233 research outputs found

    Effect of grazing management on the maintenance of white clover

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    End of Project ReportTeagasc acknowledges the support of the European Union Structural Funds (EAGGF) and the European Union DGX11 (Science and Technology for Development Programme, Sub-programme Life Sciences and Technologies for Developing Countries (ST3) in Contract TS3* CT93 0202) in the financing of this project.The objectives of the project were to compare different cultivar types and methods to establish and maintain them in reseeded and permanent pastures as a basis for efficient low cost sheep production. In Ireland only 3% of pastures are reseeded annually and permanent pastures rarely contain more than 5% white clover. Improved clover content offers benefits of higher lamb growth rate and reduced fertiliser N use. Comparisons under cutting conditions provided no basis for replacement of Grasslands Huia by the new cultivar Aberherald. Grasslands Huia established successfully following direct reseeding and rotational grazing by sheep. It established more quickly than Kentish and gave higher yield only in the first year. A mixture of small and medium size white clovers should be sown for sheep grazing. Increasing seeding rate from 2 to 4 kg per ha increased pasture clover content only in the first year. Grasslands Huia persisted quite well for up to 5 years under rotational sheep grazing. It also survived under continuous grazing but leaf size was reduced. Rotational grazing management with sheep increased the clover content of permanent pasture from under 2% to 4% over 2 years. Highest clover yields were achieved with rest intervals of 20 to 28 days. Simulated mixed sheep and cattle rotational grazing on permanent pasture resulted in intermediate (10 to 12%) clover dry matter contributions to total dry matter compared with cattle (15 to 18%) and sheep (5 to 8%). Lamb growth rate was about 35% higher when the clover content of the sward was increased from very low to about 35%.European Unio

    National Soils Database

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    End of project reportThe objectives of the National Soils Database project were fourfold. The first was to generate a national database of soil geochemistry to complete the work that commenced with a survey of the South East of Ireland carried out in 1995 and 1996 by Teagasc (McGrath and McCormack, 1999). Secondly, to produce point and interpolated spatial distribution maps of major, minor and trace elements and to interpret these with respect to underlying parent material, glacial geology, land use and possible anthropogenic effects. A third objective was to investigate the microbial community structure in a range of soil types to determine the relationship between soil microbiology and chemistry. The final objective was to establish a National Soils Archive

    Doxycycline Prophylaxis for Bacterial Sexually Transmitted Infections

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    Bacterial sexually transmitted infections (STIs) have been increasing over the past 2 decades in gay, bisexual, and other men who have sex with men. With the widespread use of early human immunodeficiency virus (HIV) treatment, which virtually eliminates transmission risk, and the availability of HIV pre-exposure prophylaxis, there have been attitudinal changes regarding HIV infection with resultant increases in sexual contact and declines in condom use. Doxycycline is used for primary prophylaxis in a number of infectious diseases. We conducted a state-of-the-art review to examine the current state of research, knowledge gaps, and challenges around the use of doxycycline prophylaxis to prevent syphilis and other STIs. International academic and government experts met in March 2019 to frame the initial inquiry, which was supplemented by focused literature searches. Two small short-term randomized controlled trials examining doxycycline prophylaxis found high efficacy. Five additional clinical studies are underway or in development. Studies differed in design, population, outcomes, and safety measures. Doxycycline prophylaxis for bacterial STIs shows promise. Better and more robust data are needed on efficacy; target population; community acceptability; behavioral risk compensation; doxycycline dose, regimen, and formulation; long-term safety; antimicrobial resistance; cost-effectiveness; and risk–benefit

    S-Nitrosoglutathione reductase (GSNOR) mediates the biosynthesis of jasmonic acid and ethylene induced by feeding of the insect herbivore Manduca sexta and is important for jasmonate-elicited responses in Nicotiana attenuata

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    S-nitrosoglutathione reductase (GSNOR) reduces the nitric oxide (NO) adduct S-nitrosoglutathione (GSNO), an essential reservoir for NO bioactivity. In plants, GSNOR has been found to be important in resistance to bacterial and fungal pathogens, but whether it is also involved in plant–herbivore interactions was not known. Using a virus-induced gene silencing (VIGS) system, the activity of GSNOR in a wild tobacco species, Nicotiana attenuata, was knocked down and the function of GSNOR in defence against the insect herbivore Manduca sexta was examined. Silencing GSNOR decreased the herbivory-induced accumulation of jasmonic acid (JA) and ethylene, two important phytohormones regulating plant defence levels, without compromising the activity of two mitogen-activated protein kinases (MAPKs), salicylic acid-induced protein kinase (SIPK) and wound-induced protein kinase (WIPK). Decreased activity of trypsin proteinase inhibitors (TPIs) were detected in GSNOR-silenced plants after simulated M. sexta feeding and bioassays indicated that GSNOR-silenced plants have elevated susceptibility to M. sexta attack. Furthermore, GSNOR is required for methyl jasmonate (MeJA)-induced accumulation of defence-related secondary metabolites (TPI, caffeoylputrescine, and diterpene glycosides) but is not needed for the transcriptional regulation of JAZ3 (jasmonate ZIM-domain 3) and TD (threonine deaminase), indicating that GSNOR mediates certain but not all jasmonate-inducible responses. This work highlights the important role of GSNOR in plant resistance to herbivory and jasmonate signalling and suggests the potential involvement of NO in plant–herbivore interactions. Our data also suggest that GSNOR could be a target of genetic modification for improving crop resistance to herbivores

    Nitric Oxide Enhances Desiccation Tolerance of Recalcitrant Antiaris toxicaria Seeds via Protein S-Nitrosylation and Carbonylation

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    The viability of recalcitrant seeds is lost following stress from either drying or freezing. Reactive oxygen species (ROS) resulting from uncontrolled metabolic activity are likely responsible for seed sensitivity to drying. Nitric oxide (NO) and the ascorbate-glutathione cycle can be used for the detoxification of ROS, but their roles in the seed response to desiccation remain poorly understood. Here, we report that desiccation induces rapid accumulation of H2O2, which blocks recalcitrant Antiaris toxicaria seed germination; however, pretreatment with NO increases the activity of antioxidant ascorbate-glutathione pathway enzymes and metabolites, diminishes H2O2 production and assuages the inhibitory effects of desiccation on seed germination. Desiccation increases the protein carbonylation levels and reduces protein S-nitrosylation of these antioxidant enzymes; these effects can be reversed with NO treatment. Antioxidant protein S-nitrosylation levels can be further increased by the application of S-nitrosoglutathione reductase inhibitors, which further enhances NO-induced seed germination rates after desiccation and reduces desiccation-induced H2O2 accumulation. These findings suggest that NO reinforces recalcitrant seed desiccation tolerance by regulating antioxidant enzyme activities to stabilize H2O2 accumulation at an appropriate concentration. During this process, protein carbonylation and S-nitrosylation patterns are used as a specific molecular switch to control antioxidant enzyme activities

    A Stochastic Model of Latently Infected Cell Reactivation and Viral Blip Generation in Treated HIV Patients

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    Motivated by viral persistence in HIV+ patients on long-term anti-retroviral treatment (ART), we present a stochastic model of HIV viral dynamics in the blood stream. We consider the hypothesis that the residual viremia in patients on ART can be explained principally by the activation of cells latently infected by HIV before the initiation of ART and that viral blips (clinically-observed short periods of detectable viral load) represent large deviations from the mean. We model the system as a continuous-time, multi-type branching process. Deriving equations for the probability generating function we use a novel numerical approach to extract the probability distributions for latent reservoir sizes and viral loads. We find that latent reservoir extinction-time distributions underscore the importance of considering reservoir dynamics beyond simply the half-life. We calculate blip amplitudes and frequencies by computing complete viral load probability distributions, and study the duration of viral blips via direct numerical simulation. We find that our model qualitatively reproduces short small-amplitude blips detected in clinical studies of treated HIV infection. Stochastic models of this type provide insight into treatment-outcome variability that cannot be found from deterministic models

    Putative DHHC-Cysteine-Rich Domain S-Acyltransferase in Plants

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    Protein S-acyltransferases (PATs) containing Asp-His-His-Cys within a Cys-rich domain (DHHC-CRD) are polytopic transmembrane proteins that are found in eukaryotic cells and mediate the S-acylation of target proteins. S-acylation is an important secondary and reversible modification that regulates the membrane association, trafficking and function of target proteins. However, little is known about the characteristics of PATs in plants. Here, we identified 804 PATs from 31 species with complete genomes. The analysis of the phylogenetic relationships suggested that all of the PATs fell into 8 groups. In addition, we analysed the phylogeny, genomic organization, chromosome localisation and expression pattern of PATs in Arabidopsis, Oryza sative, Zea mays and Glycine max. The microarray data revealed that PATs genes were expressed in different tissues and during different life stages. The preferential expression of the ZmPATs in specific tissues and the response of Zea mays to treatments with phytohormones and abiotic stress demonstrated that the PATs play roles in plant growth and development as well as in stress responses. Our data provide a useful reference for the identification and functional analysis of the members of this protein family

    Magnet therapy for the relief of pain and inflammation in rheumatoid arthritis (CAMBRA): A randomised placebo-controlled crossover trial

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    <p>Abstract</p> <p>Background</p> <p>Rheumatoid arthritis is a common inflammatory autoimmune disease. Although disease activity may be managed effectively with prescription drugs, unproven treatments such as magnet therapy are sometimes used as an adjunct for pain control. Therapeutic devices incorporating permanent magnets are widely available and easy to use. Magnets may also be perceived as a more natural and less harmful alternative to analgesic compounds. Of interest to health service researchers is the possibility that magnet therapy might help to reduce the economic burden of managing chronic musculoskeletal disorders. Magnets are extremely cheap to manufacture and prolonged treatment involves a single cost. Despite this, good quality scientific evidence concerning the safety, effectiveness and cost-effectiveness of magnet therapy is scarce. The primary aim of the CAMBRA trial is to investigate the effectiveness of magnet therapy for relieving pain and inflammation in rheumatoid arthritis.</p> <p>Methods/Design</p> <p>The CAMBRA trial employs a randomised double-blind placebo-controlled crossover design. Participant will each wear four devices: a commercially available magnetic wrist strap; an attenuated wrist strap; a demagnetised wrist strap; and a copper bracelet. Device will be allocated in a randomised sequence and each worn for five weeks. The four treatment phases will be separated by wash out periods lasting one week. Both participants and researchers will be blind, as far as feasible, to the allocation of experimental and control devices. In total 69 participants will be recruited from general practices within the UK. Eligible patients will have a verified diagnosis of rheumatoid arthritis that is being managed using drugs, and will be experiencing chronic pain. Outcomes measured will include pain, inflammation, disease activity, physical function, medication use, affect, and health related costs. Data will be collected using questionnaires, diaries, manual pill counts and blood tests.</p> <p>Discussion</p> <p>Magnetism is an inherent property of experimental devices which is hard to conceal. The use of multiple control devices, including a copper bracelet, represents a concerted attempt to overcome methodological limitations associated with trials in this field. The trial began in July 2007. At the time of submission (August 2008) recruitment has finished, with 70 trial participants, and data collection is almost complete.</p> <p>Trial Registration</p> <p>Current Controlled Trials ISRCTN51459023</p
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