hydrogen-rich water intake reduced proinflammatory cytokine levels and promoted the expression of healing-associated factors in rat palatal tissue. In conclusion, hydrogen-rich water intake exhibited multiple beneficial effects through activation of the Nrf2/antioxidant defense pathway. The results of this study support the hypothesis that oral administration of hydrogen-rich water benefits the wound healing process by decreasing oxidative stress and inflammatory responses. PMID:26798423

  18. Hydrogen-Rich Water Intake Accelerates Oral Palatal Wound Healing via Activation of the Nrf2/Antioxidant Defense Pathways in a Rat Model.

    PubMed

    Tamaki, Naofumi; Orihuela-Campos, Rita Cristina; Fukui, Makoto; Ito, Hiro-O

    2016-01-01

    The wound healing process attempts to restore the integrity and function of the injured tissue. Additionally, proinflammatory cytokines, growth factors, and oxidative stress play important roles in wound healing. The aim of this study was to determine whether hydrogen-rich water intake induces the activation of the Nrf2/antioxidant defense pathway in rat palatal tissue, thereby reducing systemic oxidative stress and proinflammatory cytokine levels and promoting healing-associated genes. A circular excisional wound was created in the oral palatal region, and the wound healing process was observed. The rats were divided into two experimental groups in which either hydrogen-rich water or distilled water was consumed. In the drinking hydrogen-rich water, the palatal wound healing process was accelerated compared to that in the control group. As molecular hydrogen upregulated the Nrf2 pathway, systemic oxidative stresses were decreased by the activation of antioxidant activity. Furthermore, hydrogen-rich water intake reduced proinflammatory cytokine levels and promoted the expression of healing-associated factors in rat palatal tissue. In conclusion, hydrogen-rich water intake exhibited multiple beneficial effects through activation of the Nrf2/antioxidant defense pathway. The results of this study support the hypothesis that oral administration of hydrogen-rich water benefits the wound healing process by decreasing oxidative stress and inflammatory responses.

  19. Multivariable Dynamic Ankle Mechanical Impedance With Active Muscles

    PubMed Central

    Lee, Hyunglae; Krebs, Hermano Igo; Hogan, Neville

    2015-01-01

    Multivariable dynamic ankle mechanical impedance in two coupled degrees-of-freedom (DOFs) was quantified when muscles were active. Measurements were performed at five different target activation levels of tibialis anterior and soleus, from 10% to 30% of maximum voluntary contraction (MVC) with increments of 5% MVC. Interestingly, several ankle behaviors characterized in our previous study of the relaxed ankle were observed with muscles active: ankle mechanical impedance in joint coordinates showed responses largely consistent with a second-order system consisting of inertia, viscosity, and stiffness; stiffness was greater in the sagittal plane than in the frontal plane at all activation conditions for all subjects; and the coupling between dorsiflexion–plantarflexion and inversion–eversion was small—the two DOF measurements were well explained by a strictly diagonal impedance matrix. In general, ankle stiffness increased linearly with muscle activation in all directions in the 2-D space formed by the sagittal and frontal planes, but more in the sagittal than in the frontal plane, resulting in an accentuated “peanut shape.” This characterization of young healthy subjects’ ankle mechanical impedance with active muscles will serve as a baseline to investigate pathophysiological ankle behaviors of biomechanically and/or neurologically impaired patients. PMID:25203497

  20. Defense waste processing facility startup progress report

    SciTech Connect

    Iverson, D.C.; Elder, H.H.

    1992-01-01

    The Savannah River Site (SRS) has been operating a nuclear fuel cycle since the 1950's to produce nuclear materials in support of the national defense effort. About 83 million gallons of high level waste produced since operation began have been consolidated into 33 million gallons by evaporation at the waste tank farm. The Department of Energy has authorized the construction of the Defense Waste Processing Facility (DWPF) to immobilize the waste as a durable borosilicate glass contained in stainless steel canisters, prior to emplacement in a federal repository. The DWPF is now mechanically complete and undergoing commissioning and run-in activities. Cold startup testing using simulated non-radioactive feeds is scheduled to begin in November 1992 with radioactive operation scheduled to begin in May 1994. While technical issues have been identified which can potentially affect DWPF operation, they are not expected to negatively impact the start of non-radioactive startup testing.

  1. Defense waste processing facility startup progress report

    SciTech Connect

    Iverson, D.C.; Elder, H.H.

    1992-07-01

    The Savannah River Site (SRS) has been operating a nuclear fuel cycle since the 1950`s to produce nuclear materials in support of the national defense effort. About 83 million gallons of high level waste produced since operation began have been consolidated into 33 million gallons by evaporation at the waste tank farm. The Department of Energy has authorized the construction of the Defense Waste Processing Facility (DWPF) to immobilize the waste as a durable borosilicate glass contained in stainless steel canisters, prior to emplacement in a federal repository. The DWPF is now mechanically complete and undergoing commissioning and run-in activities. Cold startup testing using simulated non-radioactive feeds is scheduled to begin in November 1992 with radioactive operation scheduled to begin in May 1994. While technical issues have been identified which can potentially affect DWPF operation, they are not expected to negatively impact the start of non-radioactive startup testing.

  2. Differential MSC activation leads to distinct mononuclear leukocyte binding mechanisms

    NASA Astrophysics Data System (ADS)

    Kota, Daniel J.; Dicarlo, Bryan; Hetz, Robert A.; Smith, Philippa; Cox, Charles S.; Olson, Scott D.

    2014-04-01

    Advances in the field of Multipotent Mesenchymal Stromal cell (MSC) biology have demonstrated that MSCs can improve disease outcome when `activated' to exert immunomodulatory effects. However, the precise mechanisms modulating MSC-immune cells interactions remain largely elusive. In here, we activated MSC based on a recent polarization paradigm, in which MSCs can be polarized towards a pro- or anti-inflammatory phenotype depending on the Toll-like receptor stimulated, to dissect the mechanisms through which MSCs physically interact with and modulate leukocytes in this context. Our data show that MSCs activated through the Toll-like receptor (TLR) 4 pathway increased VCAM-1 and ICAM-1 dependent binding of leukocytes. On the other hand, TLR3 stimulation strongly increases leukocytes affinity to MSC comparatively, through the formation of cable-like hyaluronic acid structures. In addition, TLR4 activation elicited secretion of pro-inflammatory mediators by MSCs, whereas TLR3-activated MSCs displayed a milder pro-inflammatory phenotype, similar to inactivated MSCs. However, the differently activated MSCs maintained their ability to suppress leukocyte activation at similar levels in our in vitro model, and this immunomodulatory property was shown here to be partially mediated by prostaglandin. These results reinforce the concept that alternate activation profiles control MSC responses and may impact the therapeutic use of MSCs.

  3. Getting Defense Acquisition Right

    DTIC Science & Technology

    2017-01-01

    Buying Power 1.0 Figure 2. Better Buying Power 2.0 Figure 3. Better Buying Power 3.0 179 Figure 4. Contract Cost Growth on Highest Risk (Major...Crossing Critical Congressional Cost- Growth Thresholds iv Getting Defense Acquisition Right 67 96 97 184 Table 1. Root...Causes for Major Programs Crossing Critical Con­ gressional Cost- Growth Thresholds or Other Major Problems 185 Figure 8. Planned Length of Active

  4. Current Status of Proteomic Studies on Defense Responses in Rice.

    PubMed

    Chen, Xifeng; Bhadauria, Vijai; Ma, Bojun

    2016-01-01

    Biotic stresses are constraints to plant growth and development negatively impacting crop production. To counter such stresses, plants have developed stress-specific adaptations as well as simultaneous responses. The efficacy and magnitude of inducible adaptive responses are dependent on activation of signaling pathways and intracellular networks by modulating expression, or abundance, and/or post-translational modification of proteins associated with defense mechanisms. Proteomics plays an important role in elucidating plant defense mechanisms by mining the differential regulation of proteins to various biotic stresses. Rice, one of the most widely cultivated food crops in world, is constantly challenged by a variety of biotic stresses, and high-throughput proteomics approaches have been employed to unravel the molecular mechanism of the biotic stresses-response in rice. In this review, we summarize the latest advances of proteomic studies on defense responses and discuss the potential relevance of the proteins identified by proteomic means in rice defense mechanism. Furthermore, we provide perspective for proteomics in unraveling the molecular mechanism of rice immunity.

  5. Networks of WRKY transcription factors in defense signaling.

    PubMed

    Eulgem, Thomas; Somssich, Imre E

    2007-08-01

    Members of the complex family of WRKY transcription factors have been implicated in the regulation of transcriptional reprogramming associated with plant immune responses. Recently genetic evidence directly proving their significance as positive and negative regulators of disease resistance has accumulated. WRKY genes were shown to be functionally connected forming a transcriptional network composed of positive and negative feedback loops and feed-forward modules. Within a web of partially redundant elements some WRKY factors hold central positions mediating fast and efficient activation of defense programs. A key mechanism triggering strong immune responses appears to be based on the inactivation of defense-suppressing WRKY proteins.

  6. Platelet activation through a Bi-leaflet mechanical heart valve

    NASA Astrophysics Data System (ADS)

    Hedayat, Mohammadali; Borazjani, Iman

    2016-11-01

    Platelet activation is one of the major drawbacks of the Mechanical Heart Valves (MHVs) which can increase the risk of thrombus formation in patients. The platelet activation in MHVs can be due to the abnormal shear stress during the systole, the backward leakage flow during the diastole, and the flow through the hinge region. We investigate the contribution of each of the above mechanism to the activation of platelets in MHVs by performing simulations of the flow through the MHV and in the hinge region. The large scale heart valve simulations are performed in a straight aorta using a sharp interface curvilinear immersed boundary method along with a strong-coupling algorithm under physiological flow conditions. In addition, in order to perform the simulation of hinge region the flow field boundary conditions are obtained from the largescale simulations during a whole cardiac cycle. In order to investigate the role of hinge flow on platelet activation in MHVs, a 23mm St. Jude Medical Regent valve hinge with three different gap sizes is tested along with different platelet activation models to ensure the consistency of our results with different activation models. We compare the platelet activation of the hinge region against the bulk of the flow during one cardiac cycle. This work is supported by the American Heart Association Grant 13SDG17220022, and the computational resources were partly provided by Center for Computational Research (CCR) at University at Buffalo.

  7. Impact Ignition of Low Density Mechanically Activated and Multilayer Foil Ni/Al

    NASA Astrophysics Data System (ADS)

    Beason, Matthew; Mason, B.; Son, Steven; Groven, Lori

    2013-06-01

    Mechanical activation (MA) via milling of reactive materials provides a means of lowering the ignition threshold of shock initiated reactions. This treatment provides a finely mixed microstructure with wide variation in the resulting scales of the intraparticle microstructure that makes model validation difficult. In this work we consider nanofoils produced through vapor deposition with well defined periodicity and a similar degree of fine scale mixing. This allows experiments that may be easier to compare with computational models. To achieve this, both equimolar Ni/Al powder that has undergone MA using high energy ball milling and nanofoils milled into a powder using low energy ball milling were used. The Asay Shear impact experiment was conducted on both MA Ni/Al and Ni/Al nanofoil-based powders at low densities (<60%) to examine their impact response and reaction behavior. Scanning electron microscopy and energy-dispersive x-ray spectroscopy were used to verify the microstructure of the materials. The materials' mechanical properties were evaluated using nano-indentation. Onset temperatures were evaluated using differential thermal analysis/differential scanning calorimetry. Impact ignition thresholds, burning rates, temperature field, and ignition delays are reported. Funding from the Defense Threat Reduction Agency (DTRA) Grant Number HDTRA1-10-1-0119. Counter-WMD basic research program, Dr. Suhithi M. Peiris, program director is gratefully acknowledged.

  8. Platelet activation of mechanical versus bioprosthetic heart valves during systole.

    PubMed

    Hedayat, Mohammadali; Asgharzadeh, Hafez; Borazjani, Iman

    2017-03-11

    Thrombus formation is a major concern for recipients of mechanical heart valves (MHVs), which requires them to take anticoagulant drugs for the rest of their lives. Bioprosthetic heart valves (BHVs) do not require life-long anticoagulant therapy but deteriorate after 10-15years. The thrombus formation is initiated by the platelet activation which is thought to be mainly generated in MHVs by the flow through the hinge and the leakage flow during the diastole. However, our results show that the activation in the bulk flow during the systole phase might play an essential role as well. This is based on our results obtained by comparing the thrombogenic performance of a MHV and a BHV (as control) in terms of shear induced platelet activation under exactly the same conditions. Three different mathematical activation models including linear level of activation, damage accumulation, and Soares model are tested to quantify the platelet activation during systole using the previous simulations of the flow through MHV and BHV in a straight aorta under the same physiologic flow conditions. Results indicate that the platelet activation in the MHV at the beginning of the systole phase is slightly less than the BHV. However, at the end of the systole phase the platelet activation by the bulk flow for the MHV is several folds (1.41, 5.12, and 2.81 for linear level of activation, damage accumulation, and Soares model, respectively) higher than the BHV for all tested platelet activation models.

  9. Universal Hydrodynamic Mechanisms for Crystallization in Active Colloidal Suspensions

    NASA Astrophysics Data System (ADS)

    Singh, Rajesh; Adhikari, R.

    2016-11-01

    The lack of detailed balance in active colloidal suspensions allows dissipation to determine stationary states. Here we show that slow viscous flow produced by polar or apolar active colloids near plane walls mediates attractive hydrodynamic forces that drive crystallization. Hydrodynamically mediated torques tend to destabilize the crystal but stability can be regained through critical amounts of bottom heaviness or chiral activity. Numerical simulations show that crystallization is not nucleational, as in equilibrium, but is preceded by a spinodal-like instability. Harmonic excitations of the active crystal relax diffusively but the normal modes are distinct from an equilibrium colloidal crystal. The hydrodynamic mechanisms presented here are universal and rationalize recent experiments on the crystallization of active colloids.

  10. Structure and Mechanism of the Phosphotyrosyl Phosphatase Activator

    SciTech Connect

    Chao,Y.; Xing, Y.; Chen, Y.; Xu, Y.; Lin, Z.; Li, Z.; Jeffrey, P.; Stock, J.; Shi, Y.

    2006-01-01

    Phosphotyrosyl phosphatase activator (PTPA), also known as PP2A phosphatase activator, is a conserved protein from yeast to human. Here we report the 1.9 {angstrom} crystal structure of human PTPA, which reveals a previously unreported fold consisting of three subdomains: core, lid, and linker. Structural analysis uncovers a highly conserved surface patch, which borders the three subdomains, and an associated deep pocket located between the core and the linker subdomains. The conserved surface patch and the deep pocket are responsible for binding to PP2A and ATP, respectively. PTPA and PP2A A-C dimer together constitute a composite ATPase. PTPA binding to PP2A results in a dramatic alteration of substrate specificity, with enhanced phosphotyrosine phosphatase activity and decreased phosphoserine phosphatase activity. This function of PTPA strictly depends on the composite ATPase activity. These observations reveal significant insights into the function and mechanism of PTPA and have important ramifications for understanding PP2A function.

  11. Mechanisms underlying spontaneous patterned activity in developing neural circuits

    PubMed Central

    Blankenship, Aaron G.; Feller, Marla B.

    2010-01-01

    Patterned, spontaneous activity occurs in many developing neural circuits, including the retina, the cochlea, the spinal cord, the cerebellum and the hippocampus, where it provides signals that are important for the development of neurons and their connections. Despite differences in adult architecture and output across these various circuits, the patterns of spontaneous network activity and the mechanisms that generate it are remarkably similar and can include a depolarizing action of GABA, transient synaptic connections, extrasynaptic transmission, gap junction coupling and the presence of pacemaker-like neurons. Interestingly, spontaneous activity is robust; if one element of a circuit is disrupted another will generate similar activity. This research suggests that developing neural circuits exhibit transient and tunable features that maintain a source of correlated activity during critical stages of development. PMID:19953103

  12. A quantized mechanism for activation of pannexin channels

    PubMed Central

    Chiu, Yu-Hsin; Jin, Xueyao; Medina, Christopher B.; Leonhardt, Susan A.; Kiessling, Volker; Bennett, Brad C.; Shu, Shaofang; Tamm, Lukas K.; Yeager, Mark; Ravichandran, Kodi S.; Bayliss, Douglas A.

    2017-01-01

    Pannexin 1 (PANX1) subunits form oligomeric plasma membrane channels that mediate nucleotide release for purinergic signalling, which is involved in diverse physiological processes such as apoptosis, inflammation, blood pressure regulation, and cancer progression and metastasis. Here we explore the mechanistic basis for PANX1 activation by using wild type and engineered concatemeric channels. We find that PANX1 activation involves sequential stepwise sojourns through multiple discrete open states, each with unique channel gating and conductance properties that reflect contributions of the individual subunits of the hexamer. Progressive PANX1 channel opening is directly linked to permeation of ions and large molecules (ATP and fluorescent dyes) and occurs during both irreversible (caspase cleavage-mediated) and reversible (α1 adrenoceptor-mediated) forms of channel activation. This unique, quantized activation process enables fine tuning of PANX1 channel activity and may be a generalized regulatory mechanism for other related multimeric channels. PMID:28134257

  13. Insights into the Thiamine Diphosphate Enzyme Activation Mechanism: Computational Model for Transketolase Using a Quantum Mechanical/Molecular Mechanical Method.

    PubMed

    Nauton, Lionel; Hélaine, Virgil; Théry, Vincent; Hecquet, Laurence

    2016-04-12

    We propose the first computational model for transketolase (TK), a thiamine diphosphate (ThDP)-dependent enzyme, using a quantum mechanical/molecular mechanical method on the basis of crystallographic TK structures from yeast and Escherichia coli, together with experimental kinetic data reported in the literature with wild-type and mutant TK. This model allowed us to define a new route for ThDP activation in the enzyme environment. We evidenced a strong interaction between ThDP and Glu418B of the TK active site, itself stabilized by Glu162A. The crucial point highlighted here is that deprotonation of ThDP C2 is not performed by ThDP N4' as reported in the literature, but by His481B, involving a HOH688A molecule bridge. Thus, ThDP N4' is converted from an amino form to an iminium form, ensuring the stabilization of the C2 carbanion or carbene. Finally, ThDP activation proceeds via an intermolecular process and not by an intramolecular one as reported in the literature. More generally, this proposed ThDP activation mechanism can be applied to some other ThDP-dependent enzymes and used to define the entire TK mechanism with donor and acceptor substrates more accurately.

  14. Potential link between biotic defense activation and recalcitrance to induction of somatic embryogenesis in shoot primordia from adult trees of white spruce (Picea glauca)

    PubMed Central

    2013-01-01

    Background Among the many commercial opportunities afforded by somatic embryogenesis (SE), it is the ability to clonally propagate individual plants with rare or elite traits that has some of the most significant implications. This is particularly true for many long-lived species, such as conifers, but whose long generation times pose substantive challenges, including increased recalcitrance for SE as plants age. Identification of a clonal line of somatic embryo-derived trees whose shoot primordia have remained responsive to SE induction for over a decade, provided a unique opportunity to examine the molecular aspects underpinning SE within shoot tissues of adult white spruce trees. Results Microarray analysis was used to conduct transcriptome-wide expression profiling of shoot explants taken from this responsive genotype following one week of SE induction, which when compared with that of a nonresponsive genotype, led to the identification of four of the most differentially expressed genes within each genotype. Using absolute qPCR to expand the analysis to three weeks of induction revealed that differential expression of all eight candidate genes was maintained to the end of the induction treatment, albeit to differing degrees. Most striking was that both the magnitude and duration of candidate gene expression within the nonresponsive genotype was indicative of an intense physiological response. Examining their putative identities further revealed that all four encoded for proteins with similarity to angiosperm proteins known to play prominent roles in biotic defense, and that their high-level induction over an extended period is consistent with activation of a biotic defense response. In contrast, the more temperate response within the responsive genotype, including induction of a conifer-specific dehydrin, is more consistent with elicitation of an adaptive stress response. Conclusions While additional evidence is required to definitively establish an association

  15. Semi-dominant mutations in the CC-NB-LRR-type R gene, NLS1, lead to constitutive activation of defense responses in rice.

    PubMed

    Tang, Jiuyou; Zhu, Xudong; Wang, Yiqin; Liu, Linchuan; Xu, Bo; Li, Feng; Fang, Jun; Chu, Chengcai

    2011-06-01

    In this study, we characterized the semi-dominant mutant nls1-1D (necrotic leaf sheath 1) of rice, which displays spontaneous lesions, specifically on leaf sheaths, with a developmental pattern. nls1-1D plants also exhibited constitutively activated defense responses, including extensive cell death, excess hydrogen peroxide and salicylic acid (SA) accumulation, up-regulated expressions of pathogenesis-related genes, and enhanced resistance to bacterial pathogens. Map-based cloning revealed that NLS1 encodes a typical CC-NB-LRR-type protein in rice. The nls1-1D mutation causes a S367N substitution in the non-conserved region close to the GLPL motif of the NB domain. An adjacent S366T substitution was found in another semi-dominant mutant, nls1-2D, which exhibited the same phenotypes as nls1-1D. Combined analyses of wild-type plants transformed with the mutant NLS1 gene (nls1-1D), NLS1 RNAi and over-expression transgenic lines showed that nls1-2D is allelic to nls1-1D, and both mutations may cause constitutive auto-activation of the NLS1 R protein. Further real-time PCR analysis revealed that NLS1 is expressed constitutively in an age-dependent manner. In addition, because the morphology and constitutive defense responses of nls1-1D were not suppressed by blocking SA or NPR1 transcript accumulation, we suggest that NLS1 mediates both SA and NPR1-independent defense signaling pathways in rice.

  16. Defense-related proteins involved in sugarcane responses to biotic stress.

    PubMed

    Souza, Thais P; Dias, Renata O; Silva-Filho, Marcio C

    2017-02-20

    Sugarcane is one of the most important agricultural crops in the world. However, pathogen infection and herbivore attack cause constant losses in yield. Plants respond to pathogen infection by inducing the expression of several protein types, such as glucanases, chitinases, thaumatins, peptidase inhibitors, defensins, catalases and glycoproteins. Proteins induced by pathogenesis are directly or indirectly involved in plant defense, leading to pathogen death or inducing other plant defense responses. Several of these proteins are induced in sugarcane by different pathogens or insects and have antifungal or insecticidal activity. In this review, defense-related proteins in sugarcane are described, with their putative mechanisms of action, pathogen targets and biotechnological perspectives.

  17. Mechanism of activity and toxicity of Nystatin-Intralipid.

    PubMed

    Semis, Rita; Kagan, Sarah; Berdicevsky, Israela; Polacheck, Itzhack; Segal, Esther

    2013-05-01

    A novel lipid formulation of Nystatin (NYT), Nystatin-Intralipid (NYT-IL), which was found to be more active and less toxic in vitro and in vivo, was developed in our laboratory. The aim of the present study was to explore the possible mechanisms underlying its biological activity. To assess mechanisms affecting fungal cells we conducted the following experiments: killing kinetics, scanning and transmission electron microscopy (EM), measurements of potassium ion leakage and susceptibility in the presence of ergosterol. To study mechanisms affecting mammalian cells, we evaluated the effect of NYT-IL on a kidney cell line, with respect to viability, metabolic activity, potassium leakage and internalization of FITC-labeled human transferrin. NYT-IL exhibited killing kinetics patterns against Candida albicans similar to those of NYT and caused disruption of fungal cells and potassium ion leakage. Susceptibility tests showed that NYT-IL had lower antifungal activity in the presence of ergosterol. Thus, NYT-IL acts apparently by damaging fungal membrane, possibly through interaction with ergosterol, and maybe by additional modes of action. NYT-IL did not cause potassium leakage from mammalian kidney cells at any tested concentration and was not cytotoxic, whereas NYT, at high concentrations, led to K(+) leakage and was cytotoxic. Furthermore, the high NYT concentration interfered in the internalization process of human transferrin receptor (hTfnR) while NYT-IL did not. In summary, the Intralipid formulation of NYT diminishes the mechanisms responsible for toxicity to mammalian cells but preserves mechanisms of action against fungi, thereby suggesting superiority of NYT-IL as compared to NYT as an antifungal agent.

  18. Physical activity and cancer prevention: etiologic evidence and biological mechanisms.

    PubMed

    Friedenreich, Christine M; Orenstein, Marla R

    2002-11-01

    Scientific evidence is accumulating on physical activity as a means for the primary prevention of cancer. Nearly 170 observational epidemiologic studies of physical activity and cancer risk at a number of specific cancer sites have been conducted. The evidence for decreased risk with increased physical activity is classified as convincing for breast and colon cancers, probable for prostate cancer, possible for lung and endometrial cancers and insufficient for cancers at all other sites. Despite the large number of studies conducted on physical activity and cancer, most have been hampered by incomplete assessment of physical activity and a lack of full examination of effect modification and confounding. Several plausible hypothesized biological mechanisms exist for the association between physical activity and cancer, including changes in endogenous sexual and metabolic hormone levels and growth factors, decreased obesity and central adiposity and possibly changes in immune function. Weight control may play a particularly important role because links between excess weight and increased cancer risk have been established for several sites, and central adiposity has been particularly implicated in promoting metabolic conditions amenable to carcinogenesis. Based on existing evidence, some public health organizations have issued physical activity guidelines for cancer prevention, generally recommending at least 30 min of moderate-to-vigorous intensity physical activity on > or =5 d/wk. Although most research has focused on the efficacy of physical activity in cancer prevention, evidence is increasing that exercise also influences other aspects of the cancer experience, including cancer detection, coping, rehabilitation and survival after diagnosis.

  19. Mechanisms of spontaneous activity in developing spinal networks.

    PubMed

    O'Donovan, M J; Chub, N; Wenner, P

    1998-10-01

    Developing networks of the chick spinal cord become spontaneously active early in development and remain so until hatching. Experiments using an isolated preparation of the spinal cord have begun to reveal the mechanisms responsible for this activity. Whole-cell and optical recordings have shown that spinal neurons receive a rhythmic, depolarizing synaptic drive and experience rhythmic elevations of intracellular calcium during spontaneous episodes. Activity is expressed throughout the neuraxis and can be produced by different parts of the cord and by the isolated brain stem, suggesting that it does not depend upon the details of network architecture. Two factors appear to be particularly important for the production of endogenous activity. The first is the predominantly excitatory nature of developing synaptic connections, and the second is the presence of prolonged activity-dependent depression of network excitability. The interaction between high excitability and depression results in an equilibrium in which episodes are expressed periodically by the network. The mechanism of the rhythmic bursting within an episode is not understood, but it may be due to a "fast" form of network depression. Spontaneous embryonic activity has been shown to play a role in neuron and muscle development, but is probably not involved in the initial formation of connections between spinal neurons. It may be important in refining the initial connections, but this possibility remains to be explored.

  20. Class I Microcins: Their Structures, Activities, and Mechanisms of Resistance

    NASA Astrophysics Data System (ADS)

    Severinov, Konstantin; Semenova, Ekaterina; Kazakov, Teymur

    Microcin J25, microcin B17, and microcin C7-C51 are the three known members of class I posttranslationally modified microcins (heavily posttranslationally modified antibacterial peptides produced by Enterobacteriaceae with molecular weights of less than 5 kDa). The three microcins are unrelated to each other; they have structures that are highly atypical for ribosomally synthesized peptides and target essential molecular machines that are validated drug targets. In this chapter, available data on mechanisms of action, structure-activity relationships, and immunity mechanisms for class I microcins and related compounds are discussed.

  1. Avian host defense peptides.

    PubMed

    Cuperus, Tryntsje; Coorens, Maarten; van Dijk, Albert; Haagsman, Henk P

    2013-11-01

    Host defense peptides (HDPs) are important effector molecules of the innate immune system of vertebrates. These antimicrobial peptides are also present in invertebrates, plants and fungi. HDPs display broad-spectrum antimicrobial activities and fulfill an important role in the first line of defense of many organisms. It is becoming increasingly clear that in the animal kingdom the functions of HDPs are not confined to direct antimicrobial actions. Research in mammals has indicated that HDPs have many immunomodulatory functions and are also involved in other physiological processes ranging from development to wound healing. During the past five years our knowledge about avian HDPs has increased considerably. This review addresses our current knowledge on the evolution, regulation and biological functions of HDPs of birds.

  2. Microalloying of transition metal silicides by mechanical activation and field-activated reaction

    DOEpatents

    Munir, Zuhair A.; Woolman, Joseph N.; Petrovic, John J.

    2003-09-02

    Alloys of transition metal suicides that contain one or more alloying elements are fabricated by a two-stage process involving mechanical activation as the first stage and densification and field-activated reaction as the second stage. Mechanical activation, preferably performed by high-energy planetary milling, results in the incorporation of atoms of the alloying element(s) into the crystal lattice of the transition metal, while the densification and field-activated reaction, preferably performed by spark plasma sintering, result in the formation of the alloyed transition metal silicide. Among the many advantages of the process are its ability to accommodate materials that are incompatible in other alloying methods.

  3. Characterization of antimicrobial activity and mechanisms of low amphipathic peptides with different α-helical propensity.

    PubMed

    Zhu, Xin; Zhang, Licong; Wang, Jue; Ma, Zhi; Xu, Wei; Li, Jianping; Shan, Anshan

    2015-05-01

    Antimicrobial peptides (AMPs) serve as a defense mechanism within multicellular organisms and are attracting increasing attention because of their potential application in the treatment of multidrug-resistant infections. Amphipathicity has long been believed to be the most important consideration for the structural modification and design of both naturally occurring and synthetic AMPs. Previous studies indicated that disruptive amphipathicity formed by replacing the paired charged amino acid residues on the polar face of an amphipathic helix with tryptophan residues linked with hydrogen bonds on the basis of α-helical protein folding principles endowed the AMPs with increased cell selectivity. In an attempt to augment and hone this strategy further, we designed a series of imperfect amphipathic peptides by placing different types of amino acid residues at the hydrogen bond linked positions of α-helix structures to characterize their antimicrobial properties and mechanism of action. The d-Trp-substituted sequence (PRW4-d) showed greater antimicrobial potency than Cys-(C4), Asp-(D4), Ile-(I4), and Pro-(P4) substituted sequences, comparable to the l-Trp-substituted parent sequence (PRW4). Furthermore, the total replacement of Lys residues with Arg residues along the peptide sequence (PRW4-R) exhibited enhanced antimicrobial activity and cell selectivity. In addition, no cytotoxicity was observed among these synthetic peptides. PRW4-d and PRW4-R maintained their activities in the presence of physiological salts and human serum. The fluorescence spectroscopy, flow cytometry, and electron microscopy observations indicated that the optimized sequences exhibited excellent antimicrobial potency by inducing cytoplasmic membrane potential loss