58 research outputs found

    Bridging the gap between school and out-of-school science: A Making pedagogical approach

    Get PDF
    Making provides a beneficial learning environment that requires skills and knowledge from the areas of science, technology, engineering, and mathematics to design and construct a product or an artefact. In this paper the maker approach reflects on the pedagogical potential of learning through the design and deployment of an automated system that monitors and records environmental parameters in lakes and rivers. IoT technologies are used to connect schools with natural ecosystems, providing the opportunity to students to be actively involved in designing and developing technology artefacts to experiment with, and further, in the formulation of research questions, and in the processing and interpretation of research results and measurements. The study contributes to the research literature on bridging the gap between the school and out-of-school science

    Local measurements of the mean interstellar polarization at high Galactic latitudes

    Get PDF
    Very little information exists concerning the properties of the interstellar medium (ISM)-induced starlight polarization at high Galactic latitudes. Future optopolarimetric surveys promise to fill this gap. We conduct a small-scale pathfinding survey designed to identify the average polarization properties of the diffuse ISM locally, at regions with the lowest dust content. We perform deep optopolarimetric surveys within three ~15â€Č× 15â€Č regions located at b > 48° using the RoboPol polarimeter. The observed samples of stars are photometrically complete to ~16 mag in the R-band. The selected regions exhibit low total reddening compared to the majority of high-latitude sightlines. We measure the level of systematic uncertainty for all observing epochs and find it to be 0.1% in fractional linear polarization, p. The majority of individual stellar measurements have low signal-to-noise ratios. However, our survey strategy enables us to locate the mean fractional linear polarization p_(mean) in each of the three regions. The region with lowest dust content yields p_(mean) = (0.054 ± 0.038)%, not significantly different from zero. We find significant detections for the remaining two regions of: p_(mean) = (0.113 ± 0.036)% and p_(mean) = (0.208 ± 0.044)%. Using a Bayesian approach, we provide upper limits on the intrinsic spread of the small-scale distributions of q and u. At the detected p_(mean) levels, the determination of the systematic uncertainty is critical for the reliability of the measurements. We verify the significance of our detections with statistical tests, accounting for all sources of uncertainty. Using publicly available HI emission data, we identify the velocity components that most likely account for the observed p_(mean) and find their morphologies to be misaligned with the orientation of the mean polarization at a spatial resolution of 10â€Č. We find indications that the standard upper envelope of p with reddening underestimates the maximum p at very low E(B–V) (≀0.01 mag)

    Immunolocalization of dually phosphorylated MAPKs in dividing root meristem cells of Vicia faba, Pisum sativum, Lupinus luteus and Lycopersicon esculentum

    Get PDF
    Key message In plants, phosphorylated MAPKs display constitutive nuclear localization; however, not all studied plant species show co-localization of activated MAPKs to mitotic microtubules. Abstract The mitogen-activated protein kinase (MAPK) signaling pathway is involved not only in the cellular response to biotic and abiotic stress but also in the regulation of cell cycle and plant development. The role of MAPKs in the formation of a mitotic spindle has been widely studied and the MAPK signaling pathway was found to be indispensable for the unperturbed course of cell division. Here we show cellular localization of activated MAPKs (dually phosphorylated at their TXY motifs) in both interphase and mitotic root meristem cells of Lupinus luteus, Pisum sativum, Vicia faba (Fabaceae) and Lycopersicon esculentum (Solanaceae). Nuclear localization of activated MAPKs has been found in all species. Colocalization of these kinases to mitotic microtubules was most evident in L. esculentum, while only about 50 % of mitotic cells in the root meristems of P. sativum and V. faba displayed activated MAPKs localized to microtubules during mitosis. Unexpectedly, no evident immunofluorescence signals at spindle microtubules and phragmoplast were noted in L. luteus. Considering immunocytochemical analyses and studies on the impact of FR180204 (an inhibitor of animal ERK1/2) on mitotic cells, we hypothesize that MAPKs may not play prominent role in the regulation of microtubule dynamics in all plant species

    A Bacterial Acetyltransferase Destroys Plant Microtubule Networks and Blocks Secretion

    Get PDF
    The eukaryotic cytoskeleton is essential for structural support and intracellular transport, and is therefore a common target of animal pathogens. However, no phytopathogenic effector has yet been demonstrated to specifically target the plant cytoskeleton. Here we show that the Pseudomonas syringae type III secreted effector HopZ1a interacts with tubulin and polymerized microtubules. We demonstrate that HopZ1a is an acetyltransferase activated by the eukaryotic co-factor phytic acid. Activated HopZ1a acetylates itself and tubulin. The conserved autoacetylation site of the YopJ / HopZ superfamily, K289, plays a critical role in both the avirulence and virulence function of HopZ1a. Furthermore, HopZ1a requires its acetyltransferase activity to cause a dramatic decrease in Arabidopsis thaliana microtubule networks, disrupt the plant secretory pathway and suppress cell wall-mediated defense. Together, this study supports the hypothesis that HopZ1a promotes virulence through cytoskeletal and secretory disruption
    • 

    corecore