The Role of Natural Calcium Oxalate Crystals in Plant Defense Against Chewing Insects

Calcium oxalate is the most abundant insoluble mineral found in plants and it is common among many plant families. Calcium oxalate crystals in plants can appear as irregular rectangles, spiked balls, or needles. The formidable appearance of these crystals has lead to speculation that they might serve as a form of pest control by deterring chewing insects. We utilized mutant plant lines to assess the effects of plant calcium oxalate crystals on the survival and feeding habits of chewing insects. We have taken advantage of calcium oxalate-deficient (cod) mutants of the barrel medic, Medicago truncatula Calcium oxalate crystals accumulate in wildtype M. truncatula leaves along the vascular strands of secondary veins. Results demonstrate that beet army-worm, Spodoptera exigua, larvae that feed on M. truncatula cod mutants with reduced levels of calcium oxalate crystals grow faster and larger than insects that feed on normal wildtype plants. Pupae formed by larvae raised on cod plants are significantly larger than those raised on the wildtype plants. The results of two-way choice tests indicate that older( 4\u27h instar or later) S. exigua larvae prefer to feed on leaves lacking calcium oxalate, whereas young larvae (2nd instar or earlier) show no feeding preference. This development-specific feeding preference is perhaps due to the feeding habits of the herbivore; young larvae typically feed between secondary veins, away from areas where the calcium oxalate crystals are localized. Accumulation of RNA transcripts encoding wound-inducible gene products is normal in the cod mutants, suggesting that these plants are not altered in their ability to sense or respond to wounding by insect herbivores. Because calcium oxalate crystals seem to serve as a feeding deterrent to insects, understanding how they are made and distributed could ultimately lead to novel, environmentally sound strategies for improving insect resistance in crop plant species

The Jülich High Brilliance Neutron Source Project – A challenge for neutron optics

Neutrons can be produced by fission in nuclear reactors, by spallation using high-power proton accelerators, and by nuclear reactions with low-energy proton accelerators. While the first two techni¬ques can offer the highest neutron flux production, current state-of-the-art accelerator technology offers the opportunity for a new landscape of novel and unique high-brilliance neutron sources based on low-energy proton accelerators. The Jülich Centre for Neutron Science has started a project to develop and design compact accelerator driven high-brilliance neutron sources as an efficient and cost effective alternative to current low- and medium-flux reactor and spallation sources. Such compact sources have the potential to offer access of science and industry to neutrons as local national or regional medium-flux, but high-brilliance neutron facilities. The project aims to deliver a “High-Brilliance Neutron Source (HBS)”, where a compact neutron production and moderator system provide thermal and cold neutrons with high brilliance efficiently extracted in an optimized neutron transport system. With shaping the experiment from the source to the detector a holistic neutron experiment could be set-up for the specific scientific requirements in a flexible and efficient way for the neutron user. This presents a particular challenge for the appropriate neutron transport systems to deliver the full brilliance of the source to the sample. Neutron lenses, ballistic guides and focusing systems will be requested to minimize any loss in brilliance and neutron flux. In this report we will present a brief outline of the JCNS HBS project and discuss resulting requirements on neutron transport devices

Conceptual Design Report Jülich High Brilliance Neutron Source (HBS)

Neutrons are an essential tool for science and industry for probing the structure and dynamics of matter from the mesoscale to the picoscale and from seconds to femtoseconds. In Europe research, industry and society benefit from a globally unique environment of various neutron sources with the flagship facilities ILL in Grenoble, France, and ESS in Lund, Sweden. The latter is currently under construction and will represent the world’s most powerful neutron facility. The unique capabilities of neutrons and the European neutron infrastructure have been highlighted in reports by the European Neutron Scattering Association (ENSA) and the ESFRI Neutron Landscape Group recently. More than 8000 users utilize the available neutron sources in Europe, requesting nearly twice the available capacity offered per year. This high demand for research with neutrons is managed by peer review processes established to permit access to the facilities resulting in a highly competitive situation which sometimes hampers access by well-qualified applicants. The main processes to release neutrons from atomic nuclei are: (i) fission in nuclear reactors, (ii) spallation using high-power proton accelerators, and (iii) nuclear reactions induced by low-energy protons or deuterons. The first two techniques are used very successfully in Europe and offer the highest neutron source strength with versatile options. In view of the continuously high demand for neutron experiments by science and industry and the phasing out of existing reactor-based neutron facilities in Europe in the near future, new solutions and strategies are required to provide sustainable and effective access to neutrons in Europe. New neutron infrastructures have to provide novel capabilities not offered by the present-day facilities based on the ageing suite of research reactors in Europe. Enhanced performance does not necessarily rely on increased source strength, which goes hand-in-hand with cost increase, but can include improved flexibility and accessibility, specialization on particular important societal challenges or optimization on brilliance for small beams. In particular, cost-effective solutions are required to compensate the potential capacity loss and complement high-flux sources such as the new ESS spallation neutron source. The High Brilliance neutron Source (HBS) project will demonstrate the technical and operational concept for a neutron infrastructure based on a low-energy proton accelerator. HBS is designed as a very flexible neutron infrastructure with neutron beams optimized for brilliance. It will host a full suite of highly competitive instruments. Thus HBS will be capable to serve as a national or regional highly attractive neutron research centre. The HBS source will benet of state-of-the-art accelerator technology, combined with unique target-moderator concepts. HBS will mark a change in paradigm for research with neutrons where every individual neutron instrument will have its own neutron source with optimized pulse structure and a moderator adapted to the specific requirements of the instrument. Thus it will provide a unique and attractive option for achieving optimum and efficient brilliance for all neutron experiments at a lower cost compared to present-day large-scale neutron facilities

Deficiency or inhibition of oxygen sensor Phd1 induces hypoxia tolerance by reprogramming basal metabolism.

HIF prolyl hydroxylases (PHD1-3) are oxygen sensors that regulate the stability of the hypoxia-inducible factors (HIFs) in an oxygen-dependent manner. Here, we show that loss of Phd1 lowers oxygen consumption in skeletal muscle by reprogramming glucose metabolism from oxidative to more anaerobic ATP production through activation of a Pparalpha pathway. This metabolic adaptation to oxygen conservation impairs oxidative muscle performance in healthy conditions, but it provides acute protection of myofibers against lethal ischemia. Hypoxia tolerance is not due to HIF-dependent angiogenesis, erythropoiesis or vasodilation, but rather to reduced generation of oxidative stress, which allows Phd1-deficient myofibers to preserve mitochondrial respiration. Hypoxia tolerance relies primarily on Hif-2alpha and was not observed in heterozygous Phd2-deficient or homozygous Phd3-deficient mice. Of medical importance, conditional knockdown of Phd1 also rapidly induces hypoxia tolerance. These findings delineate a new role of Phd1 in hypoxia tolerance and offer new treatment perspectives for disorders characterized by oxidative stress