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Sample records for activated chemical defense

  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. Activated chemical defense in marine sponges--a case study on Aplysinella rhax.

    PubMed

    Thoms, Carsten; Schupp, Peter J

    2008-09-01

    Activated chemical defense, i.e., the rapid conversion of precursor molecules to defensive compounds following tissue damage, has been well documented for terrestrial and marine plants; but evidence for its presence in sessile marine invertebrates remains scarce. We observed a wound-activated conversion of psammaplin A sulfate to psammaplin A in tissue of the tropical sponge Aplysinella rhax. The conversion is rapid (requiring only seconds), the turnover rate increases with increasing wounding activity (e.g., approximately 20% after tissue stabbing vs. approximately 85% after tissue grinding), and is likely enzyme-catalyzed (no reaction in the absence of water and inhibition of the conversion by heat). Fish feeding assays with the pufferfish Canthigaster solandri, an omnivorous sponge predator, revealed an increased anti-feeding activity by the conversion product psammaplin A compared to the precursor psammaplin A sulfate. We propose that the wound-activated formation of psammaplin A in A. rhax is an activated defense targeted against predator species that are not efficiently repelled by the sponge's constitutive chemical defense. Recent observations of conversion reactions also in other sponge species indicate that more activated defenses may exist in this phylum. Based on the findings of this study, we address the question whether activated defenses may be more common in sponges--and perhaps also in other sessile marine invertebrates--than hitherto believed.

  3. The neuroecology of chemical defenses.

    PubMed

    Derby, Charles D; Aggio, Juan F

    2011-11-01

    Chemicals are a frequent means whereby organisms defend themselves against predators, competitors, parasites, microbes, and other potentially harmful organisms. Much progress has been made in understanding how a phylogenetic diversity of organisms living in a variety of environments uses chemical defenses. Chief among these advances is determining the molecular identity of defensive chemicals and the roles they play in shaping interactions between individuals. Some progress has been made in deciphering the molecular, cellular, and systems level mechanisms underlying these interactions, as well as how these interactions can lead to structuring of communities and even ecosystems. The neuroecological approach unifies practices and principles from these diverse disciplines and at all scales as it attempts to explain in a single conceptual framework the abundances of organisms and the distributions of species within natural habitats. This article explores the neuroecology of chemical defenses with a focus on aquatic organisms and environments. We review the concept of molecules of keystone significance, including examples of how saxitoxin and tetrodotoxin can shape the organization and dynamics of marine and riparian communities, respectively. We also describe the current status and future directions of a topic of interest to our research group-the use of ink by marine molluscs, especially sea hares, in their defense. We describe a diversity of molecules and mechanisms mediating the protective effects of sea hares' ink, including use as chemical defenses against predators and as alarm cues toward conspecifics, and postulate that some defensive molecules may function as molecules of keystone significance. Finally, we propose future directions for studying the neuroecology of the chemical defenses of sea hares and their molluscan relatives, the cephalopods.

  4. 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

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

    PubMed

    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.

  6. Chemical defense lowers plant competitiveness.

    PubMed

    Ballhorn, Daniel J; Godschalx, Adrienne L; Smart, Savannah M; Kautz, Stefanie; Schädler, Martin

    2014-11-01

    Both plant competition and plant defense affect biodiversity and food web dynamics and are central themes in ecology research. The evolutionary pressures determining plant allocation toward defense or competition are not well understood. According to the growth-differentiation balance hypothesis (GDB), the relative importance of herbivory and competition have led to the evolution of plant allocation patterns, with herbivore pressure leading to increased differentiated tissues (defensive traits), and competition pressure leading to resource investment towards cellular division and elongation (growth-related traits). Here, we tested the GDB hypothesis by assessing the competitive response of lima bean (Phaseolus lunatus) plants with quantitatively different levels of cyanogenesis-a constitutive direct, nitrogen-based defense against herbivores. We used high (HC) and low cyanogenic (LC) genotypes in different competition treatments (intra-genotypic, inter-genotypic, interspecific), and in the presence or absence of insect herbivores (Mexican bean beetle, Epilachna varivestis) to quantify vegetative and generative plant parameters (above and belowground biomass as well as seed production). Highly defended HC-plants had significantly lower aboveground biomass and seed production than LC-plants when grown in the absence of herbivores implying significant intrinsic costs of plant cyanogenesis. However, the reduced performance of HC- compared to LC-plants was mitigated in the presence of herbivores. The two plant genotypes exhibited fundamentally different responses to various stresses (competition, herbivory). Our study supports the GDB hypothesis by demonstrating that competition and herbivory affect different plant genotypes differentially and contributes to understanding the causes of variation in defense within a single plant species.

  7. Palatability of macroalgae that use different types of chemical defenses.

    PubMed

    Erickson, Amy A; Paul, Valerie J; Van Alstyne, Kathryn L; Kwiatkowski, Lisa M

    2006-09-01

    This study compared algal palatability and chemical defenses from subtropical green algae that may use different types of defense systems that deter feeding by the rock-boring sea urchin Echinometra lucunter. The potential defense systems present include (1) the terpenoid caulerpenyne and its activated products from Caulerpa spp., and (2) dimethylsulfoniopropionate (DMSP)-related defenses in Ulva spp. Secondary metabolites from these chemical groups have been shown to deter feeding by various marine herbivores, including tropical and temperate sea urchins. Live algal multiple-choice feeding assays and assays incorporating algal extracts or isolated metabolites into an artificial diet were conducted. Several green algae, including Ulva lactuca, Caulerpa prolifera, and Cladophora sp., were unpalatable. Nonpolar extracts from U. lactuca deterred feeding, whereas nonpolar extracts from C. prolifera had no effect on feeding. Polar extracts from both species stimulated feeding. Caulerpenyne deterred feeding at approximately 4% dry mass; however, dimethyl sulfide and acrylic acid had no effect at natural and elevated concentrations. E. lucunter is more tolerant than other sea urchins to DMSP-related defenses and less tolerant to caulerpenyne than many reef fish. Understanding the chemical defenses of the algae tested in this study is important because they, and related species, frequently are invasive or form blooms, and can significantly modify marine ecosystems. PMID:16906362

  8. Water-borne cues induce chemical defense in a marine alga (Ascophyllum nodosum).

    PubMed

    Toth, G B; Pavia, H

    2000-12-19

    It is well known that herbivores can induce chemical defenses in terrestrial vascular plants, but few examples of inducible production of defense chemicals have been reported for aquatic macrophytes. Furthermore, it is well established that water-borne chemical cues from predators or predator-wounded conspecifics can induce defensive changes of aquatic prey animals, but no such communication between aquatic herbivores and seaweeds has been reported. Here we show that water-borne cues from actively feeding herbivorous gastropods, flat periwinkles (Littorina obtusata), can serve as external signals to induce production of defense chemicals (phlorotannins) in unharmed individuals of seaweeds, knotted wrack (Ascophyllum nodosum), and that the increased levels of defense chemicals deter further feeding by periwinkles. Because seaweeds have poorly developed internal-transport systems and may not be able to elicit systemic-induced chemical defenses through conveyance of internal signals, this mechanism ensures that seaweeds can anticipate future periwinkle attacks without receiving direct damage by herbivores. PMID:11106371

  9. Water-borne cues induce chemical defense in a marine alga (Ascophyllum nodosum)

    PubMed Central

    Toth, Gunilla B.; Pavia, Henrik

    2000-01-01

    It is well known that herbivores can induce chemical defenses in terrestrial vascular plants, but few examples of inducible production of defense chemicals have been reported for aquatic macrophytes. Furthermore, it is well established that water-borne chemical cues from predators or predator-wounded conspecifics can induce defensive changes of aquatic prey animals, but no such communication between aquatic herbivores and seaweeds has been reported. Here we show that water-borne cues from actively feeding herbivorous gastropods, flat periwinkles (Littorina obtusata), can serve as external signals to induce production of defense chemicals (phlorotannins) in unharmed individuals of seaweeds, knotted wrack (Ascophyllum nodosum), and that the increased levels of defense chemicals deter further feeding by periwinkles. Because seaweeds have poorly developed internal-transport systems and may not be able to elicit systemic-induced chemical defenses through conveyance of internal signals, this mechanism ensures that seaweeds can anticipate future periwinkle attacks without receiving direct damage by herbivores. PMID:11106371

  10. The chemical defense in larvae of the earwig Forficula auricularia.

    PubMed

    Gasch, Tina; Vilcinskas, Andreas

    2014-08-01

    Larvae of the European earwig, Forficula auricularia, possess a paired pygidial gland with yet unknown content and function. We used gas chromatography-mass spectrometry to analyze the larval secretions revealing the presence of 2-methyl-1,4-benzoquinone, 2-ethyl-1,4-benzoquinone, n-tridecane and n-pentadecane. Based on our recent discovery that the morphologically-distinct abdominal glands of adult earwigs produce secretions with antibacterial, antifungal and nematicidal activity, we propose that the pygidial glands mediate chemical defenses in the larvae. We next considered whether the defensive functions of larval secretions include repellent activity against sympatric predators. Therefore, we tested the effects of larval secretions on foraging workers of the ant species Myrmica rubra, the actively hunting spiders Anyphaena accentuata and Philodromus aureolus and the net-hunting spider Pholcus phalangioides in laboratory feeding assays. The secretion is released in response to ant attacks, and discourages feeding in M. rubra, however, it does not discourage feeding in spiders. Our results suggest that earwigs use different glands during ontogenesis to produce secretions that play roles in chemical defense against predators such as ants.

  11. Physics of a ballistic missile defense - The chemical laser boost-phase defense

    NASA Technical Reports Server (NTRS)

    Grabbe, Crockett L.

    1988-01-01

    The basic physics involved in proposals to use a chemical laser based on satellites for a boost-phase defense are investigated. After a brief consideration of simple physical conditions for the defense, a calculation of an equation for the number of satellites needed for the defense is made along with some typical values of this for possible future conditions for the defense. Basic energy and power requirements for the defense are determined. A sumary is made of probable minimum conditions that must be achieved for laser power, targeting accuracy, number of satellites, and total sources for power needed.

  12. 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…

  13. Medical defense against blistering chemical warfare agents.

    PubMed

    Smith, W J; Dunn, M A

    1991-08-01

    First used in World War I, chemical blistering agents present a serious medical threat that has stimulated renewed interest in the light of extensive use in recent conflicts. Current medical management cannot yet prevent or minimize injury from the principal agent of concern--sulfur mustard. Research directed at this goal depends on defining effective intervention in the metabolic alterations induced by exposure to sulfur mustard.

  14. Winter chemical defense of Alaskan balsam poplar against snowshoe hares.

    PubMed

    Reichardt, P B; Bryant, J P; Mattes, B R; Clausen, T P; Chapin, F S; Meyer, M

    1990-06-01

    Palatabilities of parts and growth stages of balsam poplar (Populus balsamifera) to snowshoe hares (Lepus americanus) are related to concentrations of specific plant metabolites that act as antifeedants. Buds are defended from hares by cineol, benzyl alcohol, and (+)-α-bisabolol. Internodes are defended by 6-hydroxycylohexenone (6-HCH) and salicaldehyde. Although defense of interaodes depends upon both compounds, the defense of juvenile internodes is principally related to salicaldehyde concentration; the defense of internode current annual growth is principally related to 6-HCH concentration. The concentration of 6-HCH can be supplemented by the hydrolysis of phenol glycosides when plant tissue is disrupted, raising the possibility of a dynamic element of the chemical defense of poplar.

  15. Egg Production Constrains Chemical Defenses in a Neotropical Arachnid

    PubMed Central

    Nazareth, Taís M.; Machado, Glauco

    2015-01-01

    Female investment in large eggs increases the demand for fatty acids, which are allocated for yolk production. Since the biosynthetic pathway leading to fatty acids uses the same precursors used in the formation of polyketides, allocation trade-offs are expected to emerge. Therefore, egg production should constrain the investment in chemical defenses based on polyketides, such as benzoquinones. We tested this hypothesis using the harvestman Acutiosoma longipes, which produces large eggs and releases benzoquinones as chemical defense. We predicted that the amount of secretion released by ovigerous females (OFs) would be smaller than that of non-ovigerous females (NOF). We also conducted a series of bioassays in the field and in the laboratory to test whether egg production renders OFs more vulnerable to predation. OFs produce less secretion than NOFs, which is congruent with the hypothesis that egg production constrains the investment in chemical defenses. Results of the bioassays show that the secretion released by OFs is less effective in deterring potential predators (ants and spiders) than the secretion released by NOFs. In conclusion, females allocate resources to chemical defenses in a way that preserves a primary biological function related to reproduction. However, the trade-off between egg and secretion production makes OFs vulnerable to predators. We suggest that egg production is a critical moment in the life of harvestman females, representing perhaps the highest cost of reproduction in the group. PMID:26331946

  16. Space-Based Chemical Lasers in strategic defense

    SciTech Connect

    Wildt, D. )

    1992-07-01

    The Strategic Defense Initiative Organization (SDIO) has made significant progress in developing Space-Based chemical Laser (SBL) technologies and in studying the SBLs global defense capability. In this mission, a constellation of several orbiting laser platforms provides continuous global defense by intercepting threatening missiles in their boost phase, including short range ballistic missiles (SRBMs). An optional smaller constellation provides defense against launches from the low and midlatitude regions. In addition, SBLs have utility in other important related missions such as surveillance, air defense and discrimination. The hardware necessary to build such a system has been developed to the point where it is mature and ready for demonstration in space. Advances have been made in each of the following major areas of the SBL: laser device; optics/beam control; beam pointing; ATP (acquisition, tracking and pointing); uncooled optics; and laser lethality. Integration of the key laser and beam control technologies is now occurring in the ground-based ALI experiment, and a space demonstration experiment, Star LITE, is in the planning and concept development phase.

  17. Biogeography of sponge chemical ecology: comparisons of tropical and temperate defenses.

    PubMed

    Becerro, Mikel A; Thacker, Robert W; Turon, Xavier; Uriz, Maria J; Paul, Valerie J

    2003-03-01

    Examples from both marine and terrestrial systems have supported the hypothesis that predation is higher in tropical than in temperate habitats and that, as a consequence, tropical species have evolved more effective defenses to deter predators. Although this hypothesis was first proposed for marine sponges over 25 years ago, our study provides the first experimental test of latitudinal differences in the effectiveness of sponge chemical defenses. We collected 20 common sponge species belonging to 14 genera from tropical Guam and temperate Northeast Spanish coasts (Indo-Pacific and Mediterranean biogeographic areas) and conducted field-based feeding experiments with large and small fish predators in both geographic areas. We use the term global deterrence to describe the deterrent activity of a sponge extract against all of the predators used in our experiments and to test the hypothesis that sponges from Guam are chemically better defended than their Mediterranean counterparts. Sympatric and allopatric deterrence refer to the average deterrent activity of a sponge against sympatric or allopatric predators. All of the sponges investigated in this study showed deterrent properties against some predators. However, 35% of the sponge species were deterrent in at least one but not in all the experiments, supporting the idea that predators can respond to chemical defenses in a species-specific manner. Tropical and temperate sponges have comparable global, sympatric, and allopatric deterrence, suggesting not only that chemical defenses from tropical and temperate sponges are equally strong but also that they are equally effective against sympatric and allopatric predators. Rather than supporting geographic trends in the production of chemical defenses, our data suggest a recurrent selection for chemical defenses in sponges as a general life-history strategy.

  18. Marine biofilm bacteria evade eukaryotic predation by targeted chemical defense.

    PubMed

    Matz, Carsten; Webb, Jeremy S; Schupp, Peter J; Phang, Shui Yen; Penesyan, Anahit; Egan, Suhelen; Steinberg, Peter; Kjelleberg, Staffan

    2008-07-23

    Many plants and animals are defended from predation or herbivory by inhibitory secondary metabolites, which in the marine environment are very common among sessile organisms. Among bacteria, where there is the greatest metabolic potential, little is known about chemical defenses against bacterivorous consumers. An emerging hypothesis is that sessile bacterial communities organized as biofilms serve as bacterial refuge from predation. By testing growth and survival of two common bacterivorous nanoflagellates, we find evidence that chemically mediated resistance against protozoan predators is common among biofilm populations in a diverse set of marine bacteria. Using bioassay-guided chemical and genetic analysis, we identified one of the most effective antiprotozoal compounds as violacein, an alkaloid that we demonstrate is produced predominately within biofilm cells. Nanomolar concentrations of violacein inhibit protozoan feeding by inducing a conserved eukaryotic cell death program. Such biofilm-specific chemical defenses could contribute to the successful persistence of biofilm bacteria in various environments and provide the ecological and evolutionary context for a number of eukaryote-targeting bacterial metabolites.

  19. Assistant to the secretary of defense for nuclear and chemical and biological defense programs (ATSD(NCB)). Change 1

    SciTech Connect

    Kennedy, R.

    1996-03-01

    This Change 1 to DoD Directive 5134.8, dated June 8, 1994, is provided to DTIC. NOTE: In accordance with Section 904 of the DoD Authorization Act for FY 1996 (P.L. 104-106), this change redesignates the Assistant to the Secretary of Defense for Atomic Energy (ATSD(AE)) as the Assistant to the Secretary of Defense for Nuclear and Chemical and Biological Defense Programs (ATSD(NCB)).

  20. Chemical-biological defense remote sensing: what's happening

    NASA Astrophysics Data System (ADS)

    Carrico, John P.

    1998-08-01

    The proliferation of weapons of mass destruction (WMD) continues to be a serious threat to the security of the US. Proliferation of chemical and biological (CB) weapons is particularly disturbing, and the threats posed can be devastating. Critical elements of the US efforts to reduce and counter WMD proliferation include: (1) the location and characterization of WMD facilities and capabilities worldwide; (2) the ability to rapidly detect and identify the use of CB weapons for expeditious warning and reporting on the battlefield; and (3) the capability to mitigate deleterious consequences of a CB incident through effective protective and medical treatment measures. Remote sensing has been touted as a key technology in these efforts. Historically, the role of remote sensing in CB defense has been to provide early warning of an attack from an extended distance. However, additional roles for remote sensing in CB defense, as well as applications in related missions, are possible and should be pursued. This paper examines what has been happening in remote sensing over the past decade to address needs in this area. Accomplishments, emerging technologies, programmatic issues, and opportunities for the future are covered. The Department of Defence chemical- biological, the Department of Energy's Chemical Analysis by Laser Interrogation of Proliferation Effluents, and other agency related programs are examined. Also, the status of remote sensing in the commercial market arena for environmental monitoring, its relevance to the WMD counterproliferation program, and opportunities for technology transfer are discussed. A course of action for the future is recommended.

  1. Nine-size system for chemical defense gloves. Technical report

    SciTech Connect

    Robinette, K.M.; Annis, J.F.

    1986-07-01

    The purpose of this effort was to meet the need for improved sizing of chemical defense gloves for Air Force men and women. A nine-size system was developed from available hand data. The development process and size values are presented in this report. Some summary statistics and regression equations are provided to aid investigators who may wish to make modifications. Although the anthropometric sizing system outlined in this report is statistically sound, it is experimental. The authors recommend that anthropometric fit-testing be conducted prior to full-scale glove production.

  2. Proposal of a defense application for a chemical oxygen laser

    NASA Astrophysics Data System (ADS)

    Takehisa, K.

    2015-05-01

    Defense application for a chemical oxygen laser (COL) is explained. Although a COL has not yet been successful in lasing, the oscillator was estimated to produce a giant pulse with the full width at half maximum (FWHM) of ~0.05ms which makes the damage threshold for the mirrors several-order higher than that for a typical solid-state laser with a ~10ns pulse width. Therefore it has a potential to produce MJ class output considering the simple scalability of being a chemical laser. Since within 0.05ms a supersonic aircraft can move only a few centimeters which is roughly equal to the spot size of the focused beam at ~10km away using a large-diameter focusing mirror, a COL has a potential to make a damage to an enemy aircraft by a single shot without beam tracking. But since the extracted beam can propagate up to a few kilometers due to the absorption in the air, it may be suitable to use in space. While a chemical oxygen-iodine laser (COIL) can give a pulsed output with a width of ~2 ms using a high-pressure singlet oxygen generator (SOG). Therefore a pulsed COIL may also not require beam tracking if a target aircraft is approaching. Another advantage for these pulsed high-energy lasers (HELs) is that, in case of propagating in cloud or fog, much less energy is required for a laser for aerosol vaporization (LAV) than that of a LAV for a CW HEL. Considerations to use a COL as a directed energy weapon (DEW) in a point defense system are shown.

  3. Allocation of chemical and structural defenses in the sponge Melophlus sarasinorum

    PubMed Central

    Rohde, Sven; Schupp, Peter J.

    2011-01-01

    Sponges have evolved a variety of chemical and structural defense mechanisms to avoid predation. While chemical defense is well established in sponges, studies on structural defense are rare and with ambiguous results. We used field and laboratory experiments to investigate predation patterns and the anti-predatory defense mechanisms of the sponge Melophlus sarasinorum, a common inhabitant of Indo-pacific coral reefs. Specifically, we aimed to investigate whether M. sarasinorum is chemically or structurally defended against predation and if the defenses are expressed differently in the ectosomal and choanosomal tissue of the sponge. Chemical defense was measured as feeding deterrence, structural defense as feeding deterrence and toughness. Our results demonstrated that chemical defense is evenly distributed throughout the sponge and works in conjunction with a structurally defended ectosome to further reduce predation levels. The choanosome of the sponge contained higher protein levels, but revealed no structural defense. We conclude that the equal distribution of chemical defenses throughout M. sarasinorum is in accordance with Optimal Defense Theory (ODT) in regards to fish predation, while structural defense supports ODT by being restricted to the surface layer which experiences the highest predation risks from mesograzers. PMID:21461028

  4. Allocation of chemical and structural defenses in the sponge Melophlus sarasinorum.

    PubMed

    Rohde, Sven; Schupp, Peter J

    2011-03-15

    Sponges have evolved a variety of chemical and structural defense mechanisms to avoid predation. While chemical defense is well established in sponges, studies on structural defense are rare and with ambiguous results. We used field and laboratory experiments to investigate predation patterns and the anti-predatory defense mechanisms of the sponge Melophlus sarasinorum, a common inhabitant of Indo-pacific coral reefs. Specifically, we aimed to investigate whether M. sarasinorum is chemically or structurally defended against predation and if the defenses are expressed differently in the ectosomal and choanosomal tissue of the sponge. Chemical defense was measured as feeding deterrence, structural defense as feeding deterrence and toughness. Our results demonstrated that chemical defense is evenly distributed throughout the sponge and works in conjunction with a structurally defended ectosome to further reduce predation levels. The choanosome of the sponge contained higher protein levels, but revealed no structural defense. We conclude that the equal distribution of chemical defenses throughout M. sarasinorum is in accordance with Optimal Defense Theory (ODT) in regards to fish predation, while structural defense supports ODT by being restricted to the surface layer which experiences the highest predation risks from mesograzers.

  5. Department of Defense FY 1990/FY 1991 biennial budget estimates submitted to Congress January 1989. Chemical Agents and Munitions Destruction Defense

    SciTech Connect

    Not Available

    1989-01-01

    The Chemical Demilitarization Program was established in response to Section 1412 of the 1986 Defense Authorization Act (Public Law 99-145) that directs the DOD to destroy the complete unitary chemical stockpile by 1994 in conjunction with the production of binary chemical weapons. The Fiscal Year 1989 Defense Authorization Act (Public Law 100-456) extended program completion to 1997. Estimates contained in this budget reflect the 1997 completion date. The Chemical Agents and Munitions Destruction Defense appropriation includes operations and maintenance, procurement, and research and development budget activities. Construction funds in support of chemical demilitarization are contained in the Military Construction, Army Budget request. The Chemical Demilitarization Program provides resources to develop and test monitoring and disposal technology; equip, operate, and maintain disposal facilities; provide safe and secure transportation of chemical agents and munitions for disposal; dispose of all waste products; and decontaminate and dismantle all disposal equipment at the conclusion of toxic operations. Chemical agents and munitions are stored within the continental United States, Johnston Atoll, and the Federal Republic of Germany. Funds within this appropriation will by used to destroy the entire unitary lethal chemical stockpile. Also included are funds for Emergency Response and Program Oversight.

  6. Dexterity testing of chemical-defense gloves. Technical report

    SciTech Connect

    Robinette, K.M.; Ervin; Zehner, G.F.

    1986-05-01

    Chemical-defense gloves (12.5-mil Epichlorohydron/Butyl, 14-mil Epichlorohydron/Butyl, and 7-mil Butyl with Nomex overgloves) were subjected to four dexterity tests (O'Connor Finger Dexterity Test, Pennsylvania Bi-Manual Worksample-Assembly, Minnesota Rate of Manipulation Turning, and the Crawford Small Test). Results indicated that subjects performances were most impaired by the 7-mil Butyl with Nomex overglove. Though differences between the other three gloved conditions were not always statistically significant, subjects performed silghtly better while wearing the Epichlorohydron/Butyl gloves, no matter which thickness, than they did while wearing the 15-mil butyl gloves. High negative correlation between anthropometry and gloved tests scores of subjects suggested that poor glove fit may also have affected subjects performances.

  7. Chemical defenses promote persistence of the aquatic plant Micranthemum umbrosum.

    PubMed

    Parker, John D; Collins, Dwight O; Kubanek, Julia; Sullards, M Cameron; Bostwick, David; Hay, Mark E

    2006-04-01

    Five of the most common macrophytes from an aquaculture facility with high densities of the herbivorous Asian grass carp (Ctenopharyngodon idella) were commonly unpalatable to three generalist consumers-grass carp and the native North American crayfishes Procambarus spiculifer and P. acutus. The rooted vascular plant Micranthemum umbrosum comprised 89% of the total aboveground plant biomass and was unpalatable to all three consumers as fresh tissues, as homogenized pellets, and as crude extracts. Bioassay-guided fractionation of the crude extract from M. umbrosum led to four previously known compounds that each deterred feeding by at least one consumer: 3,4,5-trimethoxyallylbenzene (1) and three lignoids: beta-apopicropodophyllin (2); (-)-(3S,4R,6S)-3-(3',4'-methylenedioxy-alpha-hydroxybenzyl)-4-(3'',4''-dimethoxybenzyl)butyrolactone (3); and (-)-hibalactone (4). None of the remaining four macrophytes produced a chemically deterrent extract. A 16-mo manipulative experiment showed that the aboveground biomass of M. umbrosum was unchanged when consumers were absent, but the biomass of Ludwigia repens, a plant that grass carp preferentially consumed over M. umbrosum, increased over 300-fold. Thus, selective feeding by grass carp effectively eliminates most palatable plants from this community and promotes the persistence of the chemically defended M. umbrosum, suggesting that plant defenses play critical yet understudied roles in the structure of freshwater plant communities.

  8. Chemical defense of a rove beetle (Creophilus maxillosus).

    PubMed

    Jefson, M; Meinwald, J; Nowicki, S; Hicks, K; Eisner, T

    1983-01-01

    The abdominal defensive glands ofC. maxillosus secrete a mixture (70μg/beetle) of isoamyl alcohol (I), isoamyl acetate (II), iridodial (III), actinidine (IV), dihydronepetalactone (VE), and (E)-8-oxocitronellyl acetate (X). When disturbed, the beetle everts the glands and revolves the abdomen so as to wipe the glands against the offending agent. Fecal fluid is commonly emitted at the same time and may become added to the glandular material. Ants (Formica exsectoides) are effectively fended off by the beetle and were shown in bioassays (Monomorium destructor) to be repelled by the four major components of the secretion (II, III, X, VE); the principal component (VE) was the most active. Some anatomical features of the glands are described.

  9. 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…

  10. 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...

  11. Miniature mass spectrometer for chemical sensing in homeland defense applications

    NASA Astrophysics Data System (ADS)

    Sinha, Mahadeva P.; Houseman, John

    2003-07-01

    A Miniature Mass Spectrometer (MMS) with an array detector has been developed at the Jet Propulsion Laboratory (JPL). The spectrometer has a focal plane geometry, and an array detector that can measure the intensities of different masses simultaneously after their separation along the focal plane. In the past, the large mass, size and the lack of an array detector with high gain (such as an electron multiplier) did not allow the application of focal plane mass spectrometer to the measurement that required high sensitivity and portability. In the JPL developed-MMS, miniaturization has been accomplished by using rare earth magnet material and novelties in the design of the magnetic and electric sectors. A new ion detector was developed for the measurement of the intensities of different mass ions. The array detector is based on the conversion sequence of ions into electrons into photons and their final measurement by a photon array detector. MMS possesses high sensitivity, specificity, and fast response time and can be used as a universal chemical analyzer. It will find application in a variety of Home Defense tasks. MMS is presently being applied for the detection of propellants (hydrazine and its derivatives). The instrument will have a mass of 1-2 kg and consume a power of 2-4 W for operation

  12. No evidence for the induction of brown algal chemical defense by the phytohormones jasmonic acid and methyl jasmonate.

    PubMed

    Wiesemeier, Theresa; Jahn, Karsten; Pohnert, Georg

    2008-12-01

    Induced chemical defense reactions are widespread in marine brown algae. Despite the evidence that the biosynthesis of defense metabolites can be up-regulated upon herbivory, we do not know how this regulation of biosynthetic pathways to secondary metabolites is achieved in brown algae. In higher plants, the phytohormone jasmonic acid (JA) is crucial for the mediation of induced chemical defenses, and several findings of this metabolite from marine sources have been reported. We tested the hypothesis that JA or related metabolites play a role in induced brown algal defense. Quantification of oxylipins with a detection limit around 20 ng g(-1) algal tissue did not reveal the presence of JA in the seven examined brown algal species Dictyota dichotoma, Colpomenia peregrina, Ectocarpus fasciculatus, Fucus vesiculosus, Himanthalia elongata, Saccharina latissima (formerly Laminaria saccharina), and Sargassum muticum. Moreover, treatment with ecologically relevant concentrations of JA and methyl jasmonate did not lead to a significant change in the profile of medium- and non-polar metabolites of the tested algae. Only when high concentrations of > or =500 microg ml(-1) medium of the phytohormones were applied that a metabolic response which could be attributed to unspecific stress was observed. Bioassays with D. dichotoma that focused on medium- and non-polar compounds confirmed the lack of a biological role of JA and methyl jasmonate in the induction of algal induced chemical defenses. The phytohormone-treated samples did not exhibit any increased defense potential towards the amphipod Ampithoe longimana and the isopod Paracerceis caudata. JA and related phytohormones, known to be active in higher plants, thus appear to play no role in brown algae for induction of the defense chemicals studied here. PMID:19020937

  13. No evidence for the induction of brown algal chemical defense by the phytohormones jasmonic acid and methyl jasmonate.

    PubMed

    Wiesemeier, Theresa; Jahn, Karsten; Pohnert, Georg

    2008-12-01

    Induced chemical defense reactions are widespread in marine brown algae. Despite the evidence that the biosynthesis of defense metabolites can be up-regulated upon herbivory, we do not know how this regulation of biosynthetic pathways to secondary metabolites is achieved in brown algae. In higher plants, the phytohormone jasmonic acid (JA) is crucial for the mediation of induced chemical defenses, and several findings of this metabolite from marine sources have been reported. We tested the hypothesis that JA or related metabolites play a role in induced brown algal defense. Quantification of oxylipins with a detection limit around 20 ng g(-1) algal tissue did not reveal the presence of JA in the seven examined brown algal species Dictyota dichotoma, Colpomenia peregrina, Ectocarpus fasciculatus, Fucus vesiculosus, Himanthalia elongata, Saccharina latissima (formerly Laminaria saccharina), and Sargassum muticum. Moreover, treatment with ecologically relevant concentrations of JA and methyl jasmonate did not lead to a significant change in the profile of medium- and non-polar metabolites of the tested algae. Only when high concentrations of > or =500 microg ml(-1) medium of the phytohormones were applied that a metabolic response which could be attributed to unspecific stress was observed. Bioassays with D. dichotoma that focused on medium- and non-polar compounds confirmed the lack of a biological role of JA and methyl jasmonate in the induction of algal induced chemical defenses. The phytohormone-treated samples did not exhibit any increased defense potential towards the amphipod Ampithoe longimana and the isopod Paracerceis caudata. JA and related phytohormones, known to be active in higher plants, thus appear to play no role in brown algae for induction of the defense chemicals studied here.

  14. Stereoselective chemical defense in the Drosophila parasitoid Leptopilina heterotoma is mediated by (-)-iridomyrmecin and (+)-isoiridomyrmecin.

    PubMed

    Stökl, Johannes; Hofferberth, John; Pritschet, Maria; Brummer, Michael; Ruther, Joachim

    2012-04-01

    Chemical defense mechanisms are widespread among insects but have rarely been demonstrated in parasitoid wasps. Here, we show that the Drosophila parasitoid Leptopilina heterotoma (Hymenoptera, Figitidae) produces (-)-iridomyrmecin and (+)-isoiridomyrmecin in a cephalic gland, and that these chemicals have a highly repellent effect on ants. Stereoselective synthesis of 4 stereoisomers of iridomyrmecin allowed us to demonstrate that the repellent effect of iridomyrmecins depends on the stereochemistry. Potential food items impregnated with natural doses of (-)-iridomyrmecin were avoided by ants much longer than those impregnated with (+)-iridomyrmecin, (+)-isoiridomyrmecin, or (-)-isoiridomyrmecin, respectively. Quantitative headspace analyses revealed furthermore that females and males of L. heterotoma released iridomyrmecins in higher amounts when confronted with ants. This is the first time, that (-)-iridomyrmecin and (+)-isoiridomyrmecin are reported as natural products. Females synthesize more iridomyrmecins than males, and the most active (-)-iridomyrmecin is produced by females only. We, therefore, hypothesize that this defense mechanism is used mainly by female wasps when foraging for Drosophila larvae on rotten fruits, but also may protect male wasps during dispersal. PMID:22477024

  15. Packaging and Delivery of Chemical Weapons: A Defensive Trojan Horse Stratagem in Chromodorid Nudibranchs

    PubMed Central

    Carbone, Marianna; Gavagnin, Margherita; Haber, Markus; Guo, Yue-Wei; Fontana, Angelo; Manzo, Emiliano; Genta-Jouve, Gregory; Tsoukatou, Maria; Rudman, William B.; Cimino, Guido; Ghiselin, Michael T.; Mollo, Ernesto

    2013-01-01

    Background Storage of secondary metabolites with a putative defensive role occurs in the so-called mantle dermal formations (MDFs) that are located in the more exposed parts of the body of most and very likely all members of an entire family of marine mollusks, the chromodorid nudibranchs (Gastropoda: Opisthobranchia). Given that these structures usually lack a duct system, the mechanism for exudation of their contents remains unclear, as does their adaptive significance. One possible explanation could be that they are adapted so as to be preferentially attacked by predators. The nudibranchs might offer packages containing highly repugnant chemicals along with parts of their bodies to the predators, as a defensive variant of the strategic theme of the Trojan horse. Methodology and Principal Findings We detected, by quantitative 1H-NMR, extremely high local concentrations of secondary metabolites in the MDFs of six species belonging to five chromodorid genera. The compounds were purified by chromatographic methods and subsequently evaluated for their feeding deterrent properties, obtaining dose-response curves. We found that only distasteful compounds are accumulated in the reservoirs at concentrations that far exceed the values corresponding to maximum deterrent activity in the feeding assays. Other basic evidence, both field and experimental, has been acquired to elucidate the kind of damage that the predators can produce on both the nudibranchs' mantles and the MDFs. Significance As a result of a long evolutionary process that has progressively led to the accumulation of defensive chemical weapons in localized anatomical structures, the extant chromodorid nudibranchs remain in place when molested, retracting respiratory and chemosensory organs, but offering readily accessible parts of their body to predators. When these parts are masticated or wounded by predators, breakage of the MDFs results in the release of distasteful compounds at extremely high

  16. Plant chemical defense against herbivores and pathogens: generalized defense or trade-offs?

    PubMed

    Biere, Arjen; Marak, Hamida B; van Damme, Jos M M

    2004-08-01

    Plants are often attacked by multiple enemies, including pathogens and herbivores. While many plant secondary metabolites show specific effects toward either pathogens or herbivores, some can affect the performance of both these groups of natural enemies and are considered to be "generalized defense compounds". We tested whether aucubin and catalpol, two iridoid glycosides present in ribwort plantain (Plantago lanceolata), confer in vivo resistance to both the generalist insect herbivore Spodoptera exigua and the biotrophic fungal pathogen Diaporthe adunca using plants from P. lanceolata lines that had been selected for high- and low-leaf iridoid glycoside concentrations for four generations. The lines differed approximately three-fold in the levels of these compounds. Plants from the high-selection line showed enhanced resistance to both S. exigua and D. adunca, as evidenced by a smaller lesion size and a lower fungal growth rate and spore production, and a lower larval growth rate and herbivory under both choice and no-choice conditions. Gravimetric analysis revealed that the iridoid glycosides acted as feeding deterrents to S. exigua, thereby reducing its food intake rate, rather than having post-ingestive toxic effects as predicted from in vitro effects of hydrolysis products. We suggest that the bitter taste of iridoid glycosides deters feeding by S. exigua, whereas the hydrolysis products formed after tissue damage following fungal infection mediate pathogen resistance. We conclude that iridoid glycosides in P. lanceolata can serve as broad-spectrum defenses and that selection for pathogen resistance could potentially result in increased resistance to generalist insect herbivores and vice versa, resulting in diffuse rather than pairwise coevolution. PMID:15146326

  17. Department of Defense Nuclear/Biological/Chemical (NBC) warfare defense. Annual report to Congress, June 1994. Final report, 1 October 1992-30 September 1993

    SciTech Connect

    Not Available

    1994-06-01

    The National Defense Authorization Act for Fiscal Year 1994, Public Law 103-160, Title XVII, Chemical and Biological Weapons Defense, section 1703, directed the Secretary of Defense to submit an assessment and a description of plans to improve readiness. The DoD objective is to enable our forces to survive, fight and win in NBC contaminated environments. Discussed are new management objectives impacted by declining resources and force structure versus an ever changing threat environment. Nuclear biological, Chemical, NBC, Defense, Logistics, Readiness, Training, Contamination avoidance, Protection, Decontamination.

  18. Effects of physical conditioning on heat tolerance in chemical-defense gear. Master's thesis

    SciTech Connect

    Nauss, M.M.

    1986-06-01

    Today the threat of chemical warfare is real. The only effective defense is the use of chemical defense gear and gas masks. Since they render chemical-warfare gases and liquids impermeable to penetration, they also prohibit sweat evaporation in conditions of thermal stress and thus, contribute to heat illness development. Historically, it has been the hot, humid tropics where United Nation's peacekeeping forces have been called, thus the use of chemical-defense gear in these regions is a realistic possibility and heat illness could affect the outcome of any mission carried out there. The human body only operates within a narrow range of core temparatures, and heat illness is the result of a breakdown in homeostasis. Many factors influence heat tolerance, thus maintaining core temperature within a safe range. Adequate hydration, acclimitization to heat, low body weight, young age, low alcohol intake, and physical fitness all contribute to heat tolerance. This proposal attempts to look specifically at the effect of physical conditioning on heat tolerance in chemical-defense gear as a possible solution to the heat-stress problem noted in this gear. Trainee graduates attending technical training schools at Lackland AFB, Texas, will be tested for maximum oxygen uptake (VO/2max) and heat tolerance time (HTT) in chemical defense gear on bicycle ergometers at Brooks AFB, Texas. Half of these subjects will be physically conditioned for 12 weeks.

  19. Chemical defense in harvestmen (arachnida, opiliones): do benzoquinone secretions deter invertebrate and vertebrate predators?

    PubMed

    Machado, Glauco; Carrera, Patricia C; Pomini, Armando M; Marsaioli, Anita J

    2005-11-01

    Two alkylated 1,4-benzoquinones were identified from the defensive secretion produced by the neotropical harvestman Goniosoma longipes (Gonyleptidae). They were characterized as 2,3-dimethyl-1,4-benzoquinone and 2-ethyl-3-methyl-1,4-benzoquinone. We tested the effectiveness of these benzoquinone secretions against several predator types, including invertebrates and vertebrates. Different predators were exposed to the harvestmen's gland secretion or to distilled water in laboratory bioassays. Our results indicate that secretions containing the 1,4-benzoquinones released by G. longipes can be an effective defense against predation, and that the effectiveness of the secretion is dependent on the predator type. The scent gland secretion repelled seven ant species, two species of large wandering spiders, and one frog species, but was not an effective defense against an opossum. Our study also demonstrates that the scent gland secretion of G. longipes can work as a chemical shield preventing the approach of three large predatory ants for at least 10 min. The chemical shield may protect the harvestman against successive attacks of the same ant worker and also allow the harvestman to flee before massive ant recruitment. Our data support the suggestion that chemical defenses may increase survival with some but not all potential predators. This variation in defense effectiveness may result from many interacting factors, including the attack strategy, size, learning ability, and physiology of the predators, as well as the chemical nature of the defensive compounds, type of emission, and amount of effluent released by the prey.

  20. Chemical inhibition of RNA viruses reveals REDD1 as a host defense factor.

    PubMed

    Mata, Miguel A; Satterly, Neal; Versteeg, Gijs A; Frantz, Doug; Wei, Shuguang; Williams, Noelle; Schmolke, Mirco; Peña-Llopis, Samuel; Brugarolas, James; Forst, Christian V; White, Michael A; García-Sastre, Adolfo; Roth, Michael G; Fontoura, Beatriz M A

    2011-10-01

    A chemical genetics approach was taken to identify inhibitors of NS1, a major influenza A virus virulence factor that inhibits host gene expression. A high-throughput screen of 200,000 synthetic compounds identified small molecules that reversed NS1-mediated inhibition of host gene expression. A counterscreen for suppression of influenza virus cytotoxicity identified naphthalimides that inhibited replication of influenza virus and vesicular stomatitis virus (VSV). The mechanism of action occurs through activation of REDD1 expression and concomitant inhibition of mammalian target of rapamycin complex 1 (mTORC1) via TSC1-TSC2 complex. The antiviral activity of naphthalimides was abolished in REDD1(-/-) cells. Inhibition of REDD1 expression by viruses resulted in activation of the mTORC1 pathway. REDD1(-/-) cells prematurely upregulated viral proteins via mTORC1 activation and were permissive to virus replication. In contrast, cells conditionally expressing high concentrations of REDD1 downregulated the amount of viral protein. Thus, REDD1 is a new host defense factor, and chemical activation of REDD1 expression represents a potent antiviral intervention strategy.

  1. Chemical inhibition of RNA viruses reveals REDD1 as a host defense factor.

    PubMed

    Mata, Miguel A; Satterly, Neal; Versteeg, Gijs A; Frantz, Doug; Wei, Shuguang; Williams, Noelle; Schmolke, Mirco; Peña-Llopis, Samuel; Brugarolas, James; Forst, Christian V; White, Michael A; García-Sastre, Adolfo; Roth, Michael G; Fontoura, Beatriz M A

    2011-10-01

    A chemical genetics approach was taken to identify inhibitors of NS1, a major influenza A virus virulence factor that inhibits host gene expression. A high-throughput screen of 200,000 synthetic compounds identified small molecules that reversed NS1-mediated inhibition of host gene expression. A counterscreen for suppression of influenza virus cytotoxicity identified naphthalimides that inhibited replication of influenza virus and vesicular stomatitis virus (VSV). The mechanism of action occurs through activation of REDD1 expression and concomitant inhibition of mammalian target of rapamycin complex 1 (mTORC1) via TSC1-TSC2 complex. The antiviral activity of naphthalimides was abolished in REDD1(-/-) cells. Inhibition of REDD1 expression by viruses resulted in activation of the mTORC1 pathway. REDD1(-/-) cells prematurely upregulated viral proteins via mTORC1 activation and were permissive to virus replication. In contrast, cells conditionally expressing high concentrations of REDD1 downregulated the amount of viral protein. Thus, REDD1 is a new host defense factor, and chemical activation of REDD1 expression represents a potent antiviral intervention strategy. PMID:21909097

  2. 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...

  3. Quantitative and qualitative shifts in defensive metabolites define chemical defense investment during leaf development in Inga, a genus of tropical trees.

    PubMed

    Wiggins, Natasha L; Forrister, Dale L; Endara, María-José; Coley, Phyllis D; Kursar, Thomas A

    2016-01-01

    Selective pressures imposed by herbivores are often positively correlated with investments that plants make in defense. Research based on the framework of an evolutionary arms race has improved our understanding of why the amount and types of defenses differ between plant species. However, plant species are exposed to different selective pressures during the life of a leaf, such that expanding leaves suffer more damage from herbivores and pathogens than mature leaves. We hypothesize that this differential selective pressure may result in contrasting quantitative and qualitative defense investment in plants exposed to natural selective pressures in the field. To characterize shifts in chemical defenses, we chose six species of Inga, a speciose Neotropical tree genus. Focal species represent diverse chemical, morphological, and developmental defense traits and were collected from a single site in the Amazonian rainforest. Chemical defenses were measured gravimetrically and by characterizing the metabolome of expanding and mature leaves. Quantitative investment in phenolics plus saponins, the major classes of chemical defenses identified in Inga, was greater for expanding than mature leaves (46% and 24% of dry weight, respectively). This supports the theory that, because expanding leaves are under greater selective pressure from herbivores, they rely more upon chemical defense as an antiherbivore strategy than do mature leaves. Qualitatively, mature and expanding leaves were distinct and mature leaves contained more total and unique metabolites. Intraspecific variation was greater for mature leaves than expanding leaves, suggesting that leaf development is canalized. This study provides a snapshot of chemical defense investment in a speciose genus of tropical trees during the short, few-week period of leaf development. Exploring the metabolome through quantitative and qualitative profiling enables a more comprehensive examination of foliar chemical defense investment.

  4. [Bile acids and endotoxins: physico-chemical defense of the body].

    PubMed

    Bertók, L

    1999-01-01

    The toxic effects of endotoxin--the cell wall component of Gram negative intestinal bacteria--under experimental conditions can be induced only when they are administered parenterally. However, in naturally occurring enteroendotoxemic diseases (e.g. septic and various shocks, etc.), the endotoxin absorbs from the intestinal tract. The cause and mode of translocation was unknown. The generally used experimental shock models differ from natural diseases only in the mode by which endotoxin enters the blood circulation. If the common bile ducts of rats were chronically cannulated (bile deprived animals) perorally administered endotoxin was absorbed from the intestinal canal into blood circulation and provoked endotoxin shock. The translocation of endotoxins and consequent shock can be prevented by sodium deoxycholate or natural biles. The bile acids can split the endotoxin macromolecule (atoxic fragments). A similar destructive detergent action might will be a significant factor against potential infectious agents with lipoprotein outer structure (e.g. so-called "big" viruses). This defense mechanism of macrooganisms based on the detergent activity of bile acids is called as physico-chemical defense system. On the basis of this knowledge the bile acids might be used in the prevention and therapy of some clinical processes (e.g. hepatorenal syndrome; psoriasis).

  5. Biogeography of Alaska paper birch (Betula neoalaskana): latitudinal patterns in chemical defense and plant architecture.

    PubMed

    Stevens, Michael T; Brown, Sarah C; Bothwell, Helen M; Bryant, John P

    2016-02-01

    The latitudinal herbivory-defense hypothesis (LHDH) predicts that plants near the equator will be more heavily defended against herbivores than are plants at higher latitudes. Although this idea is widely found in the literature, recent studies have called this biogeographic pattern into question. We sought to evaluate the LHDH in a high-latitude terrestrial ecosystem where fire and mammalian herbivores may contribute to selection for higher levels of defensive chemistry. To address this objective, we collected seeds of Alaska paper birch (Betula neoalaskana) from nine locations along two north-south transects between 55 degrees N and 62 degrees N latitudes in western, interior Canada. The birch seeds were planted in pots in a common garden in Madison, Wisconsin, USA. From the resulting seedlings, we determined levels of chemical defense by assessing the density of resin glands, which have been shown to be negatively correlated with browsing. To assess plant architectural traits such as height, mean individual leaf area, and root-to-shoot ratio, we harvested a subset of the birch seedlings. Further, we used these traits to examine growth-defense trade-offs. Contrary to the LHDH, we found a positive correlation between chemical defense and latitude. Investigating relationships with fire, we found a strong positive correlation between resin gland density and percentage of area annually burned (PAAB) around each collection location and also between PAAB and latitude. Additionally, birch seedlings originating from higher latitudes were shorter, smaller-leaved, and rootier than their lower-latitude counterparts. Growth-defense trade-offs were observed in negative correlations between resin gland density and height and leaf size. Seedlings with higher resin gland densities also allocated less biomass to shoots and more to roots. These results further call into question the LHDH and provide specific information about latitudinal trends in plant defense at high, northern

  6. Sexually transmitted chemical defense in a moth (Utetheisa ornatrix)

    PubMed Central

    González, Andrés; Rossini, Carmen; Eisner, Maria; Eisner, Thomas

    1999-01-01

    The arctiid moth Utetheisa ornatrix is protected against predation by pyrrolizidine alkaloids (PA) that it sequesters as a larva from its food plant. Earlier work had shown that males transmit PA to the female with the sperm package and that the female bestows part of this gift on the eggs, protecting these against predation as a result. We now show that the female herself derives protection from the gift. Females deficient in PA are vulnerable to predation from spiders (Lycosa ceratiola and Nephila clavipes). If mated with a PA-laden male, the females become unacceptable as prey. The effect takes hold promptly and endures; females are unacceptable to spiders virtually from the moment they uncouple from the male and remain unacceptable as they age. Chemical data showed that the female allocates the received PA quickly to all body parts. We predict that other instances will be found of female insects being rendered invulnerable by receipt of sexually transmitted chemicals. PMID:10318925

  7. United States national strategy and defense policy objectives after chemical disarmament. Study project

    SciTech Connect

    Harrison, D.G.; Roberts, J.R.

    1989-03-19

    Negotiations on a chemical weapons ban treaty have shown remarkable progress in recent years, so much in fact that it appears some kind of agreement may be reached in the next few years. The focus of this study is to define United States National Security Strategy and Defense Policy Objectives after chemical disarmament is achieved. Data on the problem were collected through open literature and interviews with key officials in the Department of Defense, and Department of State, to include the Arms Control and Disarmament Agency. The study emphasizes the changing threat in the Third World, a phenomenon that has accelerated in the last years. While a total verifiable ban on chemical weapons is a laudable goal, the possibility of such a treaty achieving the complete elimination of chemical threats is distinctly remote. While the United States, Soviet Union and thirty-eight other countries participating in the 40-nation Chemical Disarmament Conference have agreed 'in principle', many problems remain. (JES)

  8. Diatom/copepod interactions in plankton: the indirect chemical defense of unicellular algae.

    PubMed

    Pohnert, Georg

    2005-06-01

    Numerous coexisting species can be observed in the open oceans. This includes the complex community of the plankton, which comprises all free floating organisms in the sea. Traditionally, nutrient limitation, competition, predation, and abiotic factors have been assumed to shape the community structure in this environment. Only in recent years has the idea arisen that chemical signals and chemical defense can influence species interactions in the plankton as well. Key players at the base of the marine food web are diatoms (unicellular algae with silicified cell walls) and their main predators, the herbivorous copepods. It was assumed that diatoms represent a generally good food source for the grazers but recent work indicates that some species use chemical defenses. Secondary metabolites, released by these algae immediately after wounding, are targeted not against the predators themselves but rather at interfering with their reproductive success. This strategy allows diatoms to reduce the grazer population, thereby influencing the marine food web. This review addresses the chemical ecology of the defensive oxylipins formed by diatoms and the question of how these metabolites can act in such a dilute environment. Aspects of biosynthesis, bioassays, and the possible implications of such a chemical defense for the plankton community structure are also discussed.

  9. Host plant invests in growth rather than chemical defense when attacked by a specialist herbivore.

    PubMed

    Arab, Alberto; Trigo, José Roberto

    2011-05-01

    Plant defensive compounds may be a cost rather than a benefit when plants are attacked by specialist insects that may overcome chemical barriers by strategies such as sequestering plant compounds. Plants may respond to specialist herbivores by compensatory growth rather than chemical defense. To explore the use of defensive chemistry vs. compensatory growth we studied Brugmansia suaveolens (Solanaceae) and the specialist larvae of the ithomiine butterfly Placidina euryanassa, which sequester defensive tropane alkaloids (TAs) from this host plant. We investigated whether the concentration of TAs in B. suaveolens was changed by P. euryanassa damage, and whether plants invest in growth, when damaged by the specialist. Larvae feeding during 24 hr significantly decreased TAs in damaged plants, but they returned to control levels after 15 days without damage. Damaged and undamaged plants did not differ significantly in leaf area after 15 days, indicating compensatory growth. Our results suggest that B. suaveolens responds to herbivory by the specialist P. euryanassa by investing in growth rather than chemical defense.

  10. 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

  11. Chemical and physical defenses of Singapore gorgonians (Octocorallia: Gorgonacea).

    PubMed

    Koh; Goh; Chou; Tan

    2000-08-23

    Gorgonians are abundant in tropical waters and their polyps are seldom predated on. This study investigates how gorgonians defend themselves chemically and physically against fish predation. Gorgonian extracts and sclerites were incorporated into fish feed and tested on reef fishes. Laboratory bioassays using Greyhead wrasses, Halichoeres purpurescens, as well as field bioassays showed five gorgonian species from the family Ellisellidae and three from the family Plexauridae collected from Singapore reefs to be deterrent towards fishes. Bioassays of fractions obtained from subsequent fractionation suggested synergistic or additive effects between compounds present in gorgonians. Sclerites incorporated into fish feed in their natural concentrations were also tested for fish deterrence and were positive for only two gorgonian species from the family Ellisellidae.

  12. Do defensive chemicals facilitate intraguild predation and influence invasion success in ladybird beetles?

    PubMed

    Kajita, Yukie; Obrycki, John J; Sloggett, John J; Evans, Edward W; Haynes, Kenneth F

    2014-12-01

    Egg predation and cannibalism are believed to be common phenomena among many species of aphidophagous predatory ladybird beetles despite the presence of alkaloid based defensive chemicals in all life stages. We identified defensive chemicals from eggs of three congeneric species, one introduced into North America (Coccinella septempunctata L.), and two native (C. transversoguttata richardsoni Brown, and C. novemnotata Herbst), and examined the effects of ingested defensive chemicals on first instars. Ingested congeneric alkaloids were not toxic to first instars, likely because the three congeners produce the same principal alkaloids, precoccinelline and coccinelline, in similar amounts. First instars of the three congeners accumulated alkaloids ingested through egg cannibalism and congeneric predation. Egg consumption doubled the amount of alkaloids in first instars when they fed on conspecific or congeneric eggs, in comparison to a pea aphid diet. No detrimental effects of ingested congeneric alkaloids on development or survival of first instars were observed among these congeners. Chemical defenses of eggs are therefore not likely to be important in favoring the invasive species, C. septempunctata, in interactions with these native congeneric species. Because the invasive species is the most aggressive predator, having the same types of alkaloids may facilitate disproportionate intraguild predation on native congeners by C. septempunctata thereby potentially enhancing the invasion success of this introduced species. PMID:25380992

  13. Aspen defense chemicals influence midgut bacterial community composition of gypsy moth.

    PubMed

    Mason, Charles J; Rubert-Nason, Kennedy F; Lindroth, Richard L; Raffa, Kenneth F

    2015-01-01

    Microbial symbionts are becoming increasingly recognized as mediators of many aspects of plant - herbivore interactions. However, the influence of plant chemical defenses on gut associates of insect herbivores is less well understood. We used gypsy moth (Lymantria dispar L.), and differing trembling aspen (Populus tremuloides Michx.) genotypes that vary in chemical defenses, to assess the influence of foliar chemistry on bacterial communities of larval midguts. We evaluated the bacterial community composition of foliage, and of midguts of larvae feeding on those leaves, using next-generation high-throughput sequencing. Plant defense chemicals did not influence the composition of foliar communities. In contrast, both phenolic glycosides and condensed tannins affected the bacterial consortia of gypsy moth midguts. The two most abundant operational taxonomic units were classified as Ralstonia and Acinetobacter. The relative abundance of Ralstonia was higher in midguts than in foliage when phenolic glycoside concentrations were low, but lower in midguts when phenolic glycosides were high. In contrast, the relative abundance of Ralstonia was lower in midguts than in foliage when condensed tannin concentrations were low, but higher in midguts when condensed tannins were high. Acinetobacter showed a different relationship with host chemistry, being relatively more abundant in midguts than with foliage when condensed tannin concentrations were low, but lower in midguts when condensed tannins were high. Acinetobacter tended to have a greater relative abundance in midguts of insects feeding on genotypes with high phenolic glycoside concentrations. These results show that plant defense chemicals influence herbivore midgut communities, which may in turn influence host utilization.

  14. Do defensive chemicals facilitate intraguild predation and influence invasion success in ladybird beetles?

    PubMed

    Kajita, Yukie; Obrycki, John J; Sloggett, John J; Evans, Edward W; Haynes, Kenneth F

    2014-12-01

    Egg predation and cannibalism are believed to be common phenomena among many species of aphidophagous predatory ladybird beetles despite the presence of alkaloid based defensive chemicals in all life stages. We identified defensive chemicals from eggs of three congeneric species, one introduced into North America (Coccinella septempunctata L.), and two native (C. transversoguttata richardsoni Brown, and C. novemnotata Herbst), and examined the effects of ingested defensive chemicals on first instars. Ingested congeneric alkaloids were not toxic to first instars, likely because the three congeners produce the same principal alkaloids, precoccinelline and coccinelline, in similar amounts. First instars of the three congeners accumulated alkaloids ingested through egg cannibalism and congeneric predation. Egg consumption doubled the amount of alkaloids in first instars when they fed on conspecific or congeneric eggs, in comparison to a pea aphid diet. No detrimental effects of ingested congeneric alkaloids on development or survival of first instars were observed among these congeners. Chemical defenses of eggs are therefore not likely to be important in favoring the invasive species, C. septempunctata, in interactions with these native congeneric species. Because the invasive species is the most aggressive predator, having the same types of alkaloids may facilitate disproportionate intraguild predation on native congeners by C. septempunctata thereby potentially enhancing the invasion success of this introduced species.

  15. 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

  16. Defense-Inducing Volatiles: In Search of the Active Motif

    PubMed Central

    Lion, Ulrich; Boland, Wilhelm

    2008-01-01

    Herbivore-induced volatile organic compounds (VOCs) are widely appreciated as an indirect defense mechanism since carnivorous arthropods use VOCs as cues for host localization and then attack herbivores. Another function of VOCs is plant–plant signaling. That VOCs elicit defensive responses in neighboring plants has been reported from various species, and different compounds have been found to be active. In order to search for a structural motif that characterizes active VOCs, we used lima bean (Phaseolus lunatus), which responds to VOCs released from damaged plants with an increased secretion of extrafloral nectar (EFN). We exposed lima bean to (Z)-3-hexenyl acetate, a substance naturally released from damaged lima bean and known to induce EFN secretion, and to several structurally related compounds. (E)-3-hexenyl acetate, (E)-2-hexenyl acetate, 5-hexenyl acetate, (Z)-3-hexenylisovalerate, and (Z)-3-hexenylbutyrate all elicited significant increases in EFN secretion, demonstrating that neither the (Z)-configuration nor the position of the double-bond nor the size of the acid moiety are critical for the EFN-inducing effect. Our result is not consistent with previous concepts that postulate reactive electrophile species (Michael-acceptor-systems) for defense-induction in Arabidopsis. Instead, we postulate that physicochemical processes, including interactions with odorant binding proteins and resulting in changes in transmembrane potentials, can underlie VOCs-mediated signaling processes. PMID:18408973

  17. Chemical defense against fouling in the solitary ascidian Phallusia nigra.

    PubMed

    Mayzel, Boaz; Haber, Markus; Ilan, Micha

    2014-12-01

    The solitary ascidian Phallusia nigra is rarely fouled by epibionts. Here, we tested the antifouling activity of its crude extracts in laboratory and field assays. P. nigra extracts inhibited the growth of all eight tested environmental bacteria and two of four laboratory bacteria. Extracts of the sympatric, but fouled solitary ascidian Herdmania momus inhibited only one test bacterium. Scanning electron microscopy confirmed that the tunic surface of P. nigra is largely bacteria-free. Both ascidian extracts significantly inhibited the larval metamorphosis of the bryozoan Bugula neritina at the tested concentration range of 0.05-2 mg ml(-1). Both crude extracts were toxic to larvae of the brine shrimp Artemia salina at natural volumetric whole-tissue concentrations, but only P. nigra showed activity at 2 mg ml(-1) and below (LC50 = 1.11 mg ml(-1)). P. nigra crude extracts also significantly reduced the settlement of barnacles, polychaetes, and algae in Mediterranean field assays and barnacle settlement in Red Sea trials. Comparisons between control experiments and pH values monitored in all experiments indicate that the observed effects were not due to acidity of the organic extracts. Our results show that P. nigra secondary metabolites have antifouling activities, which may act in synergy with previously proposed physiological antifouling mechanisms. PMID:25572211

  18. Phylogenetic correlations among chemical and physical plant defenses change with ontogeny.

    PubMed

    Kariñho-Betancourt, Eunice; Agrawal, Anurag A; Halitschke, Rayko; Núñez-Farfán, Juan

    2015-04-01

    Theory predicts patterns of defense across taxa based on notions of tradeoffs and synergism among defensive traits when plants and herbivores coevolve. Because the expression of characters changes ontogenetically, the evolution of plant strategies may be best understood by considering multiple traits along a trajectory of plant development. Here we addressed the ontogenetic expression of chemical and physical defenses in 12 Datura species, and tested for macroevolutionary correlations between defensive traits using phylogenetic analyses. We used liquid chromatography coupled to mass spectrometry to identify the toxic tropane alkaloids of Datura, and also estimated leaf trichome density. We report three major patterns. First, we found different ontogenetic trajectories of alkaloids and leaf trichomes, with alkaloids increasing in concentration at the reproductive stage, whereas trichomes were much more variable across species. Second, the dominant alkaloids and leaf trichomes showed correlated evolution, with positive and negative associations. Third, the correlations between defensive traits changed across ontogeny, with significant relationships only occurring during the juvenile phase. The patterns in expression of defensive traits in the genus Datura are suggestive of adaptation to complex selective environments varying in space and time.

  19. Continue development of a biomedical data base on the medical aspects of chemical defense. Annual report

    SciTech Connect

    Landry, L.A.

    1986-12-01

    This report documents a one-year period of activities encompassing the further development and maintenance of the automated information system known as the Chemical Agent Retrieval System (CARS) for the U.S. Army Medical Research Institute of Chemical Defense (USAMRICD). During the period 18 November 1985 through 17 November 1986, Associate Consultants, Inc. (ACI), creator of the prototype system, expanded the database with relevant research articles taken from USAMRICD research reports and CRDEC holdings, medical and scientific libraries within the Washington area, and on-line searches of machine-readable database containing citations from the world-wide literature. ACI began entry of the results of these searches into the citation-tracking system file (CITES). To assist with automated retrieval of the documents, ACI wrote and tested a modular posting-switching program for expansion and maintenance of the thesaurus. ACI also initiated a study of the impact upon the contract of acquiring an Army-owned/ACI located VAX.

  20. Current knowledge and future research perspectives on cassava (Manihot esculenta Crantz) chemical defenses: An agroecological view.

    PubMed

    Pinto-Zevallos, Delia M; Pareja, Martín; Ambrogi, Bianca G

    2016-10-01

    Cassava (Manihot esculenta Crantz) is one of the most important staple crops worldwide. It constitutes the major source of carbohydrates for millions of low-income people living in rural areas, as well as a cash crop for smallholders in tropical and sub-tropical regions. The Food and Agriculture Organization of the United Nations predicts that cassava plantations will increase and production systems will intensify in the future, highlighting the need for developing strategies that improve the sustainability of production. Plant chemical defenses hold the potential for developing pest management strategies, as these plant traits can influence the behavior and performance of both pests and beneficial arthropods. Cassava plants are well-defended and produce a number of compounds involved in direct defense, such as cyanogenic glycosides, flavonoid glycosides, and hydroxycoumarins. In addition, volatile organic compounds induced upon herbivory and the secretion of extrafloral nectar act as indirect defense against herbivores by recruiting natural enemies. Here, cassava chemical defenses against pest arthropods are reviewed, with the aim of identifying gaps in our knowledge and areas of research that deserve further investigation for developing sound pest control strategies to improve sustainable production of this crop, and how these defenses can be used to benefit other crops. Cyanogenic content in cassava is also highly toxic to humans, and can cause irreversible health problems even at sub-lethal doses when consumed over prolonged periods. Therefore, the promotion of chemical defense in this crop should not aggravate these problems, and must be accompanied with the education on processing methods that reduce human exposure to cyanide. PMID:27316676

  1. Current knowledge and future research perspectives on cassava (Manihot esculenta Crantz) chemical defenses: An agroecological view.

    PubMed

    Pinto-Zevallos, Delia M; Pareja, Martín; Ambrogi, Bianca G

    2016-10-01

    Cassava (Manihot esculenta Crantz) is one of the most important staple crops worldwide. It constitutes the major source of carbohydrates for millions of low-income people living in rural areas, as well as a cash crop for smallholders in tropical and sub-tropical regions. The Food and Agriculture Organization of the United Nations predicts that cassava plantations will increase and production systems will intensify in the future, highlighting the need for developing strategies that improve the sustainability of production. Plant chemical defenses hold the potential for developing pest management strategies, as these plant traits can influence the behavior and performance of both pests and beneficial arthropods. Cassava plants are well-defended and produce a number of compounds involved in direct defense, such as cyanogenic glycosides, flavonoid glycosides, and hydroxycoumarins. In addition, volatile organic compounds induced upon herbivory and the secretion of extrafloral nectar act as indirect defense against herbivores by recruiting natural enemies. Here, cassava chemical defenses against pest arthropods are reviewed, with the aim of identifying gaps in our knowledge and areas of research that deserve further investigation for developing sound pest control strategies to improve sustainable production of this crop, and how these defenses can be used to benefit other crops. Cyanogenic content in cassava is also highly toxic to humans, and can cause irreversible health problems even at sub-lethal doses when consumed over prolonged periods. Therefore, the promotion of chemical defense in this crop should not aggravate these problems, and must be accompanied with the education on processing methods that reduce human exposure to cyanide.

  2. Defense of benthic invertebrates against surface colonization by larvae: a chemical arms race.

    PubMed

    Krug, P J

    2006-01-01

    Sessile invertebrates evolved in a competitive milieu where space is a limiting resource, setting off an arms race between adults that must maintain clean surfaces and larvae that must locate and attach to a suitable substratum. I review the evidence that invertebrates chemically deter or kill the propagules of fouling animals and protists under natural conditions, and that chemosensory mechanisms may allow larvae to detect and avoid settling on chemically protected organisms. The fouling process is an ecologically complex web of interactions between basibionts, surface-colonizing microbes, and fouling larvae, all mediated by chemical signaling. Host-specific bacterial communities are maintained by many invertebrates, and may inhibit fouling by chemical deterrence of larvae, or by preventing biofilm formation by inductive strains. Larval settlement naturally occurs in a turbulent environment, yet the effects of waterborne versus surface-adsorbed chemical defenses have not been compared in flow, limiting our understanding of how larvae respond to toxic surfaces in the field. The importance of evaluating alternative hypotheses such as mechanical and physical defense is discussed, as is the need for ecologically relevant bioassays that quantify effects on larval behavior and identify compounds likely to play a defensive role in situ.

  3. Packaging of chemicals in the defensive secretory glands of the sea hare Aplysia californica.

    PubMed

    Johnson, Paul M; Kicklighter, Cynthia E; Schmidt, Manfred; Kamio, Michiya; Yang, Hsiuchin; Elkin, Dimitry; Michel, William C; Tai, Phang C; Derby, Charles D

    2006-01-01

    Sea hares protect themselves from predatory attacks with several modes of chemical defenses. One of these is inking, which is an active release of a protective fluid upon predatory attack. In many sea hares including Aplysia californica and A. dactylomela, this fluid is a mixture of two secretions from two separate glands, usually co-released: ink, a purple fluid from the ink gland; and opaline, a white viscous secretion from the opaline gland. These two secretions are mixed in the mantle cavity and directed toward the attacking predator. Some of the chemicals in these secretions and their mechanism of action have been identified. In our study, we used western blots, immunocytochemistry, amino acid analysis, and bioassays to examine the distribution of these components: (1) an L-amino acid oxidase called escapin for A. californica and dactylomelin-P for A. dactylomela, which has antimicrobial activity but we believe its main function is in defending sea hares against predators that evoke its release; and (2) escapin's major amino acid substrates--L-lysine and L-arginine. Escapin is exclusively produced in the ink gland and is not present in any other tissues or secretions. Furthermore, escapin is only sequestered in the amber vesicles of the ink glandand not in the red-purple vesicles, which contain algal-derived chromophores that give ink its distinctive purple color. The concentration of escapin and dactylomelin-P in ink, both in the gland and after its release, is as high as 2 mg ml(-1), or 30 micromol ml(-1), which is well above its antimicrobial threshold. Lysine and arginine (and other amino acids) are packaged into vesicles in the ink and opaline glands, but arginine is present in ink and opaline at <1 mmol l(-1) and lysine is present in ink at <1 mmol l(-1) but in opaline at 65 mmol l(-1). Our previous results showed that both lysine and arginine mediate escapin's bacteriostatic effects, but only lysine mediates its bactericidal effects. Given that escapin

  4. Isolated and synergistic effects of chemical and structural defenses of two species of Tethya (Porifera: Demospongiae)

    NASA Astrophysics Data System (ADS)

    Ribeiro, Suzi Meneses; Cassiano, Keila Mara; Cavalcanti, Diana Negrão; Teixeira, Valéria Laneuville; Pereira, Renato Crespo

    2012-02-01

    Sponges are an important source of many interesting secondary metabolites with multiple ecological roles. Sponges can also use their spicules as a means of deterring consumers. The present study investigated the importance of chemicals and spicules as defensive strategies against predation for two congeneric sponge species from the Brazilian coast, Tethya rubra and Tethya maza. Crude extract and spicules differed somewhat in their effectiveness between these sponge species, with T. maza better defended than T. rubra against predation by the hermit crab Calcinus tibicen and synergistic effects stronger in T. rubra. These results show that defensive strategies may be similar between sponge species possessing monophyletic origin, and reveal the importance of research on congeneric species to understand the ecology and evolution of defensive strategies.

  5. Massive Activation of Archaeal Defense Genes during Viral Infection

    PubMed Central

    Voet, Marleen; Sismeiro, Odile; Dillies, Marie-Agnes; Jagla, Bernd; Coppée, Jean-Yves; Sezonov, Guennadi; Forterre, Patrick; van der Oost, John; Lavigne, Rob

    2013-01-01

    Archaeal viruses display unusually high genetic and morphological diversity. Studies of these viruses proved to be instrumental for the expansion of knowledge on viral diversity and evolution. The Sulfolobus islandicus rod-shaped virus 2 (SIRV2) is a model to study virus-host interactions in Archaea. It is a lytic virus that exploits a unique egress mechanism based on the formation of remarkable pyramidal structures on the host cell envelope. Using whole-transcriptome sequencing, we present here a global map defining host and viral gene expression during the infection cycle of SIRV2 in its hyperthermophilic host S. islandicus LAL14/1. This information was used, in combination with a yeast two-hybrid analysis of SIRV2 protein interactions, to advance current understanding of viral gene functions. As a consequence of SIRV2 infection, transcription of more than one-third of S. islandicus genes was differentially regulated. While expression of genes involved in cell division decreased, those genes playing a role in antiviral defense were activated on a large scale. Expression of genes belonging to toxin-antitoxin and clustered regularly interspaced short palindromic repeat (CRISPR)-Cas systems was specifically pronounced. The observed different degree of activation of various CRISPR-Cas systems highlights the specialized functions they perform. The information on individual gene expression and activation of antiviral defense systems is expected to aid future studies aimed at detailed understanding of the functions and interplay of these systems in vivo. PMID:23698312

  6. 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.

  7. Aspen defense chemicals influence midgut bacterial community composition of gypsy moth.

    PubMed

    Mason, Charles J; Rubert-Nason, Kennedy F; Lindroth, Richard L; Raffa, Kenneth F

    2015-01-01

    Microbial symbionts are becoming increasingly recognized as mediators of many aspects of plant - herbivore interactions. However, the influence of plant chemical defenses on gut associates of insect herbivores is less well understood. We used gypsy moth (Lymantria dispar L.), and differing trembling aspen (Populus tremuloides Michx.) genotypes that vary in chemical defenses, to assess the influence of foliar chemistry on bacterial communities of larval midguts. We evaluated the bacterial community composition of foliage, and of midguts of larvae feeding on those leaves, using next-generation high-throughput sequencing. Plant defense chemicals did not influence the composition of foliar communities. In contrast, both phenolic glycosides and condensed tannins affected the bacterial consortia of gypsy moth midguts. The two most abundant operational taxonomic units were classified as Ralstonia and Acinetobacter. The relative abundance of Ralstonia was higher in midguts than in foliage when phenolic glycoside concentrations were low, but lower in midguts when phenolic glycosides were high. In contrast, the relative abundance of Ralstonia was lower in midguts than in foliage when condensed tannin concentrations were low, but higher in midguts when condensed tannins were high. Acinetobacter showed a different relationship with host chemistry, being relatively more abundant in midguts than with foliage when condensed tannin concentrations were low, but lower in midguts when condensed tannins were high. Acinetobacter tended to have a greater relative abundance in midguts of insects feeding on genotypes with high phenolic glycoside concentrations. These results show that plant defense chemicals influence herbivore midgut communities, which may in turn influence host utilization. PMID:25475786

  8. Sequestered and Synthesized Chemical Defenses in the Poison Frog Melanophryniscus moreirae.

    PubMed

    Jeckel, Adriana M; Grant, Taran; Saporito, Ralph A

    2015-05-01

    Bufonid poison frogs of the genus Melanophryniscus contain alkaloid-based chemical defenses that are derived from a diet of alkaloid-containing arthropods. In addition to dietary alkaloids, bufadienolide-like compounds and indolealkylamines have been identified in certain species of Melanophryniscus. Our study reports, for the first time, the co-occurrence of large quantities of both alkaloids sequestered from the diet and an endogenously biosynthesized indolalkylamine in skin secretions from individual specimens of Melanophryniscus moreirae from Brazil. GC/MS analysis of 55 individuals of M. moreirae revealed 37 dietary alkaloids and the biosynthesized indolealkylamine bufotenine. On average, pumiliotoxin 267C, bufotenine, and allopumilitoxin 323B collectively represent ca. 90 % of the defensive chemicals present in an individual. The quantity of defensive chemicals differed between sexes, with males possessing significantly less dietary alkaloid and bufotenine than females. Most of the dietary alkaloids have structures with branched-chains, indicating they are likely derived from oribatid mites. The ratio of bufotenine:alkaloid quantity decreased with increasing quantities of dietary alkaloids, suggesting that M. moreirae might regulate bufotenine synthesis in relation to sequestration of dietary alkaloids. PMID:25902958

  9. Fitness costs of chemical defense in Plantago lanceolata L.: effects of nutrient and competition stress.

    PubMed

    Marak, Hamida B; Biere, Arjen; Van Damme, Jos M M

    2003-11-01

    Fitness costs of defense are often invoked to explain the maintenance of genetic variation in levels of chemical defense compounds in natural plant populations. We investigated fitness costs of iridoid glycosides (IGs), terpenoid compounds that strongly deter generalist insect herbivores, in ribwort plantain (Plantago lanceolata L.) using lines that had been artificially selected for high and low leaf IG concentrations for four generations. Twelve maternal half-sib families from each selection line were grown in four environments, consisting of two nutrient and two competition treatments. We tested whether: (1) in the absence of herbivores and pathogens, plants from lines selected for high IG levels have a lower fitness than plants selected for low IG levels; and (2) costs of chemical defense increase with environmental stress. Vegetative biomass did not differ between selection lines, but plants selected for high IG levels produced fewer inflorescences and had a significantly lower reproductive dry weight than plants selected for low IG levels, indicating a fitness cost of IG production. Line-by-nutrient and line-by-competition interactions were not significant for any of the fitness-related traits. Hence, there was no evidence that fitness costs increased with environmental stress. Two factors may have contributed to the absence of higher costs under environmental stress. First, IGs are carbon-based chemicals. Under nutrient limitation, the relative carbon excess may result in the production of IGs without imposing a further constraint on growth and reproduction. Second, correlated responses to selection on IG levels indicate the existence of a positive genetic association between IG level and cotyledon size. At low nutrient level, a path analysis based on family means revealed that in the presence of competitors, the negative direct effect of a high IG level on aboveground plant dry weight was partly offset by a positive direct effect of the associated larger

  10. A Specialist Herbivore Uses Chemical Camouflage to Overcome the Defenses of an Ant-Plant Mutualism

    PubMed Central

    Whitehead, Susan R.; Reid, Ellen; Sapp, Joseph; Poveda, Katja; Royer, Anne M.; Posto, Amanda L.; Kessler, André

    2014-01-01

    Many plants and ants engage in mutualisms where plants provide food and shelter to the ants in exchange for protection against herbivores and competitors. Although several species of herbivores thwart ant defenses and extract resources from the plants, the mechanisms that allow these herbivores to avoid attack are poorly understood. The specialist insect herbivore, Piezogaster reclusus (Hemiptera: Coreidae), feeds on Neotropical bull-horn acacias (Vachellia collinsii) despite the presence of Pseudomyrmex spinicola ants that nest in and aggressively defend the trees. We tested three hypotheses for how P. reclusus feeds on V. collinsii while avoiding ant attack: (1) chemical camouflage via cuticular surface compounds, (2) chemical deterrence via metathoracic defense glands, and (3) behavioral traits that reduce ant detection or attack. Our results showed that compounds from both P. reclusus cuticles and metathoracic glands reduce the number of ant attacks, but only cuticular compounds appear to be essential in allowing P. reclusus to feed on bull-horn acacia trees undisturbed. In addition, we found that ant attack rates to P. reclusus increased significantly when individuals were transferred between P. spinicola ant colonies. These results are consistent with the hypothesis that chemical mimicry of colony-specific ant or host plant odors plays a key role in allowing P. reclusus to circumvent ant defenses and gain access to important resources, including food and possibly enemy-free space. This interaction between ants, acacias, and their herbivores provides an excellent example of the ability of herbivores to adapt to ant defenses of plants and suggests that herbivores may play an important role in the evolution and maintenance of mutualisms. PMID:25047551

  11. 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.

  12. Tasty but protected--first evidence of chemical defense in oribatid mites.

    PubMed

    Heethoff, Michael; Koerner, Lars; Norton, Roy A; Raspotnig, Günther

    2011-09-01

    Oribatid mites (Acari, Oribatida) represent one of the most abundant and speciose groups of microarthropods in the decomposer food webs of soils, but little is known of their top-down regulation by predators. Oribatids are relatively long-lived and have numerous morphological defensive adaptations, and so have been proposed to live in 'enemy-free space'. Most also possess a pair of large exocrine oil glands that produce species-specific mixtures of hydrocarbons, terpenes, aromatics, and alkaloids with presumably allomonal functions, although their adaptive value has never been tested empirically. We developed a protocol that discharges the oil glands of the model oribatid species, Archegozetes longisetosus. and offered 'disarmed' individuals as prey to polyphagous Stenus beetles (Staphylinidae), using untreated mites as controls. Stenus juno fed on disarmed mites with behavioral sequences and success rates similar to those observed when they prey on springtails, a common prey. In contrast, mites from the control group with full glands were almost completely rejected; contact with the gland region elicited a strong reaction and cleaning behavior in the beetle. This is the first evidence of an adaptive value of oribatid mite oil gland secretions for chemical defense. The protocol of discharging oil glands should facilitate future studies on top-down control of oribatid mites that aim to differentiate between morphological and chemical aspects of defensive strategies.

  13. Desorption electrospray ionization mass spectrometry reveals surface-mediated antifungal chemical defense of a tropical seaweed

    PubMed Central

    Lane, Amy L.; Nyadong, Leonard; Galhena, Asiri S.; Shearer, Tonya L.; Stout, E. Paige; Parry, R. Mitchell; Kwasnik, Mark; Wang, May D.; Hay, Mark E.; Fernandez, Facundo M.; Kubanek, Julia

    2009-01-01

    Organism surfaces represent signaling sites for attraction of allies and defense against enemies. However, our understanding of these signals has been impeded by methodological limitations that have precluded direct fine-scale evaluation of compounds on native surfaces. Here, we asked whether natural products from the red macroalga Callophycus serratus act in surface-mediated defense against pathogenic microbes. Bromophycolides and callophycoic acids from algal extracts inhibited growth of Lindra thalassiae, a marine fungal pathogen, and represent the largest group of algal antifungal chemical defenses reported to date. Desorption electrospray ionization mass spectrometry (DESI-MS) imaging revealed that surface-associated bromophycolides were found exclusively in association with distinct surface patches at concentrations sufficient for fungal inhibition; DESI-MS also indicated the presence of bromophycolides within internal algal tissue. This is among the first examples of natural product imaging on biological surfaces, suggesting the importance of secondary metabolites in localized ecological interactions, and illustrating the potential of DESI-MS in understanding chemically-mediated biological processes. PMID:19366672

  14. Tasty but protected--first evidence of chemical defense in oribatid mites.

    PubMed

    Heethoff, Michael; Koerner, Lars; Norton, Roy A; Raspotnig, Günther

    2011-09-01

    Oribatid mites (Acari, Oribatida) represent one of the most abundant and speciose groups of microarthropods in the decomposer food webs of soils, but little is known of their top-down regulation by predators. Oribatids are relatively long-lived and have numerous morphological defensive adaptations, and so have been proposed to live in 'enemy-free space'. Most also possess a pair of large exocrine oil glands that produce species-specific mixtures of hydrocarbons, terpenes, aromatics, and alkaloids with presumably allomonal functions, although their adaptive value has never been tested empirically. We developed a protocol that discharges the oil glands of the model oribatid species, Archegozetes longisetosus. and offered 'disarmed' individuals as prey to polyphagous Stenus beetles (Staphylinidae), using untreated mites as controls. Stenus juno fed on disarmed mites with behavioral sequences and success rates similar to those observed when they prey on springtails, a common prey. In contrast, mites from the control group with full glands were almost completely rejected; contact with the gland region elicited a strong reaction and cleaning behavior in the beetle. This is the first evidence of an adaptive value of oribatid mite oil gland secretions for chemical defense. The protocol of discharging oil glands should facilitate future studies on top-down control of oribatid mites that aim to differentiate between morphological and chemical aspects of defensive strategies. PMID:21898169

  15. Chemical defense balanced by sequestration and de novo biosynthesis in a lepidopteran specialist.

    PubMed

    Fürstenberg-Hägg, Joel; Zagrobelny, Mika; Jørgensen, Kirsten; Vogel, Heiko; Møller, Birger Lindberg; Bak, Søren

    2014-01-01

    The evolution of sequestration (uptake and accumulation) relative to de novo biosynthesis of chemical defense compounds is poorly understood, as is the interplay between these two strategies. The Burnet moth Zygaena filipendulae (Lepidoptera) and its food-plant Lotus corniculatus (Fabaceae) poses an exemplary case study of these questions, as Z. filipendulae belongs to the only insect family known to both de novo biosynthesize and sequester the same defense compounds directly from its food-plant. Z. filipendulae and L. corniculatus both contain the two cyanogenic glucosides linamarin and lotaustralin, which are defense compounds that can be hydrolyzed to liberate toxic hydrogen cyanide. The overall amounts and ratios of linamarin and lotaustralin in Z. filipendulae are tightly regulated, and only to a low extent reflect the ratio in the ingested food-plant. We demonstrate that Z. filipendulae adjusts the de novo biosynthesis of CNglcs by regulation at both the transcriptional and protein level depending on food plant composition. Ultimately this ensures that the larva saves energy and nitrogen while maintaining an effective defense system to fend off predators. By using in situ PCR and immunolocalization, the biosynthetic pathway was resolved to the larval fat body and integument, which infers rapid replenishment of defense compounds following an encounter with a predator. Our study supports the hypothesis that de novo biosynthesis of CNglcs in Z. filipendulae preceded the ability to sequester, and facilitated a food-plant switch to cyanogenic plants, after which sequestration could evolve. Preservation of de novo biosynthesis allows fine-tuning of the amount and composition of CNglcs in Z. filipendulae.

  16. Variation in Chemical Defense Among Natural Populations of Common Toad, Bufo bufo, Tadpoles: the Role of Environmental Factors.

    PubMed

    Bókony, Veronika; Móricz, Ágnes M; Tóth, Zsófia; Gál, Zoltán; Kurali, Anikó; Mikó, Zsanett; Pásztor, Katalin; Szederkényi, Márk; Tóth, Zoltán; Ujszegi, János; Üveges, Bálint; Krüzselyi, Dániel; Capon, Robert J; Hoi, Herbert; Hettyey, Attila

    2016-04-01

    Defensive toxins are widespread in nature, yet we know little about how various environmental factors shape the evolution of chemical defense, especially in vertebrates. In this study we investigated the natural variation in the amount and composition of bufadienolide toxins, and the relative importance of ecological factors in predicting that variation, in larvae of the common toad, Bufo bufo, an amphibian that produces toxins de novo. We found that tadpoles' toxin content varied markedly among populations, and the number of compounds per tadpole also differed between two geographical regions. The most consistent predictor of toxicity was the strength of competition, indicating that tadpoles produced more compounds and larger amounts of toxins when coexisting with more competitors. Additionally, tadpoles tended to contain larger concentrations of bufadienolides in ponds that were less prone to desiccation, suggesting that the costs of toxin production can only be afforded by tadpoles that do not need to drastically speed up their development. Interestingly, this trade-off was not alleviated by higher food abundance, as periphyton biomass had negligible effect on chemical defense. Even more surprisingly, we found no evidence that higher predation risk enhances chemical defenses, suggesting that low predictability of predation risk and high mortality cost of low toxicity might select for constitutive expression of chemical defense irrespective of the actual level of predation risk. Our findings highlight that the variation in chemical defense may be influenced by environmental heterogeneity in both the need for, and constraints on, toxicity as predicted by optimal defense theory.

  17. Variation in Chemical Defense Among Natural Populations of Common Toad, Bufo bufo, Tadpoles: the Role of Environmental Factors.

    PubMed

    Bókony, Veronika; Móricz, Ágnes M; Tóth, Zsófia; Gál, Zoltán; Kurali, Anikó; Mikó, Zsanett; Pásztor, Katalin; Szederkényi, Márk; Tóth, Zoltán; Ujszegi, János; Üveges, Bálint; Krüzselyi, Dániel; Capon, Robert J; Hoi, Herbert; Hettyey, Attila

    2016-04-01

    Defensive toxins are widespread in nature, yet we know little about how various environmental factors shape the evolution of chemical defense, especially in vertebrates. In this study we investigated the natural variation in the amount and composition of bufadienolide toxins, and the relative importance of ecological factors in predicting that variation, in larvae of the common toad, Bufo bufo, an amphibian that produces toxins de novo. We found that tadpoles' toxin content varied markedly among populations, and the number of compounds per tadpole also differed between two geographical regions. The most consistent predictor of toxicity was the strength of competition, indicating that tadpoles produced more compounds and larger amounts of toxins when coexisting with more competitors. Additionally, tadpoles tended to contain larger concentrations of bufadienolides in ponds that were less prone to desiccation, suggesting that the costs of toxin production can only be afforded by tadpoles that do not need to drastically speed up their development. Interestingly, this trade-off was not alleviated by higher food abundance, as periphyton biomass had negligible effect on chemical defense. Even more surprisingly, we found no evidence that higher predation risk enhances chemical defenses, suggesting that low predictability of predation risk and high mortality cost of low toxicity might select for constitutive expression of chemical defense irrespective of the actual level of predation risk. Our findings highlight that the variation in chemical defense may be influenced by environmental heterogeneity in both the need for, and constraints on, toxicity as predicted by optimal defense theory. PMID:27059330

  18. Arbuscular mycorrhizal fungi alter above- and below-ground chemical defense expression differentially among Asclepias species.

    PubMed

    Vannette, Rachel L; Hunter, Mark D; Rasmann, Sergio

    2013-01-01

    Below-ground (BG) symbionts of plants can have substantial influence on plant growth and nutrition. Recent work demonstrates that mycorrhizal fungi can affect plant resistance to herbivory and the performance of above- (AG) and BG herbivores. Although these examples emerge from diverse systems, it is unclear if plant species that express similar defensive traits respond similarly to fungal colonization, but comparative work may inform this question. To examine the effects of arbuscular mycorrhizal fungi (AMF) on the expression of chemical resistance, we inoculated 8 species of Asclepias (milkweed)-which all produce toxic cardenolides-with a community of AMF. We quantified plant biomass, foliar and root cardenolide concentration and composition, and assessed evidence for a growth-defense tradeoff in the presence and absence of AMF. As expected, total foliar and root cardenolide concentration varied among milkweed species. Importantly, the effect of mycorrhizal fungi on total foliar cardenolide concentration also varied among milkweed species, with foliar cardenolides increasing or decreasing, depending on the plant species. We detected a phylogenetic signal to this variation; AMF fungi reduced foliar cardenolide concentrations to a greater extent in the clade including A. curassavica than in the clade including A. syriaca. Moreover, AMF inoculation shifted the composition of cardenolides in AG and BG plant tissues in a species-specific fashion. Mycorrhizal inoculation changed the relative distribution of cardenolides between root and shoot tissue in a species-specific fashion, but did not affect cardenolide diversity or polarity. Finally, a tradeoff between plant growth and defense in non-mycorrhizal plants was mitigated completely by AMF inoculation. Overall, we conclude that the effects of AMF inoculation on the expression of chemical resistance can vary among congeneric plant species, and ameliorate tradeoffs between growth and defense. PMID:24065971

  19. Convergent evolution of chemical defense in poison frogs and arthropod prey between Madagascar and the Neotropics.

    PubMed

    Clark, Valerie C; Raxworthy, Christopher J; Rakotomalala, Valérie; Sierwald, Petra; Fisher, Brian L

    2005-08-16

    With few exceptions, aposematically colored poison frogs sequester defensive alkaloids, unchanged, from dietary arthropods. In the Neotropics, myrmicine and formicine ants and the siphonotid millipede Rhinotus purpureus are dietary sources for alkaloids in dendrobatid poison frogs, yet the arthropod sources for Mantella poison frogs in Madagascar remained unknown. We report GC-MS analyses of extracts of arthropods and microsympatric Malagasy poison frogs (Mantella) collected from Ranomafana, Madagascar. Arthropod sources for 11 "poison frog" alkaloids were discovered, 7 of which were also detected in microsympatric Mantella. These arthropod sources include three endemic Malagasy ants, Tetramorium electrum, Anochetus grandidieri, and Paratrechina amblyops (subfamilies Myrmicinae, Ponerinae, and Formicinae, respectively), and the pantropical tramp millipede R. purpureus. Two of these ant species, A. grandidieri and T. electrum, were also found in Mantella stomachs, and ants represented the dominant prey type (67.3% of 609 identified stomach arthropods). To our knowledge, detection of 5,8-disubstituted (ds) indolizidine iso-217B in T. electrum represents the first izidine having a branch point in its carbon skeleton to be identified from ants, and detection of 3,5-ds pyrrolizidine 251O in A. grandidieri represents the first ponerine ant proposed as a dietary source of poison frog alkaloids. Endemic Malagasy ants with defensive alkaloids (with the exception of Paratrechina) are not closely related to any Neotropical species sharing similar chemical defenses. Our results suggest convergent evolution for the acquisition of defensive alkaloids in these dietary ants, which may have been the critical prerequisite for subsequent convergence in poison frogs between Madagascar and the Neotropics.

  20. Selective Chemical Inhibition of agr Quorum Sensing in Staphylococcus aureus Promotes Host Defense with Minimal Impact on Resistance

    PubMed Central

    Sully, Erin K.; Malachowa, Natalia; Elmore, Bradley O.; Alexander, Susan M.; Femling, Jon K.; Gray, Brian M.; DeLeo, Frank R.; Otto, Michael; Cheung, Ambrose L.; Edwards, Bruce S.; Sklar, Larry A.; Horswill, Alexander R.; Hall, Pamela R.; Gresham, Hattie D.

    2014-01-01

    Bacterial signaling systems are prime drug targets for combating the global health threat of antibiotic resistant bacterial infections including those caused by Staphylococcus aureus. S. aureus is the primary cause of acute bacterial skin and soft tissue infections (SSTIs) and the quorum sensing operon agr is causally associated with these. Whether efficacious chemical inhibitors of agr signaling can be developed that promote host defense against SSTIs while sparing the normal microbiota of the skin is unknown. In a high throughput screen, we identified a small molecule inhibitor (SMI), savirin (S. aureus virulence inhibitor) that disrupted agr-mediated quorum sensing in this pathogen but not in the important skin commensal Staphylococcus epidermidis. Mechanistic studies employing electrophoretic mobility shift assays and a novel AgrA activation reporter strain revealed the transcriptional regulator AgrA as the target of inhibition within the pathogen, preventing virulence gene upregulation. Consistent with its minimal impact on exponential phase growth, including skin microbiota members, savirin did not provoke stress responses or membrane dysfunction induced by conventional antibiotics as determined by transcriptional profiling and membrane potential and integrity studies. Importantly, savirin was efficacious in two murine skin infection models, abating tissue injury and selectively promoting clearance of agr+ but not Δagr bacteria when administered at the time of infection or delayed until maximal abscess development. The mechanism of enhanced host defense involved in part enhanced intracellular killing of agr+ but not Δagr in macrophages and by low pH. Notably, resistance or tolerance to savirin inhibition of agr was not observed after multiple passages either in vivo or in vitro where under the same conditions resistance to growth inhibition was induced after passage with conventional antibiotics. Therefore, chemical inhibitors can selectively target AgrA in

  1. Selective chemical inhibition of agr quorum sensing in Staphylococcus aureus promotes host defense with minimal impact on resistance.

    PubMed

    Sully, Erin K; Malachowa, Natalia; Elmore, Bradley O; Alexander, Susan M; Femling, Jon K; Gray, Brian M; DeLeo, Frank R; Otto, Michael; Cheung, Ambrose L; Edwards, Bruce S; Sklar, Larry A; Horswill, Alexander R; Hall, Pamela R; Gresham, Hattie D

    2014-06-01

    Bacterial signaling systems are prime drug targets for combating the global health threat of antibiotic resistant bacterial infections including those caused by Staphylococcus aureus. S. aureus is the primary cause of acute bacterial skin and soft tissue infections (SSTIs) and the quorum sensing operon agr is causally associated with these. Whether efficacious chemical inhibitors of agr signaling can be developed that promote host defense against SSTIs while sparing the normal microbiota of the skin is unknown. In a high throughput screen, we identified a small molecule inhibitor (SMI), savirin (S. aureus virulence inhibitor) that disrupted agr-mediated quorum sensing in this pathogen but not in the important skin commensal Staphylococcus epidermidis. Mechanistic studies employing electrophoretic mobility shift assays and a novel AgrA activation reporter strain revealed the transcriptional regulator AgrA as the target of inhibition within the pathogen, preventing virulence gene upregulation. Consistent with its minimal impact on exponential phase growth, including skin microbiota members, savirin did not provoke stress responses or membrane dysfunction induced by conventional antibiotics as determined by transcriptional profiling and membrane potential and integrity studies. Importantly, savirin was efficacious in two murine skin infection models, abating tissue injury and selectively promoting clearance of agr+ but not Δagr bacteria when administered at the time of infection or delayed until maximal abscess development. The mechanism of enhanced host defense involved in part enhanced intracellular killing of agr+ but not Δagr in macrophages and by low pH. Notably, resistance or tolerance to savirin inhibition of agr was not observed after multiple passages either in vivo or in vitro where under the same conditions resistance to growth inhibition was induced after passage with conventional antibiotics. Therefore, chemical inhibitors can selectively target AgrA in

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

    PubMed Central

    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). PMID:25368622

  3. Plant-associated bacteria degrade defense chemicals and reduce their adverse effects on an insect defoliator.

    PubMed

    Mason, Charles J; Couture, John J; Raffa, Kenneth F

    2014-07-01

    Phytophagous insects must contend with numerous secondary defense compounds that can adversely affect their growth and development. The gypsy moth (Lymantria dispar) is a polyphagous herbivore that encounters an extensive range of hosts and chemicals. We used this folivore and a primary component of aspen chemical defenses, namely, phenolic glycosides, to investigate if bacteria detoxify phytochemicals and benefit larvae. We conducted insect bioassays using bacteria enriched from environmental samples, analyses of the microbial community in the midguts of bioassay larvae, and in vitro phenolic glycoside metabolism assays. Inoculation with bacteria enhanced larval growth in the presence, but not absence, of phenolic glycosides in the artificial diet. This effect of bacteria on growth was observed only in larvae administered bacteria from aspen foliage. The resulting midgut community composition varied among the bacterial treatments. When phenolic glycosides were included in diet, the composition of midguts in larvae fed aspen bacteria was significantly altered. Phenolic glycosides increased population responses by bacteria that we found able to metabolize these compounds in liquid growth cultures. Several aspects of these results suggest that vectoring or pairwise symbiosis models are inadequate for understanding microbial mediation of plant-herbivore interactions in some systems. First, bacteria that most benefitted larvae were initially foliar residents, suggesting that toxin-degrading abilities of phyllosphere inhabitants indirectly benefit herbivores upon ingestion. Second, assays with single bacteria did not confer the benefits to larvae obtained with consortia, suggesting multi- and inter-microbial interactions are also involved. Our results show that bacteria mediate insect interactions with plant defenses but that these interactions are community specific and highly complex. PMID:24798201

  4. Will chemical defenses become more effective against specialist herbivores under elevated CO2?

    PubMed

    Landosky, John M; Karowe, David N

    2014-10-01

    Elevated atmospheric CO2 is known to affect plant-insect herbivore interactions. Elevated CO2 causes leaf nitrogen to decrease, the ostensible cause of herbivore compensatory feeding. CO2 may also affect herbivore consumption by altering chemical defenses via changes in plant hormones. We considered the effects of elevated CO2, in conjunction with soil fertility and damage (simulated herbivory), on glucosinolate concentrations of mustard (Brassica nigra) and collard (B. oleracea var. acephala) and the effects of leaf nitrogen and glucosinolate groups on specialist Pieris rapae consumption. Elevated CO2 affected B. oleracea but not B. nigra glucosinolates; responses to soil fertility and damage were also species-specific. Soil fertility and damage also affected B. oleracea glucosinolates differently under elevated CO2. Glucosinolates did not affect P. rapae consumption at either CO2 concentration in B. nigra, but had CO2-specific effects on consumption in B. oleracea. At ambient CO2, leaf nitrogen had strong effects on glucosinolate concentrations and P. rapae consumption but only gluconasturtiin was a feeding stimulant. At elevated CO2, direct effects of leaf nitrogen were weaker, but glucosinolates had stronger effects on consumption. Gluconasturtiin and aliphatic glucosinolates were feeding stimulants and indole glucosinolates were feeding deterrents. These results do not support the compensatory feeding hypothesis as the sole driver of changes in P. rapae consumption under elevated CO2. Support for hormone-mediated CO2 response (HMCR) was mixed; it explained few treatment effects on constitutive or induced glucosinolates, but did explain patterns in SEMs. Further, the novel feeding deterrent effect of indole glucosinolates under elevated CO2 in B. oleracae underscores the importance of defensive chemistry in CO2 response. We speculate that P. rapae indole glucosinolate detoxification mechanisms may have been overwhelmed under elevated CO2 forcing slowed

  5. Will chemical defenses become more effective against specialist herbivores under elevated CO2?

    PubMed

    Landosky, John M; Karowe, David N

    2014-10-01

    Elevated atmospheric CO2 is known to affect plant-insect herbivore interactions. Elevated CO2 causes leaf nitrogen to decrease, the ostensible cause of herbivore compensatory feeding. CO2 may also affect herbivore consumption by altering chemical defenses via changes in plant hormones. We considered the effects of elevated CO2, in conjunction with soil fertility and damage (simulated herbivory), on glucosinolate concentrations of mustard (Brassica nigra) and collard (B. oleracea var. acephala) and the effects of leaf nitrogen and glucosinolate groups on specialist Pieris rapae consumption. Elevated CO2 affected B. oleracea but not B. nigra glucosinolates; responses to soil fertility and damage were also species-specific. Soil fertility and damage also affected B. oleracea glucosinolates differently under elevated CO2. Glucosinolates did not affect P. rapae consumption at either CO2 concentration in B. nigra, but had CO2-specific effects on consumption in B. oleracea. At ambient CO2, leaf nitrogen had strong effects on glucosinolate concentrations and P. rapae consumption but only gluconasturtiin was a feeding stimulant. At elevated CO2, direct effects of leaf nitrogen were weaker, but glucosinolates had stronger effects on consumption. Gluconasturtiin and aliphatic glucosinolates were feeding stimulants and indole glucosinolates were feeding deterrents. These results do not support the compensatory feeding hypothesis as the sole driver of changes in P. rapae consumption under elevated CO2. Support for hormone-mediated CO2 response (HMCR) was mixed; it explained few treatment effects on constitutive or induced glucosinolates, but did explain patterns in SEMs. Further, the novel feeding deterrent effect of indole glucosinolates under elevated CO2 in B. oleracae underscores the importance of defensive chemistry in CO2 response. We speculate that P. rapae indole glucosinolate detoxification mechanisms may have been overwhelmed under elevated CO2 forcing slowed

  6. Stress, chemical defense agents, and cholinergic receptors. Midterm report, 1 November 1987-31 July 1989

    SciTech Connect

    Lane, J.D.

    1989-11-30

    This project is assessing the affects of exposure to a chemical defense agent on anxiety and stress, by using rat models of anxiety (conditioned emotional response (CER); conditioned suppression) and unconditioned non-specific stres (exposure to footshock). The specific experiments determined the plasticity of muscarinic cholinergic binding sites in the central nervous system. The neuroanatomical locus and neuropharmacological profile of changes in binding sites were assessed in brain areas enriched in cholinergic markers. Acetylcholine turnover was measured to determine if the receptor response is compensatory or independent. The effects of acute exposure to doses of a chemical defense agent (soman--XGD) on lethality and behaviors were examined. The experiments involved training and conditioning adult rats to CER using standard operant/respondent techniques. The binding of radiolabelled ligand was studied in vitro using brain membranes and tissue sections (autoradiography). The major findings are that CER produces increases in acetylcholine turnover in brain areas involved in anxiety, and that primarily post-synaptic M1 receptors compensatorly decrease in response. These neurochemical phenomena are directly correlated with several behaviors, including onset and extinction of CER and non-specific stress. Followup experiments have been designed to test the interaction of CER, XGD and neurochemistry.

  7. Cranberry Resistance to Dodder Parasitism: Induced Chemical Defenses and Behavior of a Parasitic Plant.

    PubMed

    Tjiurutue, Muvari Connie; Sandler, Hilary A; Kersch-Becker, Monica F; Theis, Nina; Adler, Lynn A

    2016-02-01

    Parasitic plants are common in many ecosystems, where they can structure community interactions and cause major economic damage. For example, parasitic dodder (Cuscuta spp.) can cause up to 80-100 % yield loss in heavily infested cranberry (Vaccinium macrocarpon) patches. Despite their ecological and economic importance, remarkably little is known about how parasitic plants affect, or are affected by, host chemistry. To examine chemically-mediated interactions between dodder and its cranberry host, we conducted a greenhouse experiment asking whether: (1) dodder performance varies with cranberry cultivar; (2) cultivars differ in levels of phytohormones, volatiles, or phenolics, and whether such variation correlates with dodder parasitism; (3) dodder parasitism induced changes in phytohormones, volatiles, or phenolics, and whether the level of inducible response varied among cultivars. We used five cranberry cultivars to assess host attractiveness to dodder and dodder performance. Dodder performance did not differ across cultivars, but there were marginally significant differences in host attractiveness to dodder, with fewer dodder attaching to Early Black than to any other cultivar. Dodder parasitism induced higher levels of salicylic acid (SA) across cultivars. Cultivars differed in overall levels of flavonols and volatile profiles, but not phenolic acids or proanthocyanidins, and dodder attachment induced changes in several flavonols and volatiles. While cultivars differed slightly in resistance to dodder attachment, we did not find evidence of chemical defenses that mediate these interactions. However, induction of several defenses indicates that parasitism alters traits that could influence subsequent interactions with other species, thus shaping community dynamics. PMID:26905738

  8. Chemical defenses of the sacoglossan mollusk Elysia rufescens and its host Alga bryopsis sp.

    PubMed

    Becerro, M A; Goetz, G; Paul, V J; Scheuer, P J

    2001-11-01

    Sacoglossans are a group of opisthobranch mollusks that have been the source of numerous secondary metabolites; however, there are few examples where a defensive ecological role for these compounds has been demonstrated experimentally. We investigated the deterrent properties of the sacoglossan Elysia rufescens and its food alga Bryopsis sp. against natural fish predators. Bryopsis sp. produces kahalalide F, a major depsipeptide that is accumulated by the sacoglossan and that shows in vitro cytotoxicity against several cancer cell lines. Our data show that both Bryopsis sp. and Elysia rufescens are chemically protected against fish predators, as indicated by the deterrent properties of their extracts at naturally occurring concentrations. Following bioassay-guided fractionation, we observed that the antipredatory compounds of Bryopsis sp. were present in the butanol and chloroform fractions, both containing the depsipeptide kahalalide F. Antipredatory compounds of Elysia rufescens were exclusively present in the dichloromethane fraction. Further bioassay-guided fractionation led to the isolation of kahalalide F as the only compound responsible for the deterrent properties of the sacoglossan. Our data show that kahalalide F protects both Brvopsis sp. and Elysia rufescens from fish predation. This is the first report of a diet-derived depsipeptide used as a chemical defense in a sacoglossan.

  9. Community complexity drives patterns of natural selection on a chemical defense of Brassica nigra.

    PubMed

    Lankau, Richard A; Strauss, Sharon Y

    2008-02-01

    Plants interact with many different species throughout their life cycle. Recent work has shown that the ecological effects of multispecies interactions are often not predictable from studies of the component pairwise interactions. Little is known about how multispecies interactions affect the evolution of ecologically important traits. We tested the direct and interactive effects of inter- and intraspecific competition, as well as of two abundant herbivore species (a generalist folivore and a specialist aphid), on the selective value of a defensive chemical compound in Brassica nigra. We found that investment in chemical defense was favored in interspecific competition but disfavored in intraspecific competition and that this pattern of selection was dependent on the presence of both herbivores, suggesting that selection will depend on the rarity or commonness of these species. These results show that the selective value of ecologically important traits depends on the complicated web of interactions present in diverse natural communities and that fluctuations in community composition may maintain genetic variation in such traits.

  10. Orientations of psychotic activity in defensive pathological organizations.

    PubMed

    Williams, Paul

    2014-06-01

    The author reviews some clinical experiences of the treatment of personality disordered patients suffering from internal domination of ego functioning by a defensive pathological organization. In particular, the function and purpose of perverse, sadistic attacks by the organization on the ego are considered and questions pertaining to technique are raised. It is suggested that different forms of sadistic, subjugating activity by pathological organizations may denote differences in intent borne of the type and severity of the psychopathology of the individual. Patients with severe narcissistic psychopathology for whom object contact has become associated with the arousal of intense psychotic anxieties seem more likely to be subjected to an invasive, annihilatory imperative by the pathological organization, the purpose of which appears to be to obliterate the experience of contact with any differentiated object, to avoid emotion and to use coercion to enforce a primitive identification by the ego with the psychotic organization in the mind. Certain patients with less severe narcissistic psychopathology, yet for whom object contact can also be associated with the arousal of psychotic anxieties due to intense or persistent conflict with the object, sometimes expressed as organized sadomasochistic clinging to a punishing and punished object (for example, in certain borderline or depressed patients) exhibit sadistic attacks that serve less to annihilate object contact and more to intrusively control and punish the object. Observations of these phenomena have been made by a number of psychoanalysts in recent decades and these contributions are discussed. This paper is addressed primarily to the implications for technique with such patients, particularly a need for triangulation of their experiences of oppression in order to loosen the controls over the ego by the pathological organization. PMID:24620792

  11. Chemical and Physical Defense Traits in Two Sexual Forms of Opuntia robusta in Central Eastern Mexico

    PubMed Central

    Janczur, Mariusz Krzysztof; León Solano, Héctor Javier; Solache Rámos, Lupita Tzenyatze; Mendoza Reyes, Citlalli Hypatia; Oro Cerro, María del Carmen; Mariezcurrena Berasain, María Dolores; Rivas Manzano, Irma Victoria; Manjarrez, Javier; Villareal Benitez, José Luis; Czarnoleski, Marcin

    2014-01-01

    Sexually dimorphic plants provide an excellent opportunity for examining the differences in the extent of their defense against herbivores because they exhibit sex-related differences in reproductive investment. Such differences enable comparison of the sex with high reproduction expenses with the sex that expends less. The more costly sex is usually also better defended against herbivores. Generally, females are considered more valuable than hermaphrodites in terms of fitness; however, hermaphrodites are more valuable if they can produce seed by autonomous selfing, provided that the inbreeding depression is low and pollen is limited. We studied a gynodioecious population of Opuntia robusta from Central-Eastern Mexico, which has been reported to be trioecious, dioecious, or hermaphrodite, and addressed the following questions: 1) Is the hermaphrodite's reproductive output higher than the female's, and are hermaphrodites thus better defended? 2) Are plant tissues differentially defended? 3) Do trade-offs exist among different physical defense traits? and 4) among physical and chemical defense traits? We found that 1) hermaphrodites had a higher seed output and more spines per areola than females and that their spines contained less moisture. Non-reproductive hermaphrodite cladodes contained more total phenolic compounds (TPCs) than female ones. In addition, 2) hermaphrodite reproductive cladodes bore more spines than female cladodes, and 3) and 4) we found a negative relationship between spine number per areola and areola number per cladode and a positive relationship between spine number per areola per plant and TPC concentration per plant. Non-reproductive hermaphrodite cladodes contained a higher concentration of TPCs than female cladodes, and parental cladodes contained fewer TPCs than both reproductive and empty cladodes. PMID:24599143

  12. New hemiketal steroid from the introduced soft coral Chromonephthea braziliensis is a chemical defense against predatory fishes.

    PubMed

    Fleury, Beatriz G; Lages, Bruno G; Barbosa, Jussara P; Kaiser, Carlos R; Pinto, Angelo C

    2008-08-01

    Recent studies show that chemical defenses in the exotic soft coral Chromonephthea braziliensis Ofwegen (Nephtheidae, Alcyonacea) can be one of the reasons for the success of this introduced species. We report for the first time the detailed composition of the monohydroxylated sterol fraction and a new hemiketal steroid, 23-keto-cladiellin-A, isolated from the unpalatable hexane extract from C. braziliensis. Bioassay-guided fractionation of this extract revealed that this hemiketal steroid exhibits potent feeding deterrent properties against a natural assemblage of fishes at the natural concentration. The major sterol fraction, containing the monohydroxylated sterols, was inactive in the bioassay. The results suggest that this active molecule may be driving the observed success of the invasion of this soft coral along the Brazilian Atlantic coast.

  13. Chemical-defense flight-glove ensemble evaluation. Final report, June 1986-February 1987

    SciTech Connect

    Ross, J.; Ervin, C.

    1987-06-01

    Four chemical-defense flight-glove ensembles were evaluated for their effect on manual dexterity. Two- and three-layer combinations included in the study were: cotton liner/7-mil butyl/Nomex; cotton liner/12.5-mil epichlorohydron butyl/Nomex; Nomex/7-mil butyl (no liner); and, Nomex/12.5-mil epichlorohydron butyl (no liner). Fifteen male and 15 female subjects performed five dexterity tests bare-handed and while wearing each of the glove ensembles. Results indicated that, as expected, all gloved conditions produced significantly poorer performances that did the bare-handed condition, and two-layer combinations resulted in consistently better performances that did the three-layer combinations. Although subjects' performance were least impaired by the Nomex/butyl 7 combination, the butyl 7 gloves tended to tear. For this reason, the two-layer combinations of Nomex/epichlorohydron butyl 12.5 appears to be the most practical ensemble.

  14. Metabolomics to Decipher the Chemical Defense of Cereals against Fusarium graminearum and Deoxynivalenol Accumulation

    PubMed Central

    Gauthier, Léa; Atanasova-Penichon, Vessela; Chéreau, Sylvain; Richard-Forget, Florence

    2015-01-01

    Fusarium graminearum is the causal agent of Fusarium head blight (FHB) and Gibberella ear rot (GER), two devastating diseases of wheat, barley, and maize. Furthermore, F. graminearum species can produce type B trichothecene mycotoxins that accumulate in grains. Use of FHB and GER resistant cultivars is one of the most promising strategies to reduce damage induced by F. graminearum. Combined with genetic approaches, metabolomic ones can provide powerful opportunities for plant breeding through the identification of resistant biomarker metabolites which have the advantage of integrating the genetic background and the influence of the environment. In the past decade, several metabolomics attempts have been made to decipher the chemical defense that cereals employ to counteract F. graminearum. By covering the major classes of metabolites that have been highlighted and addressing their potential role, this review demonstrates the complex and integrated network of events that cereals can orchestrate to resist to F. graminearum. PMID:26492237

  15. Active-passive bistatic surveillance for long range air defense

    SciTech Connect

    Wardrop, B.; Molyneux-Berry, M.R.B. )

    1992-06-01

    A hypothetical mobile support receiver capable of working within existing and future air defense networks as a means to maintain essential surveillance functions is considered. It is shown how multibeam receiver architecture supported by digital signal processing can substantially improve surveillance performance against chaff and jamming threats. A dual-mode support receiver concept is proposed which is based on the state-of-the-art phased-array technology, modular processing in industry standard hardware and existing networks. 20 refs.

  16. Integrated defense system overlaps as a disease model: with examples for multiple chemical sensitivity.

    PubMed Central

    Rowat, S C

    1998-01-01

    The central nervous, immune, and endocrine systems communicate through multiple common messengers. Over evolutionary time, what may be termed integrated defense system(s) (IDS) have developed to coordinate these communications for specific contexts; these include the stress response, acute-phase response, nonspecific immune response, immune response to antigen, kindling, tolerance, time-dependent sensitization, neurogenic switching, and traumatic dissociation (TD). These IDSs are described and their overlap is examined. Three models of disease production are generated: damage, in which IDSs function incorrectly; inadequate/inappropriate, in which IDS response is outstripped by a changing context; and evolving/learning, in which the IDS learned response to a context is deemed pathologic. Mechanisms of multiple chemical sensitivity (MCS) are developed from several IDS disease models. Model 1A is pesticide damage to the central nervous system, overlapping with body chemical burdens, TD, and chronic zinc deficiency; model 1B is benzene disruption of interleukin-1, overlapping with childhood developmental windows and hapten-antigenic spreading; and model 1C is autoimmunity to immunoglobulin-G (IgG), overlapping with spreading to other IgG-inducers, sudden spreading of inciters, and food-contaminating chemicals. Model 2A is chemical and stress overload, including comparison with the susceptibility/sensitization/triggering/spreading model; model 2B is genetic mercury allergy, overlapping with: heavy metals/zinc displacement and childhood/gestational mercury exposures; and model 3 is MCS as evolution and learning. Remarks are offered on current MCS research. Problems with clinical measurement are suggested on the basis of IDS models. Large-sample patient self-report epidemiology is described as an alternative or addition to clinical biomarker and animal testing. Images Figure 1 Figure 2 Figure 3 Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 PMID:9539008

  17. Defensive chemicals of tawny crazy ants, Nylanderia fulva and their toxicity to red imported fire ants (Hymenoptera: Formicidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Nylanderia fulva (Mayr) has been reported as being able to displace Solenopsis invicta Buren, one of the most aggressive invasive ants in the world. Like S. invicta, N. fulva use chemical secretions in their defense/offense, which may contribute to their observed superior competition ability. In t...

  18. Use of chemical variation and predation as plant defenses byEncelia farinosa against a specialist herbivore.

    PubMed

    Wisdom, C S

    1985-11-01

    Larvae of the monophagous herbivore,Trirhabda geminata, selectively eat particular plants and plant parts of its natural host,Encelia farinosa. Measurements of leaf damage and larval positions on branches through time support this observation. Time-lapse movie photography revealed that larvae are sufficiently mobile to search most of a plant in a 48-hr period and that aggregations were the result of larval activity and not directly the result of oviposition. Experiments withT. geminata larvae on artificial diets containing a range of natural concentrations of chemical extracts fromE. farinosa leaves showed that the larvae grew significantly slower and had a lower overall survivorship at the high concentration. Combining the results of all choice tests, larvae appeared unable to distinguish between high- and low-concentration agar diets. Considered individually, larval preferences for natural production concentrations changed as the season progressed. Early-season larvae preferred low-concentration leaves, while late-season larvae preferred high-concentrations. Measurements of chemical and nitrogen content of leaves selected by larvae in the field confirmed this pattern. Percent parasitism in field-collected larvae increased with season as the larval population decreased. This combination of slowed growth and increasing parasitism and predation is a putative defense strategy ofEncelia farinosa to prevent adaptation by a specialist herbivore to the total range of compounds elaborated.

  19. Disruption of web structure and predatory behavior of a spider by plant-derived chemical defenses of an aposematic aphid.

    PubMed

    Malcolm, S B

    1989-06-01

    Two toxic and bitter-tasting cardenolides (cardiac-active steroids) were sequestered by the brightly colored oleander aphid,Aphis nerii B. de F., from the neotropical milkweed host plantAsclepias curassavica L. After feeding on milkweed-reared aphids, the orb-web spiderZygiella x-notata (Clerck) built severely disrupted webs and attacked fewer nontoxic, control aphids, whereas the webs of spiders fed only nontoxic aphids remained intact. The regularity and size of the prey-trapping area of webs were reduced significantly in proportion to the amount of toxic aphids eaten. The effects of toxic aphids on spider web structure were mimicked by feeding spiders the bitter-tasting cardenolide digitoxin, a cardenolide with similar steroidal structure and pharmacological activity to the two aphid cardenolides. These results show that the well-known effects of psychoactive drugs on spider web structure are more than interesting behavioral assays of drag activity. Similar effects, produced by plant-derived chemicals in the spider's aphid prey, are relevant to the ecology and evolution of interactions between prey defense and predator foraging.

  20. 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

  1. A defense in depth approach to radiation protection for 125I production activities.

    PubMed

    Culp, T; Potter, C A

    2001-08-01

    Not all operational radiation protection situations lend themselves to simple solutions. Often a Radiation Protection Program must be developed and implemented for difficult situations. A defense in depth approach to radiation protection was developed for 125I production activities. Defense in depth relies on key radiation protection elements that tend to be mutually supportive and in combination provide reasonable assurance that the overall desired level of protection has been provided. For difficult situations, defense in depth can provide both a reasonable and appropriate approach to radiation protection.

  2. The defensive secretion of Carabus lefebvrei Dejean 1826 pupa (Coleoptera, Carabidae): gland ultrastructure and chemical identification.

    PubMed

    Giglio, Anita; Brandmayr, Pietro; Dalpozzo, Renato; Sindona, Giovanni; Tagarelli, Antonio; Talarico, Federica; Brandmayr, Tullia Zetto; Ferrero, Enrico A

    2009-05-01

    This study documents the defensive function of flavored humor secreted by the abdominal glands of Carabus lefebvrei pupae. The morphology and the ultrastructure of these glands were described and the volatile compounds of glands secretion were identified by gas chromatography/mass spectrometry. The ultrastructure analysis shows an acinose complex formed by about 50 clusters. Each cluster has 20 glandular units and the unit-composed of one secretory and one canal cell lying along a duct-belongs to the class 3 cell type of Quennedey (1998). In the cytoplasm, the secretory cell contains abundant rough endoplasmatic reticula, glycogen granules, numerous mitochondria, and many well-developed Golgi complexes producing electron-dense secretory granules. Mitochondria are large, elongated, and often adjoining electronlucent vesicles. The kind and the origin of secretory granules varying in size and density were discussed. The chemical analysis of the gland secretion revealed the presence of a mixture of low molecular weight terpenes, ketones, aldehydes, alcohols, esters, and carboxylic acids. Monoterpenes, especially linalool, were the major products. We supposed that ketones, aldehydes, alcohols, esters, and carboxylic acids have a deterrent function against the predators and monoterpenes provide a prophylaxis function against pathogens.

  3. Contact lens wear with the USAF Protective Integrated Hood/Mask chemical defense ensemble.

    PubMed

    Dennis, R J; Miller, R E; Peterson, R D; Jackson, W G

    1992-07-01

    The Protective Integrated Hood/Mask (PIHM) chemical defense aircrew ensemble blows air from the mask's plenum across the visor at a rate of approximately 15 L/min in order to prevent fogging of the visor and to cool the aircrew member's face. This study was designed to determine the effect of the PIHM airflow on soft contact lens (SCL) dehydration, contact lens comfort, and corneal integrity. There were 26 subjects who participated in this study: 15 SCL wearers, 6 rigid gas-permeable (RGP) wearers, and 5 nonspectacle wearing controls. Contrast acuity with the 3 Regan charts, subjective comfort, and relative humidity (RH) and temperature readings under the PIHM mask were monitored every 0.5 h during 6-h laboratory rides. Slit-lamp examinations and SCL water content measurements with a hand-held Abbe refractometer were made before and after the rides. High RH under the mask may have accounted for the moderate SCL dehydration (8.3%), no decrease in contrast acuity for any group, and lack of corneal stress. Although all groups experienced some inferior, epithelial, punctate keratopathy, RGP wearers had the most significant. SCLs performed relatively well in the PIHM mask environment. Testing with other parameter designs is necessary before recommending RGPs with the PIHM system. PMID:1616430

  4. Geographic variation in feeding preference of a generalist herbivore: the importance of seaweed chemical defenses.

    PubMed

    McCarty, Amanda T; Sotka, Erik E

    2013-08-01

    The ecological impacts of generalist herbivores depend on feeding preferences, which can vary across and within herbivore species. Among mesoherbivores, geographic variation in host use can occur because host plants have a more restricted geographic distribution than does the herbivore, or there is local evolution in host preference, or both. We tested the role of local evolution using the marine amphipod Ampithoe longimana by rearing multiple amphipod populations from three regions (subtropical Florida, warm-temperate North Carolina and cold-temperate New England) and assaying their feeding preferences toward ten seaweeds that occur in some but not all regions. Six of the ten seaweeds produce anti-herbivore secondary metabolites, and we detected geographic variation in feeding preference toward five (Dictyota menstrualis, Dictyota ciliolata, Fucus distichus, Chondrus crispus and Padina gymnospora, but not Caulerpa sertularioides). Amphipod populations that co-occur with a chemically-rich seaweed tended to have stronger feeding preferences for that seaweed, relative to populations that do not co-occur with the seaweed. A direct test indicated that geographic variation in feeding preference toward one seaweed (D. ciliolata) is mediated by feeding tolerance for lipophilic secondary metabolites. Among the four seaweeds that produce no known secondary metabolites (Acanthophora, Ectocarpus, Gracilaria and Hincksia/Feldmannia spp.), we detected no geographic variation in feeding preference. Thus, populations are more likely to evolve greater feeding preferences for local hosts when those hosts produce secondary metabolites. Microevolution of feeding behaviors of generalist marine consumers likely depends on the availability and identity of local hosts and the strength of their chemical defenses. PMID:23263529

  5. Geographic variation in feeding preference of a generalist herbivore: the importance of seaweed chemical defenses.

    PubMed

    McCarty, Amanda T; Sotka, Erik E

    2013-08-01

    The ecological impacts of generalist herbivores depend on feeding preferences, which can vary across and within herbivore species. Among mesoherbivores, geographic variation in host use can occur because host plants have a more restricted geographic distribution than does the herbivore, or there is local evolution in host preference, or both. We tested the role of local evolution using the marine amphipod Ampithoe longimana by rearing multiple amphipod populations from three regions (subtropical Florida, warm-temperate North Carolina and cold-temperate New England) and assaying their feeding preferences toward ten seaweeds that occur in some but not all regions. Six of the ten seaweeds produce anti-herbivore secondary metabolites, and we detected geographic variation in feeding preference toward five (Dictyota menstrualis, Dictyota ciliolata, Fucus distichus, Chondrus crispus and Padina gymnospora, but not Caulerpa sertularioides). Amphipod populations that co-occur with a chemically-rich seaweed tended to have stronger feeding preferences for that seaweed, relative to populations that do not co-occur with the seaweed. A direct test indicated that geographic variation in feeding preference toward one seaweed (D. ciliolata) is mediated by feeding tolerance for lipophilic secondary metabolites. Among the four seaweeds that produce no known secondary metabolites (Acanthophora, Ectocarpus, Gracilaria and Hincksia/Feldmannia spp.), we detected no geographic variation in feeding preference. Thus, populations are more likely to evolve greater feeding preferences for local hosts when those hosts produce secondary metabolites. Microevolution of feeding behaviors of generalist marine consumers likely depends on the availability and identity of local hosts and the strength of their chemical defenses.

  6. Passive and active defense in toads: the parotoid macroglands in Rhinella marina and Rhaebo guttatus.

    PubMed

    Mailho-Fontana, Pedro L; Antoniazzi, Marta M; Toledo, Luís F; Verdade, Vanessa K; Sciani, Juliana M; Barbaro, Katia C; Pimenta, Daniel C; Rodrigues, Miguel T; Jared, Carlos

    2014-02-01

    Amphibians have many skin poison glands used in passive defense, in which the aggressor causes its own poisoning when biting prey. In some amphibians the skin glands accumulate in certain regions forming macroglands, such as the parotoids of toads. We have discovered that the toad Rhaebo guttatus is able to squirt jets of poison towards the aggressor, contradicting the typical amphibian defense. We studied the R. guttatus chemical defense, comparing it with Rhinella marina, a sympatric species showing typical toad passive defense. We found that only in R. guttatus the parotoid is adhered to the scapula and do not have a calcified dermal layer. In addition, in this species, the plugs obstructing the glandular ducts are more fragile when compared to R. marina. As a consequence, the manual pressure necessary to extract the poison from the parotoid is twice as high in R. marina when compared to that used in R. guttatus. Compared to R. marina, the poison of R. guttatus is less lethal, induces edema and provokes nociception four times more intense. We concluded that the ability of R. guttatus to voluntary squirt poison is directly related to its stereotyped defensive behavior, together with the peculiar morphological characteristics of its parotoids. Since R. guttatus poison is practically not lethal, it is possibly directed to predators' learning, causing disturbing effects such as pain and edema. The unique mechanism of defense of R. guttatus may mistakenly justify the popular myth that toads, in general, squirt poison into people's eyes. PMID:24130001

  7. Chemical defense of the eastern newt (Notophthalmus viridescens): variation in efficiency against different consumers and in different habitats.

    PubMed

    Marion, Zachary H; Hay, Mark E

    2011-01-01

    Amphibian secondary metabolites are well known chemically, but their ecological functions are poorly understood--even for well-studied species. For example, the eastern newt (Notophthalmus viridescens) is a well known secretor of tetrodotoxin (TTX), with this compound hypothesized to facilitate this salamander's coexistence with a variety of aquatic consumers across the eastern United States. However, this assumption of chemical defense is primarily based on observational data with low replication against only a few predator types. Therefore, we tested the hypothesis that N. viridescens is chemically defended against co-occurring fishes, invertebrates, and amphibian generalist predators and that this defense confers high survivorship when newts are transplanted into both fish-containing and fishless habitats. We found that adult eastern newts were unpalatable to predatory fishes (Micropterus salmoides, Lepomis macrochirus) and a crayfish (Procambarus clarkii), but were readily consumed by bullfrogs (Lithobates catesbeianus). The eggs and neonate larvae were also unpalatable to fish (L. macrochirus). Bioassay-guided fractionation confirmed that deterrence is chemical and that ecologically relevant concentrations of TTX would deter feeding. Despite predatory fishes rejecting eastern newts in laboratory assays, field experiments demonstrated that tethered newts suffered high rates of predation in fish-containing ponds. We suggest that this may be due to predation by amphibians (frogs) and reptiles (turtles) that co-occur with fishes rather than from fishes directly. Fishes suppress invertebrate consumers that prey on bullfrog larvae, leading to higher bullfrog densities in fish containing ponds and thus considerable consumption of newts due to bullfrog tolerance of newt chemical defenses. Amphibian chemical defenses, and consumer responses to them, may be more complex and indirect than previously appreciated. PMID:22164212

  8. Chemical defense of the eastern newt (Notophthalmus viridescens): variation in efficiency against different consumers and in different habitats.

    PubMed

    Marion, Zachary H; Hay, Mark E

    2011-01-01

    Amphibian secondary metabolites are well known chemically, but their ecological functions are poorly understood--even for well-studied species. For example, the eastern newt (Notophthalmus viridescens) is a well known secretor of tetrodotoxin (TTX), with this compound hypothesized to facilitate this salamander's coexistence with a variety of aquatic consumers across the eastern United States. However, this assumption of chemical defense is primarily based on observational data with low replication against only a few predator types. Therefore, we tested the hypothesis that N. viridescens is chemically defended against co-occurring fishes, invertebrates, and amphibian generalist predators and that this defense confers high survivorship when newts are transplanted into both fish-containing and fishless habitats. We found that adult eastern newts were unpalatable to predatory fishes (Micropterus salmoides, Lepomis macrochirus) and a crayfish (Procambarus clarkii), but were readily consumed by bullfrogs (Lithobates catesbeianus). The eggs and neonate larvae were also unpalatable to fish (L. macrochirus). Bioassay-guided fractionation confirmed that deterrence is chemical and that ecologically relevant concentrations of TTX would deter feeding. Despite predatory fishes rejecting eastern newts in laboratory assays, field experiments demonstrated that tethered newts suffered high rates of predation in fish-containing ponds. We suggest that this may be due to predation by amphibians (frogs) and reptiles (turtles) that co-occur with fishes rather than from fishes directly. Fishes suppress invertebrate consumers that prey on bullfrog larvae, leading to higher bullfrog densities in fish containing ponds and thus considerable consumption of newts due to bullfrog tolerance of newt chemical defenses. Amphibian chemical defenses, and consumer responses to them, may be more complex and indirect than previously appreciated.

  9. Seasonal fluctuations in chemical defenses against macrofouling in Fucus vesiculosus and Fucus serratus from the Baltic Sea.

    PubMed

    Rickert, Esther; Karsten, Ulf; Pohnert, Georg; Wahl, Martin

    2015-01-01

    Macroalgae, especially perennial species, are exposed to a seasonally variable fouling pressure. It was hypothesized that macroalgae regulate their antifouling defense to fouling pressure. Over one year, the macrofouling pressure and the chemical anti-macrofouling defense strength of the brown algae Fucus vesiculosus and Fucus serratus were assessed with monthly evaluation. The anti-macrofouling defense was assessed by means of surface-extracted Fucus metabolites tested at near-natural concentrations in a novel in situ bioassay. Additionally, the mannitol content of both Fucus species was determined to assess resource availability for defense production. The surface chemistry of both Fucus species exhibited seasonal variability in attractiveness to Amphibalanus improvisus and Mytilus edulis. Of this variability, 50-60% is explained by a sinusoidal model. Only F. vesiculosus extracts originating from the spring and summer significantly deterred settlement of A. improvisus. The strength of macroalgal antifouling defense did not correlate either with in situ macrofouling pressure or with measured mannitol content, which, however, were never depleted. PMID:26023861

  10. Feeding on Host Plants with Different Concentrations and Structures of Pyrrolizidine Alkaloids Impacts the Chemical-Defense Effectiveness of a Specialist Herbivore

    PubMed Central

    Cunha, Beatriz P.; Solferini, Vera N.

    2015-01-01

    Sequestration of chemical defenses from host plants is a strategy widely used by herbivorous insects to avoid predation. Larvae of the arctiine moth Utetheisa ornatrix feeding on unripe seeds and leaves of many species of Crotalaria (Leguminosae) sequester N-oxides of pyrrolizidine alkaloids (PAs) from these host plants, and transfer them to adults through the pupal stage. PAs confer protection against predation on all life stages of U. ornatrix. As U. ornatrix also uses other Crotalaria species as host plants, we evaluated whether the PA chemical defense against predation is independent of host plant use. We fed larvae from hatching to pupation with either leaves or seeds of one of eight Crotalaria species (C. incana, C. juncea, C. micans, C. ochroleuca, C. pallida, C. paulina, C. spectabilis, and C. vitellina), and tested if adults were preyed upon or released by the orb-weaving spider Nephila clavipes. We found that the protection against the spider was more effective in adults whose larvae fed on seeds, which had a higher PA concentration than leaves. The exceptions were adults from larvae fed on C. paulina, C. spectabilis and C. vitellina leaves, which showed high PA concentrations. With respect to the PA profile, we describe for the first time insect-PAs in U. ornatrix. These PAs, biosynthesized from the necine base retronecine of plant origin, or monocrotaline- and senecionine-type PAs sequestered from host plants, were equally active in moth chemical defense, in a dose-dependent manner. These results are also partially explained by host plant phylogeny, since PAs of the host plants do have a phylogenetic signal (clades with high and low PA concentrations in leaves) which is reflected in the adult defense. PMID:26517873

  11. Feeding on Host Plants with Different Concentrations and Structures of Pyrrolizidine Alkaloids Impacts the Chemical-Defense Effectiveness of a Specialist Herbivore.

    PubMed

    Martins, Carlos H Z; Cunha, Beatriz P; Solferini, Vera N; Trigo, José R

    2015-01-01

    Sequestration of chemical defenses from host plants is a strategy widely used by herbivorous insects to avoid predation. Larvae of the arctiine moth Utetheisa ornatrix feeding on unripe seeds and leaves of many species of Crotalaria (Leguminosae) sequester N-oxides of pyrrolizidine alkaloids (PAs) from these host plants, and transfer them to adults through the pupal stage. PAs confer protection against predation on all life stages of U. ornatrix. As U. ornatrix also uses other Crotalaria species as host plants, we evaluated whether the PA chemical defense against predation is independent of host plant use. We fed larvae from hatching to pupation with either leaves or seeds of one of eight Crotalaria species (C. incana, C. juncea, C. micans, C. ochroleuca, C. pallida, C. paulina, C. spectabilis, and C. vitellina), and tested if adults were preyed upon or released by the orb-weaving spider Nephila clavipes. We found that the protection against the spider was more effective in adults whose larvae fed on seeds, which had a higher PA concentration than leaves. The exceptions were adults from larvae fed on C. paulina, C. spectabilis and C. vitellina leaves, which showed high PA concentrations. With respect to the PA profile, we describe for the first time insect-PAs in U. ornatrix. These PAs, biosynthesized from the necine base retronecine of plant origin, or monocrotaline- and senecionine-type PAs sequestered from host plants, were equally active in moth chemical defense, in a dose-dependent manner. These results are also partially explained by host plant phylogeny, since PAs of the host plants do have a phylogenetic signal (clades with high and low PA concentrations in leaves) which is reflected in the adult defense.

  12. Anticonvulsant and analgesic activities of crude extract and its fractions of the defensive secretion from the Mediterranean sponge, Spongia officinalis

    PubMed Central

    2012-01-01

    This study progresses in the direction of identifying component(s) from the Mediterranean sponge, Spongia officinalis with anticonvulsant and analgesic activities. We investigated the efficacy of crude extract and its semi-purified fractions (F1-F3) of the defensive secretion from Spongia officinalis for their in vivo anticonvulsant activity using the pentylenetetrazole (PTZ) seizure model and analgesic activity using the writhing test in mice. Among the series the crude extract exhibited interesting analgesic activity in a dose dependent manner. Similarly the fraction F2 showed a partial protection of mice from PTZ-induced seizure and interesting analgesic activity in a dose dependent manner. The purification and the determination of chemical structure(s) of compound(s) of this active fraction are under investigation. PMID:22494441

  13. 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.

  14. Chemical defenses and resource trade-offs structure sponge communities on Caribbean coral reefs.

    PubMed

    Loh, Tse-Lynn; Pawlik, Joseph R

    2014-03-18

    Ecological studies have rarely been performed at the community level across a large biogeographic region. Sponges are now the primary habitat-forming organisms on Caribbean coral reefs. Recent species-level investigations have demonstrated that predatory fishes (angelfishes and some parrotfishes) differentially graze sponges that lack chemical defenses, while co-occurring, palatable species heal, grow, reproduce, or recruit at faster rates than defended species. Our prediction, based on resource allocation theory, was that predator removal would result in a greater proportion of palatable species in the sponge community on overfished reefs. We tested this prediction by performing surveys of sponge and fish community composition on reefs having different levels of fishing intensity across the Caribbean. A total of 109 sponge species was recorded from 69 sites, with the 10 most common species comprising 51.0% of sponge cover (3.6-7.7% per species). Nonmetric multidimensional scaling indicated that the species composition of sponge communities depended more on the abundance of sponge-eating fishes than geographic location. Across all sites, multiple-regression analyses revealed that spongivore abundance explained 32.8% of the variation in the proportion of palatable sponges, but when data were limited to geographically adjacent locations with strongly contrasting levels of fishing pressure (Cayman Islands and Jamaica; Curaçao, Bonaire, and Martinique), the adjusted R(2) values were much higher (76.5% and 94.6%, respectively). Overfishing of Caribbean coral reefs, particularly by fish trapping, removes sponge predators and is likely to result in greater competition for space between faster-growing palatable sponges and endangered reef-building corals. PMID:24567392

  15. Chemical defenses and resource trade-offs structure sponge communities on Caribbean coral reefs.

    PubMed

    Loh, Tse-Lynn; Pawlik, Joseph R

    2014-03-18

    Ecological studies have rarely been performed at the community level across a large biogeographic region. Sponges are now the primary habitat-forming organisms on Caribbean coral reefs. Recent species-level investigations have demonstrated that predatory fishes (angelfishes and some parrotfishes) differentially graze sponges that lack chemical defenses, while co-occurring, palatable species heal, grow, reproduce, or recruit at faster rates than defended species. Our prediction, based on resource allocation theory, was that predator removal would result in a greater proportion of palatable species in the sponge community on overfished reefs. We tested this prediction by performing surveys of sponge and fish community composition on reefs having different levels of fishing intensity across the Caribbean. A total of 109 sponge species was recorded from 69 sites, with the 10 most common species comprising 51.0% of sponge cover (3.6-7.7% per species). Nonmetric multidimensional scaling indicated that the species composition of sponge communities depended more on the abundance of sponge-eating fishes than geographic location. Across all sites, multiple-regression analyses revealed that spongivore abundance explained 32.8% of the variation in the proportion of palatable sponges, but when data were limited to geographically adjacent locations with strongly contrasting levels of fishing pressure (Cayman Islands and Jamaica; Curaçao, Bonaire, and Martinique), the adjusted R(2) values were much higher (76.5% and 94.6%, respectively). Overfishing of Caribbean coral reefs, particularly by fish trapping, removes sponge predators and is likely to result in greater competition for space between faster-growing palatable sponges and endangered reef-building corals.

  16. Chemical defense in Elodea nuttallii reduces feeding and growth of aquatic herbivorous Lepidoptera.

    PubMed

    Erhard, Daniela; Pohnert, Georg; Gross, Elisabeth M

    2007-08-01

    The submersed macrophyte Elodea nuttallii (Hydrocharitaceae) is invasive in Europe and frequently found in aquatic plant communities. Many invertebrate herbivores, such as larvae of the generalist aquatic moth, Acentria ephemerella (Lepidoptera, Pyralidae), avoid feeding on E. nuttallii and preferably consume native species. First instar larvae exhibited a high mortality on E. nuttallii compared to the native macrophyte Potamogeton perfoliatus. Mortality of older larvae was also high when fed E. nuttallii exposed to high light intensities. Growth of older larvae was strongly reduced on E. nuttallii compared to pondweeds (Potamogeton lucens). Neither differences in nitrogen nor phosphorus content explained the different performance on these submerged macrophytes, but plants differed in their flavonoid content. To investigate whether plant-derived allelochemicals from E. nuttallii affect larval performance in the same way as live plants, we developed a functional bioassay, in which Acentria larvae were reared on artificial diets. We offered larvae Potamogeton leaf disks coated with crude Elodea extracts and partially purified flavonoids. Elodea extracts deterred larvae from feeding on otherwise preferred Potamogeton leaves, and yet, unknown compounds in the extracts reduced growth and survival of Acentria. The flavonoid fraction containing luteolin-7-O-diglucuronide, apigenin-7-O-diglucuronide, and chrysoeriol-7-O-diglucuronide strongly reduced feeding of larvae, but did not increase mortality. The concentrations of these compounds in our assays were 0.01-0.09% of plant dry mass, which is in the lower range of concentrations found in the field (0.02-1.2%). Chemical defense in E. nuttallii thus plays an ecologically relevant role in this aquatic plant-herbivore system. PMID:17577598

  17. Chemical defenses of crucifers: elicitation and metabolism of phytoalexins and indole-3-acetonitrile in brown mustard and turnip.

    PubMed

    Pedras, M Soledade C; Nycholat, Corwin M; Montaut, Sabine; Xu, Yiming; Khan, Abdul Q

    2002-03-01

    The metabolism of the cruciferous phytoalexins brassinin and cyclobrassinin, and the related compounds indole-3-carboxaldehyde, glucobrassicin, and indole-3-acetaldoxime was investigated in various plant tissues of Brassica juncea and B. rapa. Metabolic studies with brassinin showed that stems of B. juncea metabolized radiolabeled brassinin to indole-3-acetic acid, via indole-3-carboxaldehyde, a detoxification pathway similar to that followed by the "blackleg" fungus (Phoma lingam/Leptosphaeria maculans). In addition, it was established that tetradeuterated brassinin was incorporated into the phytoalexin brassilexin in B. juncea and B. rapa. On the other hand, the tetradeuterated indole glucosinolate glucobrassicin was not incorporated into brassinin, although the chemical structures of brassinins and indole glucosinolates suggest an interconnected biogenesis. Importantly, tetradeuterated indole-3-acetaldoxime was an efficient precursor of phytoalexins brassinin, brassilexin, and spirobrassinin. Elicitation experiments in tissues of Brassica juncea and B. rapa showed that indole-3-acetonitrile was an inducible metabolite produced in leaves and stems of B. juncea but not in B. rapa. Indole-3-acetonitrile displayed antifungal activity similar to that of brassilexin, was metabolized by the blackleg fungus at slower rates than brassinin, cyclobrassinin, or brassilexin, and appeared to be involved in defense responses of B. juncea.

  18. Leaf surface lipophilic compounds as one of the factors of silver birch chemical defense against larvae of gypsy moth.

    PubMed

    Martemyanov, Vyacheslav V; Pavlushin, Sergey V; Dubovskiy, Ivan M; Belousova, Irina A; Yushkova, Yuliya V; Morosov, Sergey V; Chernyak, Elena I; Glupov, Victor V

    2015-01-01

    Plant chemical defense against herbivores is a complex process which involves a number of secondary compounds. It is known that the concentration of leaf surface lipophilic compounds (SLCs), particularly those of flavonoid aglycones are increased with the defoliation treatment of silver birch Betula pendula. In this study we investigated how the alteration of SLCs concentration in the food affects the fitness and innate immunity of the gypsy moth Lymantria dispar. We found that a low SLCs concentrations in consumed leaves led to a rapid larval development and increased females' pupae weight (= fecundity) compared to larvae fed with leaves with high SLCs content. Inversely, increasing the compounds concentration in an artificial diet produced the reverse effects: decreases in both larval weight and larval survival. Low SLCs concentrations in tree leaves differently affected larval innate immunity parameters. For both sexes, total hemocytes count in the hemolymph increased, while the activity of plasma phenoloxidase decreased when larvae consume leaves with reduced content of SLCs. Our results clearly demonstrate that the concentration of SLCs in silver birch leaves affects not only gypsy moth fitness but also their innate immune status which might alter the potential resistance of insects against infections and/or parasitoids. PMID:25816371

  19. Leaf Surface Lipophilic Compounds as One of the Factors of Silver Birch Chemical Defense against Larvae of Gypsy Moth

    PubMed Central

    Martemyanov, Vyacheslav V.; Pavlushin, Sergey V.; Dubovskiy, Ivan M.; Belousova, Irina A.; Yushkova, Yuliya V.; Morosov, Sergey V.; Chernyak, Elena I.; Glupov, Victor V.

    2015-01-01

    Plant chemical defense against herbivores is a complex process which involves a number of secondary compounds. It is known that the concentration of leaf surface lipophilic compounds (SLCs), particularly those of flavonoid aglycones are increased with the defoliation treatment of silver birch Betula pendula. In this study we investigated how the alteration of SLCs concentration in the food affects the fitness and innate immunity of the gypsy moth Lymantria dispar. We found that a low SLCs concentrations in consumed leaves led to a rapid larval development and increased females’ pupae weight (= fecundity) compared to larvae fed with leaves with high SLCs content. Inversely, increasing the compounds concentration in an artificial diet produced the reverse effects: decreases in both larval weight and larval survival. Low SLCs concentrations in tree leaves differently affected larval innate immunity parameters. For both sexes, total hemocytes count in the hemolymph increased, while the activity of plasma phenoloxidase decreased when larvae consume leaves with reduced content of SLCs. Our results clearly demonstrate that the concentration of SLCs in silver birch leaves affects not only gypsy moth fitness but also their innate immune status which might alter the potential resistance of insects against infections and/or parasitoids. PMID:25816371

  20. Leaf surface lipophilic compounds as one of the factors of silver birch chemical defense against larvae of gypsy moth.

    PubMed

    Martemyanov, Vyacheslav V; Pavlushin, Sergey V; Dubovskiy, Ivan M; Belousova, Irina A; Yushkova, Yuliya V; Morosov, Sergey V; Chernyak, Elena I; Glupov, Victor V

    2015-01-01

    Plant chemical defense against herbivores is a complex process which involves a number of secondary compounds. It is known that the concentration of leaf surface lipophilic compounds (SLCs), particularly those of flavonoid aglycones are increased with the defoliation treatment of silver birch Betula pendula. In this study we investigated how the alteration of SLCs concentration in the food affects the fitness and innate immunity of the gypsy moth Lymantria dispar. We found that a low SLCs concentrations in consumed leaves led to a rapid larval development and increased females' pupae weight (= fecundity) compared to larvae fed with leaves with high SLCs content. Inversely, increasing the compounds concentration in an artificial diet produced the reverse effects: decreases in both larval weight and larval survival. Low SLCs concentrations in tree leaves differently affected larval innate immunity parameters. For both sexes, total hemocytes count in the hemolymph increased, while the activity of plasma phenoloxidase decreased when larvae consume leaves with reduced content of SLCs. Our results clearly demonstrate that the concentration of SLCs in silver birch leaves affects not only gypsy moth fitness but also their innate immune status which might alter the potential resistance of insects against infections and/or parasitoids.

  1. Subchronic atrazine exposure changes defensive behaviour profile and disrupts brain acetylcholinesterase activity of zebrafish.

    PubMed

    Schmidel, Ademir J; Assmann, Karla L; Werlang, Chariane C; Bertoncello, Kanandra T; Francescon, Francini; Rambo, Cassiano L; Beltrame, Gabriela M; Calegari, Daiane; Batista, Cibele B; Blaser, Rachel E; Roman Júnior, Walter A; Conterato, Greicy M M; Piato, Angelo L; Zanatta, Leila; Magro, Jacir Dal; Rosemberg, Denis B

    2014-01-01

    Animal behaviour is the interaction between environment and an individual organism, which also can be influenced by its neighbours. Variations in environmental conditions, as those caused by contaminants, may lead to neurochemical impairments altering the pattern of the behavioural repertoire of the species. Atrazine (ATZ) is an herbicide widely used in agriculture that is frequently detected in surface water, affecting non-target species. The zebrafish is a valuable model organism to assess behavioural and neurochemical effects of different contaminants since it presents a robust behavioural repertoire and also all major neurotransmitter systems described for mammalian species. The goal of this study was to evaluate the effects of subchronic ATZ exposure in defensive behaviours of zebrafish (shoaling, thigmotaxis, and depth preference) using the split depth tank. Furthermore, to investigate a putative role of cholinergic signalling on ATZ-mediated effects, we tested whether this herbicide alters acetylcholinesterase (AChE) activity in brain and muscle preparations. Fish were exposed to ATZ for 14days and the following groups were tested: control (0.2% acetone) and ATZ (10 and 1000μg/L). The behaviour of four animals in the same tank was recorded for 6min and biological samples were prepared. Our results showed that 1000μg/L ATZ significantly increased the inter-fish distance, as well as the nearest and farthest neighbour distances. This group also presented an increase in the shoal area with decreased social interaction. No significant differences were detected for the number of animals in the shallow area, latency to enter the shallow and time spent in shallow and deep areas of the apparatus, but the ATZ 1000 group spent significantly more time near the walls. Although ATZ did not affect muscular AChE, it significantly reduced AChE activity in brain. Exposure to 10μg/L ATZ did not affect behaviour or AChE activity. These data suggest that ATZ impairs defensive

  2. 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. PMID:27471515

  3. 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.

  4. 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

  5. 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.

  6. Inorganic chemically active adsorbents (ICAAs)

    SciTech Connect

    Ally, M.R.; Tavlarides, L.

    1997-10-01

    Oak Ridge National Laboratory (ORNL) researchers are developing a technology that combines metal chelation extraction technology and synthesis chemistry. They begin with a ceramic substrate such as alumina, titanium oxide or silica gel because they provide high surface area, high mechanical strength, and radiolytic stability. One preparation method involves silylation to hydrophobize the surface, followed by chemisorption of a suitable chelation agent using vapor deposition. Another route attaches newly designed chelating agents through covalent bonding by the use of coupling agents. These approaches provide stable and selective, inorganic chemically active adsorbents (ICAAs) tailored for removal of metals. The technology has the following advantages over ion exchange: (1) higher mechanical strength, (2) higher resistance to radiation fields, (3) higher selectivity for the desired metal ion, (4) no cation exchange, (5) reduced or no interference from accompanying anions, (6) faster kinetics, and (7) easy and selective regeneration. Target waste streams include metal-containing groundwater/process wastewater at ORNL`s Y-12 Plant (multiple metals), Savannah River Site (SRS), Rocky Flats (multiple metals), and Hanford; aqueous mixed wastes at Idaho National Engineering Laboratory (INEL); and scrubber water generated at SRS and INEL. Focus Areas that will benefit from this research include Mixed Waste, and Subsurface Contaminants.

  7. Two brominated cyclic dipeptides released by the coldwater marine sponge Geodia barretti act in synergy as chemical defense.

    PubMed

    Sjögren, Martin; Jonsson, Per R; Dahlström, Mia; Lundälv, Tomas; Burman, Robert; Göransson, Ulf; Bohlin, Lars

    2011-03-25

    The current work shows that two structurally similar cyclodipeptides, barettin (1) and 8,9-dihydrobarettin (2), produced by the coldwater marine sponge Geodia barretti Bowerbank act in synergy to deter larvae of surface settlers and may also be involved in defense against grazers. Previously, 1 and 2 were demonstrated to bind specifically to serotonergic 5-HT receptors. It may be suggested that chemical defense in G. barretti involves a synergistic action where one of the molecular targets is a 5-HT receptor. A mixture of 1 and 2 lowered the EC(50) of larval settlement as compared to the calculated theoretical additive effect of the two compounds. Moreover, an in situ sampling at 120 m depth using a remotely operated vehicle revealed that the sponge releases these two compounds to the ambient water. Thus, it is suggested that the synergistic action of 1 and 2 may benefit the sponge by reducing the expenditure of continuous production and release of its chemical defense substances. Furthermore, a synergistic action between structurally closely related compounds produced by the same bioenzymatic machinery ought to be the most energy effective for the organism and, thus, is more common than synergy between structurally indistinct compounds.

  8. 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.

  9. Discrimination of Arabidopsis PAD4 activities in defense against green peach aphid and pathogens.

    PubMed

    Louis, Joe; Gobbato, Enrico; Mondal, Hossain A; Feys, Bart J; Parker, Jane E; Shah, Jyoti

    2012-04-01

    The Arabidopsis (Arabidopsis thaliana) lipase-like protein PHYTOALEXIN DEFICIENT4 (PAD4) is essential for defense against green peach aphid (GPA; Myzus persicae) and the pathogens Pseudomonas syringae and Hyaloperonospora arabidopsidis. In basal resistance to virulent strains of P. syringae and H. arabidopsidis, PAD4 functions together with its interacting partner ENHANCED DISEASE SUSCEPTIBILITY1 (EDS1) to promote salicylic acid (SA)-dependent and SA-independent defenses. By contrast, dissociated forms of PAD4 and EDS1 signal effector-triggered immunity to avirulent strains of these pathogens. PAD4-controlled defense against GPA requires neither EDS1 nor SA. Here, we show that resistance to GPA is unaltered in an eds1 salicylic acid induction deficient2 (sid2) double mutant, indicating that redundancy between EDS1 and SID2-dependent SA, previously reported for effector-triggered immunity conditioned by certain nucleotide-binding-leucine-rich repeat receptors, does not explain the dispensability of EDS1 and SID2 in defense against GPA. Mutation of a conserved serine (S118) in the predicted lipase catalytic triad of PAD4 abolished PAD4-conditioned antibiosis and deterrence against GPA feeding, but S118 was dispensable for deterring GPA settling and promoting senescence in GPA-infested plants as well as for pathogen resistance. These results highlight distinct molecular activities of PAD4 determining particular aspects of defense against aphids and pathogens.

  10. Structural and chemical insect defenses in calcium oxalate defective mutants of Medicago truncatula

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Plant structures can act as defense against herbivorous insects, causing them to avoid feeding on a given plant or tissue. Mineral crystals of calcium oxalate in leaves of Medicago truncatula Gaertn. are effective deterrents of lepidopteran feeding, and they inhibit conversion of leaves into insect ...

  11. Ink from longfin inshore squid, Doryteuthis pealeii, as a chemical and visual defense against two predatory fishes, summer flounder, Paralichthys dentatus, and sea catfish, Ariopsis felis.

    PubMed

    Derby, Charles D; Tottempudi, Mihika; Love-Chezem, Tiffany; Wolfe, Lanna S

    2013-12-01

    Chemical and visual defenses are used by many organisms to avoid being approached or eaten by predators. An example is inking molluscs-including gastropods such as sea hares and cephalopods such as squid, cuttlefish, and octopus-which release a colored ink upon approach or attack. Previous work showed that ink can protect molluscs through a combination of chemical, visual, and other effects. In this study, we examined the effects of ink from longfin inshore squid, Doryteuthis pealeii, on the behavior of two species of predatory fishes, summer flounder, Paralichthys dentatus, and sea catfish, Ariopsis felis. Using a cloud assay, we found that ink from longfin inshore squid affected the approach phase of predation by summer flounder, primarily through its visual effects. Using a food assay, we found that the ink affected the consummatory and ingestive phase of predation of both sea catfish and summer flounder, through the ink's chemical properties. Fractionation of ink showed that most of its deterrent chemical activity is associated with melanin granules, suggesting that either compounds adhering to these granules or melanin itself are the most biologically active. This work provides the basis for a comparative approach to identify deterrent molecules from inking cephalopods and to examine neural mechanisms whereby these chemicals affect behavior of fish, using the sea catfish as a chemosensory model.

  12. Secondary Defense Chemicals in Milkweed Reduce Parasite Infection in Monarch Butterflies, Danaus plexippus.

    PubMed

    Gowler, Camden D; Leon, Kristoffer E; Hunter, Mark D; de Roode, Jacobus C

    2015-06-01

    In tri-trophic systems, herbivores may benefit from their host plants in fighting parasitic infections. Plants can provide parasite resistance in two contrasting ways: either directly, by interfering with the parasite, or indirectly, by increasing herbivore immunity or health. In monarch butterflies, the larval diet of milkweed strongly influences the fitness of a common protozoan parasite. Toxic secondary plant chemicals known as cardenolides correlate strongly with parasite resistance of the host, with greater cardenolide concentrations in the larval diet leading to lower parasite growth. However, milkweed cardenolides may covary with other indices of plant quality including nutrients, and a direct experimental link between cardenolides and parasite performance has not been established. To determine if the anti-parasitic activity of milkweeds is indeed due to secondary chemicals, as opposed to nutrition, we supplemented the diet of infected and uninfected monarch larvae with milkweed latex, which contains cardenolides but no nutrients. Across three experiments, increased dietary cardenolide concentrations reduced parasite growth in infected monarchs, which consequently had longer lifespans. However, uninfected monarchs showed no differences in lifespan across treatments, confirming that cardenolide-containing latex does not increase general health. Our results suggest that cardenolides are a driving force behind plant-derived resistance in this system. PMID:25953502

  13. Secondary Defense Chemicals in Milkweed Reduce Parasite Infection in Monarch Butterflies, Danaus plexippus.

    PubMed

    Gowler, Camden D; Leon, Kristoffer E; Hunter, Mark D; de Roode, Jacobus C

    2015-06-01

    In tri-trophic systems, herbivores may benefit from their host plants in fighting parasitic infections. Plants can provide parasite resistance in two contrasting ways: either directly, by interfering with the parasite, or indirectly, by increasing herbivore immunity or health. In monarch butterflies, the larval diet of milkweed strongly influences the fitness of a common protozoan parasite. Toxic secondary plant chemicals known as cardenolides correlate strongly with parasite resistance of the host, with greater cardenolide concentrations in the larval diet leading to lower parasite growth. However, milkweed cardenolides may covary with other indices of plant quality including nutrients, and a direct experimental link between cardenolides and parasite performance has not been established. To determine if the anti-parasitic activity of milkweeds is indeed due to secondary chemicals, as opposed to nutrition, we supplemented the diet of infected and uninfected monarch larvae with milkweed latex, which contains cardenolides but no nutrients. Across three experiments, increased dietary cardenolide concentrations reduced parasite growth in infected monarchs, which consequently had longer lifespans. However, uninfected monarchs showed no differences in lifespan across treatments, confirming that cardenolide-containing latex does not increase general health. Our results suggest that cardenolides are a driving force behind plant-derived resistance in this system.

  14. 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

  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. Variability in chemical defense across a shallow to mesophotic depth gradient in the Caribbean sponge Plakortis angulospiculatus

    NASA Astrophysics Data System (ADS)

    Slattery, Marc; Gochfeld, Deborah J.; Diaz, M. Cristina; Thacker, Robert W.; Lesser, Michael P.

    2016-03-01

    The transition between shallow and mesophotic coral reef communities in the tropics is characterized by a significant gradient in abiotic and biotic conditions that could result in potential trade-offs in energy allocation. The mesophotic reefs in the Bahamas and the Cayman Islands have a rich sponge fauna with significantly greater percent cover of sponges than in their respective shallow reef communities, but relatively low numbers of spongivores. Plakortis angulospiculatus, a common sponge species that spans the depth gradient from shallow to mesophotic reefs in the Caribbean, regenerates faster following predation and invests more energy in protein synthesis at mesophotic depths compared to shallow reef conspecifics. However, since P. angulospiculatus from mesophotic reefs typically contain lower concentrations of chemical feeding deterrents, they are not able to defend new tissue from predation as efficiently as conspecifics from shallow reefs. Nonetheless, following exposure to predators on shallow reefs, transplanted P. angulospiculatus from mesophotic depths developed chemical deterrence to predatory fishes. A survey of bioactive extracts indicated that a specific defensive metabolite, plakortide F, varied in concentration with depth, producing altered deterrence between shallow and mesophotic reef P. angulospiculatus. Different selective pressures in shallow and mesophotic habitats have resulted in phenotypic plasticity within this sponge species that is manifested in variable chemical defense and tissue regeneration at wound sites.

  17. Induced defenses change the chemical composition of pine seedlings and influence meal properties of the pine weevil Hylobius abietis.

    PubMed

    Lundborg, Lina; Fedderwitz, Frauke; Björklund, Niklas; Nordlander, Göran; Borg-Karlson, Anna-Karin

    2016-10-01

    The defense of conifers against phytophagous insects relies to a large extent on induced chemical defenses. However, it is not clear how induced changes in chemical composition influence the meal properties of phytophagous insects (and thus damage rates). The defense can be induced experimentally with methyl jasmonate (MeJA), which is a substance that is produced naturally when a plant is attacked. Here we used MeJA to investigate how the volatile contents of Scots pine (Pinus sylvestris L.) tissues influence the meal properties of the pine weevil (Hylobius abietis (L.)). Phloem and needles (both weevil target tissues) from MeJA-treated and control seedlings were extracted by n-hexane and analyzed by two-dimensional gas chromatography-mass spectrometry (2D GC-MS). The feeding of pine weevils on MeJA-treated and control seedlings were video-recorded to determine meal properties. Multivariate statistical analyses showed that phloem and needle contents of MeJA-treated seedlings had different volatile compositions compared to control seedlings. Levels of the pine weevil attractant (+)-α-pinene were particularly high in phloem of control seedlings with feeding damage. The antifeedant substance 2-phenylethanol occurred at higher levels in the phloem of MeJA-treated than in control seedlings. Accordingly, pine weevils fed slower and had shorter meals on MeJA-seedlings. The chemical compositions of phloem and needle tissues were clearly different in control seedlings but not in the MeJA-treated seedlings. Consequently, meal durations of mixed meals, i.e. both needles and phloem, were longer than phloem meals on control seedlings, while meal durations on MeJA seedlings did not differ between these meal contents. The meal duration influences the risk of girdling and plant death. Thus our results suggest a mechanism by which MeJA treatment may protect conifer seedlings against pine weevils. PMID:27417987

  18. [Systematically induced effects of Tetranychus cinnabarinus infestation on chemical defense in Zea mays inbred lines].

    PubMed

    Zhu, Yu-xi; Yang, Qun-fang; Huang, Yu-bi; Li, Qing

    2015-09-01

    In the present study, we investigated the systematically induced production of defense-related compounds, including DIMBOA, total phenol, trypsin inhibitors (TI) and chymotrypsin inhibitor (CI), by Tetranychus cinnabarinus infestation in Zea mays. The first leaves of two corn in-bred line seedlings, the mite-tolerant line ' H1014168' and the mite-sensitive line 'H1014591', were sucked by T. cinnabarinus adult female for seven days, and then the contents of DIMBOA, total phenol, TI and CI were measured in the second leaf and in the roots, respectively. Results showed that as compared to the unsucked control, all contents of DIMBOA, total phenol, TI and CI induced by T. cinnabarinus sucking were significantly higher in the second leaf of both inbred lines as well as in the roots of the mite-tolerant 'H1014168'. However, in the roots of 'H1014591', these defense compounds had different trends, where there was a higher induction of TI and a lower level of total phenol than that of the healthy control, while had almost no difference in DIMBOA and CI. These findings suggested that the infestation of T. cinnabarinus could systematically induce accumulation of defense-related compounds, and this effect was stronger in the mite-tolerant inbred line than in the mite-sensitive inbred line.

  19. Selection mosaic exerted by specialist and generalist herbivores on chemical and physical defense of Datura stramonium.

    PubMed

    Castillo, Guillermo; Cruz, Laura L; Tapia-López, Rosalinda; Olmedo-Vicente, Erika; Olmedo-Vicente, Eika; Carmona, Diego; Anaya-Lang, Ana Luisa; Fornoni, Juan; Andraca-Gómez, Guadalupe; Valverde, Pedro L; Núñez-Farfán, Juan

    2014-01-01

    Selection exerted by herbivores is a major force driving the evolution of plant defensive characters such as leaf trichomes or secondary metabolites. However, plant defense expression is highly variable among populations and identifying the sources of this variation remains a major challenge. Plant populations are often distributed across broad geographic ranges and are exposed to different herbivore communities, ranging from generalists (that feed on diverse plant species) to specialists (that feed on a restricted group of plants). We studied eight populations of the plant Datura stramonium usually eaten by specialist or generalist herbivores, in order to examine whether the pattern of phenotypic selection on secondary compounds (atropine and scopolamine) and a physical defense (trichome density) can explain geographic variation in these traits. Following co-evolutionary theory, we evaluated whether a more derived alkaloid (scopolamine) confers higher fitness benefits than its precursor (atropine), and whether this effect differs between specialist and generalist herbivores. Our results showed consistent directional selection in almost all populations and herbivores to reduce the concentration of atropine. The most derived alkaloid (scopolamine) was favored in only one of the populations, which is dominated by a generalist herbivore. In general, the patterns of selection support the existence of a selection mosaic and accounts for the positive correlation observed between atropine concentration and plant damage by herbivores recorded in previous studies. PMID:25051169

  20. Selection Mosaic Exerted by Specialist and Generalist Herbivores on Chemical and Physical Defense of Datura stramonium

    PubMed Central

    Castillo, Guillermo; Cruz, Laura L.; Tapia-López, Rosalinda; Olmedo-Vicente, Eika; Carmona, Diego; Anaya-Lang, Ana Luisa; Fornoni, Juan; Andraca-Gómez, Guadalupe; Valverde, Pedro L.; Núñez-Farfán, Juan

    2014-01-01

    Selection exerted by herbivores is a major force driving the evolution of plant defensive characters such as leaf trichomes or secondary metabolites. However, plant defense expression is highly variable among populations and identifying the sources of this variation remains a major challenge. Plant populations are often distributed across broad geographic ranges and are exposed to different herbivore communities, ranging from generalists (that feed on diverse plant species) to specialists (that feed on a restricted group of plants). We studied eight populations of the plant Datura stramonium usually eaten by specialist or generalist herbivores, in order to examine whether the pattern of phenotypic selection on secondary compounds (atropine and scopolamine) and a physical defense (trichome density) can explain geographic variation in these traits. Following co-evolutionary theory, we evaluated whether a more derived alkaloid (scopolamine) confers higher fitness benefits than its precursor (atropine), and whether this effect differs between specialist and generalist herbivores. Our results showed consistent directional selection in almost all populations and herbivores to reduce the concentration of atropine. The most derived alkaloid (scopolamine) was favored in only one of the populations, which is dominated by a generalist herbivore. In general, the patterns of selection support the existence of a selection mosaic and accounts for the positive correlation observed between atropine concentration and plant damage by herbivores recorded in previous studies. PMID:25051169

  1. Modulation of plasma membrane H+-ATPase activity differentially activates wound and pathogen defense responses in tomato plants.

    PubMed Central

    Schaller, A; Oecking, C

    1999-01-01

    Systemin is an important mediator of wound-induced defense gene activation in tomato plants, and it elicits a rapid alkalinization of the growth medium of cultured Lycopersicon peruvianum cells. A possible mechanistic link between proton fluxes across the plasma membrane and the induction of defense genes was investigated by modulating plasma membrane H+-ATPase activity. Inhibitors of H+-ATPase (erythrosin B, diethyl stilbestrol, and vanadate) were found to alkalinize the growth medium of L. peruvianum cell cultures and to induce wound response genes in whole tomato plants. Conversely, an activator of the H+-ATPase (fusicoccin) acidified the growth medium of L. peruvianum cell cultures and suppressed systemin-induced medium alkalinization. Likewise, in fusicoccin-treated tomato plants, the wound- and systemin-triggered accumulation of wound-responsive mRNAs was found to be suppressed. However, fusicoccin treatment of tomato plants led to the accumulation of salicylic acid and the expression of pathogenesis-related genes. Apparently, the wound and pathogen defense signaling pathways are differentially regulated by changes in the proton electrochemical gradient across the plasma membrane. In addition, alkalinization of the L. peruvianum cell culture medium was found to depend on the influx of Ca2+ and the activity of a protein kinase. Reversible protein phosphorylation was also shown to be involved in the induction of wound response genes. The plasma membrane H+-ATPase as a possible target of a Ca2+-activated protein kinase and its role in defense signaling are discussed. PMID:9927643

  2. Propolis volatile compounds: chemical diversity and biological activity: a review

    PubMed Central

    2014-01-01

    Propolis is a sticky material collected by bees from plants, and used in the hive as building material and defensive substance. It has been popular as a remedy in Europe since ancient times. Nowadays, propolis use in over-the-counter preparations, “bio”-cosmetics and functional foods, etc., increases. Volatile compounds are found in low concentrations in propolis, but their aroma and significant biological activity make them important for propolis characterisation. Propolis is a plant-derived product: its chemical composition depends on the local flora at the site of collection, thus it offers a significant chemical diversity. The role of propolis volatiles in identification of its plant origin is discussed. The available data about chemical composition of propolis volatiles from different geographic regions are reviewed, demonstrating significant chemical variability. The contribution of volatiles and their constituents to the biological activities of propolis is considered. Future perspectives in research on propolis volatiles are outlined, especially in studying activities other than antimicrobial. PMID:24812573

  3. Science Activities in Energy: Chemical Energy.

    ERIC Educational Resources Information Center

    Oak Ridge Associated Universities, TN.

    Presented is a science activities in energy package which includes 15 activities relating to chemical energy. Activities are simple, concrete experiments for fourth, fifth and sixth grades which illustrate principles and problems relating to energy. Each activity is outlined on a single card which is introduced by a question. A teacher's…

  4. Modulation of host defense peptide-mediated human mast cell activation by LPS

    PubMed Central

    Gupta, Kshitij; Subramanian, Hariharan; Ali, Hydar

    2016-01-01

    Human β-defensin3 (hBD3) and the cathelicidin LL-37 are host defense peptides (HDPs) that directly kill microbes and display immunomodulatory/wound healing properties via the activation of chemokine, formylpeptide and epidermal growth factor receptors on monocytes and epithelial cells. A C-terminal 14 amino acid hBD3 peptide with all Cys residues replaced with Ser (CHRG01) and an LL-37 peptide consisting of residues 17-29 (FK-13) display antimicrobial activity but lack immunomodulatory property. Surprisingly, we found that CHRG01 and FK-13 caused Ca2+ mobilization and degranulation in human mast cells via a novel G protein coupled receptor (GPCR) known as Mas-related gene-X2 (MrgX2). At local sites of bacterial infection, the negatively charged LPS likely interacts with cationic HDPs to inhibit their activity and thus providing a mechanism for pathogens to escape the host defense mechanisms. We found that LPS caused almost complete inhibition of hBD3 and LL-37-induced Ca2+ mobilization and mast cell degranulation. In contrast, it had no effect on CHRG01 and FK-13-induced mast cell responses. These findings suggest that HDP derivatives that kill microbes, harness mast cell’s host defense and wound healing properties via the activation of MrgX2 but are resistant to inhibition by LPS could be utilized for the treatment of antibiotic-resistant microbial infections. PMID:26511058

  5. 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.

  6. Activation of defense response pathways by OGs and Flg22 elicitors in Arabidopsis seedlings

    PubMed Central

    Denoux, Carine; Galletti, Roberta; Mammarella, Nicole; Gopalan, Suresh; Werck, Danièle; De Lorenzo, Giulia; Ferrari, Simone; Ausubel, Frederick M.; Dewdney, Julia

    2010-01-01

    We carried out transcriptional profiling analysis in 10 day-old Arabidopsis thaliana seedlings treated with oligogalacturonides (OGs), oligosaccharides derived from the plant cell wall, or the bacterial flagellin peptide Flg22, general elicitors of the basal defense response in plants. Although detected by different receptors, both OGs and Flg22 trigger a fast and transient response that is both similar and comprehensive, and characterized by activation of early stages of multiple defense signaling pathways, particularly JA-associated processes. However, the response to Flg22 is stronger in both the number of genes differentially expressed and the amplitude of change. The magnitude of induction of individual genes is in both cases dose dependent, but even at very high concentrations, OGs do not induce a response that is as comprehensive as that seen with Flg22. While high doses of either microbe-associated molecular pattern (MAMP) elicit a late response that includes activation of senescence processes, SA-dependent secretory pathway genes and PR1 expression are substantially induced only by Flg22. These results suggest a lower threshold for activation of early responses than for sustained or SA-mediated late defenses. Expression patterns of aminocyclopropane-carboxylate synthase genes also implicate ethylene biosynthesis in regulation of the late innate immune response. PMID:19825551

  7. Chemical Potentials and Activities: An Electrochemical Introduction.

    ERIC Educational Resources Information Center

    Wetzel, T. L.; And Others

    1986-01-01

    Describes a laboratory experiment which explores the effects of adding inert salts to electrolytic cells and demonstrates the difference between concentration and chemical activity. Examines chemical potentials as the driving force of reactions. Provides five examples of cell potential and concentration change. (JM)

  8. [Defense mechanism to prevent ectopic activation of pancreatic digestive enzymes under physiological conditions and its breakdown in acute pancreatitis].

    PubMed

    Kaku, Midori; Otsuko, Makoto

    2004-11-01

    Independent of the etiology, acute pancreatitis is associated with significant morbidity and the potential for mortality. In most patients, acute pancreatitis follows an uncomplicated or mild course. Recent studies in hereditary pancreatitis have clearly revealed that trypsin is the key enzyme at the onset of pancreatitis. However, there are several defense mechanisms to prevent ectopic activation of trypsin under physiological conditions. If the defense mechanisms failed or activation of trypsin occurred over defense ability, trypsin would activate other digestive enzymes and self-digestion of the pancreas would occur.

  9. Calmodulin-binding transcription activator (CAMTA) 3 mediates biotic defense responses in Arabidopsis.

    PubMed

    Galon, Yael; Nave, Roy; Boyce, Joy M; Nachmias, Dikla; Knight, Marc R; Fromm, Hillel

    2008-03-19

    Calmodulin-binding transcription activator (CAMTA) 3 (also called SR1) is a calmodulin-binding transcription factor in Arabidopsis. Two homozygous T-DNA insertion mutants (camta3-1, camta3-2) showed enhanced spontaneous lesions. Transcriptome analysis of both mutants revealed 6 genes with attenuated expression and 99 genes with elevated expression. Of the latter, 32 genes are related to defense against pathogens (e.g. WRKY33, PR1 and chitinase). Propagation of a virulent strain of the bacterial pathogen Pseudomonas syringae and the fungal pathogen Botrytis cinerea were attenuated in both mutants. Moreover, both mutants accumulated high levels of H2O2. We suggest that CAMTA3 regulates the expression of a set of genes involved in biotic defense responses.

  10. Influence of Genotype, Environment, and Gypsy Moth Herbivory on Local and Systemic Chemical Defenses in Trembling Aspen (Populus tremuloides).

    PubMed

    Rubert-Nason, Kennedy F; Couture, John J; Major, Ian T; Constabel, C Peter; Lindroth, Richard L

    2015-07-01

    Numerous studies have explored the impacts of intraspecific genetic variation and environment on the induction of plant chemical defenses by herbivory. Relatively few, however, have considered how those factors affect within-plant distribution of induced defenses. This work examined the impacts of plant genotype and soil nutrients on the local and systemic phytochemical responses of trembling aspen (Populus tremuloides) to defoliation by gypsy moth (Lymantria dispar). We deployed larvae onto foliage on individual tree branches for 15 days and then measured chemistry in leaves from: 1) branches receiving damage, 2) undamaged branches of insect-damaged trees, and 3) branches of undamaged control trees. The relationship between post-herbivory phytochemical variation and insect performance also was examined. Plant genotype, soil nutrients, and damage all influenced phytochemistry, with genotype and soil nutrients being stronger determinants than damage. Generally, insect damage decreased foliar nitrogen, increased levels of salicinoids and condensed tannins, but had little effect on levels of a Kunitz trypsin inhibitor, TI3. The largest damage-mediated tannin increases occurred in leaves on branches receiving damage, whereas the largest salicinoid increases occurred in leaves of adjacent, undamaged branches. Foliar nitrogen and the salicinoid tremulacin had the strongest positive and negative relationships, respectively, with insect growth. Overall, plant genetics and environment concomitantly influenced both local and systemic phytochemical responses to herbivory. These findings suggest that herbivory can contribute to phytochemical heterogeneity in aspen foliage, which may in turn influence future patterns of herbivory and nutrient cycling over larger spatial scales.

  11. Influence of Genotype, Environment, and Gypsy Moth Herbivory on Local and Systemic Chemical Defenses in Trembling Aspen (Populus tremuloides).

    PubMed

    Rubert-Nason, Kennedy F; Couture, John J; Major, Ian T; Constabel, C Peter; Lindroth, Richard L

    2015-07-01

    Numerous studies have explored the impacts of intraspecific genetic variation and environment on the induction of plant chemical defenses by herbivory. Relatively few, however, have considered how those factors affect within-plant distribution of induced defenses. This work examined the impacts of plant genotype and soil nutrients on the local and systemic phytochemical responses of trembling aspen (Populus tremuloides) to defoliation by gypsy moth (Lymantria dispar). We deployed larvae onto foliage on individual tree branches for 15 days and then measured chemistry in leaves from: 1) branches receiving damage, 2) undamaged branches of insect-damaged trees, and 3) branches of undamaged control trees. The relationship between post-herbivory phytochemical variation and insect performance also was examined. Plant genotype, soil nutrients, and damage all influenced phytochemistry, with genotype and soil nutrients being stronger determinants than damage. Generally, insect damage decreased foliar nitrogen, increased levels of salicinoids and condensed tannins, but had little effect on levels of a Kunitz trypsin inhibitor, TI3. The largest damage-mediated tannin increases occurred in leaves on branches receiving damage, whereas the largest salicinoid increases occurred in leaves of adjacent, undamaged branches. Foliar nitrogen and the salicinoid tremulacin had the strongest positive and negative relationships, respectively, with insect growth. Overall, plant genetics and environment concomitantly influenced both local and systemic phytochemical responses to herbivory. These findings suggest that herbivory can contribute to phytochemical heterogeneity in aspen foliage, which may in turn influence future patterns of herbivory and nutrient cycling over larger spatial scales. PMID:26099738

  12. Non-canonical inflammasome activation of caspase-4/caspase-11 mediates epithelial defenses against enteric bacterial pathogens

    PubMed Central

    Knodler, Leigh A.; Crowley, Shauna M.; Sham, Ho Pan; Yang, Hyungjun; Wrande, Marie; Ma, Caixia; Ernst, Robert K.; Steele-Mortimer, Olivia; Celli, Jean; Vallance, Bruce A.

    2014-01-01

    Summary Inflammasome-mediated host defenses have been extensively studied in innate immune cells. Whether inflammasomes function for innate defense in intestinal epithelial cells, which represent the first line of defense against enteric pathogens, remains unknown. We observed enhanced Salmonella enterica serovar Typhimurium colonization in the intestinal epithelium of caspase-11 deficient mice, but not at systemic sites. In polarized epithelial monolayers, siRNA-mediated depletion of caspase-4, a human orthologue of caspase-11, also led to increased bacterial colonization. Decreased rates of pyroptotic cell death, a host defense mechanism that extrudes S. Typhimurium infected cells from the polarized epithelium, accounted for increased pathogen burdens. The caspase-4 inflammasome also governs activation of the proinflammatory cytokine, interleukin (IL)-18, in response to intracellular (S. Typhimurium) and extracellular (enteropathogenic Escherichia coli) enteric pathogens, via intracellular LPS sensing. Therefore an epithelial cell intrinsic non-canonical inflammasome plays a critical role in antimicrobial defense at the intestinal mucosal surface. PMID:25121752

  13. Dual ligand/receptor interactions activate urothelial defenses against uropathogenic E. coli.

    PubMed

    Liu, Yan; Mémet, Sylvie; Saban, Ricardo; Kong, Xiangpeng; Aprikian, Pavel; Sokurenko, Evgeni; Sun, Tung-Tien; Wu, Xue-Ru

    2015-11-09

    During urinary tract infection (UTI), the second most common bacterial infection, dynamic interactions take place between uropathogenic E. coli (UPEC) and host urothelial cells. While significant strides have been made in the identification of the virulence factors of UPEC, our understanding of how the urothelial cells mobilize innate defenses against the invading UPEC remains rudimentary. Here we show that mouse urothelium responds to the adhesion of type 1-fimbriated UPEC by rapidly activating the canonical NF-κB selectively in terminally differentiated, superficial (umbrella) cells. This activation depends on a dual ligand/receptor system, one between FimH adhesin and uroplakin Ia and another between lipopolysaccharide and Toll-like receptor 4. When activated, all the nuclei (up to 11) of a multinucleated umbrella cell are affected, leading to significant amplification of proinflammatory signals. Intermediate and basal cells of the urothelium undergo NF-κB activation only if the umbrella cells are detached or if the UPEC persistently express type 1-fimbriae. Inhibition of NF-κB prevents the urothelium from clearing the intracellular bacterial communities, leading to prolonged bladder colonization by UPEC. Based on these data, we propose a model of dual ligand/receptor system in innate urothelial defenses against UPEC.

  14. Regulation of a chemical defense against herbivory produced by symbiotic fungi in grass plants.

    PubMed

    Zhang, Dong-Xiu; Nagabhyru, Padmaja; Schardl, Christopher L

    2009-06-01

    Neotyphodium uncinatum and Neotyphodium siegelii are fungal symbionts (endophytes) of meadow fescue (MF; Lolium pratense), which they protect from insects by producing loline alkaloids. High levels of lolines are produced following insect damage or mock herbivory (clipping). Although loline alkaloid levels were greatly elevated in regrowth after clipping, loline-alkaloid biosynthesis (LOL) gene expression in regrowth and basal tissues was similar to unclipped controls. The dramatic increase of lolines in regrowth reflected the much higher concentrations in young (center) versus older (outer) leaf blades, so LOL gene expression was compared in these tissues. In MF-N. siegelii, LOL gene expression was similar in younger and older leaf blades, whereas expression of N. uncinatum LOL genes and some associated biosynthesis genes was higher in younger than older leaf blades. Because lolines are derived from amino acids that are mobilized to new growth, we tested the amino acid levels in center and outer leaf blades. Younger leaf blades of aposymbiotic plants (no endophyte present) had significantly higher levels of asparagine and sometimes glutamine compared to older leaf blades. The amino acid levels were much lower in MF-N. siegelii and MF-N. uncinatum compared to aposymbiotic plants and MF with Epichloë festucae (a closely related symbiont), which lacked lolines. We conclude that loline alkaloid production in young tissue depleted these amino acid pools and was apparently regulated by availability of the amino acid substrates. As a result, lolines maximally protect young host tissues in a fashion similar to endogenous plant metabolites that conform to optimal defense theory. PMID:19403726

  15. Interactions between Bacteria And Aspen Defense Chemicals at the Phyllosphere - Herbivore Interface.

    PubMed

    Mason, Charles J; Lowe-Power, Tiffany M; Rubert-Nason, Kennedy F; Lindroth, Richard L; Raffa, Kenneth F

    2016-03-01

    Plant- and insect-associated microorganisms encounter a diversity of allelochemicals, and require mechanisms for contending with these often deleterious and broadly-acting compounds. Trembling aspen, Populus tremuloides, contains two principal groups of defenses, phenolic glycosides (salicinoids) and condensed tannins, which differentially affect the folivorous gypsy moth, Lymantria dispar, and its gut symbionts. The bacteria genus Acinetobacter is frequently associated with both aspen foliage and gypsy moth consuming that tissue, and one isolate, Acinetobacter sp. R7-1, previously has been shown to metabolize phenolic glycosides. In this study, we aimed to characterize further interactions between this Acinetobacter isolate and aspen secondary metabolites. We assessed bacterial carbon utilization and growth in response to different concentrations of phenolic glycosides and condensed tannins. We also tested if enzyme inhibitors reduce bacterial growth and catabolism of phenolic glycosides. Acinetobacter sp. R7-1 utilized condensed tannins but not phenolic glycosides or glucose as carbon sources. Growth in nutrient-rich medium was increased by condensed tannins, but reduced by phenolic glycosides. Addition of the P450 enzyme inhibitor piperonyl butoxide increased the effects of phenolic glycosides on Acinetobacter sp. R7-1. In contrast, the esterase inhibitor S,S,S,-tributyl-phosphorotrithioate did not affect phenolic glycoside inhibition of bacterial growth. Degradation of phenolic glycosides by Acinetobacter sp. R7-1 appears to alleviate the cytotoxicity of these compounds, rather than provide an energy source. Our results further suggest this bacterium utilizes additional, complementary mechanisms to degrade antimicrobial phytochemicals. Collectively, these results provide insight into mechanisms by which microorganisms contend with their environment within the context of plant-herbivore interactions.

  16. Interactions between Bacteria And Aspen Defense Chemicals at the Phyllosphere - Herbivore Interface.

    PubMed

    Mason, Charles J; Lowe-Power, Tiffany M; Rubert-Nason, Kennedy F; Lindroth, Richard L; Raffa, Kenneth F

    2016-03-01

    Plant- and insect-associated microorganisms encounter a diversity of allelochemicals, and require mechanisms for contending with these often deleterious and broadly-acting compounds. Trembling aspen, Populus tremuloides, contains two principal groups of defenses, phenolic glycosides (salicinoids) and condensed tannins, which differentially affect the folivorous gypsy moth, Lymantria dispar, and its gut symbionts. The bacteria genus Acinetobacter is frequently associated with both aspen foliage and gypsy moth consuming that tissue, and one isolate, Acinetobacter sp. R7-1, previously has been shown to metabolize phenolic glycosides. In this study, we aimed to characterize further interactions between this Acinetobacter isolate and aspen secondary metabolites. We assessed bacterial carbon utilization and growth in response to different concentrations of phenolic glycosides and condensed tannins. We also tested if enzyme inhibitors reduce bacterial growth and catabolism of phenolic glycosides. Acinetobacter sp. R7-1 utilized condensed tannins but not phenolic glycosides or glucose as carbon sources. Growth in nutrient-rich medium was increased by condensed tannins, but reduced by phenolic glycosides. Addition of the P450 enzyme inhibitor piperonyl butoxide increased the effects of phenolic glycosides on Acinetobacter sp. R7-1. In contrast, the esterase inhibitor S,S,S,-tributyl-phosphorotrithioate did not affect phenolic glycoside inhibition of bacterial growth. Degradation of phenolic glycosides by Acinetobacter sp. R7-1 appears to alleviate the cytotoxicity of these compounds, rather than provide an energy source. Our results further suggest this bacterium utilizes additional, complementary mechanisms to degrade antimicrobial phytochemicals. Collectively, these results provide insight into mechanisms by which microorganisms contend with their environment within the context of plant-herbivore interactions. PMID:26961755

  17. Regulation of a chemical defense against herbivory produced by symbiotic fungi in grass plants.

    PubMed

    Zhang, Dong-Xiu; Nagabhyru, Padmaja; Schardl, Christopher L

    2009-06-01

    Neotyphodium uncinatum and Neotyphodium siegelii are fungal symbionts (endophytes) of meadow fescue (MF; Lolium pratense), which they protect from insects by producing loline alkaloids. High levels of lolines are produced following insect damage or mock herbivory (clipping). Although loline alkaloid levels were greatly elevated in regrowth after clipping, loline-alkaloid biosynthesis (LOL) gene expression in regrowth and basal tissues was similar to unclipped controls. The dramatic increase of lolines in regrowth reflected the much higher concentrations in young (center) versus older (outer) leaf blades, so LOL gene expression was compared in these tissues. In MF-N. siegelii, LOL gene expression was similar in younger and older leaf blades, whereas expression of N. uncinatum LOL genes and some associated biosynthesis genes was higher in younger than older leaf blades. Because lolines are derived from amino acids that are mobilized to new growth, we tested the amino acid levels in center and outer leaf blades. Younger leaf blades of aposymbiotic plants (no endophyte present) had significantly higher levels of asparagine and sometimes glutamine compared to older leaf blades. The amino acid levels were much lower in MF-N. siegelii and MF-N. uncinatum compared to aposymbiotic plants and MF with Epichloë festucae (a closely related symbiont), which lacked lolines. We conclude that loline alkaloid production in young tissue depleted these amino acid pools and was apparently regulated by availability of the amino acid substrates. As a result, lolines maximally protect young host tissues in a fashion similar to endogenous plant metabolites that conform to optimal defense theory.

  18. 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

  19. Activation of defense mechanism in wheat by polyphenol oxidase from aphid saliva.

    PubMed

    Ma, Rui; Chen, Ju-Lian; Cheng, Deng-Fa; Sun, Jing-Rui

    2010-02-24

    The saliva of two cereal aphids, Sitobion avenae and Schizaphis graminum in third-instar nymphs, was collected after 24 h of feeding by 30 aphids, separately, on artificial diet sachets, and the salivary enzymes were determined. The result showed that polyphenol oxidase (PPO) existed in the saliva of both aphid species, and the enzymatic activities were 6.2 x 10(-3) U/g for S. avenae and 2.37 x 10(-1) U/g for S. graminum, revealing a 38-fold higher activity in the saliva of S. graminum than in the saliva of S. avenae. It was speculated that the higher PPO activity in S. graminum saliva was a contributing factor to the light yellow spot left on the feeding site of the wheat leaf by S. graminum; no such spot was left by S. avenae. After treatment of a wheat seedling with the saliva of S. avenae and S. graminum and PPO at the concentration of aphid saliva, transcript profiling data showed that aphid saliva and PPO significantly induced expression of the genes aos and fps. Because genes aos and fps encode the key enzymes in the defense signal pathways jasmonic acid and terpene signal pathways, respectively, it was deduced that PPO from aphid saliva, as the main elicitor, triggers an appropriate defense response in wheat through jasmonic acid and terpene signal pathways. PMID:20112908

  20. Activation of Molecular Signatures for Antimicrobial and Innate Defense Responses in Skin with Transglutaminase 1 Deficiency.

    PubMed

    Haneda, Takashi; Imai, Yasutomo; Uchiyama, Ryosuke; Jitsukawa, Orie; Yamanishi, Kiyofumi

    2016-01-01

    Mutations of the transglutaminase 1 gene (TGM1) are a major cause of autosomal recessive congenital ichthyoses (ARCIs) that are associated with defects in skin barrier structure and function. However, the molecular processes induced by the transglutaminase 1 deficiency are not fully understood. The aim of the present study was to uncover those processes by analysis of cutaneous molecular signatures. Gene expression profiles of wild-type and Tgm1-/-epidermis were assessed using microarrays. Gene ontology analysis of the data showed that genes for innate defense responses were up-regulated in Tgm1-/-epidermis. Based on that result, the induction of Il1b and antimicrobial peptide genes, S100a8, S100a9, Defb14, Camp, Slpi, Lcn2, Ccl20 and Wfdc12, was confirmed by quantitative real-time PCR. A protein array revealed that levels of IL-1β, G-CSF, GM-CSF, CXCL1, CXCL2, CXCL9 and CCL2 were increased in Tgm1-/-skin. Epidermal growth factor receptor (EGFR) ligand genes, Hbegf, Areg and Ereg, were activated in Tgm1-/-epidermis. Furthermore, the antimicrobial activity of an epidermal extract from Tgm1-/-mice was significantly increased against both Escherichia coli and Staphylococcus aureus. In the epidermis of ichthyosiform skins from patients with TGM1 mutations, S100A8/9 was strongly positive. The expression of those antimicrobial and defense response genes was also increased in the lesional skin of an ARCI patient with TGM1 mutations. These results suggest that the up-regulation of molecular signatures for antimicrobial and innate defense responses is characteristic of skin with a transglutaminase 1 deficiency, and this autonomous process might be induced to reinforce the defective barrier function of the skin. PMID:27442430

  1. Activation of Molecular Signatures for Antimicrobial and Innate Defense Responses in Skin with Transglutaminase 1 Deficiency

    PubMed Central

    Uchiyama, Ryosuke; Jitsukawa, Orie; Yamanishi, Kiyofumi

    2016-01-01

    Mutations of the transglutaminase 1 gene (TGM1) are a major cause of autosomal recessive congenital ichthyoses (ARCIs) that are associated with defects in skin barrier structure and function. However, the molecular processes induced by the transglutaminase 1 deficiency are not fully understood. The aim of the present study was to uncover those processes by analysis of cutaneous molecular signatures. Gene expression profiles of wild-type and Tgm1–/–epidermis were assessed using microarrays. Gene ontology analysis of the data showed that genes for innate defense responses were up-regulated in Tgm1–/–epidermis. Based on that result, the induction of Il1b and antimicrobial peptide genes, S100a8, S100a9, Defb14, Camp, Slpi, Lcn2, Ccl20 and Wfdc12, was confirmed by quantitative real-time PCR. A protein array revealed that levels of IL-1β, G-CSF, GM-CSF, CXCL1, CXCL2, CXCL9 and CCL2 were increased in Tgm1–/–skin. Epidermal growth factor receptor (EGFR) ligand genes, Hbegf, Areg and Ereg, were activated in Tgm1–/–epidermis. Furthermore, the antimicrobial activity of an epidermal extract from Tgm1–/–mice was significantly increased against both Escherichia coli and Staphylococcus aureus. In the epidermis of ichthyosiform skins from patients with TGM1 mutations, S100A8/9 was strongly positive. The expression of those antimicrobial and defense response genes was also increased in the lesional skin of an ARCI patient with TGM1 mutations. These results suggest that the up-regulation of molecular signatures for antimicrobial and innate defense responses is characteristic of skin with a transglutaminase 1 deficiency, and this autonomous process might be induced to reinforce the defective barrier function of the skin. PMID:27442430

  2. Secondary Metabolome Variability and Inducible Chemical Defenses in the Mediterranean Sponge Aplysina cavernicola.

    PubMed

    Reverter, M; Perez, T; Ereskovsky, A V; Banaigs, B

    2016-01-01

    Secondary metabolites play a crucial role in marine invertebrate chemical ecology. Thus, it is of great importance to understand factors regulating their production and sources of variability. This work aimed to study the variability of the bromotyrosine derivatives in the Mediterranean sponge Aplysina cavernicola, and also to better understand how biotic (reproductive state) and abiotic factors (seawater temperature) could partly explain this variability. Results showed that the A. cavernicola reproductive cycle has little effect on the variability of the sponges' secondary metabolism, whereas water temperature has a significant influence on the production level of secondary metabolites. Temporal variability analysis of the sponge methanolic extracts showed that bioactivity variability was related to the presence of the minor secondary metabolite dienone, which accounted for 50 % of the bioactivity observed. Further bioassays coupled to HPLC extract fractionation confirmed that dienone was the only compound from Aplysina alkaloids to display a strong bioactivity. Both dienone production and bioactivity showed a notable increase in October 2008, after a late-summer warming episode, indicating that A. cavernicola might be able to induce chemical changes to cope with environmental stressors.

  3. Activated coconut shell charcoal carbon using chemical-physical activation

    NASA Astrophysics Data System (ADS)

    Budi, Esmar; Umiatin, Nasbey, Hadi; Bintoro, Ridho Akbar; Wulandari, Futri; Erlina

    2016-02-01

    The use of activated carbon from natural material such as coconut shell charcoal as metal absorbance of the wastewater is a new trend. The activation of coconut shell charcoal carbon by using chemical-physical activation has been investigated. Coconut shell was pyrolized in kiln at temperature about 75 - 150 °C for about 6 hours in producing charcoal. The charcoal as the sample was shieved into milimeter sized granule particle and chemically activated by immersing in various concentration of HCl, H3PO4, KOH and NaOH solutions. The samples then was physically activated using horizontal furnace at 400°C for 1 hours in argon gas environment with flow rate of 200 kg/m3. The surface morphology and carbon content of activated carbon were characterized by using SEM/EDS. The result shows that the pores of activated carbon are openned wider as the chemical activator concentration is increased due to an excessive chemical attack. However, the pores tend to be closed as further increasing in chemical activator concentration due to carbon collapsing.

  4. Marine-terrestrial contrasts in the ecology of plant chemical defenses against herbivores.

    PubMed

    Hay, M E

    1991-11-01

    Small marine herbivores that live on the plants they consume often selectively eat seaweeds that are chemically defended from fishes. Their feeding is unaffected or stimulated by the plant metabolites that deter fishes, and these small herbivores dramatically reduce their susceptibility to predation by associating with host plants that are noxious to fishes. Ecological similarities between these small marine herbivores and numerous terrestrial insects suggest that herbivorous insects also may have evolved a preference for toxic plants because this diminishes their losses to predators, parasites and pathogens. Although marine and terrestrial plants and herbivores evolved in strikingly different environments, the ease of experimentation in some marine systems makes them ideal for addressing certain questions of fundamental importance to both terrestrial and marine workers.

  5. Palatability and chemical defense of Phragmites australis to the marsh periwinkle snail Littoraria irrorata.

    PubMed

    Hendricks, Lindsey G; Mossop, Hannah E; Kicklighter, Cynthia E

    2011-08-01

    Coastal marsh habitats are impacted by many disturbances, including habitat destruction, pollution, and the introduction of invasive species. The common reed, Phragmites australis, has been particularly invasive in the mesohaline regions of the Chesapeake Bay, but few studies have investigated its role in trophic interactions with North American marsh consumers. The marsh periwinkle snail Littoraria irrorata is a common grazer in marshes and grazes on the native grass Spartina alterniflora. Whether this snail grazes on Phragmites has not been addressed. We found Spartina leaves to be tougher than those of Phragmites, but despite this, snails consumed significantly more Spartina than Phragmites. Subsequent experiments demonstrated that Phragmites is chemically deterrent to snails by an unknown, moderately polar, compound. Further studies are required to more fully understand the interactions between Phragmites, herbivores, and Spartina, and how they may impact marsh ecosystems.

  6. Arabidopsis sigma factor binding proteins are activators of the WRKY33 transcription factor in plant defense.

    PubMed

    Lai, Zhibing; Li, Ying; Wang, Fei; Cheng, Yuan; Fan, Baofang; Yu, Jing-Quan; Chen, Zhixiang

    2011-10-01

    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.

  7. 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.

  8. [Features of brain oscillatory activity and cardiac defense in treatment arterial hypertensives].

    PubMed

    Aftanas, L I; Brak, I V; Gilinskaia, O M; Pavlov, S V; Reva, N V

    2014-01-01

    Stress reactivity of the motivational system of defense can be assessed with the aid the cardiac defense response (CDR) - the reaction of the cardiovascular system to unexpected aversive unconditioned stimulus. The main objective of the study was revealing putative contribution of oscillatory systems of the brain into central pathogenic mechanisms of enhanced blood pressure (BP) stress-reactivity in naive patients with arterial hypertension (AH) of the 1st-2nd degrees (n = 17) and healthy control (n = 19) subjects. Using dynamic registration "beat-by-beat" arterial pressure, and oscillatory activity related EEG (64 channels) is estimated using the event-related synchronization/desynchronization (ERD/ERS). Along with abnormally high blood pressure in patients with hypertension background set significantly lower concentrations of serotonin blood platelets and increased tonic activation of the left hemisphere, reflected in the asymmetric reduction of delta- (2-4 Hz) and theta-1 (4-6 Hz) power in the central and parietal cortex in the hemisphere CDR of the patients are characterized by hyperactivity both short- and long-latency components of blood pressure. According to the dynamic analysis of the concomitant EEG, long-latency BP components may be accounted by, among other mechanisms, weakening of the descending ("top-down") inhibitory control, hypothetically implemented with the high-frequency EEG alpha (10-12 Hz) oscillations from the medial central-parietal cortex of both hemispheres of the brain. PMID:25464727

  9. Expanding the 'enemy-free space' for oribatid mites: evidence for chemical defense of juvenile Archegozetes longisetosus against the rove beetle Stenus juno.

    PubMed

    Heethoff, Michael; Raspotnig, Günther

    2012-02-01

    Adult oribatid mites are thought to live functionally in 'enemy-free space' due to numerous morphological and chemical defensive strategies. Most juvenile oribatid mites, however, lack hardened cuticles and are thus thought to be under stronger predation pressure. On the other hand, the majority of oribatids have exocrine oil glands in all developmental stages, possibly rendering chemical defense the crucial survival strategy in juvenile Oribatida. We manipulated tritonymphs of the model oribatid mite Archegozetes longisetosus to completely discharge their oil glands and offered these chemically disarmed specimens to the polyphagous rove beetle Stenus juno. Disarmed specimens were easily consumed. By contrast, specimens with filled oil glands were significantly protected, being rejected by the beetles. This is the first direct evidence that oil gland secretions provide soft-bodied juvenile oribatids with chemical protection against large arthropod predators.

  10. Neural network pattern recognition of thermal-signature spectra for chemical defense

    NASA Astrophysics Data System (ADS)

    Carrieri, Arthur H.; Lim, Pascal I.

    1995-05-01

    We treat infrared patterns of absorption or emission by nerve and blister agent compounds (and simulants of this chemical group) as features for the training of neural networks to detect the compounds' liquid layers on the ground or their vapor plumes during evaporation by external heating. Training of a four-layer network architecture is composed of a backward-error-propagation algorithm and a gradient-descent paradigm. We conduct testing by feed-forwarding preprocessed spectra through the network in a scaled format consistent with the structure of the training-data-set representation. The best-performance weight matrix (spectral filter) evolved from final network training and testing with software simulation trials is electronically transferred to a set of eight artificial intelligence integrated circuits (ICs') in specific modular form (splitting of weight matrices). This form makes full use of all input-output IC nodes. This neural network computer serves an important real-time detection function when it is integrated into pre-and postprocessing data-handling units of a tactical prototype thermoluminescence sensor now under development at the Edgewood Research, Development, and Engineering Center.

  11. Disposal of defense spent fuel and HLW at the Idaho Chemical Processing Plant

    SciTech Connect

    Ermold, L.F.; Loo, H.H.; Klingler, R.D.; Herzog, J.D.; Knecht, D.A.

    1993-06-01

    Irradiated nuclear fuel has been reprocessed at the Idaho Chemical Processing Plant (ICPP) since 1953 to recover uranium-235 and krypton-85 for the US Department of Energy (DOE). The resulting acidic high-level radioactive waste (HLW) has been solidified to a calcine since 1963 and stored in stainless steel underground bins enclosed by concrete vaults. Several different types of unprocessed irradiated DOE-owned fuels are also in storage at the ICPP. In April, 1992, DOE announced that spent fuel would no longer be reprocessed to recover enriched uranium and called for a shutdown of the reprocessing facilities at the ICPP. A new Spent Fuel and HLW Technology Development program was subsequently initiated to develop technologies for immobilizing ICPP spent fuels and HLW for disposal, in accordance with the Nuclear Waste Policy Act. The Program elements include Systems Analysis, Graphite Fuel Disposal, Other Spent Fuel Disposal, Sodium-Bearing Liquid Waste Processing, Calcine Immobilization, and Metal Recycle/Waste Minimization. This paper presents an overview of the ICPP radioactive wastes and current spent fuels, with an emphasis on the description of HLW and spent fuels requiring repository disposal.

  12. Structural determinants of host defense peptides for antimicrobial activity and target cell selectivity.

    PubMed

    Takahashi, Daisuke; Shukla, Sanjeev K; Prakash, Om; Zhang, Guolong

    2010-09-01

    Antimicrobial host defense peptides (HDPs) are a critical component of the innate immunity with microbicidal, endotoxin-neutralizing, and immunostimulatory properties. HDPs kill bacteria primarily through non-specific membrane lysis, therefore with a less likelihood of provoking resistance. Extensive structure-activity relationship studies with a number of HDPs have revealed that net charge, amphipathicity, hydrophobicity, and structural propensity are among the most important physicochemical and structural parameters that dictate their ability to interact with and disrupt membranes. A delicate balance among these factors, rather than a mere alteration of a single factor, is critically important for HDPs to ensure the antimicrobial potency and target cell selectivity. With a better understanding of the structural determinants of HDPs for their membrane-lytic activities, it is expected that novel HDP-based antimicrobials with minimum toxicity to eukaryotic cells can be developed for resistant infections, which have become a global public health crisis.

  13. Effects of inhalation of organic chemical air contaminants on murine lung host defenses

    SciTech Connect

    Aranyi, C.; O'Shea, W.J.; Graham, J.A.; Miller, F.J.

    1986-05-01

    The potential health hazards of exposure to threshold limit value (TLV) concentrations of acetaldehyde, acrolein, propylene oxide, chloroform, methyl chloroform, carbon tetrachloride, allyl chloride, methylene chloride, ethylene trichloride, perchloroethylene, benzene, phenol, monochlorobenzene, and benzyl chloride, compounds which may be present in the ambient or work room atmosphere were investigated. The effects of single and multiple 3-hr inhalation exposures were evaluated in mice by monitoring changes in their susceptibility to experimentally induced streptococcus aerosol infection and pulmonary bactericidal activity to inhaled Klebsiella pneumoniae. When significant changes in these parameters were found, further exposures were performed at reduced vapor concentrations until the no-measurable-effect level was reached. Multiple exposures on 5 consecutive days were then performed at this concentration. Significant increases in susceptibility to respiratory streptococcus infection were observed after single 3-hr exposure to TLV concentrations of methylene chloride, perchloroethylene, and ethylene trichloride. For methylene chloride and perchloroethylene, these exposure conditions also resulted in significantly decreased pulmonary bactericidal activity.

  14. Effects of inhalation of organic chemical air contaminants on murine lung host defenses

    SciTech Connect

    Aranyi, C.; O'Shea, W.J.; Graham, J.A.; Miller, F.J.

    1986-01-01

    The potential health hazards of exposure to threshold limit value (TLV) concentrations of acetaldehyde, acrolein, propylene oxide, chloroform, methyl chloroform, carbon tetrachloride, allyl chloride, methylene chloride, ethylene trichloride, perchloroethylene, benzene, phenol, monochlorobenzene, and benzyl chloride, compounds which may be present in the ambient or work room atmosphere were investigated. The effects of single and multiple 3-hr inhalation exposures were evaluated in mice by monitoring changes in their susceptibility to experimentally induced streptococcus aerosol infection and pulmonary bactericidal activity to inhaled Klebsiella pneumoniae. When significant changes in these parameters were found, further exposures were performed at reduced vapor concentrations until the no-measurable-effect level was reached. Multiple exposures on 5 consecutive days were then performed at the concentration. Significant increases in susceptibility to respiratory streptococcus infection were observed after single 3-hr exposure to TLV concentrations of methylene chloride, perchloroethylene, and ethylene trichloride. For methylene chloride and perchloroethylene, these exposure conditions also resulted in significantly decreased pulmonary bactericidal activity.

  15. Assessing homeland chemical hazards outside the military gates: industrial hazard threat assessments for department of defense installations.

    PubMed

    Kirkpatrick, Jeffrey S; Howard, Jacqueline M; Reed, David A

    2002-04-01

    As part of comprehensive joint medical surveillance measures outlined by the Department of Defense, the US Army Center for Health Promotion and Preventive Medicine (USACHPPM) is beginning to assess environmental health threats to continental US military installations. A common theme in comprehensive joint medical surveillance, in support of Force Health Protection, is the identification and assessment of potential environmental health hazards, and the evaluation and documentation of actual exposures in both a continental US and outside a continental US setting. For the continental US assessments, the USACHPPM has utilized the US Environmental Protection Agency (EPA) database for risk management plans in accordance with Public Law 106-40, and the toxic release inventory database, in a state-of the art geographic information systems based program, termed the Consequence Assessment and Management Tool Set, or CATS, for assessing homeland industrial chemical hazards outside the military gates. As an example, the US EPA toxic release inventory and risk management plans databases are queried to determine the types and locations of industries surrounding a continental US military installation. Contaminants of concern are then ranked with respect to known toxicological and physical hazards, where they are then subject to applicable downwind hazard simulations using applicable meteorological and climatological data sets. The composite downwind hazard areas are mapped in relation to emergency response planning guidelines (ERPG), which were developed by the American Industrial Hygiene Association to assist emergency response personnel planning for catastrophic chemical releases. In addition, other geographic referenced data such as transportation routes, satellite imagery and population data are included in the operational, equipment, and morale risk assessment and management process. These techniques have been developed to assist military medical planners and operations

  16. Development of a biomedical data base on the medical aspects of chemical defense. Annual report, 19 November 1987-31 October 1988

    SciTech Connect

    Landry, L.A.

    1988-12-01

    This report documents a one-year period of activities encompassing the further development and maintenance of the automated information system known as the Chemical Agent Retrieval System (CARS) for the U.S. Army Medical Research Institute of Chemical Defense (USAMRICD). During the period 19 November 1987 through 31 December 1988, Associate Consultants, Inc. (ACI), creator of the prototype system, expanded the database with relevant research articles taken from USAMRICD research reports and CRDEC holdings, medical and scientific libraries within the Washington area, and on-line searches of machine-readable databases containing citations from the worldwide literature. Within the 12-month period, ACI also succeeded in modifying the CARS Thesaurus by making key revisions. The CARS Thesaurus now includes a faceted structure using general biomedical index terms and tree structures. Significant automation with the Automated Citation Tracking System (CITES) and the CARS Update Tracking System (CUTS) significantly increased the efficiency and level of production while providing reduced costs to the government.

  17. 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. PMID:27245091

  18. Defense/stress responses activated by chitosan in sycamore cultured cells.

    PubMed

    Malerba, Massimo; Crosti, Paolo; Cerana, Raffaella

    2012-01-01

    Chitosan (CHT) is a natural, non-toxic, and inexpensive compound obtained by partial alkaline deacetylation of chitin, the main component of the exoskeleton of crustaceans and other arthropods. The unique physiological and biological properties of CHT make this polymer useful for a wide range of industries. In agriculture, CHT is used to control numerous pre- and postharvest diseases on various horticultural commodities. In recent years, much attention has been devoted to CHT as an elicitor of defense responses in plants, which include raising of cytosolic Ca(2+), activation of MAP kinases, callose apposition, oxidative burst, hypersensitive response, synthesis of abscisic acid, jasmonate, phytoalexins, and pathogenesis-related proteins. In this work, we investigated the effects of different CHT concentrations on some defense/stress responses of sycamore (Acer pseudoplatanus L.) cultured cells. CHT induced accumulation of dead cells, and of cells with fragmented DNA, production of H(2)O(2) and nitric oxide, release of cytochrome c from the mitochondrion, accumulation of regulative 14-3-3 proteins in the cytosol and of HSP70 molecular chaperone binding protein in the endoplasmic reticulum, accompanied by marked modifications in the architecture of this cell organelle.

  19. Temporal accumulation of salicylic acid activates the defense response against Colletotrichum in strawberry.

    PubMed

    Grellet-Bournonville, Carlos F; Martinez-Zamora, Martín G; Castagnaro, Atilio P; Díaz-Ricci, Juan Carlos

    2012-05-01

    Many authors have reported interactions between strawberry cultivars and pathogenic microorganisms, yet little is known about the mechanisms triggered in the plant. In this paper we examine the participation of the salicylic acid (SA) signaling pathway involved in the response of Fragaria x ananassa cv. Pájaro plants to pathogens. Strawberry plants were challenged with the virulent strain M11 of Colletotrichum acutatum, or with the avirulent strain M23 of Colletotrichum fragariae which confers resistance to the former. Our study showed that the isolate M23 induced a temporal SA accumulation that was accompanied with the induction of PR-1 gene expression in strawberry plants. Such events occured after the oxidative burst, evaluated as the accumulation of hydrogen peroxide and superoxide anion, and many hours before the protection could be detected. Similar results were obtained with exogenously applied SA. Results obtained supports the hypothesis that strawberry plants activate a SA mediated defense mechanisms that is effective against a causal agent of anthracnose. In contrast, plants inoculated with M11 did not show oxidative burst, SA accumulation or PR1 gene induction. This is the first report about a defense response signaling pathway studied in strawberry plants. PMID:22366637

  20. Phenylpropanoid enzymes, phenolic polymers and metabolites as chemical defenses to infection of Pratylenchus coffeae in roots of resistant and susceptible bananas (Musa spp.).

    PubMed

    Vaganan, M Mayil; Ravi, I; Nandakumar, A; Sarumathi, S; Sundararaju, P; Mustaffa, M M

    2014-03-01

    Activity differences of the first (phenylalanine ammonia lyase, PAL) and the last (cinnamyl alcohol dehydrogenase, CAD) enzymes of phenylpropanoid pathway in the roots of resistant (Yangambi Km5 and Anaikomban) and susceptible (Nendran and Robusta) banana cultivars caused by root lesion nematode, Pratylenchus coffeae, were investigated. Also, the accumulation of phenolics and deposition of lignin polymers in cell walls in relation to resistance of the banana cultivars to the nematode were analyzed. Compared to the susceptible cultivars, the resistant cultivars had constitutively significantly higher PAL activity and total soluble and cell wall-bound phenolics than in susceptible cultivars. The resistant cultivars responded strongly to the infection of the nematode by induction of several-time higher PAL and CAD enzymes activities, soluble and wall-bound phenolics and enrichment of lignin polymers in cell wall and these biochemical parameters reached maximum at 7th day postinoculation. In addition, profiles of phenolic acid metabolites in roots of Yangambi Km5 and Nendran were analyzed by HPLC to ascertain the underlying biochemical mechanism of bananas resistance to the nematode. Identification and quantification of soluble and cell wall-bound phenolic acids showed six metabolites and only quantitative, no qualitative, differences occurred between the resistant and susceptible cvs. and between constitutive and induced contents. A very prominent increase of p-coumaric, ferulic and sinapic acids, which are precursors of monolignols of lignin, in resistant cv. was found. These constitutive and induced biochemical alterations are definitely the chemical defenses of resistant cvs. to the nematode infection.

  1. Immune regulatory activities of fowlicidin-1, a cathelicidin host defense peptide.

    PubMed

    Bommineni, Yugendar R; Pham, Giang H; Sunkara, Lakshmi T; Achanta, Mallika; Zhang, Guolong

    2014-05-01

    Appropriate modulation of immunity is beneficial in antimicrobial therapy and vaccine development. Host defense peptides (HDPs) constitute critically important components of innate immunity with both antimicrobial and immune regulatory activities. We previously showed that a chicken HDP, namely fowlicidin-1(6-26), has potent antibacterial activities in vitro and in vivo. Here we further revealed that fowl-1(6-26) possesses strong immunomodulatory properties. The peptide is chemotactic specifically to neutrophils, but not monocytes or lymphocytes, after injected into the mouse peritoneum. Fowl-1(6-26) also has the capacity to activate macrophages by inducing the expression of inflammatory mediators including IL-1β, CCL2, and CCL3. However, unlike bacterial lipopolysaccharide that triggers massive production of inflammatory cytokines and chemokines, fowl-1(6-26) only marginally increased their expression in mouse RAW264.7 macrophages. Additionally, fowl-1(6-26) enhanced the surface expression of MHC II and CD86 on RAW264.7 cells, suggesting that it may facilitate development of adaptive immune response. Indeed, co-immunization of mice with chicken ovalbumin (OVA) and fowl-1(6-26) augmented both OVA-specific IgG1 and IgG2a titers, relative to OVA alone. We further showed that fowl-1(6-26) is capable of preventing a methicillin-resistant Staphylococcus aureus (MRSA) infection due to its enhancement of host defense. All mice survived from an otherwise lethal infection when the peptide was administered 1-2 days prior to MRSA infection, and 50% mice were protected if receiving the peptide 4 days before infection. Taken together, with a strong capacity to stimulate innate and adaptive immunity, fowl-1(6-26) may have potential to be developed as a novel antimicrobial and a vaccine adjuvant.

  2. 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.

  3. Activity of potent and selective host defense peptide mimetics in mouse models of oral candidiasis.

    PubMed

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

    2014-07-01

    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.

  4. 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

  5. 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.

  6. 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. PMID:24644263

  7. Collective Surfing of Chemically Active Particles

    NASA Astrophysics Data System (ADS)

    Masoud, Hassan; Shelley, Michael J.

    2014-03-01

    We study theoretically the collective dynamics of immotile particles bound to a 2D surface atop a 3D fluid layer. These particles are chemically active and produce a chemical concentration field that creates surface-tension gradients along the surface. The resultant Marangoni stresses create flows that carry the particles, possibly concentrating them. For a 3D diffusion-dominated concentration field and Stokesian fluid we show that the surface dynamics of active particle density can be determined using nonlocal 2D surface operators. Remarkably, we also show that for both deep or shallow fluid layers this surface dynamics reduces to the 2D Keller-Segel model for the collective chemotactic aggregation of slime mold colonies. Mathematical analysis has established that the Keller-Segel model can yield finite-time, finite-mass concentration singularities. We show that such singular behavior occurs in our finite-depth system, and study the associated 3D flow structures.

  8. Collective surfing of chemically active particles.

    PubMed

    Masoud, Hassan; Shelley, Michael J

    2014-03-28

    We study theoretically the collective dynamics of immotile particles bound to a 2D surface atop a 3D fluid layer. These particles are chemically active and produce a chemical concentration field that creates surface-tension gradients along the surface. The resultant Marangoni stresses create flows that carry the particles, possibly concentrating them. For a 3D diffusion-dominated concentration field and Stokesian fluid we show that the surface dynamics of active particle density can be determined using nonlocal 2D surface operators. Remarkably, we also show that for both deep or shallow fluid layers this surface dynamics reduces to the 2D Keller-Segel model for the collective chemotactic aggregation of slime mold colonies. Mathematical analysis has established that the Keller-Segel model can yield finite-time, finite-mass concentration singularities. We show that such singular behavior occurs in our finite-depth system, and study the associated 3D flow structures. PMID:24724685

  9. Tetraploidization of diploid Dioscorea results in activation of the antioxidant defense system and increased heat tolerance.

    PubMed

    Zhang, Xiao-Yi; Hu, Chun-Gen; Yao, Jia-Ling

    2010-01-15

    Polyploidy is reported to show increased tolerance to environmental stress. In this work, tetraploid plants of Dioscorea zingiberensis were obtained by colchicine treatment of shoots propagated in vitro. The highest tetraploid induction rate was achieved by treatment with 0.15% colchicine for 24h. Diploid and tetraploid plants were exposed to normal (28 degrees C) and high temperature (42 degrees C) for 5d during which physiological indices were measured. Compared with diploid plants, relative electrolyte leakage and contents of malondialdehyde, superoxide anions and hydrogen peroxide were lower in tetraploids, while activities of antioxidant enzymes, such as superoxide dismutase, peroxidase, catalase, ascorbate peroxidase and glutathione reductase, were stimulated and antioxidants (ascorbic acid and glutathione) were maintained at high concentrations. These results indicate that tetraploid plants possess a stronger antioxidant defense system and increased heat tolerance. PMID:19692145

  10. 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.

  11. 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

  12. 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. PMID:25960069

  13. Programmed cell death in plants: a pathogen-triggered response activated coordinately with multiple defense functions.

    PubMed

    Greenberg, J T; Guo, A; Klessig, D F; Ausubel, F M

    1994-05-20

    In plants, the hypersensitive response (HR) to pathogens involves rapid cell death, which is hypothesized to arise from the activation of a cell death program. We describe mutant A. thaliana plants that contain lesions in a single accelerated cell death (ACD) gene called ACD2 and that bypass the need for pathogen exposure to induce the HR. acd2 plants that develop spontaneous lesions show typical HR characteristics both within the necrotic tissue and within the healthy part of the plant, including: modification of plant cell walls, resistance to bacterial pathogens, and accumulation of defense-related gene transcripts, the signal molecule salicylic acid and an antimicrobial compound. We propose that the ACD2 gene is involved in a pathway(s) that negatively regulates a genetically programmed HR.

  14. Mechanisms of intracellular defense and activity of free radical oxidation in rat myocardium in the dynamics of chronic fluorine intoxication.

    PubMed

    Zhukova, A G; Alekhina, D A; Sazontova, T G; Prokop'ev, Yu A; Gorokhova, L G; Stryapko, N V; Mikhailova, N N

    2013-12-01

    The mechanisms of intracellular defense and activity of free radical oxidation in the myocardium were studied in the dynamics of chronic fluorine intoxication. At the early stages of fluorine intoxication (day 3-week 3), the concentrations of defense proteins HIF-1α, HSC73, and HOx-2 and activity of the main metabolic enzymes increased, which promoted maintenance of cardiomyocyte structure and function at the normal physiological level. At late stages of fluorine intoxication (weeks 6 and 9), metabolic changes in the myocardium attest to high strain of the adaptive mechanisms.

  15. Chemical activation through super energy transfer collisions.

    PubMed

    Smith, Jonathan M; Nikow, Matthew; Ma, Jianqiang; Wilhelm, Michael J; Han, Yong-Chang; Sharma, Amit R; Bowman, Joel M; Dai, Hai-Lung

    2014-02-01

    Can a molecule be efficiently activated with a large amount of energy in a single collision with a fast atom? If so, this type of collision will greatly affect molecular reactivity and equilibrium in systems where abundant hot atoms exist. Conventional expectation of molecular energy transfer (ET) is that the probability decreases exponentially with the amount of energy transferred, hence the probability of what we label "super energy transfer" is negligible. We show, however, that in collisions between an atom and a molecule for which chemical reactions may occur, such as those between a translationally hot H atom and an ambient acetylene (HCCH) or sulfur dioxide, ET of chemically significant amounts of energy commences with surprisingly high efficiency through chemical complex formation. Time-resolved infrared emission observations are supported by quasi-classical trajectory calculations on a global ab initio potential energy surface. Results show that ∼10% of collisions between H atoms moving with ∼60 kcal/mol energy and HCCH result in transfer of up to 70% of this energy to activate internal degrees of freedom.

  16. 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.

  17. 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.

  18. Human Macrophage SCN5A Activates an Innate Immune Signaling Pathway for Antiviral Host Defense*

    PubMed Central

    Jones, Alexis; Kainz, Danielle; Khan, Faatima; Lee, Cara; Carrithers, Michael D.

    2014-01-01

    Pattern recognition receptors contain a binding domain for pathogen-associated molecular patterns coupled to a signaling domain that regulates transcription of host immune response genes. Here, a novel mechanism that links pathogen recognition to channel activation and downstream signaling is proposed. We demonstrate that an intracellular sodium channel variant, human macrophage SCN5A, initiates signaling and transcription through a calcium-dependent isoform of adenylate cyclase, ADCY8, and the transcription factor, ATF2. Pharmacological stimulation with a channel agonist or treatment with cytoplasmic poly(I:C), a mimic of viral dsRNA, activates this pathway to regulate expression of SP100-related genes and interferon β. Electrophysiological analysis reveals that the SCN5A variant mediates nonselective outward currents and a small, but detectable, inward current. Intracellular poly(I:C) markedly augments an inward voltage-sensitive sodium current and inhibits the outward nonselective current. These results suggest human macrophage SCN5A initiates signaling in an innate immune pathway relevant to antiviral host defense. It is postulated that SCN5A is a novel pathogen sensor and that this pathway represents a channel activation-dependent mechanism of transcriptional regulation. PMID:25368329

  19. Diversity and chemical defense role of culturable non-actinobacterial bacteria isolated from the South China Sea gorgonians.

    PubMed

    Peng, Jiang; Zhang, Xiaoyong; Xu, Xinya; He, Fei; Qi, Shuhua

    2013-04-01

    The diversity of culturable non-actinobacterial (NA) bacteria associated with four species of South China Sea gorgonians was investigated using culture-dependent methods followed by analysis of the bacterial 16S rDNA sequence. A total of 76 bacterial isolates were recovered and identified, which belonged to 21 species of 7 genera, and Bacillus was the most diverse genus. Fifty-one percent of the 76 isolates displayed antibacterial activities, and most of them belonged to the Bacillus genus. From the culture broth of gorgonian-associated Bacillus methylotrophicus SCSGAB0092 isolated from gorgonian Melitodes squamata, 11 antimicrobial lipopeptides including seven surfactins and four iturins were obtained. These results imply that Bacillus strains associated with gorgonians play roles in coral defense mechanisms through producing antimicrobial substances. This study, for the first time, compares the diversity of culturable NA bacterial communities among four species of South China Sea gorgonians and investigates the secondary metabolites of gorgonian-associated B. methylotrophicus SCSGAB0092.

  20. Intracellular Oxidant Activity, Antioxidant Enzyme Defense System, and Cell Senescence in Fibroblasts with Trisomy 21

    PubMed Central

    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. PMID:25852816

  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. A Role for Host Activation-Induced Cytidine Deaminase in Innate Immune Defense against KSHV

    PubMed Central

    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. PMID:24244169

  3. 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 LICENSING OF PRODUCTION AND UTILIZATION FACILITIES Requirement of License, Exceptions § 50.13 Attacks and destructive acts by enemies of the United...

  4. 10 CFR 50.13 - Attacks and destructive acts by enemies of the United States; and defense activities.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 1 2010-01-01 2010-01-01 false Attacks and destructive acts by enemies of the United... destructive acts by enemies of the United States; and defense activities. An applicant for a license to... an enemy of the United States, whether a foreign government or other person, or (b) use or...

  5. 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...

  6. 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...

  7. 18 CFR 2.60 - Facilities and activities during an emergency-accounting treatment of defense-related expenditures.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 18 Conservation of Power and Water Resources 1 2014-04-01 2014-04-01 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...

  8. 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...

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

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... Natural Gas Act § 2.60 Facilities and activities during an emergency—accounting treatment of defense-related expenditures. The Commission, cognizant of the need of the natural gas industry for advice with respect to the applicability of the Natural Gas Act and the Commission's regulations thereunder...

  10. Active Chemical Thermodynamics promoted by activity of cortical actin

    NASA Astrophysics Data System (ADS)

    Bhattacharya, Bhaswati; Chaudhuri, Abhishek; Gowrishankar, Kripa; Rao, Madan

    2011-03-01

    The spatial distribution and dynamics of formation and breakup of the nanoclusters of cell surface proteins is controlled by the active remodeling dynamics of the underlying cortical actin. To explain these observations, we have proposed a novel mechanism of nanoclustering, involving the transient binding to and advection along constitutively occuring ``asters'' of cortical actin. We study the consequences of such active actin-based clustering, in the context of chemical reactions involving conformational changes of cell surface proteins. We find that the active remodeling of cortical actin, can give rise to a dramatic increase in efficiency and extent of conformational spread, even at low levels of expression at the cell surface. We define a activity temperature (τa) arising due to actin activities which can be used to describe chemical thermodynamics of the system. We plot TTT (time-temparature-transformation) curves and compute the Arrhenius factors which depend on τa . With this, the active asters can be treated as enzymes whose enzymatic reaction rate can be related to the activity.

  11. 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.

  12. 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. PMID:22431987

  13. Preparation of activated carbon by chemical activation under vacuum.

    PubMed

    Juan, Yang; Ke-Qiang, Qiu

    2009-05-01

    Activated carbons especially used for gaseous adsorption were prepared from Chinesefir sawdust by zinc chloride activation under vacuum condition. The micropore structure, adsorption properties, and surface morphology of activated carbons obtained under atmosphere and vacuum were investigated. The prepared activated carbons were characterized by SEM, FTIR, and nitrogen adsorption. It was found that the structure of the starting material is kept after activation. The activated carbon prepared under vacuum exhibited higher values of the BET surface area (up to 1079 m2 g(-1)) and total pore volume (up to 0.5665 cm3 g(-1)) than those of the activated carbon obtained under atmosphere. This was attributed to the effect of vacuum condition that reduces oxygen in the system and limits the secondary reaction of the organic vapor. The prepared activated carbon has well-developed microstructure and high microporosity. According to the data obtained, Chinese fir sawdust is a suitable precursor for activated carbon preparation. The obtained activated carbon could be used as a low-cost adsorbent with favorable surface properties. Compared with the traditional chemical activation, vacuum condition demands less energy consumption, simultaneity, and biomass-oil is collected in the procedure more conveniently. FTIR analysis showed that heat treatment would result in the aromatization of the carbon structure. PMID:19534162

  14. 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

  15. 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

  16. 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.

  17. 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.

  18. Ozone Sensitivity in Hybrid Poplar Is Correlated with a Lack of Defense-Gene Activation1

    PubMed Central

    Riehl Koch, Jennifer; Scherzer, Amy J.; Eshita, Steven M.; Davis, Keith R.

    1998-01-01

    Ozone is a major gaseous pollutant thought to contribute to forest decline. Although the physiological and morphological responses of forest trees to ozone have been well characterized, little is known about the molecular basis for these responses. Our studies compared the response to ozone of ozone-sensitive and ozone-tolerant clones of hybrid poplar (Populus maximowizii × Populus trichocarpa) at the physiological and molecular levels. Gas-exchange analyses demonstrated clear differences between the ozone-sensitive clone 388 and the ozone-tolerant clone 245. Although ozone induced a decrease in photosynthetic rate and stomatal conductance in both clones, the magnitude of the decrease in stomatal conductance was significantly greater in the ozone-tolerant clone. RNA-blot analysis established that ozone-induced mRNA levels for phenylalanine ammonia-lyase, O-methyltransferase, a pathogenesis-related protein, and a wound-inducible gene were significantly higher in the ozone-tolerant than in the ozone-sensitive plants. Wound- and pathogen-induced levels of these mRNAs were also higher in the ozone-tolerant compared with the ozone-sensitive plants. The different physiological and molecular responses to ozone exposure exhibited by clones 245 and 388 suggest that ozone tolerance involves the activation of salicylic-acid- and jasmonic-acid-mediated signaling pathways, which may be important in triggering defense responses against oxidative stress. PMID:9847098

  19. 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. PMID:25477684

  20. A Diverse Family of Host-Defense Peptides (Piscidins) Exhibit Specialized Anti-Bacterial and Anti-Protozoal Activities in Fishes.

    PubMed

    Salger, Scott A; Cassady, Katherine R; Reading, Benjamin J; 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

  1. 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

  2. A Diverse Family of Host-Defense Peptides (Piscidins) Exhibit Specialized Anti-Bacterial and Anti-Protozoal Activities in Fishes.

    PubMed

    Salger, Scott A; Cassady, Katherine R; Reading, Benjamin J; 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.

  3. 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.

  4. 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.

  5. A subtilisin-like protein from soybean contains an embedded, cryptic signal that activates defense-related genes

    PubMed Central

    Pearce, Gregory; Yamaguchi, Yube; Barona, Guido; Ryan, Clarence A.

    2010-01-01

    Among the arsenal of plant-derived compounds activated upon attack by herbivores and pathogens are small peptides that initiate and amplify defense responses. However, only a handful of plant signaling peptides have been reported. Here, we have isolated a 12-aa peptide from soybean (Glycine max) leaves that causes a pH increase of soybean suspension-cultured cell media within 10 min at low nanomolar concentrations, a response that is typical of other endogenous peptide elicitors and pathogen-derived elicitors. The amino acid sequence was determined and was found to be derived from a member of the subtilisin-like protease (subtilase) family. The sequence of the peptide was located within a region of the protein that is unique to subtilases in legume plants and not found within any other plant subtilases thus far identified. We have named this peptide signal Glycine max Subtilase Peptide (GmSubPep). The gene (Glyma18g48580) was expressed in all actively growing tissues of the soybean plant. Although transcription of Glyma18g48580 was not induced by wounding, methyl jasmonate, methyl salicylate, or ethephon, synthetic GmSubPep peptide, when supplied to soybean cultures, induced the expression of known defense-related genes, such as Cyp93A1, Chib-1b, PDR12, and achs. GmSubPep is a unique plant defense peptide signal, cryptically embedded within a plant protein with an independent metabolic role, providing insights into plant defense mechanisms. PMID:20679205

  6. The nuclear immune receptor RPS4 is required for RRS1SLH1-dependent constitutive defense activation in Arabidopsis thaliana.

    PubMed

    Sohn, Kee Hoon; Segonzac, Cécile; Rallapalli, Ghanasyam; Sarris, Panagiotis F; Woo, Joo Yong; Williams, Simon J; Newman, Toby E; Paek, Kyung Hee; Kobe, Bostjan; Jones, Jonathan D G

    2014-10-01

    Plant nucleotide-binding leucine-rich repeat (NB-LRR) disease resistance (R) proteins recognize specific "avirulent" pathogen effectors and activate immune responses. NB-LRR proteins structurally and functionally resemble mammalian Nod-like receptors (NLRs). How NB-LRR and NLR proteins activate defense is poorly understood. The divergently transcribed Arabidopsis R genes, RPS4 (resistance to Pseudomonas syringae 4) and RRS1 (resistance to Ralstonia solanacearum 1), function together to confer recognition of Pseudomonas AvrRps4 and Ralstonia PopP2. RRS1 is the only known recessive NB-LRR R gene and encodes a WRKY DNA binding domain, prompting suggestions that it acts downstream of RPS4 for transcriptional activation of defense genes. We define here the early RRS1-dependent transcriptional changes upon delivery of PopP2 via Pseudomonas type III secretion. The Arabidopsis slh1 (sensitive to low humidity 1) mutant encodes an RRS1 allele (RRS1SLH1) with a single amino acid (leucine) insertion in the WRKY DNA-binding domain. Its poor growth due to constitutive defense activation is rescued at higher temperature. Transcription profiling data indicate that RRS1SLH1-mediated defense activation overlaps substantially with AvrRps4- and PopP2-regulated responses. To better understand the genetic basis of RPS4/RRS1-dependent immunity, we performed a genetic screen to identify suppressor of slh1 immunity (sushi) mutants. We show that many sushi mutants carry mutations in RPS4, suggesting that RPS4 acts downstream or in a complex with RRS1. Interestingly, several mutations were identified in a domain C-terminal to the RPS4 LRR domain. Using an Agrobacterium-mediated transient assay system, we demonstrate that the P-loop motif of RPS4 but not of RRS1SLH1 is required for RRS1SLH1 function. We also recapitulate the dominant suppression of RRS1SLH1 defense activation by wild type RRS1 and show this suppression requires an intact RRS1 P-loop. These analyses of RRS1SLH1 shed new light

  7. 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.

  8. Stress perceptions of soldiers participating in training at the Chemical Defense Training Facility: The mediating effects of motivation, experience, and confidence level. Final report

    SciTech Connect

    Fatkin, L.T.; Hudgens, G.A.

    1994-01-01

    An investigation was conducted by the U.S. Army Research Laboratory (ARL) and funded by the Physiological and Psychological Effects of the Nuclear, Biological, and Chemical (NBC) Environment and Sustained Operations on Systems in Combat (P2NBC2) program to assess the psychological reactions of soldiers in mission-oriented protective posture (MOPP) IV participating in training in a simulated chemical agent environment and in a toxic agent environment. A total of 155 soldiers who participated in the basic course (junior enlisted) and the advanced courses (officer and noncommissioned officer NCO groups) as part of their military occupational specialty (MOS) training volunteered for the study. The junior enlisted group reported significant increases in anxiety during four sessions as they approached the toxic agent portion of the training. The more experienced groups showed a small, but significant increase in anxiety during sessions. Their level of hostility, a component of stress that usually relates to levels of personal frustration, decreased significantly from the time of their initial testing to just before the training began. Since the initial session occurred 1 to 2 weeks before the U.S. Army Chemical Defense Training Facility (CDTF) training, the elevated frustration level may be a reflection of their overall experiences within the intensive chemical defense training program. A significant drop in reported fatigue between the pre- and post-training sessions may indicate a certain level of vigilance gained by participating in the training.

  9. Chemical defense secretions of the termite soldiers ofAcorhinotermes andRhinotermes (Isoptera, Rhinotermitinae) : Ketones, vinyl ketones, and β-ketoaldehydes derived from fatty acids.

    PubMed

    Prestwich, G D; Collins, M S

    1982-01-01

    The defense secretions of advanced "nasutoid" rhinotermitine soldiers from the New World contain enolic β-ketoaldehydes as the major components. The secretions of minor soldiers ofRhinotermes hispidus (Emerson) andR. marginalis (Emerson) consist primarily of 3-keto-13-tetradecenal and 3-ketotetradecanal, but possess in addition C13, C14, C15, and C17 saturated and unsaturated ketones. Major soldiers lacked these compounds and in fact had virtually no frontal gland secretion. The defense secretion of the monomorphic soldiers ofAcorhinotermes subfusciceps (Emerson) contains mostly 3-keto-(Z)-9-hexadecenal and (Z)-8-pentadecen-2-one. Biosynthetic origins and interrelationships are postulated for these compounds, and the concomitant evolution of chemical weaponry and the modified labral brush is discussed. PMID:24414591

  10. Gall insects and indirect plant defenses: A case of active manipulation?

    PubMed

    Tooker, John F; De Moraes, Consuelo M

    2008-07-01

    Many plants can defend themselves against insect herbivory by attracting natural enemies that kill feeding herbivores and limit the damage they inflict. Such "indirect defenses" can be induced by insects feeding on different plant tissues and using a variety of feeding styles. However, we have recently shown that gall-inducing insect species can avoid the indirect defenses of their host plant species and even alter volatile emissions following subsequent herbivory. One of the species we studied, Eurosta solidaginis, induces galls on goldenrod (Solidago altissima) and appears to exert a unique influence over the indirect defenses of its host plant that is not readily explained by levels of defense-related phytohormones, gall formation or resource depletion. Our evidence suggests that this gall-insect species may be able to manipulate its host plant species to avoid and/or modify its defensive responses. The results also provide insight into gall induction because the gall-insect species that we screened did not increase levels of jasmonic acid, which, in addition to triggering volatile emissions, is a powerful growth regulator that could prevent the cell growth and division that leads to gall formation.

  11. 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.

  12. 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

  13. Receptor-mediated activation of a plant Ca2+-permeable ion channel involved in pathogen defense

    PubMed Central

    Zimmermann, Sabine; Nürnberger, Thorsten; Frachisse, Jean-Marie; Wirtz, Wolfgang; Guern, Jean; Hedrich, Rainer; Scheel, Dierk

    1997-01-01

    Pathogen recognition at the plant cell surface typically results in the initiation of a multicomponent defense response. Transient influx of Ca2+ across the plasma membrane is postulated to be part of the signaling chain leading to pathogen resistance. Patch-clamp analysis of parsley protoplasts revealed a novel Ca2+-permeable, La3+-sensitive plasma membrane ion channel of large conductance (309 pS in 240 mM CaCl2). At an extracellular Ca2+ concentration of 1 mM, which is representative of the plant cell apoplast, unitary channel conductance was determined to be 80 pS. This ion channel (LEAC, for large conductance elicitor-activated ion channel) is reversibly activated upon treatment of parsley protoplasts with an oligopeptide elicitor derived from a cell wall protein of Phytophthora sojae. Structural features of the elicitor found previously to be essential for receptor binding, induction of defense-related gene expression, and phytoalexin formation are identical to those required for activation of LEAC. Thus, receptor-mediated stimulation of this channel appears to be causally involved in the signaling cascade triggering pathogen defense in parsley. PMID:11038609

  14. Heat treatment in combination with antagonistic yeast reduces diseases and elicits the active defense responses in harvested cherry tomato fruit.

    PubMed

    Zhao, Yan; Tu, Kang; Su, Jing; Tu, Sicong; Hou, Yuepeng; Liu, Fengjuan; Zou, Xiurong

    2009-08-26

    This study investigated the effects of heat treatment (hot air at 38 degrees C) and antagonistic yeast (Pichia guilliermondii) alone or in combination against postharvest diseases (Botrytis cinerea, Alternaria alternata and Rhizopus nigricans) on cherry tomato fruit, and evaluated the elicitation of active defense responses. Results showed that heat treatment at 38 degrees C for 24 h in combination with P. guilliermondii at 1 x 10(8) CFU mL(-1) was the most effective approach to reduce various infections on cherry tomato fruit's wounds. Moreover, the combined heat and P. guilliermondii treatment stimulated a rapid increase of H(2)O(2) and higher lignin deposition in cherry tomato fruit showing that the oxidative burst and biological synthesis of lignin might play important roles in the fruit's active defense responses. In addition, the reduction of the fruit's susceptibility to pathogens by the combined treatment was positively correlated with higher activities of phenylalanine ammonia-lyase (PAL) and beta-1,3-glucanase in cherry tomato fruits, both of which are associated with plant defense responses.

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

    PubMed

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

    2014-10-17

    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.

  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. Environmental evaluation of alternatives for long-term management of Defense high-level radioactive wastes at the Idaho Chemical Processing Plant

    SciTech Connect

    Not Available

    1982-09-01

    The U.S. Department of Energy (DOE) is considering the selection of a strategy for the long-term management of the defense high-level wastes at the Idaho Chemical Processing Plant (ICPP). This report describes the environmental impacts of alternative strategies. These alternative strategies include leaving the calcine in its present form at the Idaho National Engineering Laboratory (INEL), or retrieving and modifying the calcine to a more durable waste form and disposing of it either at the INEL or in an offsite repository. This report addresses only the alternatives for a program to manage the high-level waste generated at the ICPP. 24 figures, 60 tables.

  18. 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...

  19. 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.

  20. 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.

  1. Plant Defense Mechanisms Are Activated during Biotrophic and Necrotrophic Development of Colletotricum graminicola in Maize1[W][OA

    PubMed Central

    Vargas, Walter A.; Martín, José M. Sanz; Rech, Gabriel E.; Rivera, Lina P.; Benito, Ernesto P.; Díaz-Mínguez, José M.; Thon, Michael R.; Sukno, Serenella A.

    2012-01-01

    Hemibiotrophic plant pathogens first establish a biotrophic interaction with the host plant and later switch to a destructive necrotrophic lifestyle. Studies of biotrophic pathogens have shown that they actively suppress plant defenses after an initial microbe-associated molecular pattern-triggered activation. In contrast, studies of the hemibiotrophs suggest that they do not suppress plant defenses during the biotrophic phase, indicating that while there are similarities between the biotrophic phase of hemibiotrophs and biotrophic pathogens, the two lifestyles are not analogous. We performed transcriptomic, histological, and biochemical studies of the early events during the infection of maize (Zea mays) with Colletotrichum graminicola, a model pathosystem for the study of hemibiotrophy. Time-course experiments revealed that mRNAs of several defense-related genes, reactive oxygen species, and antimicrobial compounds all begin to accumulate early in the infection process and continue to accumulate during the biotrophic stage. We also discovered the production of maize-derived vesicular bodies containing hydrogen peroxide targeting the fungal hyphae. We describe the fungal respiratory burst during host infection, paralleled by superoxide ion production in specific fungal cells during the transition from biotrophy to a necrotrophic lifestyle. We also identified several novel putative fungal effectors and studied their expression during anthracnose development in maize. Our results demonstrate a strong induction of defense mechanisms occurring in maize cells during C. graminicola infection, even during the biotrophic development of the pathogen. We hypothesize that the switch to necrotrophic growth enables the fungus to evade the effects of the plant immune system and allows for full fungal pathogenicity. PMID:22247271

  2. 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. PMID:22243492

  3. Nonenzymatic Lipid Peroxidation Reprograms Gene Expression and Activates Defense Markers in Arabidopsis Tocopherol-Deficient Mutants[W

    PubMed Central

    Sattler, Scott E.; Mène-Saffrané, Laurent; Farmer, Edward E.; Krischke, Markus; Mueller, Martin J.; DellaPenna, Dean

    2006-01-01

    Tocopherols (vitamin E) are lipophilic antioxidants that are synthesized by all plants and are particularly abundant in seeds. Two tocopherol-deficient mutant loci in Arabidopsis thaliana were used to examine the functions of tocopherols in seedlings: vitamin e1 (vte1), which accumulates the pathway intermediate 2,3-dimethyl-5-phytyl-1,4-benzoquinone (DMPBQ); and vte2, which lacks all tocopherols and pathway intermediates. Only vte2 displayed severe seedling growth defects, which corresponded with massively increased levels of the major classes of nonenzymatic lipid peroxidation products: hydroxy fatty acids, malondialdehyde, and phytoprostanes. In the absence of pathogens, the phytoalexin camalexin accumulated in vte2 seedlings to levels 100-fold higher than in wild-type or vte1 seedlings. Similarly, gene expression profiling in wild-type, vte1, and vte2 seedlings indicated that increased levels of nonenzymatic lipid peroxidation in vte2 corresponded to increased expression of many defense-related genes, which were not induced in vte1. Both biochemical and transcriptional analyses of vte2 seedlings indicate that nonenzymatic lipid peroxidation plays a significant role in modulating plant defense responses. Together, these results establish that tocopherols in wild-type plants or DMPBQ in vte1 plants limit nonenzymatic lipid peroxidation during germination and early seedling development, thereby preventing the inappropriate activation of transcriptional and biochemical defense responses. PMID:17194769

  4. 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.

  5. Fowlicidin-3 is an alpha-helical cationic host defense peptide with potent antibacterial and lipopolysaccharide-neutralizing activities.

    PubMed

    Bommineni, Yugendar R; Dai, Huaien; Gong, Yu-Xi; Soulages, Jose L; Fernando, Samodha C; Desilva, Udaya; Prakash, Om; Zhang, Guolong

    2007-01-01

    Cathelicidins are an important family of cationic host defense peptides in vertebrates with both antimicrobial and immunomodulatory activities. Fowlicidin-1 and fowlicidin-2 are two newly identified chicken cathelicidins with potent antibacterial activities. Here we report structural and functional characterization of the putatively mature form of the third chicken cathelicidin, fowlicidin-3, for exploration of its therapeutic potential. NMR spectroscopy revealed that fowlicidin-3 comprises 27 amino-acid residues and adopts a predominantly alpha-helical structure extending from residue 9 to 25 with a slight kink induced by a glycine at position 17. It is highly potent against a broad range of Gram-negative and Gram-positive bacteria in vitro, including antibiotic-resistant strains, with minimum inhibitory concentrations in the range 1-2 microM. It kills bacteria quickly, permeabilizing cytoplasmic membranes immediately on coming into contact with them. Unlike many other host defense peptides with antimicrobial activities that are diminished by serum or salt, fowlicidin-3 retains bacteria-killing activities in the presence of 50% serum or physiological concentrations of salt. Furthermore, it is capable of suppressing lipopolysaccharide-induced expression of proinflammatory genes in mouse macrophage RAW264.7 cells, with nearly complete blockage at 10 microM. Fowlicidin-3 appears to be an excellent candidate for future development as a novel antimicrobial and antisepsis agent, particularly against antibiotic-resistant pathogens.

  6. SOME CHEMICAL PROPERTIES UNDERLYING ARSENIC'S BIOLOGICAL ACTIVITY

    EPA Science Inventory

    ABSTRACT

    In this paper some of the chemical properties of arsenicals (atomic
    and molecular orbitals, electronegativity, valence state, changes between
    valence state, nucleophilicity, the hard/soft acid/base principle) that may
    account for some of the b...

  7. Rendering the inedible edible: Circumvention of a millipede’s chemical defense by a predaceous beetle larva (Phengodidae)

    PubMed Central

    Eisner, Thomas; Eisner, Maria; Attygalle, Athula B.; Deyrup, Mark; Meinwald, Jerrold

    1998-01-01

    The larva of the phengodid beetle, Phengodes laticollis, feeds on the millipede, Floridobolus penneri, without risking exposure to the repellent benzoquinones ordinarily ejected by the millipede from its defensive glands when attacked. The phengodid subdues the millipede by piercing the millipede’s integument with its hollow sickle-shaped mandibles and apparently injecting gastric fluid. The infusion abruptly paralyzes the millipede, which thereby is prevented from discharging its glands. As the phengodid then imbibes the liquefied systemic contents of the dead millipede, the millipede’s benzoquinones remain harmlessly confined to the glands, prevented from diffusing into the millipede’s body cavity by the glands’ impervious cuticular lining. At the end of the meal only the millipede’s skeletal armor and glandular sacs remain uneaten. Analysis of such discarded sacs showed these to contain benzoquinones in amounts commensurate with those present in replete glands of living millipedes. PMID:9448293

  8. Systemic Activation of TLR3-Dependent TRIF Signaling Confers Host Defense against Gram-Negative Bacteria in the Intestine.

    PubMed

    Ruiz, Jose; Kanagavelu, Saravana; Flores, Claudia; Romero, Laura; Riveron, Reldy; Shih, David Q; Fukata, Masayuki

    2015-01-01

    Recognition of Gram-negative bacteria by toll-like receptor (TLR)4 induces MyD88 and TRIF mediated responses. We have shown that TRIF-dependent responses play an important role in intestinal defense against Gram-negative enteropathogens. In the current study, we examined underlying mechanisms of how systemic TRIF activation enhances intestinal immune defense against Gram-negative bacteria. First we confirmed that the protective effect of poly I:C against enteric infection of mice with Yersinia enterocolitica was dependent on TLR3-mediated TRIF signaling by using TLR3-deficient mice. This protection was unique in TRIF-dependent TLR signaling because systemic stimulation of mice with agonists for TLR2 (Pam3CSK4) or TLR5 (flagellin) did not reduce mortality on Y. enterocolitica infection. Systemic administration of poly I:C mobilized CD11c+, F4/80+, and Gr-1(hi) cells from lamina propria and activated NK cells in the mesenteric lymph nodes (MLN) within 24 h. This innate immune cell rearrangement was type I IFN dependent and mediated through upregulation of TLR4 followed by CCR7 expression in these innate immune cells found in the intestinal mucosa. Poly I:C induced IFN-γ expression by NK cells in the MLN, which was mediated through type I IFNs and IL-12p40 from antigen presenting cells and consequent activation of STAT1 and STAT4 in NK cells. This formation of innate immunity significantly contributed to the elimination of bacteria in the MLN. Our results demonstrated an innate immune network in the intestine that can be established by systemic stimulation of TRIF, which provides a strong host defense against Gram-negative pathogens. The mechanism underlying TRIF-mediated protective immunity may be useful to develop novel therapies for enteric bacterial infection.

  9. Intra-plant differences in seaweed nutritional quality and chemical defenses: Importance for the feeding behavior of the intertidal amphipod Orchestoidea tuberculata

    NASA Astrophysics Data System (ADS)

    Duarte, Cristian; Acuña, Karin; Navarro, Jorge M.; Gómez, Iván

    2011-10-01

    As a result of their morphological complexity, large macroalgae show intra-thallus variations in their nutritional composition and secondary metabolite content, which influences the trophic ecology of herbivorous invertebrates, and ultimately their fitness. In this study, we evaluated for the first time the variability in nutritional quality (protein content, carbohydrates, lipids, and total organic matter), secondary metabolites (phlorotannins), and structure (shape and toughness) between blades and stipes of the macroalgae Durvillaea Antarctica. Specifically, we looked at their effect on feeding preference, rate of consumption, absorption efficiency, and growth rate of the amphipod Orchestoidea tuberculata, one of the most abundant organisms on Chilean sandy beaches. Proteins, carbohydrates, total organic matter and phlorotannin contents were significantly higher in blades than in stipes. Preference experiments revealed that the amphipods preferred blades when fresh pieces of blades and stipes were offered at the same time. Similar results were found when artificial food (in which structures of both parts of the alga were standardized) was offered, suggesting that shape and toughness of the two different parts of the alga did not influence preference patterns of O. tuberculata. Absorption efficiency of O. tuberculata was higher on blades compared to stipes. When the amphipods were kept with each of the algal parts separately (i.e. no choice), they consumed a significantly higher amount of stipe, which suggests that O. tuberculata used food quantity to compensate for the lower nutritional quality of stipes. The higher nutritional values of blades compared to stipes appears to explain observed preference patterns by O. tuberculata. Phlorotannin content did not appear to inhibit blade consumption, suggesting that the nutritional quality of the food could be more important than chemical defense in determining food choice in O. tuberculata. Growth did not differ

  10. Defensive activation to (un)predictable interoceptive threat: The NPU respiratory threat test (NPUr).

    PubMed

    Schroijen, Mathias; Fantoni, Simona; Rivera, Carmen; Vervliet, Bram; Schruers, Koen; van den Bergh, Omer; van Diest, Ilse

    2016-06-01

    Potentially life-threatening interoceptive sensations easily engage the behavioral defensive system. Resulting fear and anxiety toward interoceptive threat are functionally distinct states that are hypothesized to play a prominent role in the etiology of panic disorder. The present study aimed to investigate whether fear- and anxiety-potentiated startle responses occur to predictable and unpredictable interoceptive threat, respectively. Therefore, we modified the NPU threat test (Schmitz & Grillon, ) and replaced the aversive electrocutaneous stimulus with an aversive interoceptive stimulus (a breathing occlusion, making it briefly impossible to breathe). Healthy participants (N = 48) underwent three instructed conditions. A visual cue signaled the occlusion in the predictable condition (P), whereas another cue was unrelated to the occurrence of the occlusion in the unpredictable condition (U). The safe condition (N) also had a visual cue, but no occlusion. Both fear- and anxiety-potentiated startle blink responses were observed in response to predictable and unpredictable respiratory threat, respectively. The current study presents and validates the NPU respiratory threat test (NPUr) as an ecologically valid paradigm to study both anxiety and fear in response to a panic-relevant interoceptive threat. The paradigm allows future testing of contextual generalization, investigation of different clinical groups, and more explicit comparisons of defensive responding to interoceptive versus exteroceptive threats.

  11. Defensive activation to (un)predictable interoceptive threat: The NPU respiratory threat test (NPUr).

    PubMed

    Schroijen, Mathias; Fantoni, Simona; Rivera, Carmen; Vervliet, Bram; Schruers, Koen; van den Bergh, Omer; van Diest, Ilse

    2016-06-01

    Potentially life-threatening interoceptive sensations easily engage the behavioral defensive system. Resulting fear and anxiety toward interoceptive threat are functionally distinct states that are hypothesized to play a prominent role in the etiology of panic disorder. The present study aimed to investigate whether fear- and anxiety-potentiated startle responses occur to predictable and unpredictable interoceptive threat, respectively. Therefore, we modified the NPU threat test (Schmitz & Grillon, ) and replaced the aversive electrocutaneous stimulus with an aversive interoceptive stimulus (a breathing occlusion, making it briefly impossible to breathe). Healthy participants (N = 48) underwent three instructed conditions. A visual cue signaled the occlusion in the predictable condition (P), whereas another cue was unrelated to the occurrence of the occlusion in the unpredictable condition (U). The safe condition (N) also had a visual cue, but no occlusion. Both fear- and anxiety-potentiated startle blink responses were observed in response to predictable and unpredictable respiratory threat, respectively. The current study presents and validates the NPU respiratory threat test (NPUr) as an ecologically valid paradigm to study both anxiety and fear in response to a panic-relevant interoceptive threat. The paradigm allows future testing of contextual generalization, investigation of different clinical groups, and more explicit comparisons of defensive responding to interoceptive versus exteroceptive threats. PMID:26879710

  12. 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).

  13. ILO activities in the area of chemical safety.

    PubMed

    Obadia, Isaac

    2003-08-21

    The ILO has been active in the area of safety in the use of chemicals at work since the year of its creation in 1919, including the development of international treaties and other technical instruments, the provision of technical assistance to its member States, and the development of chemical safety information systems. The two key ILO standards in this area are the Conventions on safety in the use of chemicals at work (No. 170, 1990), and the Prevention of Major Industrial Accidents (No. 174, 1993). The ILO Programme on occupational safety, health and environment (Safe Work) is currently responsible for ILO chemical safety activities. In the past two decades, most of ILO work in this area has been carried out within the context of inter-agency collaboration frameworks linking the ILO, WHO, UNEP, FAO, UNIDO, UNITAR, and the OECD, including the International Programme on Chemical Safety (IPCS), the Inter-Organisation Programme for the Sound Management of Chemicals (IOMC), and the Intergovernmental Forum on Chemical Safety (IFCS). Apart from the regular development, updating and dissemination of chemical safety information data bases such as the IPCS International Chemical Cards, the elaboration of a Globally harmonized system for the classification and labelling of Chemicals (GHS) has been the most outstanding achievement of this international collaboration on chemical safety.

  14. ILO activities in the area of chemical safety.

    PubMed

    Obadia, Isaac

    2003-08-21

    The ILO has been active in the area of safety in the use of chemicals at work since the year of its creation in 1919, including the development of international treaties and other technical instruments, the provision of technical assistance to its member States, and the development of chemical safety information systems. The two key ILO standards in this area are the Conventions on safety in the use of chemicals at work (No. 170, 1990), and the Prevention of Major Industrial Accidents (No. 174, 1993). The ILO Programme on occupational safety, health and environment (Safe Work) is currently responsible for ILO chemical safety activities. In the past two decades, most of ILO work in this area has been carried out within the context of inter-agency collaboration frameworks linking the ILO, WHO, UNEP, FAO, UNIDO, UNITAR, and the OECD, including the International Programme on Chemical Safety (IPCS), the Inter-Organisation Programme for the Sound Management of Chemicals (IOMC), and the Intergovernmental Forum on Chemical Safety (IFCS). Apart from the regular development, updating and dissemination of chemical safety information data bases such as the IPCS International Chemical Cards, the elaboration of a Globally harmonized system for the classification and labelling of Chemicals (GHS) has been the most outstanding achievement of this international collaboration on chemical safety. PMID:12909402

  15. Thermal stress imposed by prototype bilayer and current ground crew chemical defense ensembles: a limited laboratory comparison. Final report, 30 June 1986-1 January 1987

    SciTech Connect

    Krock, L.P.; Navalta, R.; Myhre, L.G.

    1988-07-01

    An open bilayer ground-crew chemical defense ensemble (CDE) was proposed to reduce the thermal burden during vapor-only exposure periods. This study compared the thermal-stress profile of the proposed ensemble to that produced by the currently employed closed CDE. Four subjects, alternating ensembles on separate days, walked on a treadmill in an environmental chamber at 5.3 km/h (3.3 mph) and 2% grade (an energy expenditure of 350 kcal/h) for alternating work/rest to achieve significant recovery. Mean total sweat production was lower (1.38 vs. 2.50 liters) and percent sweat evaporation greater (65.7% vs. 30.0%) in the prototype ensemble than in the CDE. The prototype ensemble provided greater heat dissipation and allowed more-efficient sweat evaporation which had the double benefit of reducing heat storage and limiting dehydration.

  16. 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

  17. 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.

  18. Polyphenol oxidase as a biochemical seed defense mechanism

    PubMed Central

    Fuerst, E. Patrick; Okubara, Patricia A.; Anderson, James V.; Morris, Craig F.

    2014-01-01

    Seed dormancy and resistance to decay are fundamental survival strategies, which allow a population of seeds to germinate over long periods of time. Seeds have physical, chemical, and biological defense mechanisms that protect their food reserves from decay-inducing organisms and herbivores. Here, we hypothesize that seeds also possess enzyme-based biochemical defenses, based on induction of the plant defense enzyme, polyphenol oxidase (PPO), when wild oat (Avena fatua L.) caryopses and seeds were challenged with seed-decaying Fusarium fungi. These studies suggest that dormant seeds are capable of mounting a defense response to pathogens. The pathogen-induced PPO activity from wild oat was attributed to a soluble isoform of the enzyme that appeared to result, at least in part, from proteolytic activation of a latent PPO isoform. PPO activity was also induced in wild oat hulls (lemma and palea), non-living tissues that cover and protect the caryopsis. These results are consistent with the hypothesis that seeds possess inducible enzyme-based biochemical defenses arrayed on the exterior of seeds and these defenses represent a fundamental mechanism of seed survival and longevity in the soil. Enzyme-based biochemical defenses may have broader implications since they may apply to other defense enzymes as well as to a diversity of plant species and ecosystems. PMID:25540647

  19. Suppression of a phospholipase D gene, OsPLDbeta1, activates defense responses and increases disease resistance in rice.

    PubMed

    Yamaguchi, Takeshi; Kuroda, Masaharu; Yamakawa, Hiromoto; Ashizawa, Taketo; Hirayae, Kazuyuki; Kurimoto, Leona; Shinya, Tomonori; Shibuya, Naoto

    2009-05-01

    Phospholipase D (PLD) plays an important role in plants, including responses to abiotic as well as biotic stresses. A survey of the rice (Oryza sativa) genome database indicated the presence of 17 PLD genes in the genome, among which OsPLDalpha1, OsPLDalpha5, and OsPLDbeta1 were highly expressed in most tissues studied. To examine the physiological function of PLD in rice, we made knockdown plants for each PLD isoform by introducing gene-specific RNA interference constructs. One of them, OsPLDbeta1-knockdown plants, showed the accumulation of reactive oxygen species in the absence of pathogen infection. Reverse transcription-polymerase chain reaction and DNA microarray analyses revealed that the knockdown of OsPLDbeta1 resulted in the up-/down-regulation of more than 1,400 genes, including the induction of defense-related genes such as pathogenesis-related protein genes and WRKY/ERF family transcription factor genes. Hypersensitive response-like cell death and phytoalexin production were also observed at a later phase of growth in the OsPLDbeta1-knockdown plants. These results indicated that the OsPLDbeta1-knockdown plants spontaneously activated the defense responses in the absence of pathogen infection. Furthermore, the OsPLDbeta1-knockdown plants exhibited increased resistance to the infection of major pathogens of rice, Pyricularia grisea and Xanthomonas oryzae pv oryzae. These results suggested that OsPLDbeta1 functions as a negative regulator of defense responses and disease resistance in rice. PMID:19286937

  20. Molecular emission in chemically active protostellar outflows

    NASA Astrophysics Data System (ADS)

    Lefloch, B.

    2011-12-01

    Protostellar outflows play an important role in the dynamical and chemical evolution of cloud through shocks. The Herschel Space Observatory (HSO) brings new insight both on the molecular content and the physical conditions in protostellar shocks through high spectral and angular resolution studies of the emission of major gas cooling agents and hydrides. The Herschel/CHESS key-program is carrying out an in depth study of the prototypical shock region L1157-B1. Analysis of the line profiles detected allows to constrain the formation/destruction route of various molecular species, in relation with the predictions of MHD shock models. The Herschel/WISH key-program investigates the properties and origin of water emission in a broad sample of protostellar outflows and envelopes. Implications of the first results for future studies on mass-loss phenomena are discussed.

  1. 47 CFR 0.181 - The Defense Commissioner.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... in public safety, homeland security, national security, emergency preparedness, disaster management..., Defense and Emergency Preparedness Functions § 0.181 The Defense Commissioner. The Defense Commissioner is... emergency preparedness, and defense activities of the Commission and has the following duties...

  2. 47 CFR 0.181 - The Defense Commissioner.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... in public safety, homeland security, national security, emergency preparedness, disaster management..., Defense and Emergency Preparedness Functions § 0.181 The Defense Commissioner. The Defense Commissioner is... emergency preparedness, and defense activities of the Commission and has the following duties...

  3. 47 CFR 0.181 - The Defense Commissioner.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... in public safety, homeland security, national security, emergency preparedness, disaster management..., Defense and Emergency Preparedness Functions § 0.181 The Defense Commissioner. The Defense Commissioner is... emergency preparedness, and defense activities of the Commission and has the following duties...

  4. 47 CFR 0.181 - The Defense Commissioner.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... in public safety, homeland security, national security, emergency preparedness, disaster management..., Defense and Emergency Preparedness Functions § 0.181 The Defense Commissioner. The Defense Commissioner is... emergency preparedness, and defense activities of the Commission and has the following duties...

  5. 47 CFR 0.181 - The Defense Commissioner.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... in public safety, homeland security, national security, emergency preparedness, disaster management..., Defense and Emergency Preparedness Functions § 0.181 The Defense Commissioner. The Defense Commissioner is... emergency preparedness, and defense activities of the Commission and has the following duties...

  6. 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

  7. 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

  8. 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

  9. Antipredator defenses predict diversification rates

    PubMed Central

    Arbuckle, Kevin; Speed, Michael P.

    2015-01-01

    The “escape-and-radiate” hypothesis predicts that antipredator defenses facilitate adaptive radiations by enabling escape from constraints of predation, diversified habitat use, and subsequently speciation. Animals have evolved diverse strategies to reduce the direct costs of predation, including cryptic coloration and behavior, chemical defenses, mimicry, and advertisement of unprofitability (conspicuous warning coloration). Whereas the survival consequences of these alternative defenses for individuals are well-studied, little attention has been given to the macroevolutionary consequences of alternative forms of defense. Here we show, using amphibians as the first, to our knowledge, large-scale empirical test in animals, that there are important macroevolutionary consequences of alternative defenses. However, the escape-and-radiate hypothesis does not adequately describe them, due to its exclusive focus on speciation. We examined how rates of speciation and extinction vary across defensive traits throughout amphibians. Lineages that use chemical defenses show higher rates of speciation as predicted by escape-and-radiate but also show higher rates of extinction compared with those without chemical defense. The effect of chemical defense is a net reduction in diversification compared with lineages without chemical defense. In contrast, acquisition of conspicuous coloration (often used as warning signals or in mimicry) is associated with heightened speciation rates but unchanged extinction rates. We conclude that predictions based on the escape-and-radiate hypothesis must incorporate the effect of traits on both speciation and extinction, which is rarely considered in such studies. Our results also suggest that knowledge of defensive traits could have a bearing on the predictability of extinction, perhaps especially important in globally threatened taxa such as amphibians. PMID:26483488

  10. 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.

  11. Fungal mitochondrial DNases: effectors with the potential to activate plant defenses in nonhost resistance.

    PubMed

    Hadwiger, Lee A; Polashock, James

    2013-01-01

    Previous reports on the model nonhost resistance interaction between Fusarium solani f. sp. phaseoli and pea endocarp tissue have described the disease resistance-signaling role of a fungal DNase1-like protein. The response resulted in no further growth beyond spore germination. This F. solani f. sp. phaseoli DNase gene, constructed with a pathogenesis-related (PR) gene promoter, when transferred to tobacco, generated resistance against Pseudomonas syringe pv. tabaci. The current analytical/theoretical article proposes similar roles for the additional nuclear and mitochondrial nucleases, the coding regions for which are identified in newly available fungal genome sequences. The amino acid sequence homologies within functional domains are conserved within a wide array of fungi. The potato pathogen Verticillium dahliae nuclease was divergent from that of the saprophyte, yeast; however, the purified DNase from yeast also elicited nonhost defense responses in pea, including pisatin accumulation, PR gene induction, and resistance against a true pea pathogen. The yeast mitochondrial DNase gene (open reading frame) predictably codes for a signal peptide providing the mechanism for secretion. Mitochondrial DNase genes appear to provide an unlimited source of components for developing transgenic resistance in all transformable plants. PMID:23228145

  12. 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.

  13. 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; Holton, Nicolas; Nekrasov, Vladimir; Ruan, Deling; Canlas, Patrick E.; Daudi, Arsalan; Petzold, Christopher J.; Singan, Vasanth R.; et al

    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

  14. Activation of TLR2 by a small molecule produced by Staphylococcus epidermidis increases antimicrobial defense against bacterial skin infections.

    PubMed

    Lai, Yuping; Cogen, Anna L; Radek, Katherine A; Park, Hyun Jeong; Macleod, Daniel T; Leichtle, Anke; Ryan, Allen F; Di Nardo, Anna; Gallo, Richard L

    2010-09-01

    Production of antimicrobial peptides by epithelia is an essential defense against infectious pathogens. In this study we evaluated whether the commensal microorganism Staphylococcus epidermidis may enhance production of antimicrobial peptides by keratinocytes and thus augment skin defense against infection. Exposure of cultured undifferentiated human keratinocytes to a sterile nontoxic small molecule of <10 kDa from S. epidermidis conditioned culture medium (SECM), but not similar preparations from other bacteria, enhanced human beta-defensin 2 (hBD2) and hBD3 mRNA expression and increased the capacity of cell lysates to inhibit the growth of group A Streptococcus (GAS) and S. aureus. Partial gene silencing of hBD3 inhibited this antimicrobial action. This effect was relevant in vivo as administration of SECM to mice decreased susceptibility to infection by GAS. Toll-like receptor 2 (TLR2) was important to this process as a TLR2-neutralizing antibody blocked induction of hBDs 2 and 3, and Tlr2-deficient mice did not show induction of mBD4. Taken together, these findings reveal a potential use for normal commensal bacterium S. epidermidis to activate TLR2 signaling and induce antimicrobial peptide expression, thus enabling the skin to mount an enhanced response to pathogens. PMID:20463690

  15. 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

  16. Induction of Nrf2-mediated cellular defenses and alteration of phase I activities as mechanisms of chemoprotective effects of coffee in the liver.

    PubMed

    Cavin, C; Marin-Kuan, M; Langouët, S; Bezençon, C; Guignard, G; Verguet, C; Piguet, D; Holzhäuser, D; Cornaz, R; Schilter, B

    2008-04-01

    Coffee consumption has been associated with a significant decrease in the risk of developing chronic diseases such as Parkinson disease, diabetes type-2 and several types of cancers (e.g. colon, liver). In the present study, a coffee-dependent induction of enzymes involved in xenobiotic detoxification processes was observed in rat liver and primary hepatocytes. In addition, coffee was found to induce the mRNA and protein expression of enzymes involved in cellular antioxidant defenses. These inductions were correlated with the activation of the Nrf2 transcription factor as shown using an ARE-reporter luciferase assay. The induction of detoxifying enzymes GSTs and AKR is compatible with a protection against both genotoxicity and cytotoxicity of aflatoxin B1 (AFB1). This hypothesis was confirmed in in vitro and ex vivo test systems, where coffee reduced both AFB1-DNA and protein adducts. Interestingly, coffee was also found to inhibit cytochrome CYP1A1/2, indicating that other mechanisms different from a stimulation of detoxification may also play a significant role in the chemoprotective effects of coffee. Further investigations in either human liver cell line and primary hepatocytes indicated that the chemoprotective effects of coffee against AFB1 genotoxicity are likely to be of relevance for humans. These data strongly suggest that coffee may protect against the adverse effects of AFB1. In addition, the coffee-mediated stimulation of the Nrf2-ARE pathway resulting in increased endogenous defense mechanisms against electrophilic but also oxidative insults further support that coffee may be associated with a protection against various types of chemical stresses.

  17. Induction of Nrf2-mediated cellular defenses and alteration of phase I activities as mechanisms of chemoprotective effects of coffee in the liver.

    PubMed

    Cavin, C; Marin-Kuan, M; Langouët, S; Bezençon, C; Guignard, G; Verguet, C; Piguet, D; Holzhäuser, D; Cornaz, R; Schilter, B

    2008-04-01

    Coffee consumption has been associated with a significant decrease in the risk of developing chronic diseases such as Parkinson disease, diabetes type-2 and several types of cancers (e.g. colon, liver). In the present study, a coffee-dependent induction of enzymes involved in xenobiotic detoxification processes was observed in rat liver and primary hepatocytes. In addition, coffee was found to induce the mRNA and protein expression of enzymes involved in cellular antioxidant defenses. These inductions were correlated with the activation of the Nrf2 transcription factor as shown using an ARE-reporter luciferase assay. The induction of detoxifying enzymes GSTs and AKR is compatible with a protection against both genotoxicity and cytotoxicity of aflatoxin B1 (AFB1). This hypothesis was confirmed in in vitro and ex vivo test systems, where coffee reduced both AFB1-DNA and protein adducts. Interestingly, coffee was also found to inhibit cytochrome CYP1A1/2, indicating that other mechanisms different from a stimulation of detoxification may also play a significant role in the chemoprotective effects of coffee. Further investigations in either human liver cell line and primary hepatocytes indicated that the chemoprotective effects of coffee against AFB1 genotoxicity are likely to be of relevance for humans. These data strongly suggest that coffee may protect against the adverse effects of AFB1. In addition, the coffee-mediated stimulation of the Nrf2-ARE pathway resulting in increased endogenous defense mechanisms against electrophilic but also oxidative insults further support that coffee may be associated with a protection against various types of chemical stresses. PMID:17976884

  18. Active disturbance rejection controller for chemical reactor

    SciTech Connect

    Both, Roxana; Dulf, Eva H.; Muresan, Cristina I.

    2015-03-10

    In the petrochemical industry, the synthesis of 2 ethyl-hexanol-oxo-alcohols (plasticizers alcohol) is of high importance, being achieved through hydrogenation of 2 ethyl-hexenal inside catalytic trickle bed three-phase reactors. For this type of processes the use of advanced control strategies is suitable due to their nonlinear behavior and extreme sensitivity to load changes and other disturbances. Due to the complexity of the mathematical model an approach was to use a simple linear model of the process in combination with an advanced control algorithm which takes into account the model uncertainties, the disturbances and command signal limitations like robust control. However the resulting controller is complex, involving cost effective hardware. This paper proposes a simple integer-order control scheme using a linear model of the process, based on active disturbance rejection method. By treating the model dynamics as a common disturbance and actively rejecting it, active disturbance rejection control (ADRC) can achieve the desired response. Simulation results are provided to demonstrate the effectiveness of the proposed method.

  19. Secretions from the ventral eversible gland of Spodoptera exigua caterpillars activate defense-related genes and induce emission of volatile organic compounds in tomato, Solanum lycopersicum

    PubMed Central

    2014-01-01

    Background Plant induced defense against herbivory are generally associated with metabolic costs that result in the allocation of photosynthates from growth and reproduction to the synthesis of defense compounds. Therefore, it is essential that plants are capable of sensing and differentiating mechanical injury from herbivore injury. Studies have shown that oral secretions (OS) from caterpillars contain elicitors of induced plant responses. However, studies that shows whether these elicitors originated from salivary glands or from other organs associated with feeding, such as the ventral eversible gland (VEG) are limited. Here, we tested the hypothesis that the secretions from the VEG gland of Spodoptera exigua caterpillars contain elicitors that induce plant defenses by regulating the expression of genes involved in the biosynthesis of volatile organic compounds (VOCs) and other defense-related genes. To test this hypothesis, we quantified and compared the activity of defense-related enzymes, transcript levels of defense-related genes and VOC emission in tomato plants damaged by S. exigua caterpillars with the VEG intact (VEGI) versus plants damaged by caterpillars with the VEG ablated (VEGA). Results The quantified defense-related enzymes (i.e. peroxidase, polyphenol oxidase, and lipoxigenase) were expressed in significantly higher amounts in plants damaged by VEGI caterpillars than in plants damaged by VEGA caterpillars. Similarly, the genes that encode for the key enzymes involved in the biosynthesis of jasmonic acid and terpene synthase genes that regulate production of terpene VOCs, were up-regulated in plants damaged by VEGI caterpillars. Moreover, the OS of VEGA caterpillars were less active in inducing the expression of defense genes in tomato plants. Increased emissions of VOCs were detected in the headspace of plants damaged by VEGI caterpillars compared to plants damaged by VEGA caterpillars. Conclusion These results suggest that the VEG of S. exigua

  20. Influence of Copper Nanoparticles on the Physical-Chemical Properties of Activated Sludge

    PubMed Central

    Chen, Hong; Zheng, Xiong; Chen, Yinguang; Li, Mu; Liu, Kun; Li, Xiang

    2014-01-01

    The physical-chemical properties of activated sludge, such as flocculating ability, hydrophobicity, surface charge, settleability, dewaterability and bacteria extracellular polymer substances (EPS), play vital roles in the normal operation of wastewater treatment plants (WWTPs). The nanoparticles released from commercial products will enter WWTPs and can induce potential adverse effects on activated sludge. This paper focused on the effects of copper nanoparticles (CuNPs) on these specific physical-chemical properties of activated sludge. It was found that most of these properties were unaffected by the exposure to lower CuNPs concentration (5 ppm), but different observation were made at higher CuNPs concentrations (30 and 50 ppm). At the higher CuNPs concentrations, the sludge surface charge increased and the hydrophobicity decreased, which were attributed to more Cu2+ ions released from the CuNPs. The carbohydrate content of EPS was enhanced to defense the toxicity of CuNPs. The flocculating ability was found to be deteriorated due to the increased cell surface charge, the decreased hydrophobicity, and the damaged cell membrane. The worsened flocculating ability made the sludge flocs more dispersed, which further increased the toxicity of the CuNPs by increasing the availability of the CuNPs to the bacteria present in the sludge. Further investigation indicated that the phosphorus removal efficiency decreased at higher CuNPs concentrations, which was consistent with the deteriorated physical-chemical properties of activated sludge. It seems that the physical-chemical properties can be used as an indicator for determining CuNPs toxicity to the bacteria in activated sludge. This work is important because bacteria toxicity effects to the activated sludge caused by nanoparticles may lead to the deteriorated treatment efficiency of wastewater treatment, and it is therefore necessary to find an easy way to indicate this toxicity. PMID:24663333

  1. Influence of copper nanoparticles on the physical-chemical properties of activated sludge.

    PubMed

    Chen, Hong; Zheng, Xiong; Chen, Yinguang; Li, Mu; Liu, Kun; Li, Xiang

    2014-01-01

    The physical-chemical properties of activated sludge, such as flocculating ability, hydrophobicity, surface charge, settleability, dewaterability and bacteria extracellular polymer substances (EPS), play vital roles in the normal operation of wastewater treatment plants (WWTPs). The nanoparticles released from commercial products will enter WWTPs and can induce potential adverse effects on activated sludge. This paper focused on the effects of copper nanoparticles (CuNPs) on these specific physical-chemical properties of activated sludge. It was found that most of these properties were unaffected by the exposure to lower CuNPs concentration (5 ppm), but different observation were made at higher CuNPs concentrations (30 and 50 ppm). At the higher CuNPs concentrations, the sludge surface charge increased and the hydrophobicity decreased, which were attributed to more Cu2+ ions released from the CuNPs. The carbohydrate content of EPS was enhanced to defense the toxicity of CuNPs. The flocculating ability was found to be deteriorated due to the increased cell surface charge, the decreased hydrophobicity, and the damaged cell membrane. The worsened flocculating ability made the sludge flocs more dispersed, which further increased the toxicity of the CuNPs by increasing the availability of the CuNPs to the bacteria present in the sludge. Further investigation indicated that the phosphorus removal efficiency decreased at higher CuNPs concentrations, which was consistent with the deteriorated physical-chemical properties of activated sludge. It seems that the physical-chemical properties can be used as an indicator for determining CuNPs toxicity to the bacteria in activated sludge. This work is important because bacteria toxicity effects to the activated sludge caused by nanoparticles may lead to the deteriorated treatment efficiency of wastewater treatment, and it is therefore necessary to find an easy way to indicate this toxicity.

  2. Active Emulsions: Synchronization of Chemical Oscillators

    NASA Astrophysics Data System (ADS)

    Fraden, Seth

    2012-02-01

    We explore the dynamical behavior of emulsions consisting of nanoliter volume droplets of the oscillatory Belousov-Zhabotinsky (BZ) reaction separated by a continuous oil phase. Some of the aqueous BZ reactants partition into the oil leading to chemical coupling of the drops. We use microfluidics to vary the size, composition and topology of the drops in 1D and 2D. Addition of a light sensitive catalyst to the drops and illumination with a computer projector allows each drop to be individually perturbed. A variety of synchronous regimes are found that systematically vary with the coupling strength and whether coupling is dominated by activatory or inhibitory species. In 1D we observe in- and anti-phase oscillations, stationary Turing patterns in which drops stop oscillating, but form spatially periodic patterns of drops in the oxidized and reduced states, and more complex combinations of stationary and oscillatory drops. In 2D, the attractors are more complex and vary with network topology and coupling strength. For hexagonal lattices as a function of increasing coupling strength we observe right and left handed rotating oscillations, mixed oscillatory and Turing states and finally full Turing states. Reaction -- diffusion models based on a simplified description of the BZ chemistry and diffusion of messenger species reproduce a number of the experimental results. For a range of parameters, a simplified phase oscillator model provides an intuitive understanding of the complex synchronization patterns. [4pt] ``Coupled oscillations in a 1D emulsion of Belousov--Zhabotinsky droplets,'' Jorge Delgado, Ning Li, Marcin Leda, Hector O. Gonzalez-Ochoa, Seth Fraden and Irving R. Epstein, Soft Matter, 7, 3155 (2011).

  3. Costs and benefits of priming for defense in Arabidopsis.

    PubMed

    van Hulten, Marieke; Pelser, Maaike; van Loon, L C; Pieterse, Corné M J; Ton, Jurriaan

    2006-04-01

    Induced resistance protects plants against a wide spectrum of diseases; however, it can also entail costs due to the allocation of resources or toxicity of defensive products. The cellular defense responses involved in induced resistance are either activated directly or primed for augmented expression upon pathogen attack. Priming for defense may combine the advantages of enhanced disease protection and low costs. In this study, we have compared the costs and benefits of priming to those of induced direct defense in Arabidopsis. In the absence of pathogen infection, chemical priming by low doses of beta-aminobutyric acid caused minor reductions in relative growth rate and had no effect on seed production, whereas induction of direct defense by high doses of beta-aminobutyric acid or benzothiadiazole strongly affected both fitness parameters. These costs were defense-related, because the salicylic acid-insensitive defense mutant npr1-1 remained unaffected by these treatments. Furthermore, the constitutive priming mutant edr1-1 displayed only slightly lower levels of fitness than wild-type plants and performed considerably better than the constitutively activated defense mutant cpr1-1. Hence, priming involves less fitness costs than induced direct defense. Upon infection by Pseudomonas syringae or Hyaloperonospora parasitica, priming conferred levels of disease protection that almost equaled the protection in benzothiadiazole-treated wild-type plants and cpr1 plants. Under these conditions, primed plants displayed significantly higher levels of fitness than noninduced plants and plants expressing chemically or cpr1-induced direct defense. Collectively, our results indicate that the benefits of priming-mediated resistance outweigh the costs in environments in which disease occurs.

  4. Effectiveness of ice-vest cooling in prolonging work tolerance time during heavy exercise in the heat for personnel wearing Canadian forces chemical defense ensembles

    SciTech Connect

    Bain, B.

    1991-01-01

    Effectiveness of a portable, ice-pack cooling vest (Steelevest) in prolonging work tolerance time in chemical defense clothing in the heat (33 C dry bulb, 33% relative humidity or 25 C WBGT) was evaluated while subjects exercised at a metabolic rate of approx. 700 watts. Subjects were six male volunteers. The protocol consisted of a 20 minute treadmill walk at 1.33 m/s. and 7.5% grade, followed by 15 minutes of a lifting task, 5 minutes rest, then another 20 minutes of lifting task for a total of one hour. The lifting task consisted of lifting of 20 kg box, carrying it 3 meters and setting it down. This was followed by a 6 m walk (3m back to the start point and 3 m back to the box) 15 sec after which the lifting cycle began again. The work was classified as heavy as previously defined. This protocol was repeated until the subjects were unable to continue or they reached a physiological endpoint. Time to voluntary cessation or physiological endpoint was called the work tolerance time. Physiological endpoints were rectal temperature of 39 C, heart rate exceeding 95% of maximum for two consecutive minutes or visible loss of motor control or nausea. The cooling vest had no effect on work tolerance time, rate of rise of rectal temperature or sweat loss. It was concluded that the Steelvest ice-vest is ineffective in prolonging work tolerance time and preventing increases in rectal temperature while wearing chemical protective clothing.

  5. 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

  6. Evaluation of chloropentafluorobenzene as an intake simulant for chemical defense training. Final report, October 1991-October 1992

    SciTech Connect

    Clewell, H.J.; Jarnot, B.M.

    1993-01-01

    For a number of years the U.S. Air Force has been performing research to develop safe intake simulants for chemical warfare agents (CWA) to provide accurate and quantitative real-time assessment of troop proficiency and gear efficacy during chemical warfare (CW) field exercises. Chloropentafluorobenzene (CPFB) was identified and evaluated as a candidate inhalation simulant, and was determined to possess desirable physiochemical and toxicological properties. These include rapid uptake, low metabolism and toxicity, rapid and predictable clearance, real-time detectability by existing portable 'breathalyzer' technology and by fielded CWA detectors, realistic canister breakthrough and commercial availability. A physiologically based pharmacokinetic (PBPK) model for CPEB has been developed which accurately describes the time course of blood and exhaled air concentrations during and following inhalation exposures of rats and primates to CPFB. This model has been employed to predict human exhaled air concentrations for several hours following brief CPFB exposures, such as might be experienced in training exercises using CPFB as an intake simulant. These simulants could be used to determine the exhaled air concentrations at which personnel would have been incapacitated had the exposure been to a real agent. The PBPK model was also used to calculate internal dose measures for a quantitative assessment of safe exposure criteria for the use of CPFB in such exercises. To assure the safety of personnel it is recommended that field exercises be designed to avoid exposures greater than 30 parts per million (ppm), with the daily (8 h) time-weighted average not to exceed 3 ppm. The exposure guideline should not impair use of CPFB since field analytical methods can measure CPFB.

  7. Active foraging for toxic prey during gestation in a snake with maternal provisioning of sequestered chemical defences

    PubMed Central

    Kojima, Yosuke; Mori, Akira

    2015-01-01

    Many animals sequester dietary defensive compounds and incorporate them into the offspring, which protects the young against predation. One possible but poorly investigated question is whether females of such species actively prey upon toxic diets. The snake Rhabdophis tigrinus sequesters defensive steroids from toads consumed as prey; it also feeds on other amphibians. Females produce chemically armed offspring in direct proportion to their own level of toad-derived toxins by provisioning the toxins to their eggs. Our field observations of movements and stomach contents of radio-tracked R. tigrinus showed that gravid snakes preyed upon toads by actively foraging in the habitat of toads, even though toads were a scarce resource and toad-searching may incur potential costs. Our Y-maze experiments demonstrated that gravid females were more likely to trail the chemical cues of toads than were males or non-gravid females. These results showed behavioural switching in females and active foraging for scarce, toxic prey during gestation. Because exploitation of toads by gravid females results in their offspring being more richly endowed with prey-derived toxins, active foraging for toxic prey is expected to be an adaptive antipredator trait, which may enhance chemical defence in offspring. PMID:25392472

  8. Annual report to Congress. Department of Energy activities relating to the Defense Nuclear Facilities Safety Board, calendar year 2000

    SciTech Connect

    2001-03-01

    This Annual Report to the Congress describes the Department of Energy's activities in response to formal recommendations and other interactions with the Defense Nuclear Facilities Safety Board. During 2000, the Department completed its implementation and proposed closure of one Board recommendation and completed all implementation plan milestones associated with two additional Board recommendations. Also in 2000, the Department formally accepted two new Board recommendations and developed implementation plans in response to those recommendations. The Department also made significant progress with a number of broad-based safety initiatives. These include initial implementation of integrated safety management at field sites and within headquarters program offices, issuance of a nuclear safety rule, and continued progress on stabilizing excess nuclear materials to achieve significant risk reduction.

  9. Parallel activities and interactions between antimicrobial peptides and complement in host defense at the airway epithelial surface.

    PubMed

    Hiemstra, Pieter S

    2015-11-01

    Antimicrobial peptides and complement components contribute to host defense as well as inflammation and tissue injury in the respiratory tract. The airway epithelial surface is the main site of action of these immune effectors, and airway epithelial cells contribute markedly to their local production. Whereas both antimicrobial peptides and complement display overlapping functions, it is increasingly clear that both effector mechanisms also interact. Furthermore, excessive or uncontrolled release of antimicrobial peptides as well as complement activation may contribute to inflammatory lung diseases. Therefore, further knowledge of interactions between these systems may provide more insight into the pathogenesis of a range of lung diseases. In this review, recent findings on the functions, collaborations and other interactions between antimicrobial peptides and complement are discussed with a specific focus on the airway epithelium.

  10. Effects of the chemical-defense antidote atropine sulfate on helicopter-pilot performance: A simulator study. Final report

    SciTech Connect

    Simmons, F.R.; Caldwell, J.A.; Stephens, R.L.; Stone, L.W.; Carter, D.J.

    1989-07-01

    Atropine is fielded as an antidote for organophosphate poisoning where chemical nerve agents are used. However, inappropriate self-injection may lead to anticholinergic side effects detrimental to aviators in flight. To determine the scope and magnitude of these possible side effects, 12 male Army helicopter pilots in good health flew several missions in a helicopter simulator after being injected (I.M.) with either a placebo or 2mg or 4mg of atropine sulfate. Physiological effects essentially followed the classical model. The 2 mg dose of atropine caused small degradations on some of laboratory-collected measures, but often did not produce effects, which differed significantly from those produced by a placebo dose. A 4mg dose of atropine, however, exerted a variety of statistically significant effects upon flight performance, contrast sensitivity, cognitive performance, tracking accuracy, and cortical evoked responses. The flight performance evaluations (both subjective and objective) showed statistically significant changes in the subject's abilities to fly the simulator. Results obtained from other tasks in the study suggest, further, the decrements in flight performance resulted from a slowing of both information processing and psychomotor performance. Atropine effects were not of sufficient magnitude to preclude further research under actual flight conditions.

  11. Regeneration of complex oil-gland secretions and its importance for chemical defense in an oribatid mite.

    PubMed

    Heethoff, Michael

    2012-09-01

    Most oribatid mites possess a pair of opisthonotal exocrine glands that produce mostly complex, species-specific secretions. Such blends may contain more than 10 different compounds, but hardly anything is known about their primary biosynthesis or regeneration. I analyzed recovery of the 6 main components from the 11-compound secretion of the oribatid mite Archegozetes longisetosus Aoki, including the main chemical classes hydrocarbons, aromatics, and terpenes, during a 20-day time course after complete gland depletion. About 10 % of the original total secretion amount was restored after 24 hr, and after 2-6 days, the amount had reached the range of total amount observed in the control group. Most compounds were recovered at similar rates within the first 48 hr. An important exception was pentadecane, which was predominantly produced in the first few hours, suggesting that this compound is the main solvent of the secretion. Although relative amounts of the main compounds differed significantly over time, the complex profile of the whole secretion was stable and not confidently distinguishable among the sampling dates. The general recovery rate was high during the first 48 hr, about 25 times higher than in the remaining 18 days. The biological importance of this high initial investment was supported by predation experiments: the predacious rove beetle Stenus juno was first repelled after 48 hr when at least 25 % of secretions was restored.

  12. AFLATOXIN B2: CHEMICAL IDENTITY AND BIOLOGICAL ACTIVITY.

    PubMed

    CHANG, S B; ABDEL-KADER, M M; WICK, E L; WOGAN, G N

    1963-11-29

    Aflatoxin B(2), a blue-fluorescent metabolite of Aspergillus flavus, was isolated from cultures grown on crushed wheat. Chemical structure of the compound was elucidated as dihydroaflatoxin B(1). Biological activity was determined in day-old male white Pekin ducklings. The criteria of activity were reduction in growth and liver size and the extent of bile-duct hyperplasia.

  13. Changes in thyroid peroxidase activity in response to various chemicals.

    PubMed

    Song, Mee; Kim, Youn-Jung; Park, Yong-Keun; Ryu, Jae-Chun

    2012-08-01

    Thyroperoxidase (TPO) is a large heme-containing glycoprotein that catalyzes the transfer of iodine to thyroglobulin during thyroid hormone (TH) synthesis. Previously, we established an in vitro assay for TPO activity based on human recombinant TPO (hrTPO) stably transfected into human follicular thyroid carcinoma (FTC-238) cells. It is important to determine whether environmental chemicals can disrupt TPO activity because it is an important factor in the TH axis. In this study, we used our assay to examine the changes in TPO activity in response to various chemicals, including benzophenones (BPs), polycyclic aromatic hydrocarbons (PAHs), and persistent organic pollutants (POPs). Overall, BPs, PAHs, and POPs slightly altered TPO activity at low doses, as compared with the positive controls methimazole (MMI), genistein, and 2,2',4,4'-tetrahydroxy BP. Benzophenone, benzhydrol, 3-methylchloranthracene, pyrene, benzo(k)fluoranthene, benzo(e)pyrene, perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), and heptachlor decreased TPO activity, while 2,4-dihydroxy BP, 2,2'-dihydroxy-4-methoxy BP, and dibenzo(a,h)anthracene increased TPO activity. From these data, we can predict the disruption of TPO activity by various chemicals as a sensitive TH end point. TPO activity should be considered when enacting measures to regulate environmental exposure to thyroid-disrupting chemicals. PMID:22699773

  14. Spontaneous and specific activation of chemical bonds in macromolecular fluids.

    PubMed

    Park, Insun; Shirvanyants, David; Nese, Alper; Matyjaszewski, Krzysztof; Rubinstein, Michael; Sheiko, Sergei S

    2010-09-01

    Mechanical activation of chemical bonds typically involves the application of external forces, which implies a broad distribution of bond tensions. We demonstrate that controlling the flow profile of a macromolecular fluid generates and delineates mechanical force concentration, enabling a hierarchical activation of chemical bonds on different length scales from the macroscopic to the molecular. Bond tension is spontaneously generated within brushlike macromolecules as they spread on a solid substrate. The molecular architecture creates an uneven distribution of tension in the covalent bonds, leading to spatially controlled bond scission. By controlling the flow rate and the gradient of the film pressure, one can sever the flowing macromolecules with high precision. Specific chemical bonds are activated within distinct macromolecules located in a defined area of a thin film. Furthermore, the flow-controlled loading rate enables quantitative analysis of the bond activation parameters.

  15. Coordinated Activation of Programmed Cell Death and Defense Mechanisms in Transgenic Tobacco Plants Expressing a Bacterial Proton Pump.

    PubMed Central

    Mittler, R.; Shulaev, V.; Lam, E.

    1995-01-01

    In plants, programmed cell death is thought to be activated during the hypersensitive response to certain avirulent pathogens and in the course of several differentiation processes. We describe a transgenic model system that mimics the activation of programmed cell death in higher plants. In this system, expression of a bacterial proton pump in transgenic tobacco plants activates a cell death pathway that may be similar to that triggered by recognition of an incompatible pathogen. Thus, spontaneous lesions that resemble hypersensitive response lesions are formed, multiple defense mechanisms are apparently activated, and systemic resistance is induced in the absence of a pathogen. Interestingly, mutation of a single amino acid in the putative channel of this proton pump renders it inactive with respect to lesion formation and induction of resistance to pathogen challenge. This transgenic model system may provide insights into the mechanisms involved in mediating cell death in higher plants. In addition, it may also be used as a general agronomic tool to enhance disease protection. PMID:12242350

  16. Guiding Catalytically Active Particles with Chemically Patterned Surfaces

    NASA Astrophysics Data System (ADS)

    Uspal, W. E.; Popescu, M. N.; Dietrich, S.; Tasinkevych, M.

    2016-07-01

    Catalytically active Janus particles suspended in solution create gradients in the chemical composition of the solution along their surfaces, as well as along any nearby container walls. The former leads to self-phoresis, while the latter gives rise to chemiosmosis, providing an additional contribution to self-motility. Chemiosmosis strongly depends on the molecular interactions between the diffusing chemical species and the wall. We show analytically, using an approximate "point-particle" approach, that by chemically patterning a planar substrate one can direct the motion of Janus particles: the induced chemiosmotic flows can cause particles to either "dock" at the chemical step between the two materials or follow a chemical stripe. These theoretical predictions are confirmed by full numerical calculations. Generically, docking occurs for particles which tend to move away from their catalytic caps, while stripe following occurs in the opposite case. Our analysis reveals the physical mechanisms governing this behavior.

  17. 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. PMID:16479545

  18. 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.

  19. 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.

  20. Combined activation of the energy and cellular-defense pathways may explain the potent anti-senescence activity of methylene blue

    PubMed Central

    Atamna, Hani; Atamna, Wafa; Al-Eyd, Ghaith; Shanower, Gregory; Dhahbi, Joseph M.

    2015-01-01

    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. PMID:26386875

  1. Unbalanced activation of glutathione metabolic pathways suggests potential involvement in plant defense against the gall midge Mayetiola destructor in wheat.

    PubMed

    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

  2. Lipase Activity in Insect Oral Secretions Mediates Defense Responses in Arabidopsis1[C][W][OA

    PubMed Central

    Schäfer, Martin; Fischer, Christine; Meldau, Stefan; Seebald, Eileen; Oelmüller, Ralf; Baldwin, Ian T.

    2011-01-01

    How plants perceive herbivory is not yet well understood. We investigated early responses of the model plant Arabidopsis (Arabidopsis thaliana) to attack from the generalist grasshopper herbivore, Schistocerca gregaria (Caelifera). When compared with wounding alone, S. gregaria attack and the application of grasshopper oral secretions (GS) to puncture wounds elicited a rapid accumulation of various oxylipins, including 13-hydroperoxy octadecatrienoic acid, 12-oxo-phytodienoic acid (OPDA), jasmonic acid, and jasmonic acid-isoleucine. Additionally, GS increased cytosolic calcium levels, mitogen-activated protein kinase (MPK3 and MPK6) activity, and ethylene emission but not the accumulation of hydrogen peroxide. Although GS contain caeliferin A16:0, a putative elicitor of caeliferan herbivores, treatment with pure, synthetic caeliferin A16:0 did not induce any of the observed responses. With mutant plants, we demonstrate that the observed changes in oxylipin levels are independent of MPK3 and MPK6 activity but that MPK6 is important for the GS-induced ethylene release. Biochemical and pharmacological analyses revealed that the lipase activity of GS plays a central role in the GS-induced accumulation of oxylipins, especially OPDA, which could be fully mimicked by treating puncture wounds only with a lipase from Rhizopus arrhizus. GS elicitation increased the levels of OPDA-responsive transcripts. Because the oral secretions of most insects used to study herbivory-induced responses in Arabidopsis rapidly elicit similar accumulations of OPDA, we suggest that lipids containing OPDA (arabidopsides) play an important role in the activation of herbivory-induced responses. PMID:21546453

  3. Quantitative genetic activity graphical profiles for use in chemical evaluation

    SciTech Connect

    Waters, M.D.; Stack, H.F.; Garrett, N.E.; Jackson, M.A.

    1990-12-31

    A graphic approach, terms a Genetic Activity Profile (GAP), was developed to display a matrix of data on the genetic and related effects of selected chemical agents. The profiles provide a visual overview of the quantitative (doses) and qualitative (test results) data for each chemical. Either the lowest effective dose or highest ineffective dose is recorded for each agent and bioassay. Up to 200 different test systems are represented across the GAP. Bioassay systems are organized according to the phylogeny of the test organisms and the end points of genetic activity. The methodology for producing and evaluating genetic activity profile was developed in collaboration with the International Agency for Research on Cancer (IARC). Data on individual chemicals were compiles by IARC and by the US Environmental Protection Agency (EPA). Data are available on 343 compounds selected from volumes 1-53 of the IARC Monographs and on 115 compounds identified as Superfund Priority Substances. Software to display the GAPs on an IBM-compatible personal computer is available from the authors. Structurally similar compounds frequently display qualitatively and quantitatively similar profiles of genetic activity. Through examination of the patterns of GAPs of pairs and groups of chemicals, it is possible to make more informed decisions regarding the selection of test batteries to be used in evaluation of chemical analogs. GAPs provided useful data for development of weight-of-evidence hazard ranking schemes. Also, some knowledge of the potential genetic activity of complex environmental mixtures may be gained from an assessment of the genetic activity profiles of component chemicals. The fundamental techniques and computer programs devised for the GAP database may be used to develop similar databases in other disciplines. 36 refs., 2 figs.

  4. 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.

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

    PubMed

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

    2016-02-01

    Goatpox, caused by goatpox virus (GTPV), is one of the most serious infectious diseases associated with high morbidity and mortality in goats. However, little is known about involvement of host innate immunity during the GTPV infection. For this, goats were experimentally infected with GTPV. The results showed that GTPV infection significantly induced mRNA expression of type I interferon (IFN)-α and IFN-β in peripheral blood lymphocytes, spleen and lung. In addition, GTPV infection enhanced expression of several inflammatory cytokines, including interleukin (IL)-1β, IL-6, IL-18; and tumor necrosis factor-α (TNF-α). Strikingly, infection with GTPV activated signal transducers and activators of transcription 3 (STAT3), a critical cytokine signaling molecule. Interestingly, the virus infection induced expression of suppressor of cytokine signaling (SOCS)-1. Importantly, the infection resulted in an increased expression of some critical interferon-stimulated genes, such as interferon-induced transmembrane protein (IFITM) 1, IFITM3, interferon stimulated gene (ISG) 15 and ISG20. Furthermore, we found that infection with GTPV up-regulated expression of Toll-like receptor (TLR) 2 and TLR9. These results revealed that GTPV infection activated host innate immune signaling and thereby triggered antiviral innate immunity. The findings provide novel insights into complex mechanisms underlying GTPV-host interaction and pathogenesis of GTPV. PMID:26850535

  6. 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. PMID:21927839

  7. 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.

  8. The circadian clock regulates rhythmic activation of the NRF2/glutathione-mediated antioxidant defense pathway to modulate pulmonary fibrosis

    PubMed Central

    Pekovic-Vaughan, Vanja; Gibbs, Julie; Yoshitane, Hikari; Yang, Nan; Pathiranage, Dharshika; Guo, Baoqiang; Sagami, Aya; Taguchi, Keiko; Bechtold, David; Loudon, Andrew; Yamamoto, Masayuki; Chan, Jefferson; van der Horst, Gijsbertus T.J.; Fukada, Yoshitaka; Meng, Qing-Jun

    2014-01-01

    The disruption of the NRF2 (nuclear factor erythroid-derived 2-like 2)/glutathione-mediated antioxidant defense pathway is a critical step in the pathogenesis of several chronic pulmonary diseases and cancer. While the mechanism of NRF2 activation upon oxidative stress has been widely investigated, little is known about the endogenous signals that regulate the NRF2 pathway in lung physiology and pathology. Here we show that an E-box-mediated circadian rhythm of NRF2 protein is essential in regulating the rhythmic expression of antioxidant genes involved in glutathione redox homeostasis in the mouse lung. Using an in vivo bleomycin-induced lung fibrosis model, we reveal a clock “gated” pulmonary response to oxidative injury, with a more severe fibrotic effect when bleomycin was applied at a circadian nadir in NRF2 levels. Timed administration of sulforaphane, an NRF2 activator, significantly blocked this phenotype. Moreover, in the lungs of the arrhythmic ClockΔ19 mice, the levels of NRF2 and the reduced glutathione are constitutively low, associated with increased protein oxidative damage and a spontaneous fibrotic-like pulmonary phenotype. Our findings reveal a pivotal role for the circadian control of the NRF2/glutathione pathway in combating oxidative/fibrotic lung damage, which might prompt new chronotherapeutic strategies for the treatment of human lung diseases, including idiopathic pulmonary fibrosis. PMID:24637114

  9. Chemical constituents, antimicrobial and antimalarial activities of Zanthoxylum monophyllum.

    PubMed

    Rodríguez-Guzmán, Raquel; Fulks, Laura C Johansmann; Radwan, Mohamed M; Burandt, Charles L; Ross, Samir A

    2011-09-01

    From the leaves and bark of Zanthoxylum monophyllum, a new lignan, 3-methoxy-3',4'-methylenedioxylignan-4,8,9,9'-tetraol (1), has been isolated along with 22 known compounds (2- 23), fifteen of them reported for the first time from Z. monophyllum. Their chemical structures were elucidated using detailed spectroscopic studies and chemical analysis. All compounds were evaluated for antimicrobial and antiprotozoal activities. Alkaloids BIS-[6-(5,6-dihydro-chelerythrinyl)] ether (2) and 6-ethoxy-chelerythrine (4) exhibited strong activity against Aspergillus fumigatus and methicillin-resistant Staphylococcus aureus (MRSA). Compound 4-methoxy-N-methyl-2-quinolone (9) exhibited significant activity against MRSA (IC50 value of 8.0 µM) while compound 5,8,4'-trihydroxy-3,7,3'-trimethoxyflavone (10) showed weak activity against Plasmodium falciparum.

  10. Onset of herbivore-induced resistance in systemic tissue primed for jasmonate-dependent defenses is activated by abscisic acid

    PubMed Central

    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. PMID:24416038

  11. Chemical Components and Cardiovascular Activities of Valeriana spp.

    PubMed Central

    Chen, Heng-Wen; Wei, Ben-Jun; He, Xuan-Hui; Liu, Yan; Wang, Jie

    2015-01-01

    Valeriana spp. is a flowering plant that is well known for its essential oils, iridoid compounds such as monoterpenes and sesquiterpenes, flavonoids, alkaloids, amino acids, and lignanoids. Valeriana spp. exhibits a wide range of biological activities such as lowering blood pressure and heart rate, antimyocardial ischemia reperfusion injury, antiarrhythmia, and regulation of blood lipid levels. This review focuses on the chemical constituents and cardiovascular activities of Valeriana spp. PMID:26788113

  12. Bioorthogonal Chemical Activation of Kinases in Living Systems

    PubMed Central

    2016-01-01

    Selective manipulation of protein kinases under living conditions is highly desirable yet extremely challenging, particularly in a gain-of-function fashion. Here we employ our recently developed bioorthogonal cleavage reaction as a general strategy for intracellular activation of individual kinases. Site-specific incorporation of trans-cyclooctene-caged lysine in place of the conserved catalytic lysine, in conjunction with the cleavage partner dimethyl-tetrazine, allowed efficient lysine decaging with the kinase activity chemically rescued in living systems. PMID:27280167

  13. Total Chemical Synthesis of Biologically Active Vascular Endothelial Growth Factor

    SciTech Connect

    Mandal, Kalyaneswar; Kent, Stephen B.H.

    2011-09-15

    The 204-residue covalent-dimer vascular endothelial growth factor (VEGF, see picture) with full mitogenic activity was prepared from three unprotected peptide segments by one-pot native chemical ligations. The covalent structure of the synthetic VEGF was confirmed by precise mass measurement, and the three-dimensional structure of the synthetic protein was determined by high-resolution X-ray crystallography.

  14. 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

  15. Antibacterial activity of Turkish propolis and its qualitative and quantitative chemical composition.

    PubMed

    Popova, M; Silici, S; Kaftanoglu, O; Bankova, V

    2005-03-01

    The antibacterial activity of propolis from different regions of Turkey was studied, accompanied by TLC and GC-MS analyses of its chemical composition and spectrophotometric quantification of the most important active principles. All six samples were active against the bacterial test strains used; however, samples 1 (Yozgat), 2 (Izmir) and 3 (Kayseri) were more active than samples 4 (Adana), 5 (Erzurum) and 6 (Artvin). By TLC comparison all samples were found to contain poplar taxonomic markers but in samples 4 (Adana), 5 (Erzurum) and 6 (Artvin), different substances were observed, which were not present in P. nigra L. bud exudate. The typical poplar samples 1 (Yozgat), 2 (Izmir) and 3 (Kayseri) displayed very similar phenolic and flavonoid content. Samples 4 (Adana), 5 (Erzurum) and 6 (Artvin) were characterized by low phenolic and very low flavonoid concentrations. Qualitative analysis by GC-MS revealed that sample 4 (Adana) contained diterpenic acids and high percent of cinnamyl cinnamate, sample 5 (Erzurum)-significant amounts of hydroxy fatty acids and triterpenic alcohoLs, and sample 6 (Artvin)-phenolic glycerides, characteristic for the bud exudate of Populus euphratica Oliv. The results confirm the importance of phenolics for propolis antibacterial activity, and the significance of P. nigra L. as a propolis source, which provides the hive with the best defense against microorganisms.

  16. Identification of Synthetic Host Defense Peptide Mimics That Exert Dual Antimicrobial and Anti-Inflammatory Activities

    PubMed Central

    Som, Abhigyan; Navasa, Nicolás; Percher, Avital; Scott, Richard W.

    2012-01-01

    A group of synthetic antimicrobial oligomers, inspired by naturally occurring antimicrobial peptides, were analyzed for the ability to modulate innate immune responses to Toll-like receptor (TLR) ligands. These synthetic mimics of antimicrobial peptides (SMAMPs) specifically reduced cytokine production in response to Staphylococcus aureus and the S. aureus component lipoteichoic acid (LTA), a TLR2 agonist. Anti-inflammatory SMAMPs prevented the induction of tumor necrosis factor (TNF), interleukin 6 (IL-6), and IL-10 in response to S. aureus or LTA, but no other TLR2 ligands. We show that these SMAMPs bind specifically to LTA in vitro and prevent its interaction with TLR2. Importantly, the SMAMP greatly reduced the induction of TNF and IL-6 in vivo in mice acutely infected with S. aureus while simultaneously reducing bacterial loads dramatically (4 log10). Thus, these SMAMPs can eliminate the damage induced by pathogen-associated molecular patterns (PAMPs) while simultaneously eliminating infection in vivo. They are the first known SMAMPs to demonstrate anti-inflammatory and antibacterial activities in vivo. PMID:22956655

  17. Detection of Neural Activity in the Brains of Japanese Honeybee Workers during the Formation of a “Hot Defensive Bee Ball”

    PubMed Central

    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. PMID:22431987

  18. Structure activity relationships to assess new chemicals under TSCA

    SciTech Connect

    Auletta, A.E.

    1990-12-31

    Under Section 5 of the Toxic Substances Control Act (TSCA), manufacturers must notify the US Environmental Protection Agency (EPA) 90 days before manufacturing, processing, or importing a new chemical substance. This is referred to as a premanufacture notice (PMN). The PMN must contain certain information including chemical identity, production volume, proposed uses, estimates of exposure and release, and any health or environmental test data that are available to the submitter. Because there is no explicit statutory authority that requires testing of new chemicals prior to their entry into the market, most PMNs are submitted with little or no data. As a result, EPA has developed special techniques for hazard assessment of PMN chemicals. These include (1) evaluation of available data on the chemical itself, (2) evaluation of data on analogues of the PMN, or evaluation of data on metabolites or analogues of metabolites of the PMN, (3) use of quantitative structure activity relationships (QSARs), and (4) knowledge and judgement of scientific assessors in the interpretation and integration of the information developed in the course of the assessment. This approach to evaluating potential hazards of new chemicals is used to identify those that are most in need of addition review of further testing. It should not be viewed as a replacement for testing. 4 tabs.

  19. Duodenal Chemosensing and Mucosal Defenses

    PubMed Central

    Akiba, Yasutada; Kaunitz, Jonathan D.

    2011-01-01

    The duodenal mucosa is exposed to endogenous and exogenous chemicals, including acid, CO2, bile acids and nutrients. Mucosal chemical sensors are necessary to exert physiological responses such as secretion, digestion, absorption, and motility. We propose a mucosal chemosensing system by which luminal chemicals are sensed via mucosal acid sensors and G-protein-coupled receptors. Luminal acid/CO2 sensing consists of ecto- and cytosolic carbonic anhydrases, epithelial ion transporters, and acid sensors expressed on the afferent nerves in the duodenum. Furthermore, a luminal L-glutamate signal is mediated via mucosal L-glutamate receptors, including metabotropic glutamate receptors and taste receptor 1 family heterodimers, with activation of afferent nerves and cyclooxygenase, whereas luminal Ca2+ is differently sensed via the calcium-sensing receptor in the duodenum. Recent studies also show the involvement of enteroendocrine G-protein-coupled receptors in bile acid and fatty acid sensing in the duodenum. These luminal chemosensors help activate mucosal defense mechanisms in or- der to maintain the mucosal integrity and physiological responses. Stimulation of luminal chemosensing in the duodenal mucosa may prevent mucosal injury, affect nutrient metabolism, and modulate sensory nerve activity. PMID:21389725

  20. A nanosized Ag-silica hybrid complex prepared by γ-irradiation activates the defense response in Arabidopsis

    NASA Astrophysics Data System (ADS)

    Chu, Hyosub; Kim, Hwa-Jung; Su Kim, Joong; Kim, Min-Soo; Yoon, Byung-Dae; Park, Hae-Jun; Kim, Cha Young

    2012-02-01

    Silver nanoparticles have antimicrobial activity against many pathogenic microbes. Here, the preparation of a nanosized Ag-silica hybrid complex (NSS) prepared by γ-irradiation is described. The effects of both NSS and reduced Ag nanoparticles (Ag 0) on the growth of the model plant Arabidopsis thaliana were tested. The application of 1-10 ppm NSS complex improved Arabidopsis growth in soil, whereas 100 ppm NSS resulted in weakly curled leaves. In addition, supplementation of Murashige and Skoog (MS) growth medium with 1 ppm NSS promoted the root growth of Arabidopsis seedlings, but root growth was inhibited by supplementation with 10 ppm NSS. To investigate whether the NSS complex could induce plant defense responses, the expression of pathogenesis-related ( PR) genes that are implicated in systemic acquired resistance (SAR) in Arabidopsis plants was examined. PR1, PR2 and PR5 were significantly up-regulated by each application of 10 ppm NSS complex or Ag 0 to the rosette leaves. Furthermore, pretreatment with the NSS complex induced more pathogen resistance to the virulent pathogen Pseudomonas syringae pv. tomato DC3000 ( Pst) compared to water treatment in Arabidopsis plants.

  1. 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.

  2. Reactive oxygen and nitrogen species in defense/stress responses activated by chitosan in sycamore cultured cells.

    PubMed

    Malerba, Massimo; Cerana, Raffaella

    2015-01-29

    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.

  3. Reactive oxygen and nitrogen species in defense/stress responses activated by chitosan in sycamore cultured cells.

    PubMed

    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

  4. Chemical constituents of Solanum coagulans and their antimicrobial activities.

    PubMed

    Qin, Xu-Jie; Lunga, Paul-Keilah; Zhao, Yun-Li; Liu, Ya-Ping; Luo, Xiao-Dong

    2016-04-01

    The present study aimed at determining the chemical constituents of Solanum coagulans and their antimicrobial activities. The compounds were isolated by various chromatographic techniques and their structures were elucidated on the basis of extensive spectroscopic analysis, chemical methods, and comparison with reported spectroscopic data. One new phenolic glycoside, methyl salicylate 2-O-β-D-glucopyranosyl-(1→2)-β-D-glucopyranoside (1), together with 12 known compounds (2-13), were isolated from the aerial parts of Solanum coagulans. Compound 1 was a new phenolic glycoside, and 2-6 were isolated from Solanum genus for the first time. The antimicrobial activities of the isolated compounds were also evaluated. Compound 7 showed remarkable antifungal activity against T. mentagrophytes, M. gypseum and E. floccosum with MIC values being 3.13, 1.56 and 3.13 μg·mL(-1), respectively. PMID:27114320

  5. Constitutively Active Mitogen-Activated Protein Kinase Versions Reveal Functions of Arabidopsis MPK4 in Pathogen Defense Signaling[C][W

    PubMed Central

    Berriri, Souha; Garcia, Ana Victoria; dit Frey, Nicolas Frei; Rozhon, Wilfried; Pateyron, Stéphanie; Leonhardt, Nathalie; Montillet, Jean-Luc; Leung, Jeffrey; Hirt, Heribert; Colcombet, Jean

    2012-01-01

    Plant mitogen-activated protein kinases (MAPKs) are involved in important processes, including stress signaling and development. In a functional yeast screen, we identified mutations that render Arabidopsis thaliana MAPKs constitutively active (CA). Importantly, CA-MAPKs maintain their specificity toward known activators and substrates. As a proof-of-concept, Arabidopsis MAPK4 (MPK4) function in plant immunity was investigated. In agreement with the phenotype of mpk4 mutants, CA-MPK4 plants were compromised in pathogen-induced salicylic acid accumulation and disease resistance. MPK4 activity was found to negatively regulate pathogen-associated molecular pattern-induced reactive oxygen species production but had no impact on callose deposition, indicating that CA-MPK4 allows discriminating between processes regulated by MPK4 activity from processes indirectly affected by mpk4 mutation. Finally, MPK4 activity was also found to compromise effector-triggered immunity conditioned by the Toll Interleukin-1 Receptor–nucleotide binding (NB)–Leu-rich repeat (LRR) receptors RPS4 and RPP4 but not by the coiled coil–NB-LRR receptors RPM1 and RPS2. Overall, these data reveal important insights on how MPK4 regulates plant defenses and establishes that CA-MAPKs offer a powerful tool to analyze the function of plant MAPK pathways. PMID:23115249

  6. Guiding catalytically active particles with chemically patterned surfaces

    NASA Astrophysics Data System (ADS)

    Uspal, William; Popescu, Mihail; Dietrich, Siegfried; Tasinkevych, Mykola

    Catalytically active Janus particles in solution create gradients in the chemical composition of the solution along their surfaces, as well as along any nearby container walls. The former leads to self-phoresis, while the latter gives rise to chemi-osmosis, providing an additional contribution to self-motility. Chemi-osmosis strongly depends on the molecular interactions between the diffusing chemical species and the wall. We show analytically, using an approximate ``point-particle'' approach, that by chemically patterning a planar substrate (e.g., by adsorbing two different materials) one can direct the motion of Janus particles: the induced chemi-osmotic flows can cause particles to either ``dock'' at a chemical step between the two materials, or to follow a chemical stripe. These theoretical predictions are confirmed by full numerical calculations. Generically, docking occurs for particles which tend to move away from their catalytic caps, while stripe-following occurs in the opposite case. Our analysis reveals the physical mechanisms governing this behavior.

  7. Mining Chemical Activity Status from High-Throughput Screening Assays

    PubMed Central

    Soufan, Othman; Ba-alawi, Wail; Afeef, Moataz; Essack, Magbubah; Rodionov, Valentin; Kalnis, Panos; Bajic, Vladimir B.

    2015-01-01

    High-throughput screening (HTS) experiments provide a valuable resource that reports biological activity of numerous chemical compounds relative to their molecular targets. Building computational models that accurately predict such activity status (active vs. inactive) in specific assays is a challenging task given the large volume of data and frequently small proportion of active compounds relative to the inactive ones. We developed a method, DRAMOTE, to predict activity status of chemical compounds in HTP activity assays. For a class of HTP assays, our method achieves considerably better results than the current state-of-the-art-solutions. We achieved this by modification of a minority oversampling technique. To demonstrate that DRAMOTE is performing better than the other methods, we performed a comprehensive comparison analysis with several other methods and evaluated them on data from 11 PubChem assays through 1,350 experiments that involved approximately 500,000 interactions between chemicals and their target proteins. As an example of potential use, we applied DRAMOTE to develop robust models for predicting FDA approved drugs that have high probability to interact with the thyroid stimulating hormone receptor (TSHR) in humans. Our findings are further partially and indirectly supported by 3D docking results and literature information. The results based on approximately 500,000 interactions suggest that DRAMOTE has performed the best and that it can be used for developing robust virtual screening models. The datasets and implementation of all solutions are available as a MATLAB toolbox online at www.cbrc.kaust.edu.sa/dramote and can be found on Figshare. PMID:26658480

  8. Anti-inflammatory activity and chemical profile of Galphimia glauca.

    PubMed

    González-Cortazar, Manasés; Herrera-Ruiz, Maribel; Zamilpa, Alejandro; Jiménez-Ferrer, Enrique; Marquina, Silvia; Alvarez, Laura; Tortoriello, Jaime

    2014-01-01

    Galphimia glauca, commonly known as "flor de estrella", is a plant species used in Mexican traditional medicine for the treatment of different diseases that have an acute or chronic inflammatory process in common. Aerial parts of this plant contain nor-seco-triterpenoids with anxiolytic properties, which have been denominated galphimines. Other compounds identified in the plant are tetragalloyl-quinic acid, gallic acid, and quercetin, which are able to inhibit the bronchial obstruction induced by platelet-activating factor. The objective of this work was to evaluate the anti-inflammatory effect of crude extracts from G. glauca and, by means of bioguided chemical separation, to identify the compounds responsible for this pharmacological activity. n-Hexane, ethyl acetate, dichloromethane, and methanol extracts showed an important anti-inflammatory effect. Chemical separation of the active methanol extract allowed us to identify the nor-seco-triterpenes galphimine-A (1) and galphimine-E (3) as the anti-inflammatory principles. Analysis of structure-activity relationships evidenced that the presence of an oxygenated function in C6 is absolutely necessary to show activity. In this work, the isolation and structural elucidation of two new nor-seco-triterpenes denominated as galphimine-K (4) and galphimine-L (5), together with different alkanes, fatty acids, as well as three flavonoids (17-19), are described, to our knowledge for the first time, from Galphimia glauca.

  9. Biologically active LIL proteins built with minimal chemical diversity

    PubMed Central

    Heim, Erin N.; Marston, Jez L.; Federman, Ross S.; Edwards, Anne P. B.; Karabadzhak, Alexander G.; Petti, Lisa M.; Engelman, Donald M.; DiMaio, Daniel

    2015-01-01

    We have constructed 26-amino acid transmembrane proteins that specifically transform cells but consist of only two different amino acids. Most proteins are long polymers of amino acids with 20 or more chemically distinct side-chains. The artificial transmembrane proteins reported here are the simplest known proteins with specific biological activity, consisting solely of an initiating methionine followed by specific sequences of leucines and isoleucines, two hydrophobic amino acids that differ only by the position of a methyl group. We designate these proteins containing leucine (L) and isoleucine (I) as LIL proteins. These proteins functionally interact with the transmembrane domain of the platelet-derived growth factor β-receptor and specifically activate the receptor to transform cells. Complete mutagenesis of these proteins identified individual amino acids required for activity, and a protein consisting solely of leucines, except for a single isoleucine at a particular position, transformed cells. These surprisingly simple proteins define the minimal chemical diversity sufficient to construct proteins with specific biological activity and change our view of what can constitute an active protein in a cellular context. PMID:26261320

  10. Insect-gene-activity detection system for chemical and biological warfare agents and toxic industrial chemicals

    NASA Astrophysics Data System (ADS)

    Mackie, Ryan S.; Schilling, Amanda S.; Lopez, Arturo M.; Rayms-Keller, Alfredo

    2002-02-01

    Detection of multiple chemical and biological weapons (CBW) agents and/or complex mixtures of toxic industrial chemicals (TIC) is imperative for both the commercial and military sectors. In a military scenario, a multi-CBW attack would create confusion, thereby delaying decontamination and therapeutic efforts. In the commercial sector, polluted sites invariably contain a mixture of TIC. Novel detection systems capable of detecting CBW and TIC are sorely needed. While it may be impossible to build a detector capable of discriminating all the possible combinations of CBW, a detection system capable of statistically predicting the most likely composition of a given mixture is within the reach of current emerging technologies. Aquatic insect-gene activity may prove to be a sensitive, discriminating, and elegant paradigm for the detection of CBW and TIC. We propose to systematically establish the expression patterns of selected protein markers in insects exposed to specific mixtures of chemical and biological warfare agents to generate a library of biosignatures of exposure. The predicting capabilities of an operational library of biosignatures of exposures will allow the detection of emerging novel or genetically engineered agents, as well as complex mixtures of chemical and biological weapons agents. CBW and TIC are discussed in the context of war, terrorism, and pollution.

  11. 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

    cellular anti-oxidant defense capacity through activation of Nrf2/HO-1, thereby protecting C2C12 myoblasts from H2O2-induced oxidative cytotoxicity. PMID:27280051

  12. STRUCTURE-ACTIVITY RELATIONSHIP STUIDES AND THEIR ROLE IN PREDICTING AND INVESTIGATING CHEMICAL TOXICITY

    EPA Science Inventory

    Structure-Activity Relationship Studies and their Role in Predicting and Investigating Chemical Toxicity

    Structure-activity relationships (SAR) represent attempts to generalize chemical information relative to biological activity for the twin purposes of generating insigh...

  13. TGA Transcription Factors Activate the Salicylic Acid-Suppressible Branch of the Ethylene-Induced Defense Program by Regulating ORA59 Expression.

    PubMed

    Zander, Mark; Thurow, Corinna; Gatz, Christiane

    2014-07-01

    Salicylic acid (SA), a hormone essential for defense against biotrophic pathogens, triggers increased susceptibility of plants against necrotrophic attackers by suppressing the jasmonic acid-ethylene (ET) defense response. Here, we show that this disease-promoting SA effect is abolished in plants lacking the three related TGACG sequence-specific binding proteins TGA2, TGA5, and TGA6 (class II TGAs). After treatment of plants with the ET precursor 1-aminocyclopropane-1-carboxylic acid (ACC), activation of all those genes that are suppressed by SA depended on class II TGAs. Rather than TGA binding sites, GCC-box motifs were significantly enriched in the corresponding promoters. GCC-box motifs are recognized by members of the superfamily of APETALA2/ETHYLENE RESPONSE FACTORs (ERFs). Of 11 activating ACC-induced APETALA2/ERFs, only ORA59 (for OCTADECANOID-RESPONSIVE ARABIDOPSIS APETALA2/ETHYLENE RESPONSE FACTOR domain protein59) and ERF96 were strongly suppressed by SA. ORA59 is the master regulator of the jasmonic acid-ET-induced defense program. ORA59 transcript levels do not reach maximal levels in the tga2 tga5 tga6 triple mutant, and this residual activity cannot be suppressed by SA. The ORA59 promoter contains an essential TGA binding site and is a direct target of class II TGAs as revealed by chromatin immunoprecipitation experiments. We suggest that class II TGAs at the ORA59 promoter constitute an important regulatory hub for the activation and SA suppression of ACC-induced genes.

  14. TGA Transcription Factors Activate the Salicylic Acid-Suppressible Branch of the Ethylene-Induced Defense Program by Regulating ORA59 Expression1[C][W

    PubMed Central

    Zander, Mark; Thurow, Corinna; Gatz, Christiane

    2014-01-01

    Salicylic acid (SA), a hormone essential for defense against biotrophic pathogens, triggers increased susceptibility of plants against necrotrophic attackers by suppressing the jasmonic acid-ethylene (ET) defense response. Here, we show that this disease-promoting SA effect is abolished in plants lacking the three related TGACG sequence-specific binding proteins TGA2, TGA5, and TGA6 (class II TGAs). After treatment of plants with the ET precursor 1-aminocyclopropane-1-carboxylic acid (ACC), activation of all those genes that are suppressed by SA depended on class II TGAs. Rather than TGA binding sites, GCC-box motifs were significantly enriched in the corresponding promoters. GCC-box motifs are recognized by members of the superfamily of APETALA2/ETHYLENE RESPONSE FACTORs (ERFs). Of 11 activating ACC-induced APETALA2/ERFs, only ORA59 (for OCTADECANOID-RESPONSIVE ARABIDOPSIS APETALA2/ETHYLENE RESPONSE FACTOR domain protein59) and ERF96 were strongly suppressed by SA. ORA59 is the master regulator of the jasmonic acid-ET-induced defense program. ORA59 transcript levels do not reach maximal levels in the tga2 tga5 tga6 triple mutant, and this residual activity cannot be suppressed by SA. The ORA59 promoter contains an essential TGA binding site and is a direct target of class II TGAs as revealed by chromatin immunoprecipitation experiments. We suggest that class II TGAs at the ORA59 promoter constitute an important regulatory hub for the activation and SA suppression of ACC-induced genes. PMID:24989234

  15. 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.

  16. CHEMICAL EFFECTS ON OYSTER (CRASSOSTREA VIRGINICA) HEMOCYTE MICROBICIDAL ACTIVITY

    EPA Science Inventory

    Oyster (Crassostrea virginica) hemocytes, or blood cells, perform important internal defense functions such as phagocytosis and intracellular destruction of pathogens and bacteria. Using techniques such as phagocytosis and chemiluminescence assays, potential impairment of hemocyt...

  17. Sila-fulleranes: promising chemically active fullerene analogs

    NASA Astrophysics Data System (ADS)

    Marsusi, Farah; Qasemnazhand, Mohammad

    2016-07-01

    Density-functional theory (DFT) was applied to investigate the geometry and electronic properties of bare Si60 and H-terminated Si-fullerene. DFT predicts outward sites on a bare Si60 cage. By using π-orbital axis analysis (POAV), it is shown that these sites result from a strong tendency of silicon atoms to form sp3 hybridization bonds. Natural bond orbital (NBO) analysis confirms the sp3 hybridization nature of Si-Si bonds in Si-fulleranes. The quantum confinement effect (QCE) does not affect band gap (BG) so strongly in the size between 1 and 1.7 nm. In contrast, the geometry and symmetry of the cage have a significant influence on the BG. In contrast to their carbon analogs, pentagon rings increase the stability of the cages. Functionalized Si-cages are stable and can be chemically very active. The electronic properties are highly sensitive to the surface chemistry via functionalization with different chemical groups. As a result, BGs and chemical activities of these cages can be drastically tuned through the chemistry of the surface.

  18. Sila-fulleranes: promising chemically active fullerene analogs

    NASA Astrophysics Data System (ADS)

    Marsusi, Farah; Qasemnazhand, Mohammad

    2016-07-01

    Density-functional theory (DFT) was applied to investigate the geometry and electronic properties of bare Si60 and H-terminated Si-fullerene. DFT predicts outward sites on a bare Si60 cage. By using π-orbital axis analysis (POAV), it is shown that these sites result from a strong tendency of silicon atoms to form sp3 hybridization bonds. Natural bond orbital (NBO) analysis confirms the sp3 hybridization nature of Si–Si bonds in Si-fulleranes. The quantum confinement effect (QCE) does not affect band gap (BG) so strongly in the size between 1 and 1.7 nm. In contrast, the geometry and symmetry of the cage have a significant influence on the BG. In contrast to their carbon analogs, pentagon rings increase the stability of the cages. Functionalized Si-cages are stable and can be chemically very active. The electronic properties are highly sensitive to the surface chemistry via functionalization with different chemical groups. As a result, BGs and chemical activities of these cages can be drastically tuned through the chemistry of the surface.

  19. Sila-fulleranes: promising chemically active fullerene analogs.

    PubMed

    Marsusi, Farah; Qasemnazhand, Mohammad

    2016-07-01

    Density-functional theory (DFT) was applied to investigate the geometry and electronic properties of bare Si60 and H-terminated Si-fullerene. DFT predicts outward sites on a bare Si60 cage. By using π-orbital axis analysis (POAV), it is shown that these sites result from a strong tendency of silicon atoms to form sp(3) hybridization bonds. Natural bond orbital (NBO) analysis confirms the sp(3) hybridization nature of Si-Si bonds in Si-fulleranes. The quantum confinement effect (QCE) does not affect band gap (BG) so strongly in the size between 1 and 1.7 nm. In contrast, the geometry and symmetry of the cage have a significant influence on the BG. In contrast to their carbon analogs, pentagon rings increase the stability of the cages. Functionalized Si-cages are stable and can be chemically very active. The electronic properties are highly sensitive to the surface chemistry via functionalization with different chemical groups. As a result, BGs and chemical activities of these cages can be drastically tuned through the chemistry of the surface. PMID:27240656

  20. 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

  1. 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

  2. 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

  3. Influences of chemical activators on incinerator bottom ash.

    PubMed

    Qiao, X C; Cheeseman, C R; Poon, C S

    2009-02-01

    This research has applied different chemical activators to mechanically and thermally treated fine fraction (<14 mm) of incinerator bottom ash (IBA), in order to investigate the influences of chemical activators on this new pozzolanic material. IBA has been milled and thermally treated at 800 degrees C (TIBA). The TIBA produced was blended with Ca(OH)(2) and evaluated for setting time, reactivity and compressive strength after the addition of 0.0565 mole of Na(2)SO(4), K(2)SO(4), Na(2)CO(3), K(2)CO(3), NaOH, KOH and CaCl(2) into 100g of binder (TIBA+Ca(OH)(2)). The microstructures of activated IBA and hydrated samples have been characterized by X-ray diffraction (XRD) and thermogravimetry (TG) analysis. Thermal treatment is found to produce gehlenite (Ca(2)Al(2)SiO(7)), wollastonite (CaSiO(3)) and mayenite (Ca(12)Al(14)O(33)) phases. The thermally treated IBA samples are significantly more reactive than the milled IBA. The addition of Na(2)CO(3) can increase the compressive strength and calcium hydroxide consumption at 28-day curing ages. However, the addition of Na(2)SO(4), K(2)SO(4), K(2)CO(3), NaOH and KOH reduces the strength and hydration reaction. Moreover, these chemicals produce more porous samples due to increased generation of hydrogen gas. The addition of CaCl(2) has a negative effect on the hydration of TIBA samples. Calcium aluminium oxide carbonate sulphide hydrate (Ca(4)Al(2)O(6)(CO(3))(0.67)(SO(3))(0.33)(H(2)O)(11)) is the main hydration product in the samples with activated IBA, except for the sample containing CaCl(2). PMID:18718749

  4. Influences of chemical activators on incinerator bottom ash.

    PubMed

    Qiao, X C; Cheeseman, C R; Poon, C S

    2009-02-01

    This research has applied different chemical activators to mechanically and thermally treated fine fraction (<14 mm) of incinerator bottom ash (IBA), in order to investigate the influences of chemical activators on this new pozzolanic material. IBA has been milled and thermally treated at 800 degrees C (TIBA). The TIBA produced was blended with Ca(OH)(2) and evaluated for setting time, reactivity and compressive strength after the addition of 0.0565 mole of Na(2)SO(4), K(2)SO(4), Na(2)CO(3), K(2)CO(3), NaOH, KOH and CaCl(2) into 100g of binder (TIBA+Ca(OH)(2)). The microstructures of activated IBA and hydrated samples have been characterized by X-ray diffraction (XRD) and thermogravimetry (TG) analysis. Thermal treatment is found to produce gehlenite (Ca(2)Al(2)SiO(7)), wollastonite (CaSiO(3)) and mayenite (Ca(12)Al(14)O(33)) phases. The thermally treated IBA samples are significantly more reactive than the milled IBA. The addition of Na(2)CO(3) can increase the compressive strength and calcium hydroxide consumption at 28-day curing ages. However, the addition of Na(2)SO(4), K(2)SO(4), K(2)CO(3), NaOH and KOH reduces the strength and hydration reaction. Moreover, these chemicals produce more porous samples due to increased generation of hydrogen gas. The addition of CaCl(2) has a negative effect on the hydration of TIBA samples. Calcium aluminium oxide carbonate sulphide hydrate (Ca(4)Al(2)O(6)(CO(3))(0.67)(SO(3))(0.33)(H(2)O)(11)) is the main hydration product in the samples with activated IBA, except for the sample containing CaCl(2).

  5. Chemical activation of a food deprivation signal extends lifespan.

    PubMed

    Lucanic, Mark; Garrett, Theo; Yu, Ivan; Calahorro, Fernando; Asadi Shahmirzadi, Azar; Miller, Aaron; Gill, Matthew S; Hughes, Robert E; Holden-Dye, Lindy; Lithgow, Gordon J

    2016-10-01

    Model organisms subject to dietary restriction (DR) generally live longer. Accompanying this lifespan extension are improvements in overall health, based on multiple metrics. This indicates that pharmacological treatments that mimic the effects of DR could improve health in humans. To find new chemical structures that extend lifespan, we screened 30 000 synthetic, diverse drug-like chemicals in Caenorhabditis elegans and identified several structurally related compounds that acted through DR mechanisms. The most potent of these NP1 impinges upon a food perception pathway by promoting glutamate signaling in the pharynx. This results in the overriding of a GPCR pathway involved in the perception of food and which normally acts to decrease glutamate signals. Our results describe the activation of a dietary restriction response through the pharmacological masking of a novel sensory pathway that signals the presence of food. This suggests that primary sensory pathways may represent novel targets for human pharmacology. PMID:27220516

  6. 76 FR 64960 - Extension of Agency Information Collection Activity Under OMB Review: Flight Crew Self-Defense...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-19

    ..., 2011 (76 FR 27656). Upon registering for a voluntary advanced self-defense training class provided by TSA, the collection process involves requesting, the name, contact information, airline employee... are flight and cabin crew members of a U.S. airline conducting scheduled passenger operations. As...

  7. 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…

  8. Pereskia aculeata Muller (Cactaceae) Leaves: Chemical Composition and Biological Activities

    PubMed Central

    Souza, Lucèia Fàtima; Caputo, Lucia; Inchausti De Barros, Ingrid Bergman; Fratianni, Florinda; Nazzaro, Filomena; De Feo, Vincenzo

    2016-01-01

    The aims of this work were to study the chemical composition of the essential oil from the leaves of Pereskia aculeata and to evaluate some biological activities of three leaf extracts. The phenolic content, antioxidant activity, and in vitro antimicrobial and antifungal activities were determined. The methanol extract showed antioxidant activity (EC50 7.09 mg/mL) and high polyphenols content (15.04 ± 0.31 mg gallic acid equivalents (GAE)/g). The petroleum ether extract exhibited potent antibacterial activity against Escherichia coli, whereas the chloroform extract showed inhibitory activity against Bacillus cereus and Staphylococcus aureus. The petroleum ether and methanol extracts were more effective in inhibiting the growth of Aspergillus versicolor. The possible cytotoxicity of extracts on neuroblastoma SH-SY5Y cancer cell line and the influence on adenylate cyclase (ADCY) expression was also studied. P. aculeata chloroform extract showed antiproliferative activity with an IC50 value of 262.83 µg/mL. Treatments of SH-SY5Y neuroblastoma cells with 100 µg/mL of methanol extract significantly reduced ADCY1 expression. PMID:27598154

  9. Pereskia aculeata Muller (Cactaceae) Leaves: Chemical Composition and Biological Activities.

    PubMed

    Souza, Lucèia Fàtima; Caputo, Lucia; Inchausti De Barros, Ingrid Bergman; Fratianni, Florinda; Nazzaro, Filomena; De Feo, Vincenzo

    2016-01-01

    The aims of this work were to study the chemical composition of the essential oil from the leaves of Pereskia aculeata and to evaluate some biological activities of three leaf extracts. The phenolic content, antioxidant activity, and in vitro antimicrobial and antifungal activities were determined. The methanol extract showed antioxidant activity (EC50 7.09 mg/mL) and high polyphenols content (15.04 ± 0.31 mg gallic acid equivalents (GAE)/g). The petroleum ether extract exhibited potent antibacterial activity against Escherichia coli, whereas the chloroform extract showed inhibitory activity against Bacillus cereus and Staphylococcus aureus. The petroleum ether and methanol extracts were more effective in inhibiting the growth of Aspergillus versicolor. The possible cytotoxicity of extracts on neuroblastoma SH-SY5Y cancer cell line and the influence on adenylate cyclase (ADCY) expression was also studied. P. aculeata chloroform extract showed antiproliferative activity with an IC50 value of 262.83 µg/mL. Treatments of SH-SY5Y neuroblastoma cells with 100 µg/mL of methanol extract significantly reduced ADCY1 expression. PMID:27598154

  10. 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…

  11. Chemical Signaling and Functional Activation in Colloidosome-Based Protocells.

    PubMed

    Sun, Shiyong; Li, Mei; Dong, Faqin; Wang, Shengjie; Tian, Liangfei; Mann, Stephen

    2016-04-13

    An aqueous-based microcompartmentalized model involving the integration of partially hydrophobic Fe(III)-rich montmorillonite (FeM) clay particles as structural and catalytic building blocks for colloidosome membrane assembly, self-directed membrane remodeling, and signal-induced protocell communication is described. The clay colloidosomes exhibit size- and charge-selective permeability, and show dual catalytic functions involving spatially confined enzyme-mediated dephosphorylation and peroxidase-like membrane activity. The latter is used for the colloidosome-mediated synthesis and assembly of a temperature-responsive poly(N-isopropylacrylamide)(PNIPAM)/clay-integrated hybrid membrane. In situ PNIPAM elaboration of the membrane is coupled to a glucose oxidase (GOx)-mediated signaling pathway to establish a primitive model of chemical communication and functional activation within a synthetic "protocell community" comprising a mixed population of GOx-containing silica colloidosomes and alkaline phosphatase (ALP)-containing FeM-clay colloidosomes. Triggering the enzyme reaction in the silica colloidosomes gives a hydrogen peroxide signal that induces polymer wall formation in a coexistent population of the FeM-clay colloidosomes, which in turn generates self-regulated membrane-gated ALP-activity within the clay microcompartments. The emergence of new functionalities in inorganic colloidosomes via chemical communication between different protocell populations provides a first step toward the realization of interacting communities of synthetic functional microcompartments. PMID:26923794

  12. Regular Wave Propagation Out of Noise in Chemical Active Media

    SciTech Connect

    Alonso, S.; Sendina-Nadal, I.; Perez-Munuzuri, V.; Sancho, J. M.; Sagues, F.

    2001-08-13

    A pacemaker, regularly emitting chemical waves, is created out of noise when an excitable photosensitive Belousov-Zhabotinsky medium, strictly unable to autonomously initiate autowaves, is forced with a spatiotemporal patterned random illumination. These experimental observations are also reproduced numerically by using a set of reaction-diffusion equations for an activator-inhibitor model, and further analytically interpreted in terms of genuine coupling effects arising from parametric fluctuations. Within the same framework we also address situations of noise-sustained propagation in subexcitable media.

  13. Heterogeneity in signaled active avoidance learning: substantive and methodological relevance of diversity in instrumental defensive responses to threat cues

    PubMed Central

    Galatzer-Levy, Isaac R.; Moscarello, Justin; Blessing, Esther M.; Klein, JoAnna; Cain, Christopher K.; LeDoux, Joseph E.

    2014-01-01

    Individuals exposed to traumatic stressors follow divergent patterns including resilience and chronic stress. However, researchers utilizing animal models that examine learned or instrumental threat responses thought to have translational relevance for Posttraumatic Stress Disorder (PTSD) and resilience typically use central tendency statistics that assume population homogeneity. This approach potentially overlooks fundamental differences that can explain human diversity in response to traumatic stressors. The current study tests this assumption by identifying and replicating common heterogeneous patterns of response to signaled active avoidance (AA) training. In this paradigm, rats are trained to prevent an aversive outcome (shock) by performing a learned instrumental behavior (shuttling between chambers) during the presentation of a conditioned threat cue (tone). We test the hypothesis that heterogeneous trajectories of threat avoidance provide more accurate model fit compared to a single mean trajectory in two separate studies. Study 1 conducted 3 days of signaled AA training (n = 81 animals) and study 2 conducted 5 days of training (n = 186 animals). We found that four trajectories in both samples provided the strongest model fit. Identified populations included animals that acquired and retained avoidance behavior on the first day (Rapid Avoiders: 22 and 25%); those who never successfully acquired avoidance (Non-Avoiders; 20 and 16%); a modal class who acquired avoidance over 3 days (Modal Avoiders; 37 and 50%); and a population who demonstrated a slow pattern of avoidance, failed to fully acquire avoidance in study 1 and did acquire avoidance on days 4 and 5 in study 2 (Slow Avoiders; 22.0 and 9%). With the exception of the Slow Avoiders in Study 1, populations that acquired demonstrated rapid step-like increases leading to asymptotic levels of avoidance. These findings indicate that avoidance responses are heterogeneous in a way that may be informative for

  14. Nanomaterials for Defense Applications

    NASA Astrophysics Data System (ADS)

    Turaga, Uday; Singh, Vinitkumar; Lalagiri, Muralidhar; Kiekens, Paul; Ramkumar, Seshadri S.

    Nanotechnology has found a number of applications in electronics and healthcare. Within the textile field, applications of nanotechnology have been limited to filters, protective liners for chemical and biological clothing and nanocoatings. This chapter presents an overview of the applications of nanomaterials such as nanofibers and nanoparticles that are of use to military and industrial sectors. An effort has been made to categorize nanofibers based on the method of production. This chapter particularly focuses on a few latest developments that have taken place with regard to the application of nanomaterials such as metal oxides in the defense arena.

  15. Chemical and mechanical defenses vary among maternal lines and leaf ages in Verbascum thapsus L. (Scrophulariaceae) and reduce palatability to a generalist insect

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Intra-specific variation in host-plant quality affects herbivore foraging decisions and, because of this, can feed back to shape plant fitness. In particular, among- and within plant variation in defense shapes herbivore behavior, and if genetically based, may respond to natural selection by herbivo...

  16. ER Quality Control Components UGGT and STT3a Are Required for Activation of Defense Responses in Bir1-1

    PubMed Central

    Zhang, Qian; Sun, Tongjun; Zhang, Yuelin

    2015-01-01

    The receptor-like kinase SUPPRESSOR OF BIR1, 1 (SOBIR1) functions as a critical regulator in plant immunity. It is required for activation of cell death and defense responses in Arabidopsis bak1-interacting receptor-like kinase 1,1 (bir1-1) mutant plants. Here we report that the ER quality control component UDP-glucose:glycoprotein glucosyltransferase (UGGT) is required for the biogenesis of SOBIR1 and mutations in UGGT suppress the spontaneous cell death and constitutive defense responses in bir1-1. Loss of function of STT3a, which encodes a subunit of the oligosaccharyltransferase complex, also suppresses the autoimmune phenotype in bir1-1. However, it has no effect on the accumulation of SOBIR1, suggesting that additional signaling components other than SOBIR1 may be regulated by ER quality control. Our study provides clear evidence that ER quality control play critical roles in regulating defense activation in bir1-1. PMID:25775181

  17. Lipophilic defenses from Alcyonium soft corals of Antarctica.

    PubMed

    Núñez-Pons, Laura; Carbone, Marianna; Vázquez, Jennifer; Gavagnin, Margherita; Avila, Conxita

    2013-05-01

    Alcyonacean soft corals lack physical or skeletal defenses and their nematocyst system is weak, leading to the conclusion that soft corals mainly rely on chemistry for protection from predators and microbes. Defensive chemicals of primary and secondary metabolic origin are exuded in the mucus surface layer, explaining the general lack of heavy fouling and predation in corals. In Antarctic ecosystems, where generalist predation is intense and mainly driven by invertebrate consumers, the genus Alcyonium is represented by eight species. Our goal was to investigate the understudied chemical ecology of Antarctic Alcyonium soft corals. We obtained six samples belonging to five species: A. antarcticum, A. grandis, A. haddoni, A. paucilobulatum, and A. roseum, and assessed the lipid-soluble fractions for the presence of defensive agents in these specimens. Ethyl ether extracts were tested in feeding bioassays with the sea star Odontaster validus and the amphipod Cheirimedon femoratus as putative sympatric predators. Repellent activities were observed towards both consumers in all but one of the samples assessed. Moreover, three of the extracts caused inhibition to a sympatric marine bacterium. The ether extracts afforded characteristic illudalane sesquiterpenoids in two of the samples, as well as particular wax esters subfractions in all the colonies analyzed. Both kinds of metabolites displayed significant deterrent activities demonstrating their likely defensive role. These results suggest that lipophilic chemicals are a first line protection strategy in Antarctic Alcyonium soft corals against predation and bacterial fouling.

  18. Active membrane having uniform physico-chemically functionalized ion channels

    DOEpatents

    Gerald, II, Rex E; Ruscic, Katarina J; Sears, Devin N; Smith, Luis J; Klingler, Robert J; Rathke, Jerome W

    2012-09-24

    The present invention relates to a physicochemically-active porous membrane for electrochemical cells that purports dual functions: an electronic insulator (separator) and a unidirectional ion-transporter (electrolyte). The electrochemical cell membrane is activated for the transport of ions by contiguous ion coordination sites on the interior two-dimensional surfaces of the trans-membrane unidirectional pores. One dimension of the pore surface has a macroscopic length (1 nm-1000 .mu.m) and is directed parallel to the direction of an electric field, which is produced between the cathode and the anode electrodes of an electrochemical cell. The membrane material is designed to have physicochemical interaction with ions. Control of the extent of the interactions between the ions and the interior pore walls of the membrane and other materials, chemicals, or structures contained within the pores provides adjustability of the ionic conductivity of the membrane.

  19. Chemical activation of the mechanotransduction channel Piezo1

    PubMed Central

    Syeda, Ruhma; Xu, Jie; Dubin, Adrienne E; Coste, Bertrand; Mathur, Jayanti; Huynh, Truc; Matzen, Jason; Lao, Jianmin; Tully, David C; Engels, Ingo H; Petrassi, H Michael; Schumacher, Andrew M; Montal, Mauricio; Bandell, Michael; Patapoutian, Ardem

    2015-01-01

    Piezo ion channels are activated by various types of mechanical stimuli and function as biological pressure sensors in both vertebrates and invertebrates. To date, mechanical stimuli are the only means to activate Piezo ion channels and whether other modes of activation exist is not known. In this study, we screened ∼3.25 million compounds using a cell-based fluorescence assay and identified a synthetic small molecule we termed Yoda1 that acts as an agonist for both human and mouse Piezo1. Functional studies in cells revealed that Yoda1 affects the sensitivity and the inactivation kinetics of mechanically induced responses. Characterization of Yoda1 in artificial droplet lipid bilayers showed that Yoda1 activates purified Piezo1 channels in the absence of other cellular components. Our studies demonstrate that Piezo1 is amenable to chemical activation and raise the possibility that endogenous Piezo1 agonists might exist. Yoda1 will serve as a key tool compound to study Piezo1 regulation and function. DOI: http://dx.doi.org/10.7554/eLife.07369.001 PMID:26001275

  20. 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

  1. Food-grade argan oil supplementation in molasses enhances fermentative performance and antioxidant defenses of active dry wine yeast.

    PubMed

    Gamero-Sandemetrio, Esther; Torrellas, Max; Rábena, María Teresa; Gómez-Pastor, Rocío; Aranda, Agustín; Matallana, Emilia

    2015-12-01

    The tolerance of the yeast Saccharomyces cerevisiae to desiccation is important for the use of this microorganism in the wine industry, since active dry yeast (ADY) is routinely used as starter for must fermentations. Both biomass propagation and dehydration cause cellular oxidative stress, therefore negatively affecting yeast performance. Protective treatments against oxidative damage, such as natural antioxidants, may have important biotechnological implications. In this study we analysed the antioxidant capacity of pure chemical compounds (quercetin, ascorbic acid, caffeic acid, oleic acid, and glutathione) added to molasses during biomass propagation, and we determine several oxidative damage/response parameters (lipid peroxidation, protein carbonylation, protective metabolites and enzymatic activities) to assess their molecular effects. Supplementation with ascorbic, caffeic or oleic acids diminished the oxidative damage associated to ADY production. Based on these results, we tested supplementation of molasses with argan oil, a natural food-grade ingredient rich in these three antioxidants, and we showed that it improved both biomass yield and fermentative performance of ADY. Therefore, we propose the use of natural, food-grade antioxidant ingredients, such as argan oil, in industrial processes involving high cellular oxidative stress, such as the biotechnological production of the dry starter.

  2. Biological activities and chemical composition of lichens from Serbia

    PubMed Central

    Kosanic, Marijana; Rankovic, Branislav; Stanojkovic, Tatjana; Vasiljevic, Perica; Manojlovic, Nedeljko

    2014-01-01

    The aim of this study is to investigate chemical composition of acetone extracts of the lichens Parmelia arseneana and Acarospora fuscata and in vitro antioxidant, antimicrobial, and anticancer activities of these extracts and gyrophoric acid isolated from A. fuscata. The HPLC-UV method was used for the identification of secondary metabolites. Stictic acid, norstictic acid, gyrophoric acid, usnic acid, atranorin and chloroatranorin were identified in the A. fuscata. In P. arseneana, we detected stictic acid, norstictic acid, usnic acid and atranorin, while gyrophoric acid was not identified. Antioxidant activity was evaluated by measuring the scavenging capacity of tested samples on DPPH and superoxide anion radicals, reducing the power of samples and determination of total phenolic compounds in extracts. As a result of the study, gyrophoric acid was found to have the largest DPPH radical scavenging activity with an IC50 value of 105.75 µg/ml. Moreover, the tested samples had an effective superoxide anion radical scavenging and reducing power. The total content of phenol in extracts was determined as pyrocatechol equivalent. The antimicrobial activity was estimated by determination of the minimal inhibitory concentration by the broth microdilution method. The most active was also gyrophoric acid, with minimum inhibitory concentration values ranging from 0.019 to 1.25 mg/ml. Anticancer activity was tested against LS174 (human colon carcinoma cell line), A549 (human lung carcinoma cell line), Fem-x (malignant melanoma cell line), and a chronic myelogeneous leukaemia K562 cell line using the MTT method. Extract of P. arseneana expressed the strongest anticancer activity against all cell lines with IC50 values ranging from 11.61 to 47.06 µg/ml. PMID:26417336

  3. Biological activities and chemical composition of lichens from Serbia.

    PubMed

    Kosanic, Marijana; Rankovic, Branislav; Stanojkovic, Tatjana; Vasiljevic, Perica; Manojlovic, Nedeljko

    2014-01-01

    The aim of this study is to investigate chemical composition of acetone extracts of the lichens Parmelia arseneana and Acarospora fuscata and in vitro antioxidant, antimicrobial, and anticancer activities of these extracts and gyrophoric acid isolated from A. fuscata. The HPLC-UV method was used for the identification of secondary metabolites. Stictic acid, norstictic acid, gyrophoric acid, usnic acid, atranorin and chloroatranorin were identified in the A. fuscata. In P. arseneana, we detected stictic acid, norstictic acid, usnic acid and atranorin, while gyrophoric acid was not identified. Antioxidant activity was evaluated by measuring the scavenging capacity of tested samples on DPPH and superoxide anion radicals, reducing the power of samples and determination of total phenolic compounds in extracts. As a result of the study, gyrophoric acid was found to have the largest DPPH radical scavenging activity with an IC50 value of 105.75 µg/ml. Moreover, the tested samples had an effective superoxide anion radical scavenging and reducing power. The total content of phenol in extracts was determined as pyrocatechol equivalent. The antimicrobial activity was estimated by determination of the minimal inhibitory concentration by the broth microdilution method. The most active was also gyrophoric acid, with minimum inhibitory concentration values ranging from 0.019 to 1.25 mg/ml. Anticancer activity was tested against LS174 (human colon carcinoma cell line), A549 (human lung carcinoma cell line), Fem-x (malignant melanoma cell line), and a chronic myelogeneous leukaemia K562 cell line using the MTT method. Extract of P. arseneana expressed the strongest anticancer activity against all cell lines with IC50 values ranging from 11.61 to 47.06 µg/ml. PMID:26417336

  4. Influences of chemical activators on incinerator bottom ash

    SciTech Connect

    Qiao, X.C. Cheeseman, C.R.; Poon, C.S.

    2009-02-15

    This research has applied different chemical activators to mechanically and thermally treated fine fraction (<14 mm) of incinerator bottom ash (IBA), in order to investigate the influences of chemical activators on this new pozzolanic material. IBA has been milled and thermally treated at 800 deg. C (TIBA). The TIBA produced was blended with Ca(OH){sub 2} and evaluated for setting time, reactivity and compressive strength after the addition of 0.0565 mole of Na{sub 2}SO{sub 4}, K{sub 2}SO{sub 4}, Na{sub 2}CO{sub 3}, K{sub 2}CO{sub 3}, NaOH, KOH and CaCl{sub 2} into 100 g of binder (TIBA+Ca(OH){sub 2}). The microstructures of activated IBA and hydrated samples have been characterized by X-ray diffraction (XRD) and thermogravimetry (TG) analysis. Thermal treatment is found to produce gehlenite (Ca{sub 2}Al{sub 2}SiO{sub 7}), wollastonite (CaSiO{sub 3}) and mayenite (Ca{sub 12}Al{sub 14}O{sub 33}) phases. The thermally treated IBA samples are significantly more reactive than the milled IBA. The addition of Na{sub 2}CO{sub 3} can increase the compressive strength and calcium hydroxide consumption at 28-day curing ages. However, the addition of Na{sub 2}SO{sub 4}, K{sub 2}SO{sub 4}, K{sub 2}CO{sub 3}, NaOH and KOH reduces the strength and hydration reaction. Moreover, these chemicals produce more porous samples due to increased generation of hydrogen gas. The addition of CaCl{sub 2} has a negative effect on the hydration of TIBA samples. Calcium aluminium oxide carbonate sulphide hydrate (Ca{sub 4}Al{sub 2}O{sub 6}(CO{sub 3}){sub 0.67}(SO{sub 3}){sub 0.33}(H{sub 2}O){sub 11}) is the main hydration product in the samples with activated IBA, except for the sample containing CaCl{sub 2}.

  5. Evaluation of antiseptic antiviral activity of chemical agents.

    PubMed

    Geller, Chloé; Finance, Chantal; Duval, Raphaël Emmanuel

    2011-06-01

    Antiviral antisepsis and disinfection are crucial for preventing the environmental spread of viral infections. Emerging viruses and associated diseases, as well as nosocomial viral infections, have become a real issue in medical fields, and there are very few efficient and specific treatments available to fight most of these infections. Another issue is the potential environmental resistance and spread of viral particles. Therefore, it is essential to properly evaluate the efficacy of antiseptics-disinfectants (ATS-D) on viruses. ATS-D antiviral activity is evaluated by (1) combining viruses and test product for an appropriately defined and precise contact time, (2) neutralizing product activity, and (3) estimating the loss of viral infectivity. A germicide can be considered to have an efficient ATS-D antiviral activity if it induces a >3 or >4 log(10) reduction (American and European regulatory agency requirements, respectively) in viral titers in a defined contact time. This unit describes a global methodology for evaluating chemical ATS-D antiviral activity.

  6. Speciation and chemical activities in superheated sodium borate solutions

    SciTech Connect

    Weres, O. )

    1993-06-01

    The system H[sub 2]O-B[sub 2]O[sub 3]-Na[sub 2]O has been studied experimentally at 277[degrees] and 317[degrees]C. The activities of water and boric acid have been determined at mole ratios Na/B from 0 to 1.5, and total dissolved solids 3 to 80 weight percent. The activity of boric acid has been fitted to within experimental error using a speciation model with eight complex species. This model is consistent with the model previously published by Mesmer et al. The electrolyte properties of the liquid are modelled using the Pitzer-Simonson Model of very concentrated electrolyte solutions. The calculated values of water activity agree with experiment, and the activity of NaOH and pOH have also been calculated. These data will allow prediction of the composition and chemical behavior of sodium borate liquids that may accumulate in the superheated crevices within a steam generator. A modified form of the model is provided for use with MULTEQ. The potassium borate system also was briefly studied at 317[degrees]C, and is adequately described by a model with five complex species. The potassium borate liquid is more alkaline at K/B = 1 than a sodium borate liquid at the same mole ratio, but pOH in the two systems is the same at lower mole ratios.

  7. Bulgy tadpoles: inducible defense morph.

    PubMed

    Kishida, Osamu; Nishimura, Kinya

    2004-08-01

    Predator induced morphological defenses are marked morphological shifts induced directly by cues associated with a predator. Generally, remote cues, i.e., chemical substances emitted from predators or injured conspecifics, are considered to be ideal signals to induce morphological change in aquatic environments rather than close cues, i.e., close chemical or tactile cues, since chemical substances that can propagate over relatively long distances and persist for a long period may allow organisms to keep safe and to deliberately change their morph. In fact, most organisms adopting an inducible morphological defense utilize remote chemical cues to detect predation risk and to produce morphological defenses. In this paper, we report a unique and functionally well designed inducible morphological defense strategy where the induction process requires close cues from a predator. The tadpoles of Rana pirica exhibited a bulgy bodied morphology when threatened with predation by larval salamanders, Hynobius retardatus, in close proximity. Predation trials and a function experiment showed that the induced bulgy morph is an adaptive defense phenotype against the gape-limited predator larval H. retardatus. Furthermore, R. pirica tadpoles use two adaptive strategies in terms of cost saving, i.e., adjustment of the extent of bulginess according to predation risk and reversibility by actual shrink of bulgy body after removing the predation threat. In general, R. pirica hatch earlier than H. retardatus. In natural ponds, during the early developmental stage R. pirica tadpoles live in close proximity to young H. retardatus larvae. As they grow, the salamanders gradually become serious predators and the predator-prey interaction becomes intimate. After a while, predation, cannibalism and metamorphosis decrease the number of salamanders in the ponds, and the predator-prey interaction weakens. Such a phenology in the predator-prey interaction allows the evolution of a close

  8. Bulgy tadpoles: inducible defense morph.

    PubMed

    Kishida, Osamu; Nishimura, Kinya

    2004-08-01

    Predator induced morphological defenses are marked morphological shifts induced directly by cues associated with a predator. Generally, remote cues, i.e., chemical substances emitted from predators or injured conspecifics, are considered to be ideal signals to induce morphological change in aquatic environments rather than close cues, i.e., close chemical or tactile cues, since chemical substances that can propagate over relatively long distances and persist for a long period may allow organisms to keep safe and to deliberately change their morph. In fact, most organisms adopting an inducible morphological defense utilize remote chemical cues to detect predation risk and to produce morphological defenses. In this paper, we report a unique and functionally well designed inducible morphological defense strategy where the induction process requires close cues from a predator. The tadpoles of Rana pirica exhibited a bulgy bodied morphology when threatened with predation by larval salamanders, Hynobius retardatus, in close proximity. Predation trials and a function experiment showed that the induced bulgy morph is an adaptive defense phenotype against the gape-limited predator larval H. retardatus. Furthermore, R. pirica tadpoles use two adaptive strategies in terms of cost saving, i.e., adjustment of the extent of bulginess according to predation risk and reversibility by actual shrink of bulgy body after removing the predation threat. In general, R. pirica hatch earlier than H. retardatus. In natural ponds, during the early developmental stage R. pirica tadpoles live in close proximity to young H. retardatus larvae. As they grow, the salamanders gradually become serious predators and the predator-prey interaction becomes intimate. After a while, predation, cannibalism and metamorphosis decrease the number of salamanders in the ponds, and the predator-prey interaction weakens. Such a phenology in the predator-prey interaction allows the evolution of a close

  9. 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

  10. Synthetic plant defense elicitors

    PubMed Central

    Bektas, Yasemin; Eulgem, Thomas

    2015-01-01

    To defend themselves against invading pathogens plants utilize a complex regulatory network that coordinates extensive transcriptional and metabolic reprogramming. Although many of the key players of this immunity-associated network are known, the details of its topology and dynamics are still poorly understood. As an alternative to forward and reverse genetic studies, chemical genetics-related approaches based on bioactive small molecules have gained substantial popularity in the analysis of biological pathways and networks. Use of such molecular probes can allow researchers to access biological space that was previously inaccessible to genetic analyses due to gene redundancy or lethality of mutations. Synthetic elicitors are small drug-like molecules that induce plant defense responses, but are distinct from known natural elicitors of plant immunity. While the discovery of some synthetic elicitors had already been reported in the 1970s, recent breakthroughs in combinatorial chemical synthesis now allow for inexpensive high-throughput screens for bioactive plant defense-inducing compounds. Along with powerful reverse genetics tools and resources available for model plants and crop systems, comprehensive collections of new synthetic elicitors will likely allow plant scientists to study the intricacies of plant defense signaling pathways and networks in an unparalleled fashion. As synthetic elicitors can protect crops from diseases, without the need to be directly toxic for pathogenic organisms, they may also serve as promising alternatives to conventional biocidal pesticides, which often are harmful for the environment, farmers and consumers. Here we are discussing various types of synthetic elicitors that have been used for studies on the plant immune system, their modes-of-action as well as their application in crop protection. PMID:25674095

  11. High humidity suppresses ssi4-mediated cell death and disease resistance upstream of MAP kinase activation, H2O2 production and defense gene expression.

    PubMed

    Zhou, Fasong; Menke, Frank L H; Yoshioka, Keiko; Moder, Wolfgang; Shirano, Yumiko; Klessig, Daniel F

    2004-09-01

    The Arabidopsis ssi4 mutant, which exhibits spontaneous lesion formation, constitutive expression of pathogenesis-related (PR) genes and enhanced resistance to virulent bacterial and oomycete pathogens, contains a gain-of-function mutation in a TIR-NBS-LRR type R gene. Epistatic analyses revealed that both PR gene expression and disease resistance are activated via a salicylic acid (SA)- and EDS1-dependent, but NPR1- and NDR1-independent signaling pathway. In this study, we demonstrate that in moderate relative humidity (RH; 60%), the ssi4 mutant accumulates H(2)O(2) and SA prior to lesion formation and displays constitutive activation of the MAP kinases AtMPK6 and AtMPK3. It also constitutively expresses a variety of defense-associated genes, including those encoding the WRKY transcription factors AtWRKY29 and AtWRKY6, the MAP kinases AtMPK6 and AtMPK3, the powdery mildew R proteins RPW8.1 and RPW8.2, EDS1 and PR proteins. All of these ssi4-induced responses, as well as the chlorotic, stunted morphology and enhanced disease resistance phenotype, are suppressed by high RH (95%) growth conditions. Thus, a humidity sensitive factor (HSF) appears to function at an early point in the ssi4 signaling pathway. All ssi4 phenotypes, except for MAP kinase activation, also were suppressed by the eds1-1 mutation. Thus, ssi4-induced MAP kinase activation occurs downstream of the HSF but either upstream of EDS1 or on a separate branch of the ssi4 signaling pathway. SA is a critical signaling component in ssi4-mediated defense responses. However, exogenously supplied SA failed to restore lesion formation in high RH-grown ssi4 plants, although it induced defense gene expression. Thus, additional signals also are involved.

  12. Advances in mechanisms of activation and deactivation of environmental chemicals.

    PubMed Central

    Goldstein, J A; Faletto, M B

    1993-01-01

    Environmental chemicals are both activated and detoxified by phase I and phase II enzymes. The principal enzymes involved in phase I reactions are the cytochrome P-450s. The phase II enzymes include hydrolase and the conjugative enzymes such as glucuronyltransferases, glutathione transferases, N-acetyltransferase, and sulfotransferase. Although other phase I and phase II enzymes exist, the present review is limited to these enzymes. Once thought to be a single enzyme, multiple cytochrome P-450 enzymes have been purified and characterized from many different species across the evolutionary tree. The application of molecular biology techniques to this field has identified more than 150 cytochrome P-450 genes to date. At least 20-30 cytochrome P-450 enzymes appear to exist in each mammalian species, and many polymorphisms in these enzymes are being identified. The cytochrome P-450 enzymes can now be expressed in recombinant form using cDNA expression systems. The phase II conjugative enzymes add a hydrophilic moiety such as sulfate, glucuronide, or acetate to compounds, which increases their water solubility and facilitates their excretion. However, conjugates of a number of compounds also result in more reactive electrophilic species, which appear to be the ultimate carcinogens. Many of these phase II enzymes also represent families of enzymes, and polymorphisms can affect the ability of these enzymes to metabolize chemicals. Whenever possible, we have reviewed knowledge of the human enzymes involved in particular pathways. PMID:8354165

  13. Defense use and defense understanding in children.

    PubMed

    Cramer, P; Brilliant, M A

    2001-04-01

    This study investigated the relation between children's use of defense mechanisms and their understanding of those defenses. We hypothesized that, once a child understands how a particular defense functions, the use of that defense will no longer be successful and will be replaced by another defense mechanism that is not yet understood. Defense use was assessed from the Thematic Appreception Test (TAT) stories told by 122 children; defense understanding was determined from the children's understanding of stories portraying defenses. The results indicated that younger children (mean age = 7-8) used the defense of denial more than the older children (mean age = 9-11). Older children understood the functioning of denial and projection better than the younger children. A comparison of children who did and did not understand a defense showed that younger children who understood the functioning of denial were less likely to themselves use denial. Likewise, older children who understood the functioning of projection were less likely to use this defense.

  14. [Chemical constituents from Callicarpa nudiflora and their cytotoxic activities].

    PubMed

    Ma, Yan-Chun; Zhang, Min; Xu, Wen-Tong; Feng, Shi-Xiu; Lei, Ming; Yi, Bo

    2014-08-01

    The chemical consitituents from cytotoxic fraction of the Callicarpa nudiflora extract were isolated and purified by a combination of HP-20 macroporous resin, silica gel and Sephadex LH-20 column chromatographies. The structures were elucidated on the basis of the spectroscopic data and comparison of their spectroscopic data with reported data. The cytotoxicity was evaluated by the MTT assay. The 50% and 70% EtOH elutions of EtOH-extract showed significant cytotoxic activities, leading to the isolation of twelve compounds, which were identified as luteoloside(1), lutedin-4'-O-β-D-glucoside(2), 6-hydroxyluteolin-7-O-β-glucoside(3), lutedin-7-O-neohesperidoside(4), rhoifolin (5), luteolin-7, 4'-di-O-glucoside (6), forsythoside B (7), acteoside (8), alyssonoside (9), catalpol(10), nudifloside(11), and leonuride(12). Compounds 3-6, 10 and 12 were isolated from this genus for the first time, and compound 9 was isolated from this plant for the first time. The cytotoxicity assay demonstrated that flavonoids 1-6, in various concentrations, showed monolithic proliferation inhibitory activities against Hela, A549 and MCF-7 cell lines. Compounds 3, 5 and iridoid glycoside 11 possessed higher cytotoxicacivities. In short, flavonoids are the main components of cytotoxic extract from C. nudiflora, while phenylethanoid glycosides are the predominant ingredient but inactive to cancer cell lines. In addition, the minor iridoid glycoside expressed weak cytotoxic activity.

  15. Flaxseed hull: Chemical composition and antioxidant activity during development.

    PubMed

    Herchi, Wahid; Al Hujaili, Abdullah D; Sakouhi, Faouzi; Sebei, Khaled; Trabelsi, Hajer; Kallel, Habib; Boukhchina, Sadok

    2014-01-01

    Changes in the chemical composition and antioxidant activity of flaxseed hull during maturation were investigated. P129 hull variety was studied at four maturation stages (St1, St2, St3, and St4). Significant variation in proximate composition and flaxseed hull oil characteristics were observed. A significant increase in the carbohydrates content of the hull was observed during development. The main methyl esters were linolenic acid (48.95 - 51.52 %), oleic acid (20.27-23.41%) and linoleic acid (15.62-17.70%). The highest polyunsaturated fatty acids (PUFA) were found to be 67.14 % at the first stage of maturity (St1). Flaxseed hull oil was of good quality, containing an abundance of omega-3 essential fatty acids. The iodine value increased, while the saponification value of oil decreased during seed development. The decrease in ascorbic acid content was steady. The maximum level of total phenolic acid content (128.3 mg/100 g oil) was reached at 7 DAF. The antioxidant activity of oilseed was assessed by means of 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging assay. Radical scavenging activity for green hull was 52.74% and mature hull was 69.32%. PMID:24919478

  16. Advances in the chemical analysis and biological activities of chuanxiong.

    PubMed

    Li, Weixia; Tang, Yuping; Chen, Yanyan; Duan, Jin-Ao

    2012-01-01

    Chuanxiong Rhizoma (Chuan-Xiong, CX), the dried rhizome of Ligusticum chuanxiong Hort. (Umbelliferae), is one of the most popular plant medicines in the World. Modern research indicates that organic acids, phthalides, alkaloids, polysaccharides, ceramides and cerebrosides are main components responsible for the bioactivities and properties of CX. Because of its complex constituents, multidisciplinary techniques are needed to validate the analytical methods that support CX's use worldwide. In the past two decades, rapid development of technology has advanced many aspects of CX research. The aim of this review is to illustrate the recent advances in the chemical analysis and biological activities of CX, and to highlight new applications and challenges. Emphasis is placed on recent trends and emerging techniques. PMID:22955453

  17. Chemical constituents and biological activities of the genus Linaria (Scrophulariaceae).

    PubMed

    Cheriet, Thamere; Mancini, Ines; Seghiri, Ramdane; Benayache, Fadila; Benayache, Samir

    2015-01-01

    This is a review on 95 references dealing with the genus Linaria (Scrophularioideae-Antirrhineae tribe), a known genus of the Scrophulariaceae family, which comprises about 200 species mainly distributed in Europe, Asia and North Africa. The use of some Linaria species in folk medicine has attracted the attention for chemical and biological studies. This report is aimed to be a comprehensive overview on the isolated or identified known and often new metabolites from the 41 Linaria species so far cited. It is organised presenting first the phytochemical classes of alkaloids, polyphenols including flavonoids, the latter being quite diffused and mostly present as flavones, flavonols and their glycosides, and terpenoids including iridoids and steroids. Second, the results from biological investigation on plant extracts, pure natural products isolated from Linaria species and some synthetic derivatives are reported, with antitumour, anti-acetylcholinesterase, anti-inflammatory and analgesic, antioxidant and antibacterial activities. PMID:25674928

  18. Thymus vulgaris essential oil: chemical composition and antimicrobial activity.

    PubMed

    Borugă, O; Jianu, C; Mişcă, C; Goleţ, I; Gruia, A T; Horhat, F G

    2014-01-01

    The study was designed to determine the chemical composition and antimicrobial properties of the essential oil of Thymus vulgaris cultivated in Romania. The essential oil was isolated in a yield of 1.25% by steam distillation from the aerial part of the plant and subsequently analyzed by GC-MS. The major components were p-cymene (8.41%), γ-terpinene (30.90%) and thymol (47.59%). Its antimicrobial activity was evaluated on 7 common food-related bacteria and fungus by using the disk diffusion method. The results demonstrate that the Thymus vulgaris essential oil tested possesses strong antimicrobial properties, and may in the future represent a new source of natural antiseptics with applications in the pharmaceutical and food industry. PMID:25870697

  19. Activity based chemical proteomics: profiling proteases as drug targets.

    PubMed

    Heal, William Percy; Wickramasinghe, Sasala Roshinie; Tate, Edward William

    2008-09-01

    The pivotal role of proteases in many diseases has generated considerable interest in their basic biology, and in the potential to target them for chemotherapy. Although fundamental to the initiation and progression of diseases such as cancer, diabetes, arthritis and malaria, in many cases their precise role remains unknown. Activity-based chemical proteomics-an emerging field involving a combination of organic synthesis, biochemistry, cell biology, biophysics and bioinformatics-allows the detection, visualisation and activity quantification of whole families or selected sub-sets of proteases based upon their substrate specificity. This approach can be applied for drug target/lead identification and validation, the fundamentals of drug discovery. The activity-based probes discussed in this review contain three key features; a 'warhead' (binds irreversibly but selectively to the active site), a 'tag' (allowing enzyme 'handling', with a combination of fluorescent, affinity and/or radio labels), and a linker region between warhead and tag. From the design and synthesis of the linker arise some of the latest developments discussed here; not only can the physical properties (e.g., solubility, localisation) of the probe be tuned, but the inclusion of a cleavable moiety allows selective removal of tagged enzyme from affinity beads etc. The design and synthesis of recently reported probes is discussed, including modular assembly of highly versatile probes via solid phase synthesis. Recent applications of activity-based protein profiling to specific proteases (serine, threonine, cysteine and metalloproteases) are reviewed as are demonstrations of their use in the study of disease function in cancer and malaria.

  20. 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.

  1. 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

  2. Effects of exposure to sublethal propiconazole on the antioxidant defense system and Na+-K+-ATPase activity in brain of rainbow trout, Oncorhynchus mykiss.

    PubMed

    Li, Zhi-Hua; Zlabek, Vladimir; Grabic, Roman; Li, Ping; Machova, Jana; Velisek, Josef; Randak, Tomas

    2010-07-01

    Propiconazole (PCZ), a triazole fungicide, is widely present in the aquatic environment, but little is known regarding its chronic toxicity in the fish brain. This study assessed the effects of long-term exposure to PCZ on the antioxidant defense system and Na(+)-K(+)-ATPase activity of rainbow trout brain. Fish were exposed to sublethal concentrations of PCZ (0.2, 50, and 500 microg/l) for 7, 20, and 30 days, respectively. Oxidative stress indices (reactive oxygen species, lipid peroxidation, and carbonyl protein) and antioxidant parameters (superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, and reduced glutathione) were measured, as well as Na(+)-K(+)-ATPase activity. Adaptive responses to PCZ-induced stress were observed at 7 days. With prolonged exposure, significantly higher levels of oxidative indices were indicative of oxidative stress, as also were the significant inhibition of antioxidant enzyme activity and reduced glutathione content. Na(+)-K(+)-ATPase activity was significantly inhibited after prolonged exposure. Chemometrics of all parameters by principal component analysis, enabled the separation of sampled individuals into four groups with 93.39% of total accumulated variance. A low level of oxidative stress can induce the adaptive responses of the antioxidant defense system, while prolonged exposure to PCZ may lead to serious oxidative damage in fish brain. We suggest that selected biochemical markers in fish brain could be used as potential biomarkers for monitoring residual fungicides present in the aquatic environments.

  3. Chemical Tools of Octopus maya during Crab Predation Are Also Active on Conspecifics.

    PubMed

    Pech-Puch, Dawrin; Cruz-López, Honorio; Canche-Ek, Cindy; Campos-Espinosa, Gabriela; García, Elpidio; Mascaro, Maite; Rosas, Carlos; Chávez-Velasco, Daniel; Rodríguez-Morales, Sergio

    2016-01-01

    Octopus maya is a major socio-economic resource from the Yucatán Peninsula in Mexico. In this study we report for the first time the chemical composition of the saliva of O. maya and its effect on natural prey, i.e. the blue crab (Callinectes sapidus), the crown conch snail (Melongena corona bispinosa), as well as conspecifics. Salivary posterior glands were collected from octopus caught by local fishers and extracted with water; this extract paralyzed and predigested crabs when it was injected into the third pereiopod. The water extract was fractionated by membrane ultrafiltration with a molecular weight cut-off of 3 kDa leading to a metabolic phase (>3 kDa) and a neurotoxic fraction (<3 kDa). The neurotoxic fraction injected in the crabs caused paralysis and postural changes. Crabs recovered to their initial condition within two hours, which suggests that the effects of the neurotoxic fraction were reversible. The neurotoxic fraction was also active on O. maya conspecifics, partly paralyzing and sedating them; this suggests that octopus saliva might be used among conspecifics for defense and for reduction of competition. Bioguided separation of the neurotoxic fraction by chromatography led to a paralysis fraction and a relaxing fraction. The paralyzing activity of the saliva was exerted by amino acids, while the relaxing activity was due to the presence of serotonin. Prey-handling studies revealed that O. maya punctures the eye or arthrodial membrane when predating blue crabs and uses the radula to bore through crown conch shells; these differing strategies may help O. maya to reduce the time needed to handle its prey.

  4. Chemical Tools of Octopus maya during Crab Predation Are Also Active on Conspecifics

    PubMed Central

    Pech-Puch, Dawrin; Cruz-López, Honorio; Canche-Ek, Cindy; Campos-Espinosa, Gabriela; García, Elpidio; Mascaro, Maite; Rosas, Carlos; Chávez-Velasco, Daniel; Rodríguez-Morales, Sergio

    2016-01-01

    Octopus maya is a major socio-economic resource from the Yucatán Peninsula in Mexico. In this study we report for the first time the chemical composition of the saliva of O. maya and its effect on natural prey, i.e. the blue crab (Callinectes sapidus), the crown conch snail (Melongena corona bispinosa), as well as conspecifics. Salivary posterior glands were collected from octopus caught by local fishers and extracted with water; this extract paralyzed and predigested crabs when it was injected into the third pereiopod. The water extract was fractionated by membrane ultrafiltration with a molecular weight cut-off of 3kDa leading to a metabolic phase (>3kDa) and a neurotoxic fraction (<3kDa). The neurotoxic fraction injected in the crabs caused paralysis and postural changes. Crabs recovered to their initial condition within two hours, which suggests that the effects of the neurotoxic fraction were reversible. The neurotoxic fraction was also active on O. maya conspecifics, partly paralyzing and sedating them; this suggests that octopus saliva might be used among conspecifics for defense and for reduction of competition. Bioguided separation of the neurotoxic fraction by chromatography led to a paralysis fraction and a relaxing fraction. The paralyzing activity of the saliva was exerted by amino acids, while the relaxing activity was due to the presence of serotonin. Prey-handling studies revealed that O. maya punctures the eye or arthrodial membrane when predating blue crabs and uses the radula to bore through crown conch shells; these differing strategies may help O. maya to reduce the time needed to handle its prey. PMID:26895025

  5. Chemical Tools of Octopus maya during Crab Predation Are Also Active on Conspecifics.

    PubMed

    Pech-Puch, Dawrin; Cruz-López, Honorio; Canche-Ek, Cindy; Campos-Espinosa, Gabriela; García, Elpidio; Mascaro, Maite; Rosas, Carlos; Chávez-Velasco, Daniel; Rodríguez-Morales, Sergio

    2016-01-01

    Octopus maya is a major socio-economic resource from the Yucatán Peninsula in Mexico. In this study we report for the first time the chemical composition of the saliva of O. maya and its effect on natural prey, i.e. the blue crab (Callinectes sapidus), the crown conch snail (Melongena corona bispinosa), as well as conspecifics. Salivary posterior glands were collected from octopus caught by local fishers and extracted with water; this extract paralyzed and predigested crabs when it was injected into the third pereiopod. The water extract was fractionated by membrane ultrafiltration with a molecular weight cut-off of 3 kDa leading to a metabolic phase (>3 kDa) and a neurotoxic fraction (<3 kDa). The neurotoxic fraction injected in the crabs caused paralysis and postural changes. Crabs recovered to their initial condition within two hours, which suggests that the effects of the neurotoxic fraction were reversible. The neurotoxic fraction was also active on O. maya conspecifics, partly paralyzing and sedating them; this suggests that octopus saliva might be used among conspecifics for defense and for reduction of competition. Bioguided separation of the neurotoxic fraction by chromatography led to a paralysis fraction and a relaxing fraction. The paralyzing activity of the saliva was exerted by amino acids, while the relaxing activity was due to the presence of serotonin. Prey-handling studies revealed that O. maya punctures the eye or arthrodial membrane when predating blue crabs and uses the radula to bore through crown conch shells; these differing strategies may help O. maya to reduce the time needed to handle its prey. PMID:26895025

  6. Cytotoxic activity and chemical constituents of Anthemis mirheydari.

    PubMed

    Jassbi, Amir Reza; Firuzi, Omidreza; Miri, Ramin; Salhei, Sajad; Zare, Somayeh; Zare, Mehdi; Masroorbabanari, Mehdi; Chandran, Jima N; Schneider, Bernd; Baldwin, Ian T

    2016-10-01

    Context The genus Anthemis L. (Asteraceae) comprises about 195 species which are widely used in the pharmaceutical, cosmetic and food industries. Objective Anthemis mirheydari Iranshar, an endemic plant from Iran, was investigated for its cytotoxic properties and chemical constituents. Materials and methods The whole parts of the plant (320 g) were extracted by dichloromethane and methanol for four days, successively. The cytotoxic activity of both dichloromethane and methanol extracts were assayed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide colorimetric methods against three human cancer cell lines including LS180, MCF-7 and MOLT-4. Different concentrations (10-100 μg/mL) of the plant extracts were tested to obtain IC50 values. The dichloromethane extract of A. mirheydari was subjected to silica gel-column and thin layer chromatography for purification of its chemical constituents and the isolated compounds were further tested against MOLT-4 cells. The structures of the pure compounds were elucidated using different spectral data including nuclear magnetic resonance and electron impact mass spectra. Results The IC50 values of the dichloromethane extract were 30.8 ± 6.7, 25.2 ± 6.5 and 8.6 ± 1.1 μg/mL (means ± standard error) for the above-mentioned cell lines, respectively. Two triterpenoids, taraxasterol (1) and pseudotaraxasterol (2), one sterol, β-sitosterol (3) and one coumarin, 7-methoxycoumarin (4) were isolated from the extract. The IC50 of the mixture of compounds 1 and 2 as well as compounds 3 and 4 were higher (>100 μM) than that reported for the dichloromethane extract against MOLT-4 cells. Conclusion The dichloromethane extract was the most active one among the tested material.

  7. Dynamic model for selective metabolic activation in chemical carcinogenesis

    SciTech Connect

    Selkirk, J.K.; MacLeod, M.C.

    1980-01-01

    Theoretical calculations predict the relative ease of formation of carbonium ions from 7,8-dihydro-7,8-dihydroxybenzo(a)pyrene-9,10-oxide or from either of the 2 symmetrical bay regions of B(e)P, and suggest their attraction to cellular nucleophiles. When both isomers were metabolized by hamster embryo fibroblasts (HEF) and the products analyzed, the results showed that the probable reason for benzo(e)pyrene's lack of carcinogenicity was its metabolic preference to attack the molecule away from the bay-region area. Particularly striking was the absence of any evidence for the formation of a significant amount of B(e)P-9,10-dihydrodiol. This suggests a metabolic basis for the relative lack of carcinogenic and mutagenic activity of B(e)P. The reason for this is not clear but may be due to physical or chemical factors such as membrane solubility or stereochemical requirements of the active site of the enzyme. The bay-region theory of PAH carcinogenesis predicts that carbonium ion formation from 9,10-dihydro-9,10-dihydroxybenzo(e)pyrene-11, 12-oxide, if formed, would be energetically favorable. Thus, the inability of HEF and microcomes to form B(e)P-9,10-dihydrodiol, the precursor of its potentially highly reactive diol-epoxide, would explain the relative inertness of B(e)P in several biological systems. As the subtle biochemical interactions of the various carcinogen intermediates become clarified, it becomes apparent that susceptibility and resistance to malignant transformation are based on a complex set of both chemical and physical parameters. It is becoming clear that metabolism kinetics, membrane interaction, and the role of nuclear metabolism help dictate the passage of the carcinogen and its reactive intermediates into and through the metabolic machinery of the cell. (ERB)

  8. Active sampling technique to enhance chemical signature of buried explosives

    NASA Astrophysics Data System (ADS)

    Lovell, John S.; French, Patrick D.

    2004-09-01

    Deminers and dismounted countermine engineers commonly use metal detectors, ground penetrating radar and probes to locate mines. Many modern landmines have a very low metal content, which severely limits the effectiveness of metal detectors. Canines have also been used for landmine detection for decades. Experiments have shown that canines smell the explosives which are known to leak from most types of landmines. The fact that dogs can detect landmines indicates that vapor sensing is a viable approach to landmine detection. Several groups are currently developing systems to detect landmines by "sniffing" for the ultra-trace explosive vapors above the soil. The amount of material that is available to passive vapor sensing systems is limited to no more than the vapor in equilibrium with the explosive related chemicals (ERCs) distributed in the surface soils over and near the landmine. The low equilibrium vapor pressure of TNT in the soil/atmosphere boundary layer and the limited volume of the boundary layer air imply that passive chemical vapor sensing systems require sensitivities in the picogram range, or lower. ADA is working to overcome many of the limitations of passive sampling methods, by the use of an active sampling method that employs a high-powered (1,200+ joules) strobe lamp to create a highly amplified plume of vapor and/or ERC-bearing fine particulates. Initial investigations have demonstrated that this approach can amplify the detectability of TNT by two or three orders of magnitude. This new active sampling technique could be used with any suitable explosive sensor.

  9. INCREASED ENDOCRINE ACTIVITY OF XENOBIOTIC CHEMICALS AS MEDIATED BY METABOLIC ACTIVATION

    EPA Science Inventory

    This research is part of an effort to develop in vitro assays and QSARs applicable to untested chemicals on EPA inventories through study of estrogen receptor (ER) binding and estrogen mediated gene expression in fish. The current effort investigates metabolic activation of chemi...

  10. Defensive weapons and defense signals in plants: some metabolites serve both roles.

    PubMed

    Maag, Daniel; Erb, Matthias; Köllner, Tobias G; Gershenzon, Jonathan

    2015-02-01

    The defense of plants against herbivores and pathogens involves the participation of an enormous range of different metabolites, some of which act directly as defensive weapons against enemies (toxins or deterrents) and some of which act as components of the complex internal signaling network that insures that defense is timed to enemy attack. Recent work reveals a surprising trend: The same compounds may act as both weapons and signals of defense. For example, two groups of well-studied defensive weapons, glucosinolates and benzoxazinoids, trigger the accumulation of the protective polysaccharide callose as a barrier against aphids and pathogens. In the other direction, several hormones acting in defense signaling (and their precursors and products) exhibit activity as weapons against pathogens. Knowing which compounds are defensive weapons, which are defensive signals and which are both is vital for understanding the functioning of plant defense systems.

  11. Interferon-γ Is a Crucial Activator of Early Host Immune Defense against Mycobacterium ulcerans Infection in Mice

    PubMed Central

    Bieri, Raphael; Bolz, Miriam; Ruf, Marie-Thérèse; Pluschke, Gerd

    2016-01-01

    Buruli ulcer (BU), caused by infection with Mycobacterium ulcerans, is a chronic necrotizing human skin disease associated with the production of the cytotoxic macrolide exotoxin mycolactone. Despite extensive research, the type of immune responses elicited against this pathogen and the effector functions conferring protection against BU are not yet fully understood. While histopathological analyses of advanced BU lesions have demonstrated a mainly extracellular localization of the toxin producing acid fast bacilli, there is growing evidence for an early intra-macrophage growth phase of M. ulcerans. This has led us to investigate whether interferon-γ might play an important role in containing M. ulcerans infections. In an experimental Buruli ulcer mouse model we found that interferon-γ is indeed a critical regulator of early host immune defense against M. ulcerans infections. Interferon-γ knockout mice displayed a faster progression of the infection compared to wild-type mice. This accelerated progression was reflected in faster and more extensive tissue necrosis and oedema formation, as well as in a significantly higher bacterial burden after five weeks of infection, indicating that mice lacking interferon-γ have a reduced capacity to kill intracellular bacilli during the early intra-macrophage growth phase of M. ulcerans. This data demonstrates a prominent role of interferon-γ in early defense against M. ulcerans infection and supports the view that concepts for vaccine development against tuberculosis may also be valid for BU. PMID:26863011

  12. Interferon-γ Is a Crucial Activator of Early Host Immune Defense against Mycobacterium ulcerans Infection in Mice.

    PubMed

    Bieri, Raphael; Bolz, Miriam; Ruf, Marie-Thérèse; Pluschke, Gerd

    2016-02-01

    Buruli ulcer (BU), caused by infection with Mycobacterium ulcerans, is a chronic necrotizing human skin disease associated with the production of the cytotoxic macrolide exotoxin mycolactone. Despite extensive research, the type of immune responses elicited against this pathogen and the effector functions conferring protection against BU are not yet fully understood. While histopathological analyses of advanced BU lesions have demonstrated a mainly extracellular localization of the toxin producing acid fast bacilli, there is growing evidence for an early intra-macrophage growth phase of M. ulcerans. This has led us to investigate whether interferon-γ might play an important role in containing M. ulcerans infections. In an experimental Buruli ulcer mouse model we found that interferon-γ is indeed a critical regulator of early host immune defense against M. ulcerans infections. Interferon-γ knockout mice displayed a faster progression of the infection compared to wild-type mice. This accelerated progression was reflected in faster and more extensive tissue necrosis and oedema formation, as well as in a significantly higher bacterial burden after five weeks of infection, indicating that mice lacking interferon-γ have a reduced capacity to kill intracellular bacilli during the early intra-macrophage growth phase of M. ulcerans. This data demonstrates a prominent role of interferon-γ in early defense against M. ulcerans infection and supports the view that concepts for vaccine development against tuberculosis may also be valid for BU.

  13. Relation between chemical composition or antioxidant activity and antihypertensive activity for six essential oils.

    PubMed

    Yvon, Yan; Raoelison, Emmanuel Guy; Razafindrazaka, René; Randriantsoa, Adolphe; Romdhane, Mehrez; Chabir, Naziha; Mkaddem, Mounira Guedri; Bouajila, Jalloul

    2012-08-01

    Six essential oils (EOs), Juniperus phoenicea (leaves and berries), Thymus capitatus, Lauris nobilis, Melaleuca armillaris, and Eucalyptus gracilis, were screened for their antioxidant and antihypertensive activity as well as their chemical compositions. We identified and quantified 24 compounds (representing 99.8% of total oil) for J. phoenicea leaves, 14 compounds (representing 98.8% of total oil) for J. phoenicea berries, 11 compounds (representing 99.6% of total oil) for T. capitatus, 32 compounds (representing 98.9% of total oil) for L. nobilis, 32 compounds (representing 98.7% of total oil) for M. armillaris, and 26 compounds (representing 99.3% of total oil) for E. gracilis. In the 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay, the antioxidant activity was in the range of 0.59 to 2183.6 mg/L, whereas T. capitatus (1.24 ± 0.05 mg/L) gave the best activity in the 2,2'-azinobis-3-ethylbenzothiazoline-6-sulfonate assay. Antihypertensive activity was evaluated by testing the vasorelaxing capacity of EOs on rat aorta precontracted by phenylephrine (10(-6) M). T. capitatus and L. nobilis were most active for an antihypertensive activity (29 ± 3 and 59 ± 2 mg/L, respectively). Correlations between chemical composition or antioxidant activity and/or antihypertensive activity were studied. Significant correlation has been found for antihypertensive activity and p-cymene (R(2) = 0.86), β-elemene (R(2) = 0.90), and β-myrcene (R(2) = 0.76). A good correlation has been found between antihypertensive activity and antioxidant activity by DPPH assay (R(2) = 0.98). Antioxidant activity can contribute to the prevention of the increase of the blood pressure. According to the literature, no study has been reported until now of correlation between antihypertensive activity and antioxidant activity. Natural EOs can find its interest and application in a medicinal area. PMID:22860587

  14. Chemical activation by mechanochemical mixing, microwave, and ultrasonic irradiation

    EPA Science Inventory

    The use of emerging MW-assisted chemistry techniques in conjunction with benign reaction media is dramatically reducing chemical waste ad reaction times in several organic syntheses and chemical transformations. This editorial comments on the recent developments in mechanochemica...

  15. Chemically modified RNA activated matrices enhance bone regeneration.

    PubMed

    Elangovan, Satheesh; Khorsand, Behnoush; Do, Anh-Vu; Hong, Liu; Dewerth, Alexander; Kormann, Michael; Ross, Ryan D; Sumner, D Rick; Allamargot, Chantal; Salem, Aliasger K

    2015-11-28

    There exists a dire need for improved therapeutics to achieve predictable bone regeneration. Gene therapy using non-viral vectors that are safe and efficient at transfecting target cells is a promising approach to overcoming the drawbacks of protein delivery of growth factors. Here, we investigated the transfection efficiency, cytotoxicity, osteogenic potential and in vivo bone regenerative capacity of chemically modified ribonucleic acid (cmRNA) (encoding BMP-2) complexed with polyethylenimine (PEI) and made comparisons with PEI complexed with conventional plasmid DNA (encoding BMP-2). The polyplexes were fabricated at an amine (N) to phosphate (P) ratio of 10 and characterized for transfection efficiency using human bone marrow stromal cells (BMSCs). The osteogenic potential of BMSCs treated with these polyplexes was validated by determining the expression of bone-specific genes, osteocalcin and alkaline phosphatase as well as through the detection of bone matrix deposition. Using a calvarial bone defect model in rats, it was shown that PEI-cmRNA (encoding BMP-2)-activated matrices promoted significantly enhanced bone regeneration compared to PEI-plasmid DNA (BMP-2)-activated matrices. Our proof of concept study suggests that scaffolds loaded with non-viral vectors harboring cmRNA encoding osteogenic proteins may be a powerful tool for stimulating bone regeneration with significant potential for clinical translation. PMID:26415855

  16. Chemical properties and antioxidant and antimicrobial activities of Slovenian propolis.

    PubMed

    Mavri, Ana; Abramovič, Helena; Polak, Tomaž; Bertoncelj, Jasna; Jamnik, Polona; Smole Možina, Sonja; Jeršek, Barbara

    2012-08-01

    The chemical composition as well as the antioxidant and antimicrobial activities of two EtOH extracts of propolis (PEEs) from Slovenia were determined. EtOH was used as extracting solvent at 70 and 96%, providing the extracts PEE70 and PEE96, respectively. The extraction with 70% EtOH was more efficient than that with 96% EtOH, as the PEE70 was richer in total phenolic compounds than the PEE96. The Slovenian propolis was characterized by different phenolic acids and flavonoids. The PEE96 was slightly richer in three specific compounds, i.e., caffeic acid, ferulic acid, and luteolin, while all other substances detected showed higher contents in the PEE70. The PEE70 showed a stronger reducing power and ability to scavenge free radicals and metal ions than the PEE96. Both PEEs were in the main more effective against Gram-positive bacteria than against fungi and Gram-negative bacteria like Salmonella and Escherichia coli, with the exception of Campylobacter. The PEE96 decreased the intracellular oxidation in Saccharomyces cerevisiae in a dose-dependent manner. The antimicrobial activities and antioxidant properties were related to the total phenolic contents. The two PEEs have the potential for use as natural antimicrobial and antioxidant additives in foods.

  17. THE USE OF STRUCTURE-ACTIVITY RELATIONSHIPS IN INTEGRATING THE CHEMISTRY AND TOXICOLOGY OF ENDOCRINE DISRUPTING CHEMICALS

    EPA Science Inventory

    Structure activity relationships (SARs) are based on the principle that structurally similar chemicals should have similar biological activity. SARs relate specifically-defined toxicological activity of chemicals to their molecular structure and physico-chemical properties. To de...

  18. A Comprehensive Mutational Analysis of the Arabidopsis Resistance Protein RPW8.2 Reveals Key Amino Acids for Defense Activation and Protein Targeting[W

    PubMed Central

    Wang, Wenming; Zhang, Yi; Wen, Yingqiang; Berkey, Robert; Ma, Xianfeng; Pan, Zhiyong; Bendigeri, Dipti; King, Harlan; Zhang, Qiong; Xiao, Shunyuan

    2013-01-01

    The Arabidopsis thaliana RESISTANCE TO POWDERY MILDEW8.2 (RPW8.2) protein is specifically targeted to the extrahaustorial membrane (EHM) encasing the haustorium, or fungal feeding structure, where RPW8.2 activates broad-spectrum resistance against powdery mildew pathogens. How RPW8.2 activates defenses at a precise subcellular locale is not known. Here, we report a comprehensive mutational analysis in which more than 100 RPW8.2 mutants were functionally evaluated for their defense and trafficking properties. We show that three amino acid residues (i.e., threonine-64, valine-68, and aspartic acid-116) are critical for RPW8.2-mediated cell death and resistance to powdery mildew (Golovinomyces cichoracearum UCSC1). Also, we reveal that two arginine (R)– or lysine (K)–enriched short motifs (i.e., R/K-R/K-x-R/K) make up the likely core EHM-targeting signals, which, together with the N-terminal transmembrane domain, define a minimal sequence of 60 amino acids that is necessary and sufficient for EHM localization. In addition, some RPW8.2 mutants localize to the nucleus and/or to a potentially novel membrane that wraps around plastids or plastid-derived stromules. Results from this study not only reveal critical amino acid elements in RPW8.2 that enable haustorium-targeted trafficking and defense, but also provide evidence for the existence of a specific, EHM-oriented membrane trafficking pathway in leaf epidermal cells invaded by powdery mildew. PMID:24151293

  19. Does investment in leaf defenses drive changes in leaf economic strategy? A focus on whole-plant ontogeny.

    PubMed

    Mason, Chase M; Donovan, Lisa A

    2015-04-01

    Leaf defenses have long been studied in the context of plant growth rate, resource availability, and optimal investment theory. Likewise, one of the central modern paradigms of plant ecophysiology, the leaf economics spectrum (LES), has been extensively studied in the context of these factors across ecological scales ranging from global species data sets to temporal shifts within individuals. Despite strong physiological links between LES strategy and leaf defenses in structure, function, and resource investment, the relationship between these trait classes has not been well explored. This study investigates the relationship between leaf defenses and LES strategy across whole-plant ontogeny in three diverse Helianthus species known to exhibit dramatic ontogenetic shifts in LES strategy, focusing primarily on physical and quantitative chemical defenses. Plants were grown under controlled environmental conditions and sampled for LES and defense traits at four ontogenetic stages. Defenses were found to shift strongly with ontogeny, and to correlate strongly with LES strategy. More advanced ontogenetic stages with more conservative LES strategy leaves had higher tannin activity and toughness in all species, and higher leaf dry matter content in two of three species. Modeling results in two species support the conclusion that changes in defenses drive changes in LES strategy through ontogeny, and in one species that changes in defenses and LES strategy are likely independently driven by ontogeny. Results of this study support the hypothesis that leaf-level allocation to defenses might be an important determinant of leaf economic traits, where high investment in defenses drives a conservative LES strategy.

  20. Do Training Programs Work? An Assessment of Pharmacists Activities in the Field of Chemical Dependency.

    ERIC Educational Resources Information Center

    Brooks, Valerie G.; Brock, Tina Penick; Ahn, Jungeun

    2001-01-01

    Seeks to determine if pharmacists who attended a chemical dependency training program were performing more chemical dependency related activities. Results reveal that participants were more likely to perform the following activities: lecture to community groups about chemical dependency; participate in a pharmacists' recovery program; provide…

  1. Brazilian Propolis: Correlation Between Chemical Composition and Antimicrobial Activity

    PubMed Central

    Salomão, Kelly; Pereira, Paulo Roberto S.; Campos, Leila C.; Borba, Cintia M.; Cabello, Pedro H.; Marcucci, Maria Cristina

    2008-01-01

    The chemical composition of ethanol extracts from samples of Brazilian propolis (EEPs) determined by HPLC and their activity against Trypanosoma cruzi, Staphylococcus aureus, Streptococcus pneumoniae, Klebisiella pneumoniae, Candida albicans, Sporothrix schenckii and Paracoccidioides brasiliensis were determined. Based on the predominant botanical origin in the region of samples' collection, the 10 extracts were separated into three groups: A (B. dracunculifolia + Auraucaria spp), B (B. dracunculifolia) and C (Araucaria spp). Analysis by the multiple regression of all the extracts together showed a positive correlation, higher concentrations leading to higher biological effect, of S. aureus with p-coumaric acid (PCUM) and 3-(4-hydroxy-3-(oxo-butenyl)-phenylacrylic acid (DHCA1) and of trypomastigotes of T. cruzi with 3,5-diprenyl-4-hydroxycinnamic acid derivative 4 (DHCA4) and 2,2-dimethyl-6-carboxyethenyl-2H-1-benzopyran (DCBEN). When the same approach was employed for each group, due to the small number of observations, the statistical test gave unreliable results. However, an overall analysis revealed for group A an association of S. aureus with caffeic acid (CAF) and dicaffeoylquinic acid 3 (CAFQ3), of S. pneumoniae with CAFQ3 and monocaffeoylquinic acid 2 (CAFQ2) and of T. cruzi also with CAFQ3. For group B, a higher activity against S. pneumoniae was associated DCBEN and for T. cruzi with CAF. For group C no association was observed between the anitmicrobial effect and any component of the extracts. The present study reinforces the relevance of PCUM and derivatives, especially prenylated ones and also of caffeolyquinic acids, on the biological activity of Brazilian propolis. PMID:18830454

  2. High sensitivity stand-off detection and quantification of chemical mixtures using an active coherent laser spectrometer (ACLaS)

    NASA Astrophysics Data System (ADS)

    MacLeod, Neil A.; Weidmann, Damien

    2016-05-01

    High sensitivity detection, identification and quantification of chemicals in a stand-off configuration is a highly sought after capability across the security and defense sector. Specific applications include assessing the presence of explosive related materials, poisonous or toxic chemical agents, and narcotics. Real world field deployment of an operational stand-off system is challenging due to stringent requirements: high detection sensitivity, stand-off ranges from centimeters to hundreds of meters, eye-safe invisible light, near real-time response and a wide chemical versatility encompassing both vapor and condensed phase chemicals. Additionally, field deployment requires a compact, rugged, power efficient, and cost-effective design. To address these demanding requirements, we have developed the concept of Active Coherent Laser Spectrometer (ACLaS), which can be also described as a middle infrared hyperspectral coherent lidar. Combined with robust spectral unmixing algorithms, inherited from retrievals of information from high-resolution spectral data generated by satellitebased spectrometers, ACLaS has been demonstrated to fulfil the above-mentioned needs. ACLaS prototypes have been so far developed using quantum cascade lasers (QCL) and interband cascade lasers (ICL) to exploit the fast frequency tuning capability of these solid state sources. Using distributed feedback (DFB) QCL, demonstration and performance analysis were carried out on narrow-band absorbing chemicals (N2O, H2O, H2O2, CH4, C2H2 and C2H6) at stand-off distances up to 50 m using realistic non cooperative targets such as wood, painted metal, and bricks. Using more widely tunable external cavity QCL, ACLaS has also been demonstrated on broadband absorbing chemicals (dichloroethane, HFC134a, ethylene glycol dinitrate and 4-nitroacetanilide solid) and on complex samples mixing narrow-band and broadband absorbers together in a realistic atmospheric background.

  3. Expression of the lipid transfer protein Ace-AMP1 in transgenic wheat enhances antifungal activity and defense responses.

    PubMed

    Roy-Barman, Subhankar; Sautter, Christof; Chattoo, Bharat B

    2006-08-01

    To enhance fungal disease resistance, wheat plants (cv. Bobwhite) were engineered to constitutively express the potent antimicrobial protein Ace-AMP1 from Allium cepa, driven by a maize ubiquitin promoter along with its first intron. The bar gene was used for selection of putative transformants on medium containing phosphinothricin (PPT). Transgene inheritance, integration and stability of expression were confirmed over two generations by PCR, Southern, northern and western blot analyses, respectively. The levels of Ace-AMP1 in different transgenic lines correlated with the transcript levels of the transgene. Up to 50% increase in resistance to Blumeria graminis f. sp. tritici was detected in detached leaf assays. In ears of transgenic wheat inoculated with Neovossia indica, Ace-AMP1 intensified expression of defense-related genes. Elevated levels of salicylic acid and of transcripts of phenylalanine ammonia lyase (PAL), glucanase (PR2) and chitinase (PR3) in the transgenic plants indicated manifestation of systemic acquired resistance (SAR). PMID:16906444

  4. The Inflammasome in Host Defense

    PubMed Central

    Chen, Gang; Pedra, Joao H.F.

    2010-01-01

    Nod-like receptors have emerged as an important family of sensors in host defense. These receptors are expressed in macrophages, dendritic cells and monocytes and play an important role in microbial immunity. Some Nod-like receptors form the inflammasome, a protein complex that activates caspase-1 in response to several stimuli. Caspase-1 activation leads to processing and secretion of pro-inflammatory cytokines such as interleukin (IL)-1β and IL-18. Here, we discuss recent advances in the inflammasome field with an emphasis on host defense. We also compare differential requirements for inflammasome activation in dendritic cells, macrophages and monocytes. PMID:22315529

  5. Over-expression of rice leucine-rich repeat protein results in activation of defense response, thereby enhancing resistance to bacterial soft rot in Chinese cabbage.

    PubMed

    Park, Young Ho; Choi, Changhyun; Park, Eun Mi; Kim, Hyo Sun; Park, Hong Jae; Bae, Shin Cheol; Ahn, Ilpyung; Kim, Min Gab; Park, Sang Ryeol; Hwang, Duk-Ju

    2012-10-01

    Pectobacterium carotovorum subsp. carotovorum causes soft rot disease in various plants, including Chinese cabbage. The simple extracellular leucine-rich repeat (eLRR) domain proteins have been implicated in disease resistance. Rice leucine-rich repeat protein (OsLRP), a rice simple eLRR domain protein, is induced by pathogens, phytohormones, and salt. To see whether OsLRP enhances disease resistance to bacterial soft rot, OsLRP was introduced into Chinese cabbage by Agrobacterium-mediated transformation. Two independent transgenic lines over-expressing OsLRP were generated and further analyzed. Transgenic lines over-expressing OsLRP showed enhanced disease resistance to bacterial soft rot compared to non-transgenic control. Bacterial growth was retarded in transgenic lines over-expressing OsLRP compared to non-transgenic controls. We propose that OsLRP confers enhanced resistance to bacterial soft rot. Monitoring expression of defense-associated genes in transgenic lines over-expressing OsLRP, two different glucanases and Brassica rapa polygalacturonase inhibiting protein 2, PDF1 were constitutively activated in transgenic lines compared to non-transgenic control. Taken together, heterologous expression of OsLRP results in the activation of defense response and enhanced resistance to bacterial soft rot.

  6. Short-term overcrowding of Atlantic cod, Gadus morhua: effects on serum-mediated antibacterial activity and transcription of glucose transport and antioxidant defense related genes.

    PubMed

    Caipang, Christopher Marlowe A; Brinchmann, Monica F; Kiron, Viswanath

    2008-12-01

    Serum-mediated control of Listonella anguillarum and transcriptional profiles of selected glucose transport and antioxidant defense genes, following short-term overcrowding in Atlantic cod, Gadus morhua were determined. Fish were subjected to overcrowding by reducing the water level in the tank for 1 h and this was repeated thrice over a 12 h period. Blood samples were collected before overcrowding (initial group) and at 2, 24 and 72 h post-crowding. The sera from fish obtained at 2 h post-crowding caused a significant reduction in L. anguillarum counts compared to the initial samples. There was a transcriptional upregulation of the glucose transport-4 and glyceraldehyde-3-phosphate dehydrogenase genes at 2 h after crowding. Gene transcripts of the antioxidant enzymes, Cu/Zn superoxide dismutase (Cu/Zn SOD), catalase and phospholipid hydroperoxide glutathione peroxidase also significantly increased at 2 h post-crowding, but thereafter they returned to their pre-crowding levels with the exception of Cu/Zn SOD that remained significantly higher than the initial group until 72 h. Thus, short-term overcrowding of Atlantic cod leads to a transient enhancement of in vitro serum antibacterial activity and enhanced transcriptional activity of glucose transport and antioxidant defense genes.

  7. PREDICTING TOXICOLOGICAL ENDPOINTS OF CHEMICALS USING QUANTITATIVE STRUCTURE-ACTIVITY RELATIONSHIPS (QSARS)

    EPA Science Inventory

    Quantitative structure-activity relationships (QSARs) are being developed to predict the toxicological endpoints for untested chemicals similar in structure to chemicals that have known experimental toxicological data. Based on a very large number of predetermined descriptors, a...

  8. Priming of antiherbivore defensive responses in plants.

    PubMed

    Kim, Jinwon; Felton, Gary W

    2013-06-01

    Defense priming is defined as increased readiness of defense induction. A growing body of literature indicates that plants (or intact parts of a plant) are primed in anticipation of impending environmental stresses, both biotic and abiotic, and upon the following stimulus, induce defenses more quickly and strongly. For instance, some plants previously exposed to herbivore-inducible plant volatiles (HIPVs) from neighboring plants under herbivore attack show faster or stronger defense activation and enhanced insect resistance when challenged with secondary insect feeding. Research on priming of antiherbivore defense has been limited to the HIPV-mediated mechanism until recently, but significant advances were made in the past three years, including non-HIPV-mediated defense priming, epigenetic modifications as the molecular mechanism of priming, and others. It is timely to consider the advances in research on defense priming in the plant-insect interactions.

  9. Formation and decomposition of chemically activated and stabilized hydrazine.

    PubMed

    Asatryan, Rubik; Bozzelli, Joseph W; da Silva, Gabriel; Swinnen, Saartje; Nguyen, Minh Tho

    2010-06-01

    Recombination of two amidogen radicals, NH(2) (X(2)B1), is relevant to hydrazine formation, ammonia oxidation and pyrolysis, nitrogen reduction (fixation), and a variety of other N/H/X combustion, environmental, and interstellar processes. We have performed a comprehensive analysis of the N(2)H(4) potential energy surface, using a variety of theoretical methods, with thermochemical kinetic analysis and master equation simulations used to treat branching to different product sets in the chemically activated NH(2) + NH(2) process. For the first time, iminoammonium ylide (NH(3)NH), the less stable isomer of hydrazine, is involved in the kinetic modeling of N(2)H(4). A new, low-energy pathway is identified for the formation of NH(3) plus triplet NH, via initial production of NH(3)NH followed by singlet-triplet intersystem crossing. This new reaction channel results in the formation of dissociated products at a relatively rapid rate at even moderate temperatures and above. A further novel pathway is described for the decomposition of activated N(2)H(4), which eventually leads to the formation of the simple products N(2) + 2H(2), via H(2) elimination to cis-N(2)H(2). This process, termed as "dihydrogen catalysis", may have significant implications in the formation and decomposition chemistry of hydrazine and ammonia in diverse environments. In this mechanism, stereoselective attack of cis-N(2)H(2) by molecular hydrogen results in decomposition to N(2) with a fairly low barrier. The reverse termolecular reaction leading to the gas-phase formation of cis-N(2)H(2) + H(2) achieves non-heterogeneous catalytic nitrogen fixation with a relatively low activation barrier (77 kcal mol(-1)), much lower than the 125 kcal mol(-1) barrier recently reported for bimolecular addition of H(2) to N(2). This termolecular reaction is an entropically disfavored path, but it does describe a new means of activating the notoriously unreactive N(2). We design heterogeneous analogues of this

  10. Infrared point sensors for homeland defense applications

    NASA Astrophysics Data System (ADS)

    Thomas, Ross C.; Carter, Michael T.; Homrighausen, Craig L.

    2004-03-01

    We report recent progress toward the development of infrared point sensors for the detection of chemical warfare agents and explosive related chemicals, which pose a significant threat to both health and environment. Technical objectives have focused on the development of polymer sorbents to enhance the infrared response of these hazardous organic compounds. For example, infrared point sensors which part-per-billion detection limits have been developed that rapidlypartition chemical warfare agents and explosive related chemicals into polymer thin films with desirable chemical and physical properties. These chemical sensors demonstrate novel routes to reversible sensing of hazardous organic compounds. The development of small, low-power, sensitive, and selective instruments employing these chemical sensors would enhance the capabilities of federal, state, and local emergency response to incidents involving chemical terrorism. Specific applications include chemical defense systems for military personnel and homeland defense, environmental monitors for remediation and demilitarization, and point source detectors for emergency and maintenance response teams.

  11. Chemical and thermal modulation of molecular motor activities

    NASA Astrophysics Data System (ADS)

    Hong, Weili

    Molecular motors of kinesin and dynein families are responsible for various intracellular activities, from long distance movement of organelles, vesicles, protein complexes, and mRNAs to powering mitotic processes. They can take nanometer steps using chemical energy from the hydrolysis of ATP (adenosine triphosphate), and their dysfunction is involved in many neurodegenerative diseases that require long distance transport of cargos. Here I report on the study of the properties of molecular motors at a single-molecule level using optical trappings. I first studied the inhibition properties of kinesin motors by marine natural compound adociasulfates. I showed that adociasulfates compete with microtubules for binding to kinesins and thus inhibit kinesins' activity. Although adociasulfates are a strong inhibitor for all kinesin members, they show a much higher inhibition effect for conventional kinesins than for mitotic kinesins. Thus adociasulfates can be used to specifically inhibit conventional kinesins. By comparing the inhibition of kinesins by two structurally similar adociasulfates, one can see that the negatively charged sulfate residue of adociasulfates can be replaced by other negative residues and thus make it possible for adociasulfate-derived compounds to be more cell permeable. Kinesins and dyneins move cargos towards opposite directions along a microtubule. Cargos with both kinesins and dyneins attached often move bidirectionally due to undergoing a tug-of-war between the oppositely moving kinesin and dynein motors. Here I studied the effect of temperature on microtubule-based kinesin and dynein motor transport. While kinesins' and dyneins' velocities are closely matched above 15 °C, below this temperature the dyneins' velocity decreases much faster than the kinesins'. The kinesins' and dyneins' forces do not measurably change with temperature. The results suggest that temperature has significant effects on bidirectional transport and can be used to

  12. Plant polyphenols: chemical properties, biological activities, and synthesis.

    PubMed

    Quideau, Stéphane; Deffieux, Denis; Douat-Casassus, Céline; Pouységu, Laurent

    2011-01-17

    Eating five servings of fruits and vegetables per day! This is what is highly recommended and heavily advertised nowadays to the general public to stay fit and healthy! Drinking green tea on a regular basis, eating chocolate from time to time, as well as savoring a couple of glasses of red wine per day have been claimed to increase life expectancy even further! Why? The answer is in fact still under scientific scrutiny, but a particular class of compounds naturally occurring in fruits and vegetables is considered to be crucial for the expression of such human health benefits: the polyphenols! What are these plant products really? What are their physicochemical properties? How do they express their biological activity? Are they really valuable for disease prevention? Can they be used to develop new pharmaceutical drugs? What recent progress has been made toward their preparation by organic synthesis? This Review gives answers from a chemical perspective, summarizes the state of the art, and highlights the most significant advances in the field of polyphenol research.

  13. Two-phase flow in a chemically active porous medium

    SciTech Connect

    Darmon, Alexandre Dauchot, Olivier; Benzaquen, Michael; Salez, Thomas

    2014-12-28

    We study the problem of the transformation of a given reactant species into an immiscible product species, as they flow through a chemically active porous medium. We derive the equation governing the evolution of the volume fraction of the species, in a one-dimensional macroscopic description, identify the relevant dimensionless numbers, and provide simple models for capillary pressure and relative permeabilities, which are quantities of crucial importance when tackling multiphase flows in porous media. We set the domain of validity of our models and discuss the importance of viscous coupling terms in the extended Darcy’s law. We investigate numerically the steady regime and demonstrate that the spatial transformation rate of the species along the reactor is non-monotonous, as testified by the existence of an inflection point in the volume fraction profiles. We obtain the scaling of the location of this inflection point with the dimensionless lengths of the problem. Eventually, we provide key elements for optimization of the reactor.

  14. Plant polyphenols: chemical properties, biological activities, and synthesis.

    PubMed

    Quideau, Stéphane; Deffieux, Denis; Douat-Casassus, Céline; Pouységu, Laurent

    2011-01-17

    Eating five servings of fruits and vegetables per day! This is what is highly recommended and heavily advertised nowadays to the general public to stay fit and healthy! Drinking green tea on a regular basis, eating chocolate from time to time, as well as savoring a couple of glasses of red wine per day have been claimed to increase life expectancy even further! Why? The answer is in fact still under scientific scrutiny, but a particular class of compounds naturally occurring in fruits and vegetables is considered to be crucial for the expression of such human health benefits: the polyphenols! What are these plant products really? What are their physicochemical properties? How do they express their biological activity? Are they really valuable for disease prevention? Can they be used to develop new pharmaceutical drugs? What recent progress has been made toward their preparation by organic synthesis? This Review gives answers from a chemical perspective, summarizes the state of the art, and highlights the most significant advances in the field of polyphenol research. PMID:21226137

  15. Adsorption of copper cyanide on chemically active adsorbents

    SciTech Connect

    Lee, J.S.; Deorkar, N.V.; Tavlarides, L.L.

    1998-07-01

    An inorganic chemically active adsorbent (ICAA), SG(1)-TEPA (tetraethylenepentaamine)-propyl, is developed for removal, recovery, and recycling of copper cyanide from industrial waste streams. Equilibrium studies are executed to determine and model adsorption of the copper cyanide complex from aqueous solutions in a batch and packed column. It appears that adsorption is dependent on anionic copper cyanide species and the basicity of the ligand. Aqueous-phase equilibrium modeling shows that monovalent (Cu(CN){sub 2}{sup {minus}}), divalent (Cu(CN){sub 3}{sup 2{minus}}), and trivalent (Cu(CN){sub 4}{sup 3{minus}}) species of copper cyanide exist in the solution, depending on the pH and the concentration of total cyanide ions. Batch adsorption data are modeled using a modified multicomponent Langmuir isotherm which includes aqueous-phase speciation and basicity of the SG(1)-TEPA-propyl. This developed model is applied with a mass balance equation to describe the adsorption of copper cyanide complexes in a packed column.

  16. 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

  17. Cotton WRKY1 mediates the plant defense-to-development transition during infection of cotton by Verticillium dahliae by activating JASMONATE ZIM-DOMAIN1 expression.

    PubMed

    Li, Chao; He, Xin; Luo, Xiangyin; Xu, Li; Liu, Linlin; Min, Ling; Jin, Li; Zhu, Longfu; Zhang, Xianlong

    2014-12-01

    Plants have evolved an elaborate signaling network to ensure an appropriate level of immune response to meet the differing demands of developmental processes. Previous research has demonstrated that DELLA proteins physically interact with JASMONATE ZIM-DOMAIN1 (JAZ1) and dynamically regulate the interaction of the gibberellin (GA) and jasmonate (JA) signaling pathways. However, whether and how the JAZ1-DELLA regulatory node is regulated at the transcriptional level in plants under normal growth conditions or during pathogen infection is not known. Here, we demonstrate multiple functions of cotton (Gossypium barbadense) GbWRKY1 in the plant defense response and during development. Although GbWRKY1 expression is induced rapidly by methyl jasmonate and infection by Verticillium dahliae, our results show that GbWRKY1 is a negative regulator of the JA-mediated defense response and plant resistance to the pathogens Botrytis cinerea and V. dahliae. Under normal growth conditions, GbWRKY1-overexpressing lines displayed GA-associated phenotypes, including organ elongation and early flowering, coupled with the down-regulation of the putative targets of DELLA. We show that the GA-related phenotypes of GbWRKY1-overexpressing plants depend on the constitutive expression of Gossypium hirsutum GhJAZ1. We also show that GhJAZ1 can be transactivated by GbWRKY1 through TGAC core sequences, and the adjacent sequences of this binding site are essential for binding specificity and affinity to GbWRKY1, as revealed by dual-luciferase reporter assays and electrophoretic mobility shift assays. In summary, our data suggest that GbWRKY1 is a critical regulator mediating the plant defense-to-development transition during V. dahliae infection by activating JAZ1 expression.

  18. Thermoregulatory defense mechanisms.

    PubMed

    Sessler, Daniel I

    2009-07-01

    Core body temperature is normally tightly regulated by an effective thermoregulatory system. Thermoregulatory control is sometimes impaired by serious illness, but more typically remains intact. The primary autonomic defenses against heat are sweating and active precapillary vasodilation; the primary autonomic defenses against cold are arteriovenous shunt vasoconstriction and shivering. The core temperature triggering each response defines its activation threshold. Temperatures between the sweating and vasoconstriction thresholds define the inter-threshold range. The shivering threshold is usually a full 1 degrees C below the vasoconstriction threshold and is therefore a "last resort" response. Both vasoconstriction and shivering are associated with autonomic and hemodynamic activation; and each response is effective, thus impeding induction of therapeutic hypothermia. It is thus helpful to accompany core cooling with drugs that pharmacologically induce a degree of thermal tolerance. No perfect drug or drug combination has been identified. Anesthetics, for example, induce considerable tolerance, but are rarely suitable. Meperidine-especially in combination with buspirone-is especially effective while provoking only modest toxicity. The combination of buspirone and dexmedetomidine is comparably effective while avoiding the respiratory depression association with opioid administration.

  19. ABA is an essential signal for plant resistance to pathogens affecting JA biosynthesis and the activation of plant defenses in Arabidopsis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Plant defense responses have been studied through a limited number of models that may have constrained our view of plant-pathogen interactions. Discovery of new defense mechanisms should be favored by broadening the range of pathogens under study. With this aim, Arabidopsis defense response to the ‘...

  20. Heat-activated Plasmonic Chemical Sensors for Harsh Environments

    SciTech Connect

    Carpenter, Michael; Oh, Sang-Hyun

    2015-12-01

    A passive plasmonics based chemical sensing system to be used in harsh operating environments was investigated and developed within this program. The initial proposed technology was based on combining technologies developed at the SUNY Polytechnic Institute Colleges of Nanoscale Science and Engineering (CNSE) and at the University of Minnesota (UM). Specifically, a passive wireless technique developed at UM was to utilize a heat-activated plasmonic design to passively harvest the thermal energy from within a combustion emission stream and convert this into a narrowly focused light source. This plasmonic device was based on a bullseye design patterned into a gold film using focused ion beam methods (FIB). Critical to the design was the use of thermal stabilizing under and overlayers surrounding the gold film. These stabilizing layers were based on both atomic layer deposited films as well as metal laminate layers developed by United Technologies Aerospace Systems (UTAS). While the bullseye design was never able to be thermally stabilized for operating temperatures of 500oC or higher, an alternative energy harvesting design was developed by CNSE within this program. With this new development, plasmonic sensing results are presented where thermal energy is harvested using lithographically patterned Au nanorods, replacing the need for an external incident light source. Gas sensing results using the harvested thermal energy are in good agreement with sensing experiments, which used an external incident light source. Principal Component Analysis (PCA) was used to reduce the wavelength parameter space from 665 variables down to 4 variables with similar levels of demonstrated selectivity. The method was further improved by patterning rods which harvested energy in the near infrared, which led to a factor of 10 decrease in data acquisition times as well as demonstrated selectivity with a reduced wavelength data set. The combination of a plasmonic-based energy harvesting

  1. Fortifications and underground nuclear defense shelters for NATO troops

    SciTech Connect

    Miller, D.

    1985-01-01

    Improvements in NATO's conventional, chemical, and nuclear defenses are clearly needed; but constraints on changing NATO's forces are severe. Better NATO defenses must be achieved at a low economic cost, without changing NATO strategy, without adding more active duty troops or TNW, and without threatening the Soviets. Simple forms of field fortifications would improve the defensive strength of NATO forces without violating these constraints. PGMs are extremely powerful weapons that are much more effective when their operators enjoy the protection fortifications offer. Because the mission of defending fortifications and firing PGMs is simple relative to fighting a mobile war with armored vehicles, greater reliance could be placed on cheaper and more numerous West European reserves and militia forces. A simple corrugated pipe shelter buried seven feet underground would protect men against TNW as large as 100 KT striking as close as 600 meters. Since underground shelters seal air-tight they provide protection from chemical and biological weapons. A fixed defense program would be very affordable, costing around $2 billion. In addition to being much less expensive, shelters and fortifications are also attractive because they do not suffer from problems of poor reliability associated with most new high technology weapons.

  2. Heterotrimeric G Proteins Serve as a Converging Point in Plant Defense Signaling Activated by Multiple Receptor-Like Kinases1[C][W][OA

    PubMed Central

    Liu, Jinman; Ding, Pingtao; Sun, Tongjun; Nitta, Yukino; Dong, Oliver; Huang, Xingchuan; Yang, Wei; Li, Xin; Botella, José Ramón; Zhang, Yuelin

    2013-01-01

    In fungi and metazoans, extracellular signals are often perceived by G-protein-coupled receptors (GPCRs) and transduced through heterotrimeric G-protein complexes to downstream targets. Plant heterotrimeric G proteins are also involved in diverse biological processes, but little is known about their upstream receptors. Moreover, the presence of bona fide GPCRs in plants is yet to be established. In Arabidopsis (Arabidopsis thaliana), heterotrimeric G protein consists of one Gα subunit (G PROTEIN α-SUBUNIT1), one Gβ subunit (ARABIDOPSIS G PROTEIN β-SUBUNIT1 [AGB1]), and three Gγs subunits (ARABIDOPSIS G PROTEIN γ-SUBUNIT1 [AGG1], AGG2, and AGG3). We identified AGB1 from a suppressor screen of BAK1-interacting receptor-like kinase1-1 (bir1-1), a mutant that activates cell death and defense responses mediated by the receptor-like kinase (RLK) SUPPRESSOR OF BIR1-1. Mutations in AGB1 suppress the cell death and defense responses in bir1-1 and transgenic plants overexpressing SUPPRESSOR OF BIR1-1. In addition, agb1 mutant plants were severely compromised in immunity mediated by three other RLKs, FLAGELLIN-SENSITIVE2 (FLS2), Elongation Factor-TU RECEPTOR (EFR), and CHITIN ELICITOR RECEPTOR KINASE1 (CERK1), respectively. By contrast, G PROTEIN α-SUBUNIT1 is not required for either cell death in bir1-1 or pathogen-associated molecular pattern-triggered immunity mediated by FLS2, EFR, and CERK1. Further analysis of agg1 and agg2 mutant plants indicates that AGG1 and AGG2 are also required for pathogen-associated molecular pattern-triggered immune responses mediated by FLS2, EFR, and CERK1, as well as cell death and defense responses in bir1-1. We hypothesize that the Arabidopsis heterotrimeric G proteins function as a converging point of plant defense signaling by mediating responses initiated by multiple RLKs, which may fulfill equivalent roles to GPCRs in fungi and animals. PMID:23424249

  3. The 5’-AMP-Activated Protein Kinase (AMPK) Is Involved in the Augmentation of Antioxidant Defenses in Cryopreserved Chicken Sperm

    PubMed Central

    Nguyen, Thi Mong Diep; Seigneurin, François; Froment, Pascal; Combarnous, Yves; Blesbois, Elisabeth

    2015-01-01

    Semen cryopreservation is a unique tool for the management of animal genetic diversity. However, the freeze-thaw process causes biochemical and physical alterations which make difficult the restoration of sperm energy-dependent functions needed for fertilization. 5’-AMP activated protein kinase (AMPK) is a key sensor and regulator of intracellular energy metabolism. Mitochondria functions are known to be severely affected during sperm cryopreservation with deleterious oxidative and peroxidative effects leading to cell integrity and functions damages. The aim of this study was thus to examine the role of AMPK on the peroxidation/antioxidant enzymes defense system in frozen-thawed sperm and its consequences on sperm functions. Chicken semen was diluted in media supplemented with or without AMPK activators (AICAR or Metformin [MET]) or inhibitor (Compound C [CC]) and then cryopreserved. AMPKα phosphorylation, antioxidant enzymes activities, mitochondrial potential, ATP, citrate, viability, acrosome reaction ability (AR) and various motility parameters were negatively affected by the freeze-thaw process while reactive oxygen species (ROS) production, lipid peroxidation (LPO) and lactate concentration were dramatically increased. AICAR partially restored superoxide dismutase (SOD), Glutathione Peroxidase (GPx) and Glutathione Reductase (GR), increased ATP, citrate, and lactate concentration and subsequently decreased the ROS and LPO (malondialdehyde) in frozen-thawed semen. Motility parameters were increased (i.e., + 23% for motility, + 34% for rapid sperm) as well as AR (+ 100%). MET had similar effects as AICAR except that catalase activity was restored and that ATP and mitochondrial potential were further decreased. CC showed effects opposite to AICAR on SOD, ROS, LPO and AR and motility parameters. Taken together, our results strongly suggest that, upon freeze-thaw process, AMPK stimulated intracellular anti-oxidative defense enzymes through ATP regulation, thus

  4. UV-A Irradiation Activates Nrf2-Regulated Antioxidant Defense and Induces p53/Caspase3-Dependent Apoptosis in Corneal Endothelial Cells

    PubMed Central

    Liu, Cailing; Vojnovic, Dijana; Kochevar, Irene E.; Jurkunas, Ula V.

    2016-01-01

    Purpose To examine whether Nrf2-regulated antioxidant defense and p53 are activated in human corneal endothelial cells (CEnCs) by environmental levels of ultraviolet A (UV-A), a known stimulator of oxidative stress. Methods Immortalized human CEnCs (HCEnCi) were exposed to UV-A fluences of 2.5, 5, 10, or 25 J/cm2, then allowed to recover for 3 to 24 hours. Control HCEnCi did not receive UV-A. Reactive oxygen species (ROS) were measured using H2DCFDA. Cell cytotoxicity was evaluated by lactate dehydrogenase (LDH) release. Levels of Nrf2, HO-1, NQO-1, p53, and caspase3 were detected by immunnoblotting or real-time PCR. Activated caspase3 was measured by immunoblotting and a fluorescence assay. Results Exposure of HCEnCi to 5, 10, and 25 J/cm2 UV-A increased ROS levels compared with controls. Nrf2, HO-1, and NQO-1 mRNA increased 1.7- to 3.2-fold at 3 and 6 hours after irradiation with 2.5 and 5 J/cm2 UV-A. At 6 hours post irradiation, UV-A (5 J/cm2) enhanced nuclear Nrf2 translocation. At 24 hours post treatment, UV-A (5, 10, and 25 J/cm2) produced a 1.8- to 2.8-fold increase in phospho-p53 and a 2.6- to 6.0-fold increase in activated caspase3 compared with controls, resulting in 20% to 42% cell death. Conclusions Lower fluences of UV-A induce Nrf2-regulated antioxidant defense and higher fluences activate p53 and caspase3, indicating that even near-environmental levels of UV-A may affect normal CEnCs. This data suggest that UV-A may especially damage cells deficient in antioxidant defense, and thus may be involved in the etiology of Fuchs' endothelial corneal dystrophy (FECD). PMID:27127932

  5. Synergistic activation of estrogen receptor with combinations of environmental chemicals

    SciTech Connect

    Arnold, S.F.; Klotz, D.M.; Collins, B.M.

    1996-06-07

    Certain chemicals in the environment are estrogenic. The low potencies of the compounds, when studied singly, suggest that they may have little effect on biological systems. The estrogenic potencies of combinations of such chemicals were screened in a simple yeast estrogen potencies of combination of such chemicals were screened in a simple yeast estrogen systems (YES) containing human estrogen receptor (hER). Combinations of two weak environmental estrogens, such as dieldrin, endosulfan, or toxaphene, were 100 times as potent in hER-mediated transactivation as any chemical alone. Hydroxylated polychlorinated biphenyls shown previously to synergistically alter sexual development in turtles also synergized in the YES. The synergistic interaction of chemical mixtures with the estrogen receptor may have profound environmental implications. These results may represent a previously uncharacterized level of regulation of estrogen-associated responses. 32 refs., 3 figs., 3 tabs.

  6. 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

  7. Advanced deposition model for thermal activated chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Cai, Dang

    Thermal Activated Chemical Vapor Deposition (TACVD) is defined as the formation of a stable solid product on a heated substrate surface from chemical reactions and/or dissociation of gaseous reactants in an activated environment. It has become an essential process for producing solid film, bulk material, coating, fibers, powders and monolithic components. Global market of CVD products has reached multi billions dollars for each year. In the recent years CVD process has been extensively used to manufacture semiconductors and other electronic components such as polysilicon, AlN and GaN. Extensive research effort has been directed to improve deposition quality and throughput. To obtain fast and high quality deposition, operational conditions such as temperature, pressure, fluid velocity and species concentration and geometry conditions such as source-substrate distance need to be well controlled in a CVD system. This thesis will focus on design of CVD processes through understanding the transport and reaction phenomena in the growth reactor. Since the in situ monitor is almost impossible for CVD reactor, many industrial resources have been expended to determine the optimum design by semi-empirical methods and trial-and-error procedures. This approach has allowed the achievement of improvements in the deposition sequence, but begins to show its limitations, as this method cannot always fulfill the more and more stringent specifications of the industry. To resolve this problem, numerical simulation is widely used in studying the growth techniques. The difficulty of numerical simulation of TACVD crystal growth process lies in the simulation of gas phase and surface reactions, especially the latter one, due to the fact that very limited kinetic information is available in the open literature. In this thesis, an advanced deposition model was developed to study the multi-component fluid flow, homogeneous gas phase reactions inside the reactor chamber, heterogeneous surface

  8. Biotin-Binding Proteins in the Defense of Mushrooms against Predators and Parasites

    PubMed Central

    Bleuler-Martinez, Silvia; Schmieder, Stefanie; Aebi, Markus

    2012-01-01

    Tamavidins are fungal biotin-binding proteins (BBPs) displaying antifungal activity against phytopathogens. Here we show high toxicity of tamavidins toward nematodes, insects, and amoebae. As these organisms represent important phyla of fungal predators and parasites, we propose that BBPs are part of the chemical defense system of fungi. PMID:23001676

  9. Elucidating induced plant defenses: the use of targeted metabolomics as a bridge from elicitation to response

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Dynamic plant defense responses to biotic attack involve the perception of specific biochemical elicitors associated with the offending agent, activation of signaling cascades, and the production of small molecules with complex protective roles. Chemical analyses are essential empirical tools for el...

  10. 32 CFR 174.16 - Real property containing explosive or chemical agent hazards.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... chemical agent hazards from past DoD military munitions-related or chemical warfare-related activities... 32 National Defense 1 2014-07-01 2014-07-01 false Real property containing explosive or chemical... REALIGNMENT Environmental Matters § 174.16 Real property containing explosive or chemical agent hazards....

  11. 32 CFR 174.16 - Real property containing explosive or chemical agent hazards.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... chemical agent hazards from past DoD military munitions-related or chemical warfare-related activities... 32 National Defense 1 2013-07-01 2013-07-01 false Real property containing explosive or chemical... REALIGNMENT Environmental Matters § 174.16 Real property containing explosive or chemical agent hazards....

  12. 32 CFR 174.16 - Real property containing explosive or chemical agent hazards.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... chemical agent hazards from past DoD military munitions-related or chemical warfare-related activities... 32 National Defense 1 2012-07-01 2012-07-01 false Real property containing explosive or chemical... REALIGNMENT Environmental Matters § 174.16 Real property containing explosive or chemical agent hazards....

  13. 32 CFR 174.16 - Real property containing explosive or chemical agent hazards.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... chemical agent hazards from past DoD military munitions-related or chemical warfare-related activities... 32 National Defense 1 2011-07-01 2011-07-01 false Real property containing explosive or chemical... REALIGNMENT Environmental Matters § 174.16 Real property containing explosive or chemical agent hazards....

  14. Chemical constituents and antihistamine activity of Bixa orellana leaf extract

    PubMed Central

    2013-01-01

    Background Bixa orellana L. has been traditionally used in Central and South America to treat a number of ailments, including internal inflammation, and in other tropical countries like Malaysia as treatment for gastric ulcers and stomach discomfort. The current study aimed to determine the major chemical constituents of the aqueous extract of B. orellana (AEBO) and to evaluate the antihistamine activity of AEBO during acute inflammation induced in rats. Methods Acute inflammation was produced by subplantar injection of 0.1 mL of 0.1% histamine into the right hind paw of each rat in the control and treatment groups. The degree of edema was measured before injection and at the time points of 30, 60, 120, 180, 240 and 300 min after injection. Changes of peritoneal vascular permeability were studied using Evans blue dye as a detector. Vascular permeability was evaluated by the amount of dye leakage into the peritoneal cavity in rats. To evaluate the inhibitory effect of AEBO on biochemical mediators of vascular permeability, the levels of nitric oxide (NO) and vascular endothelial growth factor (VEGF) were determined in histamine-treated paw tissues. The major constituents of AEBO were determined by gas chromatography–mass spectrometry (GC-MS) analysis. Results AEBO produced a significant inhibition of histamine-induced paw edema starting at 60 min time point, with maximal percentage of inhibition (60.25%) achieved with a dose of 150 mg/kg of AEBO at 60 min time point. Up to 99% of increased peritoneal vascular permeability produced by histamine was successfully suppressed by AEBO. The expression of biochemical mediators of vascular permeability, NO and VEGF, was also found to be downregulated in the AEBO treated group. Gas chromatography–mass spectrometry (GC-MS) analysis revealed that the major constituent in AEBO was acetic acid. Conclusions The experimental findings demonstrated that the anti-inflammatory activity of AEBO was due to its inhibitory

  15. Combined Chemical Activation and Fenton Degradation to Convert Waste Polyethylene into High-Value Fine Chemicals.

    PubMed

    Chow, Cheuk-Fai; Wong, Wing-Leung; Ho, Keith Yat-Fung; Chan, Chung-Sum; Gong, Cheng-Bin

    2016-07-01

    Plastic waste is a valuable organic resource. However, proper technologies to recover usable materials from plastic are still very rare. Although the conversion/cracking/degradation of certain plastics into chemicals has drawn much attention, effective and selective cracking of the major waste plastic polyethylene is extremely difficult, with degradation of C-C/C-H bonds identified as the bottleneck. Pyrolysis, for example, is a nonselective degradation method used to crack plastics, but it requires a very high energy input. To solve the current plastic pollution crisis, more effective technologies are needed for converting plastic waste into useful substances that can be fed into the energy cycle or used to produce fine chemicals for industry. In this study, we demonstrate a new and effective chemical approach by using the Fenton reaction to convert polyethylene plastic waste into carboxylic acids under ambient conditions. Understanding the fundamentals of this new chemical process provides a possible protocol to solve global plastic-waste problems.

  16. Preparation of activated carbon from cherry stones by chemical activation with ZnCl 2

    NASA Astrophysics Data System (ADS)

    Olivares-Marín, M.; Fernández-González, C.; Macías-García, A.; Gómez-Serrano, V.

    2006-06-01

    Cherry stones (CS), an industrial product generated abundantly in the Valle del Jerte (Cáceres province, Spain), were used as precursor in the preparation of activated carbon by chemical activation with ZnCl 2. The influence of process variables such as the carbonisation temperature and the ZnCl 2:CS ratio (impregnation ratio) on textural and chemical-surface properties of the products obtained was studied. Such products were characterised texturally by adsorption of N 2 at -196 °C, mercury porosimetry and density measurements. Information on the surface functional groups and structures of the carbons was provided by FT-IR spectroscopy. Activated carbon with a high development of surface area and porosity is prepared. When using the 4:1 impregnation ratio, the specific surface area (BET) of the resultant carbon is as high as 1971 m 2 g -1. The effect of the increase in the impregnation ratio on the porous structure of activated carbon is stronger than that of the rise in the carbonisation temperature, whereas the opposite applies to the effect on the surface functional groups and structures.

  17. Active targeting in a random porous medium by chemical swarm robots with secondary chemical signaling

    NASA Astrophysics Data System (ADS)

    Grančič, Peter; Štěpánek, František

    2011-08-01

    The multibody dynamics of a system of chemical swarm robots in a porous environment is investigated. The chemical swarm robots are modeled as Brownian particles capable of delivering an encapsulated chemical payload toward a given target location and releasing it in response to an external stimulus. The presence of chemical signals (chemo-attractant) in the system plays a crucial role in coordinating the collective movement of the particles via chemotaxis. For a number of applications, such as distributed chemical processing and targeted drug delivery, the understanding of factors that govern the collective behavior of the particles, especially their ability to localize a given target, is of immense importance. A hybrid modeling methodology based on the combination of the Brownian dynamics method and diffusion problem coupled through the chemotaxis phenomena is used to analyze the impact of a varying signaling threshold and the strength of chemotaxis on the ability of the chemical robots to fulfill their target localization mission. The results demonstrate that the selected performance criteria (the localization half time and the success rate) can be improved when an appropriate signaling process is chosen. Furthermore, for an optimum target localization strategy, the topological complexity of the porous environment needs to be reflected.

  18. Trichoderma-plant root colonization: escaping early plant defense responses and activation of the antioxidant machinery for saline stress tolerance.

    PubMed

    Brotman, Yariv; Landau, Udi; Cuadros-Inostroza, Álvaro; Tohge, Takayuki; Takayuki, Tohge; Fernie, Alisdair R; Chet, Ilan; Viterbo, Ada; Willmitzer, Lothar

    2013-03-01

    Trichoderma spp. are versatile opportunistic plant symbionts which can colonize the apoplast of plant roots. Microarrays analysis of Arabidopsis thaliana roots inoculated with Trichoderma asperelloides T203, coupled with qPCR analysis of 137 stress responsive genes and transcription factors, revealed wide gene transcript reprogramming, proceeded by a transient repression of the plant immune responses supposedly to allow root colonization. Enhancement in the expression of WRKY18 and WRKY40, which stimulate JA-signaling via suppression of JAZ repressors and negatively regulate the expression of the defense genes FMO1, PAD3 and CYP71A13, was detected in Arabidopsis roots upon Trichoderma colonization. Reduced root colonization was observed in the wrky18/wrky40 double mutant line, while partial phenotypic complementation was achieved by over-expressing WRKY40 in the wrky18 wrky40 background. On the other hand increased colonization rate was found in roots of the FMO1 knockout mutant. Trichoderma spp. stimulate plant growth and resistance to a wide range of adverse environmental conditions. Arabidopsis and cucumber (Cucumis sativus L.) plants treated with Trichoderma prior to salt stress imposition show significantly improved seed germination. In addition, Trichoderma treatment affects the expression of several genes related to osmo-protection and general oxidative stress in roots of both plants. The MDAR gene coding for monodehydroascorbate reductase is significantly up-regulated and, accordingly, the pool of reduced ascorbic acid was found to be increased in Trichoderma treated plants. 1-Aminocyclopropane-1-carboxylate (ACC)-deaminase silenced Trichoderma mutants were less effective in providing tolerance to salt stress, suggesting that Trichoderma, similarly to ACC deaminase producing bacteria, can ameliorate plant growth under conditions of abiotic stress, by lowering ameliorating increases in ethylene levels as well as promoting an elevated antioxidative capacity.

  19. METABOLISM AND METABOLIC ACTIVATION OF CHEMICALS: IN-SILICO SIMULATION

    EPA Science Inventory

    The role of metabolism in prioritizing chemicals according to their potential adverse health effects is extremely important because innocuous parents can be transformed into toxic metabolites. This work presents the TIssue MEtabolism Simulator (TIMES) platform for simulating met...

  20. Hot-wire detector for chemically active materials used in gas chromatography

    NASA Technical Reports Server (NTRS)

    1966-01-01

    Hot-filament detector analyzes chemically active materials used in gas chromatography. The detector reacts chemically with the effluent vapors in the gas chromatographic apparatus to change the electrical resistance of the filament as a function of the affluent composition. Due to the changes produced by chemical action on the filament, the system is often calibrated.

  1. Genetic variation of lodgepole pine, Pinus contorta var. latifolia, chemical and physical defenses that affect mountain pine beetle, Dendroctonus ponderosae, attack and tree mortality.

    PubMed

    Ott, Daniel S; Yanchuk, Alvin D; Huber, Dezene P W; Wallin, Kimberly F

    2011-09-01

    Plant secondary chemistry is determined by both genetic and environmental factors, and while large intraspecific variation in secondary chemistry has been reported frequently, the levels of genetic variation of many secondary metabolites in forest trees in the context of potential resistance against pests have been rarely investigated. We examined the effect of tree genotype and environment/site on the variation in defensive secondary chemistry of lodgepole pine, Pinus contorta var. latifolia, against the fungus, Grosmannia clavigera (formerly known as Ophiostoma clavigerum), associated with the mountain pine beetle, Dendroctonus ponderosae. Terpenoids were analyzed in phloem samples from 887, 20-yr-old trees originating from 45 half-sibling families planted at two sites. Samples were collected both pre- and post-inoculation with G. clavigera. Significant variation in constitutive and induced terpenoid compounds was attributed to differences among families. The response to the challenge inoculation with G. clavigera was strong for some individual compounds, but primarily for monoterpenoids. Environment (site) also had a significant effect on the accumulation of some compounds, whereas for others, no significant environmental effect occurred. However, for a few compounds significant family x environment interactions were found. These results suggest that P. c. latifolia secondary chemistry is under strong genetic control, but the effects depend on the individual compounds and whether or not they are expressed constitutively or following induction. PMID:21845434

  2. Genetic variation of lodgepole pine, Pinus contorta var. latifolia, chemical and physical defenses that affect mountain pine beetle, Dendroctonus ponderosae, attack and tree mortality.

    PubMed

    Ott, Daniel S; Yanchuk, Alvin D; Huber, Dezene P W; Wallin, Kimberly F

    2011-09-01

    Plant secondary chemistry is determined by both genetic and environmental factors, and while large intraspecific variation in secondary chemistry has been reported frequently, the levels of genetic variation of many secondary metabolites in forest trees in the context of potential resistance against pests have been rarely investigated. We examined the effect of tree genotype and environment/site on the variation in defensive secondary chemistry of lodgepole pine, Pinus contorta var. latifolia, against the fungus, Grosmannia clavigera (formerly known as Ophiostoma clavigerum), associated with the mountain pine beetle, Dendroctonus ponderosae. Terpenoids were analyzed in phloem samples from 887, 20-yr-old trees originating from 45 half-sibling families planted at two sites. Samples were collected both pre- and post-inoculation with G. clavigera. Significant variation in constitutive and induced terpenoid compounds was attributed to differences among families. The response to the challenge inoculation with G. clavigera was strong for some individual compounds, but primarily for monoterpenoids. Environment (site) also had a significant effect on the accumulation of some compounds, whereas for others, no significant environmental effect occurred. However, for a few compounds significant family x environment interactions were found. These results suggest that P. c. latifolia secondary chemistry is under strong genetic control, but the effects depend on the individual compounds and whether or not they are expressed constitutively or following induction.

  3. Hydroxycinnamic acid degradation, a broadly conserved trait, protects Ralstonia solanacearum from chemical plant defenses and contributes to root colonization and virulence

    PubMed Central

    Lowe, Tiffany M.; Ailloud, Florent; Allen, Caitilyn

    2014-01-01

    Plants produce hydroxycinnamic acid defense compounds (HCAs) to combat pathogens, such as the bacterium Ralstonia solanacearum. We showed that an HCA degradation pathway is genetically and functionally conserved across diverse R. solanacearum strains. Further, a Δfcs (feruloyl-CoA synthetase) mutant that cannot degrade HCAs was less virulent on tomato plants. To understand the role of HCA degradation in bacterial wilt disease, we tested the following hypotheses: HCA degradation helps the pathogen (1) grow, as a carbon source; (2) spread, by reducing physical barriers HCA-derived; and (3) survive plant antimicrobial compounds. Although HCA degradation enabled R. solanacearum growth on HCAs in vitro, HCA degradation was dispensable for growth in xylem sap and root exudate, suggesting that HCAs are not significant carbon sources in planta. Acetyl-bromide quantification of lignin demonstrated that R. solanacearum infections did not affect the gross quantity or distribution of stem lignin. However, the Δfcs mutant was significantly more susceptible to inhibition by two HCAs: caffeate and p-coumarate. Finally, plant colonization assays suggested that HCA degradation facilitates early stages of infection and root colonization. Together, these results indicated that ability to degrade HCAs contributes to bacterial wilt virulence by facilitating root entry and by protecting the pathogen from HCA toxicity. PMID:25423265

  4. Hydroxycinnamic Acid Degradation, a Broadly Conserved Trait, Protects Ralstonia solanacearum from Chemical Plant Defenses and Contributes to Root Colonization and Virulence.

    PubMed

    Lowe, Tiffany M; Ailloud, Florent; Allen, Caitilyn

    2015-03-01

    Plants produce hydroxycinnamic acid (HCA) defense compounds to combat pathogens, such as the bacterium Ralstonia solanacearum. We showed that an HCA degradation pathway is genetically and functionally conserved across diverse R. solanacearum strains. Further, a feruloyl-CoA synthetase (Δfcs) mutant that cannot degrade HCA was less virulent on tomato plants. To understand the role of HCA degradation in bacterial wilt disease, we tested the following hypotheses: HCA degradation helps the pathogen i) grow, as a carbon source; ii) spread, by reducing HCA-derived physical barriers; and iii) survive plant antimicrobial compounds. Although HCA degradation enabled R. solanacearum growth on HCA in vitro, HCA degradation was dispensable for growth in xylem sap and root exudate, suggesting that HCA are not significant carbon sources in planta. Acetyl-bromide quantification of lignin demonstrated that R. solanacearum infections did not affect the gross quantity or distribution of stem lignin. However, the Δfcs mutant was significantly more susceptible to inhibition by two HCA, namely, caffeate and p-coumarate. Finally, plant colonization assays suggested that HCA degradation facilitates early stages of infection and root colonization. Together, these results indicated that ability to degrade HCA contributes to bacterial wilt virulence by facilitating root entry and by protecting the pathogen from HCA toxicity.

  5. Radiological Defense. Textbook.

    ERIC Educational Resources Information Center

    Defense Civil Preparedness Agency (DOD), Washington, DC.

    This textbook has been prepared under the direction of the Defense Civil Preparedness Agency (DCPA) Staff College for use as a student reference manual in radiological defense (RADEF) courses. It provides much of the basic technical information necessary for a proper understanding of radiological defense and summarizes RADEF planning and expected…

  6. An Active Immune Defense with a Minimal CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats) RNA and without the Cas6 Protein*

    PubMed Central

    Maier, Lisa-Katharina; Stachler, Aris-Edda; Saunders, Sita J.; Backofen, Rolf; Marchfelder, Anita

    2015-01-01

    The prokaryotic immune system CRISPR-Cas (clustered regularly interspaced short palindromic repeats-CRISPR-associated) is a defense system that protects prokaryotes against foreign DNA. The short CRISPR RNAs (crRNAs) are central components of this immune system. In CRISPR-Cas systems type I and III, crRNAs are generated by the endonuclease Cas6. We developed a Cas6b-independent crRNA maturation pathway for the Haloferax type I-B system in vivo that expresses a functional crRNA, which we termed independently generated crRNA (icrRNA). The icrRNA is effective in triggering degradation of an invader plasmid carrying the matching protospacer sequence. The Cas6b-independent maturation of the icrRNA allowed mutation of the repeat sequence without interfering with signals important for Cas6b processing. We generated 23 variants of the icrRNA and analyzed them for activity in the interference reaction. icrRNAs with deletions or mutations of the 3′ handle are still active in triggering an interference reaction. The complete 3′ handle could be removed without loss of activity. However, manipulations of the 5′ handle mostly led to loss of interference activity. Furthermore, we could show that in the presence of an icrRNA a strain without Cas6b (Δcas6b) is still active in interference. PMID:25512373

  7. An active immune defense with a minimal CRISPR (clustered regularly interspaced short palindromic repeats) RNA and without the Cas6 protein.

    PubMed

    Maier, Lisa-Katharina; Stachler, Aris-Edda; Saunders, Sita J; Backofen, Rolf; Marchfelder, Anita

    2015-02-13

    The prokaryotic immune system CRISPR-Cas (clustered regularly interspaced short palindromic repeats-CRISPR-associated) is a defense system that protects prokaryotes against foreign DNA. The short CRISPR RNAs (crRNAs) are central components of this immune system. In CRISPR-Cas systems type I and III, crRNAs are generated by the endonuclease Cas6. We developed a Cas6b-independent crRNA maturation pathway for the Haloferax type I-B system in vivo that expresses a functional crRNA, which we termed independently generated crRNA (icrRNA). The icrRNA is effective in triggering degradation of an invader plasmid carrying the matching protospacer sequence. The Cas6b-independent maturation of the icrRNA allowed mutation of the repeat sequence without interfering with signals important for Cas6b processing. We generated 23 variants of the icrRNA and analyzed them for activity in the interference reaction. icrRNAs with deletions or mutations of the 3' handle are still active in triggering an interference reaction. The complete 3' handle could be removed without loss of activity. However, manipulations of the 5' handle mostly led to loss of interference activity. Furthermore, we could show that in the presence of an icrRNA a strain without Cas6b (Δcas6b) is still active in interference.

  8. An active immune defense with a minimal CRISPR (clustered regularly interspaced short palindromic repeats) RNA and without the Cas6 protein.

    PubMed

    Maier, Lisa-Katharina; Stachler, Aris-Edda; Saunders, Sita J; Backofen, Rolf; Marchfelder, Anita

    2015-02-13

    The prokaryotic immune system CRISPR-Cas (clustered regularly interspaced short palindromic repeats-CRISPR-associated) is a defense system that protects prokaryotes against foreign DNA. The short CRISPR RNAs (crRNAs) are central components of this immune system. In CRISPR-Cas systems type I and III, crRNAs are generated by the endonuclease Cas6. We developed a Cas6b-independent crRNA maturation pathway for the Haloferax type I-B system in vivo that expresses a functional crRNA, which we termed independently generated crRNA (icrRNA). The icrRNA is effective in triggering degradation of an invader plasmid carrying the matching protospacer sequence. The Cas6b-independent maturation of the icrRNA allowed mutation of the repeat sequence without interfering with signals important for Cas6b processing. We generated 23 variants of the icrRNA and analyzed them for activity in the interference reaction. icrRNAs with deletions or mutations of the 3' handle are still active in triggering an interference reaction. The complete 3' handle could be removed without loss of activity. However, manipulations of the 5' handle mostly led to loss of interference activity. Furthermore, we could show that in the presence of an icrRNA a strain without Cas6b (Δcas6b) is still active in interference. PMID:25512373

  9. Investment in defense and cost of predator-induced defense along a resource gradient.

    PubMed

    Steiner, Ulrich K

    2007-05-01

    An organism's investment in different traits to reduce predation is determined by the fitness benefit of the defense relative to the fitness costs associated with the allocation of time and resources to the defense. Inherent tradeoffs in time and resource allocation should result in differential investment in defense along a resource gradient, but competing models predict different patterns of investment. There are currently insufficient empirical data on changes in investment in defensive traits or their costs along resource gradients to differentiate between the competing allocation models. In this study, I exposed tadpoles to caged predators along a resource gradient in order to estimate investment in defense and costs of defense by assessing predator-induced plasticity. Induced defenses included increased tail depth, reduced feeding, and reduced swimming activity; costs associated with these defenses were reduced developmental rate, reduced growth, and reduced survival. At low resource availability, these costs predominately resulted in reduced survival, while at high resource availability the costs yielded a reduced developmental rate. Defensive traits responded strongly to predation risk, but did not respond to resource availability (with the exception of feeding activity), whereas traits construed as costs of defenses showed the opposite pattern. Therefore, defensive traits were highly sensitive to predation risk, while traits construed as costs of defense were highly sensitive to resource allocation tradeoffs. This difference in sensitivity between the two groups of traits may explain why the correlation between the expression of defensive traits and the expression of the associated defense costs was weak. Furthermore, my results indicate that genetic linkages and mechanistic integration of multiple defensive traits and their associated costs may constrain time and resource allocation in ways that are not addressed in existing models.

  10. Activation of Antioxidant Defenses in Whole Saliva by Psychosocial Stress Is More Manifested in Young Women than in Young Men

    PubMed Central

    Tsuber, Viktoriia; Kadamov, Yunus; Tarasenko, Lydia

    2014-01-01

    Psychosocial stress has been long known to have deleterious effects on health. Nevertheless, an exposure to moderate stressors enhances resilience and promotes health benefits. Male and female organisms differ in many aspects of health and disease. The aim of this study was to investigate antioxidant activity and oxidative damage in saliva in a psychosocial stress paradigm in men and women. Here, we show that an acute stressor of moderate strength augments antioxidant activity and decreases oxidative damage in whole saliva of young people. An examination stress caused a significant increase of catalase activity, accompanied by a decrease of levels of oxidized proteins. Levels of thiobarbituric acid-reacting substances did not increase at stress, indicating that lipid peroxidation was not activated. The stress-induced alterations were more manifested in young women compared to young men. Thus, antioxidant protective mechanisms are more activated by a moderate stressor in young women than in young men. PMID:25525800

  11. Activated carbons obtained from sewage sludge by chemical activation: gas-phase environmental applications.

    PubMed

    Boualem, T; Debab, A; Martínez de Yuso, A; Izquierdo, M T

    2014-07-01

    The objective of this study was to evaluate the adsorption capacity for toluene and SO2 of low cost activated carbons prepared from sewage sludge by chemical activation at different impregnation ratios. Samples were characterized by proximate and ultimate analyses, thermogravimetry, infrared spectroscopy and N2 adsorption. Because of the low carbon content of the raw material, the development of porosity in the activated carbons was mainly of a mesoporous nature, with surface areas lower than 300 m(2)/g. The study of gas-phase applications for activated carbons from sewage sludge was carried out using both an organic and an inorganic compound in order to screen for possible applications. Toluene adsorption capacity at saturation was around 280 mg/g, which is a good level of performance given the high ash content of the activated carbons. However, dynamic experiments at low toluene concentration presented diffusion problems resulting from low porosity development. SO2 adsorption capacity is associated with average micropore size, which can be controlled by the impregnation ratio used to prepare the activated carbons.

  12. Multiple animal studies for medical chemical defense program in soldier/patient decontamination and drug development. Final report, 1 June 1987-9 September 1988

    SciTech Connect

    Joiner, R.L.; Dill, S.; Hobson, W.; Keys, W.B.

    1989-11-01

    A task was initiated using a rabbit model to compare the effectiveness against chemical surety materiels (CSM) applied dermally, of candidate topical protectants against a reference. The reference was a mixture of polyethylene glycols and the CSM used were thickened soman, VX, and sulfur mustard. The purpose of the comparison was to eliminate those candidates that were not as effective as the reference. A total of 16 tests were performed to evaluate 6 candidate protectants.

  13. Trade-offs in antiherbivore defenses in Piper cenocladum: ant mutualists versus plant secondary metabolites.

    PubMed

    Dyer, L A; Dodson, C D; Beihoffer, J; Letourneau, D K

    2001-03-01

    Ant-plant mutualisms may provide indirect evidence for costs of antiherbivore defenses when plants demonstrate trade-offs between allocating resources and energy into ant attractants versus chemical defenses. We tested the hypothesis that ecological trade-offs in defenses are present in Piper cenocladum. This plant possesses two distinct defenses: food bodies that attract predatory ants that destroy herbivore eggs and amides that deter herbivores. Previous studies have demonstrated that the food bodies in P. cenocladum are an effective defense because the ants deter herbivory by specialist herbivores. Amides in other Piper species have been shown to have toxic qualities, but we tested the additional hypothesis that these amides have an actual defensive function in P. cenocladum. To test for ecological trade-offs between the two putative defenses, fragments of P. cenocladum were examined for the presence of amides both when the plant was producing food bodies and when it was not producing food bodies. Plants with active ant colonies had redundant defenses, producing food bodies and high levels of amides at the same time, but we detected a trade-off in that they had significantly lower levels of amides than did plants with no ants. To test for the defensive value of P. cenocladum amides, we used an ant bioassay and we examined herbivory results from previous experiments with plants that had variable levels of amides. These tests demonstrated that amides are deterrent to omnivorous ants, leaf cutting ants, and orthopterans. In contrast, the resident Pheidole bicornis ants are effective at deterring herbivory by specialist herbivores that oviposit eggs on the plant but not at deterring herbivory by nonresident omnivores. We concluded that although both amides and food body production appear to be costly, redundancy in defenses is necessary to avoid damage by a complex suit of herbivores.

  14. 75 FR 6386 - Pesticide Products; Registration Applications for a New Active Ingredient Chemical; Demiditraz

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-09

    ... register pesticide products containing active ingredients not included in any previously registered pesticide products. Pursuant to the provisions of section 3(c)(4) of the Federal Insecticide, Fungicide, and... AGENCY Pesticide Products; Registration Applications for a New Active Ingredient Chemical;...

  15. Correlations between neuron activity in the sensorimotor cortex of the right and left hemispheres in rabbits during a defensive dominant and "animal hypnosis".

    PubMed

    Bogdanov, A V; Galashina, A G; Karamysheva, N N

    2010-09-01

    A latent focus of excitation with a rhythmic nature (a defensive dominant focus) was created in the CNS of rabbits. The focus was formed by threshold electrocutaneous stimulation of the left forelimb using series of impulses consisting of 15-20 stimuli with interstimulus intervals of 2 sec. The linked activity of cells in the sensorimotor cortex of the right and left hemispheres was analyzed. When cross-correlation histograms of the spike activity of sensorimotor cortex neurons in the left hemisphere were constructed and analyzed in relation to spikes of high and intermediate amplitude recorded in the right hemisphere, the linked activity of 15% and 23% of neuron pairs, respectively, showed predominance of a rhythm equal or close to the stimulation rhythm used to form the dominant focus. When the appearance times of spikes from neurons in the sensorimotor cortex of the right hemisphere were analyzed in relation to spikes of high and intermediate amplitude recorded in the cortex of the left hemisphere, predominance of 2-sec rhythms was seen in the linked activity of only 3% and 10% of neuron pairs, respectively. After induction of "animal hypnosis," differences between the hemispheres in relation to this measure leveled out.

  16. Adsorption studies of methylene blue and phenol onto vetiver roots activated carbon prepared by chemical activation.

    PubMed

    Altenor, Sandro; Carene, Betty; Emmanuel, Evens; Lambert, Jacques; Ehrhardt, Jean-Jacques; Gaspard, Sarra

    2009-06-15

    Vetiver roots have been utilized for the preparation of activated carbon (AC) by chemical activation with different impregnation ratios of phosphoric acid, X(P) (gH(3)PO(4)/g precursor): 0.5:1; 1:1 and 1.5:1. Textural characterization, determined by nitrogen adsorption at 77K shows that mixed microporous and mesoporous structures activated carbons (ACs) with high surface area (>1000 m(2)/g) and high pore volume (up to 1.19 cm(3)/g) can be obtained. The surface chemical properties of these ACs were investigated by X-ray photoelectron spectroscopy (XPS) and Boehm titration. Their textural and chemical characteristics were compared to those of an AC sample obtained by steam activation of vetiver roots. Classical molecules used for characterizing liquid phase adsorption, phenol and methylene blue (MB), were used. Adsorption kinetics of MB and phenol have been studied using commonly used kinetic models, i.e., the pseudo-first-order model, the pseudo-second-order model, the intraparticle diffusion model and as well the fractal, BWS (Brouers, Weron and Sotolongo) kinetic equation. The correlation coefficients (R(2)) and the normalized standard deviation Deltaq (%) were determined showing globally, that the recently derived fractal kinetic equation could best describe the adsorption kinetics for the adsorbates tested here, indicating a complex adsorption mechanism. The experimental adsorption isotherms of these molecules on the activated carbon were as well analysed using four isotherms: the classical Freundlich, Langmuir, Redlich-Peterson equations, but as well the newly published deformed Weibull Brouers-Sotolongo isotherm. The results obtained from the application of the equations show that the best fits were achieved with the Brouers-Sotolongo equation and with the Redlich-Peterson equation. Influence of surface functional groups towards MB adsorption is as well studied using various ACs prepared from vetiver roots and sugar cane bagasse. Opposite effects governing MB

  17. LIMITED-USE CHEMICAL PROTECTIVE CLOTHING FOR EPA SUPERFUND ACTIVITIES

    EPA Science Inventory

    Because contractor field personnel complained about the poor durability and fit of limited-use chemical protective clothing (CPC) most commonly used at hazardous waste site operations, the U.S. Environmental Protection Agency (EPA) initiated a study to • characterize use of CPC...

  18. U.S. Army chemical demilitarization and remediation activity non-stockpile monitoring approach

    SciTech Connect

    Queen, J.; Miskelly, P.; Chatfield, M.J.

    1995-06-01

    In Section 176 of Public Law (PL) 102-484, the 1993 Defense Authorization Act, Congress directed the U.S. Army to submit a report identifying the locations, types, and quantities of non-stockpile chemical material (NSCM). As part of that report, published in the Survey and Analysis Report for the Non-Stockpile Chemical Material Program, five categories of NSCM were addressed: buried chemical warfare material (CWM); recovered chemical weapons- and miscellaneous CWM. To better define the scope of CWM burial sites, four separate types of sites were discussed-chemical agent identification set (CAIS) burials, small CWM burial sites with no explosives, small CWM burial sites with explosives, and large CWM burial sites (with and without explosives). A total of 215 potential CWM burial sites, distributed throughout 33 states, the U.S. Virgin Islands, and the District of Columbia, were identified. This article describes the rapid response system; CAIS characterization and disposal; monitoring during RRS operations; monitoring standards, and the non-stockpile monitoring program.

  19. Thermal stress in seven types of chemical defense ensembles during moderate exercise in hot environments. Final report, May 1991-July 1992

    SciTech Connect

    Bomalaski, S.H.; Hengst, R.; Constable, S.H.

    1993-08-01

    United States Air Force -(USAF) personnel must perform their duties in many operational environments, including those with the potential for contamination with toxic chemical warfare (CW) agents. This study evaluated the physiological response to thermal stress in subjects performing moderate work in current and prototype chemical protective garments including the Battle Dress Overgarment (BDO)+BDU, BDO without BDU, United Kingdom (UK) undercoverall+BDU, Gore-Tex rainsuit+PJ-7 undercoverall, Marine Light Fighter Suit (MLFS), CWU77P, PJ-7 alone, and the BDU alone. Experimental conditions were dry bulb temperature of 40 deg C (104 deg F), a wet bulb temperature of 270C (80.6 deg F), and a black globe temperature of 450C (113 deg F). Eleven subjects walked on a treadmill at 3 mph with a 5% grade incline until rectal temperature (Tre) rose 1.5 deg C (2.7 deg F) above the starting value. Heart rate, rectal and mean skin temperature, and body heat storage were monitored continuously. Sweat evaporation and production were determined from the differences between pre- and postexperiment clothed and nude weights. Significantly longer work times, lower heart rates, lower Tmsk, and lower heat storage, were seen in the group comprised of the BDU, MLFS, CWU-77P, and PJ-7 compared to the Gore-Tex with PJ-7, UK plus BD BDO+BDU, and BDO no BDU ensembles. Suits which resulted in shorter tolerance times also caused rates of sweat production and lower % sweat evaporation than the less physiologically burdensome suits. Chemical protective ensembles, Thermal stress, Clothing, Exercise.

  20. Chemically active organically doped sol-gel materials: enzymatic sensors, chemical sensors, and photoactive materials

    NASA Astrophysics Data System (ADS)

    Avnir, David; Braun, S.; Lev, Ovadia; Ottolenghi, M.

    1992-12-01

    Organically-doped porous sol-gel matrices of optical grade have evolved in recent years into a wide class of materials with diverse applications. We review recent progress made in our laboratories in three domains of applications: the trapping of enzymes with the consequent design of (e.g. glucose) sensors; the development of chemical sensors; and the design of photoactive material for (solar) light energy conversion.

  1. Effect of water pollutants and other chemicals upon ribonuclease activity in vitro

    SciTech Connect

    Christensen, G.M.; Olson, D.L.

    1981-12-01

    Ribonuclease was treated in vitro with 73 chemicals, many of which are environmental pollutants, including inorganic, organic, and metal-organic chemicals, pesticides and other biocides, alkyl and aryl industrial pollutants, and certain additional chemicals, to determine their effect upon enzyme activity. Palladium (II and IV) and gold (III) were the strongest inhibitors of RNase activity. Other strong inhibitors, in decreasing order of effect, were: sodium dodecyl sulfate, silver (I), EDTA, mercury (II), copper (II), thiram (fungicide), platinum (IV), malathion (pesticide), lead (II), and beryllium (II). Intermediate effects were found with other inorganic cations, many anions, and some other chemicals. A number of compounds of different chemical types caused no measureable effect. None of the chemicals tested caused a measureable activation of this enzyme.

  2. Genetic activity profiles in the testing and evaluation of chemical mixtures

    SciTech Connect

    Waters, M.D.; Claxton, L.D.; Stack, H.F.; Brady, A.L.; Graedel, T.E. )

    1990-01-01

    Some knowledge of the potential genetic activity of a complex environmental mixture may be gained from an assessment of the genetic activity of its component chemicals. The expanded Genetic Activity Profile (GAP) data base provides a computer-generated graphic representation of genetic bioassay data as a function of dose of the substance tested. In addition, the Atmospheric Chemical Compound (ACC) data-base contains information on chemical structures, properties, detection methods, and sources of chemicals found in ambient air. Using the combined data bases, the quantity of an individual chemical present within a mixture or fraction of a mixture may be related to the quantity (lowest effective dose, LED) of the chemical, by itself, required to demonstrate a positive response in one or more genetic bioassays. 19 references.

  3. Density-dependent adjustment of inducible defenses

    PubMed Central

    Tollrian, Ralph; Duggen, Sonja; Weiss, Linda C.; Laforsch, Christian; Kopp, Michael

    2015-01-01

    Predation is a major factor driving evolution, and organisms have evolved adaptations increasing their survival chances. However, most defenses incur trade-offs between benefits and costs. Many organisms save costs by employing inducible defenses as responses to fluctuating predation risk. The level of defense often increases with predator densities. However, individual predation risk should not only depend on predator density but also on the density of conspecifics. If the predator has a saturating functional response one would predict a negative correlation between prey density and individual predation risk and hence defense expression. Here, we tested this hypothesis using six model systems, covering a taxonomic range from protozoa to rotifers and crustaceans. In all six systems, we found that the level of defense expression increased with predator density but decreased with prey density. In one of our systems, i.e. in Daphnia, we further show that the response to prey density is triggered by a chemical cue released by conspecifics and congeners. Our results indicate that organisms adjust the degree of defense to the acute predation risk, rather than merely to predators’ densities. Our study suggests that density-dependent defense expression reflects accurate predation-risk assessment and is a general principle in many inducible-defense systems. PMID:26235428

  4. Evaluation of the vapor-protection capabilities of the jacket/trouser interface on the regulation ground-crew chemical defense ensemble. Interim report, 15 Nov-15 Dec 88

    SciTech Connect

    Scott, W.R.; Pointer, B.W.

    1990-12-01

    The ground-crew chemical defense ensemble (CDE) has deficiencies in its ability to prevent chemical warfare (CW) simulant vapors from leaking past the outer charcoal layer in the abdominal region when personnel wearing this CDE perform exercise in a simulant CW agent vapor. The purpose of this study was to determine the site and amount of vapor penetration. A charcoal-fabric cummerbund was used as an experimental tool to prevent vapor from leaking through the jacket/trouser interface. Test subjects, wearing the ground-crew CDE with and without cummerbund, performed exercises in a CW simulant vapor (methyl salicylate). While subjects were exposed to the simulant vapor, vapor concentrations were measured under the CDE jacket in the abdominal region. After removing the CDE in a vapor-free area, subjects entered sealed offgassing booths where simulant vapor levels were continuously measured. Subjects wearing a cummerbund had 80% lower abdominal vapor concentrations and 33% lower maximum offgassing booth concentrations than subjects that did not wear a cummerbund. The source of the vapor penetration is along the jacket/ trouser interface of the ground crew CDE.

  5. Investigation of the effect of laundering the ground crew chemical defense overgarment on toxic-free-area vapor transfer during shelter entry by initially contaminated personnel. Interim report, Oct 87-Jan 88

    SciTech Connect

    Simpson, R.E.

    1990-12-01

    A study by the U.S. Air Force School of Aerospace Medicine, Brooks AFB, Texas, has compared the shelter processing transfer of chemical warfare agent simulant vapor for subjects wearing unwashed and laundered ground-crew chemical defense overgarments. Twice laundered and four times laundered protective garments were included in the assessment. Test subjects, wearing the unwashed and laundered protective garments were initially sprayed with liquid simulant (methyl salicylate) to a target density of 5 g m-2. They were then sequentially processed into and through the USAFSAM Collective Protection Shelter (SCPS-2B) test facility. Immediately upon entry to the Toxic-Free Area, the subjects were confined in individual off gassing booths for 2 h while offgassed simulant vapor concentration in the booths was recorded. The resulting mean maximum vapor concentrations recorded in the booths for subjects who had worn unwashed and laundered overgarments prior to booth entry were not statistically different at the .05 significance level. However, the 4-times laundered garment subjects (3 out of 4 subjects) showed an average 40% increase in booth vapor concentration compared with subjects wearing unwashed garments.

  6. Evaluation of the vapor-protection capabilities of the M17 respirator/hood assembly on the USAF ground-crew chemical defense ensemble. Interim report, 21 March-2 June 1988

    SciTech Connect

    Scott, W.R.; Simpson, R.E.

    1989-10-01

    The hood used with the M17 respirator on the regulation United States Air Force (USAF) ground-crew chemical defense ensemble (CDE) may have deficiencies, both in construction and usage, in its ability to protect the neck from chemical agent vapors. The purpose of this study was to quantify vapor penetration under the hood skirt to the neck and measure the effect of this vapor penetration on vapor carry-through into the Toxic Free Area (TFA) of the Survivable Collective Protection Shelter Contamination Control Area (SCPS-2B CCA) facility at Brooks AFB, Texas. Test subjects, wearing the regulation ground-crew CDE, performed light exercises in a simulant vapor (methyl salicylate). Vapor concentrations were measured at the neck with Tenax tubes and in the SCPS-2B with sequential impingers. When the hood skirt was worn outside the CDE jacket, the standard configuration, the mean simulant vapor level at the neck was 29.6% of the outside vapor concentration. Placing the hood skirt underneath the CDE jacket resulted in an 87% decrease in the neck vapor concentrations and a 50% reduction in TFA vapor carry-through.

  7. Novel aspinolide production by Trichoderma arundinaceum with a potential role in Botrytis cinerea antagonistic activity and plant defense priming

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Harzianum A (HA), a trichothecene produced by Trichoderma arundinaceum, has recently been described to have antagonistic activity against fungal plant pathogens and to induce plant defence genes. In the present work, we have shown that a tri5 genedisrupted mutant that lacks HA production overproduce...

  8. Chemical modification of capuramycins to enhance antibacterial activity

    PubMed Central

    Bogatcheva, Elena; Dubuisson, Tia; Protopopova, Marina; Einck, Leo; Nacy, Carol A.; Reddy, Venkata M.

    2011-01-01

    Objectives To extend capuramycin spectrum of activity beyond mycobacteria and improve intracellular drug activity. Methods Three capuramycin analogues (SQ997, SQ922 and SQ641) were conjugated with different natural and unnatural amino acids or decanoic acid (DEC) through an ester bond at one or more available hydroxyl groups. In vitro activity of the modified compounds was determined against Mycobacterium spp. and representative Gram-positive and Gram-negative bacteria. Intracellular activity was evaluated in J774A.1 mouse macrophages infected with Mycobacterium tuberculosis (H37Rv). Results Acylation of SQ997 and SQ641 with amino undecanoic acid (AUA) improved in vitro activity against most of the bacteria tested. Conjugation of SQ922 with DEC, but not AUA, improved its activity against Gram-positive bacteria. In the presence of efflux pump inhibitor phenylalanine arginine β-naphthyl amide, MICs of SQ997-AUA, SQ641-AUA and SQ922-DEC compounds improved even further against drug-susceptible and drug-resistant Staphylococcus aureus. In Gram-negative bacteria, EDTA-mediated permeabilization caused 4- to 16-fold enhancement of the activity of AUA-conjugated SQ997, SQ922 and SQ641. Conjugation of all three capuramycin analogues with AUA improved intracellular killing of H37Rv in murine macrophages. Conclusions Conjugation of capuramycin analogues with AUA or DEC enhanced in vitro activity, extended the spectrum of activity in Gram-positive bacteria and increased intracellular activity against H37Rv. PMID:21186194

  9. Star wars and strategic defense initiatives: work activity and health symptoms of unionized bank tellers during work reorganization.

    PubMed

    Seifert, A M; Messing, K; Dumais, L

    1997-01-01

    Work activity and health symptoms of bank tellers whose work was undergoing reorganization were examined during a university-union study of the health effects of work in women's traditional jobs. Data were gathered through collective and individual interviews, analysis of work activity, and a questionnaire administered to 305 tellers. Employees worked in a standing posture over 80 percent of the time. More than two-thirds frequently suffered pain in back, legs, and feet. The average teller had been involved in 3.7 robberies as a direct victim and six as a witness. Work required feats of memory and concentration. In order to meet job demands, tellers engaged in supportive activities and teamwork. The introduction of individualized objectives threatened the employees' ability to collaborate and induced distress. More than twice as many tellers as other female workers in Québec experience psychological distress (Ilfeld scale), related to: robbery during the past two years (odds ratio = 1.7; confidence interval = 1.0-2.9); difficult relations with superiors (O.R. = 2.6; C.I. = 1.3-5.3); and full-time work (O.R. = 2.3; C.I. = 1.3-3.9). Diverse methods enriched the analysis, and union participation allowed the proposal of concrete correction measures.

  10. Star wars and strategic defense initiatives: work activity and health symptoms of unionized bank tellers during work reorganization.

    PubMed

    Seifert, A M; Messing, K; Dumais, L

    1997-01-01

    Work activity and health symptoms of bank tellers whose work was undergoing reorganization were examined during a university-union study of the health effects of work in women's traditional jobs. Data were gathered through collective and individual interviews, analysis of work activity, and a questionnaire administered to 305 tellers. Employees worked in a standing posture over 80 percent of the time. More than two-thirds frequently suffered pain in back, legs, and feet. The average teller had been involved in 3.7 robberies as a direct victim and six as a witness. Work required feats of memory and concentration. In order to meet job demands, tellers engaged in supportive activities and teamwork. The introduction of individualized objectives threatened the employees' ability to collaborate and induced distress. More than twice as many tellers as other female workers in Québec experience psychological distress (Ilfeld scale), related to: robbery during the past two years (odds ratio = 1.7; confidence interval = 1.0-2.9); difficult relations with superiors (O.R. = 2.6; C.I. = 1.3-5.3); and full-time work (O.R. = 2.3; C.I. = 1.3-3.9). Diverse methods enriched the analysis, and union participation allowed the proposal of concrete correction measures. PMID:9285277

  11. An acoustic microscopy technique reveals hidden morphological defenses in Daphnia.

    PubMed

    Laforsch, Christian; Ngwa, Wilfred; Grill, Wolfgang; Tollrian, Ralph

    2004-11-01

    Inducible defenses are common strategies for coping with the selective force of predation in heterogeneous environments. In recent years the conspicuous and often dramatic morphological plasticity of several waterflea species of the genus Daphnia have been found to be inducible defenses activated by chemical cues released by predators. However, the exact defensive mechanisms remained mysterious. Because even some minute morphological alterations proved to be protective against predatory invertebrates, it has been suggested that the visible morphological changes are only the tip of the iceberg of the entire protective mechanisms. Here we applied a method of ultrasonic microscopy with vector contrast at 1.2 GHz to probe hidden morphological defenses. We found that induction with predator kairomones increases the stability of the carapace in two Daphnia species up to 350%. This morphological plasticity provides a major advantage for the induced morphs during predation because predatory invertebrates need to crush or puncture the carapace of their prey to consume them. Our ultrastructural analyses revealed that the internal architecture of the carapace ensures maximal rigidity with minimal material investment. Our results uncover hidden morphological plasticity and suggest a reconsideration of former classification systems in defended and undefended genotypes in Daphnia and possibly in other prey organisms as well.

  12. An acoustic microscopy technique reveals hidden morphological defenses in Daphnia

    PubMed Central

    Laforsch, Christian; Ngwa, Wilfred; Grill, Wolfgang; Tollrian, Ralph

    2004-01-01

    Inducible defenses are common strategies for coping with the selective force of predation in heterogeneous environments. In recent years the conspicuous and often dramatic morphological plasticity of several waterflea species of the genus Daphnia have been found to be inducible defenses activated by chemical cues released by predators. However, the exact defensive mechanisms remained mysterious. Because even some minute morphological alterations proved to be protective against predatory invertebrates, it has been suggested that the visible morphological changes are only the tip of the iceberg of the entire protective mechanisms. Here we applied a method of ultrasonic microscopy with vector contrast at 1.2 GHz to probe hidden morphological defenses. We found that induction with predator kairomones increases the stability of the carapace in two Daphnia species up to 350%. This morphological plasticity provides a major advantage for the induced morphs during predation because predatory invertebrates need to crush or puncture the carapace of their prey to consume them. Our ultrastructural analyses revealed that the internal architecture of the carapace ensures maximal rigidity with minimal material investment. Our results uncover hidden morphological plasticity and suggest a reconsideration of former classification systems in defended and undefended genotypes in Daphnia and possibly in other prey organisms as well. PMID:15520396

  13. Activated persulfate for organic chemical degradation: A review.

    PubMed

    Matzek, Laura W; Carter, Kimberly E

    2016-05-01

    Activated persulfate reactions have widespread application for groundwater and environmental remediation, as many of these reactions involve destruction of environmental contaminants. Within the last five years, knowledge of activated persulfate degradation reactions has grown to include novel means of activating persulfate for enhanced removal of organic species. These current studies cover a long list of organic analytes, including pharmaceuticals, pesticides, halogenated compounds and dyes. An extensive review of recently published experimental parameters and results for the destruction of organic compounds via activated persulfate is presented. Focus is placed on emerging methodologies and manipulation of traditional activation techniques. Knowledge gaps are identified and discussed, as despite the number of publications on this subject, more broad-reaching guidelines are needed for optimizing applications of activated persulfate in water treatment.

  14. Two systems and defenses.

    PubMed

    Novick, Jack; Novick, Kerry Kelly

    2013-02-01

    The authors suggest that Freud's concept of defense differentiated psychoanalysis from other medical and psychological theories of personality development and functioning then and now. Reclaiming the concept's centrality and linking it with interdisciplinary research findings, they illustrate their extension of defense into a two-system model of self-protection and self-regulation with a clinical example. The authors suggest that the two-system model allows for the reintegration of defense into a multidimensional psychoanalytic theory and multimodal therapeutic technique.

  15. Oncogene activation in spontaneous and chemically induced rodent tumors: implications for risk analysis

    SciTech Connect

    Reynolds, S.H.; Stowers, S.J.; Patterson, R.M.; Maronpot, R.R.; Anderson, M.W.

    1988-06-01

    The validity of rodent tumor end points in assessing the potential hazards of chemical exposure to humans is a somewhat controversial but very important issue since most chemicals are classified as potentially hazardous to humans on the basis of long-term carcinogenesis studies in rodents. The ability to distinguish between genotoxic, cytotoxic, or receptor-mediated promotion effects of chemical treatment would aid in the interpretation of rodent carcinogenesis data. Activated oncogenes in spontaneously occurring and chemically induced rodent tumors were examined and compared as one approach to determine the mechanism by which chemical treatment caused an increased incidence of rodent tumors. Different patterns of activated oncogenes were found not only in spontaneous versus chemically induced mouse liver tumors but also in a variety of spontaneous rat tumors versus chemically induced rat lung tumors. In the absence of cytotoxic effects, it could be argued that the chemicals in question activated protooncogenes by a direct genotoxic mechanism. These results provided a basis for the analysis of activated oncogenes in spontaneous and chemically induced rodent tumors to provide information at a molecular level to aid in the extrapolation of rodent carcinogenesis data to human risk assessment.

  16. 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