1,916 research outputs found

    The heat shock response and humoral immune response are mutually antagonistic in honey bees

    Full text link
    The honey bee is of paramount importance to humans in both agricultural and ecological settings. Honey bee colonies have suffered from increased attrition in recent years, stemming from complex interacting stresses. Defining common cellular stress responses elicited by these stressors represents a key step in understanding potential synergies. The proteostasis network is a highly conserved network of cellular stress responses involved in maintaining the homeostasis of protein production and function. Here, we have characterized the Heat Shock Response (HSR), one branch of this network, and found that its core components are conserved. In addition, exposing bees to elevated temperatures normally encountered by honey bees during typical activities results in robust HSR induction with increased expression of specific heat shock proteins that was variable across tissues. Surprisingly, we found that heat shock represses multiple immune genes in the abdomen and additionally showed that wounding the cuticle of the abdomen results in decreased expression of multiple HSR genes in proximal and distal tissues. This mutually antagonistic relationship between the HSR and immune activation is unique among invertebrates studied to date and may promote understanding of potential synergistic effects of disparate stresses in this critical pollinator and social insects more broadly

    Can Teachers Accurately Predict Student Performance?

    Get PDF
    In two studies, we examined the effect of professional development to improve mathematics instruction on the accuracy of teachers\u27 monitoring of student learning. Study 1 was conducted with 36 teachers participating in three years of professional development. Judgment accuracy was influenced by the fidelity with which what was learned in the professional development. Study 2 was conducted with 64 teachers from 8 schools, which were randomly assigned to receive professional development or serve as a control. Judgment accuracy was greater for teachers receiving professional development than for teachers who did not and teachers were better to predict students\u27 computational skills

    Is 8:30 a.m. Still Too Early to Start School? A 10:00 a.m. School Start Time Improves Health and Performance of Students Aged 13-16.

    Get PDF
    While many studies have shown the benefits of later school starts, including better student attendance, higher test scores, and improved sleep duration, few have used starting times later than 9:00 a.m. Here we report on the implementation and impact of a 10 a.m. school start time for 13 to 16-year-old students. A 4-year observational study using a before-after-before (A-B-A) design was carried out in an English state-funded high school. School start times were changed from 8:50 a.m. in study year 0, to 10 a.m. in years 1-2, and then back to 8:50 a.m. in year 3. Measures of student health (absence due to illness) and academic performance (national examination results) were used for all students. Implementing a 10 a.m. start saw a decrease in student illness after 2 years of over 50% (p < 0.0005 and effect size: Cohen's d = 1.07), and reverting to an 8:50 a.m. start reversed this improvement, leading to an increase of 30% in student illness (p < 0.0005 and Cohen's d = 0.47). The 10:00 a.m. start was associated with a 12% increase in the value-added number of students making good academic progress (in standard national examinations) that was significant (<0.0005) and equivalent to 20% of the national benchmark. These results show that changing to a 10:00 a.m. high school start time can greatly reduce illness and improve academic performance. Implementing school start times later than 8:30 a.m., which may address the circadian delay in adolescents' sleep rhythms more effectively for evening chronotypes, appears to have few costs and substantial benefits

    Impaired CD8 T cell memory and CD4 T cell primary responses in IL-7Rα mutant mice

    Get PDF
    Loss of interleukin (IL)-7 or the IL-7 receptor alpha (IL-7Rα, CD127) results in severe immunodeficiencies in mice and humans. To more precisely identify signals governing IL-7 function in vivo, we have disrupted the IL-7Rα Y449XXM motif in mice by knock-in mutagenesis (IL-7Rα449F). Thymic precursors were reduced in number in IL-7Rα449F mice, but in marked contrast to IL-7Rα−/− knockout mice, thymocytes and peripheral T cells developed normally. Strikingly, Listeria infection revealed that CD4 and CD8 T cells had different requirements for IL-7Rα signals. CD4 T cells failed to mount a primary response, but despite normal CD8 primary responses, maintenance of CD8 memory was impaired in IL-7Rα449F mice. Furthermore, we show that Bcl-2 is IL-7Rα Y449 independent and insufficient for IL-7–mediated maintenance of CD8 memory

    Thinking like a man? The cultures of science

    Get PDF
    Culture includes science and science includes culture, but conflicts between the two traditions persist, often seen as clashes between interpretation and knowledge. One way of highlighting this false polarity has been to explore the gendered symbolism of science. Feminism has contributed to science studies and the critical interrogation of knowledge, aware that practical knowledge and scientific understanding have never been synonymous. Persisting notions of an underlying unity to scientific endeavour have often impeded rather than fostered the useful application of knowledge. This has been particularly evident in the recent rise of molecular biology, with its delusory dream of the total conquest of disease. It is equally prominent in evolutionary psychology, with its renewed attempts to depict the fundamental basis of sex differences. Wars over science have continued to intensify over the last decade, even as our knowledge of the political, economic and ideological significance of science funding and research has become ever more apparent

    Ozone depletion events observed in the high latitude surface layer during the TOPSE aircraft program

    Get PDF
    During the Tropospheric Ozone Production about the Spring Equinox (TOPSE) aircraft program, ozone depletion events (ODEs) in the high latitude surface layer were investigated using lidar and in situ instruments. Flight legs of 100 km or longer distance were flown 32 times at 30 m altitude over a variety of regions north of 58° between early February and late May 2000. ODEs were found on each flight over the Arctic Ocean but their occurrence was rare at more southern latitudes. However, large area events with depletion to over 2 km altitude in one case were found as far south as Baffin Bay and Hudson Bay and as late as 22 May. There is good evidence that these more southern events did not form in situ but were the result of export of ozone-depleted air from the surface layer of the Arctic Ocean. Surprisingly, relatively intact transport of ODEs occurred over distances of 900–2000 km and in some cases over rough terrain. Accumulation of constituents in the frozen surface over the dark winter period cannot be a strong prerequisite of ozone depletion since latitudes south of the Arctic Ocean would also experience a long dark period. Some process unique to the Arctic Ocean surface or its coastal regions remains unidentified for the release of ozone-depleting halogens. There was no correspondence between coarse surface features such as solid ice/snow, open leads, or polynyas with the occurrence of or intensity of ozone depletion over the Arctic or subarctic regions. Depletion events also occurred in the absence of long-range transport of relatively fresh “pollution” within the high latitude surface layer, at least in spring 2000. Direct measurements of halogen radicals were not made. However, the flights do provide detailed information on the vertical structure of the surface layer and, during the constant 30 m altitude legs, measurements of a variety of constituents including hydroxyl and peroxy radicals. A summary of the behavior of these constituents is made. The measurements were consistent with a source of formaldehyde from the snow/ice surface. Median NOx in the surface layer was 15 pptv or less, suggesting that surface emissions were substantially converted to reservoir constituents by 30 m altitude and that ozone production rates were small (0.15–1.5 ppbv/d) at this altitude. Peroxyacetylnitrate (PAN) was by far the major constituent of NOy in the surface layer independent of the ozone mixing ratio

    Nonradioactive heteroduplex tracking assay for the detection of minority-variant chloroquine-resistant Plasmodium falciparum in Madagascar

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Strains of <it>Plasmodium falciparum </it>genetically resistant to chloroquine (CQ) due to the presence of <it>pfcrt </it>76T appear to have been recently introduced to the island of Madagascar. The prevalence of such resistant genotypes is reported to be low (< 3%) when evaluated by conventional PCR. However, these methods are insensitive to low levels of mutant parasites present in patients with polyclonal infections. Thus, the current estimates may be an under representation of the prevalence of the CQ-resistant <it>P. falciparum </it>isolates on the island. Previously, minority variant chloroquine resistant parasites were described in Malawian patients using an isotopic heteroduplex tracking assay (HTA), which can detect <it>pfcrt </it>76T-bearing <it>P. falciparum </it>minority variants in individual patients that were undetectable by conventional PCR. However, as this assay required a radiolabeled probe, it could not be used in many resource-limited settings.</p> <p>Methods</p> <p>This study describes a digoxigenin (DIG)-labeled chemiluminescent heteroduplex tracking assay (DIG-HTA) to detect <it>pfcrt </it>76T-bearing minority variant <it>P. falciparum</it>. This assay was compared to restriction fragment length polymorphism (RFLP) analysis and to the isotopic HTA for detection of genetically CQ-resistant parasites in clinical samples.</p> <p>Results</p> <p>Thirty one clinical <it>P. falciparum </it>isolates (15 primary isolates and 16 recurrent isolates) from 17 Malagasy children treated with CQ for uncomplicated malaria were genotyped for the <it>pfcrt </it>K76T mutation. Two (11.7%) of 17 patients harboured genetically CQ-resistant <it>P. falciparum </it>strains after therapy as detected by HTA. RFLP analysis failed to detect any <it>pfcrt </it>K76T-bearing isolates.</p> <p>Conclusion</p> <p>These findings indicate that genetically CQ-resistant <it>P. falciparum </it>are more common than previously thought in Madagascar even though the fitness of the minority variant <it>pfcrt </it>76T parasites remains unclear. In addition, HTAs for malaria drug resistance alleles are promising tools for the surveillance of anti-malarial resistance. The use of a non-radioactive label allows for the use of HTAs in malaria endemic countries.</p

    MPI-DING reference glasses for in situ microanalysis: New reference values for element concentrations and isotope ratios

    Get PDF
    We present new analytical data of major and trace elements for the geological MPI-DING glasses KL2-G, ML3B-G, StHs6/80-G, GOR128-G, GOR132-G, BM90/21-G, T1-G, and ATHO-G. Different analytical methods were used to obtain a large spectrum of major and trace element data, in particular, EPMA, SIMS, LA-ICPMS, and isotope dilution by TIMS and ICPMS. Altogether, more than 60 qualified geochemical laboratories worldwide contributed to the analyses, allowing us to present new reference and information values and their uncertainties (at 95% confidence level) for up to 74 elements. We complied with the recommendations for the certification of geological reference materials by the International Association of Geoanalysts (IAG). The reference values were derived from the results of 16 independent techniques, including definitive (isotope dilution) and comparative bulk (e.g., INAA, ICPMS, SSMS) and microanalytical (e.g., LA-ICPMS, SIMS, EPMA) methods. Agreement between two or more independent methods and the use of definitive methods provided traceability to the fullest extent possible. We also present new and recently published data for the isotopic compositions of H, B, Li, O, Ca, Sr, Nd, Hf, and Pb. The results were mainly obtained by high-precision bulk techniques, such as TIMS and MC-ICPMS. In addition, LA-ICPMS and SIMS isotope data of B, Li, and Pb are presented. Copyright 2006 by the American Geophysical Union

    A Single cis Element Maintains Repression of the Key Developmental Regulator Gata2

    Get PDF
    In development, lineage-restricted transcription factors simultaneously promote differentiation while repressing alternative fates. Molecular dissection of this process has been challenging as transcription factor loci are regulated by many trans-acting factors functioning through dispersed cis elements. It is not understood whether these elements function collectively to confer transcriptional regulation, or individually to control specific aspects of activation or repression, such as initiation versus maintenance. Here, we have analyzed cis element regulation of the critical hematopoietic factor Gata2, which is expressed in early precursors and repressed as GATA-1 levels rise during terminal differentiation. We engineered mice lacking a single cis element −1.8 kb upstream of the Gata2 transcriptional start site. Although Gata2 is normally repressed in late-stage erythroblasts, the −1.8 kb mutation unexpectedly resulted in reactivated Gata2 transcription, blocked differentiation, and an aberrant lineage-specific gene expression pattern. Our findings demonstrate that the −1.8 kb site selectively maintains repression, confers a specific histone modification pattern and expels RNA Polymerase II from the locus. These studies reveal how an individual cis element establishes a normal developmental program via regulating specific steps in the mechanism by which a critical transcription factor is repressed
    corecore