Science.gov

Sample records for air defence artillery

  1. The development of a ram air decelerator for the recovery of artillery shells

    NASA Astrophysics Data System (ADS)

    Behr, Vance L.; Cole, J. Kenneth; Croll, Robert H.

    A ram air decelerator (RAD) was investigated as a possible replacement for the present parachute recovery system for atomic artillery shells that are periodically tested by artillery firings. Tests included spin tests in a high altitude chamber, proof-of-concept tests on a truck towing rig, nonspinning airdrop tests and artillery fired projectile tests. A RAD is typically constructed of a top fabric panel and a bottom fabric panel that are fastened together along their outer edges to form a closed container. To improve the filament loading efficiency of the RAD design, a modification to a four-lobe design was made that offered a larger projected area of inflated fabric to the flow than did the original three-lobe design, thus giving the four-lobe design more drag for the same tip radius than the three-lobe design.

  2. Geologic and hydrologic data for the municipal solid waste landfill facility, U.S. Army Air Defense Artillery Center and Fort Bliss, El Paso County, Texas

    USGS Publications Warehouse

    Abeyta, Cynthia G.; Frenzel, P.F.

    1999-01-01

    Geologic and hydrologic data for the Municipal Solid Waste Landfill Facility on the U.S. Army Air Defense Artillery Center and Fort Bliss in El Paso County, Texas, were collected by the U.S. Geological Survey in cooperation with the U.S. Department of the Army. The 106.03-acre landfill has been in operation since January 1974. The landfill contains household refuse, Post solid wastes, bulky items, grass and tree trimmings from family housing, refuse from litter cans, construction debris, classified waste (dry), dead animals, asbestos, and empty oil cans. The depth of the filled areas is about 30 feet and the cover, consisting of locally derived material, is 2 to 3 feet thick. Geologic and hydrologic data were collected at or adjacent to the landfill during (1) drilling of 10 30- to 31-foot boreholes that were completed with gas-monitoring probes, (2) drilling of a 59-foot borehole, (3) drilling of a 355-foot borehole that was completed as a ground-water monitoring well, and (4) in situ measurements made on the landfill cover. After completion, the gas- monitoring probes were monitored on a quarterly basis (1 year total) for gases generated by the landfill. Water samples were collected from the ground-water monitoring well for chemical analysis. Data collection is divided into two elements: geologic data and hydrologic data. Geologic data include lithologic descriptions of cores and cuttings, geophysical logs, soil- gas and ambient-air analyses, and chemical analyses of soil. Hydrologic data include physical properties, total organic carbon, and pH of soil and sediment samples; soil-water chloride and soil-moisture analyses; physical properties of the landfill cover; measurements of depth to ground water; and ground-water chemical analyses. Interpretation of data is not included in this report.

  3. Hydrogeology and ground-water quality of the Chromic Acid Pit site, US Army Air Defense Artillery Center and Fort Bliss, El Paso, Texas

    USGS Publications Warehouse

    Abeyta, Cynthia G.; Thomas, C.L.

    1996-01-01

    The Chromic Acid Pit site is an inactive waste disposal site that is regulated by the Resource Conservation and Recovery Act of 1976. The 2.2-cubic-yard cement-lined pit was operated from 1980 to 1983 by a contractor to the U.S. Army Air Defense Artillery Center and Fort Bliss. The pit, located on the Fort Bliss military reservation, in El Paso, Texas, was used for disposal and evaporation of chromic acid waste generated from chrome plating operations. The site was certified closed in 1989 and the Texas Natural Resources Conservation Commission issued Permit Number HW-50296 (U.S. Environmental Protection Agency Permit Number TX4213720101), which approved and implemented post-closure care for the Chromic Acid Pit site. In accordance with an approved post-closure plan, the U.S. Geological Survey is cooperating with the U.S. Army in evaluating hydrogeologic conditions and ground- water quality at the site. One upgradient and two downgradient ground-water monitoring wells were installed adjacent to the chromic acid pit by a private contractor. Quarterly ground-water sampling of these wells by the U.S. Geological Survey began in December 1993. The Chromic Acid Pit site is situated in the Hueco Bolson intermontane valley. The Hueco Bolson is a primary source of ground water in the El Paso area. City of El Paso and U.S. Army water-supply wells are located on all sides of the study area and are completed 600 to more than 1,200 feet below land surface. The ground-water level in the area of the Chromic Acid Pit site has declined about 25 feet from 1982 to 1993. Depth to water at the Chromic Acid Pit site in September 1994 was about 284 feet below land surface; ground-water flow is to the southeast. Ground-water samples collected from monitoring wells at the Chromic Acid Pit site contained dissolved-solids concentrations of 442 to 564 milligrams per liter. Nitrate as nitrogen concentrations ranged from 2.1 to 2.7 milligrams per liter; nitrite plus nitrate as nitrogen

  4. Model input and output files for the simulation of time of arrival of landfill leachate at the water table, Municipal Solid Waste Landfill Facility, U.S. Army Air Defense Artillery Center and Fort Bliss, El Paso County, Texas

    USGS Publications Warehouse

    Abeyta, Cynthia G.; Frenzel, Peter F.

    1999-01-01

    This report contains listings of model input and output files for the simulation of the time of arrival of landfill leachate at the water table from the Municipal Solid Waste Landfill Facility (MSWLF), about 10 miles northeast of downtown El Paso, Texas. This simulation was done by the U.S. Geological Survey in cooperation with the U.S. Department of the Army, U.S. Army Air Defense Artillery Center and Fort Bliss, El Paso, Texas. The U.S. Environmental Protection Agency-developed Hydrologic Evaluation of Landfill Performance (HELP) and Multimedia Exposure Assessment (MULTIMED) computer models were used to simulate the production of leachate by a landfill and transport of landfill leachate to the water table. Model input data files used with and output files generated by the HELP and MULTIMED models are provided in ASCII format on a 3.5-inch 1.44-megabyte IBM-PC compatible floppy disk.

  5. Geohydrologic site characterization of the municipal solid waste landfill facility, US Army Air Defense Artillery Center and Fort Bliss, El Paso County, Texas

    USGS Publications Warehouse

    Abeyta, Cynthia G.

    1996-01-01

    Geohydrologic conditions of the Municipal Solid Waste Landfill Facility (MSWLF) on the U.S. Army Air Defense Artillery Center and Fort Bliss, El Paso County, Texas, were evaluated by the U.S. Geological Survey in cooperation with the U.S. Army. The 106.03-acre MSWLF has been in operation since January 1974. The landfill contains household refuse, Post solid wastes, bulky items, grass and tree trimmings from family housing, refuse from litter cans, construction debris, classified waste (dry), dead animals, asbestos, and empty oil cans. The MSWLF, located about 1,200 feet east of the nearest occupied structure, is estimated to receive an average of approximately 56 tons of municipal solid waste per day and, at a fill rate of 1-4 acres per year, is expected to reach its capacity by the year 2004. The MSWLF is located in the Hueco Bolson, 4 miles east of the Franklin Mountains. Elevations at the MSWLF range from 3,907 to 3,937 feet above sea level. The climate at the MSWLF and vicinity is arid continental, characterized by an abundance of sunny days, high summer temperatures, relatively cool winters typical of arid areas, scanty rainfall, and very low humidity throughout the year. Average annual temperature near the MSWLF and vicinity is 63.3 degrees Fahrenheit and annual precipitation is 7.8 inches. Potential evaporation in the El Paso area was estimated to be 65 inches per year. Soils at and adjacent to the MSWLF are nearly level to gently sloping, have a fine sandy loam subsoil, and are moderately deep over caliche. The MSWLF is underlain by Hueco Bolson deposits of Tertiary age and typically are composed of unconsolidated to slightly consolidated interbedded sands, clay, silt, gravel, and caliche. Individual beds are not well defined and range in thickness from a fraction of an inch to about 100 feet. The primary source of ground water in the MSWLF area is in the deposits of the Hueco Bolson. A relatively thick vadose zone of approximately 300 feet overlies the

  6. Premature detonation problem. [Artillery shells

    SciTech Connect

    Pimbley, G.H.; Marshall, E.F.

    1980-05-01

    Determining how cavities or voids in the explosive loads of artillery shells cause in-bore premature detonations is important to military authorities. Though answers continue to be elusive, in detailing recent studies of the problem at LASL, some traditional approaches were examined and a new direction of investigation is suggested. The aquarium experiment and the pipe test were devised at LASL to model the events taking place in a base gap, or in an internal cavity, in the load of an accelerating artillery shell. Numerical simulation was used to assess the data from these experiments. Both the experimental and the numerical simulation phases of the project are described. The commonly accepted gas compression, thermal ignition mechanism is not consistent with the results of this study. The dominant mechanism or mechanisms have not been identified.

  7. Geohydrology of the unsaturated zone and simulated time of arrival of landfill leachate at the water table, municipal solid waste landfill facility, US Army Air Defense Artillery Center and Fort Bliss, El Paso County, Texas

    USGS Publications Warehouse

    Frenzel, Peter F.; Abeyta, Cynthia G.

    1999-01-01

    The U.S. Air Defense Artillery Center and Fort Bliss Municipal Solid Waste Landfill Facility (MSWLF) is located about 10 miles northeast of downtown El Paso, Texas. The landfill is built on the Hueco Bolson, a deposit that yields water to five public-supply wells within 1.1 miles of the landfill boundary on all sides. The bolson deposits consist of lenses and mixtures of sand, clay, silt, gravel, and caliche. The unsaturated zone at the landfill is about 300 feet thick. The Hydrologic Evaluation of Landfill Performance (HELP) and the Multimedia Exposure Assessment Model for Evaluating the Land Disposal of Wastes (MULTIMED) computer models were used to simulate the time of first arrival of landfill leachate at the water table. Site-specific data were collected for model input. At five sites on the landfill cover, hydraulic conductivity was measured by an in situ method; in addition, laboratory values were obtained for porosity, moisture content at field capacity, and moisture content at wilting point. Twenty-seven sediment samples were collected from two adjacent boreholes drilled near the southwest corner of the landfill. Of these, 23 samples were assumed to represent the unsaturated zone beneath the landfill. The core samples were analyzed in the laboratory for various characteristics required for the HELP and MULTIMED models: initial moisture content, dry bulk density, porosity, saturated hydraulic conductivity, moisture retention percentages at various suction values, total organic carbon, and pH. Parameters were calculated for the van Genuchten and Brooks-Corey equations that relate hydraulic conductivity to saturation. A reported recharge value of 0.008 inch per year was estimated on the basis of soil- water chloride concentration. The HELP model was implemented using input values that were based mostly on site-specific data or assumed in a conservative manner. Exceptions were the default values used for waste characteristics. Flow through the landfill was

  8. Ground-water quality, water year 1995, and statistical analysis of ground-water-quality data, water years 1994-95, at the Chromic Acid Pit site, US Army Air Defense Artillery Center and Fort Bliss, El Paso, Texas

    USGS Publications Warehouse

    Abeyta, Cynthia G.; Roybal, R.G.

    1996-01-01

    The Chromic Acid Pit site is an inactive waste disposal site that is regulated by the Resource Conservation and Recovery Act of 1976. The 2.2-cubic-yard cement-lined pit was operated from 1980 to 1983 by a contractor to the U.S. Army Air Defense Artillery Center and Fort Bliss. The pit, located on the Fort Bliss military reservation in El Paso, Texas, was used for disposal and evaporation of chromic acid waste generated from chrome plating operations. The site was closed in 1989, and the Texas Natural Resources Conservation Commission issued permit number HW-50296 (U.S. Environmental Protection Agency number TX4213720101), which approved and implemented post-closure care for the Chromic Acid Pit site. In accordance with an approved post-closure plan, the U.S. Geological Survey is cooperating with the U.S. Army in monitoring and evaluating ground-water quality at the site. One upgradient ground-water monitoring well (MW1) and two downgradient ground-water monitoring wells (MW2 and MW3), installed adjacent to the chromic acid pit, are monitored on a quarterly basis. Ground-water sampling of these wells by the U.S. Geological Survey began in December 1993. The ground-water level, measured in a production well located approximately 1,700 feet southeast of the Chromic Acid Pit site, has declined about 29.43 feet from 1982 to 1995. Depth to water at the Chromic Acid Pit site in September 1995 was 284.2 to 286.5 feet below land surface; ground-water flow at the water table is assumed to be toward the southeast. Ground-water samples collected from monitoring wells at the Chromic Acid Pit site during water year 1995 contained dissolved- solids concentrations of 481 to 516 milligrams per liter. Total chromium concentrations detected above the laboratory reporting limit ranged from 0.0061 to 0.030 milligram per liter; dissolved chromium concentrations ranged from 0.0040 to 0.010 milligram per liter. Nitrate as nitrogen concentrations ranged from 2.1 to 2.8 milligrams per

  9. Future's operation areas: new-generation suppression enemy air defence (SEAD) elements

    NASA Astrophysics Data System (ADS)

    Hazinedar, Ä.°lker

    2015-05-01

    Since air vehicles took place in the theater of operations, they have become the indispensable elements and the strongest attack power of armed forces. In the following period, with technological development, supersonic aircrafts took place in the operation area and this increased effectiveness of air vehicles much more. Air forces have used these aircrafts during important missions like strategic attack and air defense operations. On the other hand, decision makers understood that it was not feasible to intercept fighter aircrafts by executing combat air patrol flight missions. Since there is not enough reaction time to intercept the high speed aircrafts, ground stationed Surface to Air Missiles (SAM) system requirement has emerged. Therefore, SAM systems took place in the operation scene as well. Due to the fact that SAM systems emerged against the attack power, the attack aircrafts are to keep away from the fire of the ground stationed SAM systems. Hence, the requirement of Suppression Enemy Air Defense (SEAD) arose. SEAD elements take under suppression the radar of the SAM systems. In this way, attack aircrafts are able to attack without the risk of SAM systems. The purpose of this study is to find new methods or concepts in order to protect friendly attack aircrafts against ground based surface to air missiles' fires. Modernization of SAM systems and new generation SAM system producing activities have proceeded with positive acceleration. So, current SEAD elements and concepts are not able to cover the requirements due to the increased SAM system ranges. According to the concepts, SEAD weapons` ranges must be longer than the SAM weapons' ranges to protect friendly aircrafts. In this study, new concept was offered to overcome the deficiencies of current SEAD concept. The elements of new concepts were put forward. Classic SEAD concept and new generation concepts were assessed by using SWOT analysis technique. As a result, this study has revealed that, air forces

  10. Multi radar tracking and multi sensor tracking in air defence systems

    NASA Astrophysics Data System (ADS)

    Berle, F. J.

    1983-10-01

    The netting of radars and the integration of other complementary sensors provide advantages with respect to system survivability and achieve a better quality air picture because of the resulting higher data rate. The paper describes an MST concept resulting from an extension of an operational MRT system and presents the results of a computer evaluation of the concept, emphasizing the processing of data from passive sensors and radars operating in passive mode. Three examples of different target density and number indicate the difficulties of processing sensor data in a jamming situation. Several possibilities of improvements are indicated.

  11. Artillery localization using networked wireless ground sensors

    NASA Astrophysics Data System (ADS)

    Swanson, David C.

    2002-08-01

    This paper presents the results of an installation of four acoustic/seismic ground sensors built using COTS computers and networking gear and operating on a continuous basis at Yuma Proving Grounds, Arizona. A description of the design can be found as well, which is essentially a Windows 2000 PC with 24-bit data acquisition, GPS timing, and environmental sensors for wind and temperature. A 4-element square acoustic array 1.8m on a side can be used to detect the time and angle of arrival of the muzzle blast and the impact explosion. A 3-component geophone allows the seismic wave direction to be estimated. The 8th channel of the 24-bit data acquisition system has a 1-pulse-per-second time signal from the GPS. This allows acoustic/seismic 'snapshots' to be coherently related from multiple disconnected ground sensor nodes. COTS 2.4 GHz frequency hopping radios (802.11 standard) are used with either omni or yagi antennas depending on the location on the range. Localization of the artillery or impact can be done by using the time and angle of arrival of the waves at 2 or more ground sensor locations. However, this straightforward analysis can be significantly complicated by weather and wind noise and is also the subject of another research contract. This work will present a general description of the COTS ground sensor installation, show example data autonomously collected including agent-based atmospheric data, and share some of the lessons learned from operating a Windows 2000 based system continuously outdoors.

  12. Field Artillery Ammunition Processing System (FAAPS) concept evaluation study

    SciTech Connect

    Kring, C.T.; Babcock, S.M.; Watkin, D.C.; Oliver, R.P.

    1992-06-01

    The Field Artillery Ammunition Processing System (FAAPS) is an initiative to introduce a palletized load system (PLS) that is transportable with an automated ammunition processing and storage system for use on the battlefield. System proponents have targeted a 20% increase in the ammunition processing rate over the current operation while simultaneously reducing the total number of assigned field artillery battalion personnel by 30. The overall objective of the FAAPS Project is the development and demonstration of an improved process to accomplish these goals. The initial phase of the FAAPS Project and the subject of this study is the FAAPS concept evaluation. The concept evaluation consists of (1) identifying assumptions and requirements, (2) documenting the process flow, (3) identifying and evaluating technologies available to accomplish the necessary ammunition processing and storage operations, and (4) presenting alternative concepts with associated costs, processing rates, and manpower requirements for accomplishing the operation. This study provides insight into the achievability of the desired objectives.

  13. Advances in digital memory telemeters for artillery projectiles

    NASA Astrophysics Data System (ADS)

    Szabo, L. R.; Osborne, W. I.

    The purpose of this paper is to review the progress currently being made in the semiconductor field and how these recent advances can be utilized in digital memory telemeters for gathering data from various artillery projectiles. Topics to be presented include: basic design considerations, high-g packaging techniques, and the high-g hardening of critical electronic components. In addition, a prototype memory telemeter, which is under development for ARDC's 155mm Ballistic Simulator, and the firing data it has recorded to date are discussed. Finally, a look at future advances in IC technology and its impact on digital memory telemeters is presented.

  14. A serious skin sulfur mustard burn from an artillery shell.

    PubMed

    Ruhl, C M; Park, S J; Danisa, O; Morgan, R F; Papirmeister, B; Sidell, F R; Edlich, R F; Anthony, L S; Himel, H N

    1994-01-01

    Despite the Geneva Protocol of 1925 and the Paris Conference on Prohibition of Chemical Weapons in 1989, sulfur mustard and other chemical weapons continue to pose a hazard to both civilians and soldiers. The presence of artillery shells containing sulfur mustard, both in waters where these shells were dumped and in old battlefields, presents a problem in times of peace, especially for those who collect wartime memorabilia. Past literature has reported several hundred incidents involving fishermen who inadvertently pulled leaking shells aboard their fishing vessels, thereby exposing themselves to the vesicant chemical. Other literature reports exposure to children who found the chemical shells in old battlefields. The purpose of this article is to report the first case of a serious sulfur mustard burn that occurred after removing the detonator from an old artillery shell in a historic battle field near Verdun, France. The circumstances surrounding the injury, the diagnosis and management of injuries secondary to sulfur mustard, and the long-term consequences to the patient are presented and discussed. Although skin grafting has been used in the management of other chemical burn injuries, this report is the first to describe the need for split-thickness skin grafts in the management of a patient with sulfur mustard burns.

  15. Manganese Deposits in the Artillery Mountains Region, Mohave County, Arizona

    USGS Publications Warehouse

    Lasky, S.G.; Webber, B.N.

    1944-01-01

    The manganese deposits of the Artillery Mountains region lie within an area of about 25 square miles between the Artillery and Rawhide Mountains, on the west side of the Bill Williams River in west-central Arizona. The richest croppings are on the northeast side of this area, among the foothills of the Artillery Mountains. They are 6 to 10 miles from Alamo. The nearest shipping points are Congress, about 50 miles to the east, and Aguila, about 50 miles to the southeast. The principal manganese deposits are part of a sequence of alluvial fan and playa material, probably of early Pliocene age, which were laid down in a fault basin. They are overlain by later Pliocene (?) basalt flows and sediments and by Quaternary basalt and alluvium. The Pliocene (?) rocks are folded into a shallow composite S1ncline ttat occupies the valley between the Artillery and Rawhide Mountains, and the folded rocks along either side of the valley, together with the overlying Quaternary basalt, are broken by faults that have produced a group of horsts, grabens, and step-fault blocks. The manganiferous beds, lie at two zones, 750 to 1,000 feet apart stratigraphically, each of which is locally as much as 300 to 400 feet thick. The main, or upper, zone contains three kinds of ore - sandstone ore, clay ore, and 'hard' ore. The sandstone and clay ores differ from the associated barren sandstone and clay, with which they are interlayered and into which they grade, primarily in containing a variable proportion of amorphous manganese oxides, besides iron oxides and clayey material such as are present in the barren beds. The 'hard' ore is sandstone that has been impregnated with opal and calcite and in which the original amorphous manganese oxides have been largely converted to psilomelane and manganite. The average manganese content of the sandstone and clay ores is between 3 and 4 percent and that of the 'hard' ore is between 6 and 7 percent. The ore contains an average of 3 percent of iron, 0

  16. 32 CFR 644.523 - Restricting future of artillery and other ranges.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Contamination from Proposed Excess Land and Improvements § 644.523 Restricting future of artillery and other... will be based solely on the type and/or extent of contamination. If land is contaminated to such...

  17. 32 CFR 644.523 - Restricting future of artillery and other ranges.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Contamination from Proposed Excess Land and Improvements § 644.523 Restricting future of artillery and other... will be based solely on the type and/or extent of contamination. If land is contaminated to such...

  18. 32 CFR 644.523 - Restricting future of artillery and other ranges.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Contamination from Proposed Excess Land and Improvements § 644.523 Restricting future of artillery and other... will be based solely on the type and/or extent of contamination. If land is contaminated to such...

  19. 32 CFR 644.523 - Restricting future of artillery and other ranges.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Contamination from Proposed Excess Land and Improvements § 644.523 Restricting future of artillery and other... will be based solely on the type and/or extent of contamination. If land is contaminated to such...

  20. Diverse opportunities in defence

    NASA Astrophysics Data System (ADS)

    Brown, Gareth

    2016-08-01

    Working at the UK's defence laboratory gives Gareth Brown the ability to apply his physics and mathematics knowledge to real-world applications - and not necessarily in the ways you might expect. This article is Crown copyright

  1. Tactical nuclear weapons responsibility: Ordnance versus field artillery. Study project

    SciTech Connect

    Fields, J.A.

    1990-03-08

    There has existed and still exists an operational dichotomy in the area of the provision of tactical nuclear weapons to United States Army forces versus those allied forces in a combined theater of operations. Specifically, within the NATO environment and to a very small degree within Combined Forces Korea, there exists a condition where tactical nuclear weapons are supplied to the U.S. firing unit by an organization under the proponency of the Ordnance Corps. On the other hand, within the same theater, the non-U.S. force receives their tactical nuclear weapons by an organization under the proponency of the Field Artillery. This paper will examine the functions performed by this duplication of supply organizations and briefly list the supporting structure. It will then explore any possible purpose for the duplication which would justify this apparent mission replication. Discussion will then follow which will list the pros and cons of staying with the status quo or the possible assignment of the supply function to a single branch proponency. Conclusions are then drawn and recommendations made for improving the current system of tactical nuclear weapon support.

  2. Research on optoelectronic technology for detecting rifling of artillery online

    NASA Astrophysics Data System (ADS)

    Ma, Hong; Che, Ying; Shen, Yuzhi; Bai, Baoxing

    1996-10-01

    In this report, an optoelectronics instrument is introduced, in which the technology of laser alignment, the technology of computer image identification, and the principle of optical triangulation are used to inspect the contour and the internal surface quality of rifling in artillery barrel with real-time and automatically. This instrument is composed of laser aligning system, optical triangulation system, CCD camera system, computer image processing and identification system and computer-controlled system, the photoelectric targets of the caliber gauging system, of the CCD camera system and of laser aligning system, are all fixed in the chamber of the cutter of the boring tool, and they compose the photoelectric probe. When the boring tool bores the barrel, the light coming from the semiconductor laser which is located in the photoelectric probe, is reflected by the internal surface of the barrel and then received by 1D CCD. By the aid of optical triangulation operation, the radius of the rifling can be obtained, in the mean time, the image information of internal surface of the barrel, which is obtained by CCD is fed to be processed by computer image processing and identification system, and then the classified results can be given. The magnitude of deviation of the boring cutter from its ideal boring line, is provided by the laser aligning system with real time, the feedback system can revise the position of the boring tool whenever necessary. The caliber gauging precision of this instrument is +/- 0.005mm.

  3. The insanity defence.

    PubMed

    Milliken, A D

    1985-08-01

    The recent A.P.A. Statement on the Insanity Defence is a document important to all psychiatrists and medicolegal professionals in North America. Its contents are reviewed and contrasted with current Canadian practice on the insanity defence, as well as the proposals of the Mental Disorder Project of the Canadian Department of Justice. The American Psychiatric Association's proposal on the definition of mental disorder is contrasted with the current practice. It is also suggested that the proposal of the Mental Disorder Project to change the disposition of insanity acquittees will lead to difficulties similar to those which provoked the current crisis in the United States.

  4. 32 CFR 644.523 - Restricting future of artillery and other ranges.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 4 2010-07-01 2010-07-01 true Restricting future of artillery and other ranges. 644.523 Section 644.523 National Defense Department of Defense (Continued) DEPARTMENT OF THE ARMY... concentration of fire, and the properties of these projectiles are such that many duds are deeply buried....

  5. Particulate emissions from U.S. Department of Defense artillery backblast testing.

    PubMed

    Gillies, John A; Kuhns, Hampden; Engelbrecht, Johann P; Uppapalli, Sebastian; Etyemezian, Vicken; Nikolich, George

    2007-05-01

    There is a dearth of information on dust emissions from sources that are unique to the U.S. Department of Defense testing and training activities. However, accurate emissions factors are needed for these sources so that military installations can prepare accurate particulate matter (PM) emission inventories. One such source, coarse and fine PM (PM10 and PM2.5) emissions from artillery backblast testing on improved gun positions, was characterized at the Yuma Proving Ground near Yuma, AZ, in October 2005. Fugitive emissions are created by the shockwave from artillery pieces, which ejects dust from the surface on which the artillery is resting. Other contributions of PM can be attributed to the combustion of the propellants. For a 155-mm howitzer firing a range of propellant charges or zones, amounts of emitted PM10 ranged from -19 g of PM10 per firing event for a zone 1 charge to 92 g of PM10 per firing event for a zone 5. The corresponding rates for PM2.5 were approximately 9 g of PM2.5 and 49 g of PM2.5 per firing. The average measured emission rates for PM1o and PM2.5 appear to scale with the zone charge value. The measurements show that the estimated annual contributions of PM10 (52.2 t) and PM2.5 (28.5 t) from artillery backblast are insignificant in the context of the 2002 U.S. Environment Protection Agency (EPA) PM emission inventory. Using national-level activity data for artillery fire, the most conservative estimate is that backblast would contribute the equivalent of 5 x 10(-4) % and 1.6 x 10(-3)% of the annual total PM10 and PM2.5 fugitive dust contributions, respectively, based on 2002 EPA inventory data.

  6. Field Artillery Ammunition Processing System (FAAPS) concept evaluation study. Ammunition Logistics Program

    SciTech Connect

    Kring, C.T.; Babcock, S.M.; Watkin, D.C.; Oliver, R.P.

    1992-06-01

    The Field Artillery Ammunition Processing System (FAAPS) is an initiative to introduce a palletized load system (PLS) that is transportable with an automated ammunition processing and storage system for use on the battlefield. System proponents have targeted a 20% increase in the ammunition processing rate over the current operation while simultaneously reducing the total number of assigned field artillery battalion personnel by 30. The overall objective of the FAAPS Project is the development and demonstration of an improved process to accomplish these goals. The initial phase of the FAAPS Project and the subject of this study is the FAAPS concept evaluation. The concept evaluation consists of (1) identifying assumptions and requirements, (2) documenting the process flow, (3) identifying and evaluating technologies available to accomplish the necessary ammunition processing and storage operations, and (4) presenting alternative concepts with associated costs, processing rates, and manpower requirements for accomplishing the operation. This study provides insight into the achievability of the desired objectives.

  7. Gas sampling and analysis results for demilitarization of M107, 155mm artillery shells by open detonation

    SciTech Connect

    Velsko, C., LLNL

    1997-11-01

    This report presents and evaluates the gas sampling and analysis data obtained by LLNL for the fourdemilitarization experiments executed in the contained underground facility at X tunnel of the Nevada Test Site (NTS) from December 1996 through March 1997. Each of the four experiments detonated M107, 155mm artillery shells, 6, 24, 24 and 60 respectively, using C4 donor charges, and produced combustion product gases which mixed with the air and tracer gases in the chamber. Bechtel Nevada personnel performed the sampling configuration setup and operation of the field gas sampling and field analysis instrumentation. Continuous sampling and on-line analysis of gas from the chamber, as well as discrete sampling into 1 liter containers for post-shot analysis at LLNL, provided data to determine the gas compostion at detonation zero time. The carbon balance and emission factors of gaseous species produced by open detonation (OD) of M107 shells with C4 donor charges are presented and compared to OD of unconfined composition B explosive. The emission factors (EFs) for fixed gases from each test inthis series can be scaled as a function of net explosive weight (NEW) to estimate the amounts of gasesgenerated in 10,000 pound NEW demilitarization events. Changes in the trace gas concentrationsresulting from modification of the detonation setup can be used to monitor the extent of optimization.

  8. Modelling a man-portable air-defence (MANPAD) system with a rosette scan two-colour infrared (IR) and ultraviolet (UV) seeker

    NASA Astrophysics Data System (ADS)

    Kumar, Devinder; Smith, Leon; Richardson, Mark A.; Ayling, Richard; Barlow, Nick

    2014-10-01

    The Ultraviolet (UV) band of the electromagnetic (EM) spectrum has the potential to be used as the host medium for the operation of guided weapons. Unlike in the Infrared (IR), a target propelled by an air breathing jet engine produces no detectable radiation in the UV band, and is opaque to the background UV produced by the Sun. Successful engineering of spectral airborne IR countermeasures (CM) against existing two colour IR seekers has encouraged missile counter-countermeasure (CCM) designers to utilise the silhouette signature of an aircraft in the UV as a means of distinguishing between a true target and a flare CM. In this paper we describe the modelling process of a dual band IR and UV rosette scan seeker using CounterSim, a missile engagement and countermeasure simulation software package developed by Chemring Countermeasures Ltd. Results are shown from various simulated engagements of the dual band MANPAD with a C-130 Hercules modelled by Chemring Countermeasures. These results have been used to estimate the aircrafts' vulnerability to this MANPAD threat. A discussion on possible future optical countermeasures against dual band IR-UV seekers is given in conclusion to the simulation results.

  9. Surveillance, detection, and 3D infrared tracking of bullets, rockets, mortars, and artillery

    NASA Astrophysics Data System (ADS)

    Leslie, Daniel H.; Hyman, Howard; Moore, Fritz; Squire, Mark D.

    2001-09-01

    We describe test results using the FIRST (Fast InfraRed Sniper Tracker) to detect, track, and range to bullets in flight for determining the location of the bullet launch point. The technology developed for the FIRST system can be used to provide detection and accurate 3D track data for other small threat objects including rockets, mortars, and artillery in addition to bullets. We discuss the radiometry and detection range for these objects, and discuss the trade-offs involved in design of the very fast optical system for acquisition, tracking, and ranging of these targets.

  10. Experimental investigation of dynamic motions of an internal part in an artillery projectile

    SciTech Connect

    Cornell, R.H.

    1985-06-04

    A Partially Restrained Internal Member (PRIM) in a particular developmental artillery projectile does not, seemingly, effect its flight performance. However present theory predicts that the PRIM should cause a reduction in spin and growth in yaw resulting in significant range loss. The gyroscope experiments described in this paper produced PRIM motions which are periodic in precession as well as nutation. These periodicities and their slow growth have not been previously addressed. A more complete theory of motion is needed to describe the dynamics of PRIM motion.

  11. Closure report for CAU Number 430: Buried Depleted Uranium Artillery Round Number 1, Tonopah Test Range

    SciTech Connect

    1997-02-01

    Corrective Action Unit (CAU) 430 consists of the Buried Depleted Uranium (DU) Artillery Round No. 1. This Closure Report presents the information obtained from investigate actions performed to justify the decision for clean closure of CAU 430 through ``No Further Action``. The site was thought to consist of a potentially unexploded W-79 Joint Test Assembly (JTA) test artillery projectile with high explosives (HE) and DU. The DU was substituted for Special Nuclear Materials to prevent a nuclear explosion and yet retain the physical characteristics of uranium for ballistic and other mechanical tests. The projectile was reportedly buried in one pit, approximately 5 to 10 feet (ft) deep. The objectives of the activities were to prepare the site for closure through locating and identifying the projectile, destroying the projectile and any remaining components, collecting soil samples to detect residual contamination resulting from projectile destruction, and finally, remediating residual contamination. This report contains the following five sections. Section 1.0 introduces the CAU and scope of work. Section 2.0 of this report presents the closure activities performed as part of this investigation. Waste disposition is discussed in Section 3.0. Closure investigation results are presented in Section 4.0, and references are presented in Section 5.0.

  12. Design and performance of a parachute recovery system to recover 155-mm- and 8-inch-diameter artillery shells

    SciTech Connect

    Waye, D.E.; Peterson, C.W.; Botner, W.T.

    1986-01-01

    A parachute recovery system has been developed and demonstrated for the recovery of 155-mm- and 8-inch-diameter artillery shells. The recovery system functions after being subjected to gun launch accelerations of up to 18,000 g's axially and up to 400,000 rad/sec/sup 2/ radially. The parachute is deployed while the shell is still spinning at about 250 revolutions per second. To deploy the parachute while the shell is spinning, a double-swivel system was developed. The deployment signal for the recovery system is provided by an electronic timer. Over 250 tests have been performed on both the 155-mm- and 8-inch-diameter artillery shell. Impact velocities are between 100 and 120 feet per second. The latest version of the recovery systems has been proven to be over 95% successful for the recovery of 8-inch-diameter artillery shells and over 85% successful for the recovery of 155-mm-diameter artillery shells.

  13. In Defence of the Lecture

    ERIC Educational Resources Information Center

    Webster, R. Scott

    2015-01-01

    In response to the lecture format coming under "attack" and being replaced by online materials and smaller tutorials, this paper attempts to offer not only a defence but also to assert that the potential value of the lecture is difficult to replicate through other learning formats. Some of the criticisms against lectures will be…

  14. Air

    MedlinePlus

    ... do to protect yourself from dirty air . Indoor air pollution and outdoor air pollution Air can be polluted indoors and it can ... this chart to see what things cause indoor air pollution and what things cause outdoor air pollution! Indoor ...

  15. Reliable discrimination of high explosive and chemical/biological artillery using acoustic UGS

    NASA Astrophysics Data System (ADS)

    Hohil, Myron E.; Desai, Sachi

    2005-10-01

    The Army is currently developing acoustic overwatch sensor systems that will provide extended range surveillance, detection, and identification for force protection and tactical security on the battlefield. A network of such sensors remotely deployed in conjunction with a central processing node (or gateway) will provide early warning and assessment of enemy threats, near real-time situational awareness to commanders, and may reduce potential hazards to the soldier. In contrast, the current detection of chemical/biological (CB) agents expelled into a battlefield environment is limited to the response of chemical sensors that must be located within close proximity to the CB agent. Since chemical sensors detect hazardous agents through contact, the sensor range to an airburst is the key-limiting factor in identifying a potential CB weapon attack. The associated sensor reporting latencies must be minimized to give sufficient preparation time to field commanders, who must assess if an attack is about to occur, has occurred, or if occurred, the type of agent that soldiers might be exposed to. The long-range propagation of acoustic blast waves from heavy artillery blasts, which are typical in a battlefield environment, introduces a feature for using acoustics and other disparate sensor technologies for the early detection and identification of CB threats. Employing disparate sensor technologies implies that warning of a potential CB attack can be provided to the solider more rapidly and from a safer distance when compared to that which conventional methods allow. This capability facilitates the necessity of classifying the types of rounds that have burst in a specified region in order to give both warning and provide identification of CB agents found in the area. In this paper, feature extraction methods based on the discrete wavelet transform (DWT) and multiresolution analysis facilitate the development of a robust classification algorithm that affords reliable

  16. The psychiatric defence and international criminal law.

    PubMed

    Tobin, John

    2007-01-01

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

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

    PubMed Central

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

    2015-01-01

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

  18. Look at nuclear artillery yield options using JANUS, a wargame simulation code

    SciTech Connect

    Andre, C.G.

    1982-06-15

    JANUS, a two-sided, interactive wargame simulation code, was used to explore how using each of several different yield options in a nuclear artillery shell might affect a tactical battlefield simulation. In a general sense, the results or outcomes of these simulations support the results or outcomes of previous studies. In these simulations the Red player knew of the anticipated nuclear capability of the Blue player. Neither side experienced a decisive win over the other, and both continued fighting and experienced losses that, under most historical circumstances, would have been termed unacceptable - that is, something else would have happened (the attack would have been called off). During play, each side had only fragmentary knowledge of the remaining resources on the other side - thus each side desired to continue fighting on the basis of known information. We found that the anticipated use of nuclear weapons by either side affects the character of a game significantly and that, if the employment of nuclear weapons is to have a decided effect on the progress and outcome of a battle, each side will have to have an adequate number of nuclear weapons. In almost all the simulations we ran using JANUS, enhanced radiation (ER) weapons were more effective than 1-kt fission weapons in imposing overall losses on Red. The typical visibility in the JANUS simulation limited each side's ability to acquire units deep into enemy territory and so the 10-kt fission weapon was not useful against enemy tanks that were not engaged in battle. (Troop safety constraints limited its use on tanks that were engaged in direct fire with the enemy).

  19. Simulation, human factors and defence anaesthesia.

    PubMed

    Mercer, S J; Whittle, C; Siggers, B; Frazer, R S

    2010-12-01

    Simulation in healthcare has come a long way since it's beginnings in the 1960s. Not only has the sophistication of simulator design increased, but the educational concepts of simulation have become much clearer. One particularly important area is that of non-technical skills (NTS) which has been developed from similar concepts in the aviation and nuclear industries. NTS models have been developed for anaesthetists and more recently for surgeons too. This has clear value for surgical team working and the recently developed Military Operational Surgical Training (MOST) course uses simulation and NTS to improve such team working. The scope for simulation in Defence medicine and anaesthesia does not stop here. Uses of simulation include pre-deployment training of hospital teams as well as Medical Emergency Response Team (MERT) and Critical Care Air Support Team (CCAST) staff. Future projects include developing Role 1 pre-deployment training. There is enormous scope for development in this important growth area of education and training. PMID:21302658

  20. Closure Report for CAU No. 430: Buried Depleted Uraniuim Artillery Round No. 1, Tonopah Test Range, Revision 0

    SciTech Connect

    1997-02-25

    1.1 Purpose This Closure Report presents the information obtained from investigative actions performed to justify the decision for clean closure of CAU 430 through "No Further Action." The investigative actions were performed per the Streamlined Approach for Environmental Restoration Plan, CA UNO. 430: Buried Depleted Uranium Artille~ Round No. 1, Tonopah Test Range (DOE/NV, 1996a) (hereafter referred to as the SAFER Plan). The Buried DU Artillery Round No. 1 is located approximately 1.1 kilometers (km) (0.7 mile [mi]) south of Avenue 13 in the test area south of Area 9 (Figure 1-2). The site was thought to consist of a potentially unexploded W-79 Joint Test Assembly (JTA) test artillery projectile with high explosives (HE) and DU. The DU was substituted for Special Nuclear Material to prevent a nuclear explosion and yet retain the physical characteristics of uranium for ballistic and other mechanical tests. The projectile was reportedly buried in one pit, approximately 5 to 10 feet (ft) deep (Smith, 1993; Smith, 1996; Quas, 1996). The exact location of the burial pit is unknown; however, three disturbed areas (Sites A, B, and C) were identified through geophysical surveys, site visits, and employee interviews as possible locations of the test projectile (Figure 1-3). Results of the investigation are summarized within this Closure Report. Additional information about the site and investigation activities may be found in the SAFER Plan (DOE/NV, 1996a). 1.2 Scope The objectives of the SAFER Plan (DOE/NV, 1996a) activities were to prepare the site for closure through locating and identi~ing the projectile (Buried DU Artillery Round No. 1), destroying the projectile and any remaining components, collecting soil samples to detect residual contamination resulting from projectile destruction, and finally, remediating residual contamination.

  1. Evaluation of optimal control type models for the human gunner in an Anti-Aircraft Artillery (AAA) system

    NASA Technical Reports Server (NTRS)

    Phatak, A. V.; Kessler, K. M.

    1975-01-01

    The selection of the structure of optimal control type models for the human gunner in an anti aircraft artillery system is considered. Several structures within the LQG framework may be formulated. Two basic types are considered: (1) kth derivative controllers; and (2) proportional integral derivative (P-I-D) controllers. It is shown that a suitable criterion for model structure determination can be based on the ensemble statistics of the tracking error. In the case when the ensemble tracking steady state error is zero, it is suggested that a P-I-D controller formulation be used in preference to the kth derivative controller.

  2. Platelets: at the nexus of antimicrobial defence.

    PubMed

    Yeaman, Michael R

    2014-06-01

    Platelets have traditionally been viewed as fragmentary mediators of coagulation. However, recent molecular and cellular evidence suggests that they have multiple roles in host defence against infection. From first-responders that detect pathogens and rapidly deploy host-defence peptides, to beacons that recruit and enhance leukocyte functions in the context of infection, to liaisons that facilitate the T cell-B cell crosstalk that is required in adaptive immunity, platelets represent a nexus at the intersection of haemostasis and antimicrobial host defence. In this Review, I consider recent insights into the antimicrobial roles of platelets, which are mediated both directly and indirectly to integrate innate and adaptive immune responses to pathogens.

  3. Altruistic defence behaviours in aphids

    PubMed Central

    2010-01-01

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

  4. UK photonics in defence and security

    NASA Astrophysics Data System (ADS)

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

    2008-10-01

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

  5. The defence of therapeutic privilege in Australia.

    PubMed

    Mulheron, Rachael

    2003-11-01

    Therapeutic privilege is a defence that excuses a medical practitioner or other health professional from complying with the requirements of full disclosure to a patient in circumstances where it is reasonably considered that such disclosure would be harmful to that patient's health or welfare. Although the concept originated in the United States, the defence has been applied in Australia, and was specifically endorsed as part of Australian law by the High Court in Rogers v Whitaker (1992) 175 CLR 479. However, there has been negligible application of the defence since that endorsement. This article examines the doctrine of therapeutic privilege in the present Australian medico-legal environment. After an examination of the concept and its three constituetent elements, the article canvasses the limited instances of judicial approval of the defence prior to Rogers v Whitaker. The author then analyses, by reference to reported and unreported case law, why the defence has been so narrowly interpreted since, such that it has come to occupy an almost untenable position in Australia's medical jurisprudence.

  6. Probiotics: beneficial factors of the defence system.

    PubMed

    Antoine, Jean Michel

    2010-08-01

    Probiotics, defined as living micro-organisms that provide a health benefit to the host when ingested in adequate amounts, have been used traditionally as food components to help the body to recover from diarrhoea. They are commonly ingested as part of fermented foods, mostly in fresh fermented dairy products. They can interact with the host through different components of the gut defence systems. There is mounting clinical evidence that some probiotics, but not all, help the defence of the host as demonstrated by either a shorter duration of infections or a decrease in the host's susceptibility to pathogens. Different components of the gut barrier can be involved in the strengthening of the body's defences: the gut microbiota, the gut epithelial barrier and the immune system. Many studies have been conducted in normal free-living subjects or in subjects during common infections like the common cold and show that some probiotic-containing foods can improve the functioning of or strengthen the body's defence. Specific probiotic foods can be included in the usual balanced diet of consumers to help them to better cope with the daily challenges of their environment.

  7. In Defence of the Classroom Science Demonstration

    ERIC Educational Resources Information Center

    McCrory, Paul

    2013-01-01

    Science demonstrations are often criticised for their passive nature, their gratuitous exploitation and their limited ability to develop scientific knowledge and understanding. This article is intended to present a robust defence of the use of demonstrations in the classroom by identifying some of their unique and powerful benefits--practical,…

  8. The Man-in-the-Middle Defence

    NASA Astrophysics Data System (ADS)

    Anderson, Ross

    The man-in-the-middle defence is all about rehabilitating Charlie. For 20 years we’ve worried about this guy in the middle, Charlie, who’s forever intercalating himself into the communications between Alice and Bob, and people have been very judgemental about poor Charlie, saying that Charlie is a wicked person. Well, we’re not entirely convinced.

  9. Malaysian Defence and E-Learning

    ERIC Educational Resources Information Center

    Juhary, Jowati binti

    2005-01-01

    This paper begins with an analysis of the changing security scenario in the Asian region, with special focus on Malaysian defence strategies and foreign policies. Beginning in the mid 1990s, the Malaysian government shifted its attention away from the counter insurgency strategies of the early decades of independence to focus on wider questions of…

  10. PM2.5, oxidant defence and cardiorespiratory health: a review

    PubMed Central

    2013-01-01

    Airborne fine particle mass concentrations (PM2.5) are used for ambient air quality management worldwide based in part on known cardiorespiratory health effects. While oxidative stress is generally thought to be an important mechanism in determining these effects, relatively few studies have specifically examined how oxidant defence may impact susceptibility to particulate air pollution. Here we review studies that explore the impact of polymorphisms in anti-oxidant related genes or anti-oxidant supplementation on PM2.5-induced cardiorespiratory outcomes in an effort to summarize existing evidence related to oxidative stress defence and the health effects of PM2.5. Recent studies of PM-oxidative burden were also examined. In total, nine studies were identified and reviewed and existing evidence generally suggests that oxidant defence may modify the impact of PM2.5 exposure on various health outcomes, particularly heart rate variability (a measure of autonomic function) which was the most common outcome examined in the studies reviewed. Few studies examined interactions between PM2.5 and oxidant defence for respiratory outcomes, and in general studies focused primarily on acute health effects. Therefore, further evaluation of the potential modifying role of oxidant defence in PM2.5-induced health effects is required, particularly for chronic outcomes. Similarly, while an exposure metric that captures the ability of PM2.5 to cause oxidative stress may offer advantages over traditional mass concentration measurements, little epidemiological evidence is currently available to evaluate the potential benefits of such an approach. Therefore, further evaluation is required to determine how this metric may be incorporated in ambient air quality management. PMID:23641908

  11. PM2.5, oxidant defence and cardiorespiratory health: a review.

    PubMed

    Weichenthal, Scott A; Godri-Pollitt, Krystal; Villeneuve, Paul J

    2013-05-04

    Airborne fine particle mass concentrations (PM2.5) are used for ambient air quality management worldwide based in part on known cardiorespiratory health effects. While oxidative stress is generally thought to be an important mechanism in determining these effects, relatively few studies have specifically examined how oxidant defence may impact susceptibility to particulate air pollution. Here we review studies that explore the impact of polymorphisms in anti-oxidant related genes or anti-oxidant supplementation on PM2.5-induced cardiorespiratory outcomes in an effort to summarize existing evidence related to oxidative stress defence and the health effects of PM2.5. Recent studies of PM-oxidative burden were also examined. In total, nine studies were identified and reviewed and existing evidence generally suggests that oxidant defence may modify the impact of PM2.5 exposure on various health outcomes, particularly heart rate variability (a measure of autonomic function) which was the most common outcome examined in the studies reviewed. Few studies examined interactions between PM2.5 and oxidant defence for respiratory outcomes, and in general studies focused primarily on acute health effects. Therefore, further evaluation of the potential modifying role of oxidant defence in PM2.5-induced health effects is required, particularly for chronic outcomes. Similarly, while an exposure metric that captures the ability of PM2.5 to cause oxidative stress may offer advantages over traditional mass concentration measurements, little epidemiological evidence is currently available to evaluate the potential benefits of such an approach. Therefore, further evaluation is required to determine how this metric may be incorporated in ambient air quality management.

  12. Streamlined approach for environmental restoration plan for corrective action unit 430, buried depleted uranium artillery round No. 1, Tonopah test range

    SciTech Connect

    1996-09-01

    This plan addresses actions necessary for the restoration and closure of Corrective Action Unit (CAU) No. 430, Buried Depleted Uranium (DU) Artillery Round No. 1 (Corrective Action Site No. TA-55-003-0960), a buried and unexploded W-79 Joint Test Assembly (JTA) artillery test projectile with high explosives (HE), at the U.S. Department of Energy, Nevada Operations Office (DOE/NV) Tonopah Test Range (TTR) in south-central Nevada. It describes activities that will occur at the site as well as the steps that will be taken to gather adequate data to obtain a notice of completion from Nevada Division of Environmental Protection (NDEP). This plan was prepared under the Streamlined Approach for Environmental Restoration (SAFER) concept, and it will be implemented in accordance with the Federal Facility Agreement and Consent Order (FFACO) and the Resource Conservation and Recovery Act (RCRA) Industrial Sites Quality Assurance Project Plan.

  13. Immune defence under extreme ambient temperature.

    PubMed

    Seppälä, Otto; Jokela, Jukka

    2011-02-23

    Owing to global climate change, the extreme weather conditions are predicted to become more frequent, which is suggested to have an even greater impact on ecological interactions than the gradual increase in average temperatures. Here, we examined whether exposure to high ambient temperature affects immune function of the great pond snail (Lymnaea stagnalis). We quantified the levels of several immune traits from snails maintained in a non-stressful temperature (15°C) and in an extreme temperature (30°C) that occurs in small ponds during hot summers. We found that snails exposed to high temperature had weaker immune defence, which potentially predisposes them to infections. However, while phenoloxidase and antibacterial activity of snail haemolymph were reduced at high temperature, haemocyte concentration was not affected. This suggests that the effect of high temperature on snail susceptibility to infections may vary across different pathogens because different components of invertebrate immune defence have different roles in resistance.

  14. Peptides as triggers of plant defence.

    PubMed

    Albert, Markus

    2013-12-01

    Plants are confronted with several biotic stresses such as microbial pathogens and other herbivores. To defend against such attackers, plants possess an array of pattern recognition receptors (PRRs) that sense the danger and consequently initiate a defence programme that prevents further damage and spreading of the pest. Characteristic pathogenic structures, so-called microbe-associated molecular patterns (MAMPs), serve as signals that allow the plant to sense invaders. Additionally, pathogens wound or damage the plant and the resulting release of damage-associated molecular patterns (DAMPs) serves as a warning signal. This review focuses on peptides that serve as triggers or amplifiers of plant defence and thus follow the definition of a MAMP or a DAMP. PMID:24014869

  15. The Man-in-the-Middle Defence

    NASA Astrophysics Data System (ADS)

    Anderson, Ross; Bond, Mike

    Eliminating middlemen from security protocols helps less than one would think. EMV electronic payments, for example, can be made fairer by adding an electronic attorney - a middleman which mediates access to a customer’s card. We compare middlemen in crypto protocols and APIs with those in the real world, and show that a man-in-the-middle defence is helpful in many circumstances. We suggest that the middleman has been unfairly demonised.

  16. Immune defence against Candida fungal infections.

    PubMed

    Netea, Mihai G; Joosten, Leo A B; van der Meer, Jos W M; Kullberg, Bart-Jan; van de Veerdonk, Frank L

    2015-10-01

    The immune response to Candida species is shaped by the commensal character of the fungus. There is a crucial role for discerning between colonization and invasion at mucosal surfaces, with the antifungal host defence mechanisms used during mucosal or systemic infection with Candida species differing substantially. Here, we describe how innate sensing of fungi by pattern recognition receptors and the interplay of immune cells (both myeloid and lymphoid) with non-immune cells, including platelets and epithelial cells, shapes host immunity to Candida species. Furthermore, we discuss emerging data suggesting that both the innate and adaptive immune systems display memory characteristics after encountering Candida species.

  17. Revenge of the phages: defeating bacterial defences.

    PubMed

    Samson, Julie E; Magadán, Alfonso H; Sabri, Mourad; Moineau, Sylvain

    2013-10-01

    Bacteria and their viral predators (bacteriophages) are locked in a constant battle. In order to proliferate in phage-rich environments, bacteria have an impressive arsenal of defence mechanisms, and in response, phages have evolved counter-strategies to evade these antiviral systems. In this Review, we describe the various tactics that are used by phages to overcome bacterial resistance mechanisms, including adsorption inhibition, restriction-modification, CRISPR-Cas (clustered regularly interspaced short palindromic repeats-CRISPR-associated proteins) systems and abortive infection. Furthermore, we consider how these observations have enhanced our knowledge of phage biology, evolution and phage-host interactions. PMID:23979432

  18. Herbivory: Caterpillar saliva beats plant defences

    NASA Astrophysics Data System (ADS)

    Musser, Richard O.; Hum-Musser, Sue M.; Eichenseer, Herb; Peiffer, Michelle; Ervin, Gary; Murphy, J. Brad; Felton, Gary W.

    2002-04-01

    Blood-feeding arthropods secrete special salivary proteins that suppress the defensive reaction they induce in their hosts. This is in contrast to herbivores, which are thought to be helpless victims of plant defences elicited by their oral secretions. On the basis of the finding that caterpillar regurgitant can reduce the amount of toxic nicotine released by the tobacco plant Nicotiana tabacum, we investigate here whether specific salivary components from the caterpillar Helicoverpa zea might be responsible for this suppression. We find that the enzyme glucose oxidase counteracts the production of nicotine induced by the caterpillar feeding on the plant.

  19. Clostridium difficile colitis: pathogenesis and host defence.

    PubMed

    Abt, Michael C; McKenney, Peter T; Pamer, Eric G

    2016-10-01

    Clostridium difficile is a major cause of intestinal infection and diarrhoea in individuals following antibiotic treatment. Recent studies have begun to elucidate the mechanisms that induce spore formation and germination and have determined the roles of C. difficile toxins in disease pathogenesis. Exciting progress has also been made in defining the role of the microbiome, specific commensal bacterial species and host immunity in defence against infection with C. difficile. This Review will summarize the recent discoveries and developments in our understanding of C. difficile infection and pathogenesis. PMID:27573580

  20. In Defence of Multimodal Re-Signification: A Response to Havard Skaar's "In Defence of Writing"

    ERIC Educational Resources Information Center

    Adami, Elisabetta

    2011-01-01

    Responding to "In defence of writing" by Havard Skaar, published in issue 43.1 of this journal (April 2009), the present article argues that (1) compared with text production "from scratch," producing texts through copy-and-paste requires a different type of--rather than less--semiotic work, and that (2) digitally produced writing may involve the…

  1. Science and outreach for planetary defence

    NASA Astrophysics Data System (ADS)

    Stavinschi, M.

    2011-10-01

    The recent IAA Planetary Defence Conference held in Romania, focused on a hot topic: from Threat to Action. It is true that we ought to protect the planet but also educate the population in this direction. Increasing rumours about pseudo-scientific issues, such as the impact with asteroids, comets or debris of spatial missions, the effects of the growing solar activity, the displacement of the terrestrial rotation axis following major earthquakes, let alone spreading news about the end-of-the-world, show how crucial it is to prepare people to understand what is going on in the universe and, in particular, on our planet, and how to deal with inevitable events. Another central question is in order: who should be in charge of this education? Perhaps the journalists, but they lack the necessary preparation to present correct and updated information to the public. Or the scientists, but they are extremely busy and concentrated on their projects aimed at defending the planet and at answering the vast array of questions that their research stirs up. Our goal is to answer the following question: to what extent is it the scientist's responsibility and to what extent the journalist's to educate people for the planetary defence? In addition, we shall suggest how they can effectively co-ordinate efforts to solve the current problems of a society submerged in increasingly sophisticated but decreasingly informed technologies.

  2. Insect-plant interactions: endocrine defences.

    PubMed

    Bowers, W S

    1984-01-01

    It is the inevitable consequence of evolution that competitive species living together in a restricted space must try to exclude each other. Plants and insects are prime examples of this eternal competition, and although neither of these is in danger of extinction, their mutual defensive strategies are of compelling interest to the human race. Plant defences based on the insecticidal activity of certain of their secondary chemicals are readily apparent. Only through research into the fundamentals of insect physiology and biochemistry are more subtle defensive mechanisms revealed, linked to the disruption of the insect endocrine system. A diverse number of chemical structures are found in plants, which interfere with hormone-mediated processes in insects. Examples include: mimics of the insect's juvenile hormones such as juvabione from the balsam fir and the juvocimenes from sweet basil, which lethally disrupt insect development, and the precocenes found in Ageratum species, which act as anti-juvenile hormonal agents. The latter appear to serve as 'suicide substrates', undergoing activation into cytotoxins when acted on by specialized enzymes resident in the insect endocrine gland (corpus allatum) that is responsible for juvenile hormone biosynthesis and secretion. Consideration of these plant defensive strategies, which have been reached through aeons of evolutionary experimentation, may assist the human race in its defences against its principal competitors for food, fibre and health.

  3. Cooperation in defence against a predator.

    PubMed

    Garay, József

    2009-03-01

    The origin and the evolutionary stability of cooperation between unrelated individuals is one of the key problems of evolutionary biology. In this paper, a cooperative defence game against a predator is introduced which is based on Hamilton's selfish herd theory and Eshel's survival game models. Cooperation is altruistic in the sense that the individual, which is not the target of the predator, helps the members of the group attacked by the predator and during defensive action the helper individual may also die in any attack. In order to decrease the long term predation risk, this individual has to carry out a high risk action. Here I show that this kind of cooperative behaviour can evolve in small groups. The reason for the emergence of cooperation is that if the predator does not kill a mate of a cooperative individual, then the survival probability of the cooperative individual will increase in two cases. If the mate is non-cooperative, then-according to the dilution effect, the predator confusion effect and the higher predator vigilance-the survival probability of the cooperative individual increases. The second case is when the mate is cooperative, because a cooperative individual has a further gain, the active help in defence during further predator attacks. Thus, if an individual can increase the survival rate of its mates (no matter whether the mate is cooperative or not), then its own predation risk will decrease.

  4. Aggregation, defence and warning signals: the evolutionary relationship.

    PubMed

    Ruxton, Graeme D; Sherratt, Thomas N

    2006-10-01

    In a seminal contribution, Fisher argued how distastefulness could incrementally evolve in a prey species that was distributed in family groups. Many defended prey species occur in aggregations, but did aggregation facilitate the evolution of defence as Fisher proposed or did the possession of a defence allow individuals to enjoy the benefits of group living? Contemporary theory suggests that it can work both ways: pre-existing defences can make the evolution of gregariousness easier, but gregariousness can also aid the evolution of defence and warning signals. Unfortunately, the key phylogenetic analyses to elucidate the ordering of events have been hampered by the relative rarity of gregarious species, which in itself indicates that aggregation is not a pre-requisite for defence. Like the underlying theory, experimental studies have not given a definitive answer to the relative timing of the evolution of defence and aggregation, except to demonstrate that both orderings are possible. Conspicuous signals are unlikely to have evolved in the absence of a defence and aggregated undefended prey are likely to be vulnerable to predation in the absence of satiation effects. It therefore seems most likely that defence generally preceded the evolution of both aggregation and signalling, but alternative routes may well be possible.

  5. Computed Tomography Technology: Development and Applications for Defence

    SciTech Connect

    Baheti, G. L.; Saxena, Nisheet; Tripathi, D. K.; Songara, K. C.; Meghwal, L. R.; Meena, V. L.

    2008-09-26

    Computed Tomography(CT) has revolutionized the field of Non-Destructive Testing and Evaluation (NDT and E). Tomography for industrial applications warrants design and development of customized solutions catering to specific visualization requirements. Present paper highlights Tomography Technology Solutions implemented at Defence Laboratory, Jodhpur (DLJ). Details on the technological developments carried out and their utilization for various Defence applications has been covered.

  6. Costs of inducible defence along a resource gradient.

    PubMed

    Brönmark, Christer; Lakowitz, Thomas; Nilsson, P Anders; Ahlgren, Johan; Lennartsdotter, Charlotte; Hollander, Johan

    2012-01-01

    In addition to having constitutive defence traits, many organisms also respond to predation by phenotypic plasticity. In order for plasticity to be adaptive, induced defences should incur a benefit to the organism in, for example, decreased risk of predation. However, the production of defence traits may include costs in fitness components such as growth, time to reproduction, or fecundity. To test the hypothesis that the expression of phenotypic plasticity incurs costs, we performed a common garden experiment with a freshwater snail, Radix balthica, a species known to change morphology in the presence of molluscivorous fish. We measured a number of predator-induced morphological and behavioural defence traits in snails that we reared in the presence or absence of chemical cues from fish. Further, we quantified the costs of plasticity in fitness characters related to fecundity and growth. Since plastic responses may be inhibited under limited resource conditions, we reared snails in different densities and thereby levels of competition. Snails exposed to predator cues grew rounder and thicker shells, traits confirmed to be adaptive in environments with fish. Defence traits were consistently expressed independent of density, suggesting strong selection from predatory molluscivorous fish. However, the expression of defence traits resulted in reduced growth rate and fecundity, particularly with limited resources. Our results suggest full defence in predator related traits regardless of resource availability, and costs of defence consequently paid in traits related to fitness. PMID:22291961

  7. Computed Tomography Technology: Development and Applications for Defence

    NASA Astrophysics Data System (ADS)

    Baheti, G. L.; Saxena, Nisheet; Tripathi, D. K.; Songara, K. C.; Meghwal, L. R.; Meena, V. L.

    2008-09-01

    Computed Tomography(CT) has revolutionized the field of Non-Destructive Testing and Evaluation (NDT&E). Tomography for industrial applications warrants design and development of customized solutions catering to specific visualization requirements. Present paper highlights Tomography Technology Solutions implemented at Defence Laboratory, Jodhpur (DLJ). Details on the technological developments carried out and their utilization for various Defence applications has been covered.

  8. Comparative analysis of passive defences in spiders (Araneae).

    PubMed

    Pekár, Stano

    2014-07-01

    Being frequent prey of many predators, including especially wasps and birds, spiders have evolved a variety of defence mechanisms. Here I studied patterns of passive defences, namely anachoresis, crypsis, masquerade, aposematism and Batesian mimicry, in spiders. Using published information pertaining more than 1000 spider species, the phylogenetic pattern of different passive defences (i.e. defences that decrease the risk of an encounter with the predator) was investigated. Furthermore, I studied the effect of foraging guild, geographical distribution and diel activity on the frequency of defences as these determine the predators diversity, presence and perception. I found that crypsis (background matching) combined with anachoresis (hiding) was the most frequent defence confined mainly to families/genera at the base of the tree. Aposematism (warning coloration) and Batesian mimicry (imitation of noxious/dangerous model) were found in taxa that branched later in the tree, and masquerade (imitation of inedible objects) was confined to families at intermediate positions of the tree. Aposematism and Batesian mimicry were restricted to a few lineages. Masquerade was used particularly by web-building species with nocturnal activity. Aposematism was rare but mainly used by web-building diurnal species. Batesian mimicry was frequently observed in cursorial species with diurnal activity. Cryptic species were more common in temperate zones, whereas aposematic and mimetic species were more common in the tropics. Here I show that the evolution of passive defences in spiders was influenced by the ecology of species. Then, I discuss the evolutionary significance of the particularly defences.

  9. Asymmetric selection and the evolution of extraordinary defences

    PubMed Central

    Urban, Mark C.; Bürger, Reinhard; Bolnick, Daniel I.

    2013-01-01

    Evolutionary biologists typically predict future evolutionary responses to natural selection by analyzing evolution on an adaptive landscape. Much theory assumes symmetric fitness surfaces even though many stabilizing selection gradients deviate from symmetry. Here we revisit Lande's adaptive landscape and introduce novel analytical theory that includes asymmetric selection. Asymmetric selection and the resulting skewed trait distributions bias equilibrium mean phenotypes away from fitness peaks, usually toward the flatter shoulder of the individual fitness surface. We apply this theory to explain a longstanding paradox in biology and medicine: the evolution of excessive defences against enemies. These so-called extraordinary defences can evolve in response to asymmetrical selection when marginal risks of insufficient defence exceed marginal costs of excessive defence. Eco-evolutionary feedbacks between population abundances and asymmetric selection further exaggerate these defences. Recognizing the effect of asymmetrical selection on evolutionary trajectories will improve the accuracy of predictions and suggest novel explanations for apparent sub-optimality. PMID:23820378

  10. Ecological mechanisms for the coevolution of mating systems and defence.

    PubMed

    Campbell, Stuart A

    2015-02-01

    The diversity of flowering plants is evident in two seemingly unrelated aspects of life history: sexual reproduction, exemplified by the stunning variation in flower form and function, and defence, often in the form of an impressive arsenal of secondary chemistry. Researchers are beginning to appreciate that plant defence and reproduction do not evolve independently, but, instead, may have reciprocal and interactive (coevolutionary) effects on each other. Understanding the mechanisms for mating-defence interactions promises to broaden our understanding of how ecological processes can generate these two rich sources of angiosperm diversity. Here, I review current research on the role of herbivory as a driver of mating system evolution, and the role of mating systems in the evolution of defence strategies. I outline different ecological mechanisms and processes that could generate these coevolutionary patterns, and summarize theoretical and empirical support for each. I provide a conceptual framework for linking plant defence with mating system theory to better integrate these two research fields.

  11. A saponin-detoxifying enzyme mediates suppression of plant defences

    NASA Astrophysics Data System (ADS)

    Bouarab, K.; Melton, R.; Peart, J.; Baulcombe, D.; Osbourn, A.

    2002-08-01

    Plant disease resistance can be conferred by constitutive features such as structural barriers or preformed antimicrobial secondary metabolites. Additional defence mechanisms are activated in response to pathogen attack and include localized cell death (the hypersensitive response). Pathogens use different strategies to counter constitutive and induced plant defences, including degradation of preformed antimicrobial compounds and the production of molecules that suppress induced plant defences. Here we present evidence for a two-component process in which a fungal pathogen subverts the preformed antimicrobial compounds of its host and uses them to interfere with induced defence responses. Antimicrobial saponins are first hydrolysed by a fungal saponin-detoxifying enzyme. The degradation product of this hydrolysis then suppresses induced defence responses by interfering with fundamental signal transduction processes leading to disease resistance.

  12. Kin recognition affects plant communication and defence.

    PubMed

    Karban, Richard; Shiojiri, Kaori; Ishizaki, Satomi; Wetzel, William C; Evans, Richard Y

    2013-04-01

    The ability of many animals to recognize kin has allowed them to evolve diverse cooperative behaviours; such ability is less well studied for plants. Many plants, including Artemisia tridentata, have been found to respond to volatile cues emitted by experimentally wounded neighbours to increase levels of resistance to herbivory. We report that this communication was more effective among A. tridentata plants that were more closely related based on microsatellite markers. Plants in the field that received cues from experimentally clipped close relatives experienced less leaf herbivory over the growing season than those that received cues from clipped neighbours that were more distantly related. These results indicate that plants can respond differently to cues from kin, making it less likely that emitters will aid strangers and making it more likely that receivers will respond to cues from relatives. More effective defence adds to a growing list of favourable consequences of kin recognition for plants.

  13. Triage in the defence medical services.

    PubMed

    Horne, Simon T; Vassallo, J

    2015-06-01

    Triage of patients into categories according to their need for intervention is a core part of military medical practice. This article reviews how triage has evolved in the Defence Medical Services and how it might develop in the context of recent research. In particular, a simple model demonstrates that the ideal sensitivity and specificity of a triage system depends upon the availability of transport and the capacity of the receiving units. As a result, we may need to fundamentally change the way we approach triage in order to optimise outcomes-especially if casualty evacuation timelines become longer and smaller medical units more prevalent on future operations. Some pragmatic options for change are discussed. Finally, other areas of current research around triage are highlighted, perhaps showing where triage may go next.

  14. Genomic insights into strategies used by Xanthomonas albilineans with its reduced artillery to spread within sugarcane xylem vessels

    PubMed Central

    2012-01-01

    identified, supposing that X. albilineans has a reduced artillery compared to other pathogenic Xanthomonas species. Particular attention has therefore been given to genomic features specific to X. albilineans making it more capable of evading sugarcane surveillance systems or resisting sugarcane defense systems. Conclusions This study confirms that X. albilineans is a highly distinctive species within the genus Xanthomonas, and opens new perpectives towards a greater understanding of the pathogenicity of this destructive sugarcane pathogen. PMID:23171051

  15. Specificity in Mesograzer-Induced Defences in Seagrasses

    PubMed Central

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

    2015-01-01

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

  16. Non-immunological defence mechanisms of the gut.

    PubMed Central

    Sarker, S A; Gyr, K

    1992-01-01

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

  17. Role of Host-Defence Peptides in Eye Diseases

    PubMed Central

    Kolar, Satya S.; McDermott, Alison M.

    2013-01-01

    The eye and its associated tissues including the lacrimal system and lids have evolved several defence mechanisms to prevent microbial invasion. Included among this armory are several host-defence peptides. These multifunctional molecules are being studied not only for their endogenous antimicrobial properties but also for their potential therapeutic effects. Here the current knowledge of host-defence peptide expression in the eye will be summarized. The role of these peptides in eye disease will be discussed with the primary focus being on infectious keratitis, inflammatory conditions including dry eye and wound healing. Finally the potential of using host-defence peptides and their mimetics/derivatives for the treatment and prevention of eye diseases is addressed. PMID:21584809

  18. Between-Population Outbreeding Affects Plant Defence

    PubMed Central

    Leimu, Roosa; Fischer, Markus

    2010-01-01

    Between-population crosses may replenish genetic variation of populations, but may also result in outbreeding depression. Apart from direct effects on plant fitness, these outbreeding effects can also alter plant-herbivore interactions by influencing plant tolerance and resistance to herbivory. We investigated effects of experimental within- and between-population outbreeding on herbivore resistance, tolerance and plant fitness using plants from 13 to 19 Lychnis flos-cuculi populations. We found no evidence for outbreeding depression in resistance reflected by the amount of leaf area consumed. However, herbivore performance was greater when fed on plants from between-population compared to within-population crosses. This can reflect outbreeding depression in resistance and/or outbreeding effects on plant quality for the herbivores. The effects of type of cross on the relationship between herbivore damage and plant fitness varied among populations. This demonstrates how between-population outbreeding effects on tolerance range from outbreeding depression to outbreeding benefits among plant populations. Finally, herbivore damage strengthened the observed outbreeding effects on plant fitness in several populations. These results raise novel considerations on the impact of outbreeding on the joint evolution of resistance and tolerance, and on the evolution of multiple defence strategies. PMID:20838662

  19. Middle Devonian liverwort herbivory and antiherbivore defence.

    PubMed

    Labandeira, Conrad C; Tremblay, Susan L; Bartowski, Kenneth E; VanAller Hernick, Linda

    2014-04-01

    To test the extent of herbivory in early terrestrial ecosystems, we examined compression-impression specimens of the late Middle Devonian liverwort Metzgeriothallus sharonae, from the Catskill Delta deposit of eastern New York state. Shale fragments of field-collected specimens were processed by applying liquid nitrocellulose on exposed surfaces. After drying, the film coatings were lifted off and mounted on microscope slides for photography. Unprocessed fragments were photographed under cedarwood oil for enhanced contrast. An extensive repertoire of arthropodan-mediated herbivory was documented, representing three functional feeding groups and nine subordinate plant-arthropod damage types (DTs). The herbivory is the earliest occurrence of external foliage-feeding and galling in the terrestrial fossil record. Our evidence indicates that thallus oil body cells, similar to the terpenoid-containing oil bodies of modern liverworts, were probably involved in the chemical defence of M. sharonae against arthropod herbivores. Based on damage patterns of terrestrial plants and an accompanying but sparse body-fossil record, Devonian arthropodan herbivores were significantly smaller compared to those of the later Palaeozoic. These data collectively suggest that a broad spectrum herbivory may have had a more important role in early terrestrial ecosystems than previously thought.

  20. Salinity change impairs pipefish immune defence.

    PubMed

    Birrer, Simone C; Reusch, Thorsten B H; Roth, Olivia

    2012-12-01

    Global change is associated with fast and severe alterations of environmental conditions. Superimposed onto existing salinity variations in a semi-enclosed brackish water body such as the Baltic Sea, a decrease in salinity is predicted due to increased precipitation and freshwater inflow. Moreover, we predict that heavy precipitation events will accentuate salinity fluctuations near shore. Here, we investigated how the immune function of the broad-nosed pipefish (Syngnathus typhle), an ecologically important teleost with sex-role reversal, is influenced by experimentally altered salinities (control: 18 PSU, lowered: 6 PSU, increased: 30 PSU) upon infection with bacteria of the genus Vibrio. Salinity changes resulted in increased activity and proliferation of immune cells. However, upon Vibrio infection, individuals at low salinity were unable to mount specific immune response components, both in terms of monocyte and lymphocyte cell proliferation and immune gene expression compared to pipefish kept at ambient salinities. We interpret this as resource allocation trade-off, implying that resources needed for osmoregulation under salinity stress are lacking for subsequent activation of the immune defence upon infection. Our data suggest that composition of small coastal fish communities may change due to elevated environmental stress levels and the incorporated consequences thereof. PMID:22982326

  1. Salinity change impairs pipefish immune defence.

    PubMed

    Birrer, Simone C; Reusch, Thorsten B H; Roth, Olivia

    2012-12-01

    Global change is associated with fast and severe alterations of environmental conditions. Superimposed onto existing salinity variations in a semi-enclosed brackish water body such as the Baltic Sea, a decrease in salinity is predicted due to increased precipitation and freshwater inflow. Moreover, we predict that heavy precipitation events will accentuate salinity fluctuations near shore. Here, we investigated how the immune function of the broad-nosed pipefish (Syngnathus typhle), an ecologically important teleost with sex-role reversal, is influenced by experimentally altered salinities (control: 18 PSU, lowered: 6 PSU, increased: 30 PSU) upon infection with bacteria of the genus Vibrio. Salinity changes resulted in increased activity and proliferation of immune cells. However, upon Vibrio infection, individuals at low salinity were unable to mount specific immune response components, both in terms of monocyte and lymphocyte cell proliferation and immune gene expression compared to pipefish kept at ambient salinities. We interpret this as resource allocation trade-off, implying that resources needed for osmoregulation under salinity stress are lacking for subsequent activation of the immune defence upon infection. Our data suggest that composition of small coastal fish communities may change due to elevated environmental stress levels and the incorporated consequences thereof.

  2. Middle Devonian liverwort herbivory and antiherbivore defence.

    PubMed

    Labandeira, Conrad C; Tremblay, Susan L; Bartowski, Kenneth E; VanAller Hernick, Linda

    2014-04-01

    To test the extent of herbivory in early terrestrial ecosystems, we examined compression-impression specimens of the late Middle Devonian liverwort Metzgeriothallus sharonae, from the Catskill Delta deposit of eastern New York state. Shale fragments of field-collected specimens were processed by applying liquid nitrocellulose on exposed surfaces. After drying, the film coatings were lifted off and mounted on microscope slides for photography. Unprocessed fragments were photographed under cedarwood oil for enhanced contrast. An extensive repertoire of arthropodan-mediated herbivory was documented, representing three functional feeding groups and nine subordinate plant-arthropod damage types (DTs). The herbivory is the earliest occurrence of external foliage-feeding and galling in the terrestrial fossil record. Our evidence indicates that thallus oil body cells, similar to the terpenoid-containing oil bodies of modern liverworts, were probably involved in the chemical defence of M. sharonae against arthropod herbivores. Based on damage patterns of terrestrial plants and an accompanying but sparse body-fossil record, Devonian arthropodan herbivores were significantly smaller compared to those of the later Palaeozoic. These data collectively suggest that a broad spectrum herbivory may have had a more important role in early terrestrial ecosystems than previously thought. PMID:24372344

  3. Activation of defence reactions in Solanaceae: where is the specificity?

    PubMed

    Desender, Sabine; Andrivon, Didier; Val, Florence

    2007-01-01

    When a potential pathogen attempts to infect a plant, biochemical and molecular communication takes place and leads to the induction of plant defence mechanisms. In the case of efficient defence, visible symptoms are restricted and the pathogen does not multiply (incompatible interaction); when defence is inefficient, the plant becomes rapidly infected (compatible interaction). During the last 30 years, a growing body of knowledge on plant-pathogen interactions has been gathered, and a large number of studies investigate the induction of various plant defence reactions by pathogens or by pathogen-derived compounds. However, as most papers focus on incompatible interactions, there is still a lack of understanding about the similarities and differences between compatible and incompatible situations. This review targets the question of specificity in Solanaceae-pathogen interactions, by comparing defence patterns in plants challenged with virulent or avirulent pathogens (or with pathogen-associated molecular patterns from these). A special emphasis is made on analysing whether defence reactions in Solanaceae depend primarily on the type of elicitor, on the plant genotype/species, or on the type of interaction (compatible or incompatible).

  4. Induced plant defence responses: scientific and commercial development possibilities.

    PubMed

    Dietrich, R A; Lawton, K; Friedrich, L; Cade, R; Willits, M; Maleck, K

    1999-01-01

    Recent work has demonstrated that plants have endogenous defence mechanisms that can be induced as a response to attack by insects and pathogens. There are two well-studied examples of these induced defence responses. Systemic acquired resistance (SAR) results in increased resistance to a broad spectrum of pathogens throughout a plant in response to localized necrosis caused by pathogen infection. The second example is the systemic induction of proteinase inhibitors to deter feeding by herbivores following an initial event of feeding. In addition, there is now preliminary evidence for other induced defence response pathways. By understanding the breadth of induced defence responses and the mechanisms used to control these pathways, novel plant protection strategies may be developed for use in agronomic settings. Rather than reducing crop losses caused by pests or pathogens by using chemicals that are designed to kill the offending organism, the plant's own defence mechanisms can be used to limit damage due to pests. Novel crop protection strategies based on genetic or chemical regulation of these induced responses show great potential. The first example of a crop protection product that acts by inducing an endogenous defence response pathway is now on the market. Bion reduces the level of pathogen infection in plants by activating SAR.

  5. 6. PHOTOGRAPHIC COPY OF ORIGINAL CONSTRUCTION DRAWING, DATED MAY 15, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. PHOTOGRAPHIC COPY OF ORIGINAL CONSTRUCTION DRAWING, DATED MAY 15, 1919, 7TH CAVALRY CANTONMENT POST EXCHANGE, WAR DEPARTMENT, CONSTRUCTION DIVISION, PLAN No. 357, COPY ON FILE IN THE ENVIRONMENTAL MANAGEMENT OFFICE, FORT BLISS - Fort Bliss, 7th Cavalry Buildings, U.S. Army Air Defence Artillery Center & Fort Bliss, El Paso, El Paso County, TX

  6. 4. PHOTOGRAPHIC COPY OF ORIGINAL CONSTRUCTION DRAWING, DATED MAY 13, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. PHOTOGRAPHIC COPY OF ORIGINAL CONSTRUCTION DRAWING, DATED MAY 13, 1919, DETACHMENT BARRACK WITHOUT MESS, WAR DEPARTMENT, CONSTRUCTION DIVISION, PLAN # 353, COPY ON FILE IN THE ENVIRONMENTAL MANAGEMENT OFFICE, FORT BLISS - Fort Bliss, 7th Cavalry Buildings, U.S. Army Air Defence Artillery Center & Fort Bliss, El Paso, El Paso County, TX

  7. 8. PHOTOGRAPHIC COPY OF AERIAL PHOTOGRAPH, DATED CA. 19201925, FORT ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    8. PHOTOGRAPHIC COPY OF AERIAL PHOTOGRAPH, DATED CA. 1920-1925, FORT BLISS, ARROW POINTS TO 7TH CAVALRY CANTONMENT, COPY ON FILE IN THE ENVIRONMENTAL MANAGEMENT OFFICE, FORT BLISS - Fort Bliss, 7th Cavalry Buildings, U.S. Army Air Defence Artillery Center & Fort Bliss, El Paso, El Paso County, TX

  8. 5. PHOTOGRAPHIC COPY OF ORIGINAL CONSTRUCTION DRAWING, DATED JUNE 14, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    5. PHOTOGRAPHIC COPY OF ORIGINAL CONSTRUCTION DRAWING, DATED JUNE 14, 1919, 7TH CAVALRY CANTONMENT MESS BUILDING, WAR DEPARTMENT, CONSTRUCTION DIVISION, PLAN No. 316A, COPY ON FILE IN THE ENVIRONMENTAL MANAGEMENT OFFICE, FORT BLISS - Fort Bliss, 7th Cavalry Buildings, U.S. Army Air Defence Artillery Center & Fort Bliss, El Paso, El Paso County, TX

  9. 3. PHOTOGRAPHIC COPY OF MASTER PLAN, DETAIL SITE PLAN, 7TH ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. PHOTOGRAPHIC COPY OF MASTER PLAN, DETAIL SITE PLAN, 7TH CAVALRY BUILDINGS, DATED SEPTEMBER 10, 1951, SEE ARROW, DRAWING # BM-036, COPY ON FILE IN THE ENVIRONMENTAL MANAGEMENT OFFICE, FORT BLISS - Fort Bliss, 7th Cavalry Buildings, U.S. Army Air Defence Artillery Center & Fort Bliss, El Paso, El Paso County, TX

  10. 11. PHOTOGRAPHIC COPY OF ORIGINAL PHOTOGRAPH, DATED APRIL 29, 1926, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    11. PHOTOGRAPHIC COPY OF ORIGINAL PHOTOGRAPH, DATED APRIL 29, 1926, 7TH CAVALRY CANTONMENT MESS HALL, NATIONAL ARCHIVES PHOTOGRAPH, RECORD GROUP 92, GEOGRAPHIC FILE, 1922-1935, No. 600-1, FORT BLISS - Fort Bliss, 7th Cavalry Buildings, U.S. Army Air Defence Artillery Center & Fort Bliss, El Paso, El Paso County, TX

  11. 10. PHOTOGRAPHIC COPY OF ORIGINAL PHOTOGRAPH, DATED APRIL 29, 1926, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    10. PHOTOGRAPHIC COPY OF ORIGINAL PHOTOGRAPH, DATED APRIL 29, 1926, DOUBLE BARRACK, BUILDING 452, (ORIGINAL No. 655), SOUTH FRONT AND RIGHT SIDE, NATIONAL ARCHIVES PHOTOGRAPH, RECORD GROUP 92, GEOGRAPHIC FILE, 1922-1935, No. 600-1, FORT BLISS - Fort Bliss, 7th Cavalry Buildings, U.S. Army Air Defence Artillery Center & Fort Bliss, El Paso, El Paso County, TX

  12. 7. PHOTOGRAPHIC COPY OF ORIGINAL CONSTRUCTION DRAWING, DATED 1918, HORIZONAL ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. PHOTOGRAPHIC COPY OF ORIGINAL CONSTRUCTION DRAWING, DATED 1918, HORIZONAL SLIDING WINDOW DETAIL, WAR DEPARTMENT, MANUAL OF THE CONSTRUCTION DIVISION OF THE ARMY, WAR EMERGENCY CONSTRUCTION, SECTION C, ENGINEERING DIVISION, PLATE 5, CONSOLIDATED SUPPLY COMPANY PRINTERS, WASHINGTON - Fort Bliss, 7th Cavalry Buildings, U.S. Army Air Defence Artillery Center & Fort Bliss, El Paso, El Paso County, TX

  13. Tidal height influences the levels of enzymatic antioxidant defences in Mytilus edulis.

    PubMed

    Letendre, Julie; Chouquet, Bastien; Manduzio, Hélène; Marin, Matthieu; Bultelle, Florence; Leboulenger, François; Durand, Fabrice

    2009-03-01

    We investigated the potential variability of enzymatic antioxidant activities in blue mussels Mytilus edulis from a single intertidal population but living at different tidal heights. Activity levels of antioxidant enzymes (Cu/Zn superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, glutathione transferase) were measured in the gills and digestive gland of mussels sampled at high shore (HS, air-exposure>6h/12h) and low shore (LS, air-exposure<2h/12h) of an intertidal zone (Yport, Normandie, France) for two consecutive autumns. In both tissues, levels of each enzymatic activity (except GST) were clearly higher in HS mussels than in LS for the two years. These results suggest an ability to acclimate the enzymatic antioxidant defences to the degree of undergone stress, confirming the importance of environmental conditions in the antioxidant responses. Therefore, the location of organisms on the shore should be taken into account in sampling for ecotoxicological studies.

  14. Defence and Security Research Coexistence, Coherence, and Convergence

    NASA Astrophysics Data System (ADS)

    Breant, Christian; Karock, Ulrich

    Defence and security research have coexisted at the European Union level since the inception of the European Defence Agency (EDA). The agency was established under a Joint Action of the Council of Ministers on 12 July 2004, "to support the Member States and the Council in their effort to improve European defence capabilities in the field of crisis management and to sustain the European Security and Defence Policy as it stands now and develops in the future".1 The political decision to create the EDA was taken at the Thessaloniki European Council on 19 and 20 June 2003. Heads of State or Government tasked the Council bodies to undertake the requisite actions, in the course of 2004, to create an intergovernmental agency in the field of defence capabilities development, research, acquisition and armaments. The EDA has been located in Brussels right from the start. It is an intergovernmental EU agency under the Council's authority within the single institutional framework of the Union. It performs its mission in close cooperation with its participating Member States (pMS) and the European institutional actors.

  15. Plant defence as a complex and changing phenotype throughout ontogeny

    PubMed Central

    Ochoa-López, Sofía; Villamil, Nora; Zedillo-Avelleyra, Paulina; Boege, Karina

    2015-01-01

    Background and Aims Ontogenetic changes in anti-herbivore defences are common and result from variation in resource availability and herbivore damage throughout plant development. However, little is known about the simultaneous changes of multiple defences across the entire development of plants, and how such changes affect plant damage in the field. The aim of this study was to assess if changes in the major types of plant resistance and tolerance can explain natural herbivore damage throughout plant ontogeny. Methods An assessment was made of how six defensive traits, including physical, chemical and biotic resistance, simultaneously change across the major transitions of plant development, from seedlings to reproductive stages of Turnera velutina growing in the greenhouse. In addition, an experiment was performed to assess how plant tolerance to artificial damage to leaves changed throughout ontogeny. Finally, leaf damage by herbivores was evaluated in a natural population. Key Results The observed ontogenetic trajectories of all defences were significantly different, sometimes showing opposite directions of change. Whereas trichome density, leaf toughness, extrafloral nectary abundance and nectar production increased, hydrogen cyanide and compensatory responses decreased throughout plant development, from seedlings to reproductive plants. Only water content was higher at the intermediate juvenile ontogenetic stages. Surveys in a natural population over 3 years showed that herbivores consumed more tissue from juvenile plants than from younger seedlings or older reproductive plants. This is consistent with the fact that juvenile plants were the least defended stage. Conclusions The results suggest that defensive trajectories are a mixed result of predictions by the Optimal Defence Theory and the Growth–Differentiation Balance Hypothesis. The study emphasizes the importance of incorporating multiple defences and plant ontogeny into further studies for a more

  16. Chloroform-induced insanity defence confounds lawyer Lincoln.

    PubMed

    Spiegel, A D; Suskind, P B

    1997-12-01

    During an 1857 trial, the defence claimed that the accused should be absolved of wilful murder because an overdose of chloroform during surgery induced insanity. In a rare appearance as a prosecutor, Abraham Lincoln tried the case for the State of Illinois. Expert medical witnesses testified about the side effects of chloroform and chloroform-induced insanity. Significantly, Lincoln was not knowledgeable about medical jurisprudence and overlooked potential sources of evidence and expert witnesses. Defence lawyers presented an impressive array of physicians to testify about insanity, about chloroform and about the results of an overdosage during anaesthesia. Considering the state of scientific knowledge at the time, the trial was notable.

  17. Comparative genomics tools applied to bioterrorism defence.

    PubMed

    Slezak, Tom; Kuczmarski, Tom; Ott, Linda; Torres, Clinton; Medeiros, Dan; Smith, Jason; Truitt, Brian; Mulakken, Nisha; Lam, Marisa; Vitalis, Elizabeth; Zemla, Adam; Zhou, Carol Ecale; Gardner, Shea

    2003-06-01

    Rapid advances in the genomic sequencing of bacteria and viruses over the past few years have made it possible to consider sequencing the genomes of all pathogens that affect humans and the crops and livestock upon which our lives depend. Recent events make it imperative that full genome sequencing be accomplished as soon as possible for pathogens that could be used as weapons of mass destruction or disruption. This sequence information must be exploited to provide rapid and accurate diagnostics to identify pathogens and distinguish them from harmless near-neighbours and hoaxes. The Chem-Bio Non-Proliferation (CBNP) programme of the US Department of Energy (DOE) began a large-scale effort of pathogen detection in early 2000 when it was announced that the DOE would be providing bio-security at the 2002 Winter Olympic Games in Salt Lake City, Utah. Our team at the Lawrence Livermore National Lab (LLNL) was given the task of developing reliable and validated assays for a number of the most likely bioterrorist agents. The short timeline led us to devise a novel system that utilised whole-genome comparison methods to rapidly focus on parts of the pathogen genomes that had a high probability of being unique. Assays developed with this approach have been validated by the Centers for Disease Control (CDC). They were used at the 2002 Winter Olympics, have entered the public health system, and have been in continual use for non-publicised aspects of homeland defence since autumn 2001. Assays have been developed for all major threat list agents for which adequate genomic sequence is available, as well as for other pathogens requested by various government agencies. Collaborations with comparative genomics algorithm developers have enabled our LLNL team to make major advances in pathogen detection, since many of the existing tools simply did not scale well enough to be of practical use for this application. It is hoped that a discussion of a real-life practical application of

  18. Heat strain in the Canadian Forces chemical defence clothing: problems and solutions.

    PubMed

    McLellan, T M; Frim, J

    1994-12-01

    The Canadian Forces chemical defence protective clothing can induce an overwhelming strain on one's ability to regulate body temperature. Recently a number of investigations have been completed at the Defence and Civil Institute of Environmental Medicine that focused initially on understanding the interaction of metabolic rate, ambient temperature, and ambient vapour pressure on the severity of heat strain associated with wearing the protective clothing. This paper presents a summary of these initial studies together with an overview of different attempts to reduce heat strain during exercise in a hot environment. Factors such as improved aerobic fitness or a period of dry heat acclimation have little if any benefit on tolerance time while wearing the clothing during light or moderate exercise. The best solution to the problem of heat strain remains the use of microclimate conditioning (personal cooling), and these techniques have been successful for Naval and Air Force personnel. For our Land Forces, however, microclimate conditioning is not feasible until a lightweight high-energy power source is developed.

  19. Communal range defence in primates as a public goods dilemma.

    PubMed

    Willems, Erik P; Arseneau, T Jean M; Schleuning, Xenia; van Schaik, Carel P

    2015-12-01

    Classic socio-ecological theory holds that the occurrence of aggressive range defence is primarily driven by ecological incentives, most notably by the economic defendability of an area or the resources it contains. While this ecological cost-benefit framework has great explanatory power in solitary or pair-living species, comparative work on group-living primates has always found economic defendability to be a necessary, but not sufficient condition to account for the distribution of effective range defence across the taxon. This mismatch between theory and observation has recently been ascribed to a collective action problem among group members in, what is more informatively viewed as, a public goods dilemma: mounting effective defence of a communal range against intrusions by outgroup conspecifics. We here further develop this framework, and report on analyses at three levels of biological organization: across species, across populations within a single lineage and across groups and individuals within a single population. We find that communal range defence in primates very rarely involves collective action sensu stricto and that it is best interpreted as the outcome of opportunistic and strategic individual-level decisions. Whether the public good of a defended communal range is produced by solitary, joint or collective action is thus the outcome of the interplay between the unique characteristics of each individual, local and current socio-ecological conditions, and fundamental life-history traits of the species.

  20. A Strong Remedy to a Weak Ethical Defence of Homeopathy.

    PubMed

    Shaw, David

    2015-12-01

    In this article, I indicate and illustrate several flaws in a recent "ethical defence" of homeopathy. It transpires that the authors' arguments have several features in common with homeopathic remedies, including strong claims, a lack of logic or evidence, and no actual effect.

  1. Evolution of hosts paying manifold costs of defence

    PubMed Central

    Cressler, Clayton E.; Graham, Andrea L.; Day, Troy

    2015-01-01

    Hosts are expected to incur several physiological costs in defending against parasites. These include constitutive energetic (or other resource) costs of a defence system, facultative resource costs of deploying defences when parasites strike, and immunopathological costs of collateral damage. Here, we investigate the evolution of host recovery rates, varying the source and magnitude of immune costs. In line with previous work, we find that hosts paying facultative resource costs evolve faster recovery rates than hosts paying constitutive costs. However, recovery rate is more sensitive to changes in facultative costs, potentially explaining why constitutive costs are hard to detect empirically. Moreover, we find that immunopathology costs which increase with recovery rate can erode the benefits of defence, promoting chronicity of infection. Immunopathology can also lead to hosts evolving low recovery rate in response to virulent parasites. Furthermore, when immunopathology reduces fecundity as recovery rate increases (e.g. as for T-cell responses to urogenital chlamydiosis), then recovery and reproductive rates do not covary as predicted in eco-immunology. These results suggest that immunopathological and resource costs have qualitatively different effects on host evolution and that embracing the complexity of immune costs may be essential for explaining variability in immune defence in nature. PMID:25740895

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

    NASA Astrophysics Data System (ADS)

    van den Ancker, Hanneke; Jungerius, Pieter Dirk

    2013-04-01

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

  3. The Internal Ballistics of an Air Gun

    NASA Astrophysics Data System (ADS)

    Denny, Mark

    2011-02-01

    The internal ballistics of a firearm or artillery piece considers the pellet, bullet, or shell motion while it is still inside the barrel. In general, deriving the muzzle speed of a gunpowder firearm from first principles is difficult because powder combustion is fast and it very rapidly raises the temperature of gas (generated by gunpowder deflagration, or burning), which greatly complicates the analysis. A simple case is provided by air guns, for which we can make reasonable approximations that permit a derivation of muzzle speed. It is perhaps surprising that muzzle speed depends upon barrel length (artillerymen debated this dependence for centuries, until it was established experimentally and, later, theoretically ). Here we see that a simple physical analysis, accessible to high school or freshmen undergraduate physics students, not only derives realistic muzzle speed but also shows how it depends upon barrel length.

  4. Two-channel telemeter for use in a 3-inch spin air gun

    NASA Astrophysics Data System (ADS)

    Allen, F.

    1981-06-01

    A special two-channel telemeter-projectile system designed and built for use in a 3-in. spin air gun is described. The system allows batteries to be tested at a far lower cost than field testing. The telemeter projectile is unusually gun rugged an reusable in a simulated artillery environment. Test-battery current and voltage is continuously monitored by subcarrier oscillators. The fuze simulator contains logic components for controlling the battery land program, rather than using steady-state loads for the full flight. This telemeter system has potential applications in remote voltage monitoring over long periods of time.

  5. Project swiftsure final report: Destruction of chemical agent waste at Defence Research Establishment Suffield. Suffield special publication No. 170

    SciTech Connect

    McAndless, J.M.

    1995-12-31

    Swiftsure was a project to destroy old chemical warfare agent waste at the Defence Research Establishment Suffield Experimental Proving Ground. This report begins with an overview of the project and the consultation process, and describes the project planning and development process, the methods used to destroy the nerve agents, the contracting of a waste incinerator, the environmental protection plan, incinerator installation and testing, waste preparation and incineration operations, final waste product disposal and the environmental monitoring program. Appendices include details on the properties of the agents destroyed, sampling and analysis methods, and air quality monitoring specifications.

  6. World War I: an air war of consequence.

    PubMed

    Hallion, Richard P

    2014-06-01

    On December 17, 1903, the brothers Wilbur and Orville Wright flew the world's first successful airplane, following this with the first military airplane in 1908. (The 1908 Flyer was built by the brothers in response to a 1907 requirements specification for a 2-place aircraft capable of flying at 40 mph and able to be broken down and transported in a horse-drawn wagon. Technically, since it crashed during its demonstration program and was not formally delivered to the Army, it never became Army property. But the trials had been so impressive that the Army ordered a second, delivered in 1909.) Just six years later, Europe erupted in a general war. Often portrayed as a sideshow to the war on land and sea, the air war heralded the advent of mechanized warfare, the airplane being one of four great technological advances--the submarine, the tank, and radio communication--that, together, revolutionized military affairs. Aircraft reconnaissance influenced the conduct of military operations from the war's earliest days, and airborne observers routinely governed the fall of artillery barrages, crucially important in an artillery-dominant war.

  7. A Comparative Analysis of Sonic Defences in Bombycoidea Caterpillars

    PubMed Central

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

    2016-01-01

    Caterpillars have long been used as models for studying animal defence. Their impressive armour, including flamboyant warning colours, poisonous spines, irritating sprays, and mimicry of plant parts, snakes and bird droppings, has been extensively documented. But research has mainly focused on visual and chemical displays. Here we show that some caterpillars also exhibit sonic displays. During simulated attacks, 45% of 38 genera and 33% of 61 species of silk and hawkmoth caterpillars (Bombycoidea) produced sounds. Sonic caterpillars are found in many distantly-related groups of Bombycoidea, and have evolved four distinct sound types- clicks, chirps, whistles and vocalizations. We propose that different sounds convey different messages, with some designed to warn of a chemical defence and others, to startle predators. This research underscores the importance of exploring acoustic communication in juvenile insects, and provides a model system to explore how different signals have evolved to frighten, warn or even trick predators. PMID:27510510

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

    PubMed

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

    2016-08-11

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

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

    PubMed

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

    2016-01-01

    Caterpillars have long been used as models for studying animal defence. Their impressive armour, including flamboyant warning colours, poisonous spines, irritating sprays, and mimicry of plant parts, snakes and bird droppings, has been extensively documented. But research has mainly focused on visual and chemical displays. Here we show that some caterpillars also exhibit sonic displays. During simulated attacks, 45% of 38 genera and 33% of 61 species of silk and hawkmoth caterpillars (Bombycoidea) produced sounds. Sonic caterpillars are found in many distantly-related groups of Bombycoidea, and have evolved four distinct sound types- clicks, chirps, whistles and vocalizations. We propose that different sounds convey different messages, with some designed to warn of a chemical defence and others, to startle predators. This research underscores the importance of exploring acoustic communication in juvenile insects, and provides a model system to explore how different signals have evolved to frighten, warn or even trick predators. PMID:27510510

  10. Effects of myosmine on antioxidative defence in rat liver.

    PubMed

    Simeonova, Rumyana; Vitcheva, Vessela; Gorneva, Galina; Mitcheva, Mitka

    2012-03-01

    Myosmine [3-(1-pyrrolin-2-yl) pyridine] is an alkaloid structurally similar to nicotine, which is known to induce oxidative stress. In this study we investigated the effects of myosmine on enzymatic and non-enzymatic antioxidative defence in rat liver. Wistar rats received a single i.p. injection of 19 mg kg-1 of myosmine and an oral dose of 190 mg kg-1 by gavage. Nicotine was used as a positive control. Through either route of administration, myosmine altered the hepatic function by decreasing the levels of reduced glutathione, superoxide dismutase, and glutathione peroxidase activities on one hand and by increasing malondialdehyde, catalase, and glutathione reductase activity on the other. Compared to control, both routes caused significant lipid peroxidation in the liver and altered hepatic enzymatic and non-enzymatic antioxidative defences. The pro-oxidant effects of myosmine were comparable with those of nicotine. PMID:22450200

  11. Anosognosia as motivated unawareness: the 'defence' hypothesis revisited.

    PubMed

    Turnbull, Oliver H; Fotopoulou, Aikaterini; Solms, Mark

    2014-12-01

    Anosognosia for hemiplegia has seen a century of almost continuous research, yet a definitive understanding of its mechanism remains elusive. Essentially, anosognosic patients hold quasi-delusional beliefs about their paralysed limbs, in spite of all the contrary evidence, repeated questioning, and logical argument. We review a range of findings suggesting that emotion and motivation play an important role in anosognosia. We conclude that anosognosia involves (amongst other things) a process of psychological defence. This conclusion stems from a wide variety of clinical and experimental investigations, including data on implicit awareness of deficit, fluctuations in awareness over time, and dramatic effects upon awareness of psychological interventions such as psychotherapy, reframing of the emotional consequences of the paralysis, and first versus third person perspectival manipulations. In addition, we review and refute the (eight) arguments historically raised against the 'defence' hypothesis, including the claim that a defence-based account cannot explain the lateralised nature of the disorder. We argue that damage to a well-established right-lateralised emotion regulation system, with links to psychological processes that appear to underpin allocentric spatial cognition, plays a key role in anosognosia (at least in some patients). We conclude with a discussion of implications for clinical practice. PMID:25481464

  12. The protein quality control system manages plant defence compound synthesis.

    PubMed

    Pollier, Jacob; Moses, Tessa; González-Guzmán, Miguel; De Geyter, Nathan; Lippens, Saskia; Vanden Bossche, Robin; Marhavý, Peter; Kremer, Anna; Morreel, Kris; Guérin, Christopher J; Tava, Aldo; Oleszek, Wieslaw; Thevelein, Johan M; Campos, Narciso; Goormachtig, Sofie; Goossens, Alain

    2013-12-01

    Jasmonates are ubiquitous oxylipin-derived phytohormones that are essential in the regulation of many development, growth and defence processes. Across the plant kingdom, jasmonates act as elicitors of the production of bioactive secondary metabolites that serve in defence against attackers. Knowledge of the conserved jasmonate perception and early signalling machineries is increasing, but the downstream mechanisms that regulate defence metabolism remain largely unknown. Here we show that, in the legume Medicago truncatula, jasmonate recruits the endoplasmic-reticulum-associated degradation (ERAD) quality control system to manage the production of triterpene saponins, widespread bioactive compounds that share a biogenic origin with sterols. An ERAD-type RING membrane-anchor E3 ubiquitin ligase is co-expressed with saponin synthesis enzymes to control the activity of 3-hydroxy-3-methylglutaryl-CoA reductase (HMGR), the rate-limiting enzyme in the supply of the ubiquitous terpene precursor isopentenyl diphosphate. Thus, unrestrained bioactive saponin accumulation is prevented and plant development and integrity secured. This control apparatus is equivalent to the ERAD system that regulates sterol synthesis in yeasts and mammals but that uses distinct E3 ubiquitin ligases, of the HMGR degradation 1 (HRD1) type, to direct destruction of HMGR. Hence, the general principles for the management of sterol and triterpene saponin biosynthesis are conserved across eukaryotes but can be controlled by divergent regulatory cues.

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

    PubMed

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

    2016-07-01

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

  14. The circadian clock and defence signalling in plants.

    PubMed

    Sharma, Mayank; Bhatt, Deepesh

    2015-02-01

    The circadian clock is the internal time-keeping machinery in higher organisms. Cross-talk between the circadian clock and a diverse range of physiological processes in plants, including stress acclimatization, hormone signalling, photomorphogenesis and defence signalling, is currently being explored. Recent studies on circadian clock genes and genes involved in defence signalling have indicated a possible reciprocal interaction between the two. It has been proposed that the circadian clock shapes the outcome of plant-pathogen interactions. In this review, we highlight the studies carried out so far on two model plant pathogens, namely Pseudomonas syringae and Hyaloperonospora arabidopsidis, and the involvement of the circadian clock in gating effector-triggered immunity and pathogen-associated molecular pattern-triggered immunity. We focus on how the circadian clock gates the expression of various stress-related transcripts in a prolific manner to enhance plant fitness. An understanding of this dynamic relationship between clock and stress will open up new avenues in the understanding of endogenous mechanisms of defence signalling in plants.

  15. Anosognosia as motivated unawareness: the 'defence' hypothesis revisited.

    PubMed

    Turnbull, Oliver H; Fotopoulou, Aikaterini; Solms, Mark

    2014-12-01

    Anosognosia for hemiplegia has seen a century of almost continuous research, yet a definitive understanding of its mechanism remains elusive. Essentially, anosognosic patients hold quasi-delusional beliefs about their paralysed limbs, in spite of all the contrary evidence, repeated questioning, and logical argument. We review a range of findings suggesting that emotion and motivation play an important role in anosognosia. We conclude that anosognosia involves (amongst other things) a process of psychological defence. This conclusion stems from a wide variety of clinical and experimental investigations, including data on implicit awareness of deficit, fluctuations in awareness over time, and dramatic effects upon awareness of psychological interventions such as psychotherapy, reframing of the emotional consequences of the paralysis, and first versus third person perspectival manipulations. In addition, we review and refute the (eight) arguments historically raised against the 'defence' hypothesis, including the claim that a defence-based account cannot explain the lateralised nature of the disorder. We argue that damage to a well-established right-lateralised emotion regulation system, with links to psychological processes that appear to underpin allocentric spatial cognition, plays a key role in anosognosia (at least in some patients). We conclude with a discussion of implications for clinical practice.

  16. Focal accumulation of defences at sites of fungal pathogen attack

    PubMed Central

    Underwood, William; Somerville, Shauna C.

    2008-01-01

    Plants resist attack by haustorium-forming biotrophic and hemi-biotrophic fungi through fortification of the cell wall to prevent penetration through the wall and the subsequent establishment of haustorial feeding structures by the fungus. While the existence of cell wall-based defences has been known for many years, only recently have the molecular components contributing to such defences been identified. Forward genetic screens identified Arabidopsis mutants impaired in penetration resistance to powdery mildew fungi that were normally halted at the cell wall. Several loci contributing to penetration resistance have been identified and a common feature is the striking focal accumulation of proteins associated with penetration resistance at sites of interaction with fungal appressoria and penetration pegs. The focal accumulation of defence-related proteins and the deposition of cell wall reinforcements at sites of attempted fungal penetration represent an example of cell polarization and raise many questions of relevance, not only to plant pathology but also to general cell biology. PMID:18703493

  17. Herbivore induction of jasmonic acid and chemical defences reduce photosynthesis in Nicotiana attenuata.

    PubMed

    Nabity, Paul D; Zavala, Jorge A; DeLucia, Evan H

    2013-01-01

    Herbivory initiates a shift in plant metabolism from growth to defence that may reduce fitness in the absence of further herbivory. However, the defence-induced changes in carbon assimilation that precede this reallocation in resources remain largely undetermined. This study characterized the response of photosynthesis to herbivore induction of jasmonic acid (JA)-related defences in Nicotiana attenuata to increase understanding of these mechanisms. It was hypothesized that JA-induced defences would immediately reduce the component processes of photosynthesis upon attack and was predicted that wild-type plants would suffer greater reductions in photosynthesis than plants lacking JA-induced defences. Gas exchange, chlorophyll fluorescence, and thermal spatial patterns were measured together with the production of defence-related metabolites after attack and through recovery. Herbivore damage immediately reduced electron transport and gas exchange in wild-type plants, and gas exchange remained suppressed for several days after attack. The sustained reductions in gas exchange occurred concurrently with increased defence metabolites in wild-type plants, whereas plants lacking JA-induced defences suffered minimal suppression in photosynthesis and no increase in defence metabolite production. This suppression in photosynthesis occurred only after sustained defence signalling and defence chemical mobilization, whereas a short bout of feeding damage only transiently altered components of photosynthesis. It was identified that lipoxygenase signalling interacted with photosynthetic electron transport and that the resulting JA-related metabolites reduced photosynthesis. These data represent a metabolic cost to mounting a chemical defence against herbivory and link defence-signalling networks to the differential effects of herbivory on photosynthesis in remaining leaf tissues in a time-dependent manner.

  18. Neutrophils: Between Host Defence, Immune Modulation, and Tissue Injury

    PubMed Central

    Kruger, Philipp; Saffarzadeh, Mona; Weber, Alexander N. R.; Rieber, Nikolaus; Radsak, Markus; von Bernuth, Horst; Benarafa, Charaf; Roos, Dirk; Skokowa, Julia; Hartl, Dominik

    2015-01-01

    Neutrophils, the most abundant human immune cells, are rapidly recruited to sites of infection, where they fulfill their life-saving antimicrobial functions. While traditionally regarded as short-lived phagocytes, recent findings on long-term survival, neutrophil extracellular trap (NET) formation, heterogeneity and plasticity, suppressive functions, and tissue injury have expanded our understanding of their diverse role in infection and inflammation. This review summarises our current understanding of neutrophils in host-pathogen interactions and disease involvement, illustrating the versatility and plasticity of the neutrophil, moving between host defence, immune modulation, and tissue damage. PMID:25764063

  19. Analysis of direct punch velocity in professional defence

    NASA Astrophysics Data System (ADS)

    Lapkova, Dora; Adamek, Milan

    2016-06-01

    This paper is focused on analysis of a direct punch. Nowadays, professional defence is basic part of effective protection of people and property. There are many striking techniques and the goal of this research was to analyze the direct punch. The analysis is aimed to measure the velocity with help of high speed camera Olympus i-Speed 2 and then find the dependences of this velocity on input parameters. For data analysis two pieces of software were used - i-Speed Control Software and MINITAB. 111 participants took part in this experiment. The results are presented in this paper - especially dependence of mean velocity on time and difference in velocity between genders.

  20. Photosynthesis, photorespiration, and light signalling in defence responses.

    PubMed

    Kangasjärvi, Saijaliisa; Neukermans, Jenny; Li, Shengchun; Aro, Eva-Mari; Noctor, Graham

    2012-02-01

    Visible light is the basic energetic driver of plant biomass production through photosynthesis. The constantly fluctuating availability of light and other environmental factors means that the photosynthetic apparatus must be able to operate in a dynamic fashion appropriate to the prevailing conditions. Dynamic regulation is achieved through an array of homeostatic control mechanisms that both respond to and influence cellular energy and reductant status. In addition, light availability and quality are continuously monitored by plants through photoreceptors. Outside the laboratory growth room, it is within the context of complex changes in energy and signalling status that plants must regulate pathways to deal with biotic challenges, and this can be influenced by changes in the highly energetic photosynthetic pathways and in the turnover of the photosynthetic machinery. Because of this, defence responses are neither simple nor easily predictable, but rather conditioned by the nutritional and signalling status of the plant cell. This review discusses recent data and emerging concepts of how recognized defence pathways interact with and are influenced by light-dependent processes. Particular emphasis is placed on the potential roles of the chloroplast, photorespiration, and photoreceptor-associated pathways in regulating the outcome of interactions between plants and pathogenic organisms.

  1. Mutualistic ants as an indirect defence against leaf pathogens.

    PubMed

    González-Teuber, Marcia; Kaltenpoth, Martin; Boland, Wilhelm

    2014-04-01

    Mutualistic ants are commonly considered as an efficient indirect defence against herbivores. Nevertheless, their indirect protective role against plant pathogens has been scarcely investigated. We compared the protective role against pathogens of two different ant partners, a mutualistic and a parasitic ant, on the host plant Acacia hindsii (Fabaceae). The epiphytic bacterial community on leaves was evaluated in the presence and absence of both ant partners by cultivation and by 454 pyrosequencing of the 16S rRNA gene. Pathogen-inflicted leaf damage, epiphytic bacterial abundance (colony-forming units) and number of operational taxonomic units (OTUs) were significantly higher in plants inhabited by parasitic ants than in plants inhabited by mutualistic ants. Unifrac unweighted and weighted principal component analyses showed that the bacterial community composition on leaves changed significantly when mutualistic ants were removed from plants or when plants were inhabited by parasitic ants. Direct mechanisms provided by ant-associated bacteria would contribute to the protective role against pathogens. The results suggest that the indirect defence of mutualistic ants also covers the protection from bacterial plant pathogens. Our findings highlight the importance of considering bacterial partners in ant-plant defensive mutualisms, which can contribute significantly to ant-mediated protection from plant pathogens.

  2. Converting old shore protection structures into softer defence

    NASA Astrophysics Data System (ADS)

    Pranzini, Enzo

    2010-05-01

    Beach erosion has been affecting several developed countries since the middle of 19th century, which led to the construction of many different protection structures. These frequently proved to be ineffective locally, while being negative for downdrift coastal segments. In addition, such defence structures modified the coastal morphology, often transforming a sandy beach into a rocky coast. Softer shore protection projects have been developed in the past years, mostly accompanied by beach nourishment that uses quarried material or shelf sediments. This proved to be efficient in defending the beach, without negative fallouts on unprotected sectors. These techniques can be easily applied to beaches where no "archeaostructures" had been realized before. On the other hand, difficulties arise when such "old style" structures are to be replaced with softer techniques, since traditional hard defences usually cause such changes to beach profile that innovative ones become "too soft". Due to profile deepening in front of reflective structures, wave shoaling is reduced and energy dissipation concentrated in a narrow beach band. Restoring a milder profile needs a large amount of sediments and fine sands are not stable under those conditions. The new challenge for coastal engineers, coastal geomorphologists and coastal planners is managing the transition from old archaeostructures to new soft shore protection techniques. This process requires years of progressive adaptation - an unsuitable timing for politicians who demand fast results to be sold during the next elections. In Italy, along the Tuscany coast, where more than two kilometres of breakwaters protect each kilometre of coast, such a process has been initiated after a long phase of stakeholder participation in order to overcome public scepticism towards "invisible" defences. Detached breakwaters were lowered below sea level at Follonica and Marina di Pisa, while the number of groins is to be reduced at Marina di Massa

  3. To Gain the Academic Capital: The Conflict and Solution in the Dissertation Proposal Defence

    ERIC Educational Resources Information Center

    Ningning, Zhao

    2006-01-01

    Doctor candidates get the academic identity and academic capital in his field by the thesis writing. The dissertation proposal defence hold on the public field promotes the state of academic and legalizes the discipline of the academic community. During the dissertation proposal defence, doctor candidates may face three conflicts. The first is…

  4. An Exploratory Study of the Defence Mechanisms Used in Psychotherapy by Adults Who Have Intellectual Disabilities

    ERIC Educational Resources Information Center

    Newman, D. W.; Beail, N.

    2010-01-01

    Problem: A significant concept in psychodynamic theory and practice is that of defence mechanisms. The identifications of defences is a key task of the therapist and these are then used in the formulation and form part of the therapist's interventions. Case studies of psychotherapy with adults who have intellectual disabilities (IDs) suggest that…

  5. Identification of plant defence genes in canola using Arabidopsis cDNA microarrays.

    PubMed

    Schenk, P M; Thomas-Hall, S R; Nguyen, A V; Manners, J M; Kazan, K; Spangenberg, G

    2008-09-01

    We report the identification of novel defence genes in canola by using a cDNA microarray from Arabidopsis. We examined changes that occur in the abundance of transcripts corresponding to 2375 Arabidopsis expressed sequence tags (selected for defence gene identification) following inoculation of canola plants with the fungal necrotrophic leaf pathogen, Alternaria brassicicola. Microarray data obtained from this cross-hybridisation experiment were compared to expression profiles previously obtained from the equivalent Arabidopsis experiment. Homology searches using a canola expressed sequence tag database with approximately 6000 unique clones led to identification of canola defence genes. Pathogen-responsive transcripts included those associated to known defence genes, reactive oxygen species metabolism, disease resistance and regulatory genes, and cell maintenance/metabolism genes. Using specific primers for quantitative real-time reverse transcriptase PCR, gene expression profiles in canola were obtained that demonstrated coordinated defence responses, including systemic responses in distal tissue and salicylic acid- and methyl jasmonate-mediated signalling against A. brassicicola.

  6. Intensity of nest defence is related to offspring sex ratio in the great tit Parus major.

    PubMed Central

    Radford, A N; Blakey, J K

    2000-01-01

    Nest-defence behaviour of passerines is a form of parental investment. Parents are selected, therefore, to vary the intensity of their nest defence with respect to the value of their offspring. Great tit, Parus major, males were tested for their defence response to both a nest predator and playback of a great tit chick distress call. The results from the two trials were similar; males gave more alarm calls and made more perch changes if they had larger broods and if they had a greater proportion of sons in their brood. This is the first evidence for a relationship between nest-defence intensity and offspring sex ratio. Paternal quality, size, age and condition, lay date and chick condition did not significantly influence any of the measured nest-defence parameters. PMID:10787154

  7. Operation GRITROCK: the Defence Medical Services' story and emerging lessons from supporting the UK response to the Ebola crisis.

    PubMed

    Bricknell, Martin; Hodgetts, T; Beaton, K; McCourt, A

    2016-06-01

    This paper is a record of the UK Defence Medical Services (DMS) contribution to the UK response to the Ebola crisis in West Africa from the start of planning in July 2014 to the closure of the Ministry of Defence Ebola Virus Disease Treatment Unit at the end of June 2015. The context and wider UK government decisions are summarised. This paper describes the decisions and processes that resulted in the deployment of a DMS delivered Ebola Treatment Unit in conjunction with the Department for International Development and Save the Children. It covers arrangements for medical care for disease and non-battle injury, the Air Transportable Isolator and Force Health Protection policy, and finally, considers the medical lessons from this deployment. The core message is that the UK DMS are the only part of the UK health sector that is trained, equipped, manned and available to rapidly deploy and operate a complete medical unit as part of an international response to a health crisis. PMID:26487710

  8. Differential phenotypic and genetic expression of defence compounds in a plant–herbivore interaction along elevation

    PubMed Central

    Salgado, Ana L.; Suchan, Tomasz; Pellissier, Loïc; Rasmann, Sergio; Ducrest, Anne-Lyse

    2016-01-01

    Elevation gradients impose large differences in abiotic and biotic conditions over short distances, in turn, likely driving differences in gene expression more than would genetic variation per se, as natural selection and drift are less likely to fix alleles at such a narrow spatial scale. As elevation increases, the pressure exerted on plants by herbivores and on arthropod herbivores by predators decreases, and organisms spanning the elevation gradient are thus expected to show lower levels of defence at high elevation. The alternative hypothesis, based on the optimal defence theory, is that defence allocation should be higher in low-resource habitats such as those at high elevation, due to higher costs associated with tissue replacement. In this study, we analyse variation with elevation in (i) defence compound content in the plant Lotus corniculatus and (ii) gene expression associated with defence against predators in the specific phytophagous moth, Zygaena filipendulae. Both species produce cyanogenic glycosides (CNglcs) such as lotaustralin and linamarin as defence mechanisms, with the moth, in addition, being able to sequester CNglcs from its host plant. Specifically, we tested the assumption that the defence-associated phenotype in plants and the gene expression in the insect herbivore should covary between low- and high-elevation environments. We found that L. corniculatus accumulated more CNglcs at high elevation, a result in agreement with the optimal defence theory. By contrast, we found that the levels of expression in the defence genes of Z. filipendulae larvae were not related to the CNglc content of their host plant. Overall, expression levels were not correlated with elevation either, with the exception of the UGT33A1 gene, which showed a marginally significant trend towards higher expression at high elevation when using a simple statistical framework. These results suggest that the defence phenotype of plants against herbivores, and subsequent

  9. Plant defence against aphids: the PAD4 signalling nexus.

    PubMed

    Louis, Joe; Shah, Jyoti

    2015-02-01

    In Arabidopsis thaliana, PHYTOALEXIN DEFICIENT 4 (PAD4) functions as a key player in modulating defence against the phloem sap-feeding aphid Myzus persicae (Sülzer), more commonly known as the green peach aphid (GPA), an important pest of a wide variety of plants. PAD4 controls antibiosis and antixenosis against the GPA. In addition, PAD4 deters aphid feeding from sieve elements on Arabidopsis. In the past few years, substantial progress has been made in dissecting the role of PAD4 and its interaction with other signalling components in limiting aphid infestation. Several key genes/mechanisms involved in providing aphid resistance/susceptibility in Arabidopsis regulate the aphid infestation-stimulated expression of PAD4. Together, PAD4 and its interacting signalling partners provide a critical barrier to curtail GPA colonization of Arabidopsis.

  10. Mother-son incest as a defence against psychosis.

    PubMed

    Bachmann, K M; Bossi, J

    1993-09-01

    In the following, a case of mother-adult son incest is described and explained from a psychoanalytical viewpoint. Two theories are put forward: (a) Mother-son incest may occur as a defence against psychosis, and (b) the incest represents an unconscious search for triangulation, a process in which external authorities (such as, for example, a court of law) may function as surrogates for persons who have been missed in the pre-oedipal past. It is therefore possible to understand mother-son incest symbolically as an indicator of pre-oedipal needs of the son and of the mother's longing for the absent partner. The incest is, however, not only a cry for help; it is also to be regarded as an attempt to solve the problem for both people involved. Looked at in this way, new ways of understanding and new possibilities for therapy emerge.

  11. Potato skin proteome is enriched with plant defence components

    PubMed Central

    Barel, Gilli; Ginzberg, Idit

    2008-01-01

    Periderm is a tissue of secondary origin that replaces damaged epidermis. It can be found in underground plant organs, as an above-ground tissue of woody species (cork), and as a wound-healing tissue. Its outer layers are composed of phellem cells with suberized walls that constitute a protective barrier, preventing pathogen invasion and fluid loss. In potato, a model for periderm studies, periderm tissue replaces the epidermis early in tuber development and the suberized phellems constitute the tuber's skin. To identify factors involved in phellem/skin development and that play a role in its defensive characteristics, two-dimensional gel electrophoresis was used to compare the skin and parenchymatic flesh proteomes of young developing tubers. Proteins exhibiting differentially high signal intensity in the skin were sorted by functional categories. As expected, the differential skin proteome was enriched in proteins whose activity is characteristic of actively dividing tissues such as cell proliferation, C1 metabolism, and the oxidative respiratory chain. Interestingly, the major functional category consisted of proteins (63%) involved in plant defence responses to biotic and abiotic stresses. This group included three isozymes of caffeoyl-CoA O-methyltransferase and five isozymes of peroxidase that may play a role in suberization processes. The differential expression of these proteins in the skin was further verified by RT-PCR of their corresponding transcripts in skin and tuber flesh samples. The results presented here shed light on the early events in skin development and further expand the concept of the periderm as a protective tissue containing an array of plant defence components. PMID:18653692

  12. Brood parasitism selects for no defence in a cuckoo host.

    PubMed

    Krüger, Oliver

    2011-09-22

    In coevolutionary arms races, like between cuckoos and their hosts, it is easy to understand why the host is under selection favouring anti-parasitism behaviour, such as egg rejection, which can lead to parasites evolving remarkable adaptations to 'trick' their host, such as mimetic eggs. But what about cases where the cuckoo egg is not mimetic and where the host does not act against it? Classically, such apparently non-adaptive behaviour is put down to evolutionary lag: given enough time, egg mimicry and parasite avoidance strategies will evolve. An alternative is that absence of egg mimicry and of anti-parasite behaviour is stable. Such stability is at first sight highly paradoxical. I show, using both field and experimental data to parametrize a simulation model, that the absence of defence behaviour by Cape bulbuls (Pycnonotus capensis) against parasitic eggs of the Jacobin cuckoo (Clamator jacobinus) is optimal behaviour. The cuckoo has evolved massive eggs (double the size of bulbul eggs) with thick shells, making it very hard or impossible for the host to eject the cuckoo egg. The host could still avoid brood parasitism by nest desertion. However, higher predation and parasitism risks later in the season makes desertion more costly than accepting the cuckoo egg, a strategy aided by the fact that many cuckoo eggs are incorrectly timed, so do not hatch in time and hence do not reduce host fitness to zero. Selection will therefore prevent the continuation of any coevolutionary arms race. Non-mimetic eggs and absence of defence strategies against cuckoo eggs will be the stable, if at first sight paradoxical, result.

  13. Silicon-based plant defences, tooth wear and voles.

    PubMed

    Calandra, Ivan; Zub, Karol; Szafrańska, Paulina A; Zalewski, Andrzej; Merceron, Gildas

    2016-02-01

    Plant-herbivore interactions are hypothesized to drive vole population cycles through the grazing-induced production of phytoliths in leaves. Phytoliths act as mechanical defences because they deter herbivory and lower growth rates in mammals. However, how phytoliths impair herbivore performance is still unknown. Here, we tested whether the amount of phytoliths changes tooth wear patterns. If confirmed, abrasion from phytoliths could play a role in population crashes. We applied dental microwear texture analysis (DMTA) to laboratory and wild voles. Lab voles were fed two pelleted diets with differing amounts of silicon, which produced similar dental textures. This was most probably due to the loss of food mechanical properties through pelletization and/or the small difference in silicon concentration between diets. Wild voles were trapped in Poland during spring and summer, and every year across a population cycle. In spring, voles feed on silica-rich monocotyledons, while in the summer they also include silica-depleted dicotyledons. This was reflected in the results; the amount of silica therefore leaves a traceable record in the dental microwear texture of voles. Furthermore, voles from different phases of population cycles have different microwear textures. We tentatively propose that these differences result from grazing-induced phytolith concentrations. We hypothesize that the high amount of phytoliths in response to intense grazing in peak years may result in malocclusion and other dental abnormalities, which would explain how these silicon-based plant defences help provoke population crashes. DMTA could then be used to reconstruct vole population dynamics using teeth from pellets or palaeontological material. PMID:26889000

  14. The Australian Defence Force Mental Health Prevalence and Wellbeing Study: design and methods

    PubMed Central

    Hooff, Miranda Van; McFarlane, Alexander C.; Davies, Christopher E.; Searle, Amelia K.; Fairweather-Schmidt, A. Kate; Verhagen, Alan; Benassi, Helen; Hodson, Stephanie E.

    2014-01-01

    Background The Australian Defence Force (ADF) Mental Health Prevalence and Wellbeing Study (MHPWS) is the first study of mental disorder prevalence in an entire military population. Objective The MHPWS aims to establish mental disorder prevalence, refine current ADF mental health screening methods, and identify specific occupational factors that influence mental health. This paper describes the design, sampling strategies, and methodology used in this study. Method At Phase 1, approximately half of all regular Navy, Army, and Air Force personnel (n=24,481) completed self-report questionnaires. At Phase 2, a stratified sub-sample (n=1,798) completed a structured diagnostic interview to detect mental disorder. Based on data from non-responders, data were weighted to represent the entire ADF population (n=50,049). Results One in five ADF members met criteria for a 12-month mental disorder (22%). The most common disorder category was anxiety disorders (14.8%), followed by affective (9.5%) and alcohol disorders (5.2%). At risk ADF sub-groups were Army personnel, and those in the lower ranks. Deployment status did not have an impact on mental disorder rates. Conclusion This study has important implications for mental health service delivery for Australian and international military personnel as well as contemporary veterans. PMID:25206944

  15. Evolution of behavioural and cellular defences against parasitoid wasps in the Drosophila melanogaster subgroup.

    PubMed

    Lynch, Z R; Schlenke, T A; de Roode, J C

    2016-05-01

    It may be intuitive to predict that host immune systems will evolve to counter a broad range of potential challenges through simultaneous investment in multiple defences. However, this would require diversion of resources from other traits, such as growth, survival and fecundity. Therefore, ecological immunology theory predicts that hosts will specialize in only a subset of possible defences. We tested this hypothesis through a comparative study of a cellular immune response and a putative behavioural defence used by eight fruit fly species against two parasitoid wasp species (one generalist and one specialist). Fly larvae can survive infection by melanotically encapsulating wasp eggs, and female flies can potentially reduce infection rates in their offspring by laying fewer eggs when wasps are present. The strengths of both defences varied significantly but were not negatively correlated across our chosen host species; thus, we found no evidence for a trade-off between behavioural and cellular immunity. Instead, cellular defences were significantly weaker against the generalist wasp, whereas behavioural defences were similar in strength against both wasps and positively correlated between wasps. We investigated the adaptive significance of wasp-induced oviposition reduction behaviour by testing whether wasp-exposed parents produce offspring with stronger cellular defences, but we found no support for this hypothesis. We further investigated the sensory basis of this behaviour by testing mutants deficient in either vision or olfaction, both of which failed to reduce their oviposition rates in the presence of wasps, suggesting that both senses are necessary for detecting and responding to wasps.

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

    PubMed Central

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

    2014-01-01

    Host defences become increasingly costly as parasites breach successive lines of defence. Because selection favours hosts that successfully resist parasitism at the lowest possible cost, escalating coevolutionary arms races are likely to drive host defence portfolios towards ever more expensive strategies. We investigated the interplay between host defence portfolios and social parasite pressure by comparing 17 populations of two Temnothorax ant species. When successful, collective aggression not only prevents parasitation but also spares host colonies the cost of searching for and moving to a new nest site. However, once parasites breach the host's nest defence, host colonies should resort to flight as the more beneficial resistance strategy. We show that under low parasite pressure, host colonies more likely responded to an intruding Protomognathus americanus slavemaker with collective aggression, which prevented the slavemaker from escaping and potentially recruiting nest-mates. However, as parasite pressure increased, ant colonies of both host species became more likely to flee rather than to fight. We conclude that host defence portfolios shift consistently with social parasite pressure, which is in accordance with the degeneration of frontline defences and the evolution of subsequent anti-parasite strategies often invoked in hosts of brood parasites. PMID:25100690

  17. Tasting the difference: do multiple defence chemicals interact in Müllerian mimicry?

    PubMed

    Skelhorn, John; Rowe, Candy

    2005-02-01

    Müllerian mimicry, where two unpalatable species share a warning pattern, is classically believed to be a form of mutualism, where the species involved share the cost of predator education. The evolutionary dynamics of Müllerian mimicry have recently become a controversial subject, after mathematical models have shown that if minor alterations are made to assumptions about the way in which predators learn and forget about unpalatable prey, this textbook case of mutualism may not be mutualistic at all. An underlying assumption of these models is that Müllerian mimics possess the same defence chemical. However, some Müllerian mimics are known to possess different defence chemicals. Using domestic chicks as predators and coloured crumbs flavoured with either the same or different unpalatable chemicals as prey, we provide evidence that two defence chemicals can interact to enhance predator learning and memory. This indicates that Müllerian mimics that possess different defence chemicals are better protected than those that share a single defence chemical. These data provide insight into how multiple defence chemicals are perceived by birds,and how they influence the way birds learn and remember warningly coloured prey. They highlight the importance of considering how different toxins in mimicry rings can interact in the evolution and maintenance of Müllerian mimicry and could help to explain the remarkable variation in chemical defences found within and between species.

  18. Metabolomic Assessment of Induced and Activated Chemical Defence in the Invasive Red Alga Gracilaria vermiculophylla

    PubMed Central

    Nylund, Göran M.; Weinberger, Florian; Rempt, Martin; Pohnert, Georg

    2011-01-01

    In comparison with terrestrial plants the mechanistic knowledge of chemical defences is poor for marine macroalgae. This restricts our understanding in the chemically mediated interactions that take place between algae and other organisms. Technical advances such as metabolomics, however, enable new approaches towards the characterisation of the chemically mediated interactions of organisms with their environment. We address defence responses in the red alga Gracilaria vermiculophylla using mass spectrometry based metabolomics in combination with bioassays. Being invasive in the north Atlantic this alga is likely to possess chemical defences according to the prediction that well-defended exotics are most likely to become successful invaders in systems dominated by generalist grazers, such as marine macroalgal communities. We investigated the effect of intense herbivore feeding and simulated herbivory by mechanical wounding of the algae. Both processes led to similar changes in the metabolic profile. Feeding experiments with the generalist isopod grazer Idotea baltica showed that mechanical wounding caused a significant increase in grazer resistance. Structure elucidation of the metabolites of which some were up-regulated more than 100 times in the wounded tissue, revealed known and novel eicosanoids as major components. Among these were prostaglandins, hydroxylated fatty acids and arachidonic acid derived conjugated lactones. Bioassays with pure metabolites showed that these eicosanoids are part of the innate defence system of macroalgae, similarly to animal systems. In accordance with an induced defence mechanism application of extracts from wounded tissue caused a significant increase in grazer resistance and the up-regulation of other pathways than in the activated defence. Thus, this study suggests that G. vermiculophylla chemically deters herbivory by two lines of defence, a rapid wound-activated process followed by a slower inducible defence. By unravelling

  19. Metabolomic assessment of induced and activated chemical defence in the invasive red alga Gracilaria vermiculophylla.

    PubMed

    Nylund, Göran M; Weinberger, Florian; Rempt, Martin; Pohnert, Georg

    2011-01-01

    In comparison with terrestrial plants the mechanistic knowledge of chemical defences is poor for marine macroalgae. This restricts our understanding in the chemically mediated interactions that take place between algae and other organisms. Technical advances such as metabolomics, however, enable new approaches towards the characterisation of the chemically mediated interactions of organisms with their environment. We address defence responses in the red alga Gracilaria vermiculophylla using mass spectrometry based metabolomics in combination with bioassays. Being invasive in the north Atlantic this alga is likely to possess chemical defences according to the prediction that well-defended exotics are most likely to become successful invaders in systems dominated by generalist grazers, such as marine macroalgal communities. We investigated the effect of intense herbivore feeding and simulated herbivory by mechanical wounding of the algae. Both processes led to similar changes in the metabolic profile. Feeding experiments with the generalist isopod grazer Idotea baltica showed that mechanical wounding caused a significant increase in grazer resistance. Structure elucidation of the metabolites of which some were up-regulated more than 100 times in the wounded tissue, revealed known and novel eicosanoids as major components. Among these were prostaglandins, hydroxylated fatty acids and arachidonic acid derived conjugated lactones. Bioassays with pure metabolites showed that these eicosanoids are part of the innate defence system of macroalgae, similarly to animal systems. In accordance with an induced defence mechanism application of extracts from wounded tissue caused a significant increase in grazer resistance and the up-regulation of other pathways than in the activated defence. Thus, this study suggests that G. vermiculophylla chemically deters herbivory by two lines of defence, a rapid wound-activated process followed by a slower inducible defence. By unravelling

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

    PubMed Central

    Mostowy, Serge; Shenoy, Avinash R.

    2016-01-01

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

  1. Predator avoidance and immune defence: costs and trade-offs in snails.

    PubMed

    Rigby, M C; Jokela, J

    2000-01-22

    Organisms are often confronted by both predators and pathogens. Defending against such widely divergent enemies requires more than one type of defence. Multiple defences, however, raise the possibility of trade-offs among defences. We tested for such trade-offs by manipulating the level of predator-avoidance behaviour and immune function in the freshwater snail Lymnaea stagnalis (Gastropoda: Pulmonata). Our results show that predator avoidance and immune function had clear costs in terms of reproduction and survival. Further, we show that increased levels of predator-avoidance behaviour reduced the snails' ability to defend against potential pathogens. Predator-avoidance behaviour may thus have the additional indirect cost of reduced immunocompetence and increased susceptibility to pathogens. Our results suggest that ecological factors (e.g. predator density) may considerably modify the expression and costs of immune defences.

  2. Psychic skin: psychotic defences, borderline process and delusions.

    PubMed

    Schmidt, Martin

    2012-02-01

    In this paper, I apply the concept of psychic skin to analytic work with people suffering from personality disorders and psychoses. When psychoses emerge, the defensive skin which protects the ego is breached and violent unconscious forces rip through the personality. Some of the patients diagnosed as schizophrenic with whom I work have identified with archetypal characters such as Christ, Satan, John Lennon and the Queen. I attempt to show how the adoption of these inflated personas can serve as secondary psychic skins. Such delusional identifications can provide a protective shield to hide the denuded self and prevent intrusion from the external world. Through clinical example, I try to demonstrate how these archetypal 'second skins' can preserve life until internal and external conditions make it possible for the self to emerge. I contrast such psychotic identifications with 'thin-skinned' and 'thick-skinned' narcissism as well as 'defences of the self' in borderline states where the psychic skin may be damaged but does not disintegrate. I also look at the ways in which Jung's own personal experience was different from this and how he managed to avert psychotic breakdown.

  3. Caterpillar hairs as an anti-parasitoid defence

    NASA Astrophysics Data System (ADS)

    Kageyama, Azusa; Sugiura, Shinji

    2016-10-01

    Caterpillar hairs are thought to act as a physical barrier against natural enemies, including parasitoids. However, very few studies have experimentally demonstrated how hairs protect caterpillars from parasitoid oviposition. To clarify the importance of caterpillar hairs as an anti-parasitoid defence, we observed the generalist endoparasitoid Meteorus pulchricornis (Hymenoptera: Braconidae) attacking both smooth and hairy caterpillars under laboratory conditions. A female Meteorus pulchricornis uses its ovipositor to inject venom and lay a single egg inside host larvae. We placed a smooth Spodoptera litura (Lepidoptera: Noctuidae) caterpillar or a hairy Lymantria dispar japonica (Lepidoptera: Erebidae) caterpillar in front of parasitoid females. We observed that 100 % and 84 % of the parasitoids could successfully stab their ovipositors into the smooth larvae of S. litura and first instars of the hairy caterpillar L. dispar japonica, respectively. However, only 24 % of parasitoids could successfully stab their ovipositors into second-instar L. dispar japonica. A higher rate of successful stabs (94 %) by parasitoids was obtained by cutting the hairs of second instar L. dispar japonica much shorter than the parasitoid ovipositor. The results demonstrate that the long, thick hairs of second and later instars of L. dispar japonica function as a physical barrier against parasitoid oviposition.

  4. "Sleights of mind": delusions, defences, and self-deception.

    PubMed

    McKay, Ryan; Langdon, Robyn; Coltheart, Max

    2005-08-01

    Two different modes of theorising about delusions are explored. On the one hand is the motivational approach, which regards delusions as serving a defensive, palliative, even potentially adaptive function. On the other, is the cognitive deficit approach, which conceptualises delusions as explicitly pathological, involving abnormalities in ordinary cognitive processes. The former approach, prominently exemplified by the psychoanalytic tradition, was predominant historically, but has been challenged in recent years by the latter. Some grievances against psychoanalytic theory are briefly discussed, and it is argued that although the reasons for psychoanalysis falling into scientific disrepute are partly justified, the psychodynamic notion that motivation has access to the mechanisms of belief formation is of potentially crucial theoretical utility. A variety of possible syntheses of the two theoretical modes are therefore explored, in the belief that the most comprehensive account of delusions will involve a theoretical unification of both styles of explanation. Along the way, an attempt is made to locate the notions delusion, defence, and self-deception in a shared theoretical space. PMID:16571464

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

    PubMed

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

    2015-11-01

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

  6. Faba bean forisomes can function in defence against generalist aphids.

    PubMed

    Medina-Ortega, Karla J; Walker, Gregory P

    2015-06-01

    Phloem sieve elements have shut-off mechanisms that prevent loss of nutrient-rich phloem sap when the phloem is damaged. Some phloem proteins such as the proteins that form forisomes in legume sieve elements are one such mechanism and in response to damage, they instantly form occlusions that stop the flow of sap. It has long been hypothesized that one function of phloem proteins is defence against phloem sap-feeding insects such as aphids. This study provides the first experimental evidence that aphid feeding can induce phloem protein occlusion and that the aphid-induced occlusions inhibit phloem sap ingestion. The great majority of phloem penetrations in Vicia faba by the generalist aphids Myzus persicae and Macrosiphum euphorbiae triggered forisome occlusion and the aphids eventually withdrew their stylets without ingesting phloem sap. This contrasts starkly with a previous study on the legume-specialist aphid, Acyrthosiphon pisum, where penetration of faba bean sieve elements did not trigger forisome occlusion and the aphids readily ingested phloem sap. Next, forisome occlusion was demonstrated to be the cause of failed phloem ingestion attempts by M. persicae: when occlusion was inhibited by the calcium channel blocker lanthanum, M. persicae readily ingested faba bean phloem sap.

  7. Psychic skin: psychotic defences, borderline process and delusions.

    PubMed

    Schmidt, Martin

    2012-02-01

    In this paper, I apply the concept of psychic skin to analytic work with people suffering from personality disorders and psychoses. When psychoses emerge, the defensive skin which protects the ego is breached and violent unconscious forces rip through the personality. Some of the patients diagnosed as schizophrenic with whom I work have identified with archetypal characters such as Christ, Satan, John Lennon and the Queen. I attempt to show how the adoption of these inflated personas can serve as secondary psychic skins. Such delusional identifications can provide a protective shield to hide the denuded self and prevent intrusion from the external world. Through clinical example, I try to demonstrate how these archetypal 'second skins' can preserve life until internal and external conditions make it possible for the self to emerge. I contrast such psychotic identifications with 'thin-skinned' and 'thick-skinned' narcissism as well as 'defences of the self' in borderline states where the psychic skin may be damaged but does not disintegrate. I also look at the ways in which Jung's own personal experience was different from this and how he managed to avert psychotic breakdown. PMID:22288539

  8. Symbiotic bacteria enable olive fly larvae to overcome host defences.

    PubMed

    Ben-Yosef, Michael; Pasternak, Zohar; Jurkevitch, Edouard; Yuval, Boaz

    2015-07-01

    Ripe fruit offer readily available nutrients for many animals, including fruit fly larvae (Diptera: Tephritidae) and their associated rot-inducing bacteria. Yet, during most of their ontogeny, fruit remain chemically defended and effectively suppress herbivores and pathogens by high levels of secondary metabolites. Olive flies (Bactrocera oleae) are uniquely able to develop in unripe olives. Unlike other frugivorous tephritids, the larvae maintain bacteria confined within their midgut caeca. We examined the interaction between larvae, their associated bacteria, and fruit chemical defence, hypothesizing that bacterial contribution to larval development is contingent on the phenology of fruit defensive chemistry. We demonstrate that larvae require their natural complement of bacteria (Candidatus Erwinia dacicola: Enterobacteriaceae) in order to develop in unripe olives. Conversely, when feeding on ripe fruit, larval development proceeds independently of these bacteria. Our experiments suggest that bacteria counteract the inhibitory effect of oleuropein-the principal phenolic glycoside in unripe olives. In light of these results, we suggest that the unique symbiosis in olive flies, compared with other frugivorous tephritids, is understood by considering the relationship between the fly, bacteria and fruit chemistry. When applied in an evolutionary context, this approach may also point out the forces which shaped symbioses across the Tephritidae.

  9. An overview of the Defence Research Agency photovoltaic programme

    NASA Technical Reports Server (NTRS)

    Goodbody, C.; Davies, M. A. H.

    1993-01-01

    The Defense Research Agency (DRA) has been active in the photovoltaic field since the early 1960's, then as the Royal Aircraft Establishment (RAE). The early work was aimed at developing silicon cells, solar panels, and light-weight flexible arrays in support of the 'UK' and 'X' series of British scientific and technology satellites, for which the RAE was either the design authority or technical advisor. The X3 satellite - Prospero, launched in 1971 test flew 50 micron wrap-round silicon cells. The X4 satellite - Miranda, launched in 1974 test flew a deployable flexible silicon array which was developed at the DRA. During this period an extensive range of test equipment was developed which was maintained, modernized, and extended to date. Following a period of reduced activity in the late 1970's and early 1980's the current program evolved. The programs that have been undertaken since 1983 are briefly summarized. These range from various cell developments, new types of coverglasses, flight experiments, radiation testing, primary cell calibration, and environmental testing. The current photovoltaic program is mainly funded by the UK Ministry of Defence and by the Department of Trade and Industry through the British National Space Center (BNSC). The program is aimed at research and development, both internally and with industry, to meet the customer's technical objectives and requirements and to provide them with technical advice. The facilities are also being used on contract work for various national and international organizations.

  10. PLANT OLIGOSACCHARIDES ENHANCE WHEAT DEFENCE RESPONSE AGAINST SEPTORIA LEAF BLOTCH.

    PubMed

    Somai-Jemmali, L; Siah, A; Randoux, B; Reignault, Ph; Halama, P; Rodriguez, R; Hamada, W

    2015-01-01

    Our work provides the first evidence for elicitation and protection effects of preventive treatments with oligosaccharides (20%)-based new formulation (Oligos) against Mycosphaerella graminicola, a major pathogen of bread wheat (BW) and durum wheat (DW). In planta Oligos treatment led to strongly reduced hyphal growth, penetration, mesophyll colonization and fructification. During the necrotrophic phase, Oligos also drastically decreased the production of M. graminicola CWDE activities, such as xylanase and glucanase as well as protease activity in both wheat species, suggesting their correlation with disease severity. Concerning plant defence markers, PR2, Chi 4 precursor-, Per- and LOX-1-encoding genes were up-regulated, while glucanase (GLUC), catalase (CAT) and lipoxygenase (LOX) activities and total phenolic compound (PC) accumulation were induced in both (non-inoculated and inoculated contexts. In inoculated context, a localized accumulation of H2O2 and PC at fungal penetration sites and a specific induction of phenylalanine ammonia-Lyase (PAL) enzymatic activity were observed. Moreover, our experiment exhibited some similarities and differences in both wheat species responses. GLUC and CAT activities and H2O2 accumulation were more responsive in DW leaves, while LOX and PAL activities and PC accumulation occurred earlier and to a stronger extent in BW leaves. The tested Oligos formulation showed an interesting resistance induction activity characterized by a high and stable efficiency whatever the wheat species, suggesting it integration in common control strategies against STB on both DW and BW. PMID:27141743

  11. Thermal Imaging And Its Application In Defence Systems

    NASA Astrophysics Data System (ADS)

    Akula, Aparna; Ghosh, Ripul; Sardana, H. K.

    2011-10-01

    Thermal imaging is a boon to the armed forces namely army, navy and airforce because of its day night working capability and ability to perform well in all weather conditions. Thermal detectors capture the infrared radiation emitted by all objects above absolute zero temperature. The temperature variations of the captured scene are represented as a thermogram. With the advent of infrared detector technology, the bulky cooled thermal detectors having moving parts and demanding cryogenic temperatures have transformed into small and less expensive uncooled microbolometers having no moving parts, thereby making systems more rugged requiring less maintenance. Thermal imaging due to its various advantages has a large number of applications in military and defence. It is popularly used by the army and navy for border surveillance and law enforcement. It is also used in ship collision avoidance and guidance systems. In the aviation industry it has greatly mitigated the risks of flying in low light and night conditions. They are widely used in military aviation to identify, locate and target the enemy forces. Recently, they are also being incorporated in civil aviation for health monitoring of aircrafts.

  12. A transcriptional reference map of defence hormone responses in potato

    PubMed Central

    Wiesel, Lea; Davis, Jayne L.; Milne, Linda; Redondo Fernandez, Vanesa; Herold, Miriam B.; Middlefell Williams, Jill; Morris, Jenny; Hedley, Pete E.; Harrower, Brian; Newton, Adrian C.; Birch, Paul R. J.; Gilroy, Eleanor M.; Hein, Ingo

    2015-01-01

    Phytohormones are involved in diverse aspects of plant life including the regulation of plant growth, development and reproduction, as well as governing biotic and abiotic stress responses. We have generated a comprehensive transcriptional reference map of the early potato responses to exogenous application of the defence hormones abscisic acid, brassinolides (applied as epibrassinolide), ethylene (applied as the ethylene precursor aminocyclopropanecarboxylic acid), salicylic acid and jasmonic acid (applied as methyl jasmonate). Of the 39000 predicted genes on the microarray, a total of 2677 and 2473 genes were significantly differentially expressed at 1 h and 6 h after hormone treatment, respectively. Specific marker genes newly identified for the early hormone responses in potato include: a homeodomain 20 transcription factor (DMG400000248) for abscisic acid; a SAUR gene (DMG400016561) induced in epibrassinolide treated plants; an osmotin gene (DMG400003057) specifically enhanced by aminocyclopropanecarboxylic acid; a gene weakly similar to AtWRKY40 (DMG402007388) that was induced by salicylic acid; and a jasmonate ZIM-domain protein 1 (DMG400002930) which was specifically activated by methyl jasmonate. An online database has been set up to query the expression patterns of potato genes represented on the microarray that can also incorporate future microarray or RNAseq-based expression studies. PMID:26477733

  13. Trade-off among different anti-herbivore defence strategies along an altitudinal gradient.

    PubMed

    Dostálek, Tomáš; Rokaya, Maan Bahadur; Maršík, Petr; Rezek, Jan; Skuhrovec, Jiří; Pavela, Roman; Münzbergová, Zuzana

    2016-01-01

    The type and intensity of plant-herbivore interactions are likely to be altered under climate change as a consequence of differential dispersal rates of plants and their herbivores. Here, we studied variation in herbivore damage on Salvia nubicola in the field and compared its growth and defence strategies against herbivores in controlled conditions using seeds from populations along a broad altitudinal gradient. Our work is one of the first studies to simultaneously measure complex intraspecific variation in plant growth, direct and indirect defences as well as plant tolerance (ability to regrow) as a consequence of herbivore attack simulated by clipping. In the field, we found that plants experienced higher herbivore pressure in lower altitudes. In the greenhouse, plants grown from seeds collected in lower-altitude populations grew better and produced a higher content of phenolic compounds (direct defence) and volatile organic compounds (indirect defence) in response to simulated herbivory. However, there were no differences in tolerance and effect of S. nubicola extracts on the model generalist herbivore Spodoptera littoralis (direct defence) along the altitudinal gradient. Although we found that S. nubicola developed a range of defence strategies, the strategies do not seem to be used simultaneously in all populations even though most of them are correlated with altitudinal gradient. Our finding is in agreement with the current knowledge that co-expression of multiple defences might be costly for a plant, since investment in defensive traits is assumed to reduce the resource availability for growth and reproduction. Our study thus shows the importance of simultaneous study of different defence strategies since understanding these trade-offs could be necessary for detecting the mechanisms by which plants are able to cope with future climate change. PMID:27169609

  14. Trade-off among different anti-herbivore defence strategies along an altitudinal gradient

    PubMed Central

    Dostálek, Tomáš; Rokaya, Maan Bahadur; Maršík, Petr; Rezek, Jan; Skuhrovec, Jiří; Pavela, Roman; Münzbergová, Zuzana

    2016-01-01

    The type and intensity of plant–herbivore interactions are likely to be altered under climate change as a consequence of differential dispersal rates of plants and their herbivores. Here, we studied variation in herbivore damage on Salvia nubicola in the field and compared its growth and defence strategies against herbivores in controlled conditions using seeds from populations along a broad altitudinal gradient. Our work is one of the first studies to simultaneously measure complex intraspecific variation in plant growth, direct and indirect defences as well as plant tolerance (ability to regrow) as a consequence of herbivore attack simulated by clipping. In the field, we found that plants experienced higher herbivore pressure in lower altitudes. In the greenhouse, plants grown from seeds collected in lower-altitude populations grew better and produced a higher content of phenolic compounds (direct defence) and volatile organic compounds (indirect defence) in response to simulated herbivory. However, there were no differences in tolerance and effect of S. nubicola extracts on the model generalist herbivore Spodoptera littoralis (direct defence) along the altitudinal gradient. Although we found that S. nubicola developed a range of defence strategies, the strategies do not seem to be used simultaneously in all populations even though most of them are correlated with altitudinal gradient. Our finding is in agreement with the current knowledge that co-expression of multiple defences might be costly for a plant, since investment in defensive traits is assumed to reduce the resource availability for growth and reproduction. Our study thus shows the importance of simultaneous study of different defence strategies since understanding these trade-offs could be necessary for detecting the mechanisms by which plants are able to cope with future climate change. PMID:27169609

  15. Contrasting ontogenetic trajectories for phenolic and terpenoid defences in Eucalyptus froggattii

    PubMed Central

    Goodger, Jason Q. D.; Heskes, Allison M.; Woodrow, Ian E.

    2013-01-01

    Background and Aims Plant defence metabolites are considered costly due to diversion of energy and nutrients away from growth. These costs combined with changes in resource availability and herbivory throughout plant ontogeny are likely to promote changes in defence metabolites. A comprehensive understanding of plant defence strategy requires measurement of lifetime ontogenetic trajectories – a dynamic component largely overlooked in plant defence theories. This study aimed to compare ontogenetic trajectories of foliar phenolics and terpenoids. Phenolics are predicted to be inexpensive to biosynthesize, whereas expensive terpenoids also require specialized, non-photosynthetic secretory structures to avoid autotoxicity. Based on these predicted costs, it is hypothesized that phenolics would be maximally deployed early in ontogeny, whereas terpenoids would be maximally deployed later, once the costs of biosynthesis and foregone photosynthesis could be overcome by enhanced resource acquisition. Methods Leaves were harvested from a family of glasshouse-grown Eucalyptus froggattii seedlings, field-grown saplings and the maternal parent tree, and analysed for total terpenoids and phenolics. Key Results Foliar phenolics were highest in young seedlings and lowest in the adult tree. Indeed the ratio of total phenolics to total terpenoids decreased in a significantly exponential manner with plant ontogeny. Most individual terpene constituents increased with plant ontogeny, but some mono- and sesquiterpenes remained relatively constant or even decreased in concentration as plants aged. Conclusions Plant ontogeny can influence different foliar defence metabolites in directionally opposite ways, and the contrasting trajectories support our hypothesis that phenolics would be maximally deployed earlier than terpenoids. The results highlight the importance of examining ontogenetic trajectories of defence traits when developing and testing theories of plant defence, and

  16. Hijacking common mycorrhizal networks for herbivore-induced defence signal transfer between tomato plants

    PubMed Central

    Song, Yuan Yuan; Ye, Mao; Li, Chuanyou; He, Xinhua; Zhu-Salzman, Keyan; Wang, Rui Long; Su, Yi Juan; Luo, Shi Ming; Zeng, Ren Sen

    2014-01-01

    Common mycorrhizal networks (CMNs) link multiple plants together. We hypothesized that CMNs can serve as an underground conduit for transferring herbivore-induced defence signals. We established CMN between two tomato plants in pots with mycorrhizal fungus Funneliformis mosseae, challenged a ‘donor' plant with caterpillar Spodoptera litura, and investigated defence responses and insect resistance in neighbouring CMN-connected ‘receiver' plants. After CMN establishment caterpillar infestation on ‘donor' plant led to increased insect resistance and activities of putative defensive enzymes, induction of defence-related genes and activation of jasmonate (JA) pathway in the ‘receiver' plant. However, use of a JA biosynthesis defective mutant spr2 as ‘donor' plants resulted in no induction of defence responses and no change in insect resistance in ‘receiver' plants, suggesting that JA signalling is required for CMN-mediated interplant communication. These results indicate that plants are able to hijack CMNs for herbivore-induced defence signal transfer and interplant defence communication. PMID:24468912

  17. Competition induces allelopathy but suppresses growth and anti-herbivore defence in a chemically rich seaweed

    PubMed Central

    Rasher, Douglas B.; Hay, Mark E.

    2014-01-01

    Many seaweeds and terrestrial plants induce chemical defences in response to herbivory, but whether they induce chemical defences against competitors (allelopathy) remains poorly understood. We evaluated whether two tropical seaweeds induce allelopathy in response to competition with a reef-building coral. We also assessed the effects of competition on seaweed growth and seaweed chemical defence against herbivores. Following 8 days of competition with the coral Porites cylindrica, the chemically rich seaweed Galaxaura filamentosa induced increased allelochemicals and became nearly twice as damaging to the coral. However, it also experienced significantly reduced growth and increased palatability to herbivores (because of reduced chemical defences). Under the same conditions, the seaweed Sargassum polycystum did not induce allelopathy and did not experience a change in growth or palatability. This is the first demonstration of induced allelopathy in a seaweed, or of competitors reducing seaweed chemical defences against herbivores. Our results suggest that the chemical ecology of coral–seaweed–herbivore interactions can be complex and nuanced, highlighting the need to incorporate greater ecological complexity into the study of chemical defence. PMID:24403332

  18. Parental risk management in relation to offspring defence: bad news for kids

    PubMed Central

    Mahr, Katharina; Riegler, Georg; Hoi, Herbert

    2015-01-01

    Do parents defend their offspring whenever necessary, and do self-sacrificing parents really exist? Studies recognized that parent defence is dynamic, mainly depending on the threat predators pose. In this context, parental risk management should consider the threat to themselves and to their offspring. Consequently, the observed defence should be a composite of both risk components. Surprisingly, no study so far has determined the influence of these two threat components on parental decision rules. In a field experiment, we investigated parental risk taking in relation to the threat posed to themselves and their offspring. To disentangle the two threat components, we examined defence behaviours of parent blue tits Cyanistes caeruleus towards three different predators and during different nestling developmental stages. Nest defence strategies in terms of alarm call intensity and nearest predator approach differed between the three predators. Defence intensity was only partly explained by threat level. Most importantly, parental risk management varied in relation to their own, but not offspring risk. Parent defence investment was independent of nestling risk when parents followed a high-risk strategy. However, parents considered nestling as well as parental risk when following a low-risk strategy. Our findings could have general implications for the economy of risk management and decision-making strategies in living beings, including humans. PMID:25392467

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

    PubMed

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

    2012-04-23

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

  20. Competition induces allelopathy but suppresses growth and anti-herbivore defence in a chemically rich seaweed.

    PubMed

    Rasher, Douglas B; Hay, Mark E

    2014-02-22

    Many seaweeds and terrestrial plants induce chemical defences in response to herbivory, but whether they induce chemical defences against competitors (allelopathy) remains poorly understood. We evaluated whether two tropical seaweeds induce allelopathy in response to competition with a reef-building coral. We also assessed the effects of competition on seaweed growth and seaweed chemical defence against herbivores. Following 8 days of competition with the coral Porites cylindrica, the chemically rich seaweed Galaxaura filamentosa induced increased allelochemicals and became nearly twice as damaging to the coral. However, it also experienced significantly reduced growth and increased palatability to herbivores (because of reduced chemical defences). Under the same conditions, the seaweed Sargassum polycystum did not induce allelopathy and did not experience a change in growth or palatability. This is the first demonstration of induced allelopathy in a seaweed, or of competitors reducing seaweed chemical defences against herbivores. Our results suggest that the chemical ecology of coral-seaweed-herbivore interactions can be complex and nuanced, highlighting the need to incorporate greater ecological complexity into the study of chemical defence. PMID:24403332

  1. Uncoupling of reactive oxygen species accumulation and defence signalling in the metal hyperaccumulator plant Noccaea caerulescens.

    PubMed

    Fones, Helen N; Eyles, Chris J; Bennett, Mark H; Smith, J Andrew C; Preston, Gail M

    2013-09-01

    The metal hyperaccumulator plant Noccaea caerulescens is protected from disease by the accumulation of high concentrations of metals in its aerial tissues, which are toxic to many pathogens. As these metals can lead to the production of damaging reactive oxygen species (ROS), metal hyperaccumulator plants have developed highly effective ROS tolerance mechanisms, which might quench ROS-based signals. We therefore investigated whether metal accumulation alters defence signalling via ROS in this plant. We studied the effect of zinc (Zn) accumulation by N. caerulescens on pathogen-induced ROS production, salicylic acid accumulation and downstream defence responses, such as callose deposition and pathogenesis-related (PR) gene expression, to the bacterial pathogen Pseudomonas syringae pv. maculicola. The accumulation of Zn caused increased superoxide production in N. caerulescens, but inoculation with P. syringae did not elicit the defensive oxidative burst typical of most plants. Defences dependent on signalling through ROS (callose and PR gene expression) were also modified or absent in N. caerulescens, whereas salicylic acid production in response to infection was retained. These observations suggest that metal hyperaccumulation is incompatible with defence signalling through ROS and that, as metal hyperaccumulation became effective as a form of elemental defence, normal defence responses became progressively uncoupled from ROS signalling in N. caerulescens. PMID:23758201

  2. Fiber Bragg Grating Temperature Sensor for Defence and Industrial Applications

    NASA Astrophysics Data System (ADS)

    Gebru, Haftay Abadi; Padhy, B. B.

    2011-10-01

    This paper presents the design and development of fiber Bragg grating (FBG) temperature sensor suitable for naval applications like temperature monitoring of onboard ships. The Bragg gratings used here have a reflection Bragg wavelength of 1550 nm and are inscribed by phase mask technique using ultraviolet (UV) laser beam at 255.3 nm. The high-resolution temperature sensor has been designed and developed based on the principle of converting the strain to temperature. This is achieved by using bimetallic configuration. Here lead and tungsten metals are used. The expansion of lead is concentrated on the Bragg grating, thus imparting strain on it. The wavelength shift with change of temperature is recorded with optical spectrum analyzer. The minimum temperature that could be measured accurately by the sensor with repeatability is of the order of 10-2. We have achieved thermal sensitivity of 46 pm/°C and 72 pm/°C for sensor lengths (length of the metallic strips) of 60 mm and 100 mm respectively. The thermal sensitivity achieved is approximately 3.5 times and 5.5 times that of bare FBG with thermal sensitivity of 13 pm/°C for the respective sensor lengths. This type of sensor can play vital role in defence and industrial applications like monitoring fresh water/lubricating oil temperatures of machinery in onboard ships, temperature monitoring of airframe of the aircraft, aircraft engine control system sensors, temperature measurement of hot gases from propellant combustion to protect the rocket motor casing, monitoring and control of temperature of copper bars of the power generators etc.

  3. Neisseria meningitidis, pathogenetic mechanisms to overcome the human immune defences.

    PubMed

    Gasparini, R; Amicizia, D; Lai, P L; Panatto, D

    2012-06-01

    Neisseria meningitidis is hosted only by humans and colonizes the nasopharynx; it survives in the human body by reaching an equilibrium with its exclusive host. Indeed, while cases of invasive disease are rare, the number of asymptomatic Neisseria meningitides carriers is far higher. The aim of this paper is to summarize the current knowledge of survival strategies of Neisseria meningitides against the human immune defences. Neisseria meningitidis possesses a variety of adaptive characteristics which enable it to avoid being killed by the immune system, such as the capsule, the lipopolysaccharide, groups of proteins that block the action of the antimicrobial proteins (AMP), proteins that inhibit the complement system, and components that prevent both the maturation and the perfect functioning of phagocytes. The main means of adhesion of Neisseria meningitides to the host cells are Pili, constituted by several proteins of whom the most important is Pilin E. Opacity-associated proteins (Opa) and (Opc) are two proteins that make an important contribution to the process of adhesion to the cell. Porins A and B contribute to neisserial adhesion and penetration into the cells, and also inhibit the complement system. Factor H binding protein (fhbp) binds factor H, allowing the bacteria to survive in the blood. Neisserial adhesin A (NadA) is a minor adhesin that is expressed by 50% of the pathogenic strains. NadA is known to be involved in cell adhesion and invasion and in the induction of proinflammatory cytokines. Neisserial heparin binding antigen (NHBA) binds heparin, thus increasing the resistance of the bacterium in the serum.

  4. Lichen palatability depends on investments in herbivore defence.

    PubMed

    Gauslaa, Yngvar

    2005-03-01

    Lichens are well-suited organisms for experimental herbivory studies because their secondary compounds, assumed to deter grazing, can be non-destructively extracted. Thalli of 17 lichen species from various habitats were cut in two equal parts; compounds were extracted from one part by acetone, the other served as a control. These two pieces were offered as a paired choice to the generalist herbivore snail Cepaea hortensis. Control thalli of all lichens were consumed at a low rate regardless of their investments in acetone-extractable lichen compounds; naturally compound-deficient lichen species were not preferred compared to those with high contents. However, for extracted thalli, there was a highly significant positive correlation between rate of consumption and the extracted compound contents. These data imply that herbivore defence has evolved in different directions in different lichens. Studied members of Parmeliaceae, common in oligotrophic habitats, have high contents of carbon-rich acetone-soluble compounds; these lichens became highly palatable to snails subsequent to acetone rinsing. Extracted lichen compounds were applied to pieces of filter paper and fed to snails. Extracts from members of the Parmeliaceae significantly deterred feeding on paper. Such data suggest that generalist herbivores may have shaped evolution in the widespread and highly diverse Parmeliaceae towards high investments in lichen compounds. On the other hand, lichens belonging to the Physciaceae and Teloschistales, common in nutrient-enriched habitats, are deficient in, or have low concentrations of, lichen compounds. Such lichens did not become more palatable after acetone rinsing. The orange anthraquinone compound parietin, restricted to the Teloschistales, and which has previously been found to protect against excess light, did not deter grazing.

  5. Evolution of behavioural and cellular defences against parasitoid wasps in the Drosophila melanogaster subgroup.

    PubMed

    Lynch, Z R; Schlenke, T A; de Roode, J C

    2016-05-01

    It may be intuitive to predict that host immune systems will evolve to counter a broad range of potential challenges through simultaneous investment in multiple defences. However, this would require diversion of resources from other traits, such as growth, survival and fecundity. Therefore, ecological immunology theory predicts that hosts will specialize in only a subset of possible defences. We tested this hypothesis through a comparative study of a cellular immune response and a putative behavioural defence used by eight fruit fly species against two parasitoid wasp species (one generalist and one specialist). Fly larvae can survive infection by melanotically encapsulating wasp eggs, and female flies can potentially reduce infection rates in their offspring by laying fewer eggs when wasps are present. The strengths of both defences varied significantly but were not negatively correlated across our chosen host species; thus, we found no evidence for a trade-off between behavioural and cellular immunity. Instead, cellular defences were significantly weaker against the generalist wasp, whereas behavioural defences were similar in strength against both wasps and positively correlated between wasps. We investigated the adaptive significance of wasp-induced oviposition reduction behaviour by testing whether wasp-exposed parents produce offspring with stronger cellular defences, but we found no support for this hypothesis. We further investigated the sensory basis of this behaviour by testing mutants deficient in either vision or olfaction, both of which failed to reduce their oviposition rates in the presence of wasps, suggesting that both senses are necessary for detecting and responding to wasps. PMID:26859227

  6. Predator-induced defences in Daphnia longicephala: location of kairomone receptors and timeline of sensitive phases to trait formation.

    PubMed

    Weiss, Linda C; Leimann, Julian; Tollrian, Ralph

    2015-09-01

    The freshwater crustacean Daphnia adapts to changing predation risks by forming inducible defences. These are only formed when they are advantageous, saving associated costs when the defence is superfluous. However, in order to be effective, the time lag between the onset of predation and the defence formation has to be short. Daphnia longicephala develop huge protective crests upon exposure to chemical cues (kairomones) from its predator the heteropteran backswimmer Notonecta glauca. To analyse time lags, we determined kairomone-sensitive stages and the developmental time frames of inducible defences. Moreover, we looked at additive effects that could result from the summation of prolonged kairomone exposure. Kairomones are perceived by chemoreceptors and integrated by the nervous system, which alters the developmental program leading to defence formation. The underlying neuronal and developmental pathways are not thoroughly described and surprisingly, the location of the kairomone receptors is undetermined. We show that D. longicephala start to sense predator cues at the onset of the second juvenile instar, defences develop with a time lag of one instar and prolonged kairomone exposure does not impact the magnitude of the defence. By establishing a method to reversibly impair chemosensors, we show the first antennae as the location of kairomone-detecting chemoreceptors. This study provides fundamental information on kairomone perception, kairomone-sensitive stages, developmental time frames and lag times of inducible defences in D. longicephala that will greatly contribute to the further understanding of the neuronal and developmental mechanisms of predator-induced defences in Daphnia.

  7. Predator-induced defences in Daphnia longicephala: location of kairomone receptors and timeline of sensitive phases to trait formation

    PubMed Central

    Weiss, Linda C.; Leimann, Julian; Tollrian, Ralph

    2015-01-01

    ABSTRACT The freshwater crustacean Daphnia adapts to changing predation risks by forming inducible defences. These are only formed when they are advantageous, saving associated costs when the defence is superfluous. However, in order to be effective, the time lag between the onset of predation and the defence formation has to be short. Daphnia longicephala develop huge protective crests upon exposure to chemical cues (kairomones) from its predator the heteropteran backswimmer Notonecta glauca. To analyse time lags, we determined kairomone-sensitive stages and the developmental time frames of inducible defences. Moreover, we looked at additive effects that could result from the summation of prolonged kairomone exposure. Kairomones are perceived by chemoreceptors and integrated by the nervous system, which alters the developmental program leading to defence formation. The underlying neuronal and developmental pathways are not thoroughly described and surprisingly, the location of the kairomone receptors is undetermined. We show that D. longicephala start to sense predator cues at the onset of the second juvenile instar, defences develop with a time lag of one instar and prolonged kairomone exposure does not impact the magnitude of the defence. By establishing a method to reversibly impair chemosensors, we show the first antennae as the location of kairomone-detecting chemoreceptors. This study provides fundamental information on kairomone perception, kairomone-sensitive stages, developmental time frames and lag times of inducible defences in D. longicephala that will greatly contribute to the further understanding of the neuronal and developmental mechanisms of predator-induced defences in Daphnia. PMID:26400980

  8. Priming of anti-herbivore defence in Nicotiana attenuata by insect oviposition: herbivore-specific effects.

    PubMed

    Bandoly, Michele; Grichnik, Roland; Hilker, Monika; Steppuhn, Anke

    2016-04-01

    Oviposition by Spodoptera exigua on Nicotiana attenuata primes plant defence against its larvae that consequently suffer reduced performance. To reveal whether this is a general response of tobacco to insect oviposition or species-specific, we investigated whether also Manduca sexta oviposition primes N. attenuata's anti-herbivore defence. The plant response to M. sexta and S. exigua oviposition overlapped in the egg-primed feeding-induced production of the phenylpropanoid caffeoylputrescine. While M. sexta larvae were unaffected in their performance, they showed a novel response to the oviposition-mediated plant changes: a reduced antimicrobial activity in their haemolymph. In a cross-resistance experiment, S. exigua larvae suffered reduced performance on M. sexta-oviposited plants like they did on S. exigua-oviposited plants. The M. sexta oviposition-mediated plant effects on the S. exigua larval performance and on M. sexta larval immunity required expression of the NaMyb8 transcription factor that is governing biosynthesis of phenylpropanoids such as caffeoylputrescine. Thus, NaMyb8-dependent defence traits mediate the effects that oviposition by both lepidopteran species exerts on the plant's anti-herbivore defence. These results suggest that oviposition by lepidopteran species on N. attenuata leaves may generally prime the feeding-induced production of certain plant defence compounds but that different herbivore species show different susceptibility to egg-primed plant effects. PMID:26566692

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

    PubMed

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

    2013-04-01

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

  10. An inducible morphological defence is a passive by-product of behaviour in a marine snail

    PubMed Central

    Bourdeau, Paul E.

    2010-01-01

    Many organisms have evolved inducible defences in response to spatial and temporal variability in predation risk. These defences are assumed to incur large costs to prey; however, few studies have investigated the mechanisms and costs underlying these adaptive responses. I examined the proximate cause of predator-induced shell thickening in a marine snail (Nucella lamellosa) and tested whether induced thickening leads to an increase in structural strength. Results indicate that although predators (crabs) induce thicker shells, the response is a passive by-product of reduced feeding and somatic growth rather than an active physiological response to predation risk. Physical tests indicate that although the shells of predator-induced snails are significantly stronger, the increase in performance is no different than that of snails with limited access to food. Increased shell strength is attributable to an increase in the energetically inexpensive microstructural layer rather than to material property changes in the shell. This mechanism suggests that predator-induced shell defences may be neither energetically nor developmentally costly. Positive correlations between antipredator behaviour and morphological defences may explain commonly observed associations between growth reduction and defence production in other systems and could have implications for the evolutionary potential of these plastic traits. PMID:19846462

  11. "New Sport" in the street: self-defence, security and space in belle epoque Paris.

    PubMed

    Freundschuh, Aaron

    2006-01-01

    Near the turn of the twentieth century, traditional self-defence methods (for example, jiu-jitsu) were revamped into a more accessible and practical set of techniques and tactics for everyday use in urban public space. Framed as a "new sport" with broad public utility, early urban self-defence developed against the backdrop of heightening fears of violent crime and a burgeoning politics of security, as well as tensions provoked by the increasingly common appearance of unchaperoned, middle-class women in public. Self-defence masters pitched their innovations in an inclusive rhetoric, always with separate lessons for men and women and their respective spaces of risk. This article places modern self-defence practices in tension with historical transformations in the urban landscape, arguing that urban self-defence posited a certain subjective relation to the city that tapped simultaneously into the desire for empowerment, fantasies of criminal danger and a law-and-order tone that shaded into urban vigilantism. PMID:20737722

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

    PubMed Central

    Wilkins, Lucas; Osorio, Daniel; Hartley, Susan E.

    2015-01-01

    Leaf colour has been proposed to signal levels of host defence to insect herbivores, but we lack data on herbivory, leaf colour and levels of defence for wild host populations necessary to test this hypothesis. Such a test requires measurements of leaf spectra as they would be sensed by herbivore visual systems, as well as simultaneous measurements of chemical defences and herbivore responses to leaf colour in natural host-herbivore populations. In a large-scale field survey of wild cabbage (Brassica oleracea) populations, we show that variation in leaf colour and brightness, measured according to herbivore spectral sensitivities, predicts both levels of chemical defences (glucosinolates) and abundance of specialist lepidopteran (Pieris rapae) and hemipteran (Brevicoryne brassicae) herbivores. In subsequent experiments, P. rapae larvae achieved faster growth and greater pupal mass when feeding on plants with bluer leaves, which contained lower levels of aliphatic glucosinolates. Glucosinolate-mediated effects on larval performance may thus contribute to the association between P. rapae herbivory and leaf colour observed in the field. However, preference tests found no evidence that adult butterflies selected host plants based on leaf coloration. In the field, B. brassicae abundance varied with leaf brightness but greenhouse experiments were unable to identify any effects of brightness on aphid preference or performance. Our findings suggest that although leaf colour reflects both levels of host defences and herbivore abundance in the field, the ability of herbivores to respond to colour signals may be limited, even in species where performance is correlated with leaf colour. PMID:26353086

  13. Targeted predation of extrafloral nectaries by insects despite localized chemical defences.

    PubMed

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

    2015-10-01

    Extrafloral (EF) nectaries recruit carnivorous arthropods that protect plants from herbivory, but they can also be exploited by nectar thieves. We studied the opportunistic, targeted predation (and destruction) of EF nectaries by insects, and the localized chemical defences that plants presumably use to minimize this effect. In field and laboratory experiments, we identified insects that were possibly responsible for EF nectary predation in Vicia faba (fava bean) and determined the extent and accuracy of the feeding damage done to the EF nectaries by these insects. We also performed biochemical analyses of plant tissue samples in order to detect microscale distribution patterns of chemical defences in the area of the EF nectary. We observed selective, targeted feeding on EF nectaries by several insect species, including some that are otherwise not primarily herbivorous. Biochemical analyses revealed high concentrations of l-3,4-dihydroxyphenylalanine, a non-protein amino acid that is toxic to insects, near and within the EF nectaries. These results suggest that plants allocate defences to the protection of EF nectaries from predation, consistent with expectations of optimal defence theory, and that this may not be entirely effective, as insects limit their exposure to these defences by consuming only the secreting tissue of the nectary.

  14. Natural selection on quantitative immune defence traits: a comparison between theory and data.

    PubMed

    Seppälä, O

    2015-01-01

    Parasites present a threat for free-living species and affect several ecological and evolutionary processes. Immune defence is the main physiological barrier against infections, and understanding its evolution is central for predicting disease dynamics. I review theoretical predictions and empirical data on natural selection on quantitative immune defence traits in the wild. Evolutionary theory predicts immune traits to be under stabilizing selection owing to trade-offs between immune function and life-history traits. Empirical data, however, support mainly positive directional selection, but also show variation in the form of selection among study systems, immune traits and fitness components. I argue that the differences between theory and empirical data may at least partly arise from methodological difficulties in testing stabilizing selection as well as measuring fitness. I also argue that the commonness of positive directional selection and the variation in selection may be caused by several biological factors. First, selection on immune function may show spatial and temporal variation as epidemics are often local/seasonal. Second, factors affecting the range of phenotypic variation in immune traits could alter potential for selection. Third, different parasites may impose different selective pressures depending on their characteristics. Fourth, condition dependence of immune defence can obscure trade-offs related to it, thus possibly modifying observed selection gradients. Fifth, nonimmunological defences could affect the form of selection by reducing the benefits of strong immune function. To comprehensively understand the evolution of immune defence, the role of above factors should be considered in future studies.

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

    PubMed

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

    2015-01-01

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

  16. Rapid evolution of antioxidant defence in a natural population of Daphnia magna.

    PubMed

    Oexle, S; Jansen, M; Pauwels, K; Sommaruga, R; De Meester, L; Stoks, R

    2016-07-01

    Natural populations can cope with rapid changes in stressors by relying on sets of physiological defence mechanisms. Little is known onto what extent these physiological responses reflect plasticity and/or genetic adaptation, evolve in the same direction and result in an increased defence ability. Using resurrection ecology, we studied how a natural Daphnia magna population adjusted its antioxidant defence to ultraviolet radiation (UVR) during a period with increasing incident UVR reaching the water surface. We demonstrate a rapid evolution of the induction patterns of key antioxidant enzymes under UVR exposure in the laboratory. Notably, evolutionary changes strongly differed among enzymes and mainly involved the evolution of UV-induced plasticity. Whereas D. magna evolved a strong plastic up-regulation of glutathione peroxidase under UVR, it evolved a lower plastic up-regulation of glutathione S-transferase and superoxide dismutase and a plastic down-regulation of catalase. The differentially evolved antioxidant strategies were collectively equally effective in dealing with oxidative stress because they resulted in the same high levels of oxidative damage (to lipids, proteins and DNA) and lowered fitness (intrinsic growth rate) under UVR exposure. The lack of better protection against UVR may suggest that the UVR exposure did not increase between both periods. Predator-induced evolution to migrate to lower depths that occurred during the same period may have contributed to the evolved defence strategy. Our results highlight the need for a multiple trait approach when focusing on the evolution of defence mechanisms. PMID:27018861

  17. A herbivorous mite down-regulates plant defence and produces web to exclude competitors.

    PubMed

    Sarmento, Renato A; Lemos, Felipe; Dias, Cleide R; Kikuchi, Wagner T; Rodrigues, Jean C P; Pallini, Angelo; Sabelis, Maurice W; Janssen, Arne

    2011-01-01

    Herbivores may interact with each other through resource competition, but also through their impact on plant defence. We recently found that the spider mite Tetranychus evansi down-regulates plant defences in tomato plants, resulting in higher rates of oviposition and population growth on previously attacked than on unattacked leaves. The danger of such down-regulation is that attacked plants could become a more profitable resource for heterospecific competitors, such as the two-spotted spider mite Tetranychus urticae. Indeed, T. urticae had an almost 2-fold higher rate of oviposition on leaf discs on which T. evansi had fed previously. In contrast, induction of direct plant defences by T. urticae resulted in decreased oviposition by T. evansi. Hence, both herbivores affect each other through induced plant responses. However, when populations of T. evansi and T. urticae competed on the same plants, populations of the latter invariably went extinct, whereas T. evansi was not significantly affected by the presence of its competitor. This suggests that T. evansi can somehow prevent its competitor from benefiting from the down-regulated plant defence, perhaps by covering it with a profuse web. Indeed, we found that T. urticae had difficulties reaching the leaf surface to feed when the leaf was covered with web produced by T. evansi. Furthermore, T. evansi produced more web when exposed to damage or other cues associated with T. urticae. We suggest that the silken web produced by T. evansi serves to prevent competitors from profiting from down-regulated plant defences.

  18. Synergistic effects of direct and indirect defences on herbivore egg survival in a wild crucifer.

    PubMed

    Fatouros, Nina E; Pineda, Ana; Huigens, Martinus E; Broekgaarden, Colette; Shimwela, Methew M; Figueroa Candia, Ilich A; Verbaarschot, Patrick; Bukovinszky, Tibor

    2014-08-22

    Evolutionary theory of plant defences against herbivores predicts a trade-off between direct (anti-herbivore traits) and indirect defences (attraction of carnivores) when carnivore fitness is reduced. Such a trade-off is expected in plant species that kill herbivore eggs by exhibiting a hypersensitive response (HR)-like necrosis, which should then negatively affect carnivores. We used the black mustard (Brassica nigra) to investigate how this potentially lethal direct trait affects preferences and/or performances of specialist cabbage white butterflies (Pieris spp.), and their natural enemies, tiny egg parasitoid wasps (Trichogramma spp.). Both within and between black mustard populations, we observed variation in the expression of Pieris egg-induced HR. Butterfly eggs on plants with HR-like necrosis suffered lower hatching rates and higher parasitism than eggs that did not induce the trait. In addition, Trichogramma wasps were attracted to volatiles of egg-induced plants that also expressed HR, and this attraction depended on the Trichogramma strain used. Consequently, HR did not have a negative effect on egg parasitoid survival. We conclude that even within a system where plants deploy lethal direct defences, such defences may still act with indirect defences in a synergistic manner to reduce herbivore pressure. PMID:25009068

  19. Targeted predation of extrafloral nectaries by insects despite localized chemical defences.

    PubMed

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

    2015-10-01

    Extrafloral (EF) nectaries recruit carnivorous arthropods that protect plants from herbivory, but they can also be exploited by nectar thieves. We studied the opportunistic, targeted predation (and destruction) of EF nectaries by insects, and the localized chemical defences that plants presumably use to minimize this effect. In field and laboratory experiments, we identified insects that were possibly responsible for EF nectary predation in Vicia faba (fava bean) and determined the extent and accuracy of the feeding damage done to the EF nectaries by these insects. We also performed biochemical analyses of plant tissue samples in order to detect microscale distribution patterns of chemical defences in the area of the EF nectary. We observed selective, targeted feeding on EF nectaries by several insect species, including some that are otherwise not primarily herbivorous. Biochemical analyses revealed high concentrations of l-3,4-dihydroxyphenylalanine, a non-protein amino acid that is toxic to insects, near and within the EF nectaries. These results suggest that plants allocate defences to the protection of EF nectaries from predation, consistent with expectations of optimal defence theory, and that this may not be entirely effective, as insects limit their exposure to these defences by consuming only the secreting tissue of the nectary. PMID:26446809

  20. Synergistic effects of direct and indirect defences on herbivore egg survival in a wild crucifer

    PubMed Central

    Fatouros, Nina E.; Pineda, Ana; Huigens, Martinus E.; Broekgaarden, Colette; Shimwela, Methew M.; Figueroa Candia, Ilich A.; Verbaarschot, Patrick; Bukovinszky, Tibor

    2014-01-01

    Evolutionary theory of plant defences against herbivores predicts a trade-off between direct (anti-herbivore traits) and indirect defences (attraction of carnivores) when carnivore fitness is reduced. Such a trade-off is expected in plant species that kill herbivore eggs by exhibiting a hypersensitive response (HR)-like necrosis, which should then negatively affect carnivores. We used the black mustard (Brassica nigra) to investigate how this potentially lethal direct trait affects preferences and/or performances of specialist cabbage white butterflies (Pieris spp.), and their natural enemies, tiny egg parasitoid wasps (Trichogramma spp.). Both within and between black mustard populations, we observed variation in the expression of Pieris egg-induced HR. Butterfly eggs on plants with HR-like necrosis suffered lower hatching rates and higher parasitism than eggs that did not induce the trait. In addition, Trichogramma wasps were attracted to volatiles of egg-induced plants that also expressed HR, and this attraction depended on the Trichogramma strain used. Consequently, HR did not have a negative effect on egg parasitoid survival. We conclude that even within a system where plants deploy lethal direct defences, such defences may still act with indirect defences in a synergistic manner to reduce herbivore pressure. PMID:25009068

  1. Targeted predation of extrafloral nectaries by insects despite localized chemical defences

    PubMed Central

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

    2015-01-01

    Extrafloral (EF) nectaries recruit carnivorous arthropods that protect plants from herbivory, but they can also be exploited by nectar thieves. We studied the opportunistic, targeted predation (and destruction) of EF nectaries by insects, and the localized chemical defences that plants presumably use to minimize this effect. In field and laboratory experiments, we identified insects that were possibly responsible for EF nectary predation in Vicia faba (fava bean) and determined the extent and accuracy of the feeding damage done to the EF nectaries by these insects. We also performed biochemical analyses of plant tissue samples in order to detect microscale distribution patterns of chemical defences in the area of the EF nectary. We observed selective, targeted feeding on EF nectaries by several insect species, including some that are otherwise not primarily herbivorous. Biochemical analyses revealed high concentrations of l-3,4-dihydroxyphenylalanine, a non-protein amino acid that is toxic to insects, near and within the EF nectaries. These results suggest that plants allocate defences to the protection of EF nectaries from predation, consistent with expectations of optimal defence theory, and that this may not be entirely effective, as insects limit their exposure to these defences by consuming only the secreting tissue of the nectary. PMID:26446809

  2. A mathematical model of the defence mechanism of a bombardier beetle

    PubMed Central

    James, Alex; Morison, Ken; Todd, Simon

    2013-01-01

    Previous studies of bombardier beetles have shown that some species have a continuous discharge while others exhibit a pulsed discharge. Here, a mathematical model of the defence mechanism of the bombardier beetle is developed and the hypothesis that almost all bombardiers' defences have some sort of cyclic behaviour at frequencies much higher than previously thought is put forward. The observation of pulses arises from secondary lower frequency cycles that appear for some parameter values. For realistic parameter values, the model can exhibit all the characteristics seen in the various species of bombardier. The possibility that all bombardiers have the same underlying defence mechanism gives weight to the theory that all bombardiers' explosive secretory mechanisms have diversified from a common ancestral mechanism. PMID:23173197

  3. Overtopping failure analysis of coastal flood defences affected by climate change

    NASA Astrophysics Data System (ADS)

    Bahari Mehrabani, Mehrdad; Chen, Hua-Peng; Stevenson, Morris W.

    2015-07-01

    Sea defence structures are expected to protect coasts for a long period, hence requiring reliable performance assessment strategies, in order to ensure their integrity and functionality. It has been demonstrated that rising sea level together with changing wave height can lead to increase risks of the failure to coastal defence structures. This paper presents a method for assessing the risk of wave overtopping failure, analysing the joint probability of sea water level and significant wave height under future hydraulic conditions due to climate change. Monte Carlo simulations are utilised to analyse the time-dependant overtopping failure probability of a seawall in the UK subjected to sea level rise. The numerical results for the flood defence example show that the seawall subjected to the sea level rise with high emission scenario could face to a significant increase of the frequency and the rate of overtopping discharge in comparison with the present date conditions without consideration of seawall crest settlement.

  4. Can genetically based clines in plant defence explain greater herbivory at higher latitudes?

    PubMed

    Anstett, Daniel N; Ahern, Jeffrey R; Glinos, Julia; Nawar, Nabanita; Salminen, Juha-Pekka; Johnson, Marc T J

    2015-12-01

    Greater plant defence is predicted to evolve at lower latitudes in response to increased herbivore pressure. However, recent studies question the generality of this pattern. In this study, we tested for genetically based latitudinal clines in resistance to herbivores and underlying defence traits of Oenothera biennis. We grew plants from 137 populations from across the entire native range of O. biennis. Populations from lower latitudes showed greater resistance to multiple specialist and generalist herbivores. These patterns were associated with an increase in total phenolics at lower latitudes. A significant proportion of the phenolics were driven by the concentrations of two major ellagitannins, which exhibited opposing latitudinal clines. Our analyses suggest that these findings are unlikely to be explained by local adaptation of herbivore populations or genetic variation in phenology. Rather greater herbivory at high latitudes can be explained by latitudinal clines in the evolution of plant defences.

  5. Immigration of susceptible hosts triggers the evolution of alternative parasite defence strategies.

    PubMed

    Chabas, Hélène; van Houte, Stineke; Høyland-Kroghsbo, Nina Molin; Buckling, Angus; Westra, Edze R

    2016-08-31

    Migration of hosts and parasites can have a profound impact on host-parasite ecological and evolutionary interactions. Using the bacterium Pseudomonas aeruginosa UCBPP-PA14 and its phage DMS3vir, we here show that immigration of naive hosts into coevolving populations of hosts and parasites can influence the mechanistic basis underlying host defence evolution. Specifically, we found that at high levels of bacterial immigration, bacteria switched from clustered regularly interspaced short palindromic repeats (CRISPR-Cas) to surface modification-mediated defence. This effect emerges from an increase in the force of infection, which tips the balance from CRISPR to surface modification-based defence owing to the induced and fixed fitness costs associated with these mechanisms, respectively. PMID:27581884

  6. Voluntariness, intention, and the defence of mental disorder: toward a rational approach.

    PubMed

    McSherry, Bernadette

    2003-01-01

    This article addresses how mental disorder may be used in common law countries to negate the requirements of voluntariness and intention in serious criminal offences as well as to provide the basis for current versions of the insanity defence. The notion that mental disorder can cause conduct to become completely involuntary or unintentional is questionable, given current thinking in the behavioral sciences. This article argues that different forms of mental disorder should be subsumed within a separate defence of mental disorder. Providing that a range of dispositional options is available, the law in this complex area would be simplified and brought into line with current psychological notions of goal-directed behavior.

  7. Sentenced in sorrow: the role of asylum in the Jean Gianini murder defence.

    PubMed

    Gelb, S A

    1997-06-01

    This paper describes the role played by the notion of asylum in the legal battle over confessed murderer Jean Gianini's mental competence and commitment. Gianini was a 16 year old who murdered his former teacher in a small upstate New York town in 1914. His trial was the first in the US to employ the Binet-Simon intelligence test as a defence and featured a clash of expert witnesses whose credibility was based upon their residence and work in asylums. The verdict of 'not guilty due to criminal imbecility' was due to the defence team's successful portrayal of the asylum as a punishing prison from which the defendant would never be released.

  8. Interactions between nutritional approaches and defences against microbial diseases in small ruminants.

    PubMed

    Caroprese, M; Giannenas, I; Fthenakis, G C

    2015-12-14

    Objective of this review is to discuss the role of small ruminant diet in the defence of these animals against microbial diseases, in relation to different experimental approaches and various stressors acting on animals. The effects of various diets in immune reactions and animal defences are presented. Also, effects in relation to the species studied and the type of stressors acting on animals are discussed. Evidence is provided about the significance of the diet in enhancing immune responses of small ruminants during specific conditions, e.g., around parturition, during lactation, as well as in growing lambs or kids.

  9. Degradation of the plant defence hormone salicylic acid by the biotrophic fungus Ustilago maydis.

    PubMed

    Rabe, Franziska; Ajami-Rashidi, Ziba; Doehlemann, Gunther; Kahmann, Regine; Djamei, Armin

    2013-07-01

    Salicylic acid (SA) is a key plant defence hormone which plays an important role in local and systemic defence responses against biotrophic pathogens like the smut fungus Ustilago maydis. Here we identified Shy1, a cytoplasmic U. maydis salicylate hydroxylase which has orthologues in the closely related smuts Ustilago hordei and Sporisorium reilianum. shy1 is transcriptionally induced during the biotrophic stages of development but not required for virulence during seedling infection. Shy1 activity is needed for growth on plates with SA as a sole carbon source. The trigger for shy1 transcriptional induction is SA, suggesting the possibility of a SA sensing mechanism in this fungus.

  10. Sex-related differences in growth and carbon allocation to defence in Populus tremula as explained by current plant defence theories.

    PubMed

    Randriamanana, Tendry R; Nybakken, Line; Lavola, Anu; Aphalo, Pedro J; Nissinen, Katri; Julkunen-Tiitto, Riitta

    2014-05-01

    Plant defence theories have recently evolved in such a way that not only the quantity but also the quality of mineral nutrients is expected to influence plant constitutive defence. Recently, an extended prediction derived from the protein competition model (PCM) suggested that nitrogen (N) limitation is more important for the production of phenolic compounds than phosphorus (P). We aimed at studying sexual differences in the patterns of carbon allocation to growth and constitutive defence in relation to N and P availability in Populus tremula L. seedlings. We compared the gender responses in photosynthesis, growth and whole-plant allocation to phenolic compounds at different combination levels of N and P, and studied how they are explained by the main plant defence theories. We found no sexual differences in phenolic concentrations, but interestingly, slow-growing females had higher leaf N concentration than did males, and genders differed in their allocation priority. There was a trade-off between growth and the production of flavonoid-derived phenylpropanoids on one hand, and between the production of salicylates and flavonoid-derived phenylpropanoids on the other. Under limited nutrient conditions, females prioritized mineral nutrient acquisition, flavonoid and condensed tannin (CT) production, while males invested more in above-ground biomass. Salicylate accumulation followed the growth differentiation balance hypothesis as low N mainly decreased the production of leaf and stem salicylate content while the combination of both low N and low P increased the amount of flavonoids and CTs allocated to leaves and to a lesser extent stems, which agrees with the PCM. We suggest that such a discrepancy in the responses of salicylates and flavonoid-derived CTs is linked to their clearly distinct biosynthetic origins and/or their metabolic costs.

  11. Down-regulation of plant defence in a resident spider mite species and its effect upon con- and heterospecifics.

    PubMed

    Godinho, Diogo P; Janssen, Arne; Dias, Teresa; Cruz, Cristina; Magalhães, Sara

    2016-01-01

    Herbivorous spider mites occurring on tomato plants (Solanum lycopersicum L.) cope with plant defences in various manners: the invasive Tetranychus evansi reduces defences below constitutive levels, whereas several strains of T. urticae induce such defences and others suppress them. In the Mediterranean region, these two species co-occur on tomato plants with T. ludeni, another closely related spider mite species. Unravelling how this third mite species affects plant defences is thus fundamental to understanding the outcome of herbivore interactions in this system. To test the effect of T. ludeni on tomato plant defences, we measured (1) the activity of proteinase inhibitors, indicating the induction of plant defences, in those plants, and (2) mite performance on plants previously infested with each mite species. We show that the performance of T. evansi and T. ludeni on plants previously infested with T. ludeni or T. evansi was better than on clean plants, indicating that these two mite species down-regulate plant defences. We also show that plants attacked by these mite species had lower activity of proteinase inhibitors than clean plants, whereas herbivory by T. urticae increased the activity of these proteins and resulted in reduced spider mite performance. This study thus shows that the property of down-regulation of plant defences below constitutive levels also occurs in T. ludeni.

  12. Compact, diode-pumped, solid-state lasers for next generation defence and security sensors

    NASA Astrophysics Data System (ADS)

    Silver, M.; Lee, S. T.; Borthwick, A.; McRae, I.; Jackson, D.; Alexander, W.

    2015-06-01

    Low-cost semiconductor laser diode pump sources have made a dramatic impact in sectors such as advanced manufacturing. They are now disrupting other sectors, such as defence and security (D&S), where Thales UK is a manufacturer of sensor systems for application on land, sea, air and man portable. In this talk, we will first give an overview of the market trends and challenges in the D&S sector. Then we will illustrate how low cost pump diodes are enabling new directions in D&S sensors, by describing two diode pumped, solid- state laser products currently under development at Thales UK. The first is a new generation of Laser Target Designators (LTD) that are used to identify targets for the secure guiding of munitions. Current systems are bulky, expensive and require large battery packs to operate. The advent of low cost diode technology, merged with our novel solid-state laser design, has created a designator that will be the smallest, lowest cost, STANAG compatible laser designator on the market. The LTD delivers greater that 50mJ per pulse up to 20Hz, and has compact dimensions of 125×70×55mm. Secondly, we describe an ultra-compact, eye-safe, solid-state laser rangefinder (LRF) with reduced size, weight and power consumption compared to existing products. The LRF measures 100×55×34mm, weighs 200g, and can range to greater than 10km with a single laser shot and at a reprate of 1Hz. This also leverages off advances in laser pump diodes, but also utilises low cost, high reliability, packaging technology commonly found in the telecoms sector. As is common in the D&S sector, the products are designed to work in extreme environments, such as wide temperature range (-40 to +71°C) and high levels of shock and vibration. These disruptive products enable next- generation laser sensors such as rangefinders, target designators and active illuminated imagers.

  13. Air Pollution

    MedlinePlus

    Air pollution is a mixture of solid particles and gases in the air. Car emissions, chemicals from factories, ... Ozone, a gas, is a major part of air pollution in cities. When ozone forms air pollution, it's ...

  14. A non canonical subtilase attenuates the transcriptional activation of defence responses in Arabidopsis thaliana

    PubMed Central

    Serrano, Irene; Buscaill, Pierre; Audran, Corinne; Pouzet, Cécile; Jauneau, Alain; Rivas, Susana

    2016-01-01

    Proteases play crucial physiological functions in all organisms by controlling the lifetime of proteins. Here, we identified an atypical protease of the subtilase family [SBT5.2(b)] that attenuates the transcriptional activation of plant defence independently of its protease activity. The SBT5.2 gene produces two distinct transcripts encoding a canonical secreted subtilase [SBT5.2(a)] and an intracellular protein [SBT5.2(b)]. Concomitant to SBT5.2(a) downregulation, SBT5.2(b) expression is induced after bacterial inoculation. SBT5.2(b) localizes to endosomes where it interacts with and retains the defence-related transcription factor MYB30. Nuclear exclusion of MYB30 results in its reduced transcriptional activation and, thus, suppressed resistance. sbt5.2 mutants, with abolished SBT5.2(a) and SBT5.2(b) expression, display enhanced defence that is suppressed in a myb30 mutant background. Moreover, overexpression of SBT5.2(b), but not SBT5.2(a), in sbt5.2 plants reverts the phenotypes displayed by sbt5.2 mutants. Overall, we uncover a regulatory mode of the transcriptional activation of defence responses previously undescribed in eukaryotes. DOI: http://dx.doi.org/10.7554/eLife.19755.001 PMID:27685353

  15. Transcriptome analysis of genes involved in defence response in Polyporus umbellatus with Armillaria mellea infection

    PubMed Central

    Liu, Meng-Meng; Xing, Yong-Mei; Zhang, Da-Wei; Guo, Shun-Xing

    2015-01-01

    Polyporus umbellatus, a species symbiotic with Armillaria mellea and it also exhibits substantial defence response to Armillaria mellea infection. There are no genomics resources databases for understanding the molecular mechanism underlying the infection stress of P. umbellatus. Therefore, we performed a large-scale transcriptome sequencing of this fungus with A. mellea infection using Illumina sequencing technology. The assembly of the clean reads resulted in 120,576 transcripts, including 38,444 unigenes. Additionally, we performed a gene expression profiling analysis upon infection treatment. The results indicated significant differences in the gene expression profiles between the control and the infection group. In total, 10933 genes were identified between the two groups. Based on the differentially expressed genes, a Gene Ontology annotation analysis showed many defence-relevant categories. Meanwhile, the Kyoto Encyclopedia of Genes and Genomes pathway analysis uncovered some important pathways. Furthermore, the expression patterns of 13 putative genes that are involved in defence response resulting from quantitative real-time PCR were consistent with their transcript abundance changes as identified by RNA-seq. The sequenced genes covered a considerable proportion of the P. umbellatus transcriptome, and the expression results may be useful to strengthen the knowledge on the defence response of this fungus defend against Armillaria mellea invasion. PMID:26526032

  16. Avian predators taste-reject aposematic prey on the basis of their chemical defence.

    PubMed

    Skelhorn, John; Rowe, Candy

    2006-09-22

    Avian predators learn to avoid defended insects on the basis of their conspicuous warning coloration. In many aposematic species, the level of chemical defence varies, with some individuals being more defended than others. Sequestration and production of defence chemicals is often costly and therefore less defended individuals enjoy the benefits of the warning signal without paying the full costs of chemical production. This is a fundamental theoretical problem for the evolutionary stability of aposematism, since less defended individuals appear to be at a selective advantage. However, if predators sample aposematic prey and selectively reject individuals on the basis of their chemical investment, aposematism could become evolutionarily stable. Previous research aimed at testing whether birds can use taste to discriminate between palatable and unpalatable prey has been confounded by other experimental factors. Here, we show that birds can taste and reject prey entirely on the basis of an individual's level of chemical defence and more importantly, they can make decisions on whether or not to consume a defended individual based upon their level of chemical investment. We discuss these results in relation to the evolution of aposematism, mimicry and defence chemistry.

  17. Behavioural flexibility of the chemical defence in the parasitoid wasp Leptopilina heterotoma

    NASA Astrophysics Data System (ADS)

    Stökl, Johannes; Machacek, Zora; Ruther, Joachim

    2015-12-01

    Many insects use chemical defence mechanisms to defend themselves against predators. However, defensive secretions are costly to produce and should thus only be used in cases of real danger. This would require that insects are able to discriminate between predators to adjust their chemical defence. Here, we show that females of the parasitoid wasp Leptopilina heterotoma adjust the intensity of their chemical defence to differently sized predators. If attacked by Myrmica ants, the females always released their defensive secretion, which consists mainly of (-)-iridomyrmecin. However, if attacked by smaller Cardiocondyla ants, most females did not release any defensive spray, irrespective of the duration of the ant's aggression. When in contact with non-aggressive Nasonia wasps, the females of L. heterotoma did not release any defensive secretion. Our data show that females of L. heterotoma are able to discriminate between two predators and suggest that a predator of a certain size or strength is necessary to trigger the chemical defence mechanism of L. heterotoma.

  18. Inhibition of the baroreceptor reflex on stimulation in the brain stem defence centre

    PubMed Central

    Coote, J. H.; Hilton, S. M.; Perez-Gonzalez, J. F.

    1979-01-01

    1. In anaesthetized cats, the pattern of cardiovascular response characteristic of the defence reaction has been elicited by localized electrical stimulation within the appropriate region of the hypothalamus. The baroreceptor reflex response has been elicited by raising the pressure in a blind sac preparation of the carotid sinus or by electrical stimulation of the sinus nerve. 2. In addition to arterial blood pressure, heart rate and regional blood flows, activity was recorded in cardiac and renal sympathetic nerves, to assess more precisely the cardiomotor and vasomotor changes during interactions between brain stem stimulation and baroreceptor activation. 3. The sympatho-inhibitory and depressor effects of carotid sinus stimulation or electrical stimulation of the sinus nerve could be completely suppressed by stimulation within the hypothalamic defence area, as could the reflex bradycardia. It is concluded that this suppression is effected through the central nervous system. 4. Stimulation at points in the hypothalamus close to, but outside, the defence area, and which elicited increases in arterial pressure and sympathetic activity of similar magnitude to those from the defence area itself, did not abolish the sympatho-inhibitory or depressor effects of baroreceptor activation, though the reflex bradycardia was usually inhibited. It is suggested that this less localized change results from augmentation of the central inspiratory drive which inhibits the vagal outflow to the heart. ImagesFig. 1Fig. 3Fig. 4 PMID:572871

  19. Spines as a mechanical defence: the effects of fertiliser treatment on juvenile Acacia tortilis plants

    NASA Astrophysics Data System (ADS)

    Gowda, Juan H.; Albrectsen, Benedicte R.; Ball, John P.; Sjöberg, Mikael; Palo, R. Thomas

    2003-04-01

    Using growth of different tissues in Acacia tortilis as a model, we tested current hypotheses on how nutrients affect mechanical plant defence. In a greenhouse experiment we applied a balanced commercial fertiliser (NPK) at three treatment levels to juvenile potted Acacias. As expected, plants increased in size with nutrient addition. More importantly, however, the relative mass of long spines increased significantly more than other structural components (leaves and twigs). This effect is not predicted by current nutrient availability hypotheses, which suggest either equal or proportionally lower investment in mechanical defence with increasing nutrient availability. Our results suggest that investment in spine size is nutrient limited in Acacia tortilis. It is commonly observed that the risk of damage by herbivores is highest on plants growing in nutrient-rich soils. If spines act as an effective form of anti-herbivore protection, then these plants might be expected to increase their production of physical defences (long spines) under such circumstances. Plants growing under higher nutrient conditions might therefore invest more in constitutive defences. These changes in allocation pattern are consistent with the increase in production of long spines, which are also induced by browsing.

  20. Prey survival by predator intimidation: an experimental study of peacock butterfly defence against blue tits.

    PubMed

    Vallin, Adrian; Jakobsson, Sven; Lind, Johan; Wiklund, Christer

    2005-06-22

    Long-lived butterflies that hibernate as adults are expected to have well-developed antipredation devices as a result of their long exposure to natural enemies. The peacock butterfly, Inachis io, for instance, is a cryptic leaf mimic when resting, but shifts to active defence when disturbed, performing a repeated sequence of movements exposing major eyespots on the wings accompanied by a hissing noise. We studied the effect of visual and auditory defence by staging experiments in which wild-caught blue tits, Parus caeruleus, were presented with one of six kinds of experimentally manipulated living peacock butterflies as follows: butterflies with eyespots painted over and their controls (painted on another part of the wing), butterflies with their sound production aborted (small part of wings removed) and their controls, and butterflies with eyespots painted over and sound production aborted and their controls. The results showed that eyespots alone, or in combination with sound, constituted an effective defence; only 1 out of 34 butterflies with intact eyespots was killed, whereas 13 out of 20 butterflies without eyespots were killed. The killed peacocks were eaten, indicating that they are not distasteful. Hence, intimidation by bluffing can be an efficient means of defence for an edible prey. PMID:16024383

  1. Tightening the reins: recent trend in the application of the insanity defence in Canada.

    PubMed

    Verdun-Jones, S N

    1991-01-01

    This article gives a critical overview of the Canadian courts' recent pronouncements on the so-called 'insanity defence', irresistible impulse, non-insane automatism and the disposition and rights of insanity acquittees. The inconsistencies and conflicts between a number of court decisions relating to section 16(2) of the Criminal Code are highlighted and reform proposals analysed.

  2. Civil Defence Pedagogies and Narratives of Democracy: Disaster Education in Germany

    ERIC Educational Resources Information Center

    Chadderton, Charlotte

    2015-01-01

    "Disaster education" is a fledgling area of study in lifelong education. Many countries educate their populations for disasters, to mitigate potential damage and loss of life, as well as contribute to national security. In this paper, which draws on interview data from the German Federal Office for Civil Defence and Disaster Assistance…

  3. The Learning Management System at the Defence University: Awareness and Application

    ERIC Educational Resources Information Center

    Juhary, Jowati

    2013-01-01

    This brief paper examines the issues of awareness and application of a Learning Management System (LMS) used at the National Defence University of Malaysia (NDUM), Kuala Lumpur Malaysia. The paper argues that due to the discouraging responses from academics at the university on using the LMS, proactive measures must be taken immediately in order…

  4. Cooperative nest defence in red-winged blackbirds: reciprocal altruism, kinship or by-product mutualism?

    PubMed

    Olendorf, Robert; Getty, Thomas; Scribner, Kim

    2004-01-22

    Male red-winged blackbirds (Agelaius phoeniceus) often cooperate with their neighbours in defending nests against predators. Some studies have suggested that this is an example of by-product mutualism, whereas others have suggested the possibility of reciprocal altruism. No study has addressed the possibility of kin-selected cooperation in nest defence in this species. Reciprocal altruism, kin selection and by-product mutualism are not mutually exclusive alternatives, but few studies of territorial neighbours have tested for multiple mechanisms simultaneously. We test for these three possibilities in a population of red-winged blackbirds. We used simulated defections to test for reciprocal altruism. We used analysis of microsatellite loci to test for kin selection between adult male neighbours. We also used microsatellite loci to test for by-product mutualism resulting from nest defence of offspring sired on neighbouring territories. We found that male red-winged blackbirds cooperate in nest defence primarily as a form of reciprocal altruism. Experimental males reduced their level of nest defence relative to controls following simulated defection by a neighbour. In contrast to some earlier studies, we found no evidence for by-product mutualism: males did not defend nests where they had sired extra-pair offspring. We also found no evidence for kin selection: males were no more cooperative with more closely related neighbours. Considered alongside the results from other studies, our study suggests that mechanisms stabilizing cooperation in red-winged blackbirds may vary among populations.

  5. Predator responses to novel haemolymph defences of Western corn rootworm (Diabrotica virgifera) larvae

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Many herbivorous arthropods use defensive chemistry to discourage predators from attacking. This chemistry relies on the ability of predators to rapidly learn to recognize and avoid offensive stimuli. Western corn rootworm (WCR) employs multifaceted chemical defences in its haemolymph, which may c...

  6. [Defects in antioxidant defence enhance glyoxal toxicity in the yeast Saccharomyces cerevisiae].

    PubMed

    Semchyshyn, H M

    2013-01-01

    Glyoxal being either exogenous or endogenous compound belongs to reactive carbonyl species. In particular, its level increases under disturbance of the balance of glucose intracellular metabolism as well as of other reductive carbohydrates. Having two carbonyl reactive groups, glyoxal readily enters glycation reaction that results in carbonyl stress development. Investigations of different model systems demonstrate a strong relationship between carbonyl and oxidative stress. However, a possible role of antioxidant system in the organisms' defence against carbonyl stress is poor understood. In addition, the influence of glyoxal on living organisms is less studied than the effect of such carbonyl reactive species as malonic aldehyde or methylglyoxal. To study a potential role of antioxidant system in organisms' defence against carbonyl stress induced by glyoxal, the baker's yeast Saccharomyces cerevisiae was used. It has been found that strains with different defects in the antioxidant defence were more sensitive to glyoxal as compared with parental wild strain. Therefore, the data obtained in the present study confirm the relationship between carbonyl and oxidative stress and reveal the important role of antioxidant system in baker's yeast defence against carbonyl stress induced by glyoxal.

  7. The effect of inbreeding on defence against multiple enemies in Datura stramonium.

    PubMed

    Bello-Bedoy, R; Núñez-Farfán, J

    2011-03-01

    The ability of plants to respond to natural enemies might depend on the availability of genetic variation for the optimal phenotypic expression of defence. Selfing can affect the distribution of genetic variability of plant fitness, resistance and tolerance to herbivores and pathogens. The hypothesis of inbreeding depression influencing plant defence predicts that inbreeding would reduce resistance and tolerance to damage by natural enemies relative to outcrossing. In a field experiment entailing experimentally produced inbred and outcrossed progenies, we assessed the effects of one generation of selfing on Datura stramonium resistance and tolerance to three types of natural enemies, herbivores, weevils and a virus. We also examined the effect of damage on relative growth rate (RGR), flower, fruit, and seed production in inbred and outcrossed plants. Inbreeding significantly reduced plant defence to natural enemies with an increase of 4% in herbivore damage and 8% in viral infection. These results indicate inbreeding depression in total resistance. Herbivory increased 10% inbreeding depression in seed number, but viral damage caused inbred and outcrossed plants to have similar seed production. Inbreeding and outcrossing effects on fitness components were highly variable among families, implying that different types or numbers of recessive deleterious alleles segregate following inbreeding in D. stramonium. Although inbreeding did not equally alter all the interactions, our findings indicate that inbreeding reduced plant defence to herbivores and pathogens in D. stramonium.

  8. Protect and Survive: "Whiteness" and the Middle-Class Family in Civil Defence Pedagogies

    ERIC Educational Resources Information Center

    Preston, John

    2008-01-01

    "Civil defence pedagogies" normalise continuous emergency through educational channels such as school, community and adult education. Using critical whiteness studies, and critiques of white supremacy from critical race theory, as a conceptual base, the protection of whiteness, and particularly the white middle-class family, is considered to be…

  9. Prey survival by predator intimidation: an experimental study of peacock butterfly defence against blue tits.

    PubMed

    Vallin, Adrian; Jakobsson, Sven; Lind, Johan; Wiklund, Christer

    2005-06-22

    Long-lived butterflies that hibernate as adults are expected to have well-developed antipredation devices as a result of their long exposure to natural enemies. The peacock butterfly, Inachis io, for instance, is a cryptic leaf mimic when resting, but shifts to active defence when disturbed, performing a repeated sequence of movements exposing major eyespots on the wings accompanied by a hissing noise. We studied the effect of visual and auditory defence by staging experiments in which wild-caught blue tits, Parus caeruleus, were presented with one of six kinds of experimentally manipulated living peacock butterflies as follows: butterflies with eyespots painted over and their controls (painted on another part of the wing), butterflies with their sound production aborted (small part of wings removed) and their controls, and butterflies with eyespots painted over and sound production aborted and their controls. The results showed that eyespots alone, or in combination with sound, constituted an effective defence; only 1 out of 34 butterflies with intact eyespots was killed, whereas 13 out of 20 butterflies without eyespots were killed. The killed peacocks were eaten, indicating that they are not distasteful. Hence, intimidation by bluffing can be an efficient means of defence for an edible prey.

  10. Responses of foliar antioxidative and photoprotective defence systems of trees to drought: a meta-analysis.

    PubMed

    Wujeska, Agnieszka; Bossinger, Gerd; Tausz, Michael

    2013-10-01

    Current climate change predictions hint to more frequent extreme weather events, including extended droughts, making better understanding of the impacts of water stress on trees even more important. At the individual plant level, stomatal closure as a result of water deficit leads to reduced CO2 availability in the leaf, which can lead to photo-oxidative stress. Photorespiration and the Mehler reaction can maintain electron transport rates under low internal CO2, but result in production of reactive oxygen species (ROS). If electron consumption is decreased, upstream photochemical processes can be affected and light energy is absorbed in excess of photochemical requirements. Trees evolved to cope with excess energy and elevated concentration of ROS by activating photoprotective and antioxidative defence systems. The meta-analysis we present here assessed responses of these defence systems reported in 50 studies. We found responses to vary depending on stress intensity, foliage type and habitat, and on whether experiments were done in the field or in controlled environments. In general, drought increased concentrations of antioxidants and photoprotective pigments. However, severe stress caused degradation of antioxidant concentrations and oxidation of antioxidant pools. Evergreen trees seemed to preferentially reinforce membrane-bound protection systems zeaxanthin and tocopherol, whereas deciduous species showed greater responses in water-soluble antioxidants ascorbic acid and glutathione. Trees and shrubs from arid versus humid habitats vary in their antioxidative and photoprotective defence responses. In field experiments, drought had greater effects on some defence compounds than under controlled conditions.

  11. Behavioural flexibility of the chemical defence in the parasitoid wasp Leptopilina heterotoma.

    PubMed

    Stökl, Johannes; Machacek, Zora; Ruther, Joachim

    2015-12-01

    Many insects use chemical defence mechanisms to defend themselves against predators. However, defensive secretions are costly to produce and should thus only be used in cases of real danger. This would require that insects are able to discriminate between predators to adjust their chemical defence. Here, we show that females of the parasitoid wasp Leptopilina heterotoma adjust the intensity of their chemical defence to differently sized predators. If attacked by Myrmica ants, the females always released their defensive secretion, which consists mainly of (-)-iridomyrmecin. However, if attacked by smaller Cardiocondyla ants, most females did not release any defensive spray, irrespective of the duration of the ant's aggression. When in contact with non-aggressive Nasonia wasps, the females of L. heterotoma did not release any defensive secretion. Our data show that females of L. heterotoma are able to discriminate between two predators and suggest that a predator of a certain size or strength is necessary to trigger the chemical defence mechanism of L. heterotoma. PMID:26492890

  12. Adaptive molecular evolution of a defence gene in sexual but not functionally asexual evening primroses.

    PubMed

    Hersch-Green, E I; Myburg, H; Johnson, M T J

    2012-08-01

    Theory predicts that sexual reproduction provides evolutionary advantages over asexual reproduction by reducing mutational load and increasing adaptive potential. Here, we test the latter prediction in the context of plant defences against pathogens because pathogens frequently reduce plant fitness and drive the evolution of plant defences. Specifically, we ask whether sexual evening primrose plant lineages (Onagraceae) have faster rates of adaptive molecular evolution and altered gene expression of a class I chitinase, a gene implicated in defence against pathogens, than functionally asexual evening primrose lineages. We found that the ratio of amino acid to silent substitutions (K(a) /K(s) = 0.19 vs. 0.11 for sexual and asexual lineages, respectively), the number of sites identified to be under positive selection (four vs. zero for sexual and asexual lineages, respectively) and the expression of chitinase were all higher in sexual than in asexual lineages. Our results are congruent with the conclusion that a loss of sexual recombination and segregation in the Onagraceae negatively affects adaptive structural and potentially regulatory evolution of a plant defence protein.

  13. Dopamine is a key regulator in the signalling pathway underlying predator-induced defences in Daphnia.

    PubMed

    Weiss, Linda C; Leese, Florian; Laforsch, Christian; Tollrian, Ralph

    2015-10-01

    The waterflea Daphnia is a model to investigate the genetic basis of phenotypic plasticity resulting from one differentially expressed genome. Daphnia develops adaptive phenotypes (e.g. morphological defences) thwarting predators, based on chemical predator cue perception. To understand the genomic basis of phenotypic plasticity, the description of the precedent cellular and neuronal mechanisms is fundamental. However, key regulators remain unknown. All neuronal and endocrine stimulants were able to modulate but not induce defences, indicating a pathway of interlinked steps. A candidate able to link neuronal with endocrine responses is the multi-functional amine dopamine. We here tested its involvement in trait formation in Daphnia pulex and Daphnia longicephala using an induction assay composed of predator cues combined with dopaminergic and cholinergic stimulants. The mere application of both stimulants was sufficient to induce morphological defences. We determined dopamine localization in cells found in close association with the defensive trait. These cells serve as centres controlling divergent morphologies. As a mitogen and sclerotization agent, we anticipate that dopamine is involved in proliferation and structural formation of morphological defences. Furthermore, dopamine pathways appear to be interconnected with endocrine pathways, and control juvenile hormone and ecdysone levels. In conclusion, dopamine is suggested as a key regulator of phenotypic plasticity.

  14. Comparing Presidents and Their Actions "To Provide for the Common Defence"

    ERIC Educational Resources Information Center

    O'Brien, Joe; Hood, Jack

    2009-01-01

    As noted by Onosko, the nature of the social studies curriculum typically results in superficial and disconnected coverage of the content with few opportunities for in-depth investigation and discussion of that content. Engaging students in a comparative study of U.S. Presidents and actions they took "to provide for the common defence" offers one…

  15. The Effectiveness, Costs and Coastal Protection Benefits of Natural and Nature-Based Defences.

    PubMed

    Narayan, Siddharth; Beck, Michael W; Reguero, Borja G; Losada, Iñigo J; van Wesenbeeck, Bregje; Pontee, Nigel; Sanchirico, James N; Ingram, Jane Carter; Lange, Glenn-Marie; Burks-Copes, Kelly A

    2016-01-01

    There is great interest in the restoration and conservation of coastal habitats for protection from flooding and erosion. This is evidenced by the growing number of analyses and reviews of the effectiveness of habitats as natural defences and increasing funding world-wide for nature-based defences-i.e. restoration projects aimed at coastal protection; yet, there is no synthetic information on what kinds of projects are effective and cost effective for this purpose. This paper addresses two issues critical for designing restoration projects for coastal protection: (i) a synthesis of the costs and benefits of projects designed for coastal protection (nature-based defences) and (ii) analyses of the effectiveness of coastal habitats (natural defences) in reducing wave heights and the biophysical parameters that influence this effectiveness. We (i) analyse data from sixty-nine field measurements in coastal habitats globally and examine measures of effectiveness of mangroves, salt-marshes, coral reefs and seagrass/kelp beds for wave height reduction; (ii) synthesise the costs and coastal protection benefits of fifty-two nature-based defence projects and; (iii) estimate the benefits of each restoration project by combining information on restoration costs with data from nearby field measurements. The analyses of field measurements show that coastal habitats have significant potential for reducing wave heights that varies by habitat and site. In general, coral reefs and salt-marshes have the highest overall potential. Habitat effectiveness is influenced by: a) the ratios of wave height-to-water depth and habitat width-to-wavelength in coral reefs; and b) the ratio of vegetation height-to-water depth in salt-marshes. The comparison of costs of nature-based defence projects and engineering structures show that salt-marshes and mangroves can be two to five times cheaper than a submerged breakwater for wave heights up to half a metre and, within their limits, become more cost

  16. The Effectiveness, Costs and Coastal Protection Benefits of Natural and Nature-Based Defences.

    PubMed

    Narayan, Siddharth; Beck, Michael W; Reguero, Borja G; Losada, Iñigo J; van Wesenbeeck, Bregje; Pontee, Nigel; Sanchirico, James N; Ingram, Jane Carter; Lange, Glenn-Marie; Burks-Copes, Kelly A

    2016-01-01

    There is great interest in the restoration and conservation of coastal habitats for protection from flooding and erosion. This is evidenced by the growing number of analyses and reviews of the effectiveness of habitats as natural defences and increasing funding world-wide for nature-based defences-i.e. restoration projects aimed at coastal protection; yet, there is no synthetic information on what kinds of projects are effective and cost effective for this purpose. This paper addresses two issues critical for designing restoration projects for coastal protection: (i) a synthesis of the costs and benefits of projects designed for coastal protection (nature-based defences) and (ii) analyses of the effectiveness of coastal habitats (natural defences) in reducing wave heights and the biophysical parameters that influence this effectiveness. We (i) analyse data from sixty-nine field measurements in coastal habitats globally and examine measures of effectiveness of mangroves, salt-marshes, coral reefs and seagrass/kelp beds for wave height reduction; (ii) synthesise the costs and coastal protection benefits of fifty-two nature-based defence projects and; (iii) estimate the benefits of each restoration project by combining information on restoration costs with data from nearby field measurements. The analyses of field measurements show that coastal habitats have significant potential for reducing wave heights that varies by habitat and site. In general, coral reefs and salt-marshes have the highest overall potential. Habitat effectiveness is influenced by: a) the ratios of wave height-to-water depth and habitat width-to-wavelength in coral reefs; and b) the ratio of vegetation height-to-water depth in salt-marshes. The comparison of costs of nature-based defence projects and engineering structures show that salt-marshes and mangroves can be two to five times cheaper than a submerged breakwater for wave heights up to half a metre and, within their limits, become more cost

  17. Actin as Deathly Switch? How Auxin Can Suppress Cell-Death Related Defence

    PubMed Central

    Chang, Xiaoli; Riemann, Michael; Liu, Qiong; Nick, Peter

    2015-01-01

    Plant innate immunity is composed of two layers – a basal immunity, and a specific effector-triggered immunity, which is often accompanied by hypersensitive cell death. Initiation of cell death depends on a complex network of signalling pathways. The phytohormone auxin as central regulator of plant growth and development represents an important component for the modulation of plant defence. In our previous work, we showed that cell death is heralded by detachment of actin from the membrane. Both, actin response and cell death, are triggered by the bacterial elicitor harpin in grapevine cells. In this study we investigated, whether harpin-triggered actin bundling is necessary for harpin-triggered cell death. Since actin organisation is dependent upon auxin, we used different auxins to suppress actin bundling. Extracellular alkalinisation and transcription of defence genes as the basal immunity were examined as well as cell death. Furthermore, organisation of actin was observed in response to pharmacological manipulation of reactive oxygen species and phospholipase D. We find that induction of defence genes is independent of auxin. However, auxin can suppress harpin-induced cell death and also counteract actin bundling. We integrate our findings into a model, where harpin interferes with an auxin dependent pathway that sustains dynamic cortical actin through the activity of phospholipase D. The antagonism between growth and defence is explained by mutual competition for signal molecules such as superoxide and phosphatidic acid. Perturbations of the auxin-actin pathway might be used to detect disturbed integrity of the plasma membrane and channel defence signalling towards programmed cell death. PMID:25933033

  18. Deimatic Display in the European Swallowtail Butterfly as a Secondary Defence against Attacks from Great Tits

    PubMed Central

    Olofsson, Martin; Eriksson, Stephan; Jakobsson, Sven; Wiklund, Christer

    2012-01-01

    Background Many animals reduce the risk of being attacked by a predator through crypsis, masquerade or, alternatively, by advertising unprofitability by means of aposematic signalling. Behavioural attributes in prey employed after discovery, however, signify the importance of also having an effective secondary defence if a predator uncovers, or is immune to, the prey’s primary defence. In butterflies, as in most animals, secondary defence generally consists of escape flights. However, some butterfly species have evolved other means of secondary defence such as deimatic displays/startle displays. The European swallowtail, Papilio machaon, employs what appears to be a startle display by exposing its brightly coloured dorsal wing surface upon disturbance and, if the disturbance continues, by intermittently protracting and relaxing its wing muscles generating a jerky motion of the wings. This display appears directed towards predators but whether it is effective in intimidating predators so that they refrain from attacks has never been tested experimentally. Methodology/Principal Findings In this study we staged encounters between a passerine predator, the great tit, Parus major, and live and dead swallowtail butterflies in a two-choice experiment. Results showed that the dead butterfly was virtually always attacked before the live butterfly, and that it took four times longer before a bird attacked the live butterfly. When the live butterfly was approached by a bird this generally elicited the butterfly’s startle display, which usually caused the approaching bird to flee. We also performed a palatability test of the butterflies and results show that the great tits seemed to find them palatable. Conclusions/Significance We conclude that the swallowtail’s startle display of conspicuous coloration and jerky movements is an efficient secondary defence against small passerines. We also discuss under what conditions predator-prey systems are likely to aid the

  19. Influence of Trichobilharzia regenti (Digenea: Schistosomatidae) on the Defence Activity of Radix lagotis (Lymnaeidae) Haemocytes

    PubMed Central

    Skála, Vladimír; Černíková, Alena; Jindrová, Zuzana; Kašný, Martin; Vostrý, Martin; Walker, Anthony J.; Horák, Petr

    2014-01-01

    Radix lagotis is an intermediate snail host of the nasal bird schistosome Trichobilharzia regenti. Changes in defence responses in infected snails that might be related to host-parasite compatibility are not known. This study therefore aimed to characterize R. lagotis haemocyte defence mechanisms and determine the extent to which they are modulated by T. regenti. Histological observations of R. lagotis infected with T. regenti revealed that early phases of infection were accompanied by haemocyte accumulation around the developing larvae 2–36 h post exposure (p.e.) to the parasite. At later time points, 44–92 h p.e., no haemocytes were observed around T. regenti. Additionally, microtubular aggregates likely corresponding to phagocytosed ciliary plates of T. regenti miracidia were observed within haemocytes by use of transmission electron microscopy. When the infection was in the patent phase, haemocyte phagocytic activity and hydrogen peroxide production were significantly reduced in infected R. lagotis when compared to uninfected counterparts, whereas haemocyte abundance increased in infected snails. At a molecular level, protein kinase C (PKC) and extracellular-signal regulated kinase (ERK) were found to play an important role in regulating these defence reactions in R. lagotis. Moreover, haemocytes from snails with patent infection displayed lower PKC and ERK activity in cell adhesion assays when compared to those from uninfected snails, which may therefore be related to the reduced defence activities of these cells. These data provide the first integrated insight into the immunobiology of R. lagotis and demonstrate modulation of haemocyte-mediated responses in patent T. regenti infected snails. Given that immunomodulation occurs during patency, interference of snail-host defence by T. regenti might be important for the sustained production and/or release of infective cercariae. PMID:25372492

  20. Warmer temperatures reduce the costs of inducible defences in the marine toad, Rhinella marinus.

    PubMed

    van Uitregt, Vincent O; Alton, Lesley A; Heiniger, Jaime; Wilson, R S

    2016-01-01

    Many of the far-reaching impacts of climate change on ecosystem function will be due to alterations in species interactions. However, our understanding of the effects of temperature on the dynamics of interactions between species is largely inadequate. Inducible defences persist in prey populations because defensive traits increase survival in the presence of predators but are costly when they are absent. Large-scale changes in the thermal climate are likely to alter the costs or benefits of these defences for ectotherms, whose physiological processes are driven by environmental temperature. A shift in costs of defensive traits would affect not only predator-prey interactions, but also the strength of selection for inducible defences in natural populations. We investigate the effect of temperature on the costs of behavioural defences in larvae of the marine toad, Rhinella marinus. Larvae were reared in the presence or absence of predator cues at both 25 and 30 °C. When exposed to predation cues, larvae reduced activity and spent less time feeding. Exposure to predation cues also reduced metabolic rate, presumably as a by-product of reducing activity levels. Larvae exposed to predation cues also grew more slowly, were smaller at metamorphosis and were poorer jumpers after metamorphosis--three traits associated with fitness in post-metamorphic anurans. We found that the costs of behavioural defences, in terms of larval growth, post-metamorphic size and jumping performance, were exacerbated at cooler temperatures. The thermal sensitivity of costs associated with defensive traits may explain geographic variation in plasticity of defensive traits in other species and suggests that changes in environmental temperature associated with climate change may affect predator-prey interactions in subtle ways not previously considered.

  1. Thermoregulation of individual paper wasps ( Polistes dominula) plays an important role in nest defence and dominance battles

    NASA Astrophysics Data System (ADS)

    Höcherl, Nicole; Tautz, Jürgen

    2015-06-01

    Paper wasps, like Polistes dominula, are considered as primitively eusocial. Hence, they are often used as model species for studies about the evolution of eusociality and dominance hierarchies. However, our knowledge about basic physiological processes in these wasps remains limited. In particular, the thermoregulation of individual wasps in their natural habitat has not yet been investigated in detail. We conducted a comprehensive field study to test their ability to respond to external hazards with elevated thorax temperatures. We presented artificial threats by applying smoke or carbon dioxide simulating fire and predator attacks, respectively, and monitored the thorax temperature of wasps on the nest using infrared thermography. We found that P. dominula workers recognized smoke and CO2 and reacted almost instantaneously and simultaneously with an increase of their thorax temperature. The maximal thorax temperature was reached about 65 s after the application of both stressors, but subsequently, the wasps showed a different behaviour pattern. No rise of the thorax temperature was detectable after an air blast was applied or in wasps resting on the nest. These observations provide evidence that P. dominula is able to heat up its thorax and that thermoregulation is employed in escape and defence reactions. Additionally, we investigated the thorax temperatures of queens during dominance battles. We found that the thorax temperature of the dominant queens rose up to 5 °C compared to that of subordinate queens that attacked the former, suggesting that the dominant queen defends herself as well as her nest.

  2. Thermoregulation of individual paper wasps (Polistes dominula) plays an important role in nest defence and dominance battles.

    PubMed

    Höcherl, Nicole; Tautz, Jürgen

    2015-06-01

    Paper wasps, like Polistes dominula, are considered as primitively eusocial. Hence, they are often used as model species for studies about the evolution of eusociality and dominance hierarchies. However, our knowledge about basic physiological processes in these wasps remains limited. In particular, the thermoregulation of individual wasps in their natural habitat has not yet been investigated in detail. We conducted a comprehensive field study to test their ability to respond to external hazards with elevated thorax temperatures. We presented artificial threats by applying smoke or carbon dioxide simulating fire and predator attacks, respectively, and monitored the thorax temperature of wasps on the nest using infrared thermography. We found that P. dominula workers recognized smoke and CO2 and reacted almost instantaneously and simultaneously with an increase of their thorax temperature. The maximal thorax temperature was reached about 65 s after the application of both stressors, but subsequently, the wasps showed a different behaviour pattern. No rise of the thorax temperature was detectable after an air blast was applied or in wasps resting on the nest. These observations provide evidence that P. dominula is able to heat up its thorax and that thermoregulation is employed in escape and defence reactions. Additionally, we investigated the thorax temperatures of queens during dominance battles. We found that the thorax temperature of the dominant queens rose up to 5 °C compared to that of subordinate queens that attacked the former, suggesting that the dominant queen defends herself as well as her nest.

  3. Frequency-dependent taste-rejection by avian predation may select for defence chemical polymorphisms in aposematic prey.

    PubMed

    Skelhorn, John; Rowe, Candy

    2005-12-22

    Chemically defended insects advertise their unpalatability to avian predators using conspicuous aposematic coloration that predators learn to avoid. Insects utilize a wide variety of different compounds in their defences, and intraspecific variation in defence chemistry is common. We propose that polymorphisms in insect defence chemicals may be beneficial to insects by increasing survival from avian predators. Birds learn to avoid a colour signal faster when individual prey possesses one of two unpalatable chemicals rather than all prey having the same defence chemical. However, for chemical polymorphisms to evolve within a species, there must be benefits that allow rare chemical morphs to increase in frequency. Using domestic chicks as predators and coloured crumbs for prey, we provide evidence that birds taste and reject proportionally more of the individuals with rare defence chemicals than those with common defence chemicals. This indicates that the way in which birds attack and reject prey could enhance the survival of rare chemical morphs and select for chemical polymorphism in aposematic species. This is the first experiment to demonstrate that predators can directly influence the form taken by prey's chemical defences.

  4. Tracing the history of plant traits under domestication in cranberries: potential consequences on anti-herbivore defences.

    PubMed

    Rodriguez-Saona, Cesar; Vorsa, Nicholi; Singh, Ajay P; Johnson-Cicalese, Jennifer; Szendrei, Zsofia; Mescher, Mark C; Frost, Christopher J

    2011-05-01

    The process of selecting certain desirable traits for plant breeding may compromise other potentially important traits, such as defences against pests; however, specific phenotypic changes occurring over the course of domestication are unknown for most domesticated plants. Cranberry (Vaccinium macrocarpon) offers a unique opportunity to study such changes: its domestication occurred recently, and we have access to the wild ancestors and intermediate varieties used in past crosses. In order to investigate whether breeding for increased yield and fruit quality traits may indirectly affect anti-herbivore defences, the chemical defences have been examined of five related cranberry varieties that span the history of domestication against a common folivore, the gypsy moth (Lymantria dispar). Direct defences were assessed by measuring the performance of gypsy moth caterpillars and levels of phenolic compounds in leaves, and indirect defences by assaying induced leaf volatile emissions. Our results suggest that breeding in cranberry has compromised plant defences: caterpillars performed best on the derived NJS98-23 (the highest-yielding variety) and its parent Ben Lear. Moreover, NJS98-23 showed reduced induction of volatile sesquiterpenes, and had lower concentrations of the defence-related hormone cis-jasmonic acid (JA) than ancestral varieties. However, induced direct defences were not obviously affected by breeding, as exogenous JA applications reduced caterpillar growth and increased the amounts of phenolics independent of variety. Our results suggest that compromised chemical defences in high-yielding cranberry varieties may lead to greater herbivore damage which, in turn, may require more intensive pesticide control measures. This finding should inform the direction of future breeding programmes.

  5. The Effectiveness, Costs and Coastal Protection Benefits of Natural and Nature-Based Defences

    PubMed Central

    Narayan, Siddharth; Beck, Michael W.; Reguero, Borja G.; Losada, Iñigo J.; van Wesenbeeck, Bregje; Pontee, Nigel; Sanchirico, James N.; Ingram, Jane Carter; Lange, Glenn-Marie; Burks-Copes, Kelly A.

    2016-01-01

    There is great interest in the restoration and conservation of coastal habitats for protection from flooding and erosion. This is evidenced by the growing number of analyses and reviews of the effectiveness of habitats as natural defences and increasing funding world-wide for nature-based defences–i.e. restoration projects aimed at coastal protection; yet, there is no synthetic information on what kinds of projects are effective and cost effective for this purpose. This paper addresses two issues critical for designing restoration projects for coastal protection: (i) a synthesis of the costs and benefits of projects designed for coastal protection (nature-based defences) and (ii) analyses of the effectiveness of coastal habitats (natural defences) in reducing wave heights and the biophysical parameters that influence this effectiveness. We (i) analyse data from sixty-nine field measurements in coastal habitats globally and examine measures of effectiveness of mangroves, salt-marshes, coral reefs and seagrass/kelp beds for wave height reduction; (ii) synthesise the costs and coastal protection benefits of fifty-two nature-based defence projects and; (iii) estimate the benefits of each restoration project by combining information on restoration costs with data from nearby field measurements. The analyses of field measurements show that coastal habitats have significant potential for reducing wave heights that varies by habitat and site. In general, coral reefs and salt-marshes have the highest overall potential. Habitat effectiveness is influenced by: a) the ratios of wave height-to-water depth and habitat width-to-wavelength in coral reefs; and b) the ratio of vegetation height-to-water depth in salt-marshes. The comparison of costs of nature-based defence projects and engineering structures show that salt-marshes and mangroves can be two to five times cheaper than a submerged breakwater for wave heights up to half a metre and, within their limits, become more

  6. Air Abrasion

    MedlinePlus

    ... delivered directly to your desktop! more... What Is Air Abrasion? Article Chapters What Is Air Abrasion? What Happens? The Pros and Cons Will I Feel Anything? Is Air Abrasion for Everyone? print full article print this ...

  7. Major bacterial lineages are essentially devoid of CRISPR-Cas viral defence systems

    PubMed Central

    Burstein, David; Sun, Christine L.; Brown, Christopher T.; Sharon, Itai; Anantharaman, Karthik; Probst, Alexander J.; Thomas, Brian C.; Banfield, Jillian F.

    2016-01-01

    Current understanding of microorganism–virus interactions, which shape the evolution and functioning of Earth's ecosystems, is based primarily on cultivated organisms. Here we investigate thousands of viral and microbial genomes recovered using a cultivation-independent approach to study the frequency, variety and taxonomic distribution of viral defence mechanisms. CRISPR-Cas systems that confer microorganisms with immunity to viruses are present in only 10% of 1,724 sampled microorganisms, compared with previous reports of 40% occurrence in bacteria and 81% in archaea. We attribute this large difference to the lack of CRISPR-Cas systems across major bacterial lineages that have no cultivated representatives. We correlate absence of CRISPR-Cas with lack of nucleotide biosynthesis capacity and a symbiotic lifestyle. Restriction systems are well represented in these lineages and might provide both non-specific viral defence and access to nucleotides. PMID:26837824

  8. A Simplified Approach To Include Essential Facilities In Risk Scenarios For Civil Defence Plans.

    NASA Astrophysics Data System (ADS)

    González, M.; Susagna, T.; Goula, X.; Roca, A.; Safina, S.

    Given the importance of essential facilities in an earthquake crisis, it is recommended that detailed studies for assessing their functional vulnerability should be carried out. Although there have been many experiences in past earthquakes showing the problems associated to the damages to these facilities, like hospitals and police and firemen departments, many civil defence plans do not take into account their vulnerability. In some cases the reason is that there has not been opportunity to perform detailed vulnerability studies for these buildings before the issue of the prevention plans. A simplified statistical approach for the quick evaluation of the functional vulnerability of firemen stations and hospitals has been developed. This method allows these building to be at least considered in a first approach within the emergency plans. The method has been applied to facilities in Catalonia, Spain and have been incorporated to the recent developed plans of the Civil Defence department.

  9. Health protection during the Ebola crisis: the Defence Medical Services approach.

    PubMed

    Bricknell, Martin; Terrell, A; Ross, D; White, D

    2016-06-01

    This paper is a narrative of the policies, procedures, mitigations and observations of the application of Force Health Protection measures applied by the Ministry of Defence (MOD) for the deployment of military personnel to West Africa as part of the UK contribution to the international response to the Ebola crisis from July 2014 to July 2015. The MOD divided the threat into three risk categories: risk from disease and non-battle injury, Ebola risk for non-clinical duties and Ebola risk for healthcare workers. Overall risk management was directed and monitored by the OP GRITROCK Force Health Protection Board. There were six cases of malaria, four outbreaks of gastrointestinal disease, two needlestick injuries in Ebola-facing healthcare workers, one MOD Ebola case and five non-needlestick, high-risk exposures. This experience reinforces the requirement for the Defence Medical Services to have a high level of organisational competence to advise on Force Health Protection for the MOD.

  10. Invertebrate extracellular phagocyte traps show that chromatin is an ancient defence weapon

    PubMed Central

    Robb, Calum T.; Dyrynda, Elisabeth A.; Gray, Robert D.; Rossi, Adriano G.; Smith, Valerie J.

    2014-01-01

    Controlled release of chromatin from the nuclei of inflammatory cells is a process that entraps and kills microorganisms in the extracellular environment. Now termed ETosis, it is important for innate immunity in vertebrates. Paradoxically, however, in mammals, it can also contribute to certain pathologies. Here we show that ETosis occurs in several invertebrate species, including, remarkably, an acoelomate. Our findings reveal that the phenomenon is primordial and predates the evolution of the coelom. In invertebrates, the released chromatin participates in defence not only by ensnaring microorganisms and externalizing antibacterial histones together with other haemocyte-derived defence factors, but crucially, also provides the scaffold on which intact haemocytes assemble during encapsulation; a response that sequesters and kills potential pathogens infecting the body cavity. This insight into the early origin of ETosis identifies it as a very ancient process that helps explain some of its detrimental effects in mammals. PMID:25115909

  11. Ocean acidification disrupts induced defences in the intertidal gastropod Littorina littorea.

    PubMed

    Bibby, Ruth; Cleall-Harding, Polly; Rundle, Simon; Widdicombe, Steve; Spicer, John

    2007-12-22

    Carbon dioxide-induced ocean acidification is predicted to have major implications for marine life, but the research focus to date has been on direct effects. We demonstrate that acidified seawater can have indirect biological effects by disrupting the capability of organisms to express induced defences, hence, increasing their vulnerability to predation. The intertidal gastropod Littorina littorea produced thicker shells in the presence of predation (crab) cues but this response was disrupted at low seawater pH. This response was accompanied by a marked depression in metabolic rate (hypometabolism) under the joint stress of high predation risk and reduced pH. However, snails in this treatment apparently compensated for a lack of morphological defence, by increasing their avoidance behaviour, which, in turn, could affect their interactions with other organisms. Together, these findings suggest that biological effects from ocean acidification may be complex and extend beyond simple direct effects. PMID:17939976

  12. Major bacterial lineages are essentially devoid of CRISPR-Cas viral defence systems

    DOE PAGES

    Burstein, David; Sun, Christine L.; Brown, Christopher T.; Sharon, Itai; Anantharaman, Karthik; Probst, Alexander J.; Thomas, Brian C.; Banfield, Jillian F.

    2016-02-03

    Here, current understanding of microorganism–virus interactions, which shape the evolution and functioning of Earth’s ecosystems, is based primarily on cultivated organisms. Here we investigate thousands of viral and microbial genomes recovered using a cultivation independent approach to study the frequency, variety and taxonomic distribution of viral defence mechanisms. CRISPR-Cas systems that confer microorganisms with immunity to viruses are present in only 10% of 1,724 sampled microorganisms, compared with previous reports of 40% occurrence in bacteria and 81% in archaea. We attribute this large difference to the lack of CRISPR-Cas systems across major bacterial lineages that have no cultivated representatives. Wemore » correlate absence of CRISPR-Cas with lack of nucleotide biosynthesis capacity and a symbiotic lifestyle. Restriction systems are well represented in these lineages and might provide both non-specific viral defence and access to nucleotides.« less

  13. The oxidant defence system in water-buffaloes (Bubalus bubalis) experimentally infected with Anaplasma marginale.

    PubMed

    Reddy, G R; More, T; Sharma, S P; Singh, L N

    1988-03-01

    The glutathione (GSH) -oxidant defence system protects the erythrocytes and leucocytes from oxidative damage. Leucocyte -superoxide dismutase (SOD), GSH-peroxidase (GSH-px), GSH-reductase (GR), GSH-S-transferase (GSH-S-t) and arginase were examined in samples from buffaloes infected with Anaplasma marginale. All the enzymes, except arginase, were also studied in the red cell haemolysates from these animals. GSH-S-t, GSH- and glutathione-reductase (GR) levels in leucocytes decreased in infected animals suggesting a decline in the efficiency of the GSH-oxidant defence system. SOD levels increased but there was no change in leucocyte-arginase activity due to infection. Infection caused no significant changes in red cell SOD, GSH-px, GR and GSH. However, GSH-S-t significantly decreased (P less than 0.05).

  14. Health protection during the Ebola crisis: the Defence Medical Services approach.

    PubMed

    Bricknell, Martin; Terrell, A; Ross, D; White, D

    2016-06-01

    This paper is a narrative of the policies, procedures, mitigations and observations of the application of Force Health Protection measures applied by the Ministry of Defence (MOD) for the deployment of military personnel to West Africa as part of the UK contribution to the international response to the Ebola crisis from July 2014 to July 2015. The MOD divided the threat into three risk categories: risk from disease and non-battle injury, Ebola risk for non-clinical duties and Ebola risk for healthcare workers. Overall risk management was directed and monitored by the OP GRITROCK Force Health Protection Board. There were six cases of malaria, four outbreaks of gastrointestinal disease, two needlestick injuries in Ebola-facing healthcare workers, one MOD Ebola case and five non-needlestick, high-risk exposures. This experience reinforces the requirement for the Defence Medical Services to have a high level of organisational competence to advise on Force Health Protection for the MOD. PMID:26744191

  15. Getting soldiers with brain injury back to work: the defence medical rehabilitation centre neurological vocational pathway.

    PubMed

    Olivier, Elizabeth; Duncan-Anderson, J; Mitchell, J; Etherington, J; McGilloway, E

    2016-04-01

    The Neuro-Rehabilitation Group at the Defence Medical Rehabilitation Centre (DMRC) has developed an integrated vocational pathway to transition service personnel back into employment. This article describes how vocational rehabilitation at DMRC fits with the wider UK military, in comparison with civilian rehabilitation. It also describes the ongoing development of the vocational pathway, which contributes to improved outcomes from neurological disorders, including traumatic brain injury. We present two cases to highlight how the programme integrates with and influences patient care. PMID:26661477

  16. Defence force activities in marine protected areas: environmental management of Shoalwater Bay Training Area, Queensland, Australia

    NASA Astrophysics Data System (ADS)

    Wu, Wen; Wang, Xiaohua; Paull, David; Kesby, Julie

    2010-05-01

    Environmental management of military activities is of growing global concern by defence forces. As one of the largest landholders in Australia, the Australian Defence Force (ADF) is increasingly concerned with sustainable environmental management. This paper focuses on how the ADF is maintaining effective environmental management, especially in environmentally sensitive marine protected areas. It uses Shoalwater Bay Training Area (SWBTA) as a research example to examine environmental management strategies conducted by the ADF. SWBTA is one of the most significant Defence training areas in Australia, with a large number of single, joint and combined military exercises conducted in the area. With its maritime component contained in the Great Barrier Reef Marine Park (GBRMP), the Great Barrier Reef World Heritage Area (GBRWHA), and abutting Queensland’s State Marine Parks, it has high protection values. It is therefore vital for the ADF to adopt environmentally responsible management while they are conducting military activities. As to various tools employed to manage environmental performance, the ISO 14001 Environmental Management System (EMS) is widely used by the ADF. This paper examines military activities and marine environmental management within SWBTA, using the Talisman Saber (TS) exercise series as an example. These are extensive joint exercises conducted by the ADF and the United States defence forces. The paper outlines relevant legislative framework and environmental policies, analyses how the EMS operates in environmental management of military activities, and how military activities comply with these regulations. It discusses the implementation of the ADF EMS, including risk reduction measures, environmental awareness training, consultation and communication with stakeholders. A number of environmental management actions used in the TS exercises are presented to demonstrate the EMS application. Our investigations to this point indicate that the ADF is

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

    PubMed

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

    2015-02-01

    Non-self-recognition of microorganisms partly relies on the perception of microbe-associated molecular patterns (MAMPs) and leads to the activation of an innate immune response. Bacillus subtilis produces three main families of cyclic lipopeptides (LPs), namely surfactins, iturins and fengycins. Although LPs are involved in induced systemic resistance (ISR) activation, little is known about defence responses induced by these molecules and their involvement in local resistance to fungi. Here, we showed that purified surfactin, mycosubtilin (iturin family) and plipastatin (fengycin family) are perceived by grapevine plant cells. Although surfactin and mycosubtilin stimulated grapevine innate immune responses, they differentially activated early signalling pathways and defence gene expression. By contrast, plipastatin perception by grapevine cells only resulted in early signalling activation. Gene expression analysis suggested that mycosubtilin activated salicylic acid (SA) and jasmonic acid (JA) signalling pathways, whereas surfactin mainly induced an SA-regulated response. Although mycosubtilin and plipastatin displayed direct antifungal activity, only surfactin and mycosubtilin treatments resulted in a local long-lasting enhanced tolerance to the necrotrophic fungus Botrytis cinerea in grapevine leaves. Moreover, challenge with specific strains overproducing surfactin and mycosubtilin led to a slightly enhanced stimulation of the defence response compared with the LP-non-producing strain of B. subtilis. Altogether, our results provide the first comprehensive view of the involvement of LPs from B. subtilis in grapevine plant defence and local resistance against the necrotrophic pathogen Bo. cinerea. Moreover, this work is the first to highlight the ability of mycosubtilin to trigger an immune response in plants. PMID:25040001

  18. Cascading effects of induced terrestrial plant defences on aquatic and terrestrial ecosystem function

    PubMed Central

    Jackrel, Sara L.; Wootton, J. Timothy

    2015-01-01

    Herbivores induce plants to undergo diverse processes that minimize costs to the plant, such as producing defences to deter herbivory or reallocating limited resources to inaccessible portions of the plant. Yet most plant tissue is consumed by decomposers, not herbivores, and these defensive processes aimed to deter herbivores may alter plant tissue even after detachment from the plant. All consumers value nutrients, but plants also require these nutrients for primary functions and defensive processes. We experimentally simulated herbivory with and without nutrient additions on red alder (Alnus rubra), which supplies the majority of leaf litter for many rivers in western North America. Simulated herbivory induced a defence response with cascading effects: terrestrial herbivores and aquatic decomposers fed less on leaves from stressed trees. This effect was context dependent: leaves from fertilized-only trees decomposed most rapidly while leaves from fertilized trees receiving the herbivory treatment decomposed least, suggesting plants funnelled a nutritionally valuable resource into enhanced defence. One component of the defence response was a decrease in leaf nitrogen leading to elevated carbon : nitrogen. Aquatic decomposers prefer leaves naturally low in C : N and this altered nutrient profile largely explains the lower rate of aquatic decomposition. Furthermore, terrestrial soil decomposers were unaffected by either treatment but did show a preference for local and nitrogen-rich leaves. Our study illustrates the ecological implications of terrestrial herbivory and these findings demonstrate that the effects of selection caused by terrestrial herbivory in one ecosystem can indirectly shape the structure of other ecosystems through ecological fluxes across boundaries. PMID:25788602

  19. DELLA proteins modulate Arabidopsis defences induced in response to caterpillar herbivory.

    PubMed

    Lan, Zhiyi; Krosse, Sebastian; Achard, Patrick; van Dam, Nicole M; Bede, Jacqueline C

    2014-02-01

    Upon insect herbivory, many plant species change the direction of metabolic flux from growth into defence. Two key pathways modulating these processes are the gibberellin (GA)/DELLA pathway and the jasmonate pathway. In this study, the effect of caterpillar herbivory on plant-induced responses was compared between wild-type Arabidopsis thaliana (L.) Heynh. and quad-della mutants that have constitutively elevated GA responses. The labial saliva (LS) of caterpillars of the beet armyworm, Spodoptera exigua, is known to influence induced plant defence responses. To determine the role of this herbivore cue in determining metabolic shifts, plants were subject to herbivory by caterpillars with intact or impaired LS secretions. In both wild-type and quad-della plants, a jasmonate burst is an early response to caterpillar herbivory. Negative growth regulator DELLA proteins are required for the LS-mediated suppression of hormone levels. Jasmonate-dependent marker genes are induced in response to herbivory independently of LS, with the exception of AtPDF1.2 that showed LS-dependent expression in the quad-della mutant. Early expression of the salicylic acid (SA)-marker gene, AtPR1, was not affected by herbivory which also reflected SA hormone levels; however, this gene showed LS-dependent expression in the quad-della mutant. DELLA proteins may positively regulate glucosinolate levels and suppress laccase-like multicopper oxidase activity in response to herbivory. The present results show a link between DELLA proteins and early, induced plant defences in response to insect herbivory; in particular, these proteins are necessary for caterpillar LS-associated attenuation of defence hormones. PMID:24399173

  20. Cascading effects of induced terrestrial plant defences on aquatic and terrestrial ecosystem function.

    PubMed

    Jackrel, Sara L; Wootton, J Timothy

    2015-04-22

    Herbivores induce plants to undergo diverse processes that minimize costs to the plant, such as producing defences to deter herbivory or reallocating limited resources to inaccessible portions of the plant. Yet most plant tissue is consumed by decomposers, not herbivores, and these defensive processes aimed to deter herbivores may alter plant tissue even after detachment from the plant. All consumers value nutrients, but plants also require these nutrients for primary functions and defensive processes. We experimentally simulated herbivory with and without nutrient additions on red alder (Alnus rubra), which supplies the majority of leaf litter for many rivers in western North America. Simulated herbivory induced a defence response with cascading effects: terrestrial herbivores and aquatic decomposers fed less on leaves from stressed trees. This effect was context dependent: leaves from fertilized-only trees decomposed most rapidly while leaves from fertilized trees receiving the herbivory treatment decomposed least, suggesting plants funnelled a nutritionally valuable resource into enhanced defence. One component of the defence response was a decrease in leaf nitrogen leading to elevated carbon : nitrogen. Aquatic decomposers prefer leaves naturally low in C : N and this altered nutrient profile largely explains the lower rate of aquatic decomposition. Furthermore, terrestrial soil decomposers were unaffected by either treatment but did show a preference for local and nitrogen-rich leaves. Our study illustrates the ecological implications of terrestrial herbivory and these findings demonstrate that the effects of selection caused by terrestrial herbivory in one ecosystem can indirectly shape the structure of other ecosystems through ecological fluxes across boundaries. PMID:25788602

  1. Epichloë Endophytes Alter Inducible Indirect Defences in Host Grasses

    PubMed Central

    Li, Tao; Blande, James D.; Gundel, Pedro E.; Helander, Marjo; Saikkonen, Kari

    2014-01-01

    Epichloë endophytes are common symbionts living asymptomatically in pooid grasses and may provide chemical defences against herbivorous insects. While the mechanisms underlying these fungal defences have been well studied, it remains unknown whether endophyte presence affects the host's own defences. We addressed this issue by examining variation in the impact of Epichloë on constitutive and herbivore-induced emissions of volatile organic compounds (VOC), a well-known indirect plant defence, between two grass species, Schedonorus phoenix (ex. Festuca arundinacea; tall fescue) and Festuca pratensis (meadow fescue). We found that feeding by a generalist aphid species, Rhopalosiphum padi, induced VOC emissions by uninfected plants of both grass species but to varying extents, while mechanical wounding failed to do so in both species after one day of damage. Interestingly, regardless of damage treatment, Epichloë uncinata-infected F. pratensis emitted significantly lower quantities of VOCs than their uninfected counterparts. In contrast, Epichloë coenophiala-infected S. phoenix did not differ from their uninfected counterparts in constitutive VOC emissions but tended to increase VOC emissions under intense aphid feeding. A multivariate analysis showed that endophyte status imposed stronger differences in VOC profiles of F. pratensis than damage treatment, while the reverse was true for S. phoenix. Additionally, both endophytes inhibited R. padi population growth as measured by aphid dry biomass, with the inhibition appearing greater in E. uncinata-infected F. pratensis. Our results suggest, not only that Epichloë endophytes may play important roles in mediating host VOC responses to herbivory, but also that the magnitude and direction of such responses may vary with the identity of the Epichloë–grass symbiosis. Whether Epichloë-mediated host VOC responses will eventually translate into effects on higher trophic levels merits future investigation. PMID:24978701

  2. Provoking misunderstanding: a comment on Black's defence of value-free sociology.

    PubMed

    Hammersley, Martyn

    2014-09-01

    This paper is a response to a recent article dealing with the concept of value-free sociology by Donald Black. It argues that while a defence of Weber's position on the role of values in sociological research is necessary and important, what is offered by Black is counter-productive in important respects. This is because it encourages some of the misunderstandings that it is aimed at remedying and, even more importantly, offers a simplistic discussion of what are complex issues.

  3. Drought-induced trans-generational tradeoff between stress tolerance and defence: consequences for range limits?

    PubMed Central

    Alsdurf, Jacob D.; Ripley, Tayler J.; Matzner, Steven L.; Siemens, David H.

    2013-01-01

    Areas just across species range boundaries are often stressful, but even with ample genetic variation within and among range-margin populations, adaptation towards stress tolerance across range boundaries often does not occur. Adaptive trans-generational plasticity should allow organisms to circumvent these problems for temporary range expansion; however, range boundaries often persist. To investigate this dilemma, we drought stressed a parent generation of Boechera stricta (A.Gray) A. Löve & D. Löve, a perennial wild relative of Arabidopsis, representing genetic variation within and among several low-elevation range margin populations. Boechera stricta is restricted to higher, moister elevations in temperate regions where generalist herbivores are often less common. Previous reports indicate a negative genetic correlation (genetic tradeoff) between chemical defence allocation and abiotic stress tolerance that may prevent the simultaneous evolution of defence and drought tolerance that would be needed for range expansion. In growth chamber experiments, the genetic tradeoff became undetectable among offspring sib-families whose parents had been drought treated, suggesting that the stress-induced trans-generational plasticity may circumvent the genetic tradeoff and thus enable range expansion. However, the trans-generational effects also included a conflict between plastic responses (environmental tradeoff); offspring whose parents were drought treated were more drought tolerant, but had lower levels of glucosinolate toxins that function in defence against generalist herbivores. We suggest that either the genetic or environmental tradeoff between defence allocation and stress tolerance has the potential to contribute to range limit development in upland mustards. PMID:24307931

  4. Cancer susceptibility and reproductive trade-offs: a model of the evolution of cancer defences

    PubMed Central

    Boddy, Amy M.; Kokko, Hanna; Breden, Felix; Wilkinson, Gerald S.; Aktipis, C. Athena

    2015-01-01

    The factors influencing cancer susceptibility and why it varies across species are major open questions in the field of cancer biology. One underexplored source of variation in cancer susceptibility may arise from trade-offs between reproductive competitiveness (e.g. sexually selected traits, earlier reproduction and higher fertility) and cancer defence. We build a model that contrasts the probabilistic onset of cancer with other, extrinsic causes of mortality and use it to predict that intense reproductive competition will lower cancer defences and increase cancer incidence. We explore the trade-off between cancer defences and intraspecific competition across different extrinsic mortality conditions and different levels of trade-off intensity, and find the largest effect of competition on cancer in species where low extrinsic mortality combines with strong trade-offs. In such species, selection to delay cancer and selection to outcompete conspecifics are both strong, and the latter conflicts with the former. We discuss evidence for the assumed trade-off between reproductive competitiveness and cancer susceptibility. Sexually selected traits such as ornaments or large body size require high levels of cell proliferation and appear to be associated with greater cancer susceptibility. Similar associations exist for female traits such as continuous egg-laying in domestic hens and earlier reproductive maturity. Trade-offs between reproduction and cancer defences may be instantiated by a variety of mechanisms, including higher levels of growth factors and hormones, less efficient cell-cycle control and less DNA repair, or simply a larger number of cell divisions (relevant when reproductive success requires large body size or rapid reproductive cycles). These mechanisms can affect intra- and interspecific variation in cancer susceptibility arising from rapid cell proliferation during reproductive maturation, intrasexual competition and reproduction. PMID:26056364

  5. Chemical Diversity and Defence Metabolism: How Plants Cope with Pathogens and Ozone Pollution

    PubMed Central

    Iriti, Marcello; Faoro, Franco

    2009-01-01

    Chemical defences represent a main trait of the plant innate immune system. Besides regulating the relationship between plants and their ecosystems, phytochemicals are involved both in resistance against pathogens and in tolerance towards abiotic stresses, such as atmospheric pollution. Plant defence metabolites arise from the main secondary metabolic routes, the phenylpropanoid, the isoprenoid and the alkaloid pathways. In plants, antibiotic compounds can be both preformed (phytoanticipins) and inducible (phytoalexins), the former including saponins, cyanogenic glycosides and glucosinolates. Chronic exposure to tropospheric ozone (O3) stimulates the carbon fluxes from the primary to the secondary metabolic pathways to a great extent, inducing a shift of the available resources in favour of the synthesis of secondary products. In some cases, the plant defence responses against pathogens and environmental pollutants may overlap, leading to the unspecific synthesis of similar molecules, such as phenylpropanoids. Exposure to ozone can also modify the pattern of biogenic volatile organic compounds (BVOC), emitted from plant in response to herbivore feeding, thus altering the tritrophic interaction among plant, phytophagy and their natural enemies. Finally, the synthesis of ethylene and polyamines can be regulated by ozone at level of S-adenosylmethionine (SAM), the biosynthetic precursor of both classes of hormones, which can, therefore, mutually inhibit their own biosynthesis with consequence on plant phenotype. PMID:20111684

  6. Chemical diversity and defence metabolism: how plants cope with pathogens and ozone pollution.

    PubMed

    Iriti, Marcello; Faoro, Franco

    2009-07-30

    Chemical defences represent a main trait of the plant innate immune system. Besides regulating the relationship between plants and their ecosystems, phytochemicals are involved both in resistance against pathogens and in tolerance towards abiotic stresses, such as atmospheric pollution. Plant defence metabolites arise from the main secondary metabolic routes, the phenylpropanoid, the isoprenoid and the alkaloid pathways. In plants, antibiotic compounds can be both preformed (phytoanticipins) and inducible (phytoalexins), the former including saponins, cyanogenic glycosides and glucosinolates. Chronic exposure to tropospheric ozone (O(3)) stimulates the carbon fluxes from the primary to the secondary metabolic pathways to a great extent, inducing a shift of the available resources in favour of the synthesis of secondary products. In some cases, the plant defence responses against pathogens and environmental pollutants may overlap, leading to the unspecific synthesis of similar molecules, such as phenylpropanoids. Exposure to ozone can also modify the pattern of biogenic volatile organic compounds (BVOC), emitted from plant in response to herbivore feeding, thus altering the tritrophic interaction among plant, phytophagy and their natural enemies. Finally, the synthesis of ethylene and polyamines can be regulated by ozone at level of S-adenosylmethionine (SAM), the biosynthetic precursor of both classes of hormones, which can, therefore, mutually inhibit their own biosynthesis with consequence on plant phenotype.

  7. The ubiquitin conjugating enzyme, TaU4 regulates wheat defence against the phytopathogen Zymoseptoria tritici

    PubMed Central

    Millyard, Linda; Lee, Jack; Zhang, Cunjin; Yates, Gary; Sadanandom, Ari

    2016-01-01

    Mycosphaerella graminicola (Zymoseptoria tritici commonly known as Septoria), the causal agent of Septoria Leaf Blotch (STB), is considered one of the major threats to European wheat production. Previous studies have shown the importance of ubiquitination in plant defence against a multitude of pathogens. However the ubiquitination machinery in wheat is under studied, particularly E2 enzymes that have the ability to control the ubiquitination and thereby the fate of many different target proteins. In this study we identify an E2 enzyme, Triticum aestivum Ubiquitin conjugating enzyme 4 (TaU4) that functions in wheat defence against Septoria. We demonstrate TaU4 to be a bona fide E2 enzyme through an E2 charging assay. TaU4 localises in both the cytoplasm and nucleus, therefore potentially interacting with E3 ligases and substrate proteins in multiple compartments. Virus Induced Gene Silencing of TaU4 in wheat leaves resulted in delayed development of disease symptoms, reduced Septoria growth and reproduction. We conclude that TaU4 is a novel negative regulator of defence against Septoria. PMID:27759089

  8. Enterococcus faecalis zinc-responsive proteins mediate bacterial defence against zinc overload, lysozyme and oxidative stress.

    PubMed

    Abrantes, Marta C; Kok, Jan; Silva Lopes, Maria de Fátima

    2014-12-01

    Two Enterococcus faecalis genes encoding the P-type ATPase EF1400 and the putative SapB protein EF0759 were previously shown to be strongly upregulated in the presence of high concentrations of zinc. In the present work, we showed that a Zn(2+)-responsive DNA-binding motif (zim) is present in the promoter regions of these genes. Both proteins were further studied with respect to their involvement in zinc homeostasis and invasion of the host. EF0759 contributed to intramacrophage survival by an as-yet unknown mechanism(s). EF1400, here renamed ZntAEf, is an ATPase with specificity for zinc and plays a role in dealing with several host defences, i.e. zinc overload, oxidative stress and lysozyme; it provides E. faecalis cells with the ability to survive inside macrophages. As these three host defence mechanisms are important at several sites in the host, i.e. inside macrophages and in saliva, this work suggested that ZntAEf constitutes a crucial E. faecalis defence mechanism that is likely to contribute to the ability of this bacterium to endure life inside its host.

  9. Food supplementation mitigates dispersal-dependent differences in nest defence in a passerine bird.

    PubMed

    Récapet, Charlotte; Daniel, Grégory; Taroni, Joëlle; Bize, Pierre; Doligez, Blandine

    2016-05-01

    Dispersing and non-dispersing individuals often differ in phenotypic traits (e.g. physiology, behaviour), but to what extent these differences are fixed or driven by external conditions remains elusive. We experimentally tested whether differences in nest-defence behaviour between dispersing and non-dispersing individuals changed with local habitat quality in collared flycatchers, by providing additional food during the nestling rearing period. In control (non-food-supplemented) nests, dispersers were less prone to defend their brood compared with non-dispersers, whereas in food-supplemented nests, dispersing and non-dispersing individuals showed equally strong nest defence. We discuss the importance of dispersal costs versus adaptive flexibility in reproductive investment in shaping these differences in nest-defence behaviour between dispersing and non-dispersing individuals. Irrespective of the underlying mechanisms, our study emphasizes the importance of accounting for environmental effects when comparing traits between dispersing and non-dispersing individuals, and in turn assessing the costs and benefits of dispersal. PMID:27194287

  10. MIMIVIRE is a defence system in mimivirus that confers resistance to virophage.

    PubMed

    Levasseur, Anthony; Bekliz, Meriem; Chabrière, Eric; Pontarotti, Pierre; La Scola, Bernard; Raoult, Didier

    2016-03-10

    Since their discovery, giant viruses have revealed several unique features that challenge the conventional definition of a virus, such as their large and complex genomes, their infection by virophages and their presence of transferable short element transpovirons. Here we investigate the sensitivity of mimivirus to virophage infection in a collection of 59 viral strains and demonstrate lineage specificity in the resistance of mimivirus to Zamilon, a unique virophage that can infect lineages B and C of mimivirus but not lineage A. We hypothesized that mimiviruses harbour a defence mechanism resembling the clustered regularly interspaced short palindromic repeat (CRISPR)-Cas system that is widely present in bacteria and archaea. We performed de novo sequencing of 45 new mimivirus strains and searched for sequences specific to Zamilon in a total of 60 mimivirus genomes. We found that lineage A strains are resistant to Zamilon and contain the insertion of a repeated Zamilon sequence within an operon, here named the 'mimivirus virophage resistance element' (MIMIVIRE). Further analyses of the surrounding sequences showed that this locus is reminiscent of a defence mechanism related to the CRISPR-Cas system. Silencing the repeated sequence and the MIMIVIRE genes restores mimivirus susceptibility to Zamilon. The MIMIVIRE proteins possess the typical functions (nuclease and helicase) involved in the degradation of foreign nucleic acids. The viral defence system, MIMIVIRE, represents a nucleic-acid-based immunity against virophage infection. PMID:26934229

  11. Antioxidant defences in hydrated and desiccated states of the tardigrade Paramacrobiotus richtersi.

    PubMed

    Rizzo, Angela M; Negroni, Manuela; Altiero, Tiziana; Montorfano, Gigliola; Corsetto, Paola; Berselli, Patrizia; Berra, Bruno; Guidetti, Roberto; Rebecchi, Lorena

    2010-06-01

    Reactive oxygen species (ROS) are formed in all aerobic organisms, potentially leading to oxidative damage of all biological molecules. A number of defence mechanisms have developed to protect the organism from attack by ROS. Desiccation tolerance is correlated with an increase in the antioxidant potential in several organisms, but the regulation of the antioxidant defence system is complex and its role in desiccation-tolerant organisms is not yet firmly established. To determine if anhydrobiotic tardigrades have an antioxidant defence system, capable of counteracting ROS, we compared the activity of several antioxidant enzymes, the fatty acid composition and Heat shock protein expression in two physiological states (desiccated vs. hydrated) of the tardigrade Paramacrobiotus richtersi. In hydrated tardigrades, superoxide dismutase and catalase show comparable activities, while in desiccated specimens the activity of superoxide dismutase increases. Both glutathione peroxidase and glutathione were induced by desiccation. The percentage of fatty acid composition of polyunsaturated fatty acids and the amount of thiobarbituric acid reactive substances are higher in desiccated animals than in hydrated ones. Lastly, desiccated tardigrades did not differ significantly from the hydrated ones in the relative levels of Hsp70 and Hsp90. These results indicate that the possession of antioxidant metabolism could represent a crucial strategy to avoid damages during desiccation in anhydrobiotic tardigrades.

  12. Action of adenosine receptor antagonists on the cardiovascular response to defence area stimulation in the rat.

    PubMed Central

    St Lambert, J H; Dawid-Milner, M S; Silva-Carvalho, L; Spyer, K M

    1994-01-01

    1. The action of adenosine in the mediation of the cardiovascular changes associated with the defence reaction has been investigated in the rat using two A1 receptor antagonists. 2. Cumulative doses of 1,3 dipropyl-cyclopentylxanthine (DPCPX) (0.3-3 mg kg-1) and ethanol (0.03-0.25 ml) and bolus doses of DPCPX (3 mg kg-1) and 8-sulphophenyltheophylline (8-SPT) (20 mg kg-1) were given into alpha-chloralose, paralysed and artificially ventilated rats. Recordings were made of arterial blood pressure and heart rate. 3. Ethanol, the vehicle for DPCPX, failed to modify the magnitude of the defence response; however, cumulative doses of DPCPX produced a dose-dependent decrease in the HDA (hypothalamic defence area)-evoked increase in arterial blood pressure, accompanied by a similar fall in the magnitude of the evoked heart rate response. 4. The evoked rise in arterial blood pressure was reduced significantly by intravenous injection of DPCPX (3 mg kg-1) but not 8-SPT (20 mg kg-1), a purely peripherally acting adenosine antagonist. 5. These results suggest that adenosine acting at A1 receptors located in the central nervous system, is involved in the HDA-evoked pressor response. Whilst the site of action of the A1 receptors is not known, possible locations are discussed. PMID:7812606

  13. Herbivore-induced volatiles of cabbage (Brassica oleracea) prime defence responses in neighbouring intact plants.

    PubMed

    Peng, J; van Loon, J J A; Zheng, S; Dicke, M

    2011-03-01

    When attacked by herbivores, plants release herbivore-induced plant volatiles (HIPV) that may function in direct defence by repelling herbivores or reducing their growth. Emission of HIPV may also contribute to indirect defence by attracting natural enemies of the herbivore. Here, cabbage (Brassica oleracea L.) plants (receiver plants) previously exposed to HIPV and subsequently induced through feeding by five Pieris brassicae L. caterpillars attracted more Cotesia glomerata L. parasitoids than control plants. HIPVs to which receiver plants had been exposed were emitted by B. oleracea infested with 50 P. brassicae caterpillars. Control plants had been exposed to volatiles from undamaged plants. In contrast, there were no differences in the attraction of wasps to receiver plants induced through feeding of one or ten larvae of P. brassicae compared to control plants. In addition, RT-PCR demonstrated higher levels of LIPOXYGENASE (BoLOX) transcripts in HIPV-exposed receiver plants. Exposure to HIPV from emitter plants significantly inhibited the growth rate of both P. brassicae and Mamestra brassicae caterpillars compared to growth rates of caterpillars feeding on control receiver plants. Our results demonstrate plant-plant signalling leading to priming of both indirect and direct defence in HIPV-exposed B. oleracea plants.

  14. MIMIVIRE is a defence system in mimivirus that confers resistance to virophage.

    PubMed

    Levasseur, Anthony; Bekliz, Meriem; Chabrière, Eric; Pontarotti, Pierre; La Scola, Bernard; Raoult, Didier

    2016-03-10

    Since their discovery, giant viruses have revealed several unique features that challenge the conventional definition of a virus, such as their large and complex genomes, their infection by virophages and their presence of transferable short element transpovirons. Here we investigate the sensitivity of mimivirus to virophage infection in a collection of 59 viral strains and demonstrate lineage specificity in the resistance of mimivirus to Zamilon, a unique virophage that can infect lineages B and C of mimivirus but not lineage A. We hypothesized that mimiviruses harbour a defence mechanism resembling the clustered regularly interspaced short palindromic repeat (CRISPR)-Cas system that is widely present in bacteria and archaea. We performed de novo sequencing of 45 new mimivirus strains and searched for sequences specific to Zamilon in a total of 60 mimivirus genomes. We found that lineage A strains are resistant to Zamilon and contain the insertion of a repeated Zamilon sequence within an operon, here named the 'mimivirus virophage resistance element' (MIMIVIRE). Further analyses of the surrounding sequences showed that this locus is reminiscent of a defence mechanism related to the CRISPR-Cas system. Silencing the repeated sequence and the MIMIVIRE genes restores mimivirus susceptibility to Zamilon. The MIMIVIRE proteins possess the typical functions (nuclease and helicase) involved in the degradation of foreign nucleic acids. The viral defence system, MIMIVIRE, represents a nucleic-acid-based immunity against virophage infection.

  15. Neuronal development is promoted by weakened intrinsic antioxidant defences due to epigenetic repression of Nrf2

    PubMed Central

    Bell, Karen F.S.; Al-Mubarak, Bashayer; Martel, Marc-André; McKay, Sean; Wheelan, Nicola; Hasel, Philip; Márkus, Nóra M.; Baxter, Paul; Deighton, Ruth F.; Serio, Andrea; Bilican, Bilada; Chowdhry, Sudhir; Meakin, Paul J.; Ashford, Michael L.J.; Wyllie, David J.A.; Scannevin, Robert H.; Chandran, Siddharthan; Hayes, John D.; Hardingham, Giles E.

    2015-01-01

    Forebrain neurons have weak intrinsic antioxidant defences compared with astrocytes, but the molecular basis and purpose of this is poorly understood. We show that early in mouse cortical neuronal development in vitro and in vivo, expression of the master-regulator of antioxidant genes, transcription factor NF-E2-related-factor-2 (Nrf2), is repressed by epigenetic inactivation of its promoter. Consequently, in contrast to astrocytes or young neurons, maturing neurons possess negligible Nrf2-dependent antioxidant defences, and exhibit no transcriptional responses to Nrf2 activators, or to ablation of Nrf2's inhibitor Keap1. Neuronal Nrf2 inactivation seems to be required for proper development: in maturing neurons, ectopic Nrf2 expression inhibits neurite outgrowth and aborization, and electrophysiological maturation, including synaptogenesis. These defects arise because Nrf2 activity buffers neuronal redox status, inhibiting maturation processes dependent on redox-sensitive JNK and Wnt pathways. Thus, developmental epigenetic Nrf2 repression weakens neuronal antioxidant defences but is necessary to create an environment that supports neuronal development. PMID:25967870

  16. The Eileen Skellern Lecture 2014: physical restraint: in defence of the indefensible?

    PubMed

    Duxbury, J A

    2015-03-01

    Aggression is reported to be prevalent in psychiatric inpatient care and its frequency towards healthcare professionals is well documented. While aggression may not be entirely avoidable, its incidence can be reduced through prevention and the minimization of restrictive practices such as physical restraint. The study aims to explore three common 'defences' to account for the use of physical restraint; to challenge each defence with regard to the evidence base; and to identify how services are responding to the challenge of reducing the use of restrictive interventions. Following a number of investigations to highlight serious problems with the use of physical restraint, it seems timely to examine its efficacy in light of the evidence base. In order to do this, three key defences for its use will be challenged using the literature. A combination of interventions to minimize the use of restraint including advance planning tools, and recognition of potential trauma is necessary at an organizational and individual level. Patients can be severely traumatized by the use of restrictive practices and there is a drive to examine, and reduce the use and impact of using these models that incorporate trauma informed care (TIC) and person centredness. PMID:25720312

  17. How to evade a coevolving brood parasite: egg discrimination versus egg variability as host defences.

    PubMed

    Spottiswoode, Claire N; Stevens, Martin

    2011-12-01

    Arms races between avian brood parasites and their hosts often result in parasitic mimicry of host eggs, to evade rejection. Once egg mimicry has evolved, host defences could escalate in two ways: (i) hosts could improve their level of egg discrimination; and (ii) negative frequency-dependent selection could generate increased variation in egg appearance (polymorphism) among individuals. Proficiency in one defence might reduce selection on the other, while a combination of the two should enable successful rejection of parasitic eggs. We compared three highly variable host species of the Afrotropical cuckoo finch Anomalospiza imberbis, using egg rejection experiments and modelling of avian colour and pattern vision. We show that each differed in their level of polymorphism, in the visual cues they used to reject foreign eggs, and in their degree of discrimination. The most polymorphic host had the crudest discrimination, whereas the least polymorphic was most discriminating. The third species, not currently parasitized, was intermediate for both defences. A model simulating parasitic laying and host rejection behaviour based on the field experiments showed that the two host strategies result in approximately the same fitness advantage to hosts. Thus, neither strategy is superior, but rather they reflect alternative potential evolutionary trajectories.

  18. Bio-inspired approaches to sensing for defence and security applications.

    PubMed

    Biggins, Peter D E; Kusterbeck, Anne; Hiltz, John A

    2008-05-01

    Interdisciplinary research in biotechnology and related scientific areas has increased tremendously over the past decade. This rapid pace, in conjunction with advances in microfabricated systems, computer hardware, bioengineering and the availability of low-powered miniature components, has now made it feasible to design bio-inspired materials, sensors and systems with tremendous potential for defence and security applications. To realize the full potential of biotechnology and bio-inspiration, there is a need to define specific requirements to meet the challenges of the changing world and its threats. One approach to assisting the defence and security communities in defining their requirements is through the use of a conceptual model. The distributed or intelligent autonomous sensing (DIAS) system is one such model. The DIAS model is not necessarily aimed at a single component, for instance a sensor, but can include a system, or even a system of systems in the same way that a single organism, a multi-cellular organism or group of organisms is configured. This paper provides an overview of the challenges to and opportunities for bio-inspired sensors and systems together with examples of how they are being implemented. Examples focus on both learning new things from biological organisms that have application to the defence and security forces and adapting known discoveries in biology and biochemistry for practical use by these communities. PMID:18427675

  19. Evolution of separate predation- and defence-evoked venoms in carnivorous cone snails

    PubMed Central

    Dutertre, Sébastien; Jin, Ai-Hua; Vetter, Irina; Hamilton, Brett; Sunagar, Kartik; Lavergne, Vincent; Dutertre, Valentin; Fry, Bryan G.; Antunes, Agostinho; Venter, Deon J.; Alewood, Paul F.; Lewis, Richard J.

    2014-01-01

    Venomous animals are thought to inject the same combination of toxins for both predation and defence, presumably exploiting conserved target pharmacology across prey and predators. Remarkably, cone snails can rapidly switch between distinct venoms in response to predatory or defensive stimuli. Here, we show that the defence-evoked venom of Conus geographus contains high levels of paralytic toxins that potently block neuromuscular receptors, consistent with its lethal effects on humans. In contrast, C. geographus predation-evoked venom contains prey-specific toxins mostly inactive at human targets. Predation- and defence-evoked venoms originate from the distal and proximal regions of the venom duct, respectively, explaining how different stimuli can generate two distinct venoms. A specialized defensive envenomation strategy is widely evolved across worm, mollusk and fish-hunting cone snails. We propose that defensive toxins, originally evolved in ancestral worm-hunting cone snails to protect against cephalopod and fish predation, have been repurposed in predatory venoms to facilitate diversification to fish and mollusk diets. PMID:24662800

  20. Armed Rollers: Does Nestling’s Vomit Function as a Defence against Predators?

    PubMed Central

    Parejo, Deseada; Avilés, Jesús M.; Peña, Aránzazu; Sánchez, Lourdes; Ruano, Francisca; Zamora-Muñoz, Carmen; Martín-Vivaldi, Manuel

    2013-01-01

    Chemical defences against predators are widespread in the animal kingdom although have been seldom reported in birds. Here, we investigate the possibility that the orange liquid that nestlings of an insectivorous bird, the Eurasian roller (Coracias garrulus), expel when scared at their nests acts as a chemical defence against predators. We studied the diet of nestling rollers and vomit origin, its chemical composition and deterrent effect on a mammal generalist predator. We also hypothesized that nestling rollers, as their main prey (i.e. grasshoppers) do from plants, could sequester chemicals from their prey for their use. Grasshoppers, that also regurgitate when facing to a threat, store the harmful substances used by plants to defend themselves against herbivores. We found that nestling rollers only vomit after being grasped and moved. The production of vomit depended on food consumption and the vomit contained two deterrent chemicals (hydroxycinnamic and hydroxybenzoic acids) stored by grasshoppers and used by plants to diminish herbivory, suggesting that they originate from the rollers’ prey. Finally, we showed for the first time that the oral secretion of a vertebrate had a deterrent effect on a model predator because vomit of nestling rollers made meat distasteful to dogs. These results support the idea that the vomit of nestling rollers is a chemical defence against predators. PMID:23874791

  1. A chloroplast-localized protein LESION AND LAMINA BENDING affects defence and growth responses in rice.

    PubMed

    Tamiru, Muluneh; Takagi, Hiroki; Abe, Akira; Yokota, Takao; Kanzaki, Hiroyuki; Okamoto, Haruko; Saitoh, Hiromasa; Takahashi, Hideyuki; Fujisaki, Koki; Oikawa, Kaori; Uemura, Aiko; Natsume, Satoshi; Jikumaru, Yusuke; Matsuura, Hideyuki; Umemura, Kenji; Terry, Matthew J; Terauchi, Ryohei

    2016-06-01

    Understanding how plants allocate their resources to growth or defence is of long-term importance to the development of new and improved varieties of different crops. Using molecular genetics, plant physiology, hormone analysis and Next-Generation Sequencing (NGS)-based transcript profiling, we have isolated and characterized the rice (Oryza sativa) LESION AND LAMINA BENDING (LLB) gene that encodes a chloroplast-targeted putative leucine carboxyl methyltransferase. Loss of LLB function results in reduced growth and yield, hypersensitive response (HR)-like lesions, accumulation of the antimicrobial compounds momilactones and phytocassanes, and constitutive expression of pathogenesis-related genes. Consistent with these defence-associated responses, llb shows enhanced resistance to rice blast (Magnaporthe oryzae) and bacterial blight (Xanthomonas oryzae pv. oryzae). The lesion and resistance phenotypes are likely to be caused by the over-accumulation of jasmonates (JAs) in the llb mutant including the JA precursor 12-oxo-phytodienoic acid. Additionally, llb shows an increased lamina inclination and enhanced early seedling growth due to elevated brassinosteroid (BR) synthesis and/or signalling. These findings show that LLB functions in the chloroplast to either directly or indirectly repress both JA- and BR-mediated responses, revealing a possible mechanism for controlling how plants allocate resources for defence and growth. PMID:26864209

  2. An Apparent Trade-Off between Direct and Signal-Based Induced Indirect Defence against Herbivores in Willow Trees

    PubMed Central

    Yoneya, Kinuyo; Uefune, Masayoshi; Takabayashi, Junji

    2012-01-01

    Signal-based induced indirect defence refers to herbivore-induced production of plant volatiles that attract carnivorous natural enemies of herbivores. Relationships between direct and indirect defence strategies were studied using tritrophic systems consisting of six sympatric willow species, willow leaf beetles (Plagiodera versicolora), and their natural predators, ladybeetles (Aiolocaria hexaspilota). Relative preferences of ladybeetles for prey-infested willow plant volatiles, indicating levels of signal-based induced indirect defence, were positively correlated with the vulnerability of willow species to leaf beetles, assigned as relative levels of direct defence. This correlation suggested a possible trade-off among the species, in terms of resource limitation between direct defence and signal-based induced indirect defence. However, analyses of volatiles from infested and uninfested plants showed that the specificity of infested volatile blends (an important factor determining the costs of signal-based induced indirect defence) did not affect the attractiveness of infested plant volatiles. Thus, the suggested trade-off in resource limitation was unlikely. Rather, principal coordinates analysis showed that this ‘apparent trade-off’ between direct and signal-based induced indirect defence was partially explained by differential preferences of ladybeetles to infested plant volatiles of the six willow species. We also showed that relative preferences of ladybeetles for prey-infested willow plant volatiles were positively correlated with oviposition preferences of leaf beetles and with the distributions of leaf beetles in the field. These correlations suggest that ladybeetles use the specificity of infested willow plant volatiles to find suitable prey patches. PMID:23251559

  3. The synthetic cationic lipid diC14 activates a sector of the Arabidopsis defence network requiring endogenous signalling components.

    PubMed

    Cambiagno, Damián Alejandro; Lonez, Caroline; Ruysschaert, Jean-Marie; Alvarez, María Elena

    2015-12-01

    Natural and synthetic elicitors have contributed significantly to the study of plant immunity. Pathogen-derived proteins and carbohydrates that bind to immune receptors, allow the fine dissection of certain defence pathways. Lipids of a different nature that act as defence elicitors, have also been studied, but their specific effects have been less well characterized, and their receptors have not been identified. In animal cells, nanoliposomes of the synthetic cationic lipid 3-tetradecylamino-tert-butyl-N-tetradecylpropionamidine (diC14) activate the TLR4-dependent immune cascade. Here, we have investigated whether this lipid induces Arabidopsis defence responses. At the local level, diC14 activated early and late defence gene markers (FRK1, WRKY29, ICS1 and PR1), acting in a dose-dependent manner. This lipid induced the salicylic acid (SA)-dependent, but not jasmonic acid (JA)-dependent, pathway and protected plants against Pseudomonas syringae pv. tomato (Pst), but not Botrytis cinerea. diC14 was not toxic to plant or pathogen, and potentiated pathogen-induced callose deposition. At the systemic level, diC14 induced PR1 expression and conferred resistance against Pst. diC14-induced defence responses required the signalling protein EDS1, but not NDR1. Curiously, the lipid-induced defence gene expression was lower in the fls2/efr/cerk1 triple mutant, but still unchanged in the single mutants. The amidine headgroup and chain length were important for its activity. Given the robustness of the responses triggered by diC14, its specific action on a defence pathway and the requirement for well-known defence components, this synthetic lipid is emerging as a useful tool to investigate the initial events involved in plant innate immunity.

  4. Inhibitory effect of the ventral tegmental A10 region on the hypothalamic defence reaction: evidence for a possible dopaminergic mediation.

    PubMed

    Piazza, P V; Ferdico, M; Crescimanno, G; Benigno, A; Amato, G

    1987-06-16

    The influence of A10 region neurons of the ventral tegmental area (VTA) on the defence reaction evoked by stimulation of the ventromedial hypothalamic nucleus (VMH) was studied in the cat. The latency of the hissing in the defence reaction increased when the VTA was stimulated both ipsi- and contralaterally. A sulpiride (50mg/kg i.p.) injection totally abolished the VTA-provoked increase of the hissing latency without affecting the basal response. PMID:3607485

  5. Treating seeds with activators of plant defence generates long-lasting priming of resistance to pests and pathogens.

    PubMed

    Worrall, Dawn; Holroyd, Geoff H; Moore, Jason P; Glowacz, Marcin; Croft, Patricia; Taylor, Jane E; Paul, Nigel D; Roberts, Michael R

    2012-02-01

    • Priming of defence is a strategy employed by plants exposed to stress to enhance resistance against future stress episodes with minimal associated costs on growth. Here, we test the hypothesis that application of priming agents to seeds can result in plants with primed defences. • We measured resistance to arthropod herbivores and disease in tomato (Solanum lycopersicum) plants grown from seed treated with jasmonic acid (JA) and/or β-aminobutryric acid (BABA). • Plants grown from JA-treated seed showed increased resistance against herbivory by spider mites, caterpillars and aphids, and against the necrotrophic fungal pathogen, Botrytis cinerea. BABA seed treatment provided primed defence against powdery mildew disease caused by the biotrophic fungal pathogen, Oidium neolycopersici. Priming responses were long-lasting, with significant increases in resistance sustained in plants grown from treated seed for at least 8 wk, and were associated with enhanced defence gene expression during pathogen attack. There was no significant antagonism between different forms of defence in plants grown from seeds treated with a combination of JA and BABA. • Long-term defence priming by seed treatments was not accompanied by reductions in growth, and may therefore be suitable for commercial exploitation.

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

    PubMed

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

    2015-07-01

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

  7. Acoustic defence in an insect: characteristics of defensive stridulation and differences between the sexes in the tettigoniid Poecilimon ornatus (Schmidt 1850).

    PubMed

    Kowalski, Kerstin N; Lakes-Harlan, Reinhard; Lehmann, Gerlind U C; Strauß, Johannes

    2014-10-01

    Many insects exhibit secondary defence mechanisms upon contact with a predator, such as defensive sound production or regurgitation of gut contents. In the tettigoniid Poecilimon ornatus, both males and females are capable of sound production and of regurgitation. However, wing stridulatory structures for intraspecific acoustic communication evolved independently in males and females, and may result in different defence sounds. Here we investigate in P. ornatus whether secondary defence behaviours, in particular defence sounds, show sex-specific differences. The male defence sound differs significantly from the male calling song in that it has a longer syllable duration and a higher number of impulses per syllable. In females, the defence sound syllables are also significantly longer than the syllables of their response song to the male calling song. In addition, the acoustic disturbance stridulation differs notably between females and males as both sexes exhibit different temporal patterns of the defence sound. Furthermore, males use defence sounds more often than females. The higher proportion of male disturbance stridulation is consistent with a male-biased predation risk during calling and phonotactic behaviour. The temporal structures of the female and male defence sounds support a deimatic function of the startling sound in both females and males, rather than an adaptation for a particular temporal pattern. Independently of the clear differences in sound defence, no difference in regurgitation of gut content occurs between the sexes.

  8. The Internal Ballistics of an Air Gun

    ERIC Educational Resources Information Center

    Denny, Mark

    2011-01-01

    The internal ballistics of a firearm or artillery piece considers the pellet, bullet, or shell motion while it is still inside the barrel. In general, deriving the muzzle speed of a gunpowder firearm from first principles is difficult because powder combustion is fast and it very rapidly raises the temperature of gas (generated by gunpowder…

  9. Esch. coli infections in childhood. Significance of bacterial virulence and immune defence.

    PubMed Central

    Hanson, L A

    1976-01-01

    The Esch. coli harboured in the gut constitute a reservoir of potential pathogens in the infant and child. The conditions required for these intestinal inhabitants to cause infection are not well understood. The presence of virulence factors such as capsular antigens, especially K1, may be of significance for the ability of Esch. coli to cause neonatal meningitis. The capacity of certain Esch. coli to attach to epithelial cells of mucous membranes may be important for their infective powers in the urinary as well as the intestinal tract. Furthermore, the ability of certain Esch. coli to produce enterotoxins similar to that of V. cholerae is of importance for their capacity to provoke diarrhoea. The importance of the immune defence mechanisms for prevention of these Esch. coli infections is suggested, especially in the form of local immunity provided by secretory IgA antibodies. Such antibodies directed against Esch. coli O and K antigens as well as enterotoxins are present in large amounts in human milk and may be of considerable importance for protection against Esch. coli in the breast-fed baby. Breast feeding may be of special significance until the baby has built up its own local immune defence preventing the micro-organisms from attaching to and invading the intestinal mucous membranes. SIgA antibodies in urine may have a similar protective effect against urinary tract infections. The variable pictures of Esch. coli infections in childhood are striking, ranging from severe sepsis/meningitis or diarrhoea to "asymptomatic" bacteriuria. This variability is obviously closely connected with the presence of various virulence factors and the function of different components of the immune defence. PMID:795381

  10. Plant defence responses in oilseed rape MINELESS plants after attack by the cabbage moth Mamestra brassicae.

    PubMed

    Ahuja, Ishita; van Dam, Nicole Marie; Winge, Per; Trælnes, Marianne; Heydarova, Aysel; Rohloff, Jens; Langaas, Mette; Bones, Atle Magnar

    2015-02-01

    The Brassicaceae family is characterized by a unique defence mechanism known as the 'glucosinolate-myrosinase' system. When insect herbivores attack plant tissues, glucosinolates are hydrolysed by the enzyme myrosinase (EC 3.2.1.147) into a variety of degradation products, which can deter further herbivory. This process has been described as 'the mustard oil bomb'. Additionally, insect damage induces the production of glucosinolates, myrosinase, and other defences. Brassica napus seeds have been genetically modified to remove myrosinase-containing myrosin cells. These plants are termed MINELESS because they lack myrosin cells, the so-called toxic mustard oil mines. Here, we examined the interaction between B. napus wild-type and MINELESS plants and the larvae of the cabbage moth Mamestra brassicae. No-choice feeding experiments showed that M. brassicae larvae gained less weight and showed stunted growth when feeding on MINELESS plants compared to feeding on wild-type plants. M. brassicae feeding didn't affect myrosinase activity in MINELESS plants, but did reduce it in wild-type seedlings. M. brassicae feeding increased the levels of indol-3-yl-methyl, 1-methoxy-indol-3-yl-methyl, and total glucosinolates in both wild-type and MINELESS seedlings. M. brassicae feeding affected the levels of glucosinolate hydrolysis products in both wild-type and MINELESS plants. Transcriptional analysis showed that 494 and 159 genes were differentially regulated after M. brassicae feeding on wild-type and MINELESS seedlings, respectively. Taken together, the outcomes are very interesting in terms of analysing the role of myrosin cells and the glucosinolate-myrosinase defence system in response to a generalist cabbage moth, suggesting that similar studies with other generalist or specialist insect herbivores, including above- and below-ground herbivores, would be useful. PMID:25563968

  11. Plant defence responses in oilseed rape MINELESS plants after attack by the cabbage moth Mamestra brassicae.

    PubMed

    Ahuja, Ishita; van Dam, Nicole Marie; Winge, Per; Trælnes, Marianne; Heydarova, Aysel; Rohloff, Jens; Langaas, Mette; Bones, Atle Magnar

    2015-02-01

    The Brassicaceae family is characterized by a unique defence mechanism known as the 'glucosinolate-myrosinase' system. When insect herbivores attack plant tissues, glucosinolates are hydrolysed by the enzyme myrosinase (EC 3.2.1.147) into a variety of degradation products, which can deter further herbivory. This process has been described as 'the mustard oil bomb'. Additionally, insect damage induces the production of glucosinolates, myrosinase, and other defences. Brassica napus seeds have been genetically modified to remove myrosinase-containing myrosin cells. These plants are termed MINELESS because they lack myrosin cells, the so-called toxic mustard oil mines. Here, we examined the interaction between B. napus wild-type and MINELESS plants and the larvae of the cabbage moth Mamestra brassicae. No-choice feeding experiments showed that M. brassicae larvae gained less weight and showed stunted growth when feeding on MINELESS plants compared to feeding on wild-type plants. M. brassicae feeding didn't affect myrosinase activity in MINELESS plants, but did reduce it in wild-type seedlings. M. brassicae feeding increased the levels of indol-3-yl-methyl, 1-methoxy-indol-3-yl-methyl, and total glucosinolates in both wild-type and MINELESS seedlings. M. brassicae feeding affected the levels of glucosinolate hydrolysis products in both wild-type and MINELESS plants. Transcriptional analysis showed that 494 and 159 genes were differentially regulated after M. brassicae feeding on wild-type and MINELESS seedlings, respectively. Taken together, the outcomes are very interesting in terms of analysing the role of myrosin cells and the glucosinolate-myrosinase defence system in response to a generalist cabbage moth, suggesting that similar studies with other generalist or specialist insect herbivores, including above- and below-ground herbivores, would be useful.

  12. Head capsule stacking by caterpillars: morphology complements behaviour to provide a novel defence.

    PubMed

    Low, Petah A; McArthur, Clare; Hochuli, Dieter F

    2016-01-01

    Herbivores employ a variety of chemical, behavioural and morphological defences to reduce mortality from natural enemies. In some caterpillars the head capsules of successive instars are retained and stacked on top of each other and it has been suggested that this could serve as a defence against natural enemies. We tested this hypothesis by comparing the survival of groups of the gumleaf skeletoniser Uraba lugens Walker caterpillars, allocated to one of three treatments: "-HC," where stacked head capsules were removed from all individuals, "+HC," where the caterpillars retained their stacked head capsules, and "mixed," where only half of the caterpillars in a group had their stacked head capsules removed. We found no difference in predation rate between the three treatments, but within the mixed treatment, caterpillars with head capsules were more than twice as likely to survive. During predator choice trials, conducted to observe how head capsule stacking acts as a defence, the predatory pentatomid bug attacked the -HC caterpillar in four out of six trials. The two attacks on +HC caterpillars took over 10 times longer because the bug would poke its rostrum through the head capsule stack, while the caterpillar used its head capsule stack to deflect the bug's rostrum. Our results support the hypothesis that the retention of moulted head capsules by U. lugens provides some protection against their natural enemies and suggest that this is because stacked head capsules can function as a false target for natural enemies as well as a weapon to fend off attackers. This represents the first demonstration of a defensive function.

  13. Head capsule stacking by caterpillars: morphology complements behaviour to provide a novel defence.

    PubMed

    Low, Petah A; McArthur, Clare; Hochuli, Dieter F

    2016-01-01

    Herbivores employ a variety of chemical, behavioural and morphological defences to reduce mortality from natural enemies. In some caterpillars the head capsules of successive instars are retained and stacked on top of each other and it has been suggested that this could serve as a defence against natural enemies. We tested this hypothesis by comparing the survival of groups of the gumleaf skeletoniser Uraba lugens Walker caterpillars, allocated to one of three treatments: "-HC," where stacked head capsules were removed from all individuals, "+HC," where the caterpillars retained their stacked head capsules, and "mixed," where only half of the caterpillars in a group had their stacked head capsules removed. We found no difference in predation rate between the three treatments, but within the mixed treatment, caterpillars with head capsules were more than twice as likely to survive. During predator choice trials, conducted to observe how head capsule stacking acts as a defence, the predatory pentatomid bug attacked the -HC caterpillar in four out of six trials. The two attacks on +HC caterpillars took over 10 times longer because the bug would poke its rostrum through the head capsule stack, while the caterpillar used its head capsule stack to deflect the bug's rostrum. Our results support the hypothesis that the retention of moulted head capsules by U. lugens provides some protection against their natural enemies and suggest that this is because stacked head capsules can function as a false target for natural enemies as well as a weapon to fend off attackers. This represents the first demonstration of a defensive function. PMID:26966656

  14. Plant defence responses in oilseed rape MINELESS plants after attack by the cabbage moth Mamestra brassicae

    PubMed Central

    Ahuja, Ishita; van Dam, Nicole Marie; Winge, Per; Trælnes, Marianne; Heydarova, Aysel; Rohloff, Jens; Langaas, Mette; Bones, Atle Magnar

    2015-01-01

    The Brassicaceae family is characterized by a unique defence mechanism known as the ‘glucosinolate–myrosinase’ system. When insect herbivores attack plant tissues, glucosinolates are hydrolysed by the enzyme myrosinase (EC 3.2.1.147) into a variety of degradation products, which can deter further herbivory. This process has been described as ‘the mustard oil bomb’. Additionally, insect damage induces the production of glucosinolates, myrosinase, and other defences. Brassica napus seeds have been genetically modified to remove myrosinase-containing myrosin cells. These plants are termed MINELESS because they lack myrosin cells, the so-called toxic mustard oil mines. Here, we examined the interaction between B. napus wild-type and MINELESS plants and the larvae of the cabbage moth Mamestra brassicae. No-choice feeding experiments showed that M. brassicae larvae gained less weight and showed stunted growth when feeding on MINELESS plants compared to feeding on wild-type plants. M. brassicae feeding didn’t affect myrosinase activity in MINELESS plants, but did reduce it in wild-type seedlings. M. brassicae feeding increased the levels of indol-3-yl-methyl, 1-methoxy-indol-3-yl-methyl, and total glucosinolates in both wild-type and MINELESS seedlings. M. brassicae feeding affected the levels of glucosinolate hydrolysis products in both wild-type and MINELESS plants. Transcriptional analysis showed that 494 and 159 genes were differentially regulated after M. brassicae feeding on wild-type and MINELESS seedlings, respectively. Taken together, the outcomes are very interesting in terms of analysing the role of myrosin cells and the glucosinolate–myrosinase defence system in response to a generalist cabbage moth, suggesting that similar studies with other generalist or specialist insect herbivores, including above- and below-ground herbivores, would be useful. PMID:25563968

  15. Analysis of pea HMG-I/Y expression suggests a role in defence gene regulation.

    PubMed

    Klosterman, Steven J; Choi, Jane J; Hadwiger, Lee A

    2003-07-01

    SUMMARY HMG-I/Y proteins are characterized by the presence of AT-hook motifs, DNA binding domains that recognize AT-rich tracts of DNA. By facilitating protein:protein and protein:DNA interactions in the vicinity of these AT-rich binding sites, HMG-I/Y positively or negatively regulates gene expression. Several pea defence gene promoters have AT-rich tracts of DNA that are potential targets for modulation via HMG-I/Y. In this study, a comparison of the expression of a pea defence gene (DRR206) mRNA relative to the expression of HMG-I/Y mRNA was monitored by Northern analysis following the inoculation of a fungal pathogen, Fusarium solani or treatment with chitosan and a F. solani DNase (Fsph DNase). In pea pod endocarp tissue, HMG-I/Y expression was observed at high levels in untreated tissue and at lower levels 6 h following inoculation or wounding of the tissue. Western blots with an antipea HMG-I/Y polyclonal antibody also revealed that pea HMG-I/Y is expressed at decreased levels 6 h following inoculation or elicitor treatment. HMG-I/Y extracted from pea caused alterations in the gel migration of radio-labelled AT-rich sequences from the pea DRR206 promoter, suggesting that similar interactions could exist in vivo. Agroinfiltration was utilized to express the pea HMG-I/Y gene in tobacco containing a chimeric gene fusion of a promoter from the PR gene, DRR206, and the beta-glucuronidase (GUS) reporter gene. Transient expression of pea HMG-I/Y led to a decrease in GUS reporter gene activity in the heterologous tobacco system. These data implicate pea HMG-I/Y abundance in the down-regulation of DRR206 gene expression, and possibly HMG-I/Y depletion in the expression of defence genes in pea.

  16. Head capsule stacking by caterpillars: morphology complements behaviour to provide a novel defence

    PubMed Central

    McArthur, Clare; Hochuli, Dieter F.

    2016-01-01

    Herbivores employ a variety of chemical, behavioural and morphological defences to reduce mortality from natural enemies. In some caterpillars the head capsules of successive instars are retained and stacked on top of each other and it has been suggested that this could serve as a defence against natural enemies. We tested this hypothesis by comparing the survival of groups of the gumleaf skeletoniser Uraba lugens Walker caterpillars, allocated to one of three treatments: “−HC,” where stacked head capsules were removed from all individuals, “+HC,” where the caterpillars retained their stacked head capsules, and “mixed,” where only half of the caterpillars in a group had their stacked head capsules removed. We found no difference in predation rate between the three treatments, but within the mixed treatment, caterpillars with head capsules were more than twice as likely to survive. During predator choice trials, conducted to observe how head capsule stacking acts as a defence, the predatory pentatomid bug attacked the −HC caterpillar in four out of six trials. The two attacks on +HC caterpillars took over 10 times longer because the bug would poke its rostrum through the head capsule stack, while the caterpillar used its head capsule stack to deflect the bug’s rostrum. Our results support the hypothesis that the retention of moulted head capsules by U. lugens provides some protection against their natural enemies and suggest that this is because stacked head capsules can function as a false target for natural enemies as well as a weapon to fend off attackers. This represents the first demonstration of a defensive function. PMID:26966656

  17. Glyphosate-based herbicide exposure causes antioxidant defence responses in the fruit fly Drosophila melanogaster.

    PubMed

    de Aguiar, Lais Mattos; Figueira, Fernanda Hernandes; Gottschalk, Marco Silva; da Rosa, Carlos Eduardo

    2016-01-01

    Glyphosate is a non-selective and post-emergent herbicide that affects plant growth. Animal exposure to this herbicide can lead to adverse effects, such as endocrine disruption, oxidative stress and behavioural disorders. Drosophilids have been utilized previously as an effective tool in toxicological tests. In the present study, the effects of a glyphosate-based herbicide (Roundup [Original]) were investigated regarding oxidative stress, the antioxidant defence system and acetylcholinesterase (AChE) activity in Drosophila melanogaster. Flies (of both genders) that were 1 to 3days old were exposed to different glyphosate concentrations (0.0mg/L=control, 1.0mg/L, 2.0mg/L, 5.0mg/L and 10.0mg/L) in the diet for 24h and 96h. After the exposure periods, reactive oxygen species (ROS) levels, antioxidant capacity against peroxyl radicals (ACAP) and lipid peroxidation (LPO) levels were quantified. In addition, the mRNA expression of antioxidant genes (i.e., keap1, sod, sod2, cat, irc, gclc, gclm, gss, trxt, trxr-1 and trxr-2) was evaluated via RT-PCR. Additionally, AChE activity was evaluated only after the 96h exposure period. The results indicated that Roundup exposure leads to a reduction in ROS levels in flies exposed for 96h. ACAP levels and gene expression of the antioxidant defence system exhibited an increase from 24h, while LPO did not show any significant alterations in both exposure periods. AChE activity was not affected following Roundup exposure. Our data suggest that Roundup exposure causes an early activation of the antioxidant defence system in D. melanogaster, and this can prevent subsequent damage caused by ROS.

  18. Foxp3+ regulatory T cells, immune stimulation and host defence against infection

    PubMed Central

    Rowe, Jared H; Ertelt, James M; Way, Sing Sing

    2012-01-01

    The immune system is intricately regulated allowing potent effectors to expand and become rapidly mobilized after infection, while simultaneously silencing potentially detrimental responses that averts immune-mediated damage to host tissues. This relies in large part on the delicate interplay between immune suppressive regulatory CD4+ T (Treg) cells and immune effectors that without active suppression by Treg cells cause systemic and organ-specific autoimmunity. Although these beneficial roles have been classically described as counterbalanced by impaired host defence against infection, newfound protective roles for Treg cells against specific viral pathogens (e.g. herpes simplex virus 2, lymphocytic choriomeningitis virus, West Nile virus) have been uncovered using transgenic mice that allow in vivo Treg-cell ablation based on Foxp3 expression. In turn, Foxp3+ Treg cells also provide protection against some parasitic (Plasmodium sp., Toxoplasma gondii) and fungal (Candida albicans) pathogens. By contrast, for bacterial and mycobacterial infections (e.g. Listeria monocytogenes, Salmonella enterica, Mycobacterium tuberculosis), experimental manipulation of Foxp3+ cells continues to indicate detrimental roles for Treg cells in host defence. This variance is probably related to functional plasticity in Treg cell suppression that shifts discordantly following infection with different types of pathogens. Furthermore, the efficiency whereby Treg cells silence immune activation coupled with the plasticity in Foxp3+ cell activity suggest that overriding Treg-mediated suppression represents a prerequisite ‘signal zero’ that together with other stimulation signals [T-cell receptor (signal 1), co-stimulation (signal 2), inflammatory cytokines (signal 3)] are essential for T-cell activation in vivo. Herein, the importance of Foxp3+ Treg cells in host defence against infection, and the significance of infection-induced shifts in Treg-cell suppression are summarized. PMID

  19. Gastrointestinal-Sparing Effects of Novel NSAIDs in Rats with Compromised Mucosal Defence

    PubMed Central

    Blackler, Rory; Syer, Stephanie; Bolla, Manlio; Ongini, Ennio; Wallace, John L.

    2012-01-01

    Nonsteroidal anti-inflammatory drugs are among the most commonly used prescription and over-the-counter medications, but they often produce significant gastrointestinal ulceration and bleeding, particularly in elderly patients and patients with certain co-morbidities. Novel anti-inflammatory drugs are seldom tested in animal models that mimic the high risk human users, leading to an underestimate of the true toxicity of the drugs. In the present study we examined the effects of two novel NSAIDs and two commonly used NSAIDs in models in which mucosal defence was expected to be impaired. Naproxen, celecoxib, ATB-346 (a hydrogen sulfide- and naproxen-releasing compound) and NCX 429 (a nitric oxide- and naproxen-releasing compound) were evaluated in healthy, arthritic, obese, and hypertensive rats and in rats of advanced age (19 months) and rats co-administered low-dose aspirin and/or omeprazole. In all models except hypertension, greater gastric and/or intestinal damage was observed when naproxen was administered in these models than in healthy rats. Celecoxib-induced damage was significantly increased when co-administered with low-dose aspirin and/or omeprazole. In contrast, ATB-346 and NCX 429, when tested at doses that were as effective as naproxen and celecoxib in reducing inflammation and inhibiting cyclooxygenase activity, did not produce significant gastric or intestinal damage in any of the models. These results demonstrate that animal models of human co-morbidities display the same increased susceptibility to NSAID-induced gastrointestinal damage as observed in humans. Moreover, two novel NSAIDs that release mediators of mucosal defence (hydrogen sulfide and nitric oxide) do not induce significant gastrointestinal damage in these models of impaired mucosal defence. PMID:22496907

  20. Effect of Fusarium virguliforme phytotoxin on soybean gene expression suggests a role in multidimensional defence.

    PubMed

    Radwan, Osman; Li, Min; Calla, Bernarda; Li, Shuxian; Hartman, Glen L; Clough, Steven J

    2013-04-01

    Sudden death syndrome (SDS), caused by Fusarium virguliforme, is an important yield-limiting disease of soybean. This soil-borne fungus colonizes soybean roots causing root rot, and also releases a phytotoxin that is translocated to leaves causing interveinal chlorosis and necrosis leading to defoliation and early maturation. The objective of our study was to compare gene expression profiles during the early response of soybean leaves exposed to sterile culture filtrates of F. virguliforme in soybean genotypes with different levels of resistance to SDS. The analysis identified SDS-related defence genes that were induced in the most resistant genotype, but not in the other genotypes. Further functional annotations based on sequence homology suggested that some of the induced genes probably encode proteins involved in cell wall modification, detoxification, defence responses, primary metabolism and membrane transport. Quantitative real-time reverse-transcribed polymerase chain reaction confirmed the differential transcript accumulation of a subset of these genes. In addition, in silico mapping of differentially expressed genes to SDS-resistant quantitative trait loci allowed for the identification of new potential defence genes that could be genetically mapped to the soybean genome, and could be used further in a marker-assisted selection programme. A comparison of the response of soybean to F. virguliforme phytotoxin (Fv toxin) relative to other biotic and abiotic stresses revealed that the resistance response to Fv toxin is quite similar to the response to inoculation with an incompatible Pseudomonas syringae pv. glycinea strain, suggesting that Fv toxin might induce hypersensitive response pathways in soybean leaf tissues in the absence of pathogen in these tissues. PMID:23240728

  1. Stability precision dynamic testing system on artillery

    NASA Astrophysics Data System (ADS)

    Wang, Chunyan; Li, Bo

    2014-12-01

    Dynamic feature of Weapon equipments is one of important performance index for evaluating the performance of the whole weapon system. The construction of target range in our country in fire control dynamic testing is relatively backward; therefore, it has greatly influenced the evaluation on the fire control system. In order to solve this problem, it's urgent to develop a new testing instrument so as to adjust to the armament research process and promote weapon system working more efficiently and thereby meeting the needs of modernization in national defense. This paper proposes a new measure which is used to test the stability precision of the fire control system, and it is installed on the moving base. Using the method, we develop a testing system which can test the stability precision of the fire control system and achieve a high precision results after testing. The innovation of the system is we can receive the image not only by CCD, but our eyes. It also adopts digital image-forming and image processing technique for real-time measurement and storing of the target information; it simultaneously adopts the method adjusting the platform and the corresponding fixture mounted on a sample to measure the stable precision and the precision of corner of stabilizator. In this paper, we make a description on the construction of the system and the idea of the designing of the optical system. Finally, we introduce the actual application of the system and testing results.

  2. The SnoDog: Preliminary design of a close air support aircraft

    NASA Technical Reports Server (NTRS)

    Ashbaugh, Scott; Bartel, Kent; Cavalli, J. R.; Chan, John; Chung, Jason; Dimaranan, Liza; Freese, Mike; Levitt, Rick; Soban, Dani

    1991-01-01

    U.S. military forces are presently searching for the next generation Close Air Support aircraft. The following report presents the SnoDog, a low-cost ($14.8 million) aircraft capable of operating from remote battlefields and unimproved airstrips. The configuration consists of a conventional, low aspect-ratio wing, twin booms, twin canted vertical stabilizers along with a high-mounted joined horizontal tail. A supercritical airfoil for the wing enhances aerodynamic performance, while the SnoDog's instability increases maneuverability over current close air support aircraft. Survivability was incorporated into the design by the use of a titanium tub to protect the cockpit from anti-aircraft artillery, as well as, the twin booms and retracted gear disposition. The booms aid survivability by supplying separated, redundant controls, and the landing gear are slightly exposed when retracted to enable a belly landing in emergencies. Designed to fly at Mach .76, the SnoDog is powered by two low-bypass turbofan engines. Engine accessibility and interchangeable parts make the SnoDog highly maintainable. The SnoDog is adaptable to many different missions, as it is capable of carrying advanced avionics pods, carrying external fuel tanks or refueling in-air, and carrying various types of munitions. This makes the SnoDog a multirole aircraft capable of air-to-air and air-to-ground combat. This combination of features make the SnoDog unique as a close air support aircraft, capable of meeting the U.S. military's future needs.

  3. Residential housing and nuclear attack: The ineffectiveness of current civil defence measures

    SciTech Connect

    Diacon, D.

    1985-01-01

    Diane Diacon of the Building and Social Housing Foundation has conducted an independent investigation of the question, and in this book she sums up the results. She first examines the nature of nuclear attack, and then goes on to explore the usefulness of specially-designed nuclear shelters and the likely disruption of essential services in the case of war. She concludes that the protection afforded by residential housing is in fact extremely poor, and that the civil defence measures contemplated by government bureaucrats are likely to be utterly ineffective.

  4. Advances in AlGaInN laser diode technology for defence and sensing applications

    NASA Astrophysics Data System (ADS)

    Najda, S. P.; Perlin, P.; Suski, T.; Marona, L.; Boćkowski, M.; Leszczyński, M.; Wisniewski, P.; Czernecki, R.; Kucharski, R.; Targowski, G.

    2016-05-01

    Laser diodes fabricated from the AlGaInN material system is an emerging technology for defence and security applications. The AlGaInN material system allows for laser diodes to be fabricated over a very wide range of wavelengths from u.v., ~380nm, to the visible ~530nm, by tuning the indium content of the laser GaInN quantum well, giving rise to new and novel applications including displays and imaging systems, atomic clock and quantum information, free-space and underwater telecom and lidar.

  5. Crime, psychiatry and the insanity defence: a report on some recent reforms in the United States.

    PubMed

    Brakel, S J; Cavanaugh, J L

    1996-02-01

    There have been substantial developments in mental health law in the United States over the last 10-15 years. Once focal point has been the insanity defence, discussed here. The operational consequences of the legal changes remain to be assessed empirically, but informed speculation is possible. Both a description of the reforms and the assessment of their potential effect are relevant to members of the psychiatric profession in Australia, whether they be forensic specialists or traditional practitioners or researchers. Selective consideration of the American experience, as opposed to contemplating Wholesale transposition, is the appropriate posture for Australian policymakers.

  6. Automating patient safety incident reporting to improve healthcare quality in the defence medical services.

    PubMed

    Lamb, Di; Piper, N

    2015-12-01

    There are many reasons for poor compliance with patient safety incident reporting in the UK. The Defence Medical Services has made a significant investment to address the culture and process by which risk to patient safety is managed within its organisation. This paper describes the decision process and technical considerations in the design of an automated reporting system together with the implementation procedure aimed to maximise compliance. The elimination of inherent weaknesses in feedback mechanisms from the three Armed Forces, which had been uniquely different, ensured the quality of data improved, which enabled resources to be prioritised that would also have a direct impact upon the quality of patient care.

  7. Host defence against Candida albicans and the role of pattern-recognition receptors.

    PubMed

    Gauglitz, Gerd G; Callenberg, Helene; Weindl, Günther; Korting, Hans C

    2012-05-01

    Recognition of Candida albicans is mediated by several classes of pattern-recognition receptors, including Toll-like receptors and C-type lectin receptors. Cell wall components of C. albicans, interact with the pattern-recognition receptors, which are expressed by different cells, primarily antigen-presenting cells. This review aims to discuss the different pattern-recognition receptors responsible for recognition of special structures of C. albicans, which are known to activate intracellular signals that finally lead to directed and efficient host defence.

  8. Therapeutic Approaches Using Host Defence Peptides to Tackle Herpes Virus Infections

    PubMed Central

    Jenssen, Håvard

    2009-01-01

    One of the most common viral infections in humans is caused by herpes simplex virus (HSV). It can easily be treated with nucleoside analogues (e.g., acyclovir), but resistant strains are on the rise. Naturally occurring antimicrobial peptides have been demonstrated to possess antiviral activity against HSV. New evidence has also indicated that these host defence peptides are able to selectively stimulate the innate immune system to fight of infections. This review will focus on the anti-HSV activity of such peptides (both natural and synthetic), describe their mode of action and their clinical potential. PMID:21994576

  9. Latent tuberculosis infection (LTBI): a real host defence or a permanent threat?

    PubMed

    Sanduzzi, Alessandro; Ponticiello, Antonio; Bocchino, Marialuisa; Perna, Francesco; Vatrella, Alessandro

    2016-09-01

    Screening of latent infection by Mycobacterium tuberculosis (LTBI) and treatment of positive subjects is the key point in the prevention of TB; such a strategy should be performed mainly among individuals with risk of progression. Progression from LTBI to active TB is highest both in recent contacts of patients with active TB, and in immunocompromised subjects. Therefore, LTBI could either be considered a permanent host defence or, seen from the opposite point of view, it could represent a long-lasting threat if the efficiency of the immune system declines over a lifetime. Interferon gamma release assays (IGRAs) show better sensitivity and specificity than the Mantoux test. PMID:27668896

  10. Air resources

    SciTech Connect

    1995-10-01

    This section describes the ambient (surrounding) air quality of the TVA region, discusses TVA emission contributions to ambient air quality, and identifies air quality impacts to human health and welfare. Volume 2 Technical Document 2, Environmental Consequences, describes how changes in TVA emissions could affect regional air quality, human health, environmental resources, and materials. The primary region of the affected environment is broadly defined as the state of Tennessee, as well as southern Kentucky, western Virginia, southern West Virginia, western North Carolina, and northern Georgia, Alabama, and Mississippi. This area represents the watershed of the Tennessee River and the 201 counties of the greater TVA service area. Emissions from outside the Tennessee Valley region contribute to air quality in the Valley. Also, TVA emissions are transported outside the Valley and have some impact on air quality beyond the primary study area. Although the study area experiences a number of air quality problems, overall air quality is good.

  11. Role of stress-related hormones in plant defence during early infection of the cyst nematode Heterodera schachtii in Arabidopsis.

    PubMed

    Kammerhofer, Nina; Radakovic, Zoran; Regis, Jully M A; Dobrev, Petre; Vankova, Radomira; Grundler, Florian M W; Siddique, Shahid; Hofmann, Julia; Wieczorek, Krzysztof

    2015-08-01

    Heterodera schachtii, a plant-parasitic cyst nematode, invades host roots and induces a specific syncytial feeding structure, from which it withdraws all required nutrients, causing severe yield losses. The system H. schachtii-Arabidopsis is an excellent research model for investigating plant defence mechanisms. Such responses are suppressed in well-established syncytia, whereas they are induced during early parasitism. However, the mechanisms by which the defence responses are modulated and the role of phytohormones are largely unknown. The aim of this study was to elucidate the role of hormone-based defence responses at the onset of nematode infection. First, concentrations of main phytohormones were quantified and the expression of several hormone-related genes was analysed using quantitative real-time (qRT)-PCR or GeneChip. Further, the effects of individual hormones were evaluated via nematode attraction and infection assays using plants with altered endogenous hormone concentrations. Our results suggest a pivotal and positive role for ethylene during nematode attraction, whereas jasmonic acid triggers early defence responses against H. schachtii. Salicylic acid seems to be a negative regulator during later syncytium and female development. We conclude that nematodes are able to impose specific changes in hormone pools, thus modulating hormone-based defence and signal transduction in strict dependence on their parasitism stage.

  12. Role of stress-related hormones in plant defence during early infection of the cyst nematode Heterodera schachtii in Arabidopsis

    PubMed Central

    Kammerhofer, Nina; Radakovic, Zoran; Regis, Jully M A; Dobrev, Petre; Vankova, Radomira; Grundler, Florian M W; Siddique, Shahid; Hofmann, Julia; Wieczorek, Krzysztof

    2015-01-01

    Heterodera schachtii, a plant-parasitic cyst nematode, invades host roots and induces a specific syncytial feeding structure, from which it withdraws all required nutrients, causing severe yield losses. The system H. schachtii–Arabidopsis is an excellent research model for investigating plant defence mechanisms. Such responses are suppressed in well-established syncytia, whereas they are induced during early parasitism. However, the mechanisms by which the defence responses are modulated and the role of phytohormones are largely unknown. The aim of this study was to elucidate the role of hormone-based defence responses at the onset of nematode infection. First, concentrations of main phytohormones were quantified and the expression of several hormone-related genes was analysed using quantitative real-time (qRT)-PCR or GeneChip. Further, the effects of individual hormones were evaluated via nematode attraction and infection assays using plants with altered endogenous hormone concentrations. Our results suggest a pivotal and positive role for ethylene during nematode attraction, whereas jasmonic acid triggers early defence responses against H. schachtii. Salicylic acid seems to be a negative regulator during later syncytium and female development. We conclude that nematodes are able to impose specific changes in hormone pools, thus modulating hormone-based defence and signal transduction in strict dependence on their parasitism stage. PMID:25825039

  13. [Hi-tech health care: modern status and prospects of development in medical facilities of the Ministry of Defence].

    PubMed

    Fisun, A Ia; Kuvshinov, K É; Makiev, R G; Pastukhov, A G

    2014-02-01

    The article is devoted to the current issues of providing hi-tech medical care in hospitals of the Ministry of Defence. Since the beginning of 2013 the executive body of the Russian Ministry of Defense pays special attention to improvement of the quality and accessibility of health care contingent of the Ministry of Defence. Thus, according to decision of the Minister of Defense of the Russian Federation, General of the Army Sergei Shoigu in 2013 more than 1.1 billion rubles (in 2012, targeted funding of high-tech medical care in the Ministry of Defence did not materialize) was allocated for military medical institutions of the Ministry of Defense of the Russian Federation to provide high-tech medical care. As a result, in 7 months in 2013 the volume of medical care has increased by 32% in comparison with the same period in 2012. Currently the main military medical department of the Ministry of Defense is working to resolve the order of delivery and financing hi-tech medical care in the Armed Forces in the following areas: inclusion of military medical institutions of the Ministry of Defence in the list of health organizations, providing high-tech medical care, approved by Order of the Ministry of Health of the Russian Federation, legal regulation of the provision of high-tech medical care in military medical establishments of the Ministry of defense of the Russian Federation within the budget appropriation allocated to the Ministry of Defence. PMID:25046918

  14. On the study of plant defence and herbivory using comparative approaches: how important are secondary plant compounds.

    PubMed

    Agrawal, Anurag A; Weber, Marjorie G

    2015-10-01

    Species comparisons are a cornerstone of biology and there is a long tradition of using the comparative framework to study the ecology and evolution of plant defensive traits. Early comparative studies led to the hypothesis that plant chemistry plays a central role in plant defence, and the evolution of plant secondary chemistry in response to insect herbivory remains a classic example of coevolution. However, recent comparative work has disagreed with this paradigm, reporting little connection between plant secondary chemicals and herbivory across distantly related plant taxa. One conclusion of this new work is that the importance of secondary chemistry in plant defence may have been generally overstated in earlier research. Here, we attempt to reconcile these contradicting viewpoints on the role of plant chemistry in defence by critically evaluating the use and interpretation of species correlations as a means to study defence-herbivory relationships. We conclude that the notion that plant primary metabolites (e.g. leaf nitrogen content) are the principal determinants of herbivory (or the target of natural selection by herbivores) is not likely to be correct. Despite the inference of recent community-wide studies of herbivory, strong evidence remains for a prime role of secondary compounds in plant defence against herbivores.

  15. Functional inactivation of UDP-N-acetylglucosamine pyrophosphorylase 1 (UAP1) induces early leaf senescence and defence responses in rice.

    PubMed

    Wang, Zhaohai; Wang, Ya; Hong, Xiao; Hu, Daoheng; Liu, Caixiang; Yang, Jing; Li, Yang; Huang, Yunqing; Feng, Yuqi; Gong, Hanyu; Li, Yang; Fang, Gen; Tang, Huiru; Li, Yangsheng

    2015-02-01

    Plant leaf senescence and defence responses are important biological processes, but the molecular mechanisms involved are not well understood. This study identified a new rice mutant, spotted leaf 29 (spl29). The SPL29 gene was identified by map-based cloning, and SPL29 was confirmed as UDP-N-acetylglucosamine pyrophosphorylase 1 (UAP1) by enzymatic analysis. The mutant spl29 lacks UAP activity. The biological phenotypes for which UAP is responsible have not previously been reported in plants. The spl29 mutant displayed early leaf senescence, confirmed by chlorophyll loss and photosystem II decline as physiological indicators, chloroplast degradation as a cellular characteristic, and both upregulation of senescence transcription factors and senescence-associated genes, and downregulation of photosynthesis-related genes, as molecular evidence. Defence responses were induced in the spl29 mutant, shown by enhanced resistance to bacterial blight inoculation and upregulation of defence response genes. Reactive oxygen species, including O2 (-) and H2O2, accumulated in spl29 plants; there was also increased malondialdehyde content. Enhanced superoxide dismutase activity combined with normal catalase activity in spl29 could be responsible for H2O2 accumulation. The plant hormones jasmonic acid and abscisic acid also accumulated in spl29 plants. ROS and plant hormones probably play important roles in early leaf senescence and defence responses in the spl29 mutant. Based on these findings, it is suggested that UAP1 is involved in regulating leaf senescence and defence responses in rice. PMID:25399020

  16. [Hi-tech health care: modern status and prospects of development in medical facilities of the Ministry of Defence].

    PubMed

    Fisun, A Ia; Kuvshinov, K É; Makiev, R G; Pastukhov, A G

    2014-02-01

    The article is devoted to the current issues of providing hi-tech medical care in hospitals of the Ministry of Defence. Since the beginning of 2013 the executive body of the Russian Ministry of Defense pays special attention to improvement of the quality and accessibility of health care contingent of the Ministry of Defence. Thus, according to decision of the Minister of Defense of the Russian Federation, General of the Army Sergei Shoigu in 2013 more than 1.1 billion rubles (in 2012, targeted funding of high-tech medical care in the Ministry of Defence did not materialize) was allocated for military medical institutions of the Ministry of Defense of the Russian Federation to provide high-tech medical care. As a result, in 7 months in 2013 the volume of medical care has increased by 32% in comparison with the same period in 2012. Currently the main military medical department of the Ministry of Defense is working to resolve the order of delivery and financing hi-tech medical care in the Armed Forces in the following areas: inclusion of military medical institutions of the Ministry of Defence in the list of health organizations, providing high-tech medical care, approved by Order of the Ministry of Health of the Russian Federation, legal regulation of the provision of high-tech medical care in military medical establishments of the Ministry of defense of the Russian Federation within the budget appropriation allocated to the Ministry of Defence.

  17. An Overview of Seasonal Changes in Oxidative Stress and Antioxidant Defence Parameters in Some Invertebrate and Vertebrate Species.

    PubMed

    Chainy, Gagan Bihari Nityananda; Paital, Biswaranjan; Dandapat, Jagneswar

    2016-01-01

    Antioxidant defence system, a highly conserved biochemical mechanism, protects organisms from harmful effects of reactive oxygen species (ROS), a by-product of metabolism. Both invertebrates and vertebrates are unable to modify environmental physical factors such as photoperiod, temperature, salinity, humidity, oxygen content, and food availability as per their requirement. Therefore, they have evolved mechanisms to modulate their metabolic pathways to cope their physiology with changing environmental challenges for survival. Antioxidant defences are one of such biochemical mechanisms. At low concentration, ROS regulates several physiological processes, whereas at higher concentration they are toxic to organisms because they impair cellular functions by oxidizing biomolecules. Seasonal changes in antioxidant defences make species able to maintain their correct ROS titre to take various physiological functions such as hibernation, aestivation, migration, and reproduction against changing environmental physical parameters. In this paper, we have compiled information available in the literature on seasonal variation in antioxidant defence system in various species of invertebrates and vertebrates. The primary objective was to understand the relationship between varied biological phenomena seen in different animal species and conserved antioxidant defence system with respect to seasons. PMID:27127682

  18. Developments in aspects of ecological phytochemistry: the role of cis-jasmone in inducible defence systems in plants.

    PubMed

    Pickett, John A; Birkett, Michael A; Bruce, Toby J A; Chamberlain, Keith; Gordon-Weeks, Ruth; Matthes, Michaela C; Napier, Johnathan A; Smart, Lesley E; Woodcock, Christine M

    2007-01-01

    The challenges and opportunities for protecting agricultural production of food and other materials will be met through exploiting the induction of defence pathways in plants to control pests, diseases and weeds. These approaches will involve processes that can be activated by application of natural products, patented in terms of this use, to "switch on" defence pathways. Already, a number of secondary metabolite defence compounds are known for which the pathways are conveniently clustered genomically, e.g. the benzoxazinoids (hydroxamic acids) and the avenacins. For the former, it is shown that the small molecular weight lipophilic activator cis-jasmone can induce production of these compounds and certain genes within the pathway. Numerous groups around the world work on inducible defence systems. The science is rapidly expanding and involves studying the interacting components of defence pathways and the switching mechanisms activated by small molecular weight lipophilic compounds. Examples are described of how plant breeding can exploit these systems and how heterologous gene expression will eventually give rise to a new range of GM crops for food and energy, without the need for external application of synthetic pesticides. PMID:18023830

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

    PubMed

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

    2013-08-01

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

  20. An Overview of Seasonal Changes in Oxidative Stress and Antioxidant Defence Parameters in Some Invertebrate and Vertebrate Species

    PubMed Central

    Chainy, Gagan Bihari Nityananda; Paital, Biswaranjan; Dandapat, Jagneswar

    2016-01-01

    Antioxidant defence system, a highly conserved biochemical mechanism, protects organisms from harmful effects of reactive oxygen species (ROS), a by-product of metabolism. Both invertebrates and vertebrates are unable to modify environmental physical factors such as photoperiod, temperature, salinity, humidity, oxygen content, and food availability as per their requirement. Therefore, they have evolved mechanisms to modulate their metabolic pathways to cope their physiology with changing environmental challenges for survival. Antioxidant defences are one of such biochemical mechanisms. At low concentration, ROS regulates several physiological processes, whereas at higher concentration they are toxic to organisms because they impair cellular functions by oxidizing biomolecules. Seasonal changes in antioxidant defences make species able to maintain their correct ROS titre to take various physiological functions such as hibernation, aestivation, migration, and reproduction against changing environmental physical parameters. In this paper, we have compiled information available in the literature on seasonal variation in antioxidant defence system in various species of invertebrates and vertebrates. The primary objective was to understand the relationship between varied biological phenomena seen in different animal species and conserved antioxidant defence system with respect to seasons. PMID:27127682

  1. Developments in aspects of ecological phytochemistry: the role of cis-jasmone in inducible defence systems in plants.

    PubMed

    Pickett, John A; Birkett, Michael A; Bruce, Toby J A; Chamberlain, Keith; Gordon-Weeks, Ruth; Matthes, Michaela C; Napier, Johnathan A; Smart, Lesley E; Woodcock, Christine M

    2007-01-01

    The challenges and opportunities for protecting agricultural production of food and other materials will be met through exploiting the induction of defence pathways in plants to control pests, diseases and weeds. These approaches will involve processes that can be activated by application of natural products, patented in terms of this use, to "switch on" defence pathways. Already, a number of secondary metabolite defence compounds are known for which the pathways are conveniently clustered genomically, e.g. the benzoxazinoids (hydroxamic acids) and the avenacins. For the former, it is shown that the small molecular weight lipophilic activator cis-jasmone can induce production of these compounds and certain genes within the pathway. Numerous groups around the world work on inducible defence systems. The science is rapidly expanding and involves studying the interacting components of defence pathways and the switching mechanisms activated by small molecular weight lipophilic compounds. Examples are described of how plant breeding can exploit these systems and how heterologous gene expression will eventually give rise to a new range of GM crops for food and energy, without the need for external application of synthetic pesticides.

  2. Air Pollution.

    ERIC Educational Resources Information Center

    Gilpin, Alan

    A summary of one of our most pressing environmental problems, air pollution, is offered in this book by the Director of Air Pollution Control for the Queensland (Australia) State Government. Discussion of the subject is not restricted to Queensland or Australian problems and policies, however, but includes analysis of air pollution the world over.…

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

    PubMed

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

    2016-07-21

    Group 3 innate lymphoid cells (ILC3) are major regulators of inflammation and infection at mucosal barriers. ILC3 development is thought to be programmed, but how ILC3 perceive, integrate and respond to local environmental signals remains unclear. Here we show that ILC3 in mice sense their environment and control gut defence as part of a glial–ILC3–epithelial cell unit orchestrated by neurotrophic factors. We found that enteric ILC3 express the neuroregulatory receptor RET. ILC3-autonomous Ret ablation led to decreased innate interleukin-22 (IL-22), impaired epithelial reactivity, dysbiosis and increased susceptibility to bowel inflammation and infection. Neurotrophic factors directly controlled innate Il22 downstream of the p38 MAPK/ERK-AKT cascade and STAT3 activation. Notably, ILC3 were adjacent to neurotrophic-factor-expressing glial cells that exhibited stellate-shaped projections into ILC3 aggregates. Glial cells sensed microenvironmental cues in a MYD88-dependent manner to control neurotrophic factors and innate IL-22. Accordingly, glial-intrinsic Myd88 deletion led to impaired production of ILC3-derived IL-22 and a pronounced propensity towards gut inflammation and infection. Our work sheds light on a novel multi-tissue defence unit, revealing that glial cells are central hubs of neuron and innate immune regulation by neurotrophic factor signals. PMID:27409807

  4. Allocation of nitrogen to chemical defence and plant functional traits is constrained by soil N.

    PubMed

    Simon, Judy; Gleadow, Roslyn M; Woodrow, Ian E

    2010-09-01

    Plants have evolved a vast array of defence mechanisms to avoid or minimize damage caused by herbivores and pathogens. The costs and benefits of defences are thought to vary with the availability of resources, herbivore pressure and plant functional traits. We investigated the resource (nitrogen) and growth cost of deploying cyanogenic glycosides in seedlings of Eucalyptus cladocalyx (Myrtaceae). To do this, we grew the plants under a range of soil N conditions, from levels that were limiting for growth to those that were saturating for growth, and we measured correlations between foliar chemical and performance attributes. Within each N treatment, we found evidence that, for every N invested in cyanogenic glycosides, additional N is added to the leaf. For the lowest N treatment, the additional N was less than one per cyanogenic glycoside, rising to some two Ns for the other treatments. The interaction between cyanogenic glycosides and both condensed tannins and total phenolic compounds was also examined, but we did not detect correlations between these compounds under constant leaf N concentrations. Finally, we did not detect a correlation between net assimilation rate, relative growth rate and cyanogenic glycoside concentrations under any soil N treatment. We conclude that the growth cost of cyanogenic glycosides was likely too low to detect and that it was offset to some degree by additional N that was allocated alongside the cyanogenic glycosides.

  5. Antimicrobial peptides present in mammalian skin and gut are multifunctional defence molecules.

    PubMed

    Metz-Boutigue, Marie-Hélène; Shooshtarizadeh, Peiman; Prevost, Gilles; Haikel, Youssef; Chich, Jean-François

    2010-01-01

    Antimicrobial peptides are major components of the innate immune defence. They are well conserved along evolution, non-toxic and they ensure potent defences against a large number of pathogens. They act by direct killing of microorganisms and they possess additional roles in the regulation of adaptive immune responses, by recruting or stimulating immune cells. Skin and gut are positioned at the interface of internal milieu and external environment. They represent a physical and chemical barrier against pathogens invasion and the antimicrobial peptides limit pathogen growth in normal conditions. During infection or injury, some of these peptides are overexpressed and disrupt microbial membranes and/or stimulate immune cell recruitment, allowing to return to homeostasis or to increase inflammation. Antimicrobial peptides expression is altered in several diseases: alpha-defensins deficiency is related with Crohn's disease and in skin, cathelicidin LL-37 and beta-defensin-2 are overexpressed in psoriasis, while in atopic dermatitis, their expression is decreased. The present review provides an up-to-date summary of the expression and the biological roles of the antimicrobial peptides found in the skin and gastrointestinal mucosa of the host, in normal and pathological conditions. The involvement of these natural antimicrobial peptides in inflammation, is also discussed.

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

    PubMed

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

    2016-04-01

    Plants have evolved many strategies to protect themselves from attack, including peptide toxins that are ribosomally synthesized and thus adaptable directly by genetic polymorphisms. Certain toxins in Clitoria ternatea (butterfly pea) are cyclic cystine-knot peptides of c. 30 residues, called cyclotides, which have co-opted the plant's albumin-1 gene family for their production. How butterfly pea albumin-1 genes were commandeered and how these cyclotides are utilized in defence remain unclear. The role of cyclotides in host plant ecology and biotechnological applications requires exploration. We characterized the sequence diversity and expression dynamics of precursor and processing proteins implicated in butterfly pea cyclotide biosynthesis by expression profiling through RNA-sequencing (RNA-seq). Peptide-enriched extracts from various organs were tested for activity against insect-like membranes and the model nematode Caenorhabditis elegans. We found that the evolution and deployment of cyclotides involved their diversification to exhibit different chemical properties and expression between organs facing different defensive challenges. Cyclotide-enriched fractions from soil-contacting organs were effective at killing nematodes, whereas similar enriched fractions from aerial organs contained cyclotides that exhibited stronger interactions with insect-like membrane lipids. Cyclotides are employed as versatile and combinatorial mediators of defence in C. ternatea and have specialized to affect different classes of attacking organisms. PMID:26668107

  7. Caterpillar saliva interferes with induced Arabidopsis thaliana defence responses via the systemic acquired resistance pathway

    PubMed Central

    Weech, Marie-Hélène; Chapleau, Mélanie; Pan, Li; Ide, Christine; Bede, Jacqueline C.

    2008-01-01

    Arabidopsis thaliana (L.) Heynh. genotypes limited in their ability to mount either octadecanoid-dependent induced resistance (IR–) or systemic acquired resistance (SAR–) were used to characterize the roles of these pathways in plant–herbivore interactions. Molecular and biochemical markers of IR were analysed in plants subject to herbivory by caterpillars of the beet armyworm, Spodoptera exigua Hübner, which had either intact or impaired salivary secretions since salivary enzymes, such as glucose oxidase, have been implicated in the ability of caterpillars to circumvent induced plant defences. Transcript expression of genes encoding laccase-like multicopper oxidase [AtLMCO4 (polyphenol oxidase)] and defensin (AtPDF1.2) showed salivary-specific patterns which were disrupted in the SAR– mutant plants. The activity of octadecanoid-associated anti-nutritive proteins, such as LMCO and trypsin inhibitor, showed similar patterns. Gene and protein changes parallel plant hormone levels where elevated jasmonic acid was observed in wild-type plants fed upon by caterpillars with impaired salivary secretions compared with plants subject to herbivory by normal caterpillars. This salivary-specific difference in jasmonic acid levels was alleviated in SAR– mutants. These results support the model that caterpillar saliva interferes with jasmonate-dependent plant defences by activating the SAR pathway. PMID:18487634

  8. Lepidopteran defence droplets - a composite physical and chemical weapon against potential predators

    PubMed Central

    Pentzold, Stefan; Zagrobelny, Mika; Khakimov, Bekzod; Engelsen, Søren Balling; Clausen, Henrik; Petersen, Bent Larsen; Borch, Jonas; Møller, Birger Lindberg; Bak, Søren

    2016-01-01

    Insects often release noxious substances for their defence. Larvae of Zygaena filipendulae (Lepidoptera) secrete viscous and cyanogenic glucoside-containing droplets, whose effectiveness was associated with their physical and chemical properties. The droplets glued mandibles and legs of potential predators together and immobilised them. Droplets were characterised by a matrix of an aqueous solution of glycine-rich peptides (H-WG11-NH2) with significant amounts of proteins and glucose. Among the proteins, defensive proteins such as protease inhibitors, proteases and oxidases were abundant. The neurotoxin β-cyanoalanine was also found in the droplets. Despite the presence of cyanogenic glucosides, which release toxic hydrogen cyanide after hydrolysis by a specific β-glucosidase, the only β-glucosidase identified in the droplets (ZfBGD1) was inactive against cyanogenic glucosides. Accordingly, droplets did not release hydrogen cyanide, unless they were mixed with specific β-glucosidases present in the Zygaena haemolymph. Droplets secreted onto the cuticle hardened and formed sharp crystalline-like precipitates that may act as mandible abrasives to chewing predators. Hardening followed water evaporation and formation of antiparallel β-sheets of the peptide oligomers. Consequently, after mild irritation, Zygaena larvae deter predators by viscous and hardening droplets that contain defence proteins and β-cyanoalanine. After severe injury, droplets may mix with exuding haemolymph to release hydrogen cyanide. PMID:26940001

  9. Introduced predator elicits deficient brood defence behaviour in a crater lake fish.

    PubMed

    Lehtonen, Topi K; McCrary, Jeffrey K; Meyer, Axel

    2012-01-01

    Introduced species represent one of the most serious global threats to biodiversity. In this field-based study, we assessed behavioural responses of brood tending cichlid fish to an invasive predator of their offspring. This was achieved by comparing parental defence responses of the endangered arrow cichlid (Amphilophus zaliosus), a fish species endemic to the crater lake Apoyo in Nicaragua, towards the bigmouth sleeper (Gobiomorus dormitor), a formidable predator of cichlid fry, and all other potential fish predators of offspring. The bigmouth sleeper was recently introduced into Apoyo but naturally co-exists with cichlids in a few other Nicaraguan lakes. Arrow cichlid parents allowed bigmouth sleepers to advance much closer to their fry than other predators before initiating aggressive brood defence behaviours. Interestingly, parents of a very closely related species, A. sagittae, which has coevolved with bigmouth sleepers in crater lake Xiloá, reacted to approaching bigmouth sleepers at comparable distances as to other predators of cichlid fry. These results provide a novel demonstration of the specific mechanism (i.e. naive parental behaviour) by which invasive predators may negatively affect species that lack the adequate behavioural repertoire.

  10. Optimal design of snow avalanche passive defence structure using reliability approach to quantify buildings vulnerability

    NASA Astrophysics Data System (ADS)

    Favier, P.; Bertrand, D.; Eckert, N.; Naaim, M.

    2012-04-01

    To protect elements at risk (humans, roads, houses, etc.) against snow avalanches, civil engineering structures, such as dams or mounds, are used. The design of such defence structures is done following a deterministic approach which considers European regulation. The minimization of expected total losses is an interesting alternative that generalizes cost-benefit approach to a continuous decision variable. For this purpose, not only the hazard magnitude but also the buildings vulnerability must be evaluated carefully. The aim of this work is therefore to combine state of the art sub-models for the probabilistic description of avalanche flows and the numerical evaluation of damages to buildings. We defined the risk as the expectation of the cost consequences of avalanches activity. Disposal consequences are quantified thanks to reliability methods. In this formulation, the accuracy of both the hazard estimation and the vulnerability calculation has to be consistent according to precision and computational costs. To do so, a numerical approach has been developed to evaluate the physical vulnerability of concrete buildings submitted to avalanche loadings. The ensuing application illustrates our approach. A reinforced concrete slab is considered to model the building with a finite element method. Reliability approach enables to produce a response spectrum of the structure against avalanche impact. Finally, vulnerability curves are built. Outcomes of the risk calculation are examined to find sensitivity on the optimal design of snow defence structures.

  11. Individual contributions to territory defence in a cooperative breeder: weighing up the benefits and costs

    PubMed Central

    Mares, Rafael; Young, Andrew J.; Clutton-Brock, Tim H.

    2012-01-01

    While investment in territory defence is expected to be influenced by its benefits, the additional role that costs may play is rarely considered. Here, we quantify both benefits and costs of repelling prospecting males in cooperative meerkats, and demonstrate that both are required to explain the substantial variation in individual contributions to the defence observed. Males benefit more from repelling prospectors than females, as males may lose dominance and be expelled during intrusions. Accordingly, males invest the most in repelling prospectors. We also show that males experience an associated cost in the form of reduced weight gain and, as such, heavier males contribute more to chasing prospectors. Finally, we show evidence of a cost not restricted to individuals engaged in chasing: both males and females reduce their contributions to feeding dependent pups when prospectors are present, resulting in a reduction in pup weight gain in this context. Males appear to adjust their contributions to chasing in light of this cost, chasing at lower rates when their group contains dependent young. Our findings support the view that investment in cooperative behaviours can be attributed to benefits and costs, and highlight the additional importance of considering trade-offs in investment between cooperative behaviours. PMID:22810429

  12. Ovine trophoblasts express cathelicidin host defence peptide in response to infection.

    PubMed

    Coyle, Christopher; Wheelhouse, Nick; Jacques, Maxime; Longbottom, David; Svoboda, Pavel; Pohl, Jan; Duncan, W Colin; Rae, Michael T; Barlow, Peter G

    2016-09-01

    Cationic host defence peptides (CHDP; also known as antimicrobial peptides) are key components of the immune response in the female reproductive tract. The role of the placental trophoblast in ovine host defence remains poorly understood. This study characterises expression of genes for cathelicidin and defensin peptides in primary ovine placental tissues, the ovine trophoblast cell line (AH-1) and in response to the TLR-4 ligand LPS, the abortifacient organism Waddlia chondrophila and 1α,25-dihydroxyvitamin D3. Using RT-PCR, expression of the CHDP SMAP-29, sBD-1 and sBD-2 was assessed in the AH-1 cell line in response to LPS, 1α,25-dihydroxyvitamin D3 exposure (a known stimulator of cathelicidin gene expression), or W. chondrophila infection. Expression of cathelicidin in the trophoblast compartment of the ovine placenta and in the ovine trophoblast cell line (AH-1) was also established. AH-1 cells did not upregulate expression of CHDP in response to LPS, but sBD-1 and sBD-2 expression was significantly increased in response to W. chondrophila infection. SMAP-29 expression was not altered by in vitro exposure to 1α,25-dihydroxyvitamin D3. This study demonstrates that the ovine trophoblast expresses cathelicidins, but does not upregulate expression of CHDP in response to LPS. Ovine trophoblasts are shown to differentially regulate expression of CHDP and lack a demonstrable vitamin D-mediated cathelicidin response. PMID:27348190

  13. Plant Community Diversity Influences Allocation to Direct Chemical Defence in Plantago lanceolata

    PubMed Central

    Mraja, Anne; Unsicker, Sybille B.; Reichelt, Michael; Gershenzon, Jonathan; Roscher, Christiane

    2011-01-01

    Background Forecasting the consequences of accelerating rates of changes in biodiversity for ecosystem functioning requires a mechanistic understanding of the relationships between the structure of biological communities and variation in plant functional characteristics. So far, experimental data of how plant species diversity influences the investment of individual plants in direct chemical defences against herbivores and pathogens is lacking. Methodology/Principal Findings We used Plantago lanceolata as a model species in experimental grasslands differing in species richness and composition (Jena Experiment) to investigate foliar concentrations of the iridoid glycosides (IG), catalpol and its biosynthetic precursor aucubin. Total IG and aucubin concentrations decreased, while catalpol concentrations increased with increasing plant diversity in terms of species or functional group richness. Negative plant diversity effects on total IG and aucubin concentrations correlated with increasing specific leaf area of P. lanceolata, suggesting that greater allocation to light acquisition reduced the investment into these carbon-based defence components. In contrast, increasing leaf nitrogen concentrations best explained increasing concentrations of the biosynthetically more advanced IG, catalpol. Observed levels of leaf damage explained a significant proportion of variation in total IG and aucubin concentrations, but did not account for variance in catalpol concentrations. Conclusions/Significance Our results clearly show that plants growing in communities of varying species richness and composition differ in their defensive chemistry, which may modulate plant susceptibility to enemy attack and consequently their interactions with higher trophic level organisms. PMID:22174766

  14. Convergent evolution in biosynthesis of cyanogenic defence compounds in plants and insects.

    PubMed

    Jensen, Niels Bjerg; Zagrobelny, Mika; Hjernø, Karin; Olsen, Carl Erik; Houghton-Larsen, Jens; Borch, Jonas; Møller, Birger Lindberg; Bak, Søren

    2011-01-01

    For more than 420 million years, plants, insects and their predators have co-evolved based on a chemical arms race including deployment of refined chemical defence systems by each player. Cyanogenic glucosides are produced by numerous plants and by some specialized insects and serve an important role as defence compounds in these intimate interactions. Burnet moth larvae are able to sequester cyanogenic glucosides from their food plant as well as to carry out de novo biosynthesis. Here we show that three genes (CYP405A2, CYP332A3 and UGT33A1) encode the entire biosynthetic pathway of cyanogenic glucosides in the Burnet moth Zygaena filipendulae. In both plants and insects, convergent evolution has led to two multifunctional P450 enzymes each catalysing unusual reactions and a glucosyl-transferase acting in sequence to catalyse cyanogenic glucoside formation. Thus, plants and insects have independently found a way to package a cyanide time bomb to fend off herbivores and predators. PMID:21505429

  15. The extremophile Nicotiana benthamiana has traded viral defence for early vigour.

    PubMed

    Bally, Julia; Nakasugi, Kenlee; Jia, Fangzhi; Jung, Hyungtaek; Ho, Simon Y W; Wong, Mei; Paul, Chloe M; Naim, Fatima; Wood, Craig C; Crowhurst, Ross N; Hellens, Roger P; Dale, James L; Waterhouse, Peter M

    2015-01-01

    A single lineage of Nicotiana benthamiana is widely used as a model plant(1) and has been instrumental in making revolutionary discoveries about RNA interference (RNAi), viral defence and vaccine production. It is peerless in its susceptibility to viruses and its amenability in transiently expressing transgenes(2,3). These unparalleled characteristics have been associated both positively and negatively with a disruptive insertion in the RNA-dependent RNA polymerase 1 gene, Rdr1(4-6). For a plant so routinely used in research, the origin, diversity and evolution of the species, and the basis of its unusual abilities, have been relatively unexplored. Here, by comparison with wild accessions from across the spectrum of the species' natural distribution, we show that the laboratory strain of N. benthamiana is an extremophile originating from a population that has retained a mutation in Rdr1 for ∼0.8 Myr and thereby traded its defence capacity for early vigour and survival in the extreme habitat of central Australia. Reconstituting Rdr1 activity in this isolate provided protection. Silencing the functional allele in a wild strain rendered it hypersusceptible and was associated with a doubling of seed size and enhanced early growth rate. These findings open the way to a deeper understanding of the delicate balance between protection and vigour. PMID:27251536

  16. Plasma membrane order and fluidity are diversely triggered by elicitors of plant defence

    PubMed Central

    Sandor, Roman; Der, Christophe; Grosjean, Kevin; Anca, Iulia; Noirot, Elodie; Leborgne-Castel, Nathalie; Lochman, Jan; Simon-Plas, Françoise; Gerbeau-Pissot, Patricia

    2016-01-01

    Although plants are exposed to a great number of pathogens, they usually defend themselves by triggering mechanisms able to limit disease development. Alongside signalling events common to most such incompatible interactions, modifications of plasma membrane (PM) physical properties could be new players in the cell transduction cascade. Different pairs of elicitors (cryptogein, oligogalacturonides, and flagellin) and plant cells (tobacco and Arabidopsis) were used to address the issue of possible modifications of plant PM biophysical properties induced by elicitors and their links to other events of the defence signalling cascade. We observed an increase of PM order whatever the elicitor/plant cell pair used, provided that a signalling cascade was induced. Such membrane modification is dependent on the NADPH oxidase-mediated reactive oxygen species production. Moreover, cryptogein, which is the sole elicitor able to trap sterols, is also the only one able to trigger an increase in PM fluidity. The use of cryptogein variants with altered sterol-binding properties confirms the strong correlation between sterol removal from the PM and PM fluidity enhancement. These results propose PM dynamics as a player in early signalling processes triggered by elicitors of plant defence. PMID:27604805

  17. Are there lessons to be learned from a more scientific approach to mental condition defences?

    PubMed

    Claydon, Lisa

    2012-01-01

    The timing of the English Law Commission's consideration of reform to the law of insanity coincides with increasing scientific and in particular neuroscientific understanding of the brain. The work of researchers is leading to a greater comprehension of what had been termed irresistible impulses to commit crime and of the impact of brain damage, particularly evidence of brain lesions and frontal lobe damage on behaviour. There remain problems in establishing causal relationships which might diminish or eliminate criminal responsibility for crimes committed by those suffering from pre existing mental conditions at the time they commit a criminal offence. This is especially the case where those mental conditions are of short duration. However, the law should not ignore the best available scientific knowledge. Neuroscientific advances are already informing court deliberations in England and Wales: assisting in considerations of guilt, fitness to plead and in sentencing. In terms of the insanity defence the questions that the law seeks to address are not necessarily the most medically or scientifically pertinent questions. They remain grounded in 19th century scientific understanding. It is argued that the more nuanced Dutch approach to mental condition defences warrants very serious consideration by those charged with making proposals to reform the English law.

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

    PubMed

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

    2016-07-21

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

  19. Differential shell strength of Cepaea nemoralis colour morphs—implications for their anti-predator defence

    NASA Astrophysics Data System (ADS)

    Rosin, Zuzanna M.; Kobak, Jarosław; Lesicki, Andrzej; Tryjanowski, Piotr

    2013-09-01

    One of the most spectacular evolutionary forces is predation, evidenced to stimulate polymorphism in many prey species. Shell colour polymorphism of the land snail Cepaea nemoralis is a well-known model in evolutionary research. Nevertheless, the knowledge on the ecological causes driving its evolution remains incomplete and proximal factors shaping predatory pressure on C. nemoralis morphs are unknown. We evaluated shell crushing resistance and thickness, constituting crucial snail anti-predator defences in two shell areas (the apex and labium) of eight C. nemoralis morphotypes differing in shell colour and banding pattern. A GLM showed a significant effect of shell colour, banding pattern and shell thickness on shell strength. Pink shells were stronger than yellow ones, and banded forms had stronger shells than unbanded snails. The labium (usually attacked by mice) was generally thicker and more resistant than the apex (usually crushed by birds). Thicker shells were more resistant to crushing, and the rate of shell strength increase per unit of shell thickness was greater in pink and banded individuals compared to yellow and unbanded ones. Yellow and unbanded morphs have been found to be preferred by mice in the previous studies, which suggests that shell strength may be an important trait used in prey selection by these shell-crushing predators. The differences in potential anti-predator defences among snail morphs, found in the present study, justify future research on direct effect of C. nemoralis morphs shell strength on predator selectivity.

  20. Individual contributions to territory defence in a cooperative breeder: weighing up the benefits and costs.

    PubMed

    Mares, Rafael; Young, Andrew J; Clutton-Brock, Tim H

    2012-10-01

    While investment in territory defence is expected to be influenced by its benefits, the additional role that costs may play is rarely considered. Here, we quantify both benefits and costs of repelling prospecting males in cooperative meerkats, and demonstrate that both are required to explain the substantial variation in individual contributions to the defence observed. Males benefit more from repelling prospectors than females, as males may lose dominance and be expelled during intrusions. Accordingly, males invest the most in repelling prospectors. We also show that males experience an associated cost in the form of reduced weight gain and, as such, heavier males contribute more to chasing prospectors. Finally, we show evidence of a cost not restricted to individuals engaged in chasing: both males and females reduce their contributions to feeding dependent pups when prospectors are present, resulting in a reduction in pup weight gain in this context. Males appear to adjust their contributions to chasing in light of this cost, chasing at lower rates when their group contains dependent young. Our findings support the view that investment in cooperative behaviours can be attributed to benefits and costs, and highlight the additional importance of considering trade-offs in investment between cooperative behaviours.

  1. Chloroplasts play a central role in plant defence and are targeted by pathogen effectors.

    PubMed

    de Torres Zabala, Marta; Littlejohn, George; Jayaraman, Siddharth; Studholme, David; Bailey, Trevor; Lawson, Tracy; Tillich, Michael; Licht, Dirk; Bölter, Bettina; Delfino, Laura; Truman, William; Mansfield, John; Smirnoff, Nicholas; Grant, Murray

    2015-01-01

    Microbe associated molecular pattern (MAMP) receptors in plants recognize MAMPs and activate basal defences; however a complete understanding of the molecular and physiological mechanisms conferring immunity remains elusive. Pathogens suppress active defence in plants through the combined action of effector proteins. Here we show that the chloroplast is a key component of early immune responses. MAMP perception triggers the rapid, large-scale suppression of nuclear encoded chloroplast-targeted genes (NECGs). Virulent Pseudomonas syringae effectors reprogramme NECG expression in Arabidopsis, target the chloroplast and inhibit photosynthetic CO2 assimilation through disruption of photosystem II. This activity prevents a chloroplastic reactive oxygen burst. These physiological changes precede bacterial multiplication and coincide with pathogen-induced abscisic acid (ABA) accumulation. MAMP pretreatment protects chloroplasts from effector manipulation, whereas application of ABA or the inhibitor of photosynthetic electron transport, DCMU, abolishes the MAMP-induced chloroplastic reactive oxygen burst, and enhances growth of a P. syringae hrpA mutant that fails to secrete effectors. PMID:27250009

  2. Histology and cell wall biochemistry of stone cells in the physical defence of conifers against insects.

    PubMed

    Whitehill, Justin G A; Henderson, Hannah; Schuetz, Mathias; Skyba, Oleksandr; Yuen, Macaire Man Saint; King, John; Samuels, A Lacey; Mansfield, Shawn D; Bohlmann, Jörg

    2016-08-01

    Conifers possess an array of physical and chemical defences against stem-boring insects. Stone cells provide a physical defence associated with resistance against bark beetles and weevils. In Sitka spruce (Picea sitchensis), abundance of stone cells in the cortex of apical shoots is positively correlated with resistance to white pine weevil (Pissodes strobi). We identified histological, biochemical and molecular differences in the stone cell phenotype of weevil resistant (R) or susceptible (S) Sitka spruce genotypes. R trees displayed significantly higher quantities of cortical stone cells near the apical shoot node, the primary site for weevil feeding. Lignin, cellulose, xylan and mannan were the most abundant components of stone cell secondary walls, respectively. Lignin composition of stone cells isolated from R trees contained a higher percentage of G-lignin compared with S trees. Transcript profiling revealed higher transcript abundance in the R genotype of coumarate 3-hydroxylase, a key monolignol biosynthetic gene. Developing stone cells in current year apical shoots incorporated fluorescent-tagged monolignol into the secondary cell wall, while mature stone cells of previous year apical shoots did not. Stone cell development is an ephemeral process, and fortification of shoot tips in R trees is an effective strategy against insect feeding.

  3. Antioxidant defence in UV-irradiated tobacco leaves is centred on hydrogen-peroxide neutralization.

    PubMed

    Majer, Petra; Czégény, Gyula; Sándor, Györgyi; Dix, Philip J; Hideg, Eva

    2014-09-01

    Greenhouse grown tobacco (Nicotiana tabacum L. cv. Petit Havana) plants were exposed to supplemental UV centred at 318 nm and corresponding to 13.6 kJ m(-2) d(-1) biologically effective UV-B (280-315 nm) radiation. After 6 days this treatment decreased photosynthesis by 30%. Leaves responded by a large increase in UV-absorbing pigment content and antioxidant capacities. UV-stimulated defence against ROS was strongest in chloroplasts, since activities of plastid enzymes FeSOD and APX had larger relative increases than other, non-plastid specific SODs or peroxidases. In addition, non-enzymatic defence against hydroxyl radicals was doubled in UV treated leaves as compared to controls. In UV treated leaves, the extent of activation of ROS neutralizing capacities followed a peroxidases > hydroxyl-radical neutralization > SOD order. These results suggest that highly effective hydrogen peroxide neutralization is the focal point of surviving UV-inducible oxidative stress and argue against a direct signalling role of hydrogen peroxide in maintaining adaptation to UV, at least in laboratory experiments.

  4. Plasma membrane order and fluidity are diversely triggered by elicitors of plant defence.

    PubMed

    Sandor, Roman; Der, Christophe; Grosjean, Kevin; Anca, Iulia; Noirot, Elodie; Leborgne-Castel, Nathalie; Lochman, Jan; Simon-Plas, Françoise; Gerbeau-Pissot, Patricia

    2016-09-01

    Although plants are exposed to a great number of pathogens, they usually defend themselves by triggering mechanisms able to limit disease development. Alongside signalling events common to most such incompatible interactions, modifications of plasma membrane (PM) physical properties could be new players in the cell transduction cascade. Different pairs of elicitors (cryptogein, oligogalacturonides, and flagellin) and plant cells (tobacco and Arabidopsis) were used to address the issue of possible modifications of plant PM biophysical properties induced by elicitors and their links to other events of the defence signalling cascade. We observed an increase of PM order whatever the elicitor/plant cell pair used, provided that a signalling cascade was induced. Such membrane modification is dependent on the NADPH oxidase-mediated reactive oxygen species production. Moreover, cryptogein, which is the sole elicitor able to trap sterols, is also the only one able to trigger an increase in PM fluidity. The use of cryptogein variants with altered sterol-binding properties confirms the strong correlation between sterol removal from the PM and PM fluidity enhancement. These results propose PM dynamics as a player in early signalling processes triggered by elicitors of plant defence. PMID:27604805

  5. Defence sugarcane glycoproteins disorganize microtubules and prevent nuclear polarization and germination of Sporisorium scitamineum teliospores.

    PubMed

    Sánchez-Elordi, Elena; Baluška, František; Echevarría, Clara; Vicente, Carlos; Legaz, M Estrella

    2016-08-01

    Microtubules (MTs) are involved in the germination of Sporisorium scitamineum teliospores. Resistant varieties of sugar cane plants produce defence glycoproteins that prevent the infection of the plants by the filamentous fungi Sporisorium scitamineum. Here, we show that a fraction of these glycoproteins prevents the correct arrangement of MTs and causes nuclear fragmentation defects. As a result, nuclei cannot correctly migrate through the growing hyphae, causing germinative failure. Arginase activity contained in defence glycoproteins is already described for preventing fungal germination. Now, its enzymatically active form is presented as a link between the defensive capacity of glycoproteins and the MT disorganization in fungal cells. Active arginase is produced in healthy and resistant plants; conversely, it is not detected in the juice from susceptible varieties, which explains why MT depolarization, nuclear disorganization as well as germination of teliospores are not significantly affected by glycoproteins from non-resistant plants. Our results also suggest that susceptible plants try to increase their levels of arginase after detecting the presence of the pathogen. However, this signal comes "too late" and such defensive mechanism fails. PMID:27372179

  6. Defence behaviours of the praying mantis Tenodera aridifolia in response to looming objects.

    PubMed

    Yamawaki, Yoshifumi

    2011-11-01

    Defence responses to approaching objects were observed in the mantis Tenodera aridifolia. The mantis showed three kinds of behaviour, fixation, evasion and cryptic reaction. The cryptic reaction consisted of rapid retraction of the forelegs under the prothorax or rapid extending of the forelegs in the forward direction. Obstructing the mantis' sight decreased its response rates, suggesting that the visual stimuli generated by an approaching object elicited the cryptic reaction. The response rate of the cryptic reactions was highest for objects that approached on a direct collision course. Deviation in a horizontal direction from the direct collision course resulted in a reduced response. The response rate of the cryptic reaction increased as the approaching velocity of the object increased, and the rate decreased as the object ceased its approach at a greater distance from the mantis. These results suggest that the function of the observed cryptic reactions is defence against impending collisions. The possible role of the looming-sensitive neuron in the cryptic reaction is also discussed. PMID:21851823

  7. Prioritizing plant defence over growth through WRKY regulation facilitates infestation by non-target herbivores.

    PubMed

    Li, Ran; Zhang, Jin; Li, Jiancai; Zhou, Guoxin; Wang, Qi; Bian, Wenbo; Erb, Matthias; Lou, Yonggen

    2015-06-17

    Plants generally respond to herbivore attack by increasing resistance and decreasing growth. This prioritization is achieved through the regulation of phytohormonal signaling networks. However, it remains unknown how this prioritization affects resistance against non-target herbivores. In this study, we identify WRKY70 as a specific herbivore-induced, mitogen-activated protein kinase-regulated rice transcription factor that physically interacts with W-box motives and prioritizes defence over growth by positively regulating jasmonic acid (JA) and negatively regulating gibberellin (GA) biosynthesis upon attack by the chewing herbivore Chilo suppressalis. WRKY70-dependent JA biosynthesis is required for proteinase inhibitor activation and resistance against C. suppressalis. In contrast, WRKY70 induction increases plant susceptibility against the rice brown planthopper Nilaparvata lugens. Experiments with GA-deficient rice lines identify WRKY70-dependent GA signaling as the causal factor in N. lugens susceptibility. Our study shows that prioritizing defence over growth leads to a significant resistance trade-off with important implications for the evolution and agricultural exploitation of plant immunity.

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

    PubMed Central

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

    2015-01-01

    Numerous studies have highlighted the key roles of oxidative stress and inflammation in aging-related diseases such as obesity, type 2 diabetes, age-related macular degeneration (AMD), and Alzheimer's disease (AD). In aging cells, the natural antioxidant capacity decreases and the overall efficiency of reparative systems against cell damage becomes impaired. There is convincing data that stilbene compounds, a diverse group of natural defence phenolics, abundant in grapes, berries, and conifer bark waste, may confer a protective effect against aging-related diseases. This review highlights recent data helping to clarify the molecular mechanisms involved in the stilbene-mediated protection against oxidative stress. The impact of stilbenes on the nuclear factor-erythroid-2-related factor-2 (Nrf2) mediated cellular defence against oxidative stress as well as the potential roles of SQSTM1/p62 protein in Nrf2/Keap1 signaling and autophagy will be summarized. The therapeutic potential of stilbene compounds against the most common aging-related diseases is discussed. PMID:26180583

  9. Introduced Predator Elicits Deficient Brood Defence Behaviour in a Crater Lake Fish

    PubMed Central

    Lehtonen, Topi K.; McCrary, Jeffrey K.; Meyer, Axel

    2012-01-01

    Introduced species represent one of the most serious global threats to biodiversity. In this field-based study, we assessed behavioural responses of brood tending cichlid fish to an invasive predator of their offspring. This was achieved by comparing parental defence responses of the endangered arrow cichlid (Amphilophus zaliosus), a fish species endemic to the crater lake Apoyo in Nicaragua, towards the bigmouth sleeper (Gobiomorus dormitor), a formidable predator of cichlid fry, and all other potential fish predators of offspring. The bigmouth sleeper was recently introduced into Apoyo but naturally co-exists with cichlids in a few other Nicaraguan lakes. Arrow cichlid parents allowed bigmouth sleepers to advance much closer to their fry than other predators before initiating aggressive brood defence behaviours. Interestingly, parents of a very closely related species, A. sagittae, which has coevolved with bigmouth sleepers in crater lake Xiloá, reacted to approaching bigmouth sleepers at comparable distances as to other predators of cichlid fry. These results provide a novel demonstration of the specific mechanism (i.e. naive parental behaviour) by which invasive predators may negatively affect species that lack the adequate behavioural repertoire. PMID:22253881

  10. Individual contributions to territory defence in a cooperative breeder: weighing up the benefits and costs.

    PubMed

    Mares, Rafael; Young, Andrew J; Clutton-Brock, Tim H

    2012-10-01

    While investment in territory defence is expected to be influenced by its benefits, the additional role that costs may play is rarely considered. Here, we quantify both benefits and costs of repelling prospecting males in cooperative meerkats, and demonstrate that both are required to explain the substantial variation in individual contributions to the defence observed. Males benefit more from repelling prospectors than females, as males may lose dominance and be expelled during intrusions. Accordingly, males invest the most in repelling prospectors. We also show that males experience an associated cost in the form of reduced weight gain and, as such, heavier males contribute more to chasing prospectors. Finally, we show evidence of a cost not restricted to individuals engaged in chasing: both males and females reduce their contributions to feeding dependent pups when prospectors are present, resulting in a reduction in pup weight gain in this context. Males appear to adjust their contributions to chasing in light of this cost, chasing at lower rates when their group contains dependent young. Our findings support the view that investment in cooperative behaviours can be attributed to benefits and costs, and highlight the additional importance of considering trade-offs in investment between cooperative behaviours. PMID:22810429

  11. Variation in defence strategies in two species of the genus Beilschmiedia under differing soil nutrient and rainfall conditions.

    PubMed

    Simon, J; Miller, R E; Woodrow, I E

    2007-01-01

    The relationships between various leaf functional traits that are important in plant growth (e.g., specific leaf area) have been investigated in recent studies; however, research in this context on plants that are highly protected by chemical defences, particularly resource-demanding nitrogen-based defence, is lacking. We collected leaves from cyanogenic (N-defended) Beilschmiedia collina B. Hyland and acyanogenic (C-defended) Beilschmiedia tooram (F. M. Bailey) B. Hyland at high- and low-soil nutrient sites in two consecutive years that varied significantly in rainfall. We then measured the relationships between chemical defence and morphological and functional leaf traits under the different environmental conditions. We found that the two species differed significantly in their resource allocation to defence as well as leaf morphology and function. The N defended species had a higher leaf nitrogen concentration, whereas the C-defended species had higher amounts of C-based chemical defences (i.e., total phenolics and condensed tannins). The C-defended species also tended to have higher force to fracture and increased leaf toughness. In B. collina, cyanogenic glycoside concentration was higher with higher rainfall, but not with higher soil nutrients. Total phenolic concentration was higher at the high soil nutrient site in B. tooram, but lower in B. collina; however, with higher rainfall an increase was found in B. tooram, while phenolics decreased in B. collina. Condensed tannin concentration decreased in both species with rainfall and nutrient availability. We conclude that chemical defence is correlated with leaf functional traits and that variation in environmental resources affects this correlation.

  12. Integrated defence reaction elicited by excitatory amino acid microinjection in the midbrain periaqueductal grey region of the unrestrained cat.

    PubMed

    Bandler, R; Carrive, P

    1988-01-26

    Unilateral microinjections (0.20 microliter) of the excitatory amino acids (EAA), L-aspartate (ASP), D,L-homocysteate (DLH) or kainate (KA) were made into the midbrain of freely moving cats. Injections of DLH (20 nmol) or ASP (200 nmol) made within the midbrain periaqueductal grey matter (PAG) consistently elicited a threat display characteristic of defensive behaviour (i.e., pupillary dilatation, piloerection, retraction of the ears, sideways backing, arching of the back, hissing, howling, growling), whereas injections of DLH or ASP made in the tegmentum bordering the PAG did not elicit such behaviour. Injections of KA (940 pmol) made within the PAG, but not the tegmentum, elicited not only a threat display but also directed attack (striking with unsheathed claws and biting). As injections of EAA depolarize cell bodies, but not axons, the results suggest that a population of neurones whose excitation elicits all of the behavioural signs of defence, including directed attack, is found within the PAG. Histology indicated that the region of the PAG from which the defence reaction was elicited was not confined to any PAG subnucleus. Rather, the 'defence region' of the PAG formed a cylindrical column lateral to the midbrain aqueduct, approximately 1.5 mm in diameter and 5.0 mm in length, the rostral end of which lay dorsal to the caudal end. Further, it was found that EAA microinjections made in different portions of the defence region of the PAG elicited defence reactions characterised by different patterns of vocalization and differing intensities of display. It was also observed following unilateral injection of KA into the PAG that defence reactions, including attack, were elicited by approach in the visual hemifield or touch of the body contralateral, but not ipsilateral, to the injection site. The asymmetry of the defence reaction was not due to any obvious ipsilateral motor impairment and thus suggests that the PAG mediation of the defence reaction, in addition

  13. Investigations of phagocytosis concerning the immunological defence mechanism of Mytilus edulis using a sublethal luminescent bacterial assay (Photobacterium phosphoreum).

    PubMed

    Hansen, P D; Bock, R; Brauer, F

    1991-01-01

    1. A simple method for the determination of phagocytosis activity using mussel hemocytes by measuring the bioluminescence is presented. 2. The immunological defence activity based on phagocytosis is measured and quantified by a luminescent bacterial assay with Photobacterium phosphoreum. 3. The measuring system allows us to establish the stress of the immunological defence mechanism of organisms exposed to chemicals and polluted rivers or sewage. Results with reference substances and the phagocytosis indices of exposed mussels from Norwegian aquaculture plants compared to those of mussels from the German Wadden Sea are given as examples.

  14. 50 kW laser weapon demonstrator of Rheinmetall Waffe munition

    NASA Astrophysics Data System (ADS)

    Ludewigt, K.; Riesbeck, Th.; Graf, A.; Jung, M.

    2013-10-01

    We will present the setup of a 50 kW Laser Weapon Demonstrator (LWD) and results achieved with this system. The LWD is a ground based Air Defence system consisting of a Skyguard sensor unit for target acquisition and two laser equipped weapon turrets. The weapon turrets used are standard air defence turrets of Rheinmetall Air Defence which were equipped with several 10 kW Laser Weapon Modules (LWM). Each LWM consists of one 10 kW fiber laser and a beam forming unit (BFU). Commercial of the shelf fiber laser were modified for our defence applications. The BFU providing diffraction limited beam focusing, target imaging and fine tracking of the target was developed. The LWD was tested in a firing campaign at Rheinmetall test ground in Switzerland. All laser beams of both weapon turrets were superimposed on stationary and dynamic targets. Test results of the LWD for the scenarios Air Defence and C-RAMM (counter rockets, artillery, mortar and missiles) will be presented. An outlook for the next development stage towards a 100 kW class laser weapon on RWM will be given.

  15. The mirror has two faces: dissociative identity disorder and the defence of pathological criminal incapacity--a South African criminal law perspective.

    PubMed

    Stevens, Philip

    2013-03-01

    Dissociative identity disorder poses numerous medico legal issues whenever the insanity defence emerges. Within the context of the South African criminal law, the impact of dissociative identity disorder on criminal responsibility has only been addressed very briefly in one decided case. Various questions arise as to the impact that the distinctive diagnostic features of dissociative identity disorder could possibly have on the defence of pathological criminal incapacity, or better known as the insanity defence, within the ambit of the South African criminal law. In this contribution the author reflects on the mental disorder known as dissociative identity disorder or multiple personality disorder, against the backdrop of the defence of pathological criminal incapacity. Reflections are also provided pertaining to the various medico legal issues at stake whenever this defence has to be adjudicated upon. PMID:23781763

  16. The mirror has two faces: dissociative identity disorder and the defence of pathological criminal incapacity--a South African criminal law perspective.

    PubMed

    Stevens, Philip

    2013-03-01

    Dissociative identity disorder poses numerous medico legal issues whenever the insanity defence emerges. Within the context of the South African criminal law, the impact of dissociative identity disorder on criminal responsibility has only been addressed very briefly in one decided case. Various questions arise as to the impact that the distinctive diagnostic features of dissociative identity disorder could possibly have on the defence of pathological criminal incapacity, or better known as the insanity defence, within the ambit of the South African criminal law. In this contribution the author reflects on the mental disorder known as dissociative identity disorder or multiple personality disorder, against the backdrop of the defence of pathological criminal incapacity. Reflections are also provided pertaining to the various medico legal issues at stake whenever this defence has to be adjudicated upon.

  17. A Golden Age of Security and Education? Adult Education for Civil Defence in the United States 1950-1970

    ERIC Educational Resources Information Center

    Preston, John

    2015-01-01

    A number of authors consider that the early period of US security and education (1950-1970) was in some way a "golden age" where there was a prevailing societal orientation towards civil defence. This is supported, to some extent, through "Duck and Cover" type activities in schools and in community preparedness efforts. This…

  18. Tomato yellow leaf curl virus differentially influences plant defence responses to a vector and a non-vector herbivore.

    PubMed

    Su, Qi; Mescher, Mark C; Wang, Shaoli; Chen, Gong; Xie, Wen; Wu, Qingjun; Wang, Wenkai; Zhang, Youjun

    2016-03-01

    Plants frequently engage in simultaneous interactions with diverse classes of biotic antagonists. Differential induction of plant defence pathways by these antagonists, and interactions between pathways, can have important ecological implications; however, these effects are currently not well understood. We explored how Tomato yellow leaf curl virus (TYLCV) influenced the performance of its vector (Bemisia tabaci) and a non-vector herbivore (Tetranychus urticae) occurring separately or together on tomato plants (Solanum lycopersicum). TYLCV enhanced the performance of B. tabaci, although this effect was statistically significant only in the absence of T. urticae, which adversely affected B. tabaci performance regardless of infection status. In contrast, the performance of T. urticae was enhanced (only) by the combined presence of TYLCV and B. tabaci. Analyses of phytohormone levels and defence gene expression in wild-type tomatoes and various plant-defence mutants indicate that the enhancement of herbivore performance (for each species) entails the disruption of downstream defences in the jasmonic acid (JA) pathway. For T. urticae, this disruption appears to involve antagonistic effects of salicylic acid (SA), which is cumulatively induced to high levels by B. tabaci and TYLCV. In contrast, TYLCV was found to suppress JA-mediated responses to B. tabaci via mechanisms independent of SA. PMID:26436779

  19. Phytochrome B-mediated activation of lipoxygenase modulates an excess red light-induced defence response in Arabidopsis

    PubMed Central

    Zhao, Yuanyuan; Zhou, Jun; Xing, Da

    2014-01-01

    Lipoxygenase (LOX), a non-haem-iron-containing dioxygenase, is activated under various biotic or abiotic stresses to trigger a series resistance response, but the molecular mechanism of LOX activation remains unclear. This work investigated the activation of LOX during the plant defence response induced by excess red light (RL). In conditions of RL-induced defence, Arabidopsis LOX activity and transcription levels of LOX2, LOX3, and LOX4 were both upregulated. Under RL, phytochrome B promoted the degradation of phytochrome-interacting factor 3 (PIF3), a factor that inhibited the expression levels of LOXs, and thus the transcription levels of LOX2, LOX3, and LOX4 were increased. Upon pathogen infection, the activity of mitogen-activated protein kinase 3 (MPK3) and MPK6 was increased in plants pre-treated with RL. Moreover, experiments with the inhibitor PD98059 and mutants mpk3 and mpk6-2 demonstrated that MPK3 and MPK6 were both responsible for LOX activation. Further results showed that, in response to RL, an increase in cytoplasmic calcium concentration and upregulation of calmodulin 3 (CaM3) transcript level occurred upstream of MPK3 and MPK6 activation. Collectively, these results suggested that activation of LOX both at the transcript level and in terms of activity modulates the defence response induced by RL, providing a new insight into the mechanistic study of LOX during plant defences. PMID:24916071

  20. Knowing your friends and foes--plant receptor-like kinases as initiators of symbiosis or defence.

    PubMed

    Antolín-Llovera, Meritxell; Petutsching, Elena Kristin; Ried, Martina Katharina; Lipka, Volker; Nürnberger, Thorsten; Robatzek, Silke; Parniske, Martin

    2014-12-01

    The decision between defence and symbiosis signalling in plants involves alternative and modular plasma membrane-localized receptor complexes. A critical step in their activation is ligand-induced homo- or hetero-oligomerization of leucine-rich repeat (LRR)- and/or lysin motif (LysM) receptor-like kinases (RLKs). In defence signalling, receptor complexes form upon binding of pathogen-associated molecular patterns (PAMPs), including the bacterial flagellin-derived peptide flg22, or chitin. Similar mechanisms are likely to operate during the perception of microbial symbiont-derived (lipo)-chitooligosaccharides. The structurally related chitin-oligomer ligands chitooctaose and chitotetraose trigger defence and symbiosis signalling, respectively, and their discrimination involves closely related, if not identical, LysM-RLKs. This illustrates the demand for and the challenges imposed on decision mechanisms that ensure appropriate signal initiation. Appropriate signalling critically depends on abundance and localization of RLKs at the cell surface. This is regulated by internalization, which also provides a mechanism for the removal of activated signalling RLKs. Abundance of the malectin-like domain (MLD)-LRR-RLK Symbiosis Receptor-like Kinase (SYMRK) is additionally controlled by cleavage of its modular ectodomain, which generates a truncated and rapidly degraded RLK fragment. This review explores LRR- and LysM-mediated signalling, the involvement of MLD-LRR-RLKs in symbiosis and defence, and the role of endocytosis in RLK function.

  1. A switch from constitutive chemical defence to inducible innate immune responses in the invasive ladybird Harmonia axyridis.

    PubMed

    Schmidtberg, Henrike; Röhrich, Christian; Vogel, Heiko; Vilcinskas, Andreas

    2013-06-23

    The harlequin ladybird, Harmonia axyridis, has emerged as a model species for invasion biology, reflecting its remarkable capacity to outcompete native ladybird species when introduced into new habitats. This ability may be associated with its prominent resistance to pathogens and intraguild predation. We recently showed that the constitutive antibacterial activity present in the haemolymph of H. axyridis beetles can be attributed to the chemical defence compound harmonine. Here, we demonstrate that H. axyridis differs from other insects, including the native ladybird Coccinella septempunctata, by reducing rather than increasing the antimicrobial activity of its haemolymph following the injection of bacteria. However, both species produce new or more abundant proteins in the haemolymph, indicating that bacterial challenge induces innate immune responses associated with the synthesis of immunity-related proteins. Our results suggest that H. axyridis beetles can switch from constitutive chemical defence to inducible innate immune responses, supporting hypothesis that inducible antimicrobial peptides protect host beetles against pathogens that survive constitutive defences. These alternative antimicrobial defence mechanisms may reflect a trade-off resulting from fitness-related costs associated with the simultaneous synthesis of harmonine and antimicrobial peptides/proteins. PMID:23466480

  2. A switch from constitutive chemical defence to inducible innate immune responses in the invasive ladybird Harmonia axyridis.

    PubMed

    Schmidtberg, Henrike; Röhrich, Christian; Vogel, Heiko; Vilcinskas, Andreas

    2013-06-23

    The harlequin ladybird, Harmonia axyridis, has emerged as a model species for invasion biology, reflecting its remarkable capacity to outcompete native ladybird species when introduced into new habitats. This ability may be associated with its prominent resistance to pathogens and intraguild predation. We recently showed that the constitutive antibacterial activity present in the haemolymph of H. axyridis beetles can be attributed to the chemical defence compound harmonine. Here, we demonstrate that H. axyridis differs from other insects, including the native ladybird Coccinella septempunctata, by reducing rather than increasing the antimicrobial activity of its haemolymph following the injection of bacteria. However, both species produce new or more abundant proteins in the haemolymph, indicating that bacterial challenge induces innate immune responses associated with the synthesis of immunity-related proteins. Our results suggest that H. axyridis beetles can switch from constitutive chemical defence to inducible innate immune responses, supporting hypothesis that inducible antimicrobial peptides protect host beetles against pathogens that survive constitutive defences. These alternative antimicrobial defence mechanisms may reflect a trade-off resulting from fitness-related costs associated with the simultaneous synthesis of harmonine and antimicrobial peptides/proteins.

  3. Impact of transgenerational immune priming on the defence of insect eggs against parasitism.

    PubMed

    Trauer-Kizilelma, Ute; Hilker, Monika

    2015-07-01

    Insects are known to prime the immune state of their offspring. However, although the beginning of insect life, the egg stage, is often greatly endangered by parasitism, no knowledge is available regarding whether transgenerational immune priming improves the immune responses of insect eggs to actual parasitoid attacks. Our study revealed suppression of the development of parasitoids in transgenerationally immune-primed Manduca sexta eggs and reduced emergence rates of parasitoids from these eggs. The higher defence efficiency of immune-primed M. sexta eggs against parasitoids was in agreement with the increased antibacterial activity and phenoloxidase activity of these eggs in response to parasitism compared to the eggs of control parents. Our study showed that immunochallenged insect parents could enable their offspring already in the egg stage to defend more efficiently against parasitic invaders. We discuss whether M. sexta benefits from transgenerational immune priming of eggs by limiting the population growth of egg parasitoids. PMID:25790896

  4. How to take particle physics seriously: A further defence of axiomatic quantum field theory

    NASA Astrophysics Data System (ADS)

    Fraser, Doreen

    Further arguments are offered in defence of the position that the variant of quantum field theory (QFT) that should be subject to interpretation and foundational analysis is axiomatic quantum field theory. I argue that the successful application of renormalization group (RG) methods within alternative formulations of QFT illuminates the empirical content of QFT, but not the theoretical content. RG methods corroborate the point of view that QFT is a case of the underdetermination of theory by empirical evidence. I also urge caution in extrapolating interpretive conclusions about QFT from the application of RG methods in other contexts (e.g., condensed matter physics). This paper replies to criticisms advanced by David Wallace, but aims to be self-contained.

  5. [The Central Military Hospital of the People's Commissariat for Defence during the Great Patriotic War].

    PubMed

    Simonenko, V B; Abashin, V G; Polovinka, V S

    2014-05-01

    The article is devoted to activity of the Central Military Hospital of the People's Commissariat for Defence during the Great Patriotic War. The research is based on declassified orders of PCD and orders of the chef of hospital. Authors presented the role of the hospital in organization of medical aid for officers of PCD, members of their families, Red Army soldiers, junior and senior Red Army commanders; the role of the hospital in organization of medical facilities for combat army; medical supply for evacuation of family members of PCD's officers ( en route and in evacuation places); delivery of child health care to children of officers of PCD in the hospital and education in kindergartens of PCD. PMID:25286563

  6. A Not-So-Gentle Refutation of the Defence of Homeopathy.

    PubMed

    Zawiła-Niedźwiecki, Jakub; Olender, Jacek

    2016-03-01

    In a recent paper, Levy, Gadd, Kerridge, and Komesaroff attempt to defend the ethicality of homeopathy by attacking the utilitarian ethical framework as a basis for medical ethics and by introducing a distinction between evidence-based medicine and modern science. This paper demonstrates that their argumentation is not only insufficient to achieve that goal but also incorrect. Utilitarianism is not required to show that homeopathic practice is unethical; indeed, any normative basis of medical ethics will make it unethical, as a defence of homeopathic practice requires the rejection of modern natural sciences, which are an integral part of medical ethics systems. This paper also points out that evidence-based medicine lies at the very core of modern science. Particular arguments made by Levy et al. within the principlist medical ethics normative system are also shown to be wrong. PMID:26732397

  7. A Review of Filovirus Work and Facilities at The Defence Science and Technology Laboratory Porton Down

    PubMed Central

    Smither, Sophie J.; Lever, Mark S.

    2012-01-01

    Porton Down houses two separate sites capable of conducting high containment research on ACDP (Advisory Committee on Dangerous Pathogens) Hazard Group 4 agents: the Defence Science and Technology Laboratory (Dstl) and the Health Protection Agency (HPA), and filovirus research has been performed at Porton Down since the first Marburg virus disease outbreak in 1967. All work is conducted within primary containment either within cabinet lines (for in vitro work) or large rigid half-suit isolators (for in vivo work). There are extensive aerobiological facilities at high containment and the use of these facilities will be reported. Research at Dstl is primarily focused on assessing and quantifying the hazard, and testing the efficacy of medical countermeasures against filoviruses. Fundamental research directed to the study and understanding of the infectious and pathogenic nature of the filoviruses, particularly in aerosols, will be reported. PMID:23012627

  8. Additive effect of alcohol and nicotine on lipid peroxidation and antioxidant defence mechanism in rats.

    PubMed

    Ashakumary, L; Vijayammal, P L

    1996-01-01

    Cigarette smoking has been established as a major risk factor for atherosclerosis and also for lung cancer. Nicotine is one of the major toxic components of cigarette smoke that is believed to be partly responsible for the deleterious effect of cigarette smoke. Alcohol intake is another major risk factor for the development of cardiovascular disease. Lipid peroxidation is a process associated with the pathogenesis of atherosclerosis. The concentration of lipid peroxides is found to be increased in alcohol-treated rats. On nicotine administration along with alcohol, an additive effect was observed in lipid peroxidation and the antioxidant defence mechanism. The activity of scavenging enzymes superoxide dismutase, catalase and glutathione reductase was found to be decreased, while the activity of glutathione peroxidase and the concentration of glutathione were increased. PMID:8854216

  9. Biochemical activities of berberine, palmatine and sanguinarine mediating chemical defence against microorganisms and herbivores.

    PubMed

    Schmeller, T; Latz-Brüning, B; Wink, M

    1997-01-01

    The alkaloids berberine, palmatine and sanguinarine are toxic to insects and vertebrates and inhibit the multiplication of bacteria, fungi and viruses. Biochemical properties which may contribute to these allelochemical activities were analysed. Acetylcholine esterase, butyrylcholinesterase, choline acetyl transferase, alpha 1- and alpha 2-adrenergic, nicotinergic, muscarinergic and serotonin2 receptors were substantially affected. Sanguinarine appears to be the most effective inhibitor of choline acetyl-transferase (IC50 284 nM), while the protoberberines were inactive at this target. Berberine and palmatine were most active at the alpha 2-receptor (binding with IC50 476 and 956 nM, respectively). Furthermore, berberine and sanguinarine intercalate DNA, inhibit DNA synthesis and reverse transcriptase. In addition, sanguinarine (but not berberine) affects membrane permeability and berberine protein biosynthesis. In consequence, these biochemical activities may mediate chemical defence against microorganisms, viruses and herbivores in the plants producing these alkaloids.

  10. Specific Cues Associated With Honey Bee Social Defence against Varroa destructor Infested Brood

    PubMed Central

    Mondet, Fanny; Kim, Seo Hyun; de Miranda, Joachim R.; Beslay, Dominique; Le Conte, Yves; Mercer, Alison R.

    2016-01-01

    Social immunity forms an essential part of the defence repertoire of social insects. In response to infestation by the parasitic mite Varroa destructor and its associated viruses, honey bees (Apis mellifera L.) have developed a specific behaviour (varroa-sensitive hygiene, or VSH) that helps protect the colony from this parasite. Brood cells heavily infested with mites are uncapped, the brood killed, and the cell contents removed. For this extreme sacrifice to be beneficial to the colony, the targeting of parasitized brood for removal must be accurate and selective. Here we show that varroa-infested brood produce uniquely identifiable cues that could be used by VSH-performing bees to identify with high specificity which brood cells to sacrifice. This selective elimination of mite-infested brood is a disease resistance strategy analogous to programmed cell death, where young bees likely to be highly dysfunctional as adults are sacrificed for the greater good of the colony. PMID:27140530

  11. The Defence of Artificial Life by Synthetic Biology From Ethical and Social Aspects.

    PubMed

    Chen, Yiyi; Yin, Zhou; Shao, Zhexin; Xie, Qiong

    2015-07-01

    Synthetic biology opens up exciting new opportunities for research and industry. Although the work of synthetic biologists presents many beneficial applications, it also raises potentially serious ethical concerns. Therefore, clear ideas must be formed regarding its ethical and social implications, e.g., public perception, safety, security, intellectual property rights and so on. In this review, the authors identified four issues relevant to synthetic biology and discussed associated ethical and practical implications. By weighing these perspectives of all sides, this paper clarifies the point that synthetic biology, as an emerging discipline with many anticipated benefits and positive impacts on society, can acquire moral support and ethical defence. Therefore, synthetic biologists should not be shackled with heavy ethical chains, but we must ensure that research is conducted under strict control and effective supervisory methods.

  12. A Simplified Guidance for Target Missiles Used in Ballistic Missile Defence Evaluation

    NASA Astrophysics Data System (ADS)

    Prabhakar, N.; Kumar, I. D.; Tata, S. K.; Vaithiyanathan, V.

    2013-01-01

    A simplified guidance scheme for the target missiles used in Ballistic Missile Defence is presented in this paper. The proposed method has two major components, a Ground Guidance Computation (GGC) and an In-Flight Guidance Computation. The GGC which runs on the ground uses a missile model to generate attitude history in pitch plane and computes launch azimuth of the missile to compensate for the effect of earth rotation. The vehicle follows the pre launch computed attitude (theta) history in pitch plane and also applies the course correction in azimuth plane based on its deviation from the pre launch computed azimuth plane. This scheme requires less computations and counters In-flight disturbances such as wind, gust etc. quite efficiently. The simulation results show that the proposed method provides the satisfactory performance and robustness.

  13. Phagocytosis mediates specificity in the immune defence of an invertebrate, the woodlouse Porcellio scaber (Crustacea: Isopoda).

    PubMed

    Roth, Olivia; Kurtz, Joachim

    2009-11-01

    Specificity and memory are the hallmarks of the adaptive immune system of vertebrates. However, phenomena of specificity upon priming of immunity have recently been demonstrated also in invertebrates, which rely exclusively on innate immune defence. It has been suggested that phagocytosis might represent a core candidate for such specificity in invertebrates. We here developed in vitro phagocytosis measurements for different bacteria in the woodlouse Porcellio scaber (Crustacea: Isopoda). After immune priming with heat-killed bacteria, hemocytes showed increased phagocytosis of a previously encountered bacterial strain compared to other bacteria. These data support the role of phagocytosis in invertebrate immunological specificity and suggest a high degree of specificity that even enables to differentiate between strains of the same bacterial species.

  14. Divergence in Defence against Herbivores between Males and Females of Dioecious Plant Species

    PubMed Central

    Avila-Sakar, Germán; Romanow, Cora Anne

    2012-01-01

    Defensive traits may evolve differently between sexes in dioecious plant species. Our current understanding of this process hinges on a partial view of the evolution of resistance traits that may result in male-biased herbivory in dioecious populations. Here, we present a critical summary of the current state of the knowledge of herbivory in dioecious species and propose alternative evolutionary scenarios that have been neglected. These scenarios consider the potential evolutionary and functional determinants of sexual dimorphism in patterns of resource allocation to reproduction, growth, and defence. We review the evidence upon which two previous reviews of sex-biased herbivory have concluded that male-biased herbivory is a rule for dioecious species, and we caution readers about a series of shortcomings of many of these studies. Lastly, we propose a minimal standard protocol that should be followed in any studies that intend to elucidate the (co)evolution of interactions between dioecious plants and their herbivores. PMID:23320247

  15. A Not-So-Gentle Refutation of the Defence of Homeopathy.

    PubMed

    Zawiła-Niedźwiecki, Jakub; Olender, Jacek

    2016-03-01

    In a recent paper, Levy, Gadd, Kerridge, and Komesaroff attempt to defend the ethicality of homeopathy by attacking the utilitarian ethical framework as a basis for medical ethics and by introducing a distinction between evidence-based medicine and modern science. This paper demonstrates that their argumentation is not only insufficient to achieve that goal but also incorrect. Utilitarianism is not required to show that homeopathic practice is unethical; indeed, any normative basis of medical ethics will make it unethical, as a defence of homeopathic practice requires the rejection of modern natural sciences, which are an integral part of medical ethics systems. This paper also points out that evidence-based medicine lies at the very core of modern science. Particular arguments made by Levy et al. within the principlist medical ethics normative system are also shown to be wrong.

  16. Pella vilya: Near earth objects—Planetary defence through the regulation of resource utilisation

    NASA Astrophysics Data System (ADS)

    Goh, Gérardine Meishan

    2010-07-01

    Reactions to near earth objects (NEOs) in the past decade have run the gamut from expectations of Armageddon-type scenarios to Eureka moments of revolutionary scientific ideas. Concerns over the potentially devastating effects of an unmitigated collision jostle with forecasts of untold economic returns from the utilisation of NEO resources. Drawing from recent analogies and examples from the field of international environmental law, this paper proposes the development of a legal framework for the regulation of NEO resource utilisation. The proposed legal framework also includes a mechanism to ensure the political will and economic investment necessary for technological advances in planetary defence. By twinning the threats and opportunities presented by NEOs, this paper also analyses the position of theme-specific space law development in the overall legal framework of space exploration and traffic management.

  17. Parasitic scabies mites and associated bacteria joining forces against host complement defence.

    PubMed

    Swe, P M; Reynolds, S L; Fischer, K

    2014-11-01

    Scabies is a ubiquitous and contagious skin disease caused by the parasitic mite Sarcoptes scabiei Epidemiological studies have identified scabies as a causative agent for secondary skin infections caused by Staphylococcus aureus and Streptococcus pyogenes. This is an important notion, as such bacterial infections can lead to serious downstream life-threatening complications. As the complement system is the first line of host defence that confronts invading pathogens, both the mite and bacteria produce a large array of molecules that inhibit the complement cascades. It is hypothesised that scabies mite complement inhibitors may play an important role in providing a favourable micro-environment for the establishment of secondary bacterial infections. This review aims to bring together the current literature on complement inhibition by scabies mites and bacteria associated with scabies and to discuss the proposed molecular link between scabies and bacterial co-infections. PMID:25081184

  18. Platelets in neonates: central mediators in haemostasis, antimicrobial defence and inflammation.

    PubMed

    Andres, Oliver; Schulze, Harald; Speer, Christian P

    2015-01-01

    Platelets are not only centrally involved in haemostasis, but also in antimicrobial defence and inflammation. Since evaluation of platelet physiology in the particular patient group of preterm and term neonatal infants is highly restricted for ethical reasons, there are hardly any data available in healthy and much less in extremely immature or ill neonates. By summarising current knowledge and addressing both platelet researchers and neonatologists, we describe neonatal platelet count and morphology, report on previous analyses of neonatal platelet function in primary haemostasis and provide insights into recent advances in platelet immunology that considerably impacts our clinical view on the critically ill neonatal infant. We conclude that neonatal platelets, originating from liver megakaryocytes, substantially differ from adult platelets and may play a pivotal role in the pathophysiology of neonatal sepsis or intraventricular haemorrhage, both complications which seriously augment perinatal morbidity and mortality.

  19. Effects of glutathione modulation on oxidative stress and enzymatic antioxidant defence in yeast Pachysolen tannophilus.

    PubMed

    Saharan, Rajesh K; Sharma, Sukesh C

    2011-03-01

    The aim of this study was to explore the relationship of intracellular glutathione with various oxidative stress markers and the stress protectant marker trehalose. In the first group of yeast cells, diethyl maleate was used for depletion of glutathione. A second group of yeast cells were incubated with amino acids constituting glutathione (GIu, Cys, Gly) to increase glutathione level. Increased level of oxidative stress marker like ROS, protein carbonyl formation and lipid peroxidation and decreased viability in glutathione-depleted cells were observed in the present study. The increased activity of antioxidant enzymes SOD and CAT in the glutathione depleted group suggests the interaction of different antioxidant defence system in Pachysolen tannophilus. Furthermore, the increased levels of trehalose in glutathione-depleted group shows that trehalose acts as a stress reducer in glutathione depleted Pachysolen tannophilus.

  20. Influence of strict regulations on the use of hearing protectors in the Finnish Defence Forces.

    PubMed

    Savolainen, S; Kuokkanen, J T; Lehtomäki, K M

    1999-11-01

    The regulations concerning hearing protection during military training in the Finnish Defence Forces were renewed in 1989. The material of this prospective study concerns 912 consecutive conscripts (463 before and 449 after the new regulations) who were referred to the Central Military Hospital for acute acoustic trauma (AAT). We focused on three issues: (1) general habits regarding the use of hearing protection during shooting drills and combat training; (2) hearing protection at the moment of AAT; and (3) the cause of AAT. In combat training, the use of any hearing protectors was only 50% before the new regulations, but after they came into force the proportion was greater than 90%, and more effective protectors were used. However, at the time of AAT the hearing protection was absent in more than 80% of cases in both groups. The most common cause of AAT was small arms in both groups (83%). PMID:10578597

  1. Air Pollution.

    ERIC Educational Resources Information Center

    Fox, Donald L.

    1989-01-01

    Materials related to air pollution are reviewed for the period January 1987, to October 1988. The topics are pollution monitoring, air pollution, and environmental chemistry. The organization consists of two major analytical divisions: (1) gaseous methods; and (2) aerosol and particulate methods. (MVL)

  2. Air Pollution.

    EPA Science Inventory

    Air quality is affected by many types of pollutants that are emitted from various sources, including stationary and mobile. These sources release both criteria and hazardous air pollutants, which cause health effects, ecological harm, and material damage. They are generally categ...

  3. Comparing efficacy of different taxonomic resolutions and surrogates in detecting changes in soft bottom assemblages due to coastal defence structures.

    PubMed

    Bertasi, Fabio; Colangelo, Marina Antonia; Colosio, Francesco; Gregorio, Gianni; Abbiati, Marco; Ceccherelli, Victor Ugo

    2009-05-01

    Sandy shores on the West coast of the North Adriatic Sea are extensively protected by different types of defence structures to prevent coastal erosion. Coastal defence schemes modify the hydrodynamic regime, the sediment structure and composition thus affecting the benthic assemblages. This study examines the effectiveness in detecting changes in soft bottom assemblages caused by coastal defence structures by using different levels of taxonomic resolution, polychaetes and/or bivalves as surrogates and different data transformations. A synoptic analyses of three datasets of subtidal benthic macrofauna used in studies aimed at assessing the impact of breakwaters along the North Adriatic coast has been done. Analyses of similarities and correlations between distance matrices were done using matrices with different levels of taxonomic resolution, and with polychaetes or bivalves data alone. Lentidium mediterraneum was the most abundant species in all datasets. Its abundance was not consistently related to the presence of defence structures. Moreover, distribution patterns of L. mediterraneum were masking the structure of the whole macrofaunal assemblages. Removal of L. mediterraneum from the datasets allowed the detection of changes in benthic assemblages due to coastal defences. Analyses on different levels of taxonomic resolution showed that the level of family maintained sufficient information to detect the impacts of coastal defence structures on benthic assemblages. Moreover, the outcomes depended on the transformation used. Patterns of distribution of bivalves, used as surrogates, showed low correlations with the patterns of the total macrofaunal species assemblages. Patterns of polychaetes, if identified to the species or genus level showed higher correlations with the whole dataset. However, the identification of polychaetes to species and genus level is as costly as the identification of all macrobenthic taxa at family level. This study provided additional

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

    PubMed

    Hussain, Abid; Rizwan-Ul-Haq, Muhammad; Al-Ayedh, Hassan; AlJabr, Ahmed Mohammed

    2016-01-01

    Insects infected with entomopathogenic fungi, experience physiological changes that influence their growth and immune defence. The potential of nine isolates of entomopathogenic fungi was evaluated after determining percent germination and relative conidial hydrophobicity. However, nutritional indices were evaluated after immersing eighth-instar Rhynchophorus ferrugineus larvae into each isolate suspension (1 × 10⁷ conidia/mL). The results showed that isolates B6884 and M9374 had 44.51% and 39.02% higher conidial hydrophobicity compared with isolate I03011 (least virulent). The results of nutritional index assays revealed a significant reduction in growth indices after infection with different isolates. Compared with control, B6884 and M9374 greatly decreased larval growth by reducing the efficacy of conversion of ingested food (36%-47%) and Efficacy of conversion of digested food (50%-63%). Furthermore, only isolate B6884 induced 100% mortality within 12 days. Compared with control, isolate I03011, possessing the lowest conidial hydrophobicity, only reduced 0.29% of the efficacy of conversion of ingested food (ECI) and 0.48% of the efficacy of conversion of digested food (ECD). Similarly, transcriptomic analysis of genes related to the Red palm weevil (RPW) immune response, including pathogen recognition receptors (C-type lectin and endo-beta-1,4-glucanse), signal modulator (Serine protease-like protein), signal transductors (Calmodulin-like protein and EF-hand domain containing protein) and effectors (C-type lysozyme, Cathepsin L., Defensin-like protein, Serine carboxypeptidase, and Thaumatin-like protein), was significantly increased in larval samples infected with B6884 and M9374. These results suggest that for an isolate to be virulent, conidial hydrophobicity and germination should also be considered during pathogen selection, as these factors could significantly impact host growth and immune defence mechanisms. PMID:27618036

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

    PubMed Central

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

    2014-01-01

    Newborn infants are highly susceptible to infection. This defect in host defence has generally been ascribed to the immaturity of neonatal immune cells; however, the degree of hyporesponsiveness is highly variable and depends on the stimulation conditions1–7. These discordant responses illustrate the need for a more unified explanation for why immunity is compromised in neonates. Here we show that physiologically enriched CD71+ erythroid cells in neonatal mice and human cord blood have distinctive immunosuppressive properties. The production of innate immune protective cytokines by adult cells is diminished after transfer to neonatal mice or after co-culture with neonatal splenocytes. Neonatal CD71+ cells express the enzyme arginase-2, and arginase activity is essential for the immunosuppressive properties of these cells because molecular inhibition of this enzyme or supplementation with l-arginine overrides immunosuppression. In addition, the ablation of CD71+ cells in neonatal mice, or the decline in number of these cells as postnatal development progresses parallels the loss of suppression, and restored resistance to the perinatal pathogens Listeria monocytogenes and Escherichia coli8,9. However, CD71+ cell-mediated susceptibility to infection is counterbalanced by CD71+ cell-mediated protection against aberrant immune cell activation in the intestine, where colonization with commensal microorganisms occurs swiftly after parturition10,11.Conversely, circumventing such colonization by using antimicrobials or gnotobiotic germ-free mice overrides these protective benefits. Thus, CD71+ cells quench the excessive inflammation induced by abrupt colonization with commensal microorganisms after parturition. This finding challenges the idea that the susceptibility of neonates to infection reflects immune-cell-intrinsic defects and instead highlights processes that are developmentally more essential and inadvertently mitigate innate immune protection. We anticipate that

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

    PubMed Central

    Kazimírová, Mária; Štibrániová, Iveta

    2013-01-01

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

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

    PubMed Central

    Hussain, Abid; Rizwan-ul-Haq, Muhammad; Al-Ayedh, Hassan; AlJabr, Ahmed Mohammed

    2016-01-01

    Insects infected with entomopathogenic fungi, experience physiological changes that influence their growth and immune defence. The potential of nine isolates of entomopathogenic fungi was evaluated after determining percent germination and relative conidial hydrophobicity. However, nutritional indices were evaluated after immersing eighth-instar Rhynchophorus ferrugineus larvae into each isolate suspension (1 × 107 conidia/mL). The results showed that isolates B6884 and M9374 had 44.51% and 39.02% higher conidial hydrophobicity compared with isolate I03011 (least virulent). The results of nutritional index assays revealed a significant reduction in growth indices after infection with different isolates. Compared with control, B6884 and M9374 greatly decreased larval growth by reducing the efficacy of conversion of ingested food (36%–47%) and Efficacy of conversion of digested food (50%–63%). Furthermore, only isolate B6884 induced 100% mortality within 12 days. Compared with control, isolate I03011, possessing the lowest conidial hydrophobicity, only reduced 0.29% of the efficacy of conversion of ingested food (ECI) and 0.48% of the efficacy of conversion of digested food (ECD). Similarly, transcriptomic analysis of genes related to the Red palm weevil (RPW) immune response, including pathogen recognition receptors (C-type lectin and endo-beta-1,4-glucanse), signal modulator (Serine protease-like protein), signal transductors (Calmodulin-like protein and EF-hand domain containing protein) and effectors (C-type lysozyme, Cathepsin L., Defensin-like protein, Serine carboxypeptidase, and Thaumatin-like protein), was significantly increased in larval samples infected with B6884 and M9374. These results suggest that for an isolate to be virulent, conidial hydrophobicity and germination should also be considered during pathogen selection, as these factors could significantly impact host growth and immune defence mechanisms. PMID:27618036

  8. PTU-induced hypothyroidism modulates antioxidant defence status in the developing cerebellum.

    PubMed

    Bhanja, S; Chainy, G B N

    2010-05-01

    The objective of the present study was to evaluate the effect of 6-n-propylthiouracil (PTU)-induced hypothyroidism on oxidative stress parameters, expression of antioxidant defence enzymes, cell proliferation and apoptosis in the developing cerebellum. PTU challenged neonates showed significant decrease in serum T(3) and T(4) levels and marked increase in TSH levels. Significantly elevated levels of cerebellar H(2)O(2) and lipid peroxidation were observed in 7 days old hypothyroid rats, along with increased activities of superoxide dismutase and glutathione peroxidase and decline in catalase activity. In 30 days old hypothyroid rats, a significant decline in cerebellar lipid peroxidation, superoxide dismutase and glutathione peroxidase activity and expression was observed along with an up-regulation in catalase activity and expression. Expression of antioxidant enzymes was studied by Western blot and semi-quantitative rt-PCR. A distinct increase in cell proliferation as indicated by proliferating cell nuclear antigen (PCNA) immunoreactivity was observed in the internal granular layer of cerebellum of 7 days old hypothyroid rats and significant drop in PCNA positive cells in the cerebellar molecular layer and internal granular layer of 30 days old PTU treated rats as compared to controls. In situ end labeling by TUNEL assay showed increased apoptosis in cerebellum of hypothyroid rats in comparison to controls. These results suggest that the antioxidant defence system of the developing cerebellum is sensitive to thyroid hormone deficiency and consequent alterations in oxidative stress status may play a role in regulation of cell proliferation of the cerebellum during neonatal brain development.

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

    PubMed

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

    2016-01-01

    Trypanosoma cruzi, the causative agent of Chagas disease, is an obligatory intracellular parasite with a digenetic life cycle. Due to the variety of host environments, it faces several sources of oxidative stress. In addition to reactive oxygen species (ROS) produced by its own metabolism, T. cruzi must deal with high ROS levels generated as part of the host's immune responses. Hence, the conclusion that T. cruzi has limited ability to deal with ROS (based on the lack of a few enzymes involved with oxidative stress responses) seems somewhat paradoxical. Actually, to withstand such variable sources of oxidative stress, T. cruzi has developed complex defence mechanisms. This includes ROS detoxification pathways that are distinct from the ones in the mammalian host, DNA repair pathways and specialized polymerases, which not only protect its genome from the resulting oxidative damage but also contribute to the generation of genetic diversity within the parasite population. Recent studies on T. cruzi's DNA repair pathways as mismatch repair (MMR) and GO system suggested that, besides a role associated with DNA repair, some proteins of these pathways may also be involved in signalling oxidative damage. Recent data also suggested that an oxidative environment might be beneficial for parasite survival within the host cell as it contributes to iron mobilization from the host's intracellular storages. Besides contributing to the understanding of basic aspects of T. cruzi biology, these studies are highly relevant since oxidative stress pathways are part of the poorly understood mechanisms behind the mode of action of drugs currently used against this parasite. By unveiling new peculiar aspects of T. cruzi biology, emerging data on DNA repair pathways and other antioxidant defences from this parasite have revealed potential new targets for a much needed boost in drug development efforts towards a better treatment for Chagas disease. PMID:27036062

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

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

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

  11. Endophytic Bacillus spp. produce antifungal lipopeptides and induce host defence gene expression in maize.

    PubMed

    Gond, Surendra K; Bergen, Marshall S; Torres, Mónica S; White, James F

    2015-03-01

    Endophytes are mutualistic symbionts within healthy plant tissues. In this study we isolated Bacillus spp. from seeds of several varieties of maize. Bacillus amyloliquifaciens or Bacillus subtilis were found to be present in all maize varieties examined in this study. To determine whether bacteria may produce antifungal compounds, generally lipopeptides in Bacillus spp., bacterial cultures were screened for production of lipopeptides. Lipopeptides were extracted by acid precipitation from liquid cultures of Bacillus spp. Lipopeptide extracts from Bacillus spp. isolated from Indian popcorn and yellow dent corn showed inhibitory activity against Fusarium moniliforme at 500μg per disk. Using MALDI-TOF mass spectrometry we detected the presence of antifungal iturin A, fengycin and bacillomycin in these isolates. PCR amplification also showed the presence of genes for iturin A and fengycin. B. subtilis (SG_JW.03) isolated from Indian popcorn showed strong inhibition of Arabidopsis seed mycoflora and enhanced seedling growth. We tested for the induction of defence gene expression in the host plant after treatment of plants with B. subtilis (SG_JW.03) and its lipopeptide extract using RT-qPCR. Roots of Indian popcorn seedlings treated with a suspension of B. subtilis (SG_JW.03) showed the induction of pathogenesis-related genes, including PR-1 and PR-4, which relate to plant defence against fungal pathogens. The lipopeptide extract alone did not increase the expression of these pathogenesis-related genes. Based on our study of maize endophytes, we hypothesize that, bacterial endophytes that naturally occur in many maize varieties may function to protect hosts by secreting antifungal lipopeptides that inhibit pathogens as well as inducing the up-regulation of pathogenesis-related genes of host plants (systemic acquired resistance). PMID:25497916

  12. Changes in the antioxidant defence and in selenium concentration in tissues of vanadium exposed rats.

    PubMed

    Sanchez-Gonzalez, Cristina; Bermudez-Peña, Carmen; Trenzado, Cristina E; Goenaga-Infante, Heidi; Montes-Bayon, María; Sanz-Medel, Alfredo; Llopis, Juan

    2012-08-01

    Vanadium is an element whose role as a micronutrient for humans is not yet completely established, but which has been shown to possess hypoglycaemic properties in diabetes. In an earlier study, we showed that in STZ-diabetic rats, exposure to 1 mg V per day has no effect on glycaemia or on antioxidant status. When the exposure was raised to 3 mg V per day there was a hypoglycaemic effect, together with reduced Se in the tissues, which reduced antioxidant defences. The aim of the present study was to examine whether exposure to 1 mg V per day modifies Se nutritional status and/or antioxidant defences in healthy rats. Two groups of rats were examined: control and vanadium-treated. Vanadium, as bis(maltolato)oxovanadium(iv), was supplied in the drinking water. The experiment had a duration of five weeks. Selenium was measured in excreta, serum, skeletal muscle, kidneys, liver, heart, femur and adipose tissue. Number of red (RBC) and white (WBC) blood cells and haemoglobin (Hb) were determined in samples of whole blood. Glutathione peroxidase (GPx), glutathione transferase (GST), catalase (CAT) and NAD(P)H:quinine-oxidoreductase1 (NQO1) activity, and malondialdehyde (MDA) in the liver were evaluated. Treatment significantly reduced food intake, produced an anaemic state, and decreased Se absorption and Se content in serum, kidneys and the liver. GPx, GST and NQO1 activity were decreased in the liver, while MDA levels rose. We conclude that healthy rats are more sensitive than diabetic ones to the effects of V. This should be taken into account for populations that are particularly exposed to V for environmental reasons, and/or that consume V as a nutritional supplement.

  13. Antioxidant defence and stress protein induction following heat stress in the Mediterranean snail Xeropicta derbentina.

    PubMed

    Troschinski, Sandra; Dieterich, Andreas; Krais, Stefanie; Triebskorn, Rita; Köhler, Heinz-R

    2014-12-15

    The Mediterranean snail Xeropicta derbentina (Pulmonata, Hygromiidae), being highly abundant in Southern France, has the need for efficient physiological adaptations to desiccation and over-heating posed by dry and hot environmental conditions. As a consequence of heat, oxidative stress manifests in these organisms, which, in turn, leads to the formation of reactive oxygen species (ROS). In this study, we focused on adaptations at the biochemical level by investigation of antioxidant defences and heat shock protein 70 (Hsp70) induction, both essential mechanisms of the heat stress response. We exposed snails to elevated temperature (25, 38, 40, 43 and 45°C) in the laboratory and measured the activity of the antioxidant enzymes catalase (CAT) and glutathione peroxidase (GPx), determined the Hsp70 level and quantified lipid peroxidation. In general, we found a high constitutive level of CAT activity in all treatments, which may be interpreted as a permanent protection against ROS, i.e. hydrogen peroxide. CAT and GPx showed temperature-dependent activity: CAT activity was significantly increased in response to high temperatures (43 and 45°C), whereas GPx exhibited a significantly increased activity at 40°C, probably in response to high levels of lipid peroxides that occurred in the 38°C treatment. Hsp70 showed a maximum induction at 40°C, followed by a decrease at higher temperatures. Our results reveal that X. derbentina possesses a set of efficient mechanisms to cope with the damaging effects of heat. Furthermore, we demonstrated that, besides the well-documented Hsp70 stress response, antioxidant defence plays a crucial role in the snails' competence to survive extreme temperatures.

  14. Testing phenotypic trade-offs in the chemical defence strategy of Scots pine under growth-limiting field conditions.

    PubMed

    Villari, Caterina; Faccoli, Massimo; Battisti, Andrea; Bonello, Pierluigi; Marini, Lorenzo

    2014-09-01

    Plants protect themselves from pathogens and herbivores through fine-tuned resource allocation, including trade-offs among resource investments to support constitutive and inducible defences. However, empirical research, especially concerning conifers growing under natural conditions, is still scarce. We investigated the complexity of constitutive and induced defences in a natural Scots pine (Pinus sylvestris L.) stand under growth-limiting conditions typical of alpine environments. Phenotypic trade-offs at three hierarchical levels were tested by investigating the behaviour of phenolic compounds and terpenoids of outer bark and phloem. We tested resource-derived phenotypic correlations between (i) constitutive and inducible defences vs tree ring growth, (ii) different constitutive defence metabolites and (iii) constitutive concentration and inducible variation of individual metabolites. Tree ring growth was positively correlated only with constitutive concentration of total terpenoids, and no overall phenotypic trade-offs between different constitutive defensive metabolites were found. At the lowest hierarchical level tested, i.e., at the level of relationship between constitutive and inducible variation of individual metabolites, we found that different compounds displayed different behaviours; we identified five different defensive metabolite response types, based on direction and strength of the response, regardless of tree age and growth rate. Therefore, under growth-limiting field conditions, Scots pine appears to utilize varied and complex outer bark and phloem defence chemistry, in which only part of the constitutive specialized metabolism is influenced by tree growth, and individual components do not appear to be expressed in a mutually exclusive manner in either constitutive or inducible metabolism.

  15. Air Pollution

    MedlinePlus

    ... tobacco smoke. How is air pollution linked to climate change? While climate change is a global process, it ... ozone levels are also a concern. Impacts of Climate Change on Human Health in the United States: A ...

  16. Air Apparent.

    ERIC Educational Resources Information Center

    Harbster, David A.

    1988-01-01

    Explains the principle upon which a barometer operates. Describes how to construct two barometric devices for use in the classroom that show air's changing pressure. Cites some conditions for predicting weather. (RT)

  17. Urban air

    NASA Astrophysics Data System (ADS)

    Showstack, Randy

    Air pollution and the risk of potential health effects are not sufficiently convincing reasons for people to stop driving their cars, according to a study by the Population Reference Bureau (PRB) released on November 18.While sufficient levels of suspended particulate matter, carbon monoxide, and lead can present health concerns, the study found that many people surveyed for the study were not convinced of the clear linkage between air pollution and health.

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

    PubMed Central

    2011-01-01

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

  19. Hydrogen Peroxide Induced Cell Death: The Major Defences Relative Roles and Consequences in E. coli.

    PubMed

    Uhl, Lionel; Dukan, Sam

    2016-01-01

    We recently developed a mathematical model for predicting reactive oxygen species (ROS) concentration and macromolecules oxidation in vivo. We constructed such a model using Escherichia coli as a model organism and a set of ordinary differential equations. In order to evaluate the major defences relative roles against hydrogen peroxide (H2 O2), we investigated the relative contributions of the various reactions to the dynamic system and searched for approximate analytical solutions for the explicit expression of changes in H2 O2 internal or external concentrations. Although the key actors in cell defence are enzymes and membrane, a detailed analysis shows that their involvement depends on the H2 O2 concentration level. Actually, the impact of the membrane upon the H2 O2 stress felt by the cell is greater when micromolar H2 O2 is present (9-fold less H2 O2 in the cell than out of the cell) than when millimolar H2 O2 is present (about 2-fold less H2 O2 in the cell than out of the cell). The ratio between maximal external H2 O2 and internal H2 O2 concentration also changes, reducing from 8 to 2 while external H2 O2 concentration increases from micromolar to millimolar. This non-linear behaviour mainly occurs because of the switch in the predominant scavenger from Ahp (Alkyl Hydroperoxide Reductase) to Cat (catalase). The phenomenon changes the internal H2 O2 maximal concentration, which surprisingly does not depend on cell density. The external H2 O2 half-life and the cumulative internal H2 O2 exposure do depend upon cell density. Based on these analyses and in order to introduce a concept of dose response relationship for H2 O2-induced cell death, we developed the concepts of "maximal internal H2 O2 concentration" and "cumulative internal H2 O2 concentration" (e.g. the total amount of H2 O2). We predict that cumulative internal H2 O2 concentration is responsible for the H2 O2-mediated death of bacterial cells. PMID:27494019

  20. Hydrogen Peroxide Induced Cell Death: The Major Defences Relative Roles and Consequences in E. coli

    PubMed Central

    Uhl, Lionel; Dukan, Sam

    2016-01-01

    We recently developed a mathematical model for predicting reactive oxygen species (ROS) concentration and macromolecules oxidation in vivo. We constructed such a model using Escherichia coli as a model organism and a set of ordinary differential equations. In order to evaluate the major defences relative roles against hydrogen peroxide (H2 O2), we investigated the relative contributions of the various reactions to the dynamic system and searched for approximate analytical solutions for the explicit expression of changes in H2 O2 internal or external concentrations. Although the key actors in cell defence are enzymes and membrane, a detailed analysis shows that their involvement depends on the H2 O2 concentration level. Actually, the impact of the membrane upon the H2 O2 stress felt by the cell is greater when micromolar H2 O2 is present (9-fold less H2 O2 in the cell than out of the cell) than when millimolar H2 O2 is present (about 2-fold less H2 O2 in the cell than out of the cell). The ratio between maximal external H2 O2 and internal H2 O2 concentration also changes, reducing from 8 to 2 while external H2 O2 concentration increases from micromolar to millimolar. This non-linear behaviour mainly occurs because of the switch in the predominant scavenger from Ahp (Alkyl Hydroperoxide Reductase) to Cat (catalase). The phenomenon changes the internal H2 O2 maximal concentration, which surprisingly does not depend on cell density. The external H2 O2 half-life and the cumulative internal H2 O2 exposure do depend upon cell density. Based on these analyses and in order to introduce a concept of dose response relationship for H2 O2-induced cell death, we developed the concepts of “maximal internal H2 O2 concentration” and “cumulative internal H2 O2 concentration” (e.g. the total amount of H2 O2). We predict that cumulative internal H2 O2 concentration is responsible for the H2 O2-mediated death of bacterial cells. PMID:27494019

  1. An Indirect Defence Trait Mediated through Egg-Induced Maize Volatiles from Neighbouring Plants

    PubMed Central

    Mutyambai, Daniel M.; Bruce, Toby J. A.; van den Berg, Johnnie; Midega, Charles A. O.; Pickett, John A.; Khan, Zeyaur R.

    2016-01-01

    and C. sesamiae parasitic wasps indicated that these parasitoids preferred volatiles from oviposited and neighbouring landrace plants compared to those from the control plants. This effect was absent in the standard commercial hybrid we tested. There was no HIPV induction and no difference in parasitoid attraction in neighbouring and control hybrid maize plants. These results show plant-plant signalling: ‘Nyamula’ maize plants emitting oviposition-induced volatiles attractive to the herbivore’s natural enemies can induce this indirect defence trait in conspecific neighbouring undamaged maize plants. Maize plants growing in a field may thus benefit from this indirect defence through airborne signalling which may enhance the fitness of the volatile-emitting plant by increasing predation pressure on herbivores. PMID:27392034

  2. Antioxidant defences and oxidative damage in salt-treated olive plants under contrasting sunlight irradiance.

    PubMed

    Melgar, Juan Carlos; Guidi, Lucia; Remorini, Damiano; Agati, Giovanni; Degl'innocenti, Elena; Castelli, Silvana; Camilla Baratto, Maria; Faraloni, Cecilia; Tattini, Massimiliano

    2009-09-01

    The interactive effects of root-zone salinity and sunlight on leaf biochemistry, with special emphasis on antioxidant defences, were analysed in Olea europaea L. cv. Allora, during the summer period. Plants were grown outside under 15% (shade plants) or 100% sunlight (sun plants) and supplied with 0 or 125 mM NaCl. The following measurements were performed: (1) the contribution of ions and soluble carbohydrates to osmotic potentials; (2) the photosystem II (PSII) photochemistry and the photosynthetic pigment concentration; (3) the concentration and the tissue-specific distribution of leaf flavonoids; (4) the activity of antioxidant enzymes; and (5) the leaf oxidative damage. The concentrations of Na(+) and Cl(-) were significantly greater in sun than in shade leaves, as also observed for the concentration of the 'antioxidant' sugar-alcohol mannitol. The de-epoxidation state of violaxanthin-cycle pigments increased in response to salinity stress in sun leaves. This finding agrees with a greater maximal PSII photochemistry (F(v)/F(m)) at midday, detected in salt-treated than in control plants, growing in full sunshine. By contrast, salt-treated plants in the shade suffered from midday depression in F(v)/F(m) to a greater degree than that observed in control plants. The high concentration of violaxanthin-cycle pigments in sun leaves suggests that zeaxanthin may protect the chloroplast from photo-oxidative damage, rather than dissipating excess excitation energy via non-photochemical quenching mechanisms. Dihydroxy B-ring-substituted flavonoid glycosides accumulate greatly in the mesophyll, not only in the epidermal cells, in response to high sunlight. The activity of antioxidant enzymes varied little because of sunlight irradiance, but declined sharply in response to high salinity in shade leaves. Interestingly, control and particularly salt-treated plants in the shade underwent greater oxidative damage than their sunny counterparts. These findings, which conform to

  3. An Indirect Defence Trait Mediated through Egg-Induced Maize Volatiles from Neighbouring Plants.

    PubMed

    Mutyambai, Daniel M; Bruce, Toby J A; van den Berg, Johnnie; Midega, Charles A O; Pickett, John A; Khan, Zeyaur R

    2016-01-01

    . sesamiae parasitic wasps indicated that these parasitoids preferred volatiles from oviposited and neighbouring landrace plants compared to those from the control plants. This effect was absent in the standard commercial hybrid we tested. There was no HIPV induction and no difference in parasitoid attraction in neighbouring and control hybrid maize plants. These results show plant-plant signalling: 'Nyamula' maize plants emitting oviposition-induced volatiles attractive to the herbivore's natural enemies can induce this indirect defence trait in conspecific neighbouring undamaged maize plants. Maize plants growing in a field may thus benefit from this indirect defence through airborne signalling which may enhance the fitness of the volatile-emitting plant by increasing predation pressure on herbivores. PMID:27392034

  4. γ-Aminobutyric acid induces resistance against Penicillium expansum by priming of defence responses in pear fruit.

    PubMed

    Yu, Chen; Zeng, Lizhen; Sheng, Kuang; Chen, Fangxia; Zhou, Tao; Zheng, Xiaodong; Yu, Ting

    2014-09-15

    The results from this study showed that treatment with γ-aminobutyric acid (GABA), at 100-1000 μg/ml, induced strong resistance against blue mould rot caused by Penicillium expansum in pear fruit. Moreover, the activities of five defence-related enzymes (including chitinase, β-1,3-glucanase, phenylalnine ammonialyase, peroxidase and polyphenol oxidase) and the expression of these corresponding genes were markedly and/or promptly enhanced in the treatment with GABA and inoculation with P. expansum compared with those that were treated with GABA or inoculated with pathogen alone. In addition, the treatment of pear with GABA had little adverse effect on the edible quality of the fruit. To the best of our knowledge, this is the first report that GABA can effectively reduce fungal disease of harvested fruit. Its mechanisms may be closely correlated with the induction of fruit resistance by priming activation and expression of defence-related enzymes and genes upon challenge with pathogen.

  5. Air surveillance

    SciTech Connect

    Patton, G.W.

    1995-06-01

    This section of the 1994 Hanford Site Environmental Report summarizes the air surveillance and monitoring programs currently in operation at that Hanford Site. Atmospheric releases of pollutants from Hanford to the surrounding region are a potential source of human exposure. For that reason, both radioactive and nonradioactive materials in air are monitored at a number of locations. The influence of Hanford emissions on local radionuclide concentrations was evaluated by comparing concentrations measured at distant locations within the region to concentrations measured at the Site perimeter. This section discusses sample collection, analytical methods, and the results of the Hanford air surveillance program. A complete listing of all analytical results summarized in this section is reported separately by Bisping (1995).

  6. Geometric and frequency EMI sounding of estuarine earthen flood defence embankments in Ireland using 1D inversion models

    NASA Astrophysics Data System (ADS)

    Viganotti, Matteo; Jackson, Ruth; Krahn, Hartmut; Dyer, Mark

    2013-05-01

    Earthen flood defence embankments are linear structures, raised above the flood plain, that are commonly used as flood defences in rural settings; these are often relatively old structures constructed using locally garnered material and of which little is known in terms of design and construction. Alarmingly, it is generally reported that a number of urban developments have expanded to previously rural areas; hence, acquiring knowledge about the flood defences protecting these areas has risen significantly in the agendas of basin and asset managers. This paper focusses, by reporting two case studies, on electromagnetic induction (EMI) methods that would efficiently complement routine visual inspections and would represent a first step to more detailed investigations. Evaluation of the results is presented by comparison with ERT profiles and intrusive investigation data. The EM data, acquired using a GEM-2 apparatus for frequency sounding and an EM-31 apparatus for geometrical sounding, has been handled using the prototype eGMS software tool, being developed by the eGMS international research consortium; the depth sounding data interpretation was assisted by 1D inversions obtained with the EM1DFM software developed by the University of British Columbia. Although both sounding methods showed some limitations, the models obtained were consistent with ERT models and the techniques were useful screening methods for the identification of areas of interest, such as material interfaces or potential seepage areas, within the embankment structure: 1D modelling improved the rapid assessment of earthen flood defence embankments in an estuarine environment; evidence that EMI sounding could play an important role as a monitoring tool or as a first step towards more detailed investigations.

  7. Low temperature induced defence gene expression in winter wheat in relation to resistance to snow moulds and other wheat diseases.

    PubMed

    Gaudet, D A; Wang, Y; Frick, M; Puchalski, B; Penniket, C; Ouellet, T; Robert, L; Singh, J; Laroche, A

    2011-01-01

    Cold hardening of winter wheat at 2 °C for 1-6 wks increased resistance to the snow mould pathogens LTB, Typhula incarnata, and Microdochium nivale as well as to powdery mildew (Blumaria graminis f. sp. graminis) and stripe rust (Puccinia striiformis). Using microarrays and hardening of winter wheat for 0.25, 0.5, 1, 7, 21 and 49 d, an upregulation of a wide range of stress-response genes that include defence-related and abiotic stress-related genes, transcription factors including several lipoxygenases and ethylene responsive factors, and WRKY genes was observed. For the majority of these genes, the upregulation occurred later in the 21-49 d hardening treatments and coincided with the highest expression levels of snow mould resistance. Defence-related sequences were upregulated to a greater extent and were more numerous in the snow mould resistant line CI14106 compared to cold hardy DH+268. Transcript profiling of candidate defence and other stress-related genes under prolonged conditions at -3 °C with or without snow mould infection showed that there was a decline in transcripts of the defence-related genes PR1.1b and NPR3 during the 12wks incubation. Additionally, 14 d hardening was insufficient to permit full expression of the jasmonic acid synthesis gene, allene oxide synthase (AOS) and the fructan degrading enzyme β-fructofuranosidase compared the 42 d hardening treatment. The snow mould resistant line CI14106 was able to maintain higher transcript levels of AOS for longer conditions compared to the susceptible line Norstar under artificial snow mould conditions. These results explain the nature of cold-induced resistance to snow moulds and provide direction on establishing selection criteria for improving resistance and cold tolerance in winter wheat.

  8. Interactive effects of early and later nutritional conditions on the adult antioxidant defence system in zebra finches.

    PubMed

    Noguera, José C; Monaghan, Pat; Metcalfe, Neil B

    2015-07-01

    In vertebrates, antioxidant defences comprise a mixture of endogenously produced components and exogenously obtained antioxidants that are derived mostly from the diet. It has been suggested that early-life micronutritional conditions might influence the way in which the antioxidant defence system operates, which could enable individuals to adjust the activity of the endogenous and exogenous components in line with their expected intake of dietary antioxidants if the future environment resembles the past. We investigated this possibility by experimentally manipulating the micronutrient content of the diet during different periods of postnatal development in the zebra finch (Taeniopygia guttata). Birds that had a low micronutrient diet during the growth phase initially had a lower total antioxidant capacity (TAC) than those reared under a high micronutrient diet, but then showed a compensatory response, so that by the end of the growth phase, the TAC of the two groups was the same. Interestingly, we found an interactive effect of micronutrient intake early and late in development: only those birds that continued with the same dietary treatment (low or high) throughout development showed a significant increase in their TAC during the period of sexual maturation. A similar effect was also found in the level of enzymatic antioxidant defences (glutathione peroxidase; GPx). No significant effects were found in the level of oxidative damage in lipids [malondialdehyde (MDA) levels]. These findings demonstrate the importance of early and late developmental conditions in shaping multiple aspects of the antioxidant system. Furthermore, they suggest that young birds may adjust their antioxidant defences to enable them to 'thrive' on diets rich or poor in micronutrients later in life.

  9. Evidence for aggressive mimicry in an adult brood parasitic bird, and generalized defences in its host.

    PubMed

    Feeney, W E; Troscianko, J; Langmore, N E; Spottiswoode, C N

    2015-07-01

    Mimicry of a harmless model (aggressive mimicry) is used by egg, chick and fledgling brood parasites that resemble the host's own eggs, chicks and fledglings. However, aggressive mimicry may also evolve in adult brood parasites, to avoid attack from hosts and/or manipulate their perception of parasitism risk. We tested the hypothesis that female cuckoo finches (Anomalospiza imberbis) are aggressive mimics of female Euplectes weavers, such as the harmless, abundant and sympatric southern red bishop (Euplectes orix). We show that female cuckoo finch plumage colour and pattern more closely resembled those of Euplectes weavers (putative models) than Vidua finches (closest relatives); that their tawny-flanked prinia (Prinia subflava) hosts were equally aggressive towards female cuckoo finches and southern red bishops, and more aggressive to both than to their male counterparts; and that prinias were equally likely to reject an egg after seeing a female cuckoo finch or bishop, and more likely to do so than after seeing a male bishop near their nest. This is, to our knowledge, the first quantitative evidence for aggressive mimicry in an adult bird, and suggests that host-parasite coevolution can select for aggressive mimicry by avian brood parasites, and counter-defences by hosts, at all stages of the reproductive cycle. PMID:26063850

  10. Influence of Podophyllum hexandrum on endogenous antioxidant defence system in mice: possible role in radioprotection.

    PubMed

    Mittal, A; Pathania, V; Agrawala, P K; Prasad, J; Singh, S; Goel, H C

    2001-08-01

    Podophyllum hexandrum, a Himalayan herb with known radioprotective and anti-tumour properties, was investigated for its mechanism of action. Glutathione S-transferase (GST), catalase, superoxide dismutase (SOD) activities and lipid peroxidation (LPx) were determined in the liver, jejunum and ileum at various time intervals, with and without the aqueous extract of P. hexandrum rhizome (200 mg/kg b.w. i.p.) in unirradiated and whole body irradiated (10 Gy,-2 h) male Swiss albino mice. Pre-irradiation treatment with P. hexandrum enhanced liver GST (P<0.01) and SOD (P<0.05) at 12 h post irradiation, the intestinal SOD (P<0.00005) at 84 h post irradiation was significantly elevated. However, no significant change was manifested in the catalase activity in the liver, at any of the post irradiation intervals (0, 12 and 84 h). The antioxidant defence with Podophyllum sp. treatment in mice can explain to some extent its protective action manifested in terms of survival against whole body lethal irradiation. However, some other possible mechanisms that may strengthen radioprotective action of the Podophyllum sp. extract need to be investigated further.

  11. An ancestral allele of grapevine transcription factor MYB14 promotes plant defence

    PubMed Central

    Duan, Dong; Fischer, Sabine; Merz, Patrick; Bogs, Jochen; Riemann, Michael; Nick, Peter

    2016-01-01

    Stilbene synthase is a key enzyme for the production of the phytoalexin resveratrol. Some clones of Vitis sylvestris, a wild European grapevine species which is almost extinct, have been shown to accumulate more resveratrol in response to different forms of stress. In the current study, we asked whether the induction of stilbene synthase transcripts in Hoe29, one of the V. sylvestris clones with elevated stilbene inducibility, might result from the elevated induction of the transcription factor MYB14. The MYB14 promoter of Hoe29 and of Ke83 (a second stilbene-inducible genotype) harboured distinct regions and were applied to a promoter–reporter system. We show that stilbene synthase inducibility correlates with differences in the induction of MYB14 transcripts for these two genotypes. Both alleles were induced by UV in a promoter–reporter assay, but only the MYB14 promoter from Hoe29 was induced by flg22, consistent with the stilbene synthase expression of the donor genotypes, where both respond to UV but only Hoe29 is responsive to Plasmopara viticola during defence. We mapped upstream signals and found that a RboH-dependent oxidative burst, calcium influx, a MAPK cascade, and jasmonate activated the MYB14 promoter, whereas salicylic acid was ineffective. Our data suggest that the Hoe29 allele of the MYB14 promoter has potential as a candidate target for resistance breeding. PMID:26842984

  12. Yersinia virulence factors - a sophisticated arsenal for combating host defences.

    PubMed

    Atkinson, Steve; Williams, Paul

    2016-01-01

    The human pathogens Yersinia pseudotuberculosis and Yersinia enterocolitica cause enterocolitis, while Yersinia pestis is responsible for pneumonic, bubonic, and septicaemic plague. All three share an infection strategy that relies on a virulence factor arsenal to enable them to enter, adhere to, and colonise the host while evading host defences to avoid untimely clearance. Their arsenal includes a number of adhesins that allow the invading pathogens to establish a foothold in the host and to adhere to specific tissues later during infection. When the host innate immune system has been activated, all three pathogens produce a structure analogous to a hypodermic needle. In conjunction with the translocon, which forms a pore in the host membrane, the channel that is formed enables the transfer of six 'effector' proteins into the host cell cytoplasm. These proteins mimic host cell proteins but are more efficient than their native counterparts at modifying the host cell cytoskeleton, triggering the host cell suicide response. Such a sophisticated arsenal ensures that yersiniae maintain the upper hand despite the best efforts of the host to counteract the infecting pathogen. PMID:27347390

  13. Business continuity strategies for cyber defence: battling time and information overload.

    PubMed

    Streufert, John

    2010-11-01

    Can the same numbers and letters which are the life blood of modern business and government computer systems be harnessed to protect computers from attack against known information security risks? For the past seven years, Foreign Service officers and technicians of the US Government have sought to maintain diplomatic operations in the face of rising cyber attacks and test the hypothesis that an ounce of prevention is worth a pound of cure. As eight out of ten attacks leverage known computer security vulnerabilities or configuration setting weaknesses, a pound of cure would seem to be easy to come by. Yet modern security tools present an unusually consequential threat to business continuity - too much rather than too little information on cyber problems is presented, harking back to a phenomenon cited by social scientists in the 1960s called 'information overload'. Experience indicates that the longer the most serious cyber problems go untreated, the wider the attack surface adversaries can find. One technique used at the Department of State, called 'risk scoring', resulted in an 89 per cent overall reduction in measured risk over 12 months for the Department of State's servers and personal computers. Later refinements of risk scoring enabled technicians to correct unique security threats with unprecedented speed. This paper explores how the use of metrics, special care in presenting information to technicians and executives alike, as well as tactical use of organisational incentives can result in stronger cyber defences protecting modern organisations.

  14. Quantifying police officers' arrest and self-defence skills: does performance decrease under pressure?

    PubMed

    Nieuwenhuys, Arne; Caljouw, Simone R; Leijsen, Maaike R; Schmeits, Bart A J; Oudejans, Raoul R D

    2009-12-01

    This study investigated police officers' performance on five selected arrest and self-defence skills that are regularly used in the line of duty. In Experiment 1 a 5-point scale to measure skill performance was developed and tested with 14 police instructors. Results showed that the new scale has satisfactory inter-rater reliability and good intra-rater reliability. In Experiment 2, the external and concurrent validity of the scale was tested by measuring the performances of 19 police officers executing the same skills in a high- and a low-pressure environment and comparing the results obtained with the new 5-point scale with results obtained with a currently used binary scale (i.e. sufficient/insufficient). While the scale proved to have good external and concurrent validity, it appeared that the police officers' performance really suffered under pressure. Given the criticality of successful police performance, it is suggested that incorporating psychological factors (e.g. pressure) in training procedures may enhance performance. PMID:19941180

  15. Uncovering the relationship between defence and orienting in emotion: cardiac reactivity to unpleasant pictures.

    PubMed

    Sánchez-Navarro, Juan Pedro; Martínez-Selva, José M; Román, Francisco

    2006-07-01

    This research was aimed at studying the relationship between the cardiovascular reactivity to an intense auditory stimulus and the subsequent cardiac response evoked by affective visual stimuli in fifty-five subjects who underwent a cardiac reactivity task (presentation of an intense acoustic stimulus), followed by a picture viewing task (54 pictures selected from the International Affective Picture System). Heart rate (HR), electrodermal activity and corrugator supercilii electromyographic activity were recorded. Subjects were divided into two groups - high accelerators and low accelerators - on the basis of the first heart rate acceleration obtained in the cardiac reactivity task. Pictures evoked different cardiac response patterns in each subject group. Unpleasant pictures promoted a lower initial HR deceleration and a higher final acceleration in high accelerators than in low accelerators. This pattern of response was more marked with body damage pictures. Moreover, a relationship was found between the first acceleration promoted by the acoustic stimulus and the HR response waveform to the body damage pictures. These results show that, in an unselected sample of subjects, a subgroup tended to respond to loud stimuli with higher HR acceleration and sympathetic activation and to respond defensively to unpleasant pictures (as found by less initial HR deceleration and higher final HR acceleration), rather than manifesting an orienting response. The elicitation of the defence response by a brain fear system, in which the amygdala is a key structure, is also discussed.

  16. The neutral metallopeptidase NMP1 of Trichoderma guizhouense is required for mycotrophy and self-defence.

    PubMed

    Zhang, Jian; Bayram Akcapinar, Gunseli; Atanasova, Lea; Rahimi, Mohammad Javad; Przylucka, Agnieszka; Yang, Dongqing; Kubicek, Christian P; Zhang, Ruifu; Shen, Qirong; Druzhinina, Irina S

    2016-02-01

    Trichoderma guizhouense NJAU 4742 (Harzianum clade) can suppress the causative agent of banana wild disease Fusarium oxysporum f. sp. cubense 4 (Foc4). To identify genes involved in this trait, we used T-DNA insertional mutagenesis and isolated one mutant that was unable to overgrow Foc4 and had reduced antifungal ability. Using the high-efficiency thermal asymmetric interlaced-PCR, the T-DNA was located in the terminator of a neutral metalloprotease gene (encoding a MEROPS family M35 protease), which was named nmp1. The antifungal activity of the mutant was recovered by retransformation with wild-type nmp1 gene. The purified NMP1 (overexpressed in Pichia pastoris) did not inhibit the growth and germination of other fungi in vitro. Its addition, however, partly recovered the antifungal activity of the mutant strain against some fungi. The expression of nmp1 is induced by the presence of fungi and by dead fungal biomass, but the time-course of transcript accumulation following the physical contact depends on mode of interaction: it increases in cases of long-lasting parasitism and decreases if the prey fungus is dead shortly after or even before the contact (predation). We thus conclude that NMP1 protein of T. guizhouense has major importance for mycotrophic interactions and defence against other fungi. PMID:26118314

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

    PubMed

    Thorogood, Rose; Davies, Nicholas B

    2016-01-01

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

  18. Business continuity strategies for cyber defence: battling time and information overload.

    PubMed

    Streufert, John

    2010-11-01

    Can the same numbers and letters which are the life blood of modern business and government computer systems be harnessed to protect computers from attack against known information security risks? For the past seven years, Foreign Service officers and technicians of the US Government have sought to maintain diplomatic operations in the face of rising cyber attacks and test the hypothesis that an ounce of prevention is worth a pound of cure. As eight out of ten attacks leverage known computer security vulnerabilities or configuration setting weaknesses, a pound of cure would seem to be easy to come by. Yet modern security tools present an unusually consequential threat to business continuity - too much rather than too little information on cyber problems is presented, harking back to a phenomenon cited by social scientists in the 1960s called 'information overload'. Experience indicates that the longer the most serious cyber problems go untreated, the wider the attack surface adversaries can find. One technique used at the Department of State, called 'risk scoring', resulted in an 89 per cent overall reduction in measured risk over 12 months for the Department of State's servers and personal computers. Later refinements of risk scoring enabled technicians to correct unique security threats with unprecedented speed. This paper explores how the use of metrics, special care in presenting information to technicians and executives alike, as well as tactical use of organisational incentives can result in stronger cyber defences protecting modern organisations. PMID:21177217

  19. Glutamate receptor-like channels in plants: a role as amino acid sensors in plant defence?

    PubMed Central

    Roberts, Michael R.

    2014-01-01

    Plant glutamate receptor-like genes (GLRs) are homologous to the genes for mammalian ionotropic glutamate receptors (iGluRs), after which they were named, but in the 16 years since their existence was first revealed, progress in elucidating their biological role has been disappointingly slow. Recently, however, studies from a number of laboratories focusing on the model plant species Arabidopsis thaliana (L.) have thrown new light on the functional properties of some members of the GLR gene family. One important finding has been that plant GLR receptors have a much broader ligand specificity than their mammalian iGluR counterparts, with evidence that some individual GLR receptors can be gated by as many as seven amino acids. These results, together with the ubiquity of their expression throughout the plant, open up the possibility that GLR receptors could have a pervasive role in plants as non-specific amino acid sensors in diverse biological processes. Addressing what one of these roles could be, recent studies examining the wound response and disease susceptibility in GLR knockout mutants have provided evidence that some members of clade 3 of the GLR gene family encode important components of the plant's defence response. Ways in which this family of amino acid receptors might contribute to the plant's ability to respond to an attack from pests and pathogens are discussed. PMID:24991414

  20. Yersinia virulence factors - a sophisticated arsenal for combating host defences

    PubMed Central

    Atkinson, Steve; Williams, Paul

    2016-01-01

    The human pathogens Yersinia pseudotuberculosis and Yersinia enterocolitica cause enterocolitis, while Yersinia pestis is responsible for pneumonic, bubonic, and septicaemic plague. All three share an infection strategy that relies on a virulence factor arsenal to enable them to enter, adhere to, and colonise the host while evading host defences to avoid untimely clearance. Their arsenal includes a number of adhesins that allow the invading pathogens to establish a foothold in the host and to adhere to specific tissues later during infection. When the host innate immune system has been activated, all three pathogens produce a structure analogous to a hypodermic needle. In conjunction with the translocon, which forms a pore in the host membrane, the channel that is formed enables the transfer of six ‘effector’ proteins into the host cell cytoplasm. These proteins mimic host cell proteins but are more efficient than their native counterparts at modifying the host cell cytoskeleton, triggering the host cell suicide response. Such a sophisticated arsenal ensures that yersiniae maintain the upper hand despite the best efforts of the host to counteract the infecting pathogen. PMID:27347390

  1. Efficiency in Israel Defence Forces Dental Labs: assessing the need for privatizing publicly provided services.

    PubMed

    Levy, R; Cohen, M

    1996-01-01

    In the last 10 to 15 years, privatization has been used as a policy instrument to reduce the involvement of the public sector in the provision of a variety of services. The purpose of this paper is to discuss models of privatization in the dental technician market and to report on the findings of an analysis of the functioning and efficiency of such services within the framework of the Israel Defence Forces (IDF). We also develop a method for assessing the quality and efficiency with which such services are produced and assess the need for privatization of the service. Currently, the IDF employs a mixed model of privatization whereby some dental technician services are produced in-house and others are contracted out to the civilian private market. A comparative quantitative analysis of the efficiency, quality, and cost of services indicates that the civilian labs are able to produce prosthetic services at a lower cost per unit of output and at a higher level of quality than are the IDF labs. The highly competitive nature of the industry as well as the relative ease with which the IDF could monitor the quality of service further supports the case for privatization of the entire service. The analysis and method described in this paper can serve as a paradigm for evaluating dental technician services in a variety of settings. PMID:11082751

  2. The use of a hybridization assay for the study of host defences against herpes simplex virus.

    PubMed

    Fluit, A C; van Strijp, J A; Miltenburg, L A; van Kessel, C P; Snippe, H; Verhoef, J

    1989-12-01

    A rapid and simple hybridization assay was developed as an alternative for virus titration for the investigation of host resistance against HSV-1 infections in vitro. The probe which was constructed for this assay was shown to be HSV-1-specific. When a monolayer of fibroblasts was infected for 24 h before hybridization, 15 PFU were detected reliably. A plateau in hybridization levels was found when the multiplicity of infection reached 1. In order to demonstrate the applicability of the probe for the study of host defences against HSV in vitro, fibroblasts were infected with HSV in the presence of different numbers of adherent cells and different concentrations of serum containing high titres of anti-HSV antibodies and complement. After 20 h of incubation, samples were lysed, spotted on Zetaprobe filter paper and hybridized with a 32P-labelled RNA probe. Spots were counted for radioactivity. The radioactivity was taken as a measure of the success of infection. Results showed that at high (10%) concentrations of serum containing high titres of anti-HSV antibodies and complement neutralization plays an important role. At low (1%) concentrations of serum containing high titres of anti-HSV antibodies and complement the phagocytic role of adherent cells becomes the dominant factor in preventing infection of the fibroblasts. However, when the number of infectious particles is increased, the protection provided by adherent cells is overwhelmed.

  3. Lysophosphatidylcholine acts in the constitutive immune defence against American foulbrood in adult honeybees.

    PubMed

    Riessberger-Gallé, Ulrike; Hernández-López, Javier; Rechberger, Gerald; Crailsheim, Karl; Schuehly, Wolfgang

    2016-01-01

    Honeybee (Apis mellifera) imagines are resistant to the Gram-positive bacterium Paenibacillus larvae (P. larvae), causative agent of American foulbrood (AFB), whereas honeybee larvae show susceptibility against this pathogen only during the first 48 h of their life. It is known that midgut homogenate of adult honeybees as well as a homogenate of aged larvae exhibit strong anti-P. larvae activity. A bioactivity-guided LC-HRMS analysis of midgut homogenate resulted in the identification of 1-oleoyl-sn-glycero-3-phosphocholine (LPC) pointing to a yet unknown immune defence in adult honeybees against P. larvae. Antimicrobial activity of LPC was also demonstrated against Melissococcus plutonius, causative agent of European Foulbrood. To demonstrate an AFB-preventive effect of LPC in larvae, artificially reared larvae were supplemented with LPC to evaluate its toxicity and to assess whether, after infection with P. larvae spores, LPC supplementation prevents AFB infection. 10 μg LPC per larva applied for 3 d significantly lowered mortality due to AFB in comparison to controls. A potential delivery route of LPC to the larvae in a colony via nurse bees was assessed through a tracking experiment using fluorescent-labelled LPC. This yet undescribed and non-proteinous defense of honeybees against P. larvae may offer new perspectives for a treatment of AFB without the utilization of classic antibiotics. PMID:27480379

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

    PubMed

    Thorogood, Rose; Davies, Nicholas B

    2016-01-22

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

  5. Revisioning Fordham's 'Defences of the self' in light of modern relational theory and contemporary neuroscience.

    PubMed

    Kalsched, Donald E

    2015-09-01

    This paper explores the evolution of Michael Fordham's ideas concerning 'defences of the self', including his application of this concept to a group of 'difficult' adult patients in his famous 1974 paper by the same name. After tracing the relevance of Fordham's ideas to my own discovery of a 'self-care system' in the psychological material of early trauma patients (Kalsched ), I describe how Fordham's seminal notions might be revisioned in light of contemporary relational theory as well as early attachment theory and affective neuroscience. These revisionings involve an awareness that the severe woundings of early unremembered trauma are not transformable through interpretation but will inevitably be repeated in the transference, leading to mutual 'enactments' between the analytic partners and, hopefully, to a new outcome. A clinical example of one such mutual enactment between the author and his patient is provided. The paper concludes with reflections on the clinical implications of this difficult case and what it means to become a 'real person' to our patients. Finally, Jung's alchemical views on transference are shown to be useful analogies in our understanding of the necessary mutuality in the healing process with these patients.

  6. Cell-wall invertases, key enzymes in the modulation of plant metabolism during defence responses.

    PubMed

    Proels, Reinhard Korbinian; Hückelhoven, Ralph

    2014-10-01

    Most plant-pathogen interactions do not result in pathogenesis because of pre-formed defensive plant barriers or pathogen-triggered activation of effective plant immune responses. The mounting of defence reactions is accompanied by a profound modulation of plant metabolism. Common metabolic changes are the repression of photosynthesis, the increase in heterotrophic metabolism and the synthesis of secondary metabolites. This enhanced metabolic activity is accompanied by the reduced export of sucrose or enhanced import of hexoses at the site of infection, which is mediated by an induced activity of cell-wall invertase (Cw-Inv). Cw-Inv cleaves sucrose, the major transport sugar in plants, irreversibly yielding glucose and fructose, which can be taken up by plant cells via hexose transporters. These hexose sugars not only function in metabolism, but also act as signalling molecules. The picture of Cw-Inv regulation in plant-pathogen interactions has recently been broadened and is discussed in this review. An interesting emerging feature is the link between Cw-Inv and the circadian clock and new modes of Cw-Inv regulation at the post-translational level.

  7. The net benefit of public expenditures on avalanche defence structures in the municipality of Davos, Switzerland

    NASA Astrophysics Data System (ADS)

    Fuchs, S.; McAlpin, M. C.

    2005-04-01

    Avalanches pose a threat to settlements as well as industrial and recreational areas in the Alps. As a counter measure, technical mitigation measures have been implemented since the 19th century, resulting in a raise in value of formerly endangered areas. This increase in value can be considered as a benefit due to prevented damage. This paper compares the total costs and benefits of technical mitigation measures in the municipality of Davos, Switzerland as a basis for evaluating their net social benefit. The benefit of avalanche defence structures is determined using two different approaches. First, the replacement value of buildings protected by mitigation measures is quantified. Second, the number of protected persons is monetarily assessed by means of a human capital approach. The quantified benefit is compared with the present value of cumulative capital expenditures on avalanche mitigation measures. In addition, distributional effects of the public expenditures on technical mitigation measures are discussed based on the average future tax revenues within protected areas. Depending on whether benefits are calculated in terms of protected buildings or protected persons, the results show a large range of cost-benefit ratios. Critical issues of cost-benefit analyses in the context of alpine natural hazards are highlighted, including problems related to the human capital approach and the sensitivity of results to how benefits are calculated. The applicability of cost-benefit analyses for evaluating avalanche mitigation measures is discussed.

  8. Lysophosphatidylcholine acts in the constitutive immune defence against American foulbrood in adult honeybees.

    PubMed

    Riessberger-Gallé, Ulrike; Hernández-López, Javier; Rechberger, Gerald; Crailsheim, Karl; Schuehly, Wolfgang

    2016-01-01

    Honeybee (Apis mellifera) imagines are resistant to the Gram-positive bacterium Paenibacillus larvae (P. larvae), causative agent of American foulbrood (AFB), whereas honeybee larvae show susceptibility against this pathogen only during the first 48 h of their life. It is known that midgut homogenate of adult honeybees as well as a homogenate of aged larvae exhibit strong anti-P. larvae activity. A bioactivity-guided LC-HRMS analysis of midgut homogenate resulted in the identification of 1-oleoyl-sn-glycero-3-phosphocholine (LPC) pointing to a yet unknown immune defence in adult honeybees against P. larvae. Antimicrobial activity of LPC was also demonstrated against Melissococcus plutonius, causative agent of European Foulbrood. To demonstrate an AFB-preventive effect of LPC in larvae, artificially reared larvae were supplemented with LPC to evaluate its toxicity and to assess whether, after infection with P. larvae spores, LPC supplementation prevents AFB infection. 10 μg LPC per larva applied for 3 d significantly lowered mortality due to AFB in comparison to controls. A potential delivery route of LPC to the larvae in a colony via nurse bees was assessed through a tracking experiment using fluorescent-labelled LPC. This yet undescribed and non-proteinous defense of honeybees against P. larvae may offer new perspectives for a treatment of AFB without the utilization of classic antibiotics.

  9. Lysophosphatidylcholine acts in the constitutive immune defence against American foulbrood in adult honeybees

    PubMed Central

    Riessberger-Gallé, Ulrike; Hernández-López, Javier; Rechberger, Gerald; Crailsheim, Karl; Schuehly, Wolfgang

    2016-01-01

    Honeybee (Apis mellifera) imagines are resistant to the Gram-positive bacterium Paenibacillus larvae (P. larvae), causative agent of American foulbrood (AFB), whereas honeybee larvae show susceptibility against this pathogen only during the first 48 h of their life. It is known that midgut homogenate of adult honeybees as well as a homogenate of aged larvae exhibit strong anti-P. larvae activity. A bioactivity-guided LC-HRMS analysis of midgut homogenate resulted in the identification of 1-oleoyl-sn-glycero-3-phosphocholine (LPC) pointing to a yet unknown immune defence in adult honeybees against P. larvae. Antimicrobial activity of LPC was also demonstrated against Melissococcus plutonius, causative agent of European Foulbrood. To demonstrate an AFB-preventive effect of LPC in larvae, artificially reared larvae were supplemented with LPC to evaluate its toxicity and to assess whether, after infection with P. larvae spores, LPC supplementation prevents AFB infection. 10 μg LPC per larva applied for 3 d significantly lowered mortality due to AFB in comparison to controls. A potential delivery route of LPC to the larvae in a colony via nurse bees was assessed through a tracking experiment using fluorescent-labelled LPC. This yet undescribed and non-proteinous defense of honeybees against P. larvae may offer new perspectives for a treatment of AFB without the utilization of classic antibiotics. PMID:27480379

  10. Auditory-based defence against gleaning bats in neotropical katydids (Orthoptera: Tettigoniidae).

    PubMed

    ter Hofstede, Hannah M; Kalko, Elisabeth K V; Fullard, James H

    2010-05-01

    Neotropical katydids (Orthoptera: Tettigoniidae) are preyed on by gleaning bats, which are known to use male calling songs to locate them. At least one katydid species has been reported to stop singing in response to bat echolocation calls. To investigate the relationship between this behavioural defence and ecological and sensory factors, we surveyed calling song characteristics, song cessation in response to the echolocation calls of a sympatric gleaning bat (Trachops cirrhosus), and T-cell responses (an auditory interneuron sensitive to ultrasound) in five katydid species from Panamá. The two katydid species that stopped singing in response to bat calls (Balboa tibialis and Ischnomela gracilis, Pseudophyllinae) also had the highest T-cell spike number and rate in response to these stimuli. The third pseudophylline species (Docidocercus gigliotosi) did not reliably cease singing and had low T-cell spiking activity. Neoconocephalus affinis (Copiphorinae) produced continuous calling song, possibly preventing males from hearing the bat during singing, and did not show a behavioural response despite high T-cell activity in response to bat calls. Steirodon rufolineatum (Phaneropterinae) did not cease singing and differed in T-cell activity compared to the other species. T-cell function might not be conserved in katydids, and evidence for this idea is discussed. PMID:20237786

  11. Integrating resource defence theory with a neural nonapeptide pathway to explain territory-based mating systems

    PubMed Central

    2015-01-01

    The ultimate-level factors that drive the evolution of mating systems have been well studied, but an evolutionarily conserved neural mechanism involved in shaping behaviour and social organization across species has remained elusive. Here, we review studies that have investigated the role of neural arginine vasopressin (AVP), vasotocin (AVT), and their receptor V1a in mediating variation in territorial behaviour. First, we discuss how aggression and territoriality are a function of population density in an inverted-U relationship according to resource defence theory, and how territoriality influences some mating systems. Next, we find that neural AVP, AVT, and V1a expression, especially in one particular neural circuit involving the lateral septum of the forebrain, are associated with territorial behaviour in males of diverse species, most likely due to their role in enhancing social cognition. Then we review studies that examined multiple species and find that neural AVP, AVT, and V1a expression is associated with territory size in mammals and fishes. Because territoriality plays an important role in shaping mating systems in many species, we present the idea that neural AVP, AVT, and V1a expression that is selected to mediate territory size may also influence the evolution of different mating systems. Future research that interprets proximate-level neuro-molecular mechanisms in the context of ultimate-level ecological theory may provide deep insight into the brain-behaviour relationships that underlie the diversity of social organization and mating systems seen across the animal kingdom. PMID:26813803

  12. The effects of dietary thiamin on oxidative damage and antioxidant defence of juvenile fish.

    PubMed

    Li, Xue-Yin; Huang, Hui-Hua; Hu, Kai; Liu, Yang; Jiang, Wei-Dan; Jiang, Jun; Li, Shu-Hong; Feng, Lin; Zhou, Xiao-Qiu

    2014-06-01

    The present study explored the effects of thiamin on antioxidant capacity of juvenile Jian carp (Cyprinus carpio var. Jian). In a 60-day feeding trial, a total of 1,050 juvenile Jian carp (8.20 ± 0.02 g) were fed graded levels of thiamin at 0.25, 0.48, 0.79, 1.06, 1.37, 1.63 and 2.65 mg thiamin kg(-1) diets. The results showed that malondialdehyde and protein carbonyl contents in serum, hepatopancreas, intestine and muscle were significantly decreased with increasing dietary thiamin levels (P < 0.05). Conversely, the anti-superoxide anion capacity and anti-hydroxyl radical capacity in serum, hepatopancreas, intestine and muscle were the lowest in fish fed the thiamin-unsupplemented diet. Meanwhile, the activities of catalase (CAT), glutathione peroxidase, glutathione S-transferase and glutathione reductase, and the contents of glutathione in serum, hepatopancreas, intestine and muscle were enhanced with increasing dietary thiamin levels (P < 0.05). Superoxide dismutase (SOD) activity in serum, hepatopancreas and intestine followed a similar trend as CAT (P < 0.05). However, SOD activity in muscle was not affected by dietary thiamin level (P > 0.05). The results indicated that thiamin could improve antioxidant defence and inhibit lipid peroxidation and protein oxidation of juvenile Jian carp.

  13. The multifunctional artificial reef and its role in the defence of the Mediterranean coast.

    PubMed

    López, I; Tinoco, H; Aragonés, L; García-Barba, J

    2016-04-15

    Multifunctional artificial reefs (MFAR) are being implemented around the world, due to their ability to provide an environment where a sports-economic-recreational use and environmental improvement is implemented, and are also elements of coastal defence. However, a lot of failures have been recorded, possibly due to disregarded local factors in the formulations used, and there is no method that has encompassed all these factors, in order to take them into account in its design. The aim of this paper was to provide the coastal engineer with a method that would be used for the design of such reefs. To do this, the Babilonia beach of Guardamar del Segura, Alicante (Spain), was chosen because it is a fully anthropised area (with houses in the Maritime-Terrestrial Public Domain, marina, channelling and river mouth) with continuous regression, in which all the elements considered in this study, were treated. Based on the performance obtained in studies and projects worldwide, the climatic characteristics, biocenosis, sediment transport, settlements and liquefaction and the evolution of the coastline, were analysed. The multidisciplinary study carried out showed that with the implementation of a MFAR, the problem was reversed. Furthermore, the area was provided with a playful-economic use, and could be used 60% of the time, by surfers whose skill level were low to intermediate, without forgetting that the diversity of the marine ecosystem in the area was increased.

  14. Condom use behaviours and correlates of use in the Botswana Defence Force.

    PubMed

    Tran, Bonnie Robin; Thomas, Anne Goldzier; Ditsela, Mooketsi; Vaida, Florin; Phetogo, Robert; Kelapile, David; Chambers, Christina; Haubrich, Richard; Shaffer, Richard

    2013-11-01

    Preventing HIV infection is a priority for militaries. HIV prevention research is needed to monitor existing programme, identify areas for modification, and develop new interventions. Correct and consistent condom use is highly effective against HIV. However, use among soldiers is lower than ideal. This study describes condom use behaviours and examines correlates of use in the Botswana Defence Force (BDF). Analyses were based on 211 male BDF personnel, aged 18-30, who completed a cross-sectional survey that collected baseline data for an intervention study. Results showed that 51% of participants reported always using condoms, 35% used condoms most times, and 14% used condoms occasionally/never. Condom use varied by partner type and was typically higher with casual partners in comparison to regular partners. After adjustment for age and marital status, factors associated with lower condom use included excessive alcohol use, perception that using condoms reduce sexual pleasure, and having a trusted partner. However, higher levels of HIV knowledge and reports of being circumcised were protective against lower condom use. HIV interventions aimed at increasing condom use in the BDF should address condom perceptions, alcohol abuse, and issues of trust. Innovative ways to increase condom use in this population should also be explored.

  15. Beyond the antipredatory defence: honey bee venom function as a component of social immunity.

    PubMed

    Baracchi, David; Francese, Simona; Turillazzi, Stefano

    2011-11-01

    The honey bee colonies, with the relevant number of immature brood and adults, and stable, high levels of humidity and temperatures of their nests, result in suitable environments for the development of microorganisms including pathogens. In response, honey bees evolved several adaptations to face the increased risks of epidemic diseases. As the antimicrobial venom peptides of Apis mellifera are present both on the cuticle of adult bees and on the nest wax it has been recently suggested that these substances act as a social antiseptic device. Since the use of venom by honey bees in the context of social immunity needs to be more deeply investigated, we extended the study of this potential role of the venom to different species of the genus Apis (A. mellifera, Apis dorsata, Apis cerana and Apis andreniformis) using MALDI-TOF mass spectrometry techniques. In particular we investigated whether (similarly to A. mellifera) the venom is spread over the body cuticle and on the comb wax of these three Asian species. Our results confirm the idea that the venom functions are well beyond the classical stereotype of defence against predators, and suggest that the different nesting biology of these species may be related to the use of the venom in a social immunity context. The presence of antimicrobial peptides on the comb wax of the cavity-dwelling species and on the cuticle of workers of all the studied species represents a good example of "collective immunity" and a component of the "social immunity " respectively.

  16. [Organisation of defence mechanisms in patients suffering from myocardial infarction (author's transl)].

    PubMed

    Hoffmann-Delvaux, C; Mertens, M C

    1977-01-01

    This study was performed to determine the nature and organisation of specific defense mechanism in myocardial infarct patterns as compared to controls. It is also aimed at describing the organisation of these defenses and their relation to anxiety, depression and aggressivity. The samples consist in two populations of 112 male subjects with and without infarct and matched for age and socio-economic status. The EMO questionnaire of G.O. Baehr and M.E. Baehr and the COPE form from the FIRO scales of Schutz were used for psychological evaluation. The results show that the myocardial patients use more turning-against-self and that the other defence mechanisms do not discriminate between the subgroups. Furthermore, the scores for anxiety, depression, inferiority, hostility are similar in both groups. The patients state less sexual problems and use less fantasies than do normal controles. However, they use more somatic concern, but not significantly as compared to controls. This analysis was also concerned with the correlations between these defenses and affects. Furthermore, both subgroups were subdivided in three subsamples according to the score for turning-against self (high, median, low). Turning-against-self is associated with hostility in the patients while this mechanism is associated with a higher susceptibility to dayly events in normal subjects.

  17. Evidence for aggressive mimicry in an adult brood parasitic bird, and generalized defences in its host

    PubMed Central

    Feeney, W. E.; Troscianko, J.; Langmore, N. E.; Spottiswoode, C. N.

    2015-01-01

    Mimicry of a harmless model (aggressive mimicry) is used by egg, chick and fledgling brood parasites that resemble the host's own eggs, chicks and fledglings. However, aggressive mimicry may also evolve in adult brood parasites, to avoid attack from hosts and/or manipulate their perception of parasitism risk. We tested the hypothesis that female cuckoo finches (Anomalospiza imberbis) are aggressive mimics of female Euplectes weavers, such as the harmless, abundant and sympatric southern red bishop (Euplectes orix). We show that female cuckoo finch plumage colour and pattern more closely resembled those of Euplectes weavers (putative models) than Vidua finches (closest relatives); that their tawny-flanked prinia (Prinia subflava) hosts were equally aggressive towards female cuckoo finches and southern red bishops, and more aggressive to both than to their male counterparts; and that prinias were equally likely to reject an egg after seeing a female cuckoo finch or bishop, and more likely to do so than after seeing a male bishop near their nest. This is, to our knowledge, the first quantitative evidence for aggressive mimicry in an adult bird, and suggests that host–parasite coevolution can select for aggressive mimicry by avian brood parasites, and counter-defences by hosts, at all stages of the reproductive cycle. PMID:26063850

  18. Malaria Prevention, Mefloquine Neurotoxicity, Neuropsychiatric Illness, and Risk-Benefit Analysis in the Australian Defence Force.

    PubMed

    McCarthy, Stuart

    2015-01-01

    The Australian Defence Force (ADF) has used mefloquine for malaria chemoprophylaxis since 1990. Mefloquine has been found to be a plausible cause of a chronic central nervous system toxicity syndrome and a confounding factor in the diagnosis of existing neuropsychiatric illnesses prevalent in the ADF such as posttraumatic stress disorder and traumatic brain injury. Overall health risks appear to have been mitigated by restricting the drug's use; however serious risks were realised when significant numbers of ADF personnel were subjected to clinical trials involving the drug. The full extent of the exposure, health impacts for affected individuals, and consequences for ADF health management including mental health are not yet known, but mefloquine may have caused or aggravated neuropsychiatric illness in large numbers of patients who were subsequently misdiagnosed and mistreated or otherwise failed to receive proper care. Findings in relation to chronic mefloquine neurotoxicity were foreseeable, but this eventuality appears not to have been considered during risk-benefit analyses. Thorough analysis by the ADF would have identified this long-term risk as well as other qualitative risk factors. Historical exposure of ADF personnel to mefloquine neurotoxicity now also necessitates ongoing risk monitoring and management in the overall context of broader health policies.

  19. The multifunctional artificial reef and its role in the defence of the Mediterranean coast.

    PubMed

    López, I; Tinoco, H; Aragonés, L; García-Barba, J

    2016-04-15

    Multifunctional artificial reefs (MFAR) are being implemented around the world, due to their ability to provide an environment where a sports-economic-recreational use and environmental improvement is implemented, and are also elements of coastal defence. However, a lot of failures have been recorded, possibly due to disregarded local factors in the formulations used, and there is no method that has encompassed all these factors, in order to take them into account in its design. The aim of this paper was to provide the coastal engineer with a method that would be used for the design of such reefs. To do this, the Babilonia beach of Guardamar del Segura, Alicante (Spain), was chosen because it is a fully anthropised area (with houses in the Maritime-Terrestrial Public Domain, marina, channelling and river mouth) with continuous regression, in which all the elements considered in this study, were treated. Based on the performance obtained in studies and projects worldwide, the climatic characteristics, biocenosis, sediment transport, settlements and liquefaction and the evolution of the coastline, were analysed. The multidisciplinary study carried out showed that with the implementation of a MFAR, the problem was reversed. Furthermore, the area was provided with a playful-economic use, and could be used 60% of the time, by surfers whose skill level were low to intermediate, without forgetting that the diversity of the marine ecosystem in the area was increased. PMID:26851763

  20. Herbivore defence compounds occur in pollen and reduce bumblebee colony fitness.

    PubMed

    Arnold, Sarah E J; Peralta Idrovo, M Eduardo; Lomas Arias, Luis J; Belmain, Steven R; Stevenson, Philip C

    2014-08-01

    Herbivory defence chemicals in plants can affect higher trophic levels such as predators and parasitoids, but the impact on pollinators has been overlooked. We show that defensive plant chemicals can damage pollinator fitness when expressed in pollen. Crop lupins (Lupinus species from Europe and South America) accumulate toxic quinolizidine alkaloids in vegetative tissues, conferring resistance to herbivorous pests such as aphids. We identified the alkaloid lupanine and its derivatives in lupin pollen, and then provided this compound at ecologically-relevant concentrations to queenless microcolonies of bumblebees (Bombus terrestris) in their pollen to determine how foraging on these crops may impact bee colony health and fitness. Fewer males were produced by microcolonies provided with lupanine-treated pollen and they were significantly smaller than controls. This impact on males was not linked to preference as workers willingly fed lupanine-treated pollen to larvae, even though it was deleterious to colony health. Agricultural systems comprising large monocultures of crops bred for herbivore resistance can expose generalist pollinators to deleterious levels of plant compounds, and the broader environmental impacts of crop resistance must thus be considered.

  1. Mechanical defence in seeds to avoid predation by a granivorous ant

    NASA Astrophysics Data System (ADS)

    Oliveras, Jordi; Gómez, Crisanto; Bas, Josep M.; Espadaler, Xavier

    2008-06-01

    Harvester ants have traditionally been considered as seed predators that negatively affect plants. In some cases, however, they can also act as positive seed dispersers. During field observations, we noted that a portion of Psoralea bituminosa seeds that were collected and carried to the nest by the granivorous harvester ant Messor barbarus were discarded intact in refuse piles outside the nest. We analyzed and compared the physical characteristics of size, mass and toughness in P. bituminosa seeds from two different origins: intact seeds found in the ant’s refuse piles and seeds collected directly from the plants. Seeds from refuse piles were similar in width but lighter and tougher than seeds from the plant. Our results point to a mechanical defence based on seed toughness to avoid predation by M. barbarus and suggest that an elevated proportion (~69%) of the seeds produced by P. bituminosa could be too tough to be consumed by this ant. These transported but uneaten seeds could benefit by being moved far from the mother plant and this could act as a selective evolutionary pressure towards tough seeds.

  2. Malaria Prevention, Mefloquine Neurotoxicity, Neuropsychiatric Illness, and Risk-Benefit Analysis in the Australian Defence Force.

    PubMed

    McCarthy, Stuart

    2015-01-01

    The Australian Defence Force (ADF) has used mefloquine for malaria chemoprophylaxis since 1990. Mefloquine has been found to be a plausible cause of a chronic central nervous system toxicity syndrome and a confounding factor in the diagnosis of existing neuropsychiatric illnesses prevalent in the ADF such as posttraumatic stress disorder and traumatic brain injury. Overall health risks appear to have been mitigated by restricting the drug's use; however serious risks were realised when significant numbers of ADF personnel were subjected to clinical trials involving the drug. The full extent of the exposure, health impacts for affected individuals, and consequences for ADF health management including mental health are not yet known, but mefloquine may have caused or aggravated neuropsychiatric illness in large numbers of patients who were subsequently misdiagnosed and mistreated or otherwise failed to receive proper care. Findings in relation to chronic mefloquine neurotoxicity were foreseeable, but this eventuality appears not to have been considered during risk-benefit analyses. Thorough analysis by the ADF would have identified this long-term risk as well as other qualitative risk factors. Historical exposure of ADF personnel to mefloquine neurotoxicity now also necessitates ongoing risk monitoring and management in the overall context of broader health policies. PMID:26793391

  3. The impact of coastal defence structures (tetrapods) on decapod crustaceans in the southern North Sea.

    PubMed

    Wehkamp, Stephanie; Fischer, Philipp

    2013-12-01

    Although the use of coastal defence structures is expected to increase, little is known about the ecological impact of such structures on the natural environment. In particular, the temporal and spatial patterns of communities in association with artificial substrate are still poorly understood. This study examined possible effects of experimental tetrapod fields on the decapod crustacean community in a subtidal hard-bottom area in the southern North Sea. We performed in situ studies in the fields and along transects oriented away from the tetrapod fields. Species composition and abundances were assessed before and after the introduction of the artificial material. The study revealed a significant decrease of smaller, less vagile species (Pisidia longicornis, Pilumnus hirtellus, Galathea squamifera) over the entire study area in the years following the tetrapod introduction. For 2 species, Hyas araneus and Homarus gammarus, the tetrapods appeared to be highly attractive as habitat and shelter because their abundance increased over time. No distinct spatial or temporal effects were observed for mobile predatory crabs, such as Cancer pagurus and Liocarcinus spp. The results of the study demonstrate that possible effects of artificial structures on macro-invertebrates in temperate hard-bottom areas are highly species-specific and depend on the size, lifestyle and ecological requirements of the species. This work highlights the importance of long-term studies. Our findings clearly indicate that more time is needed to distinguish between natural and anthropogenic influences on species distributions. PMID:24041979

  4. Effects of elevated [CO2 ] on maize defence against mycotoxigenic Fusarium verticillioides.

    PubMed

    Vaughan, Martha M; Huffaker, Alisa; Schmelz, Eric A; Dafoe, Nicole J; Christensen, Shawn; Sims, James; Martins, Vitor F; Swerbilow, Jay; Romero, Maritza; Alborn, Hans T; Allen, Leon Hartwell; Teal, Peter E A

    2014-12-01

    Maize is by quantity the most important C4 cereal crop; however, future climate changes are expected to increase maize susceptibility to mycotoxigenic fungal pathogens and reduce productivity. While rising atmospheric [CO2 ] is a driving force behind the warmer temperatures and drought, which aggravate fungal disease and mycotoxin accumulation, our understanding of how elevated [CO2 ] will effect maize defences against such pathogens is limited. Here we report that elevated [CO2 ] increases maize susceptibility to Fusarium verticillioides proliferation, while mycotoxin levels are unaltered. Fumonisin production is not proportional to the increase in F. verticillioides biomass, and the amount of fumonisin produced per unit pathogen is reduced at elevated [CO2 ]. Following F. verticillioides stalk inoculation, the accumulation of sugars, free fatty acids, lipoxygenase (LOX) transcripts, phytohormones and downstream phytoalexins is dampened in maize grown at elevated [CO2 ]. The attenuation of maize 13-LOXs and jasmonic acid production correlates with reduced terpenoid phytoalexins and increased susceptibility. Furthermore, the attenuated induction of 9-LOXs, which have been suggested to stimulate mycotoxin biosynthesis, is consistent with reduced fumonisin per unit fungal biomass at elevated [CO2 ]. Our findings suggest that elevated [CO2 ] will compromise maize LOX-dependent signalling, which will influence the interactions between maize and mycotoxigenic fungi. PMID:24689748

  5. The impact of coastal defence structures (tetrapods) on decapod crustaceans in the southern North Sea.

    PubMed

    Wehkamp, Stephanie; Fischer, Philipp

    2013-12-01

    Although the use of coastal defence structures is expected to increase, little is known about the ecological impact of such structures on the natural environment. In particular, the temporal and spatial patterns of communities in association with artificial substrate are still poorly understood. This study examined possible effects of experimental tetrapod fields on the decapod crustacean community in a subtidal hard-bottom area in the southern North Sea. We performed in situ studies in the fields and along transects oriented away from the tetrapod fields. Species composition and abundances were assessed before and after the introduction of the artificial material. The study revealed a significant decrease of smaller, less vagile species (Pisidia longicornis, Pilumnus hirtellus, Galathea squamifera) over the entire study area in the years following the tetrapod introduction. For 2 species, Hyas araneus and Homarus gammarus, the tetrapods appeared to be highly attractive as habitat and shelter because their abundance increased over time. No distinct spatial or temporal effects were observed for mobile predatory crabs, such as Cancer pagurus and Liocarcinus spp. The results of the study demonstrate that possible effects of artificial structures on macro-invertebrates in temperate hard-bottom areas are highly species-specific and depend on the size, lifestyle and ecological requirements of the species. This work highlights the importance of long-term studies. Our findings clearly indicate that more time is needed to distinguish between natural and anthropogenic influences on species distributions.

  6. The stimulation of immune defence accelerates development in the red flour beetle (Tribolium castaneum).

    PubMed

    Roth, O; Kurtz, J

    2008-11-01

    The timing of the transition between life stages is of key importance for an organism. Depending on the environmental conditions, maturing earlier at a smaller size or maturing later at a larger size can be advantageous for fitness. Exposure to parasites and subsequent immune activation may lead to alterations in development. Immune defence often comes at a cost, such as energy drain towards immune function, which is likely to delay development. On the other hand, animals may react to an anticipated risk of infection with a phenotypically plastic shift in life history, which may more likely lead to accelerated development and earlier maturation. We tested these alternatives in the red flour beetle, Tribolium castaneum. Young larvae were exposed to a non-infectious immune challenge with heat-killed bacteria (either Escherichia coli or Bacillus thuringiensis) and they were followed up for their development, survival, adult size and reproduction. We found that animals that had experienced a bacterial challenge developed into adults earlier than sham-treated beetles, while they did not differ significantly in survival or adult size. Beetles exposed to E. coli produced fewer offspring, while exposure to B. thuringiensis did not affect offspring number. Taken together, our results indicate that T. castaneum is able to speed up its development when facing a risk of infection.

  7. Revisioning Fordham's 'Defences of the self' in light of modern relational theory and contemporary neuroscience.

    PubMed

    Kalsched, Donald E

    2015-09-01

    This paper explores the evolution of Michael Fordham's ideas concerning 'defences of the self', including his application of this concept to a group of 'difficult' adult patients in his famous 1974 paper by the same name. After tracing the relevance of Fordham's ideas to my own discovery of a 'self-care system' in the psychological material of early trauma patients (Kalsched ), I describe how Fordham's seminal notions might be revisioned in light of contemporary relational theory as well as early attachment theory and affective neuroscience. These revisionings involve an awareness that the severe woundings of early unremembered trauma are not transformable through interpretation but will inevitably be repeated in the transference, leading to mutual 'enactments' between the analytic partners and, hopefully, to a new outcome. A clinical example of one such mutual enactment between the author and his patient is provided. The paper concludes with reflections on the clinical implications of this difficult case and what it means to become a 'real person' to our patients. Finally, Jung's alchemical views on transference are shown to be useful analogies in our understanding of the necessary mutuality in the healing process with these patients. PMID:26274848

  8. Technologies for developing an advanced intelligent ATM with self-defence capabilities

    NASA Astrophysics Data System (ADS)

    Sako, Hiroshi

    2010-01-01

    We have developed several technologies for protecting automated teller machines. These technologies are based mainly on pattern recognition and are used to implement various self-defence functions. They include (i) banknote recognition and information retrieval for preventing machines from accepting counterfeit and damaged banknotes and for retrieving information about detected counterfeits from a relational database, (ii) form processing and character recognition for preventing machines from accepting remittance forms without due dates and/or insufficient payment, (iii) person identification to prevent machines from transacting with non-customers, and (iv) object recognition to guard machines against foreign objects such as spy cams that might be surreptitiously attached to them and to protect users against someone attempting to peek at their user information such as their personal identification number. The person identification technology has been implemented in most ATMs in Japan, and field tests have demonstrated that the banknote recognition technology can recognise more then 200 types of banknote from 30 different countries. We are developing an "advanced intelligent ATM" that incorporates all of these technologies.

  9. Malaria Prevention, Mefloquine Neurotoxicity, Neuropsychiatric Illness, and Risk-Benefit Analysis in the Australian Defence Force

    PubMed Central

    McCarthy, Stuart

    2015-01-01

    The Australian Defence Force (ADF) has used mefloquine for malaria chemoprophylaxis since 1990. Mefloquine has been found to be a plausible cause of a chronic central nervous system toxicity syndrome and a confounding factor in the diagnosis of existing neuropsychiatric illnesses prevalent in the ADF such as posttraumatic stress disorder and traumatic brain injury. Overall health risks appear to have been mitigated by restricting the drug's use; however serious risks were realised when significant numbers of ADF personnel were subjected to clinical trials involving the drug. The full extent of the exposure, health impacts for affected individuals, and consequences for ADF health management including mental health are not yet known, but mefloquine may have caused or aggravated neuropsychiatric illness in large numbers of patients who were subsequently misdiagnosed and mistreated or otherwise failed to receive proper care. Findings in relation to chronic mefloquine neurotoxicity were foreseeable, but this eventuality appears not to have been considered during risk-benefit analyses. Thorough analysis by the ADF would have identified this long-term risk as well as other qualitative risk factors. Historical exposure of ADF personnel to mefloquine neurotoxicity now also necessitates ongoing risk monitoring and management in the overall context of broader health policies. PMID:26793391

  10. Possible involvement of maize Rop1 in the defence responses of plants to viral infection.

    PubMed

    Cao, Yanyong; Shi, Yan; Li, Yongqiang; Cheng, Yuqin; Zhou, Tao; Fan, Zaifeng

    2012-09-01

    The expression of host genes can be altered during the process of viral infection. To investigate the viral infection-induced up-regulated gene expression changes of maize at different time intervals post-inoculation with Sugarcane mosaic virus (SCMV), a suppression subtractive hybridization cDNA library was constructed. A total of 454 cDNA clones were identified to be viral infection-induced up-regulated genes. The influence of Rop1 on the infection of maize by SCMV was investigated. The results showed that transient silencing of the ZmRop1 gene through virus-induced gene silencing enhanced the accumulation and systemic infection of SCMV and another potyvirus (Pennisetum mosaic virus) in maize plants, whereas transient over-expression of ZmRop1 in maize protoplasts reduced SCMV accumulation. Furthermore, it was demonstrated that the heterologous expression of ZmRop1 impaired Potato virus X infection in Nicotiana benthamiana plants. These data suggest that ZmRop1 may play a role in plant defence responses to viral infection.

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

    PubMed Central

    Pringle, Elizabeth G.

    2014-01-01

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

  12. Exploring the neutral invertase-oxidative stress defence connection in Arabidopsis thaliana.

    PubMed

    Xiang, Li; Le Roy, Katrien; Bolouri-Moghaddam, Mohammad-Reza; Vanhaecke, Mieke; Lammens, Willem; Rolland, Filip; Van den Ende, Wim

    2011-07-01

    Over the past decades, considerable advances have been made in understanding the crucial role and the regulation of sucrose metabolism in plants. Among the various sucrose-catabolizing enzymes, alkaline/neutral invertases (A/N-Invs) have long remained poorly studied. However, recent findings have demonstrated the presence of A/N-Invs in various organelles in addition to the cytosol, and their importance for plant development and stress tolerance. A cytosolic (At-A/N-InvG, At1g35580) and a mitochondrial (At-A/N-InvA, At1g56560) member of the A/N-Invs have been analysed in more detail in Arabidopsis and it was found that At-A/N-InvA knockout plants show an even more severe growth phenotype than At-A/N-InvG knockout plants. The absence of either A/N-Inv was associated with higher oxidative stress defence gene expression, while transient overexpression of At-A/N-InvA and At-A/N-InvG in leaf mesophyll protoplasts down-regulated the oxidative stress-responsive ascorbate peroxidase 2 (APX2) promoter. Moreover, up-regulation of the APX2 promoter by hydrogen peroxide or abscisic acid could be blocked by adding metabolizable sugars or ascorbate. A hypothetical model is proposed in which both mitochondrial and cytosolic A/N-Invs can generate glucose as a substrate for mitochondria-associated hexokinase, contributing to mitochondrial reactive oxygen species homeostasis.

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

    PubMed Central

    Thorogood, Rose; Davies, Nicholas B.

    2016-01-01

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

  14. Defence Research and Development Canada: Suffield research on nuclear methods for detection of buried bulk explosives

    NASA Astrophysics Data System (ADS)

    McFee, John E.; Faust, Anthony A.

    2011-06-01

    Defence R&D Canada - Suffield has conducted research and development on nuclear methods for detection of bulk explosives since 1994. Initial efforts were directed at confirmation of the presence of bulk explosives in land mines and improvised explosive devices (IEDs). In close collaboration with a few key Canadian companies, methods suitable for vehicle-mounted or fixed position applications and those suitable for person- or small robotportable roles have been studied. Vehicle-mounted systems mainly employ detection of characteristic radiation, whereas person-portable systems use imaging of back scattered radiation intensity distributions. Two key design tenets have been reduction of personnel shielding by the use of teleoperation and custom design of sensors to address the particular problem, rather than adapting an existing sensor to a problem. This is shown in a number of recent research examples. Among vehicle-mounted systems, recent research to improve the thermal neutron analysis (TNA) sensors, which were put into service with the Canadian Forces in 2002, are discussed. Research on fast neutron analysis (FNA) and associated particle imaging (API), which can augment or replace TNA, depending on the application, are described. Monoenergetic gamma ray induced photoneutron spectroscopy is a novel method which has a number of potential advantages and disadvantages over TNA and FNA. Sources, detectors and geometries have been identified and modelling studies have suggested feasibility. Among person-portable systems, research on neutron backscatter imaging and X-ray coded aperture backscatter imaging are discussed.

  15. Respiratory tract lining fluid antioxidants: the first line of defence against gaseous pollutants.

    PubMed

    Kelly, F J; Cotgrove, M; Mudway, I S

    1996-01-01

    All tissues are vulnerable to oxidant damage, but by virtue of its location, anatomy and function, the epithelial surface of the lung is one of the most vulnerable targets in the body. Recent studies have shown that epithelial lining fluid (ELF), a thin layer of fluid which covers the epithelial surface of the respiratory tract, contains an interesting complement of antioxidants, some of which, like glutathione, are present in concentrations much higher than those found in plasma. It is likely that ELF forms the first line of defence against inhaled toxins such as ozone and nitrogen dioxide. By employing an ex vivo exposure system we have demonstrated that when lung lining fluid is in contact with environmentally relevant concentrations of ozone or nitrogen dioxide, there is differential consumption of the water-soluble antioxidants in the order, uric acid > ascorbic acid > glutathione. Given that the majority of ozone and nitrogen dioxide reacts within the ELF compartment, the antioxidant composition of this fluid is critically important in determining an individual's sensitivity to gaseous pollutants.

  16. Assessment of pleiotropic transcriptome perturbations in Arabidopsis engineered for indirect insect defence

    PubMed Central

    2014-01-01

    Background Molecular characterization is an essential step of risk/safety assessment of genetically modified (GM) crops. Holistic approaches for molecular characterization using omics platforms can be used to confirm the intended impact of the genetic engineering, but can also reveal the unintended changes at the omics level as a first assessment of potential risks. The potential of omics platforms for risk assessment of GM crops has rarely been used for this purpose because of the lack of a consensus reference and statistical methods to judge the significance or importance of the pleiotropic changes in GM plants. Here we propose a meta data analysis approach to the analysis of GM plants, by measuring the transcriptome distance to untransformed wild-types. Results In the statistical analysis of the transcriptome distance between GM and wild-type plants, values are compared with naturally occurring transcriptome distances in non-GM counterparts obtained from a database. Using this approach we show that the pleiotropic effect of genes involved in indirect insect defence traits is substantially equivalent to the variation in gene expression occurring naturally in Arabidopsis. Conclusion Transcriptome distance is a useful screening method to obtain insight in the pleiotropic effects of genetic modification. PMID:24947327

  17. The Humber Estuary, Eastern England: Strategic planning of flood defences and habitats.

    PubMed

    Edwards, A M C; Winn, P S J

    2006-01-01

    The Humber Estuary Shoreline Management Plan provides a long-term strategy for investment in sustainable defences to reduce the risk to people and property from flooding in part of Eastern England. In addition to the estuary's economic importance with its ports, industry and the third of a million people living on its floodplain, the Humber is of outstanding value for wildlife and its historic environment. The plan has to meet the needs of these activities and take account of rising sea level. It is based on extensive technical studies and modelling. The realignment of some embankments is being examined so that the creation of intertidal habitat will offset losses from coastal squeeze, increase the stability for some lengths of embankment and reduce extreme high flood levels in the tidal rivers. The 80 ha Paull Holme Strays managed realignment wetland was completed in the summer of 2003 and work is in progress on another at Alkborough. Other such realignment will be developed as part of the implementation of the long term strategy.

  18. The role of trauma scoring in developing trauma clinical governance in the Defence Medical Services

    PubMed Central

    Russell, R. J.; Hodgetts, T. J.; McLeod, J.; Starkey, K.; Mahoney, P.; Harrison, K.; Bell, E.

    2011-01-01

    This paper discusses mathematical models of expressing severity of injury and probability of survival following trauma and their use in establishing clinical governance of a trauma system. There are five sections: (i) Historical overview of scoring systems—anatomical, physiological and combined systems and the advantages and disadvantages of each. (ii) Definitions used in official statistics—definitions of ‘killed in action’ and other categories and the importance of casualty reporting rates and comparison across conflicts and nationalities. (iii) Current scoring systems and clinical governance—clinical governance of the trauma system in the Defence Medical Services (DMS) by using trauma scoring models to analyse injury and clinical patterns. (iv) Unexpected outcomes—unexpected outcomes focus clinical governance tools. Unexpected survivors signify good practice to be promulgated. Unexpected deaths pick up areas of weakness to be addressed. Seventy-five clinically validated unexpected survivors were identified over 2 years during contemporary combat operations. (v) Future developments—can the trauma scoring methods be improved? Trauma scoring systems use linear approaches and have significant weaknesses. Trauma and its treatment is a complex system. Nonlinear methods need to be investigated to determine whether these will produce a better approach to the analysis of the survival from major trauma. PMID:21149354

  19. Neonatal nutrition, adult antioxidant defences and sexual attractiveness in the zebra finch.

    PubMed Central

    Blount, Jonathan D; Metcalfe, Neil B; Arnold, Kathryn E; Surai, Peter F; Devevey, Godefroy L; Monaghan, Pat

    2003-01-01

    Early nutrition has recently been shown to have pervasive, downstream effects on adult life-history parameters including lifespan, but the underlying mechanisms remain poorly understood. Damage to biomolecules caused by oxidants, such as free radicals generated during metabolic processes, is widely recognized as a key contributor to somatic degeneration and the rate of ageing. Lipophilic antioxidants (carotenoids, vitamins A and E) are an important component of vertebrate defences against such damage. By using an avian model, we show here that independent of later nutrition, individuals experiencing a short period of low-quality nutrition during the nestling period had a twofold reduction in plasma levels of these antioxidants at adulthood. We found no effects on adult external morphology or sexual attractiveness: in mate-choice trials females did not discriminate between adult males that had received standard- or lower-quality diet as neonates. Our results suggest low-quality neonatal nutrition resulted in a long-term impairment in the capacity to assimilate dietary antioxidants, thereby setting up a need to trade off the requirement for antioxidant activity against the need to maintain morphological development and sexual attractiveness. Such state-dependent trade-offs could underpin the link between early nutrition and senescence. PMID:12964996

  20. The effects of host defence elicitors on betacyanin accumulation in Amaranthus mangostanus seedlings.

    PubMed

    Cao, Shifeng; Liu, Ting; Jiang, Yueming; He, Shenggen; Harrison, Dion K; Joyce, Daryl C

    2012-10-15

    The effect of elicitors associated with host defence on betacyanin accumulation in Amaranthus mangostanus seedlings was investigated. Under the conditions of the experiments, betacyanin accumulation was generally enhanced by light. Methyl jasmonate (MeJA) treatment increased betacyanin synthesis in a concentration-dependent response. Seedlings treated with ethylene as 5mM Ethephon also had elevated levels of betacyanin. In contrast, salicylic acid (SA) and H(2)O(2) treatments had no influence on betacyanin contents in light or dark. Combined MeJA with Ethephon or H(2)O(2) had an additive effect on betacyanin accumulation in dark-grown seedlings. However, a decline was recorded in light-grown seedlings. Moreover, an antagonistic effect on betacyanin synthesis was found when MeJA and SA were added simultaneously. Our results indicate that betacyanin content in A. mangostanus seedlings can be upregulated by MeJA and ethylene. Both additive and antagonistic effects in regulating betacyanin synthesis in A. mangostanus seedlings were observed between MeJA and other elicitors.

  1. [Arthropodan vectors of human parasites: their pathology and defence reactions (author's transl)].

    PubMed

    Maier, W A

    1976-02-01

    Many infectious diseases of man are transmitted by arthropods. It is not known whether the carriers were primarily susceptible or insusceptible as the cycle first came into existence. Similarly so little is understood, why some arthropods are suitable vectors and other close relatives are not suitable. Only the hypothesis that the agents are original parasites and not at all commensals or symbionts can reasonably explain the evolution of the cycles. It is shown by means of numerous examples how the vector can be damaged by the parasite. Some organs of the vector might become unfunctional, the reproduction rate might be lowered and the vector itself may die. On the other hand the vector has at its disposal defence mechanisms which are according to our present point of view limited to the midgut barrier and the hemolymph reactions. Both components of the system, the vector and the parasite together are capable of change under the influence of the other. For example through the high mortality of the susceptible part of a vector population the resistant and the tolerant individuals will be selected. On the contrary harmful parasites cannot transmit their genetic information when their virulence is so high that the vector will suffer death. Due to this the parasites succumb to a selection pressure and only the careful treatment of the vector is rewarding. Besides this rough pattern of actions and reactions exists also the possibility of developing finer adjustments, with the "molecular mimikry" as a well known example. PMID:769379

  2. Evidence for aggressive mimicry in an adult brood parasitic bird, and generalized defences in its host.

    PubMed

    Feeney, W E; Troscianko, J; Langmore, N E; Spottiswoode, C N

    2015-07-01

    Mimicry of a harmless model (aggressive mimicry) is used by egg, chick and fledgling brood parasites that resemble the host's own eggs, chicks and fledglings. However, aggressive mimicry may also evolve in adult brood parasites, to avoid attack from hosts and/or manipulate their perception of parasitism risk. We tested the hypothesis that female cuckoo finches (Anomalospiza imberbis) are aggressive mimics of female Euplectes weavers, such as the harmless, abundant and sympatric southern red bishop (Euplectes orix). We show that female cuckoo finch plumage colour and pattern more closely resembled those of Euplectes weavers (putative models) than Vidua finches (closest relatives); that their tawny-flanked prinia (Prinia subflava) hosts were equally aggressive towards female cuckoo finches and southern red bishops, and more aggressive to both than to their male counterparts; and that prinias were equally likely to reject an egg after seeing a female cuckoo finch or bishop, and more likely to do so than after seeing a male bishop near their nest. This is, to our knowledge, the first quantitative evidence for aggressive mimicry in an adult bird, and suggests that host-parasite coevolution can select for aggressive mimicry by avian brood parasites, and counter-defences by hosts, at all stages of the reproductive cycle.

  3. Investigating Müllerian mimicry: predator learning and variation in prey defences.

    PubMed

    Ihalainen, E; Lindström, L; Mappes, J

    2007-03-01

    Inexperienced predators are assumed to select for similarity of warning signals in aposematic species (Müllerian mimicry) when learning to avoid them. Recent theoretical work predicts that if co-mimic species have unequal defences, predators attack them according to their average unpalatability and mimicry may not be beneficial for the better defended co-mimic. In this study, we tested in a laboratory environment whether a uniform warning signal is superior to a variable one in promoting predator learning, and simultaneously whether co-mimics are preyed upon according to their average unpalatability. There was an interaction of signal variation and unpalatability but inexperienced birds did not select for signal similarity in artificial prey; when the prey was moderately defended a variable signal was even learnt faster than a uniform one. Due to slow avoidance learning, moderately defended prey had higher mortality than highly defended prey (although this was not straightforward), but mixing high and moderate unpalatability did not increase predation compared with high unpalatability. This does not support the view that predators are sensitive to varying unpalatability. The results suggest that inexperienced predators may neither strongly select for accurate Müllerian mimicry nor affect the benefits of mimicry when the co-mimics are unequally defended.

  4. A novel activator-type ERF of Thinopyrum intermedium, TiERF1, positively regulates defence responses

    PubMed Central

    Liang, HongXia; Lu, Yan; Liu, HongXia; Wang, FengDe; Xin, ZhiYong; Zhang, ZengYan

    2008-01-01

    Thinopyrum intermedium is resistant to many different pathogens. To understand the roles of ethylene response factors (ERFs) in defence responses, the first member of the ERF family in T. intermedium, TiERF1, was characterized and functionally analysed in this study. The TiERF1 gene encodes a putative protein of 292 amino acids, belonging to the B3 subgroup of the ERF transcription factor family. Biochemical assays demonstrated that the TiERF1 protein is capable of binding to the GCC box, a cis-element present in the promoters of pathogenesis-related (PR) genes, and possessing transactivation activity, as well as localizing to the nucleus. The transcript of TiERF1 in T. intermedium is rapidly induced by infection with Rhizoctonia cerealis, Fusarium graminearum, or Blumeria graminis, and ethylene, jasmonic acid, and salicylic acid treatments. More importantly, the ectopic expression of TiERF1 in tobacco activated the transcript of the PR genes of tobacco with a GCC box cis-element, and ACO and ACS genes key to ethylene synthesis, and in turn improved the resistance level to Alternaria alternata and tobacco mosaic virus, as well as causing some phenotypic changes associated with ethylene response in the transgenic tobacco plants. Taken together, TiERF1 protein as an ERF transcription activator positively regulates defence responses via the activation of some defence-related genes. PMID:18611911

  5. Early change in defence mechanisms and coping in short-term dynamic psychotherapy: relations with symptoms and alliance.

    PubMed

    Kramer, Ueli; De Roten, Yves; Michel, Luc; Despland, Jean-Nicholas

    2009-01-01

    Several patient-related variables have already been investigated as predictors of change in psychodynamic psychotherapy. Defensive functioning is one of them. However, few studies have investigated adaptational processes, encompassing defence mechanisms and coping, from an integrative or comparative viewpoint. This study includes 32 patients, mainly diagnosed with adjustment disorder and undergoing time-limited psychodynamic psychotherapy lasting up to 40 sessions, and will focus on early change in defence and coping. Observer-rater methodology was applied to the transcripts of two sessions of the first part of the psychotherapeutic process. It is assumed that the contextual-relational variable of therapeutic alliance intervenes as moderator on change in adaptational processes. Results corroborated the hypothesis, but only for coping, whereas for defences, overall functioning remained stable over the first 20 sessions of psychotherapy. These results are discussed within the framework of disentangling processes underlying adaptation, i.e., related to issues on trait and state aspects, as well as the role of the therapeutic alliance.

  6. Interaction between the moss Physcomitrella patens and Phytophthora: a novel pathosystem for live-cell imaging of subcellular defence.

    PubMed

    Overdijk, Elysa J R; DE Keijzer, Jeroen; DE Groot, Deborah; Schoina, Charikleia; Bouwmeester, Klaas; Ketelaar, Tijs; Govers, Francine

    2016-08-01

    Live-cell imaging of plant-pathogen interactions is often hampered by the tissue complexity and multicell layered nature of the host. Here, we established a novel pathosystem with the moss Physcomitrella patens as host for Phytophthora. The tip-growing protonema cells of this moss are ideal for visualizing interactions with the pathogen over time using high-resolution microscopy. We tested four Phytophthora species for their ability to infect P. patens and showed that P. sojae and P. palmivora were only rarely capable to infect P. patens. In contrast, P. infestans and P. capsici frequently and successfully penetrated moss protonemal cells, showed intracellular hyphal growth and formed sporangia. Next to these successful invasions, many penetration attempts failed. Here the pathogen was blocked by a barrier of cell wall material deposited in papilla-like structures, a defence response that is common in higher plants. Another common response is the upregulation of defence-related genes upon infection and also in moss we observed this upregulation in tissues infected with Phytophthora. For more advanced analyses of the novel pathosystem we developed a special set-up that allowed live-cell imaging of subcellular defence processes by high-resolution microscopy. With this set-up, we revealed that Phytophthora infection of moss induces repositioning of the nucleus, accumulation of cytoplasm and rearrangement of the actin cytoskeleton, but not of microtubules.

  7. Police arrest and self-defence skills: performance under anxiety of officers with and without additional experience in martial arts.

    PubMed

    Renden, Peter G; Landman, Annemarie; Savelsbergh, Geert J P; Oudejans, Raôul R D

    2015-01-01

    We investigated whether officers with additional martial arts training experience performed better in arrest and self-defence scenarios under low and high anxiety and were better able to maintain performance under high anxiety than officers who just rely on regular police training. We were especially interested to find out whether training once a week would already lead to better performance under high anxiety. Officers with additional experience in kickboxing or karate/jiu-jitsu (training several times per week), or krav maga (training once a week) and officers with no additional experience performed several arrest and self-defence skills under low and high anxiety. Results showed that officers with additional experience (also those who trained once a week) performed better under high anxiety than officers with no additional experience. Still, the additional experience did not prevent these participants from performing worse under high anxiety compared to low anxiety. Implications for training are discussed. Practitioner summary: Dutch police officers train their arrest and self-defence skills only four to six hours per year. Our results indicate that doing an additional martial arts training once a week may lead to better performance under anxiety, although it cannot prevent that performance decreases under high anxiety compared to low anxiety.

  8. Application of glycerol as a foliar spray activates the defence response and enhances disease resistance of Theobroma cacao.

    PubMed

    Zhang, Yufan; Smith, Philip; Maximova, Siela N; Guiltinan, Mark J

    2015-01-01

    Previous work has implicated glycerol-3-phosphate (G3P) as a mobile inducer of systemic immunity in plants. We tested the hypothesis that the exogenous application of glycerol as a foliar spray might enhance the disease resistance of Theobroma cacao through the modulation of endogenous G3P levels. We found that exogenous application of glycerol to cacao leaves over a period of 4 days increased the endogenous level of G3P and decreased the level of oleic acid (18:1). Reactive oxygen species (ROS) were produced (a marker of defence activation) and the expression of many pathogenesis-related genes was induced. Notably, the effects of glycerol application on G3P and 18:1 fatty acid content, and gene expression levels, in cacao leaves were dosage dependent. A 100 mm glycerol spray application was sufficient to stimulate the defence response without causing any observable damage, and resulted in a significantly decreased lesion formation by the cacao pathogen Phytophthora capsici; however, a 500 mm glycerol treatment led to chlorosis and cell death. The effects of glycerol treatment on the level of 18:1 and ROS were constrained to the locally treated leaves without affecting distal tissues. The mechanism of the glycerol-mediated defence response in cacao and its potential use as part of a sustainable farming system are discussed.

  9. Fight-flight or freeze-hide? Personality and metabolic phenotype mediate physiological defence responses in flatfish.

    PubMed

    Rupia, Emmanuel J; Binning, Sandra A; Roche, Dominique G; Lu, Weiqun

    2016-07-01

    Survival depends on appropriate behavioural and physiological responses to danger. In addition to active 'fight-flight' defence responses, a passive 'freeze-hide' response is adaptive in some contexts. However, the physiological mechanisms determining which individuals choose a given defence response remain poorly understood. We examined the relationships among personality, metabolic performance and physiological stress responses across an environmental gradient in the olive flounder, Paralichthys olivaceus. We employed four behavioural assays to document the existence of two distinct behavioural types ('bold' and 'shy') in this species. We found consistent metabolic differences between individuals of a given behavioural type across an environmental gradient: shy individuals had overall lower aerobic scope, maximum metabolic rate and standard metabolic rate than bold individuals in both high (25 ppt) and low (3 ppt) salinity. These behavioural and metabolic differences translated into divergent physiological responses during acute stress: shy individuals adopted a passive 'freeze-hide' response by reducing their oxygen consumption rates (akin to shallow breathing) whereas bold individuals adopted an active 'fight-flight' response by increasing their rates of respiration. These distinct defence strategies were repeatable within individuals between salinity treatments. Although it has been suggested theoretically, this is the first empirical evidence that the metabolic response to stressful situations differs between bold and shy individuals. Our results emphasize the importance of incorporating physiological measures to understand the mechanisms driving persistent inter-individual differences in animals.

  10. Phyllosticta musarum Infection-Induced Defences Suppress Anthracnose Disease Caused by Colletotrichum musae in Banana Fruits cv 'Embul'.

    PubMed

    Abayasekara, C L; Adikaram, N K B; Wanigasekara, U W N P; Bandara, B M R

    2013-03-01

    Anthracnose development by Colletotrichum musae was observed to be significantly less in the fruits of the banana cultivar 'Embul' (Mysore, AAB) infected with Phyllosticta musarum than in fruits without such infections. Anthracnose disease originates from quiescent C. musae infections in the immature fruit. P. musarum incites minute, scattered spots, referred to as freckles, in the superficial tissues of immature banana peel which do not expand during maturation or ripening. P. musarum does not appear to have a direct suppressive effect on C. musae as conidia of C. musae germinate on both freckled and non-freckled fruit forming quiescent infections. Our investigations have shown that P. musarum infection induced several defence responses in fruit including the accumulation of five phytoalexins, upregulation of chitinase and β-1,3-glucanase, phenylalanine ammonia lyase (PAL) activity and cell wall lignification. (1)H and (13)C NMR spectral data of one purified phytoalexin compared closely with 4'-hydroxyanigorufone. Some of the P. musarum-induced defences that retained during ripening, restrict C. musae development at the ripe stage. This paper examines the potential of P. musarum-induced defences, in the control of anthracnose, the most destructive postharvest disease in banana. PMID:25288931

  11. Plant defences and the role of epibiosis in mediating within-plant feeding choices of seagrass consumers.

    PubMed

    Vergés, Adriana; Alcoverro, Teresa; Romero, Javier

    2011-06-01

    Within-plant variation in susceptibility to herbivory can significantly influence the ecological and evolutionary consequences of plant-herbivore interactions. Seagrasses are marine angiosperms characterised by substantial intra-individual differences in multiple traits, such as nutrients, chemical and structural defences and epibiotic load, all of which can strongly influence herbivore preferences. We quantified the within-plant feeding choices of the two main consumers of the temperate seagrass Posidonia oceanica--the fish Sarpa salpa and the sea urchin Paracentrotus lividus--and determined the plant traits that explained their foraging strategies. We found strong within-plant heterogeneity in both seagrass susceptibility to herbivory and chemical composition, but different consumers exhibited contrasting feeding choices. S. salpa preferred the most nutritious and chemically defended younger leaves, suggesting a full adaptation to consuming this macrophyte and a greater impact of this herbivore on the plant. In contrast, P. lividus consistently preferred the older leaves covered by epibionts, probably attenuating the relative impact of this consumer and helping to explain the weak effects usually recorded for this echinoid in undisturbed meadows. Artificial diet experiments showed that morphology and fine-scale structural defences were the primary determinant of urchin feeding choices, with nutrient content and chemical defences being of secondary importance. Epibiosis did not strongly influence fish feeding, but it did have a strong 'shared-doom' effect on urchin consumption. This effect was driven by a distinct preference towards a mixed diet that included both host tissues and their epibiotic community. PMID:21053016

  12. Air Pollution.

    ERIC Educational Resources Information Center

    Scorer, Richard S.

    The purpose of this book is to describe the basic mechanisms whereby pollution is transported and diffused in the atmosphere. It is designed to give practitioners an understanding of basic mechanics and physics so they may have a correct basis on which to formulate their decisions related to practical air pollution control problems. Since many…

  13. Air Pollution

    PubMed Central

    Clifton, Marjorie

    1964-01-01

    Dr Marjorie Clifton describes the classification of gaseous and nongaseous constituents of air pollution and then outlines the methods of measuring these. The National Survey embraced 150 towns of all sizes throughout England and Wales and provided data on smoke and sulphur dioxide in relation to climate, topography, industrialization, population density, fuel utilization and urban development. Dr W C Turner discusses the relationship between air pollution and mortality from respiratory conditions, and particularly the incidence of chronic bronchitis. He postulates a theory that such respiratory conditions arise as an allergy to the spores of certain moulds, spore formation being encouraged by the air humidity in Greatv Britain and overcrowded and damp living conditions. He describes the results of a twenty-week study undertaken in 1962-3, showing associations between respiratory disease and levels of air pollution. Dr Stuart Carne undertook a survey in general practice to plot the patterns of respiratory illness in London during the winter of 1962-3. There were two peaks of respiratory illnesses coinciding with the fog at the beginning of December and the freeze-up from the end of December until the beginning of March. PMID:14178955

  14. Viewing AIDS from a glycobiological perspective: potential linkages to the human fetoembryonic defence system hypothesis.

    PubMed

    Clark, G F; Dell, A; Morris, H R; Patankar, M; Oehninger, S; Seppälä, M

    1997-01-01

    proposed model for the protection of the developing human and gametes designated the human fetoembryonic defence system hypothesis. A striking relationship now emerging is that the same unusual carbohydrate sequences associated with these immunosuppressive glycodelins are also specifically expressed on intravascular helminthic parasites, Helicobacter pylori, human tumour cells, and HIV infected T lymphocytes. The information presented in this review suggests that two new corollaries should be added to our recently proposed defence system hypothesis: (i) mimicry or acquisition of glycans that are used in this protective system by pathogens or tumour cells may enable them to either subvert or misdirect the human immune response, thereby greatly increasing their pathogenicity; and (ii) expression of glycoproteins used in this system by normal cells and tissues outside the reproductive system may protect them from immune responses, especially in those cases where major histocompatibility recognition is either absent or minimal. A better understanding of this hypothesis and its corollaries may enable us to address the molecular mechanisms underlying not only AIDS but also a host of other very serious pathological conditions in the human.

  15. Early antioxidative defence responses in the aquatic worms (Limnodrilus sp.) in Porsuk Creek in Eskisehir (Turkey).

    PubMed

    Oztetik, Elif; Cicek, Arzu; Arslan, Naime

    2013-07-01

    Certain oligochaeta specimens have been universally applied as bioindicators to reflect the organic and inorganic pollution in rivers and play a major role in the decomposition of pollutants. The aim of this study was to investigate the water quality in Porsuk Creek in Eskisehir (Turkey) through the specimens from two different species that belong to Limnodrilus genus, using their biomonitoring compatibilities for the accumulated trace element concentrations and to describe the applicability of antioxidative systems as biomarkers of pollution in Tubificinae. Therefore, some parameters that serve as biomarkers for antioxidative defence, total protein, glutathione (GSH) contents and glutathione S-transferase (GST) activities, were determined in Limnodrilus hoffmeisteri and Limnodrilus udekemianus. The study was completed with the chemical analysis of the trace elements from these specimens and also from the water samples. As a conclusion, the observed elevation in GSH levels and GST activities reflect the contribution of oxidative stress in toxicity mechanisms due to the accumulation of trace elements, and the study also suggests a general induction of detoxification metabolisms in the presence of several pollutants in benthic sediment-dwelling worms. According to the average value, the trace element levels for two species are as follows: Fe > Al > Zn > Mn > Pb > Cu > Ni > B > Cd = Cr = Hg. As Porsuk Creek is used for many purposes, such as irrigation, drinking water and fish production, discharges of all types of wastes should be under stringent control to avoid the unwanted health effects to its habitants and to humans. PMID:22514119

  16. Surface microtopographies of tropical sea stars: lack of an efficient physical defence mechanism against fouling.

    PubMed

    Guenther, Jana; De Nys, Rocky

    2007-01-01

    The role of surface topography as a defence against fouling in tropical sea stars was investigated. The sea stars Linckia laevigata, Fromia indica, Cryptasterina pentagona and Archaster typicus are not fouled and have paxillae (modified ossicles with a median vertical pillar) on their aboral surfaces, which varied in diameter, height and distance depending on species and position on the aboral surface, providing unique and complex surface microtopographies for each species. The surfaces of the sea stars L. laevigata, F. indica and A. typicus were moderately wettable, with their mean seawater contact angles, calculated from captive bubble measurements, being 60.1 degrees, 70.3 degrees and 57.3 degrees, respectively. The seawater contact angle of C. pentagona could not be measured. To evaluate the effectiveness of the surface microtopographies in deterring the settlement of fouling organisms, field experiments with resin replicas of the four sea star species were conducted at three sites around Townsville, Australia, for 8 weeks during the dry and wet seasons. The fouling community and total fouling cover did not differ significantly between replicas of L. laevigata, F. indica, C. pentagona, A. typicus and control surfaces at any site during the dry season. Significant differences between fouling communities on the replicas of the sea stars and control surfaces were detected at two sites during the wet season. However, these differences were transitory, and the total fouling cover did not differ significantly between replicas of sea stars and control surfaces at two of the three sites. In contrast to recent literature on the effects of biofouling control by natural surfaces in the marine environment, the surface microtopographies of tropical sea stars alone were not effective in deterring the settlement and growth of fouling organisms.

  17. First line of defence: the role of sloughing in the regulation of cutaneous microbes in frogs.

    PubMed

    Cramp, Rebecca L; McPhee, Rebecca K; Meyer, Edward A; Ohmer, Michel E; Franklin, Craig E

    2014-01-01

    Amphibian populations worldwide are currently experiencing unprecedented declines due to the combined effects of emerging infectious disease and climate change. The skin is the first line of defence in preventing establishment of pathogens and associated infections. Although amphibians undergo regular sloughing of the outer layer of the skin, the potential for regular sloughing to play a role in influencing cutaneous microbial populations and pathogens has been largely overlooked. In the present study, we assessed the effect of skin sloughing on cultivable cutaneous bacterial abundance in the green tree frog (Litoria caerulea). We also examined the effects of temperature and hydric environment on sloughing frequency and microbial re-establishment rates. Our data showed that cultivable cutaneous bacterial abundance was significantly reduced by sloughing events, and frogs kept at 'summer' temperatures (23-33°C) sloughed almost twice as frequently as those maintained at 'winter' temperatures (13-23°C). No effect of hydric environment on sloughing frequency was observed, but we did find that sloughing in L. caerulea appeared to be linked to ambient light cycles. Examination of the effect of sloughing on microbial recolonization indicated that at cool temperatures, an extended intermoult interval allowed microbial abundance to reach higher levels than at warmer 'summer' temperatures (when the intermoult interval was significantly reduced). Our data suggest that sloughing may significantly influence the establishment and/or maintenance of cutaneous bacterial populations (pathogenic, mutualistic and/or commensal) and this, in turn, may be affected by environmental factors, such as ambient light and temperature. These findings are likely to be important for our understanding of the ecology of skin-based pathogens, such as the amphibian chytrid fungus, Batrachochytrium dendrobatidis.

  18. cis-Jasmone induces accumulation of defence compounds in wheat, Triticum aestivum.

    PubMed

    Moraes, Maria C Blassioli; Birkett, Michael A; Gordon-Weeks, Ruth; Smart, Lesley E; Martin, Janet L; Pye, Barry J; Bromilow, Richard; Pickett, John A

    2008-01-01

    Liquid phase extraction (LPE) and vapor phase extraction (VPE) methodologies were used to evaluate the impact of the plant activator, cis-jasmone, on the secondary metabolism of wheat, Triticum aestivum, var. Solstice. LPE allowed the measurement of benzoxazinoids, i.e. 2,4-dihydroxy-7-methoxy-2H-1,4-benzoxazin-3(4H)-one (DIMBOA), 2-hydroxy-7-methoxy-1,4-benzoxazin-3-one (HMBOA) and 6-methoxy-benzoxazolin-2-one (MBOA), and phenolic acids such as trans-p-coumaric acid, syringic acid, p-hydroxybenzoic acid, vanillic acid and cis- and trans-ferulic acid. Using LPE, a significantly higher level of DIMBOA was found in aerial parts and roots of T. aestivum following treatment with cis-jasmone, when compared with untreated plants. Similar results were obtained for phenolic acids, such as trans-ferulic acid and vanillic acid in roots. Using VPE, it was possible to measure levels of 2-hydroxy-7-methoxy-(2H)-1,4-benzoxazin-3(4H)-one (HBOA), benzoxazolin-2(3H)-one (BOA), ferulic acid, syringic acid and coumaric acid. The levels of HBOA in aerial parts and roots were significantly greater in cis-jasmone treated plants compared to untreated plants. cis-Jasmone is known to be a plant activator in terms of production of defence-related volatile semiochemicals that repel aphids and increase the foraging activity of aphid parasitoids. These results show, for the first time, that cis-jasmone also induces selective production of secondary metabolites that are capable of directly reducing development of pests, diseases and weeds.

  19. Effect of 28-homobrassinolide on antioxidant defence system in Raphanus sativus L. under chromium toxicity.

    PubMed

    Sharma, Indu; Pati, Pratap Kumar; Bhardwaj, Renu

    2011-06-01

    Heavy metals have emerged as major environmental contaminants due to rapid industrialization and urbanization. The genotoxic, mutagenic and carcinogenic effects of heavy metal like chromium (Cr) on man, animals and plants have been documented. In plants, accumulation of heavy metals beyond critical levels generates oxidative stress. This stress is generally overcome by antioxidant defence system and stress shielding phytohormones. Thus, the present study has been focused to analyze the effect of one of imperative group of plant hormones, i.e., brassinosteroids (BRs) which have been reported for its protective properties for wide array of environmental stresses. Raphanus sativus L. (Pusa Chetaki) seeds pre-treated with different concentrations of 28-homobrassinolide (28-HBL) were raised under various concentrations of Cr(VI). It was observed that 28-HBL treatment considerably reduced the impact of Cr-stress on seedlings which was evinced upon analysis of morphological and biochemical parameters of 7-days old radish seedlings. The toxic effects of Cr in terms of reduced growth, lowered contents of chlorophyll (Chl), protein, proline; increased malondialdehyde (MDA) content and elevated metal uptake were ameliorated by applications of 28-HBL. Also, the activities of all the antioxidant enzymes except guaiacol peroxidase (POD), increased significantly when subjected to Cr stress in combination with 28-HBL. Overall, seed pre-soaking treatment of 28-HBL at 10(-7) M was most effective in ameliorating Cr stress. The present work emphasizes the protective role of 28-HBL on regulation of antioxidant enzymes and its possible link in amelioration of stress in plants.

  20. First line of defence: the role of sloughing in the regulation of cutaneous microbes in frogs

    PubMed Central

    Cramp, Rebecca L.; McPhee, Rebecca K.; Meyer, Edward A.; Ohmer, Michel E.; Franklin, Craig E.

    2014-01-01

    Amphibian populations worldwide are currently experiencing unprecedented declines due to the combined effects of emerging infectious disease and climate change. The skin is the first line of defence in preventing establishment of pathogens and associated infections. Although amphibians undergo regular sloughing of the outer layer of the skin, the potential for regular sloughing to play a role in influencing cutaneous microbial populations and pathogens has been largely overlooked. In the present study, we assessed the effect of skin sloughing on cultivable cutaneous bacterial abundance in the green tree frog (Litoria caerulea). We also examined the effects of temperature and hydric environment on sloughing frequency and microbial re-establishment rates. Our data showed that cultivable cutaneous bacterial abundance was significantly reduced by sloughing events, and frogs kept at ‘summer’ temperatures (23–33°C) sloughed almost twice as frequently as those maintained at ‘winter’ temperatures (13–23°C). No effect of hydric environment on sloughing frequency was observed, but we did find that sloughing in L. caerulea appeared to be linked to ambient light cycles. Examination of the effect of sloughing on microbial recolonization indicated that at cool temperatures, an extended intermoult interval allowed microbial abundance to reach higher levels than at warmer ‘summer’ temperatures (when the intermoult interval was significantly reduced). Our data suggest that sloughing may significantly influence the establishment and/or maintenance of cutaneous bacterial populations (pathogenic, mutualistic and/or commensal) and this, in turn, may be affected by environmental factors, such as ambient light and temperature. These findings are likely to be important for our understanding of the ecology of skin-based pathogens, such as the amphibian chytrid fungus, Batrachochytrium dendrobatidis. PMID:27293633

  1. Early antioxidative defence responses in the aquatic worms (Limnodrilus sp.) in Porsuk Creek in Eskisehir (Turkey).

    PubMed

    Oztetik, Elif; Cicek, Arzu; Arslan, Naime

    2013-07-01

    Certain oligochaeta specimens have been universally applied as bioindicators to reflect the organic and inorganic pollution in rivers and play a major role in the decomposition of pollutants. The aim of this study was to investigate the water quality in Porsuk Creek in Eskisehir (Turkey) through the specimens from two different species that belong to Limnodrilus genus, using their biomonitoring compatibilities for the accumulated trace element concentrations and to describe the applicability of antioxidative systems as biomarkers of pollution in Tubificinae. Therefore, some parameters that serve as biomarkers for antioxidative defence, total protein, glutathione (GSH) contents and glutathione S-transferase (GST) activities, were determined in Limnodrilus hoffmeisteri and Limnodrilus udekemianus. The study was completed with the chemical analysis of the trace elements from these specimens and also from the water samples. As a conclusion, the observed elevation in GSH levels and GST activities reflect the contribution of oxidative stress in toxicity mechanisms due to the accumulation of trace elements, and the study also suggests a general induction of detoxification metabolisms in the presence of several pollutants in benthic sediment-dwelling worms. According to the average value, the trace element levels for two species are as follows: Fe > Al > Zn > Mn > Pb > Cu > Ni > B > Cd = Cr = Hg. As Porsuk Creek is used for many purposes, such as irrigation, drinking water and fish production, discharges of all types of wastes should be under stringent control to avoid the unwanted health effects to its habitants and to humans.

  2. Endogenous ethanol 'auto-brewery syndrome' as a drunk-driving defence challenge.

    PubMed

    Logan, B K; Jones, A W

    2000-07-01

    The concentration of ethanol in blood, breath or urine constitutes important evidence for prosecuting drunk drivers. For various reasons, the reliability of the results of forensic alcohol analysis are often challenged by the defence. One such argument for acquittal concerns the notion that alcohol could be produced naturally in the body, hence the term 'auto-brewery' syndrome. Although yeasts such as Candida albicans readily produce ethanol in-vitro, whether this happens to any measurable extent in healthy ambulatory subjects is an open question. Over the years, many determinations of endogenous ethanol have been made, and in a few rare instances (Japanese subjects with very serious yeast infections) an abnormally high ethanol concentration (> 80 mg/dl) has been reported. In these atypical individuals, endogenous ethanol appeared to have been produced after they had eaten carbohydrate-rich foods. A particular genetic polymorphism resulting in reduced activity of enzymes involved in hepatic metabolism of ethanol and a negligible first-pass metabolism might explain ethnic differences in rates of endogenous ethanol production and clearance. Other reports of finding abnormally high concentrations of ethanol in body fluids from ostensibly healthy subjects suffer from deficiencies in study design and lack suitable control experiments or used non-specific analytical methods. With reliable gas chromatographic methods of analysis, the concentrations of endogenous ethanol in peripheral venous blood of healthy individuals, as well as those suffering from various metabolic disorders (diabetes, hepatitis, cirrhosis) ranged from 0-0.08 mg/dl. These concentrations are far too low to have any forensic or medical significance. The notion that a motorist's state of intoxication was caused by endogenously produced ethanol lacks merit.

  3. Hexanoic acid protects tomato plants against Botrytis cinerea by priming defence responses and reducing oxidative stress.

    PubMed

    Finiti, Ivan; de la O Leyva, María; Vicedo, Begonya; Gómez-Pastor, Rocío; López-Cruz, Jaime; García-Agustín, Pilar; Real, Maria Dolores; González-Bosch, Carmen

    2014-08-01

    Treatment with the resistance priming inducer hexanoic acid (Hx) protects tomato plants from Botrytis cinerea by activating defence responses. To investigate the molecular mechanisms underlying hexanoic acid-induced resistance (Hx-IR), we compared the expression profiles of three different conditions: Botrytis-infected plants (Inf), Hx-treated plants (Hx) and Hx-treated + infected plants (Hx+Inf). The microarray analysis at 24 h post-inoculation showed that Hx and Hx+Inf plants exhibited the differential expression and priming of many Botrytis-induced genes. Interestingly, we found that the activation by Hx of other genes was not altered by the fungus at this time point. These genes may be considered to be specific targets of the Hx priming effect and may help to elucidate its mechanisms of action. It is noteworthy that, in Hx and Hx+Inf plants, there was up-regulation of proteinase inhibitor genes, DNA-binding factors, enzymes involved in plant hormone signalling and synthesis, and, remarkably, the genes involved in oxidative stress. Given the relevance of the oxidative burst occurring in plant-pathogen interactions, the effect of Hx on this process was studied in depth. We showed by specific staining that reactive oxygen species (ROS) accumulation in Hx+Inf plants was reduced and more restricted around infection sites. In addition, these plants showed higher ratios of reduced to oxidized glutathione and ascorbate, and normal levels of antioxidant activities. The results obtained indicate that Hx protects tomato plants from B. cinerea by regulating and priming Botrytis-specific and non-specific genes, preventing the harmful effects of oxidative stress produced by infection.

  4. Cell adhesion molecules in the pathogenesis of and host defence against microbial infection.

    PubMed Central

    Kerr, J R

    1999-01-01

    Eukaryotic cell adhesion molecules (CAMs) are used by various cells and extracellular molecules in host defence against infection. They are involved in many processes including recognition by circulating phagocytes of a site of inflammation, transmigration through the endothelial barrier, diapedesis through basement membrane and extracellular matrix, and release of effector mechanisms at the infected site. CAMs involved in leucocyte-endothelial cell interaction include the selectins, integrins, and members of the immunoglobulin superfamily. However, CAMs are also used by various microorganisms (protozoa, fungi, bacteria, and viruses) during their pathogenesis. For example, bacteria that utilise CAMs include Mycobacterium tuberculosis, Listeria monocytogenes, Yersinia spp, enteropathogenic Escherichia coli, Shigella spp, Neisseria spp, Bordetella spp, and Borrelia burgdorferi. In addition, CAMs are involved in the pathogenetic effects of the RTX toxins of Pasteurella haemolytica, Actinobacillus actinomycetemcomitans, and the superantigen exotoxins of Staphylococcus aureus and Streptococcus pyogenes. A recurrent and topical theme of potential importance within the bacterial group is the intimate relation between CAMs, bacterial protein receptors, and type III secretion systems. For example, the IpaBCD protein complex is secreted by the type III system of Shigella flexneri and interacts with alpha 5 beta 1 integrin on the eukaryotic cell surface, followed by Rho mediated internalisation; this illustrates the relevance of cellular microbiology. CAMs might prove to be novel therapeutic targets. Comparative genomics has provided the knowledge of shared virulence determinants among diverse bacterial genera, and will continue to deepen our understanding of microbial pathogenesis, particularly in the context of the interaction of prokaryotic and eukaryotic molecules. PMID:10694943

  5. Dysbiotic gut microbiota causes transmissible Crohn's disease-like ileitis independent of failure in antimicrobial defence

    PubMed Central

    Clavel, Thomas; Calasan, Jelena; Lagkouvardos, Ilias; Haange, Sven Bastiaan; Jehmlich, Nico; Basic, Marijana; Dupont, Aline; Hornef, Mathias; von Bergen, Martin; Bleich, André; Haller, Dirk

    2016-01-01

    Objectives Dysbiosis of the intestinal microbiota is associated with Crohn's disease (CD). Functional evidence for a causal role of bacteria in the development of chronic small intestinal inflammation is lacking. Similar to human pathology, TNFdeltaARE mice develop a tumour necrosis factor (TNF)-driven CD-like transmural inflammation with predominant ileal involvement. Design Heterozygous TNFdeltaARE mice and wildtype (WT) littermates were housed under conventional (CONV), specific pathogen-free (SPF) and germ-free (GF) conditions. Microbial communities were analysed by high-throughput 16S ribosomal RNA gene sequencing. Metaproteomes were measured using LC-MS. Temporal and spatial resolution of disease development was followed after antibiotic treatment and transfer of microbial communities into GF mice. Granulocyte infiltration and Paneth cell function was assessed by immunofluorescence and gene expression analysis. Results GF-TNFdeltaARE mice were free of inflammation in the gut and antibiotic treatment of CONV-TNFdeltaARE mice attenuated ileitis but not colitis, demonstrating that disease severity and location are microbiota-dependent. SPF-TNFdeltaARE mice developed distinct ileitis-phenotypes associated with gradual loss of antimicrobial defence. 16S analysis and metaproteomics revealed specific compositional and functional alterations of bacterial communities in inflamed mice. Transplantation of disease-associated but not healthy microbiota transmitted CD-like ileitis to GF-TNFdeltaARE recipients and triggered loss of lysozyme and cryptdin-2 expression. Monoassociation of GF-TNFdeltaARE mice with the human CD-related Escherichia coli LF82 did not induce ileitis. Conclusions We provide clear experimental evidence for the causal role of gut bacterial dysbiosis in the development of chronic ileal inflammation with subsequent failure of Paneth cell function. PMID:25887379

  6. Understanding ontogenetic trajectories of indirect defence: ecological and anatomical constraints in the production of extrafloral nectaries

    PubMed Central

    Villamil, Nora; Márquez-Guzmán, Judith; Boege, Karina

    2013-01-01

    Background and Aims Early ontogenetic stages of myrmecophytic plants are infrequently associated with ants, probably due to constraints on the production of rewards. This study reports for the first time the anatomical and histological limitations constraining the production of extrafloral nectar in young plants, and the implications that the absence of protective ants imposes for plants early during their ontogeny are discussed. Methods Juvenile, pre-reproductive and reproductive plants of Turnera velutina were selected in a natural population and their extrafloral nectaries (EFNs) per leaf were quantified. The anatomical and morphological changes in EFNs during plant ontogeny were studied using scanning electron and light microscopy. Extrafloral nectar volume and sugar concentration were determined as well as the number of patrolling ants. Key Results Juvenile plants were unable to secrete or contain nectar. Pre-reproductive plants secreted and contained nectar drops, but the highest production was achieved at the reproductive stage when the gland is fully cup-shaped and the secretory epidermis duplicates. No ants were observed in juvenile plants, and reproductive individuals received greater ant patrolling than pre-reproductive individuals. The issue of the mechanism of extrafloral nectar release in T. velutina was solved given that we found an anatomical, transcuticular pore that forms a channel-like structure and allows nectar to flow outward from the gland. Conclusions Juvenile stages had no ant protection against herbivores probably due to resource limitation but also due to anatomical constraints. The results are consistent with the growth-differentiation balance hypothesis. As plants age, they increase in size and have larger nutrient-acquiring, photosynthetic and storage capacity, so they are able to invest in defence via specialized organs, such as EFNs. Hence, the more vulnerable juvenile stage should rely on other defensive strategies to reduce the

  7. Antioxidant defence of colostrum and milk in consecutive lactations in sows

    PubMed Central

    2012-01-01

    Background Parturition is supposed to be related to oxidative stress, not only for the mother, but also for the newborn. Moreover, it is not clear whether consecutive pregnancies, parturitions, and lactations are similar to each other in regards to intensity of metabolic processes or differ from each other. The aim of the study was to compare dynamic changes of antioxidative parameters in colostrum and milk of sows taken during 72 h postpartum from animals in consecutive lactations. Activities of glutathione peroxidase (GSH-Px), glutathione transferase (GSH-Tr), and superoxide dismutase (SOD), and amount of vitamin A and C were measured. Healthy pregnant animals were divided into 4 groups according to the assessed lactation: A -1st lactation (n = 10), B - 2nd and 3rd lactation (n = 7), C - 4th and 5th lactation (n = 11), D - 6th - 8th lactation (n = 8). The colostrum was sampled immediately after parturition and after 6, 12, 18 and 36 h while the milk was assessed at 72 h after parturition. Spectrophotometric methods were used for measurements. Results The activity of antioxidative enzymes and the concentration of vitamin A increased with time postpartum. The concentration of vitamin C was the highest between the 18th and 36th h postpartum. Conclusions Dynamic changes in the values of antioxidant parameters measured during the study showed that sows milk provides the highest concentration of antioxidants in the 2nd and 3rd and 4th and 5th lactation giving the best defence against reactive oxygen species to newborns and mammary glands. PMID:22429994

  8. Structural and biochemical characteristics of citrus flowers associated with defence against a fungal pathogen

    PubMed Central

    Marques, João Paulo Rodrigues; Amorim, Lilian; Silva-Junior, Geraldo José; Spósito, Marcel Bellato; Appezzato-da Gloria, Beatriz

    2015-01-01

    The constitutive characters of plants can be structural or biochemical and play an important role in their defence against pathogens. Citrus postbloom fruit drop (PFD) caused by Colletotrichum spp. is one of the most important fungal diseases of citrus. The pathogen infects the flowers, leading to premature fruit drop and reducing citrus production. However, flower buds smaller than 8 mm long are usually not infected by Colletotrichum spp. Thus, this study investigated whether there are constitutive mechanisms in flower buds related to Colletotrichum spp. infection. We studied flower buds that were 2, 3, 4, 8, 12 and 15 mm long and petals, after anthesis, of sweet orange ‘Valência’ using light and scanning electron microscopy and histochemistry. We evaluated the effect of volatile organic compounds (VOCs) in flowers (R-limonene and linalool) on the in vitro growth of Colletotrichum acutatum. We found that the arrangement of the epidermal papillae in the petal primordia, the occurrence of prismatic crystals and the distribution of oil glands are the main differences between buds smaller than 8 mm and buds 8–15 mm long. Osmophores at the tips of petals produced and accumulated phenols, terpenes and lipophilic compounds. Flower buds smaller than 8 mm long have constitutive structural and biochemical barriers to Colletotrichum spp. infection. In addition, this is the first time that osmophores have been reported in citrus. Our study shows that natural terpenes of Citrus flowers inhibit the fungal growth in vitro, highlighting the potential use of terpenes for the chemical control of PFD in citrus. PMID:25535209

  9. Effects of elevated [CO2] on maize defence against mycotoxigenic Fusarium verticillioides

    PubMed Central

    Vaughan, Martha M; Huffaker, Alisa; Schmelz, Eric A; Dafoe, Nicole J; Christensen, Shawn; Sims, James; Martins, Vitor F; Swerbilow, Jay; Romero, Maritza; Alborn, Hans T; Allen, Leon HARTWELL; Teal, Peter EA

    2014-01-01

    Maize is by quantity the most important C4 cereal crop; however, future climate changes are expected to increase maize susceptibility to mycotoxigenic fungal pathogens and reduce productivity. While rising atmospheric [CO2] is a driving force behind the warmer temperatures and drought, which aggravate fungal disease and mycotoxin accumulation, our understanding of how elevated [CO2] will effect maize defences against such pathogens is limited. Here we report that elevated [CO2] increases maize susceptibility to Fusarium verticillioides proliferation, while mycotoxin levels are unaltered. Fumonisin production is not proportional to the increase in F. verticillioides biomass, and the amount of fumonisin produced per unit pathogen is reduced at elevated [CO2]. Following F. verticillioides stalk inoculation, the accumulation of sugars, free fatty acids, lipoxygenase (LOX) transcripts, phytohormones and downstream phytoalexins is dampened in maize grown at elevated [CO2]. The attenuation of maize 13-LOXs and jasmonic acid production correlates with reduced terpenoid phytoalexins and increased susceptibility. Furthermore, the attenuated induction of 9-LOXs, which have been suggested to stimulate mycotoxin biosynthesis, is consistent with reduced fumonisin per unit fungal biomass at elevated [CO2]. Our findings suggest that elevated [CO2] will compromise maize LOX-dependent signalling, which will influence the interactions between maize and mycotoxigenic fungi. Elevated [CO2] increases maize susceptibility to Fusarium verticillioides proliferation but mycotoxin levels are unaltered. The attenuation of maize 13-LOXs and JA production correlates with reduced terpenoid phytoalexins and increased susceptibility. Furthermore, the attenuated induction of 9-LOXs, which have been suggested to stimulate mycotoxin biosynthesis, is consistent with reduced fumonisin per unit fungal biomass at elevated [CO2]. PMID:24689748

  10. The risk to the United Kingdom population of zinc cadmium sulfide dispersion by the Ministry of Defence during the "cold war"

    PubMed Central

    Elliott, P; Phillips, C; Clayton, B; Lachmann, P

    2002-01-01

    Objectives: To estimate exposures to cadmium (Cd) received by the United Kingdom population as a result of the dispersion of zinc Cd sulfide (ZnCdS) by the Ministry of Defence between 1953 and 1964, as a simulator of biological warfare agents. Methods: A retrospective risk assessment study was carried out on the United Kingdom population during the period 1953–64. This determined land and air dispersion of ZnCdS over most of the United Kingdom, inhalation exposure of the United Kingdom population, soil contamination, and risks to personnel operating equipment that dispersed ZnCdS. Results: About 4600 kg ZnCdS were dispersed from aircraft and ships, at times when the prevailing winds would allow large areas of the country to be covered. Cadmium released from 44 long range trials for which data are available, and extrapolated to a total of 76 trials to allow for trials with incomplete information, is about 1.2% of the estimated total release of Cd into the atmosphere over the same period. "Worst case" estimates are 10 µg Cd inhaled over 8 years, equivalent to Cd inhaled in an urban environment in 12–100 days, or from smoking 100 cigarettes. A further 250 kg ZnCdS was dispersed from the land based sites, but significant soil contamination occurred only in limited areas, which were and have remained uninhabited. Of the four personnel involved in the dispersion procedures (who were probably exposed to much higher concentrations of Cd than people on the ground), none are suspected of having related illnesses. Conclusion: Exposure to Cd from dissemination of ZnCdS during the "cold war" should not have resulted in adverse health effects in the United Kingdom population. PMID:11836463

  11. Mammalian antimicrobial proteins and peptides: overview on the RNase A superfamily members involved in innate host defence.

    PubMed

    Boix, Ester; Nogués, M Victòria

    2007-05-01

    The review starts with a general outlook of the main mechanisms of action of antimicrobial proteins and peptides, with the final aim of understanding the biological function of antimicrobial RNases, and identifying the key events that account for their selective properties. Although most antibacterial proteins and peptides do display a wide-range spectrum of action, with a cytotoxic activity against bacteria, fungi, eukaryotic parasites and viruses, we have only focused on their bactericidal activity. We start with a detailed description of the main distinctive structural features of the bacteria target and on the polypeptides, which act as selective host defence weapons.Following, we include an overview of all the current available information on the mammalian RNases which display an antimicrobial activity. There is a wealth of information on the structural, catalytic mechanism and evolutionary relationships of the RNase A superfamily. The bovine pancreatic RNase A (RNase A), the reference member of the mammalian RNase family, has been the main research object of several Nobel laureates in the 60s, 70s and 80s. A potential antimicrobial function was only recently suggested for several members of this family. In fact, the recent evolutionary studies indicate that this protein family may have started off with a host defence function. Antimicrobial RNases constitute an interesting example of proteins involved in the mammalian innate immune defence system. Besides, there is wealth of available information on the mechanism of action of short antimicrobial peptides, but little is known on larger polypeptides, that is, on proteins. Therefore, the identification of the mechanisms of action of antimicrobial RNases would contribute to the understanding of the proteins involved in the innate immunity.

  12. Relic behaviours, coevolution and the retention versus loss of host defences after episodes of avian brood parasitism.

    PubMed

    Rothstein, Stephen I.

    2001-01-01

    Most previous studies of brood parasitism have stressed that host defences, such as egg recognition, are lost in the absence of parasitism. Such losses could result in coevolutionary cycles in which parasites shift away from well-defended hosts only to switch back to them later at a time when these hosts have lost much or all of their defences and the parasite's current hosts have built up effective defences. However, the alternative 'single trajectory' model predicts that parasites rarely switch back to old hosts because ex-hosts retain egg recognition for long periods in the absence of parasitism. If true, egg recognition by the host may be a 'relic behaviour', because in the absence of parasitism its adaptive value is close to neutral. Using artificial nonmimetic eggs, I tested for egg recognition in two populations that are currently unparasitized but that are descended from lineages likely to have been parasitized in the past: the grey catbird, Dumetella carolinensis, on Bermuda and the loggerhead shrike, Lanius ludovicianus, in California. Both of these populations showed long-term retention, ejecting nonmimetic eggs at rates of nearly 100%. Because potential present-day selection pressures, such as conspecific parasitism, do not explain this egg recognition, Bermuda catbirds apparently retain recognition from North American conspecifics that were cowbird hosts before colonizing Bermuda and shrikes retain recognition from Old World congeners that were hosts of cuckoos. Retention is also indicated by passerines in California and the Caribbean that had high rejection rates of nonmimetic eggs before coming into contact with cowbirds. These new data suggest that both the coevolutionary cycles and single trajectory models have importance and that rejection behaviour can have insignificant costs, which is consistent with evolutionary lag explanations for the acceptance of parasitic eggs shown by some cuckoo and many cowbird hosts. Copyright 2001 The Association for

  13. Influence of cow or goat milk consumption on antioxidant defence and lipid peroxidation during chronic iron repletion.

    PubMed

    Díaz-Castro, Javier; Pérez-Sánchez, Luis J; Ramírez López-Frías, Mercedes; López-Aliaga, Inmaculada; Nestares, Teresa; Alférez, María J M; Ojeda, M Luisa; Campos, Margarita S

    2012-07-14

    Despite Fe deficiency and overload having been widely studied, no studies are available about the influence of milk consumption on antioxidant defence and lipid peroxidation during the course of these highly prevalent cases. The objective of the present study was to assess the influence of cow or goat milk-based diets, either with normal or Fe-overload, on antioxidant defence and lipid peroxidation in the liver, brain and erythrocytes of control and anaemic rats after chronic Fe repletion. Weanling male rats were randomly divided into two groups: a control group receiving a normal-Fe diet (45 mg/kg) and an anaemic group receiving a low-Fe diet (5 mg/kg) for 40 d. Control and anaemic rats were fed goat or cow milk-based diets, either with normal Fe or Fe-overload (450 mg/kg), for 30 or 50 d. Fe-deficiency anaemia did not have any effect on antioxidant enzymes or lipid peroxidation in the organs studied. During chronic Fe repletion, superoxide dismutase (SOD) activity was higher in the group of animals fed the cow milk diet compared with the group consuming goat milk. The slight modification of catalase and glutathione peroxidise activities in animals fed the cow milk-based diet reveals that these enzymes are unable to neutralise and scavenge the high generation of free radicals produced. The animals fed the cow milk diet showed higher rates of lipid peroxidation compared with those receiving the goat milk diet, which directly correlated with the increase in SOD activity. It was concluded that goat milk has positive effects on antioxidant defence, even in a situation of Fe overload, limiting lipid peroxidation. PMID:22018161

  14. The Xanthomonas campestris pv. vesicatoria Type-3 Effector XopB Inhibits Plant Defence Responses by Interfering with ROS Production

    PubMed Central

    Priller, Johannes Peter Roman; Reid, Stephen; Konein, Patrick; Dietrich, Petra

    2016-01-01

    The bacterial pathogen Xanthomonas campestris pv. vesicatoria 85–10 (Xcv) translocates about 30 type-3 effector proteins (T3Es) into pepper plants (Capsicum annuum) to suppress plant immune responses. Among them is XopB which interferes with PTI, ETI and sugar-mediated defence responses, but the underlying molecular mechanisms and direct targets are unknown so far. Here, we examined the XopB-mediated suppression of plant defence responses in more detail. Infection of susceptible pepper plants with Xcv lacking xopB resulted in delayed symptom development compared to Xcv wild type infection concomitant with an increased formation of salicylic acid (SA) and expression of pathogenesis-related (PR) genes. Expression of xopB in Arabidopsis thaliana promoted the growth of the virulent Pseudomonas syringae pv. tomato (Pst) DC3000 strain. This was paralleled by a decreased SA-pool and a lower induction of SA-dependent PR gene expression. The expression pattern of early flg22-responsive marker genes indicated that MAPK signalling was not altered in the presence of XopB. However, XopB inhibited the flg22-triggered burst of reactive oxygen species (ROS). Consequently, the transcript accumulation of AtOXI1, a ROS-dependent marker gene, was reduced in xopB-expressing Arabidopsis plants as well as callose deposition. The lower ROS production correlated with a low level of basal and flg22-triggered expression of apoplastic peroxidases and the NADPH oxidase RBOHD. Conversely, deletion of xopB in Xcv caused a higher production of ROS in leaves of susceptible pepper plants. Together our results demonstrate that XopB modulates ROS responses and might thereby compromise plant defence. PMID:27398933

  15. The Xanthomonas campestris pv. vesicatoria Type-3 Effector XopB Inhibits Plant Defence Responses by Interfering with ROS Production.

    PubMed

    Priller, Johannes Peter Roman; Reid, Stephen; Konein, Patrick; Dietrich, Petra; Sonnewald, Sophia

    2016-01-01

    The bacterial pathogen Xanthomonas campestris pv. vesicatoria 85-10 (Xcv) translocates about 30 type-3 effector proteins (T3Es) into pepper plants (Capsicum annuum) to suppress plant immune responses. Among them is XopB which interferes with PTI, ETI and sugar-mediated defence responses, but the underlying molecular mechanisms and direct targets are unknown so far. Here, we examined the XopB-mediated suppression of plant defence responses in more detail. Infection of susceptible pepper plants with Xcv lacking xopB resulted in delayed symptom development compared to Xcv wild type infection concomitant with an increased formation of salicylic acid (SA) and expression of pathogenesis-related (PR) genes. Expression of xopB in Arabidopsis thaliana promoted the growth of the virulent Pseudomonas syringae pv. tomato (Pst) DC3000 strain. This was paralleled by a decreased SA-pool and a lower induction of SA-dependent PR gene expression. The expression pattern of early flg22-responsive marker genes indicated that MAPK signalling was not altered in the presence of XopB. However, XopB inhibited the flg22-triggered burst of reactive oxygen species (ROS). Consequently, the transcript accumulation of AtOXI1, a ROS-dependent marker gene, was reduced in xopB-expressing Arabidopsis plants as well as callose deposition. The lower ROS production correlated with a low level of basal and flg22-triggered expression of apoplastic peroxidases and the NADPH oxidase RBOHD. Conversely, deletion of xopB in Xcv caused a higher production of ROS in leaves of susceptible pepper plants. Together our results demonstrate that XopB modulates ROS responses and might thereby compromise plant defence. PMID:27398933

  16. Are ineffective defence reactions potential target for induced resistance during the compatible wheat-powdery mildew interaction?

    PubMed

    Tayeh, Ch; Randoux, B; Tisserant, B; Khong, G; Jacques, Ph; Reignault, Ph

    2015-11-01

    Powdery mildew caused by Blumeria graminis f.sp. tritici, an obligate aerial biotrophic fungus, would be one of the most damaging wheat (Triticum aestivum) diseases without the extensive use of conventional fungicides. In our study, the expression levels of some basal defence-related genes were investigated during a compatible interaction in order to evaluate wheat reactions to infection, along with the different stages of the infectious process in planta. As fungal conidia initiated their germination and developed appressorial germ tube (AGT), early defence reactions involved the expression of a lipoxygenase (LOX)- and an oxalate oxidase (OXO)-encoding genes, followed by activations of corresponding LOX (EC 1.13.11.12) and OXO (EC 1.2.3.4) activities, respectively. When penetration of AGT took place, up-regulation of chitinases (CHI) and PR1-encoding genes expression occurred along with an increase of CHI (EC 3.2.1.14) activity. Meanwhile, expression of a phenylalanine ammonia-lyase-encoding gene also took place. Up-regulation of a phospholipase C- and lipid transfer proteins-encoding genes expression occurred during the latest stages of infection. Neither the phi glutathione S-transferase (GST)-encoding gene expression nor the GST (EC 2.5.1.13) activity was modified upon wheat infection by powdery mildew. Whether these defence reactions during such a compatible interaction are markers of immunity or susceptibility, and whether they have the ability to contribute to protection upon modulation of their timing and their intensity by resistance inducers are discussed.

  17. Sub-lethal effects of cadmium on the antioxidant defence system of the hydrothermal vent mussel Bathymodiolus azoricus.

    PubMed

    Company, Rui; Serafim, Angela; Cosson, Richard P; Fiala-Médioni, Aline; Camus, Lionel; Serrão-Santos, Ricardo; João Bebianno, Maria

    2010-07-01

    The mussel Bathymodiolus azoricus is one of the most abundant species in the Mid-Atlantic Ridge hydrothermal vents and is continually exposed to the high-temperature venting fluids containing high metal concentrations and enriched in sulphides and methane, which constitute a potential toxic environment for marine species. The aim of this study was to assess the effects of a sub-lethal Cd concentration on the antioxidant defence system of this mussel. B. azoricus were collected at Menez Gwen vent site (37 degrees 51'N, 32 degrees 31'W) and exposed to Cd (50 microg l(-1)) during 24 days, followed by a depuration period of six days. A battery of stress related biomarkers including antioxidant enzymes (superoxide dismutase-SOD, catalase-CAT; glutathione peroxidases-GPx), metallothioneins (MT), lipid peroxidation (LPO) and total oxyradical scavenging capacity (TOSC) were measured in the gills and mantle of B. azoricus. Cd was accumulated linearly during the exposure period in both tissues and no significant elimination occurred after the 6 days of depuration. Antioxidant enzymes activities were significantly higher in the gills. Cyt-SOD, T-GPx and Se-GPx were induced during the experiment but this was also observed in control organisms. Mit-SOD and CAT activities remained relatively unchanged. MT levels increased linearly in the gills of exposed mussels in the first 18 days of exposure. No significant differences were observed between LPO levels of control and exposed mussels. TOSC levels remained unchanged in control and exposed mussels. This suggests that although Cd is being accumulated in the tissues of exposed mussels, MT defence system is enough to detoxify the effect of Cd accumulated in the tissues. Furthermore, other factors besides the presence of Cd are influencing the antioxidant defence system in B. azoricus.

  18. Medical use of cannabis in Australia: "medical necessity" defences under current Australian law and avenues for reform.

    PubMed

    Martin, Charles

    2014-06-01

    The possession of cannabis is an offence in all Australian jurisdictions. No exception is made for medical use under any of the State and Territory Drug Acts, nor the Commonwealth's pharmaceutical regulation scheme. Nevertheless, questions remain about the scope for defences argued on the basis of necessitous medical use. More fundamentally the increasingly favourable light in which the medical use of cannabis is growing to be seen by state and national legislatures overseas raises important questions about the need for reform of Australian drug laws. This article explores those questions. PMID:25087368

  19. [Service for Disaster Medicine of the Ministry of Defence of the Russian Federation at the present stage].

    PubMed

    Belevitin, A B; Korniushko, I G; Iakovlev, S V

    2011-05-01

    The basic documents of the history of service Disaster Medicine in the USSR and the Armed Forces of the country, employed in this branch of medical terminology, classification of emergency situations are presented. The problem of Disaster Medicine Service of the Ministry of Defence of the Russian Federation at the present stage, the levels of its operations and readiness, as well as the structure and objectives of the medical detachment for special purposes are considered. The involvement of service in peacekeeping operations and medical support of local armed conflicts are assessed. PMID:21874877

  20. Air cell

    NASA Astrophysics Data System (ADS)

    Okamura, Okiyoshi; Wakasa, Masayuki; Tamanoi, Yoshihito

    1991-04-01

    The present invention relates to an air cell. This air cell provides a compact light-weight power source for model aircraft permitting them to fly for an extended period so that they may be used for such practical purposes as crop dusting, surveying, and photographing. The cell is comprised of a current collector so disposed between a magnesium, zinc, or aluminum alloy cathode and a petroleum graphite anode that it is in contact with the anode. The anode is formed by adding polytetrafluoroethylene dispersion liquid in a mixture of active carbon and graphite powder, pouring the mixture into a mold and heating it to form the anode. It is fabricated by a plurality of anode sections and is formed with at least one hole so that it can provide a cell which is compact in size and light in weight yet is capable of generating a high output. The anode, the cathode, and a separator are wetted by an electrolytic liquid. The electrolyte is continuously supplied through the life of the cell.

  1. The mobilization of defence mechanisms in the early stages of pea seed germination against Ascochyta pisi.

    PubMed

    Morkunas, Iwona; Formela, Magda; Marczak, Lukasz; Stobiecki, Maciej; Bednarski, Waldemar

    2013-02-01

    Ascochyta pisi is a necrotrophic pathogenic fungus, which mainly survives between seasons through infected seeds. Defence responses of pea embryo axes to A. pisi were investigated in the heterotrophic phase of seed germination and during the transition from the heterotrophic to the autotrophic phase. Germinated pea seeds, both non-inoculated and inoculated with A. pisi, were cultured in perlite for 96 h. Polarographic studies performed on intact embryo axes of germinating pea seeds infected with A. pisi showed a high respiratory intensity in time from 48 to 96 h after inoculation. Forty-eight-hour embryo axes of germinating pea seeds exhibited the highest respiration rate, which in infected axes was maintained at the following time points after inoculation. Moreover, at 72 and 96 h after inoculation, respiratory intensity was by 64% and 73% higher than in the control. Electron paramagnetic resonance analysis revealed a higher concentration of semiquinone free radicals with g values of g (||) = 2.0031 ± 0.0004 and g (⊥) = 2.0048 ± 0.0004 in infected axes than in the control. Generation of superoxide anion radical was also higher in infected axes than in the control but stronger at 72 and 96 h after inoculation. Starting from 72 h after infection, the level of Mn(2+) ions in infected axes decreased in relation to the control. At the same time, the highest activity of superoxide dismutase (EC 1.15.1.1) and catalase (EC 1.11.1.6) was observed in 72-h infected axes. In turn, the activity of peroxidase (EC 1.11.1.7) up to 72 h after infection was lower than in the control. In 48-h infected embryo axes, a very high level of pterocarpan pisatin was observed. Infection of germinating pea seeds with A. pisi restricted mainly the growth of the epicotyl, but did not inhibit the increase in length and fresh weight of root embryo axes versus cultivation time. These results indicate that in pea during the stages of seed germination and early seedling growth, protective

  2. DORIS downstream service: a support to civil defence autorithies in landslides and subsidence risk management

    NASA Astrophysics Data System (ADS)

    Ciampalini, A.; Del Ventisette, C.; Moretti, S.; Manunta, M.; Calò, F.; Paglia, L.; Ardizzone, F.; Guzzetti, F.; Rossi, M.; Bellotti, F.; Colombo, D.; Strozzi, T.; Wegmuller, U.; Mora, O.; Sanches, F.

    2012-04-01

    , additional information on ground displacements through the generation of very long deformation time series, spanning an almost 20 year time interval by properly combining ERS-1, ERS-2 and ENVISAT data. In this work we present the preliminary results relevant to selected European areas (Umbria (Central Italy), Nebrodi (Sicily, Southern Italy), Zermatt (Switzerland), Silesian Coal basin (Poland), Mallorca (Spain) and Budapest basin (Hungary)) affected by ground deformation, highlighting as such EO data and technologies can significantly improve the ability of European Civil Defence authorities to assess and manage the risk induced by natural and man-made hazards.

  3. Macrophages and cytokines in the early defence against herpes simplex virus

    PubMed Central

    Ellermann-Eriksen, Svend

    2005-01-01

    Herpes simplex virus (HSV) type 1 and 2 are old viruses, with a history of evolution shared with humans. Thus, it is generally well-adapted viruses, infecting many of us without doing much harm, and with the capacity to hide in our neurons for life. In rare situations, however, the primary infection becomes generalized or involves the brain. Normally, the primary HSV infection is asymptomatic, and a crucial element in the early restriction of virus replication and thus avoidance of symptoms from the infection is the concerted action of different arms of the innate immune response. An early and light struggle inhibiting some HSV replication will spare the host from the real war against huge amounts of virus later in infection. As far as such a war will jeopardize the life of the host, it will be in both interests, including the virus, to settle the conflict amicably. Some important weapons of the unspecific defence and the early strikes and beginning battle during the first days of a HSV infection are discussed in this review. Generally, macrophages are orchestrating a multitude of anti-herpetic actions during the first hours of the attack. In a first wave of responses, cytokines, primarily type I interferons (IFN) and tumour necrosis factor are produced and exert a direct antiviral effect and activate the macrophages themselves. In the next wave, interleukin (IL)-12 together with the above and other cytokines induce production of IFN-γ in mainly NK cells. Many positive feed-back mechanisms and synergistic interactions intensify these systems and give rise to heavy antiviral weapons such as reactive oxygen species and nitric oxide. This results in the generation of an alliance against the viral enemy. However, these heavy weapons have to be controlled to avoid too much harm to the host. By IL-4 and others, these reactions are hampered, but they are still allowed in foci of HSV replication, thus focusing the activity to only relevant sites. So, no hero does it alone

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

    PubMed

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

    2015-11-01

    Basal stem rot is one of the major diseases of oil palm (Elaies guineensis Jacq.) caused by pathogenic Ganoderma species. Trichoderma and mycorrhizae were proposed to be able to reduce the disease severity. However, their roles in improving oil palm defence system by possibly inducing defence-related genes in the host are not well characterized. To better understand that, transcript profiles of eleven putative defence-related cDNAs in the roots of oil palm inoculated with Trichoderma harzianum T32 and mycorrhizae at different time points were studied. Transcripts encoding putative Bowman-Birk protease inhibitor (EgBBI2) and defensin (EgDFS) increased more than 2 fold in mycorrhizae-treated roots at 6 weeks post inoculation (wpi) compared to those in controls. Transcripts encoding putative dehydrin (EgDHN), glycine-rich RNA binding protein (EgGRRBP), isoflavone reductase (EgIFR), type 2 ribosome inactivating protein (EgT2RIP), and EgDFS increased in the oil palm roots treated with T. harzianum at 6 and/or 12 wpi compared to those in the controls. Some of these genes were also expressed in oil palm roots treated with Ganoderma boninense. This study provides an insight of some defence-related genes induced by Trichoderma and mycorrhizae, and their roles as potential agents to boost the plant defence system. PMID:26322853

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

    PubMed

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

    2015-11-01

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

  6. Testing for the induction of anti-herbivory defences in four Portuguese macroalgae by direct and water-borne cues of grazing amphipods

    NASA Astrophysics Data System (ADS)

    Yun, Hee Young; Cruz, Joana; Treitschke, Michaela; Wahl, Martin; Molis, Markus

    2007-09-01

    Herbivory is a key factor in regulating plant biomass, thereby driving ecosystem performance. Algae have developed multiple adaptations to cope with grazers, including morphological and chemical defences. In a series of experiments we investigated whether several species of macroalgae possess anti-herbivore defences and whether these could be regulated to demand, i.e. grazing events. The potential of direct grazing on defence induction was assessed for two brown ( Dictyopteris membranacea, Fucus vesiculosus) and two red seaweeds ( Gelidium sesquipedale, Sphaerococcus coronopifolius) from São Rafael and Ria Formosa, Portugal. Bioassays conducted with live algal pieces and agar-based food containing lipophilic algal extracts were used to detect changes in palatability after exposure to amphipod attacks (=treatment phase). Fucus vesiculosus was the only species significantly reducing palatability in response to direct amphipod-attacks. This pattern was observed in live F. vesiculosus pieces and agar-based food containing a lipophilic extract, suggesting that lipophilic compounds produced during the treatment phase were responsible for the repulsion of grazers. Water-borne cues of grazed F. vesiculosus as well as non-grazing amphipods also reduced palatability of neighbouring conspecifics. However, this effect was only observed in live tissues of F. vesiculosus. This study is the first to show that amphipods, like isopods, are capable to induce anti-herbivory defences in F. vesiculosus and that a seasonally variable effectiveness of chemical defences might serve as a dynamic control in alga-herbivore interactions.

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

    PubMed

    Zhao, Jian

    2015-04-01

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

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

    PubMed Central

    Zhao, Jian

    2015-01-01

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

  9. Effects of personality on territory defence in communication networks: a playback experiment with radio-tagged great tits.

    PubMed

    Amy, Mathieu; Sprau, Philipp; de Goede, Piet; Naguib, Marc

    2010-12-01

    Individuals often differ consistently in behaviour across time and contexts, and such consistent behavioural differences are commonly described as personality. Personality can play a central role in social behaviour both in dyadic interactions and in social networks. We investigated whether explorative behaviour, as proxy of personality of territorial male great tits (Parus major), predicts their own and their neighbours' territorial responses towards simulated intruders. Several weeks prior to playback, subjects were taken from the wild to test their exploratory behaviour in a standard context in the laboratory. Exploratory behaviour provides a proxy of personality along a slow-fast explorer continuum. Upon release, males were radio-tracked and subsequently exposed to interactive playback simulating a more or a less aggressive territorial intruder (by either overlapping or alternating broadcast songs with the subjects' songs). At the same time, we radio-tracked a neighbour of the playback subject. Male vocal responses during playback and spatial movements after playback varied according to male explorative behaviour and playback treatment. Males with lower exploration scores approached the loudspeaker less, and sang more songs, shorter songs and songs with slower element rates than did males with higher exploration scores. Moreover, neighbour responses were related to the explorative behaviour of the subject receiving the playback but not to their own explorative behaviour. Our overall findings reveal for the first time how personality traits affect resource defence within a communication network providing new insights on the cause of variation in resource defence behaviour.

  10. Male food defence as a by-product of intersexual cooperation in a non-human primate

    PubMed Central

    Arseneau-Robar, T. Jean M.; Müller, Eliane; Taucher, Anouk L.; van Schaik, Carel P.; Willems, Erik P.

    2016-01-01

    Males in a number of group-living species fight in intergroup conflicts to defend access to food resources, a seemingly paradoxical behaviour, given that this resource does not usually limit male fitness directly. We investigated the mechanism(s) driving apparent male food defence in wild vervet monkeys (Chlorocebus aethiops pygerythrus) by testing the effect that female resource access, and female audience size and activity had on the response of focal males during simulated intergroup encounters. Males do not appear to defend food to increase the reproductive success of female group members because their response was not influenced by the presence of provisioning boxes that only females could access. Female audience size was also unimportant, suggesting males do not participate in intergroup encounters to advertise their quality to potential mates. However, focal males almost always followed/supported female group members who initiated an approach towards simulated intruders, supporting that male participation largely functions to gain status as a cooperative group member, and that apparent male food defence in this species arises as a by-product of intersexual cooperation. Our study highlights that considering audience composition and activity can reveal the presence of social incentives and illuminate the evolutionary mechanism(s) promoting joint action in intergroup aggression. PMID:27775042

  11. Opisthobranchia (Mollusca, Gastropoda) – more than just slimy slugs. Shell reduction and its implications on defence and foraging

    PubMed Central

    Wägele, Heike; Klussmann-Kolb, Annette

    2005-01-01

    Background In general shell-less slugs are considered to be slimy animals with a rather dull appearance and a pest to garden plants. But marine slugs usually are beautifully coloured animals belonging to the less-known Opisthobranchia. They are characterized by a large array of interesting biological phenomena, usually related to foraging and/or defence. In this paper our knowledge of shell reduction, correlated with the evolution of different defensive and foraging strategies is reviewed, and new results on histology of different glandular systems are included. Results Based on a phylogeny obtained by morphological and histological data, the parallel reduction of the shell within the different groups is outlined. Major food sources are given and glandular structures are described as possible defensive structures in the external epithelia, and as internal glands. Conclusion According to phylogenetic analyses, the reduction of the shell correlates with the evolution of defensive strategies. Many different kinds of defence structures, like cleptocnides, mantle dermal formations (MDFs), and acid glands, are only present in shell-less slugs. In several cases, it is not clear whether the defensive devices were a prerequisite for the reduction of the shell, or reduction occurred before. Reduction of the shell and acquisition of different defensive structures had an implication on exploration of new food sources and therefore likely enhanced adaptive radiation of several groups. PMID:15715915

  12. The rare sugar d-allose acts as a triggering molecule of rice defence via ROS generation

    PubMed Central

    Akimitsu, Kazuya

    2013-01-01

    Only d-allose, among various rare monosaccharides tested, induced resistance to Xanthomonas oryzae pv. oryzae in susceptible rice leaves with defence responses: reactive oxygen species, lesion mimic formation, and PR-protein gene expression. These responses were suppressed by ascorbic acid or diphenylene iodonium. Transgenic rice plants overexpressing OsrbohC, encoding NADPH oxidase, were enhanced in sensitivity to d-allose. d-Allose-mediated defence responses were suppressed by the presence of a hexokinase inhibitor. 6-Deoxy-d-allose, a structural derivative of d-allose unable to be phosphorylated, did not confer resistance. Transgenic rice plants expressing Escherichia coli AlsK encoding d-allose kinase to increase d-allose 6-phosphate synthesis were more sensitive to d-allose, but E. coli AlsI encoding d-allose 6-phosphate isomerase expression to decrease d-allose 6-phosphate reduced sensitivity. A d-glucose 6-phosphate dehydrogenase-defective mutant was also less sensitive, and OsG6PDH1 complementation restored full sensitivity. These results reveal that a monosaccharide, d-allose, induces rice resistance to X. oryzae pv. oryzae by activating NADPH oxidase through the activity of d-glucose 6-phosphate dehydrogenase, initiated by hexokinase-mediated conversion of d-allose to d-allose 6-phosphate, and treatment with d-allose might prove to be useful for reducing disease development in rice. PMID:24014866

  13. Maternally derived chemical defences are an effective deterrent against some predators of poison frog tadpoles (Oophaga pumilio)

    PubMed Central

    Stynoski, Jennifer L.; Shelton, Georgia; Stynoski, Peter

    2014-01-01

    Parents defend their young in many ways, including provisioning chemical defences. Recent work in a poison frog system offers the first example of an animal that provisions its young with alkaloids after hatching or birth rather than before. But it is not yet known whether maternally derived alkaloids are an effective defence against offspring predators. We identified the predators of Oophaga pumilio tadpoles and conducted laboratory and field choice tests to determine whether predators are deterred by alkaloids in tadpoles. We found that snakes, spiders and beetle larvae are common predators of O. pumilio tadpoles. Snakes were not deterred by alkaloids in tadpoles. However, spiders were less likely to consume mother-fed O. pumilio tadpoles than either alkaloid-free tadpoles of the red-eyed treefrog, Agalychnis callidryas, or alkaloid-free O. pumilio tadpoles that had been hand-fed with A. callidryas eggs. Thus, maternally derived alkaloids reduce the risk of predation for tadpoles, but only against some predators. PMID:24850895

  14. Novel JAZ co-operativity and unexpected JA dynamics underpin Arabidopsis defence responses to Pseudomonas syringae infection.

    PubMed

    de Torres Zabala, Marta; Zhai, Bing; Jayaraman, Siddharth; Eleftheriadou, Garoufalia; Winsbury, Rebecca; Yang, Ron; Truman, William; Tang, Saijung; Smirnoff, Nicholas; Grant, Murray

    2016-02-01

    Pathogens target phytohormone signalling pathways to promote disease. Plants deploy salicylic acid (SA)-mediated defences against biotrophs. Pathogens antagonize SA immunity by activating jasmonate signalling, for example Pseudomonas syringae pv. tomato DC3000 produces coronatine (COR), a jasmonic acid (JA) mimic. This study found unexpected dynamics between SA, JA and COR and co-operation between JAZ jasmonate repressor proteins during DC3000 infection. We used a systems-based approach involving targeted hormone profiling, high-temporal-resolution micro-array analysis, reverse genetics and mRNA-seq. Unexpectedly, foliar JA did not accumulate until late in the infection process and was higher in leaves challenged with COR-deficient P. syringae or in the more resistant JA receptor mutant coi1. JAZ regulation was complex and COR alone was insufficient to sustainably induce JAZs. JAZs contribute to early basal and subsequent secondary plant defence responses. We showed that JAZ5 and JAZ10 specifically co-operate to restrict COR cytotoxicity and pathogen growth through a complex transcriptional reprogramming that does not involve the basic helix-loop-helix transcription factors MYC2 and related MYC3 and MYC4 previously shown to restrict pathogen growth. mRNA-seq predicts compromised SA signalling in a jaz5/10 mutant and rapid suppression of JA-related components on bacterial infection. PMID:26428397

  15. Differential effects of type and quantity of leaf damage on growth, reproduction and defence of lima bean (Phaseolus lunatus L.).

    PubMed

    Blue, E; Kay, J; Younginger, B S; Ballhorn, D J

    2015-05-01

    Folivores are major plant antagonists in most terrestrial ecosystems. However, the quantitative effects of leaf area loss on multiple interacting plant traits are still little understood. We sought to contribute to filling this lack of understanding by applying different types of leaf area removal (complete leaflets versus leaflet parts) and degrees of leaf damage (0, 33 and 66%) to lima bean (Phaseolus lunatus) plants. We quantified various growth and fitness parameters including above- and belowground biomass as well as the production of reproductive structures (fruits, seeds). In addition, we measured plant cyanogenic potential (HCNp; direct chemical defence) and production of extrafloral nectar (EFN; indirect defence). Leaf damage reduced above- and belowground biomass production in general, but neither variation in quantity nor type of damage resulted in different biomass. Similarly, the number of fruits and seeds was significantly reduced in all damaged plants without significant differences between treatment groups. Seed mass, however, was affected by both type and quantity of leaf damage. Leaf area loss had no impact on HCNp, whereas production of EFN decreased with increasing damage. While EFN production was quantitatively affected by leaf area removal, the type of damage had no effect. Our study provides a thorough analysis of the quantitative and qualitative effects of defoliation on multiple productivity-related and defensive plant traits and shows strong differences in plant response depending on trait. Quantifying such plant responses is vital to our understanding of the impact of herbivory on plant fitness and productivity in natural and agricultural ecosystems.

  16. 14-3-3 gene family in hybrid poplar and its involvement in tree defence against pathogens.

    PubMed

    Lapointe, G; Luckevich, M D; Cloutier, M; Séguin, A

    2001-06-01

    In ongoing investigations of the role of the signal transduction pathway in tree-pathogen interactions, four complete and two partial 14-3-3 cDNAs have been isolated which are members of a gene family. Comparisons of DNA sequences reveal a high degree of identity among the cDNAs, and, in some cases, higher than 75% sequence similarity with previously published sequences. Sequence analysis at the amino acid level uncovered potential phosphorylation sites, some of which were identical among the proteins, and some of which varied. Treatment of trees with chitosan, jasmonates or by wounding of leaves, caused increases in the levels of 14-3-3 mRNA transcripts. Since jasmonates and chitosan are signal transducers of defence reactions in plants, these results suggest a possible role for 14-3-3 proteins in the pathogen defence response of deciduous trees. Effects of elicitors on transcription of the pal gene were also monitored. Pal is a well-characterized, pathogen response-related gene.

  17. The influence of space and time on the evolution of altruistic defence: the case of ant slave rebellion.

    PubMed

    Metzler, D; Jordan, F; Pamminger, T; Foitzik, S

    2016-05-01

    How can antiparasite defence traits evolve even if they do not directly benefit their carriers? An example of such an indirect defence is rebellion of enslaved Temnothorax longispinosus ant workers against their social parasite Temnothorax americanus, a slavemaking ant. Ant slaves have been observed to kill their oppressors' offspring, a behaviour from which the sterile slaves cannot profit directly. Parasite brood killing could, however, reduce raiding pressure on related host colonies nearby. We analyse with extensive computer simulations for the Temnothorax slavemaker system under what conditions a hypothetical rebel allele could invade a host population, and in particular, how host-parasite dynamics and population structure influence the rebel allele's success. Exploring a wide range of model parameters, we only found a small number of parameter combinations for which kin selection or multilevel selection could allow a slave rebellion allele to spread in the host population. Furthermore, we did not detect any cases in which the reduction of raiding pressure in the close vicinity of the slavemaker nest would substantially contribute to the inclusive fitness of rebels. This suggests that slave rebellion is not costly and perhaps a side-effect of some other beneficial trait. In some of our simulations, however, even a costly rebellion allele could spread in the population. This was possible when host-parasite interactions led to a metapopulation dynamic with frequent local extinctions and recolonizations of demes by the offspring of few immigrants.

  18. Effect of temperature acclimation on the liver antioxidant defence system of the Antarctic nototheniids Notothenia coriiceps and Notothenia rossii.

    PubMed

    Machado, Cintia; Zaleski, Tania; Rodrigues, Edson; Carvalho, Cleoni Dos Santos; Cadena, Silvia Maria Suter Correia; Gozzi, Gustavo Jabor; Krebsbach, Priscila; Rios, Flávia Sant'Anna; Donatti, Lucélia

    2014-01-01

    The aim of this study was to determine whether endemic Antarctic nototheniid fish are able to adjust their liver antioxidant defence system in response to the temperature increase. The activity of the superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione-S-transferase (GST) and glutathione reductase (GR) enzymes as well as the content of non-enzymatic oxidative stress markers such as reduced glutathione (GSH), lipid peroxidation (LPO) and protein carbonyl (PC) were measured in the liver of two Antarctic fish species, Notothenia rossii and Notothenia coriiceps after 1, 3 and 6days of exposure to temperatures of 0°C and 8°C. The GST activity showed a downregulation in N. rossii after 6days of exposure to the increased temperature. The activity profiles of GST and GR in N. rossii and of GPx in N. coriiceps also changed as a consequence of heating to 8°C. The GSH content increased by heating to 8°C after 3days in N. coriiceps and after 6days in N. rossii. The content of malondialdehyde (MDA), a LPO marker, showed a negative modulation by the heating to 8°C in N. rossii after 3days of exposure to temperatures. Present results show that heating to 8°C influenced the levels and profiles of the antioxidant enzymes and defences over time in the nototheniid fish N. rossii and N. coriiceps. PMID:24607634

  19. The influence of space and time on the evolution of altruistic defence: the case of ant slave rebellion.

    PubMed

    Metzler, D; Jordan, F; Pamminger, T; Foitzik, S

    2016-05-01

    How can antiparasite defence traits evolve even if they do not directly benefit their carriers? An example of such an indirect defence is rebellion of enslaved Temnothorax longispinosus ant workers against their social parasite Temnothorax americanus, a slavemaking ant. Ant slaves have been observed to kill their oppressors' offspring, a behaviour from which the sterile slaves cannot profit directly. Parasite brood killing could, however, reduce raiding pressure on related host colonies nearby. We analyse with extensive computer simulations for the Temnothorax slavemaker system under what conditions a hypothetical rebel allele could invade a host population, and in particular, how host-parasite dynamics and population structure influence the rebel allele's success. Exploring a wide range of model parameters, we only found a small number of parameter combinations for which kin selection or multilevel selection could allow a slave rebellion allele to spread in the host population. Furthermore, we did not detect any cases in which the reduction of raiding pressure in the close vicinity of the slavemaker nest would substantially contribute to the inclusive fitness of rebels. This suggests that slave rebellion is not costly and perhaps a side-effect of some other beneficial trait. In some of our simulations, however, even a costly rebellion allele could spread in the population. This was possible when host-parasite interactions led to a metapopulation dynamic with frequent local extinctions and recolonizations of demes by the offspring of few immigrants. PMID:26873305

  20. Do Leaf Cutting Ants Cut Undetected? Testing the Effect of Ant-Induced Plant Defences on Foraging Decisions in Atta colombica

    PubMed Central

    Kost, Christian; Tremmel, Martin; Wirth, Rainer

    2011-01-01

    Leaf-cutting ants (LCAs) are polyphagous, yet highly selective herbivores. The factors that govern their selection of food plants, however, remain poorly understood. We hypothesized that the induction of anti-herbivore defences by attacked food plants, which are toxic to either ants or their mutualistic fungus, should significantly affect the ants' foraging behaviour. To test this “induced defence hypothesis,” we used lima bean (Phaseolus lunatus), a plant that emits many volatile organic compounds (VOCs) upon herbivore attack with known anti-fungal or ant-repellent effects. Our results provide three important insights into the foraging ecology of LCAs. First, leaf-cutting by Atta ants can induce plant defences: Lima bean plants that were repeatedly exposed to foraging workers of Atta colombica over a period of three days emitted significantly more VOCs than undamaged control plants. Second, the level to which a plant has induced its anti-herbivore defences can affect the LCAs' foraging behaviour: In dual choice bioassays, foragers discriminated control plants from plants that have been damaged mechanically or by LCAs 24 h ago. In contrast, strong induction levels of plants after treatment with the plant hormone jasmonic acid or three days of LCA feeding strongly repelled LCA foragers relative to undamaged control plants. Third, the LCA-specific mode of damaging leaves allows them to remove larger quantities of leaf material before being recognized by the plant: While leaf loss of approximately 15% due to a chewing herbivore (coccinelid beetle) was sufficient to significantly increase VOC emission levels after 24 h, the removal of even 20% of a plant's leaf area within 20 min by LCAs did not affect its VOC emission rate after 24 h. Taken together, our results support the “induced defence hypothesis” and provide first empirical evidence that the foraging behaviour of LCAs is affected by the induction of plant defence responses. PMID:21799831