年輪を持たない熱帯樹木の年輪代替物としての酸素安定同位体の検討

京都大学0048新制・課程博士博士(農学)甲第21971号農博第2361号新制||農||1071(附属図書館)学位論文||R1||N5222(農学部図書室)京都大学大学院農学研究科森林科学専攻(主査)教授 大澤 晃, 教授 髙部 圭司, 教授 小杉 緑子学位規則第4条第1項該当Doctor of Agricultural ScienceKyoto UniversityDGA

Radial and vertical distributions of radiocesium in tree stems of Pinus densiflora and Quercus serrata 1.5 y after the Fukushima nuclear disaster.

The radial and vertical distributions of radiocesium in tree stems were investigated to understand radiocesium transfer to trees at an early stage of massive contamination from the Fukushima nuclear disaster. A conifer species (Japanese red pine) and a broad-leaved species (Japanese konara oak) were selected to determine whether the radiocesium contamination pattern differs between species. Stem disks were collected at several heights and separated into outer bark, inner bark, and wood. The radiocesium concentration was the highest in the outer bark, followed by that in the inner bark and wood. The vertical distribution of the radiocesium concentration at each stem part differed between the species. The difference between species in radiocesium concentration of the outer bark could be explained by presence or absence of leaves at the time of the disaster. However, the reasons for the differences between species in the radiocesium concentration of the inner bark and wood are unclear. The radial distribution in the wood of the studied species showed a common pattern across stem disk heights and species. However, the radiocesium concentration ratio between sapwood and inner bark was significantly different between species. Although the radial contamination pattern in the wood was similar in the studied species during the early stage of contamination, the radiocesium transport pathway and allocation would be different between the species, and the contamination pattern will likely be different between the species at later stages. Continued investigations are important for understanding the radiocesium cycle and the accumulation of radiocesium in the tree stems of each species

Preferential {100} etching of boron-doped diamond electrodes and diamond particles by CO2 activation

The etching behavior of polycrystalline boron-doped diamond (BDD) electrodes and diamond particles with gaseous CO2 at 800 and 900 degrees C was investigated by field-emission scanning electron microscopy, atomic force microscopy and X-ray photoelectron spectroscopy. Polycrystalline BDD (800 ppm), composed of a mixture of cubic {100} and triangular {111} orientated planes, was used so as to pursue the possibility of preferential etching by high temperature CO2 treatment. Nanometer sized pits were observed on the {100} planes while no change was observable for the {111} planes when the activation temperature was 800 degrees C. The difference in the etching behavior by CO2 with regard to the different planes was clarified using diamond particles and comparing with steam activation. The results demonstrate that CO2 activation leads to preferential {100} etching, whereas steam-activation results in preferential {111} etching.ArticleCARBON. 70:207-214 (2014)journal articl

Positive and negative regulation of the Fcγ receptor–stimulating activity of RNA-containing immune complexes by RNase

The U1RNP complex, Ro/SSA, and La/SSB are major RNA-containing autoantigens. Immune complexes (ICs) composed of RNA-containing autoantigens and autoantibodies are suspected to be involved in the pathogenesis of some systemic autoimmune diseases. Therefore, RNase treatment, which degrades RNA in ICs, has been tested in clinical trials as a potential therapeutic agent. However, no studies to our knowledge have specifically evaluated the effect of RNase treatment on the Fcγ receptor–stimulating (FcγR-stimulating) activity of RNA-containing ICs. In this study, using a reporter system that specifically detects FcγR-stimulating capacity, we investigated the effect of RNase treatment on the FcγR-stimulating activity of RNA-containing ICs composed of autoantigens and autoantibodies from patients with systemic autoimmune diseases such as systemic lupus erythematosus. We found that RNase enhanced the FcγR-stimulating activity of Ro/SSA- and La/SSB-containing ICs, but attenuated that of the U1RNP complex–containing ICs. RNase decreased autoantibody binding to the U1RNP complex, but increased autoantibody binding to Ro/SSA and La/SSB. Our results suggest that RNase enhances FcγR activation by promoting the formation of ICs containing Ro/SSA or La/SSB. Our study provides insights into the pathophysiology of autoimmune diseases involving anti-Ro/SSA and anti-La/SSB autoantibodies, and into the therapeutic application of RNase treatment for systemic autoimmune diseases.Naito R., Ohmura K., Higuchi S., et al. Positive and negative regulation of the Fcγ receptor–stimulating activity of RNA-containing immune complexes by RNase. JCI Insight 8, e167799 (2023); https://doi.org/10.1172/jci.insight.167799

Chromosome integrity at a double-strand break requires exonuclease 1 and MRX

The continuity of duplex DNA is generally considered a prerequisite for chromosome continuity. However, as previously shown in yeast as well as human cells, the introduction of a double-strand break (DSB) does not generate a chromosome break (CRB) in yeast or human cells. The transition from DSB to CRB was found to be under limited control by the tethering function of the RAD50/MRE11/XRS2 (MRX) complex. Using a system for differential fluorescent marking of both sides of an endonuclease-induced DSB in single cells, we found that nearly all DSBs are converted to CRBs in cells lacking both exonuclease 1 (EXO1) activity and MRX complex. Thus, it appears that some feature of exonuclease processing or resection at a DSB is critical for maintaining broken chromosome ends in close proximity. In addition, we discovered a thermal sensitive (cold) component to CRB formation in an MRX mutant that has implications for chromosome end mobility and/or end-processing

Comparison of Bacterial Flora in a Methane Fermentation Plant in Field Science Center at Tohoku University and Bovine Rumen Used as the Plant Microbial Resource by 16S rRNA Gene Sequencing

Poster Sessio

A Study on Novice Teachers’ Development of Practical Qualities and Competencies : Through comparison between novices, 2nd years, 6th years, and mentors

This study compares and examines between consciousness of teachers with different length of teaching about professional development of practical qualities and competencies: 61 novices; 63 teachers with two years teaching experience; 67 teachers with six years teaching experience; 78 mentors. As a result of our examination, we reached following three conclusions: 1) The stably-required practical qualities and competencies have three factors structure and the temporarily-overrated ones have two factors structure. 2) Teachers consider increasingly that the basic competencies of learning instruction, designing children-centered lessons and general educational activities less need to be acquired by novices in a rushed way during their initial stages instead teachers need to acquire them gradually after those stages in association with the length of teaching experience. 3) Teachers tend to give a higher estimate how much novices acquire those competencies with increasing teaching experience and they might consider that they had already learned all basics during their initial stages; including the practical qualities and competencies they actually have acquired in their teaching years

A consortium study of Antarctic micrometeorites recovered from the Dome Fuji Station

Deposits in the water tank at the Dome Fuji Station were collected by the 37th Japanese Antarctic Research Expedition team in 1996. We recovered 233 micrometeorites from the deposits. A consortium study was started in late 1998 to investigate mineralogy, petrology, bulk chemistry, and isotopic compositions of the micrometeorites. This is the first case of an organized study of micrometeorites in Japan, in order to establish the methods to investigate micrometeorites routinely. Consortium results on mineralogy, petrology, minor and trace element compositions, isotopic compositions of noble gases of the micrometeorites are reported in this volume. We also found a sequence of mineralogical and compositional changes of micrometeorites experienced from frictional heating during atmospheric entry. INAA and ion probe studies are now in progress