140 research outputs found

    Transgenic Petunia for Iron Deficiency in Alkaline Environments

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    Iron is an essential nutrient for all plants. However, terrestrial plants often suffer from iron deficiency in alkaline soil due to its extremely low solubility. Alkaline soil accounts for about 30% of all cultivated ground in the world. Plants have evolved two distinct strategies, I and II, for iron uptake from the soil. Dicots and non-graminaceous monocots use Strategy I, which is primarily based on the reduction of iron(III) to iron(II) and the uptake of iron(II) by the iron-regulated transporter, IRT1. In contrast, graminaceous plants use Strategy II to efficiently acquire insoluble iron(III). Strategy II comprises the synthesis and secretion of iron-chelating phytosiderophores, such as mugineic acids and the Yellow Stripe 1 transporter proteins of the iron(III)-phytosiderophore complex. Barley, which exhibits the highest tolerance to iron deficiency in alkaline soil among graminaceous plants, utilizes mugineic acids and the specific iron(III)-mugineic acids transporter, HvYS1. In this study, we established the transgenic plant Petunia hybrida, which originally had only Strategy I, by introducing the HvYS1 transporter gene derived from barley. When the transgenic plants were grown hydroponically in media containing the iron(III)-2′-deoxymugineic acid complex, free 2′-deoxymugineic acid and its iron(III) complex were detected in the root extract of the transgenic plant by electrospray ionization-Fourier transform-ion cyclotron resonance mass spectrometry. The growth of the transgenic petunia was significantly better than that of the control host in alkaline conditions. Consequently, the transgenic plant acquired a significantly enhanced tolerance to alkaline hydroponic media in the presence of the iron(III)-2′-deoxymugineic acid complex. Furthermore, the flower color of the transgenic plant deepened. The results showed that iron-phytosiderophore complexes and their transporters can potentially be utilized to overcome the worldwide iron uptake problems to diverse plant species that are found in areas with alkaline conditions

    Structural element responsible for the Fe(III)–phytosiderophore specific transport by HvYS1 transporter in barley

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    AbstractHordeum vulgare L. yellow stripe 1 (HvYS1) is a selective transporter for Fe(III)–phytosiderophores, involved in primary iron acquisition from soils in barley roots. In contrast, Zea mays yellow stripe 1 (ZmYS1) in maize possesses broad substrate specificity, despite a high homology with HvYS1. Here we revealed, by assessing the transport activity of a series of HvYS1–ZmYS1 chimeras, that the outer membrane loop between the sixth and seventh transmembrane regions is essential for substrate specificity. Circular dichroism spectra indicated that a synthetic peptide corresponding to the loop of HvYS1 forms an α-helix in solution, whereas that of ZmYS1 is flexible. We propose that the structural difference at this particular loop determines the substrate specificity of the HvYS1 transporter

    The Stretcher Operation of KSR (NUCLEAR SCIENCE RESEARCH FACILITY-Particle and Photon Beams)

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    The electron ring KSR has been utilized as a pulse stretcher of the 100 MeV S-band electron linac. The duty factor of the electron beam has been increased drastically more than 90% from 2 10-5

    The Development and Assessment on the Social Studies Handbook for Supporting Teacher’s Lesson Planning and Improvement : A Content Structure of Handbook which can be Applied to Pre-service and In-service Teacher Education

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    The purposes of this paper are to develop the draft of handbook for planning, teaching and accessing the class of social studies and evaluate effects of the handbook for teacher training and their professional development. The structure of the first draft was designed based on Kolb’s learning theory. The present results suggested that the usefulness of the contents structure was perceived by (1) pre-service teachers and (2) in-service teachers, and the possibility for application was also recognized by the teacher educator as (3) university professor who teach methods courses, (4) senior supervisor who is in charge of designing the professional development programs and (5) younger supervisor who is in charge of tutoring the novice teacher, but they illustrated their different types of the significances, limits and utilization according to their purposes and as well as their responsibility. The authors implicated the alterative design of the handbook based on Korthagen’s reflective learning model for meeting their purposes and solving the structural problems inherit in the handbook

    Fundamental physics activities with pulsed neutron at J-PARC(BL05)

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    "Neutron Optics and Physics (NOP/ BL05)" at MLF in J-PARC is a beamline for studies of fundamental physics. The beamline is divided into three branches so that different experiments can be performed in parallel. These beam branches are being used to develop a variety of new projects. We are developing an experimental project to measure the neutron lifetime with total uncertainty of 1 s (0.1%). The neutron lifetime is an important parameter in elementary particle and astrophysics. Thus far, the neutron lifetime has been measured by several groups; however, different values are obtained from different measurement methods. This experiment is using a method with different sources of systematic uncertainty than measurements conducted to date. We are also developing a source of pulsed ultra-cold neutrons (UCNs) produced from a Doppler shifter are available at the unpolarized beam branch. We are developing a time focusing device for UCNs, a so called "rebuncher", which can increase UCN density from a pulsed UCN source. At the low divergence beam branch, an experiment to search an unknown intermediate force with nanometer range is performed by measuring the angular dependence of neutron scattering by noble gases. Finally the beamline is also used for the research and development of optical elements and detectors. For example, a position sensitive neutron detector that uses emulsion to achieve sub-micrometer resolution is currently under development. We have succeeded in detecting cold and ultra-cold neutrons using the emulsion detector.Comment: 9 pages, 5 figures, Proceedings of International Conference on Neutron Optics (NOP2017
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