1,537 research outputs found

    Identifying H-2b-restricted CD4+ T Lymphocyte Recognition Epitopes Within Simian Virus 40 Large Tumor Antigen

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    CD4+ T lymphocytes play a vital role in immune system function but little is known about their role in controlling SV40 T ag-induced tumors in C57BL/6 mice. In order to better investigate their role in the control of tumors, it is necessary to identify CD4 epitope(s) within the Tag. Four CDS epitopes have been identified but the CD4 epitopes have not been identified. To facilitate the identification of the epitopes, T cell hybridomas containing a Lacz reporter gene were used. CD4+ hybridoma clones capable of recognizing SV 40 Large Tumor Antigen (T ag) were obtained from heterogeneous populations through serial dilution and screening with a colorimetric (CPRG) assay in which bone marrow-derived dendritic cells were pulsed with purified SV 40 T ag protein. To map the location of the epitope target of each clone, four of the clones were chosen for use in a screening assay utilizing a library of overlapping synthetic 15mer peptides representing the entire SV 40 T ag amino acid sequence. The identification of such CD4+ epitopes within the T ag will make it possible to determine the immunogenic and regulatory properties of each epitope (in vivo) and determine whether differences in reactivity demonstrated by the various hybridoma clones against the purified SV 40 T ag protein are epitope or hybrid dependent

    Cost-effectiveness of managing Natura 2000 sites: an exploratory study for Finland, Germany, the Netherlands and Poland

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    Natura 2000 sites are expected to assure the long-term survival of Europe's most valuable and threatened species and habitats. It follows that successful management of the sites is of great importance. Next to goal attainment, cost-effectiveness is increasingly recognised as a key requirement for gaining social and political acceptance for costly conservation measures. We identify and qualitatively examine issues of cost-effectiveness related to the design and implementation of management measures in Natura 2000 sites in Finland, Germany, the Netherlands and Poland. Given the wide variety of management design and implementation options within the four countries, our study is purely of an exploratory nature. We derive recommendations for improving the cost-effectiveness of management in Natura 2000 sites and for future research. Examples of policy recommendations include guaranteeing the availability of funds for longer periods, and ensuring the appropriate allocation of funds between the different tasks of designing and implementing management plans. Further research should examine the cost-effectiveness of controversial suggestions such as, for example, more tailored payment schemes for conservation measures that result in higher ecological outputs but are costly to administer. Moreover, more research is needed to better understand how rules for administrations, as well as rules and governance structures for tasks within administrations, should be designed

    Metabolites that confirm induction and release of dormancy phases in sweet cherry buds

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    Here we report on metabolites found in a targeted profiling of ‘Summit’ flower buds for nine years, which could be indicators for the timing of endodormancy release (t1) and beginning of ontogenetic development (t1*). Investigated metabolites included chrysin, arabonic acid, pentose acid, sucrose, abscisic acid (ABA), and abscisic acid glucose ester (ABA-GE). Chrysin and water content showed an almost parallel course between leaf fall and t1*. After ‘swollen bud’, water content raised from ~60 to ~80% at open cluster, while chrysin content decreased and lost its function as an acetylcholinesterase inhibitor. Both parameters can be suitable indicators for t1*. Arabonic acid showed a clear increase after t1*. Pentose acid would be a suitable metabolite to identify t1 and t1*, but would not allow describing the ecodormancy phase, because of its continuously low value during this time. Sucrose reached a maximum during ecodormancy and showed a significant correlation with air temperature, which confirms its cryoprotective role in this phase. The ABA content showed maximum values during endodormancy and decreased during ecodormancy, reaching 50% of its content t1 at t1*. It appears to be the key metabolite to define the ecodormancy phase. The ABA-GE was present at all stages and phases and was much higher than the ABA content and is a readily available storage pool in cherry buds.Peer Reviewe

    Metabolites in Cherry Buds to Detect Winter Dormancy

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    Winter dormancy is still a “black box” in phenological models, because it evades simple observation. This study presents the first step in the identification of suitable metabolites which could indicate the timing and length of dormancy phases for the sweet cherry cultivar ‘Summit’. Global metabolite profiling detected 445 named metabolites in flower buds, which can be assigned to different substance groups such as amino acids, carbohydrates, phytohormones, lipids, nucleotides, peptides and some secondary metabolites. During the phases of endo- and ecodormancy, the energy metabolism in the form of glycolysis and the tricarboxylic acid (TCA) cycle was shut down to a minimum. However, the beginning of ontogenetic development was closely related to the up-regulation of the carbohydrate metabolism and thus to the generation of energy for the growth and development of the sweet cherry buds. From the 445 metabolites found in cherry buds, seven were selected which could be suitable markers for the ecodormancy phase, whose duration is limited by the date of endodormancy release (t1) and the beginning of ontogenetic development (t1*). With the exception of abscisic acid (ABA), which has been proven to control bud dormancy, all of these metabolites show nearly constant intensity during this phase.Peer Reviewe

    The International Phenological Garden network (1959 to 2021): its 131 gardens, cloned study species, data archiving, and future

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    Collaborative networks that involve the compilation of observations from diverse sources can provide important data, but are difficult to maintain over long periods. The International Phenological Garden (IPG) network, begun in 1959 and still functioning 60~years later, has been no exception. Here we document its history, its monitored 23 species (initially all propagated by cloning), and the locations and years of data contribution of its 131 gardens, of which 63 from 19 countries contributed data in 2021. The decision to use clones, rather than multiple, locally adapted individuals, was based on the idea that this would \textquotedblcontrol\textquotedbl for genetic effects, and it~affects the applicability of the data and duration of the network. We also describe the overlap among the IPG network, the Pan-European Phenology network (PEP725), and the phenological data offered by the German Weather Service. Sustainable data storage and accessibility, as well as the continued monitoring of all 23 species/clones, are under discussion at the moment, as is the fate of other phenological networks, despite a politically mandatory plant-based climate-change monitoring

    Chromium coated silicon nitride electron beam exit window

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    A Si3N4 membrane with a thin Cr coating is proposed and demonstrated as an electron beam exit window. On average, 85% electron power transmission efficiency was achieved with a 1 μm thick Si3N4 membrane coated with 1 μm thick Cr and the membrane sustained a beam current of up to 3 mA at 60 keV electron energy for the continuous operation of 3 min. However, for an uncoated membrane of same thickness, the average electron power transmission efficiency was 71% and the maximum beam current sustained was 800 μA. It was also shown that a one micron thick Si3N4 square membrane window of 10 mm × 10 mm could withstand a differential pressure of 1.3 bars.The work carried out at Brunel University was co-funded by the EC Seventh Framework Programme theme FP7-SST-2011-RTD-1 for the DEECON project (grant number 284745)

    Drug-Induced Hematologic Syndromes

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    Objective. Drugs can induce almost the entire spectrum of hematologic disorders, affecting white cells, red cells, platelets, and the coagulation system. This paper aims to emphasize the broad range of drug-induced hematological syndromes and to highlight some of the newer drugs and syndromes. Methods. Medline literature on drug-induced hematologic syndromes was reviewed. Most reports and reviews focus on individual drugs or cytopenias. Results. Drug-induced syndromes include hemolytic anemias, methemoglobinemia, red cell aplasia, sideroblastic anemia, megaloblastic anemia, polycythemia, aplastic anemia, leukocytosis, neutropenia, eosinophilia, immune thrombocytopenia, microangiopathic syndromes, hypercoagulability, hypoprothrombinemia, circulating anticoagulants, myelodysplasia, and acute leukemia. Some of the classic drugs known to cause hematologic abnormalities have been replaced by newer drugs, including biologics, accompanied by their own syndromes and unintended side effects. Conclusions. Drugs can induce toxicities spanning many hematologic syndromes, mediated by a variety of mechanisms. Physicians need to be alert to the potential for iatrogenic drug-induced hematologic complications

    The Role of Threonine Deaminase/Dehydratase in Winter Dormancy in Sweet Cherry Buds

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    The determination of the endodormancy release and the beginning of ontogenetic development is a challenge, because these are non-observable stages. Changes in protein activity are important aspects of signal transduction. The conversion of threonine to 2-oxobutanoate is the first step towards isoleucine (Ile) biosynthesis, which promote growth and development. The reaction is catalyzed by threonine deaminase/dehydratase (TD). This study on TD activity was conducted at the experimental sweet cherry orchard at Berlin-Dahlem. Fresh (FW), dry weight (DW), water content (WC), and the specific TD activity for the cherry cultivars Summit, Karina and Regina were conducted from flower bud samples between October and April. The content of asparagine (Asn), aspartic acid (Asp), Ile, and valine (Val) were exemplarily shown for Summit. In buds of Summit and Karina, the TD activity was one week after the beginning of the ontogenetic development (t1*), significantly higher compared to samplings during endo- and ecodormancy. Such “peak” activity did not occur in the buds of Regina; TD tended for a longer time (day of year, DOY 6–48) to a higher activity, compared to the time DOY 287–350. For the date “one week after t1*”, the upregulation of TD, the markedly increase of the Ile and Val content, and the increase of the water content in the buds, all this enzymatically confirms the estimated start of the ontogenetic development (t1*) in sweet cherry buds.Peer Reviewe

    Two-body electrodisintegration of the three-nucleon bound state with Δ-isobar excitation

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    Electrodisintegration of the three-nucleon bound state with two-body final states is described. The description uses nucleon degrees of freedom extended to include the excitation of a single nucleon to a Δ isobar. The baryonic interaction and the electromagnetic current couple nucleonic states and states with a Δ isobar. Exact solutions of three-particle scattering equations are employed for the initial and final states of the reactions; due to the excitation of the Δ isobar an effective three-nucleon force is included. The current has one-baryon and two-baryon contributions. Theoretical predictions for the reactions with selected kinematic specifications are given. The role of the Δ isobar in the description of the considered processes is discussed and its effect on observables is quantitatively isolated
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