Publications by authors named "Seiji Takeda"

106 Publications

Recent Progress Regarding the Molecular Aspects of Insect Gall Formation.

Int J Mol Sci 2021 Aug 30;22(17). Epub 2021 Aug 30.

Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Shimogamo-Hangi-cho, Sakyo-ku, Kyoto 606-8522, Japan.

Galls are characteristic plant structures formed by cell size enlargement and/or cell proliferation induced by parasitic or pathogenic organisms. Insects are a major inducer of galls, and insect galls can occur on plant leaves, stems, floral buds, flowers, fruits, or roots. Many of these exhibit unique shapes, providing shelter and nutrients to insects. To form unique gall structures, gall-inducing insects are believed to secrete certain effector molecules and hijack host developmental programs. However, the molecular mechanisms of insect gall induction and development remain largely unknown due to the difficulties associated with the study of non-model plants in the wild. Recent advances in next-generation sequencing have allowed us to determine the biological processes in non-model organisms, including gall-inducing insects and their host plants. In this review, we first summarize the adaptive significance of galls for insects and plants. Thereafter, we summarize recent progress regarding the molecular aspects of insect gall formation.
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http://dx.doi.org/10.3390/ijms22179424DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8430891PMC
August 2021

Dose Estimation of Landfill Disposal of Removed Soil Generated Outside Fukushima Prefecture.

Health Phys 2021 May;120(5):517-524

Nuclear Safety Research Center, Japan Atomic Energy Agency 2-4 Shirakara, Tokai-mura, Naka-gun, Ibaraki, Japan 319-1195.

Abstract: Dose estimation was conducted by assuming landfill disposal of removed soil generated outside the Fukushima Prefecture by each local town and in a lump sum. Because the radioactivity of removed soil is lower than that of specified waste that was generated at Fukushima Prefecture and the radioactivity concentration is 100,000 Bq kg-1 or less, simple landfill covered with 30 cm of non-contaminated soil was used. The exposure doses of loading/unloading, transportation, and landfill workers and the public residing near the repository site were estimated. Furthermore, migration of cesium into groundwater because of precipitation and using the contaminated groundwater for drinking and agricultural water was evaluated, and exposure doses regarding farmers and the ingestion of agricultural products were estimated. It was confirmed that estimated exposure doses during landfill were less than 1 mSv y-1, and those for after landfill were 0.01 mSv y-1.
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http://dx.doi.org/10.1097/HP.0000000000001371DOI Listing
May 2021

Reduction in organ-organ friction is critical for corolla elongation in morning glory.

Commun Biol 2021 03 5;4(1):285. Epub 2021 Mar 5.

Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Kyoto, Japan.

In complex structures such as flowers, organ-organ interactions are critical for morphogenesis. The corolla plays a central role in attracting pollinators: thus, its proper development is important in nature, agriculture, and horticulture. Although the intraorgan mechanism of corolla development has been studied, the importance of organ-organ interactions during development remains unknown. Here, using corolla mutants of morning glory described approximately 200 years ago, we show that glandular secretory trichomes (GSTs) regulate floral organ interactions needed for corolla morphogenesis. Defects in GST development in perianth organs result in folding of the corolla tube, and release of mechanical stress by sepal removal restores corolla elongation. Computational modeling shows that the folding occurs because of buckling caused by mechanical stress from friction at the distal side of the corolla. Our results suggest a novel function of GSTs in regulating the physical interaction of floral organs for macroscopic morphogenesis of the corolla.
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http://dx.doi.org/10.1038/s42003-021-01814-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7935917PMC
March 2021

Morphological and Genetic Diversities of (Orchidaceae) in the Kinki Area, Japan.

Int J Mol Sci 2020 Dec 30;22(1). Epub 2020 Dec 30.

Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Kyoto 606-8522, Japan.

Floral organs have evolved from leaves for reproduction, and the morphological analyses help to understand the plant diversity and evolution. (syn. ) is a terrestrial orchid living in wetlands in Japan, Russia, South Korea, and China. The habitats of this plant in Japan have been reduced because of environmental destruction and overexploitation, and thus it is on the Red List of Japan as a Near Threatened species. One of the three petals of the flower is called a lip or labellum, which resembles a flying white bird, egret, or white heron, with its proposed function being to attract pollinators. To understand the diversity of plants in different areas, we examined the lip morphology and phylogeny of populations from eight habitats in the Kinki area, Japan. The complex shapes of the lips were quantified and presented as a radar chart, enabling characterization of the morphological difference among populations. Phylogenetic analysis with microsatellite markers that we generated showed the variation of genetic diversity among populations, suggesting the different degrees of inbreeding, outbreeding, and vegetative propagation. Our approach offers a basic method to characterize the morphological and genetic diversity in natural populations.
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http://dx.doi.org/10.3390/ijms22010311DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7795838PMC
December 2020

Establishment of the Embryonic Shoot Meristem Involves Activation of Two Classes of Genes with Opposing Functions for Meristem Activities.

Int J Mol Sci 2020 Aug 15;21(16). Epub 2020 Aug 15.

Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama, Nara 630-0192, Japan.

The shoot meristem, a stem-cell-containing tissue initiated during plant embryogenesis, is responsible for continuous shoot organ production in postembryonic development. Although key regulatory factors including genes are responsible for stem cell maintenance in the shoot meristem, how the onset of such factors is regulated during embryogenesis is elusive. Here, we present evidence that the two genes and together with the two other regulatory genes and are functionally important downstream genes of and , which are a redundant pair of genes that specify the embryonic shoot organ boundary. Combined expression of with any of , , and can efficiently rescue the defects of shoot meristem formation and/or separation of cotyledons in double mutants. In addition, and are also required for the activation of , a cytochrome P450-encoding gene known to restrict organ production, and counteracts in the promotion of meristem activity, providing a possible balancing mechanism for shoot meristem maintenance. Together, these results establish the roles for and in coordinating the activation of two classes of genes with opposite effects on shoot meristem activity.
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http://dx.doi.org/10.3390/ijms21165864DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7461597PMC
August 2020

Development of an automated two pronuclei detection system on time-lapse embryo images using deep learning techniques.

Reprod Med Biol 2020 Jul 2;19(3):286-294. Epub 2020 Jun 2.

Asada Ladies Clinic Nagoya Japan.

Purpose: To establish an automated pronuclei determination system by analysis using deep learning technology which is able to effectively learn with limited amount of supervised data.

Methods: An algorithm was developed by explicitly incorporating human observation where the outline around pronuclei is being observed in determining the number of pronuclei. Supervised data were selected from the time-lapse images of 300 pronuclear stage embryos per class (total 900 embryos) clearly classified by embryologists as 0PN, 1PN, and 2PN. One-hundred embryos per class (a total of 300 embryos) were used for verification data. The verification data were evaluated for the performance of detection in the number of pronuclei by regarding the results consistent with the judgment of the embryologists as correct answers.

Results: The sensitivity rates of 0PN, 1PN, and 2PN were 99%, 82%, and 99%, respectively, and the overlapping 2PN being difficult to determine by microscopic observation alone could also be appropriately assessed.

Conclusions: This study enabled the establishment of the automated pronuclei determination system with the precision almost equivalent to highly skilled embryologists.
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http://dx.doi.org/10.1002/rmb2.12331DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7360969PMC
July 2020

Investigation on the Epoxidation of Piperitenone, and Structure-activity Relationships of Piperitenone Oxide for Differentiation-inducing Activity.

J Oleo Sci 2020 Aug 9;69(8):951-958. Epub 2020 Jul 9.

Department of Applied Biological Science, Tokyo University of Science.

Piperitenone oxide, a major chemical constituent of the essential oil of spearmint, Mentha spicata, induces differentiation in human colon cancer RCM-1 cells. In this study, piperitenone oxide and trans-piperitenone dioxide were prepared as racemic forms by epoxidation of piperitenone. The relative configuration between two epoxides in piperitenone dioxide was determined to be trans by H NMR analysis and nuclear Overhauser effect spectroscopy (NOESY) in conjunction with density functional theory (DFT) calculations. Optical resolution of (±)-piperitenone oxide by high-performance liquid chromatography (HPLC) using a chiral stationary phase (CSP) afforded both enantiomers with over 98% enantiomeric excess (ee). Evaluation of the differentiation-inducing activity of the synthetic compounds revealed that the epoxide at C-1 and C-6 in piperitenone oxide is important for the activity, and (+)-piperitenone oxide has stronger activity than (-)-piperitenone oxide. The results obtained in this study provide new information on the application of piperitenone oxide and spearmint for differentiation-inducing therapy. Furthermore, natural piperitenone oxide was isolated from M. spicata. The enantiomeric excess of the isolated natural piperitenone oxide was 66% ee. Epoxidation of piperitenone with hydrogen peroxide proceeded in a phosphate buffer under weak basic conditions to give (±)-piperitenone oxide. These results suggest that the nonenzymatic epoxidation of piperitenone, which causes a decrease in the enantiomeric excess of natural piperitenone oxide, is accompanied by an enzymatic epoxidation in the biosynthesis of piperitenone oxide.
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http://dx.doi.org/10.5650/jos.ess19278DOI Listing
August 2020

Reprogramming of the Developmental Program of During Initial Stage of Gall Induction by .

Front Plant Sci 2020 15;11:471. Epub 2020 May 15.

Laboratory of Cellular Dynamics, Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Kyoto, Japan.

Insect galls are unique organs that provide shelter and nutrients to the gall-inducing insects. Although insect galls are fascinating structures for their unique shapes and functions, the process by which gall-inducing insects induce such complex structures is not well understood. Here, we performed RNA-sequencing-based comparative transcriptomic analysis of the early developmental stage of horned gall to elucidate the early gall-inducing process carried out by the aphid, , in the Chinese sumac, . There was no clear similarity in the global gene expression profiles between the gall tissue and other tissues, and the expression profiles of various biological categories such as phytohormone metabolism and signaling, stress-response pathways, secondary metabolic pathways, photosynthetic reaction, and floral organ development were dramatically altered. Particularly, master transcription factors that regulate meristem, flower, and fruit development, and biotic and abiotic stress-responsive genes were highly upregulated, whereas the expression of genes related to photosynthesis strongly decreased in the early stage of the gall development. In addition, we found that the expression of class-1 genes, whose ectopic overexpression is known to lead to the formation of meristematic structures in leaf, was increased in the early development stage of gall tissue. These results strengthen the hypothesis that gall-inducing insects convert source tissues into fruit-like sink tissues by regulating the gene expression of host plants and demonstrate that such manipulation begins from the initial process of gall induction.
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http://dx.doi.org/10.3389/fpls.2020.00471DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7243852PMC
May 2020

DOSE ESTIMATION FOR CONTAMINATED SOIL STORAGE IN LIVING ENVIRONMENT.

Radiat Prot Dosimetry 2020 Jun;188(1):1-7

Japan Atomic Energy Agency, 2-4 Shirakata, Tokai-mura, Ibaraki 319-1195, Japan.

After the Fukushima Nuclear Power Plant accident, most of radiocesium-contaminated soil generated from decontamination activities outside Fukushima prefecture has been stored at decontamination sites such as schools, parks and residential lands (storage at sites) according to the Decontamination Guidelines. However, additional exposure due to the present storage has not been evaluated. Moreover, entering storage sites, which is not restricted for storage at sites, was not considered in safety assessment conducted in the guidelines. To continue the storage and confirm the effectiveness, understanding of present possible exposures is important. In this study, we evaluated exposure doses for residents and users of storage sites based on the present situation. As a result, annual doses due to residence were 10-2 to 10-3 mSv y-1 and doses due to annual entries were of the order of 10-3 mSv y-1. Hence, we confirmed that the exposure due to present storage outside Fukushima is significantly <1 mSv y-1.
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http://dx.doi.org/10.1093/rpd/ncz250DOI Listing
June 2020

Comparative transcriptome analysis of galls from four different host plants suggests the molecular mechanism of gall development.

PLoS One 2019 24;14(10):e0223686. Epub 2019 Oct 24.

Department of Bioresource and Environmental Sciences, Faculty of Life Sciences, Kyoto Sangyo University, Kyoto, Japan.

Galls are plant structures generated by gall-inducing organisms including insects, nematodes, fungi, bacteria and viruses. Those made by insects generally consist of inner callus-like cells surrounded by lignified hard cells, supplying both nutrients and protection to the gall insects living inside. This indicates that gall insects hijack developmental processes in host plants to generate tissues for their own use. Although galls are morphologically diverse, the molecular mechanism for their development remains poorly understood. To identify genes involved in gall development, we performed RNA-sequencing based transcriptome analysis for leaf galls. We examined the young and mature galls of Glochidion obovatum (Phyllanthaceae), induced by the micromoth Caloptilia cecidophora (Lepidoptera: Gracillariidae), the leaf gall from Eurya japonica (Pentaphylacaceae) induced by Borboryctis euryae (Lepidoptera: Gracillariidae), and the strawberry-shaped leaf gall from Artemisia montana (Asteraceae) induced by gall midge Rhopalomyia yomogicola (Oligotrophini: Cecidomyiidae). Gene ontology (GO) analyses suggested that genes related to developmental processes are up-regulated, whereas ones related to photosynthesis are down-regulated in these three galls. Comparison of transcripts in these three galls together with the gall on leaves of Rhus javanica (Anacardiaceae), induced by the aphid Schlechtendalia chinensis (Hemiptera: Aphidoidea), suggested 38 genes commonly up-regulated in galls from different plant species. GO analysis showed that peptide biosynthesis and metabolism are commonly involved in the four different galls. Our results suggest that gall development involves common processes across gall inducers and plant taxa, providing an initial step towards understanding how they manipulate host plant developmental systems.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0223686PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6812778PMC
March 2020

Substantial Narrowing on the Width of "Concentration Window" of Hydrothermal ZnO Nanowires via Ammonia Addition.

Sci Rep 2019 Oct 2;9(1):14160. Epub 2019 Oct 2.

Institute for Materials Chemistry and Engineering, Kyushu University, 6-1 Kasuga-koen, Kasuga, Fukuoka, 816-8580, Japan.

A crystal growth of hydrothermal ZnO nanowires essentially requires a concentration control within so-called "concentration window", where the anisotropic crystal growth of ZnO nanowires preferentially occurs. Although understanding what exactly determines the width of "concentration window" is important to tailor the anisotropic crystal growth process, the fundamental knowledge as to "concentration window" is still scarce. Here we report the effect of ammonia addition on the width of "concentration window" using conventional hydrothermal ZnO nanowire growth. We found that the ammonia addition substantially narrows the width of "concentration window". Within the narrow range of zinc complex concentration, we found a significant increase of growth rate (up to 2000 nm/h) of ZnO nanowires. The narrowed "concentration window" and the resultant increased growth rate by the ammonia addition can be understood in terms of synchronized effects of both (1) a reduction of zinc hydroxide complex (precursor) concentration and (2) a fast rate limiting process of ligand exchange between different zinc complexes. Thus, the present knowldege as to "concentration window" will accelerate further tailoring an anisotropic crystal growth of hydrothermal ZnO nanowires.
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http://dx.doi.org/10.1038/s41598-019-50641-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6775099PMC
October 2019

Visualizing Progressive Atomic Change in the Metal Surface Structure Made by Ultrafast Electronic Interactions in an Ambient Environment.

Angew Chem Int Ed Engl 2019 Nov 24;58(45):16028-16032. Epub 2019 Sep 24.

The Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka, 567-0047, Japan.

Understanding the atomic and molecular phenomena occurring in working catalysts and nanodevices requires the elucidation of atomic migration originating from electronic excitations. The progressive atomic dynamics on metal surface under controlled electronic stimulus in real time, space, and gas environments are visualized for the first time. By in situ environmental transmission electron microscopy, the gas molecules introduced into the biased metal nanogap could be activated by electron tunneling and caused the unpredicted atomic dynamics. The typically inactive gold was oxidized locally on the positive tip and field-evaporated to the negative tip, resulting in the atomic reconstruction on the negative tip surface. This finding of a tunneling-electron-attached-gas process will bring new insights into the design of nanostructures such as nanoparticle catalysts and quantum nanodots and will stimulate syntheses of novel nanomaterials not seen in the ambient environment.
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http://dx.doi.org/10.1002/anie.201907679DOI Listing
November 2019

DEVElOPMENT OF DOSE ESTIMATION SYSTEM INTEGRATING SEDIMENT MODEL FOR RECYCLING RADIOCESIUM-CONTAMINATED SOIL TO COASTAL RECLAMATION.

Radiat Prot Dosimetry 2019 Oct;184(3-4):372-375

The University of Tokyo, Chiba, Japan.

We have developed a dose estimation system integrating assessment methods of radionuclide dispersion in ocean for the case of recycling radiocesium-contaminated soil to coastal reclamation. Radionuclide dispersion in ocean is assessed considering dissolved radionuclide and adsorbed radionuclide on particle by sediment model (OECD/NEA). Time series of Cs-137 dispersion at Fukushima coastal area is assessed by the sediment model and result is almost same with measured value. The major exposure pathways in recycling are estimated by using result of radiocesium dispersion assessment, and internal exposure dose by marine products ingestion is sufficiently lower than external exposure dose of worker.
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http://dx.doi.org/10.1093/rpd/ncz128DOI Listing
October 2019

Origin of gall-inducing from leaf-mining in Caloptilia micromoths (Lepidoptera, Gracillariidae).

Sci Rep 2019 05 1;9(1):6794. Epub 2019 May 1.

Institut de Recherche sur la Biologie de l'Insecte, UMR 7261, CNRS/Université de Tours, UFR Sciences et Techniques, Tours, France.

In insects, the gall-inducing life-style has evolved independently many times. Several evolutionary pathways leading to this lifestyle have been proposed. While there is compelling evidence supporting surface-feeders and stem-borers as ancestral states of insect gall-inducers, an evolutionary pathway from leaf-miners remains hypothetical. Here we explored this question by comparing the developmental processes of two micromoths, a gall-inducer Caloptilia cecidophora (Lep., Gracillariidae), and its non-gall-inducing relative C. ryukyuensis. Like other Caloptilia, the first and second instars of C. cecidophora are leaf-miners and the gall is initiated inside the leaf mine by the third instar, thus suggesting leaf-mining as an ancestral, plesiomorphic state in this case. This is the first example of an insect species switching from leaf-mining to gall-inducing during larval development. The first two leaf-mining instars of C. cecidophora exhibit an absence of growth and a reduced time duration compared to C. ryukyuensis. The shortening of the duration of leaf-mining stages is apparently compensated in C. cecidophora by a larger egg size than C. ryukyuensis, and an additional larval instar during the gall phase.
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http://dx.doi.org/10.1038/s41598-019-43213-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6494848PMC
May 2019

Reversible gas-solid reaction in an electronically-stimulated palladium nanogap.

Nanoscale 2019 May;11(18):8715-8717

The Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan.

We investigated a nanogap between a pair of palladium electrode tips with gas (nitrogen, hydrogen, and oxygen) and a biasing voltage using in situ atomic resolution environmental transmission electron microscopy (ETEM). We found an unexpected gas-solid (nitrogen-palladium) reaction that occurs on the surface of the positive electrode tip. A palladium nitride compound was synthesized with gaseous nitrogen at low pressure at room temperature. The nitridation of palladium was previously reported and predicted to occur only under high pressure and at high temperature. The reaction in ETEM apparatus was reversible with the change in the magnitude of an electric field in the nanogap. Additionally, the asymmetrical surface dynamics on the pair of electrode tips in gas (nitrogen, hydrogen, and oxygen) were revealed by ETEM observation. It is likely that the electrons in the gap induce the reversible reaction. This study has opened a new route toward creating nanoscale materials because the creation, stabilization, and annihilation of the material in a nanogap can be controlled electrically and electronically on demand for various applications.
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http://dx.doi.org/10.1039/c9nr00806cDOI Listing
May 2019

Recent advances in physical reservoir computing: A review.

Neural Netw 2019 Jul 20;115:100-123. Epub 2019 Mar 20.

Institute for Innovation in International Engineering Education, Graduate School of Engineering, The University of Tokyo, Tokyo 113-8656, Japan; Department of Electrical Engineering and Information Systems, Graduate School of Engineering, The University of Tokyo, Tokyo 113-8656, Japan.

Reservoir computing is a computational framework suited for temporal/sequential data processing. It is derived from several recurrent neural network models, including echo state networks and liquid state machines. A reservoir computing system consists of a reservoir for mapping inputs into a high-dimensional space and a readout for pattern analysis from the high-dimensional states in the reservoir. The reservoir is fixed and only the readout is trained with a simple method such as linear regression and classification. Thus, the major advantage of reservoir computing compared to other recurrent neural networks is fast learning, resulting in low training cost. Another advantage is that the reservoir without adaptive updating is amenable to hardware implementation using a variety of physical systems, substrates, and devices. In fact, such physical reservoir computing has attracted increasing attention in diverse fields of research. The purpose of this review is to provide an overview of recent advances in physical reservoir computing by classifying them according to the type of the reservoir. We discuss the current issues and perspectives related to physical reservoir computing, in order to further expand its practical applications and develop next-generation machine learning systems.
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http://dx.doi.org/10.1016/j.neunet.2019.03.005DOI Listing
July 2019

Interaction between LDL-mimetic liposomes and acid-treated carbon nanotube electrode during Cu-mediated oxidation.

Biochem Biophys Res Commun 2019 05 3;513(1):275-279. Epub 2019 Apr 3.

Department of Nutrition, Sapporo University of Health Sciences, Sapporo, 007-0894, Japan.

Oxidation of low-density lipoproteins (LDL) causes atherosclerosis. Detection of oxidation of LDL-mimetic liposomes using an electrode might serve as a convenient tool in the search of antioxidants for the prevention of atherosclerosis. This report proposes a reaction mechanism between LDL-mimetic liposomes and an acid-treated carbon nanotube (CNT) electrode. Oxidation of the liposomes, mediated by Cu, was monitored by the change in electrode potential, and the fluorescence intensity generated by diphenyl-1-pyrenylphosphine (DPPP) as control. The electrode potential and fluorescence intensity increased concomitantly during oxidation, followed by a gradual decrease. Although the electrical potential peaked faster than the fluorescence intensity, addition of CNT to the DPPP reaction accelerated the latter, suggesting the role of CNT as an accelerator of liposome oxidation. Atomic force microscopy showed increased binding of liposomes to CNT along with liposomal deformation. Further, binding of Cu to the liposome-bound CNT surface was observed by quartz crystal microbalance. In conclusion, the interaction of liposomes with Cu and CNT surface explains the rapid response of the electrode in liposome oxidation.
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http://dx.doi.org/10.1016/j.bbrc.2019.03.106DOI Listing
May 2019

Author Correction: PtdIns(3,5)P mediates root hair shank hardening in Arabidopsis.

Nat Plants 2019 Apr;5(4):447

Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Kyoto, Japan.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.
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http://dx.doi.org/10.1038/s41477-019-0416-xDOI Listing
April 2019

Rational Method of Monitoring Molecular Transformations on Metal-Oxide Nanowire Surfaces.

Nano Lett 2019 04 26;19(4):2443-2449. Epub 2019 Mar 26.

Interdisciplinary Graduate School of Engineering Sciences , Kyushu University , 6-1 Kasuga-Koen , Kasuga , Fukuoka 816-8580 , Japan.

Metal-oxide nanowires have demonstrated excellent capability in the electrical detection of various molecules based on their material robustness in liquid and air environments. Although the surface structure of the nanowires essentially determines their interaction with adsorbed molecules, understanding the correlation between an oxide nanowire surface and an adsorbed molecule is still a major challenge. Herein, we propose a rational methodology to obtain this information for low-density molecules adsorbed on metal oxide nanowire surfaces by employing infrared p-polarized multiple-angle incidence resolution spectroscopy and temperature-programmed desorption/gas chromatography-mass spectrometry. As a model system, we studied the surface chemical transformation of an aldehyde (nonanal, a cancer biomarker in breath) on single-crystalline ZnO nanowires. We found that a slight surface reconstruction, induced by the thermal pretreatment, determines the surface chemical reactivity of nonanal. The present results show that the observed surface reaction trend can be interpreted in terms of the density of Zn ions exposed on the nanowire surface and of their corresponding spatial arrangement on the surface, which promotes the reaction between neighboring adsorbed molecules. The proposed methodology will support a better understanding of complex molecular transformations on various nanostructured metal-oxide surfaces.
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http://dx.doi.org/10.1021/acs.nanolett.8b05180DOI Listing
April 2019

Inside the horn of plenty: Leaf-mining micromoth manipulates its host plant to obtain unending food provisioning.

PLoS One 2018 21;13(12):e0209485. Epub 2018 Dec 21.

Department of Life and Environmental Sciences, Kyoto Prefectural University, Kyoto, Japan.

Leaves represent the main resource for herbivorous insects and their performances are mainly a function of leaf nutritional quality. Two feeding strategies are known to optimize the exploitation of leaf resources: leaf-miners that selectively feed on tissues of high nutritional quality and gall-inducers that induce the development of a new tissue showing an enhanced nutritional value. Some leaf-miners are known to also manipulate their nutritional environment, but do not affect plant development. Cases of callus proliferation in leaf-mines have been reported, however, the direct role of the insect in the formation of additional plant cells and the nutritional function of this tissue have never been established. Using an experimental approach, we show that leaf-mining larvae of micromoth, Borboryctis euryae (Lepidoptera: Gracillariidae), that grow on Eurya japonica (Pentaphylacaceae), actively induce callus proliferation within their leaf-mine at the fourth instar. We experimentally demonstrated that, at this developmental stage, the larva feeds exclusively on this newly formed tissue and feeding of the tissue is essential for completing larval stage. Phenological census revealed considerable expansion and variation of fourth instar duration caused by the continuous production of callus. We propose here the "cornucopia" hypothesis which states that the newly produced callus induced by the leaf-mining larvae provides virtually unending nourishment, which in turn allows flexible larval development time. This represents the first example of a leaf-miner manipulating plant development to its benefit, like a gall-inducer. We propose to name this life style "mine-galler".
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0209485PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6303051PMC
June 2019

Comparative analysis of the reactive oxygen species-producing enzymatic activity of Arabidopsis NADPH oxidases.

Plant J 2019 04 14;98(2):291-300. Epub 2019 Feb 14.

Department of Applied Biological Science, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba, 278-8510, Japan.

Reactive oxygen species (ROS) produced by NADPH oxidases, called respiratory burst oxidase homologs (Rbohs), play crucial roles in development as well as biotic and abiotic stress responses in plants. Arabidopsis has 10 Rboh genes, AtRbohA to AtRbohJ. Five AtRbohs (AtRbohC, -D, -F, -H and -J) are synergistically activated by Ca -binding and protein phosphorylation to produce ROS that play various roles in planta, although the activities of the other Rbohs remain unknown. With a heterologous expression system, we found a range of ROS-producing activity among the AtRbohs with differences up to 100 times, indicating that the required amounts of ROS are different in each situation where AtRbohs act. To specify the functions of AtRbohs involved in cell growth, we focused on AtRbohC, -H and -J, which are involved in tip growth of root hairs or pollen tubes. Ectopic expression of the root hair factor AtRbohC/ROOT HAIR DEFECTIVE 2 (RHD2) in pollen tubes restored the atrbohH atrbohJ defects in tip growth of pollen tubes. However, expression of AtRbohH or -J in root hairs did not complement the tip growth defect in the atrbohC/rhd2 mutant. Our data indicate that Rbohs possess different ranges of enzymatic activity, and that some Rbohs have evolved to carry specific functions in cell growth.
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http://dx.doi.org/10.1111/tpj.14212DOI Listing
April 2019

Abscisic acid-mediated developmental flexibility of stigmatic papillae in response to ambient humidity in Arabidopsis thaliana.

Genes Genet Syst 2018 Dec 24;93(5):209-220. Epub 2018 Nov 24.

Laboratory of Molecular Genetics and Breeding, Graduate School of Bioresources, Mie University.

Stigmatic papillae develop at the apex of the gynoecium and play an important role as a site of pollination. The papillae in Brassicaceae are of the dry and unicellular type, and more than 15,000 genes are expressed in the papillae; however, the molecular and physiological mechanisms of their development remain unknown. We found that the papillae in Arabidopsis thaliana change their length in response to altered ambient humidity: papillae of flowers incubated under high humidity elongated more than those under normal humidity conditions. Genetic analysis and transcriptome data suggest that an abscisic acid-mediated abiotic stress response mechanism regulates papilla length. Our data suggest a flexible regulation of papilla elongation at the post-anthesis stage, in response to abiotic stress, as an adaptation to environmental conditions.
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http://dx.doi.org/10.1266/ggs.18-00025DOI Listing
December 2018

PtdIns(3,5)P mediates root hair shank hardening in Arabidopsis.

Nat Plants 2018 11 2;4(11):888-897. Epub 2018 Nov 2.

Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Kyoto, Japan.

Root hairs elongate by tip growth and simultaneously harden the shank by constructing the inner secondary cell wall layer. While much is known about the process of tip growth, almost nothing is known about the mechanism by which root hairs harden the shank. Here we show that phosphatidylinositol-3,5-bisphosphate (PtdIns(3,5)P), the enzymatic product of FORMATION OF APLOID AND BINUCLEATE CELLS 1 (FAB1), is involved in the hardening of the shank in root hairs in Arabidopsis. FAB1 and PtdIns(3,5)P localize to the plasma membrane along the shank of growing root hairs. By contrast, phosphatidylinositol 4-phosphate 5-kinase 3 (PIP5K3) and PtdIns(4,5)P localize to the apex of the root hair where they are required for tip growth. Reduction of FAB1 function results in the formation of wavy root hairs while those of the wild type are straight. The localization of FAB1 in the plasma membrane of the root hair shank requires the activity of Rho-related GTPases from plants 10 (ROP10) and localization of ROP10 requires FAB1 activity. Computational modelling of root hair morphogenesis successfully reproduces the wavy root hair phenotype. Taken together, these data demonstrate that root hair shank hardening requires PtdIns(3,5)P/ROP10 signalling.
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http://dx.doi.org/10.1038/s41477-018-0277-8DOI Listing
November 2018

Life Cycle and Genetic Diversity of (Araceae), an Endangered Species in Japan.

Plants (Basel) 2018 Sep 11;7(3). Epub 2018 Sep 11.

Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Hangi-cho 1-5, Shimogamo, Sakyo-ku, Kyoto 606-8522, Japan.

, a member of the Araceae family, is an endangered plant in several prefectures in Japan. For the conservation of this wild species, we investigated the morphology, life cycle, and genetic diversity of three wild populations. By fixed-point observation over several years, we found that it takes at least four years for the plant to set the inflorescences consisting of spadices and spathes, and another two years for it to set mature seeds. To examine the genetic diversity in the wild population, we developed 11 novel microsatellite markers and investigated the genetic variation in three populations in Kyoto Prefecture: Ayabe, Hanase, and Momoi. The Ayabe population carried less genetic variation than the other two areas, suggesting the isolation of the habitat and thus a higher risk of extinction. Our results provide basic knowledge of the ecological aspects of , as well as molecular techniques for the assessment of its genetic diversity, and thus are useful for the conservation of this endangered species.
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http://dx.doi.org/10.3390/plants7030073DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6161092PMC
September 2018

Dose Estimation in Recycling of Decontamination Soil Resulting From The Fukushima NPS Accident For Road Embankments.

Health Phys 2018 10;115(4):439-447

Nuclear Safety Research Center, Japan Atomic Energy Agency, 2-4 Shirakata, Tokai-mura, Naka-gun, Ibaraki 319-1195, Japan.

Since the Fukushima nuclear power station accident, large quantities of radiocesium-contaminated soil generated from decontamination activities have been stored in Fukushima prefecture. To complete the final disposal of decontamination soil, reducing the disposal volume through recycling can prove effective. The Ministry of the Environment of Japan has developed a policy of handling low-activity decontamination soil as recycled materials under the management of public authority. The recycling is limited to civil engineering structures in public projects, such as road embankments and coastal levees. However, there has been no practical review or safety assessment of decontamination soil recycling. In this study, to contribute to guideline development for decontamination soil recycling by the Ministry of the Environment, dose estimation was considered as a way of ensuring that the use of recycled decontamination soil for road embankments was safe. First, based on Japanese construction standards, additional doses to workers and the public in construction and service (e.g., use of a road embankment) scenarios were evaluated. From the result, the radioactive cesium concentration level of recycled materials that would result in all additional doses meeting the radiation criterion of 1 mSv y was derived to be 6,000 Bq kg. Then, construction conditions were reviewed to reduce additional doses to the public in a service scenario. To confine doses to the public to below 10 μSv y based on the derived radioactivity level, an additional layer of soil slope protection of 40 cm or more was needed. Finally, additional doses expected in a disaster scenario were confirmed to be below 1 mSv y based on the derived radioactivity level, an additional layer of soil slope protection of 40 cm or more was needed. Finally, additional doses expected in a disaster scenario were confirmed to be below 1 mSv y based on the derived radioactivity level.
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http://dx.doi.org/10.1097/HP.0000000000000904DOI Listing
October 2018

Examining the effect of regioisomerism on the physico-chemical properties of lysophosphatidylethanolamine-containing liposomes using fluoro probes.

Chem Phys Lipids 2018 11 3;216:9-16. Epub 2018 Aug 3.

Graduate School of Health Science, Hokkaido University, North 12, West 5, Kita-ku, Sapporo, 060-0812 Japan. Electronic address:

Lysophospholipids (LysoPLs) receive steadily increasing attention in the area of lipid chemistry and biology. However, the physico-chemical properties of individual LysoPL regioisomers have not yet been investigated. Herein, we report the synthesis of fluoro analogues of lysophosphatidylethanolamines (LPEs) and examine the physico-chemical properties of the LPE regioisomers using chemically synthesized fluoro probes.
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http://dx.doi.org/10.1016/j.chemphyslip.2018.08.001DOI Listing
November 2018

Impact of the electron beam on the thermal stability of gold nanorods studied by environmental transmission electron microscopy.

Ultramicroscopy 2018 10 18;193:97-103. Epub 2018 Jun 18.

The Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan. Electronic address:

In-situ transmission electron microscopy experiments are of great interest to nanoscience and nanotechnology. However, it is known that the electron beam can have a significant impact on the structure of the sample which makes it important to carefully interpret in-situ data. In this work, we studied the thermal stability of CTAB-stabilized gold nanorods under different gaseous environments in an environmental transmission electron microscope and compared the outcome to ex-situ heating experiments. We observed a remarkable influence of the electron beam: While the nanorods were stable under inert conditions when exposed to the electron beam even at 400°C, the same nanorods reshaped at temperatures as low as 100°C under ex-situ conditions. We ascribe the stabilizing effect to the transformation of the CTAB bi-layer into a thin carbon layer under electron beam irradiation, preventing the nanorods from deforming. When exposed to an oxidizing environment in the environmental transmission electron microscope, this carbon layer was gradually removed and the gold atoms became mobile allowing for the deformation of the rod. This work highlights the importance of understanding the phenomena taking place under electron beam irradiation, which can greatly affect in-situ experiments and conclusions drawn from these. It stresses that in-situ electron microscopy data, taken on measuring the temperature dependence of nanoparticle properties, should be carefully assessed and accompanied by ex-situ experiments if possible.
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http://dx.doi.org/10.1016/j.ultramic.2018.05.006DOI Listing
October 2018

Self-activated surface dynamics in gold catalysts under reaction environments.

Nat Commun 2018 05 25;9(1):2060. Epub 2018 May 25.

The Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka, 567-0047, Japan.

Nanoporous gold (NPG) with sponge-like structures has been studied by atomic-scale and microsecond-resolution environmental transmission electron microscopy (ETEM) combined with ab initio energy calculations. Peculiar surface dynamics were found in the reaction environment for the oxidation of CO at room temperature, involving residual silver in the NPG leaves as well as gold and oxygen atoms, especially on {110} facets. The NPG is thus classified as a novel self-activating catalyst. The essential structure unit for catalytic activity was identified as Au-AgO surface clusters, implying that the NPG is regarded as a nano-structured silver oxide catalyst supported on the matrix of NPG, or an inverse catalyst of a supported gold nanoparticulate (AuNP) catalyst. Hence, the catalytically active structure in the gold catalysts (supported AuNP and NPG catalysts) can now be experimentally unified in low-temperature CO oxidation, a step forward towards elucidating the fascinating catalysis mechanism of gold.
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http://dx.doi.org/10.1038/s41467-018-04412-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5970267PMC
May 2018

Effects of enzymes on elastic modulus of low-density lipoproteins were investigated using atomic force microscopy.

Biochem Biophys Res Commun 2018 06;501(3):607-611

Faculty of Health Science, Sapporo University of Health Sciences, 007-0894, Japan.

Oxidation of low-density lipoproteins (LDLs) induces development of cardiovascular disease. Recently, reports of studies using atomic force microscopy (AFM) have described that the elastic modulus of metal-induced oxidized LDLs is lower than the modulus before oxidation. However, the mechanisms of change of the elastic modulus have not been well investigated. We postulated that disorder of the LDL structure might decrease the elastic modulus. This study measured the elastic modulus of LDLs before and after enzyme treatment with V8 protease, α-chymotrypsin, and phospholipase A. After LDLs were obtained from serum by ultracentrifugation, LDLs or enzyme-treated LDLs were physically absorbed. They were crowded on a mica surface. Although V8 protease and α-chymotrypsin did not induce the elastic modulus change, treatment with PLA decreased the elastic modulus. The LDL particle size did not change during the enzyme treatment. Results suggest that disordering of the lipid structure of the LDL might contribute to the elastic modulus change. Results show that AFM might be a useful tool to evaluate disorders of complex nanoscale particle structures from lipids and proteins such as lipoproteins.
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http://dx.doi.org/10.1016/j.bbrc.2018.04.211DOI Listing
June 2018

An Efficient Glycoblotting-Based Analysis of Oxidized Lipids in Liposomes and a Lipoprotein.

Chembiochem 2017 10 23;18(19):1903-1909. Epub 2017 Aug 23.

Graduate School of Health Science, Hokkaido University, N12 W5, Kita-ku, Sapporo, 0600812, Japan.

Although widely occurring lipid oxidation, which is triggered by reactive oxygen species (ROS), produces a variety of oxidized lipids, practical methods to efficiently analyze oxidized lipids remain elusive. Herein, it is shown that the glycoblotting platform can be used to analyze oxidized lipids. Analysis is based on the principle that lipid aldehydes, one of the oxidized lipid species, can be captured selectively, enriched, and detected. Moreover, 3-methyl-1-p-tolyltriazene (MTT) methylates phosphoric and carboxylic acids, and this MTT-mediated methylation is, in combination with conventional tandem mass spectrometry (MS/MS) analysis, an effective method for the structural analysis of oxidized lipids. By using three classes of standards, liposomes, and a lipoprotein, it is demonstrated that glycoblotting represents a powerful approach for focused lipidomics, even in complex macromolecules.
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http://dx.doi.org/10.1002/cbic.201700384DOI Listing
October 2017
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