Photoreduction and Reoxidation of the Three Iron-Sulfur Clusters of Reaction Centers of Green Sulfur Bacteria

AbstractIron-sulfur clusters are the terminal electron acceptors of the photosynthetic reaction centers of green sulfur bacteria and photosystem I. We have studied electron-transfer reactions involving these clusters in the green sulfur bacterium Chlorobium tepidum, using flash-absorption spectroscopic measurements. We show for the first time that three different clusters, named FX, F1, and F2, can be photoreduced at room temperature during a series of consecutive flashes. The rates of electron escape to exogenous acceptors depend strongly upon the number of reduced clusters. When two or three clusters are reduced, the escape is biphasic, with the fastest phase being 12–14-fold faster than the slowest phase, which is similar to that observed after single reduction. This is explained by assuming that escape involves mostly the second reducible cluster. Evidence is thus provided for a functional asymmetry between the two terminal acceptors F1 and F2. From multiple-flash experiments, it was possible to derive the intrinsic recombination rates between P840+ and reduced iron-sulfur clusters: values of 7, 14, and 59s−1 were found after one, two and three electron reduction of the clusters, respectively. The implications of our results for the relative redox potentials of the three clusters are discussed

Application of the Hope Theory to Understand Reconstruction Beliefs and Life Satisfaction Level among Residents following the Fukushima Disaster

The Great Eastern Japan Earthquake struck in 2011, which had an enormous impact on society and lives in the northern part of the Japan (Tohoku region). The disaster also led to hydrogen explosion at the Fukushima Daiichi Nuclear Plant (FDNP), resulting in leakage of radioactive substances that contaminated the surrounding area. The Fukushima population is highly stressed and lives under constant fear of radiation, in addition to losing neighbors to evacuations during the earthquakes and the tsunami. Yet, there is lack of research on the psychological state of Japanese earthquake survivors. The present study uses psychological variables to measure hope for understanding how these factors could explain beliefs toward reconstruction and life satisfaction level of the local residents in Miyakoji town of Fukushima Prefecture. The survey (n=223) showed that only a few residents (about 30%) believed in successful reconstruction. Regression analysis revealed that factors of hope such as pathway and agency thinking have an influence on respondents’ beliefs regarding reconstruction and their level of life satisfaction. Future outreach and supporting activities should target raising residents’ hope to increase their psychological well-being

Morphology and release kinetics of protein-loaded porous poly(L-lactic acid) spheres prepared by freeze-drying technique

Freeze-drying a biodegradable polymer, poly(L-lactic acid) (PLLA) from 1,4-dioxane solutions provided very porous spherical particles of ca. 3 mm in radius with specific surface area of 8 − 13 m2 g−1. The surface of the particle was found to be less porous compared with its interior. To apply the freeze-dried PLLA (FDPLLA) to drug delivery system, its morphology and drug releasing kinetics were investigated, bovine serum albumin (BSA) being used as a model drug compound. Immersion of FDPLLA into a BSA aqueous solution gave BSA-loaded FDPLLA, where mass fraction of the adsorbed BSA reached up to 79%. Time-dependent release profile of BSA in water suggested a two-step mechanism: (1) very rapid release of BSA deposited on and near the particle surface, which results in an initial burst, and (2) leaching of BSA from the interior of the particle by the diffusion process. It was suggested that the latter process is largely governed by the surface porosity. The porosity of both the interior and surface was found to decrease remarkably as the concentration of the original PLLA / 1,4-dioxane solution increases, C0. Thus, C0 is a key parameter that controls the loading and releasing of BSA

TriMEDB: A database to integrate transcribed markers and facilitate genetic studies of the tribe Triticeae

<p>Abstract</p> <p>Background</p> <p>The recent rapid accumulation of sequence resources of various crop species ensures an improvement in the genetics approach, including quantitative trait loci (QTL) analysis as well as the holistic population analysis and association mapping of natural variations. Because the tribe Triticeae includes important cereals such as wheat and barley, integration of information on the genetic markers in these crops should effectively accelerate map-based genetic studies on Triticeae species and lead to the discovery of key loci involved in plant productivity, which can contribute to sustainable food production. Therefore, informatics applications and a semantic knowledgebase of genome-wide markers are required for the integration of information on and further development of genetic markers in wheat and barley in order to advance conventional marker-assisted genetic analyses and population genomics of Triticeae species.</p> <p>Description</p> <p>The Triticeae mapped expressed sequence tag (EST) database (TriMEDB) provides information, along with various annotations, regarding mapped cDNA markers that are related to barley and their homologues in wheat. The current version of TriMEDB provides map-location data for barley and wheat ESTs that were retrieved from 3 published barley linkage maps (the barley single nucleotide polymorphism database of the Scottish Crop Research Institute, the barley transcript map of Leibniz Institute of Plant Genetics and Crop Plant Research, and HarvEST barley ver. 1.63) and 1 diploid wheat map. These data were imported to CMap to allow the visualization of the map positions of the ESTs and interrelationships of these ESTs with public gene models and representative cDNA sequences. The retrieved cDNA sequences corresponding to each EST marker were assigned to the rice genome to predict an exon-intron structure. Furthermore, to generate a unique set of EST markers in Triticeae plants among the public domain, 3472 markers were assembled to form 2737 unique marker groups as contigs. These contigs were applied for pairwise comparison among linkage maps obtained from different EST map resources.</p> <p>Conclusion</p> <p>TriMEDB provides information regarding transcribed genetic markers and functions as a semantic knowledgebase offering an informatics facility for the acceleration of QTL analysis and for population genetics studies of Triticeae.</p

Detection of abnormal myocardial deformation during acute myocardial ischemia using three-dimensional speckle tracking echocardiography

Background: Three-dimensional (3D) speckle tracking echocardiography can simultaneously evaluate circumferential, longitudinal, and radial strain without being affected by through-plane motion. Moreover, the assessment of area change ratio may allow measuring regional myocardial deformation more accurately. We investigated the changes in each deformation parameter during acute coronary flow reduction, and evaluated whether the spatial extent of the abnormal values in each deformation parameter corresponded to that of the perfusion abnormality. Methods: In 10 dogs, myocardial strains of three directions and area change ratio were analyzed at baseline and during three different ischemic conditions. The peak systolic value and the post-systolic index (PSI) were measured in both the ischemic and normal segments. The function abnormality, derived from the deformation parameter, and the perfusion abnormality, derived from Evans blue staining, were evaluated in each segment during complete occlusion and the concordance rate between both abnormalities was calculated. Results: In all deformation parameters, the peak systolic value tended to gradually decrease and the PSI tended to gradually increase with the severity of flow reduction in the ischemic segment. Especially in area change ratio, significant changes were observed in both the peak systolic value and the PSI during occlusion compared to baseline. The concordance rate was the highest in the PSI assessed by area change ratio. Conclusions: Among 3D myocardial deformation parameters, area change ratio demonstrated better detectability of acute coronary flow reduction than conventional strain components. Area change ratio may be a useful parameter for detecting acute ischemia by 3D speckle tracking echocardiography.This is a post-peer-review, pre-copyedit version of an article published in Journal of Echocardiography. The final authenticated version is available online at: http://dx.doi.org/10.1007/s12574-019-00449-6.https://doi.org/10.1007/s12574-019-00449-

Myocardial layer-specific analysis of ischemic memory using speckle tracking echocardiography

The assessment of post-systolic shortening (PSS) by speckle tracking echocardiography allows myocardial ischemic memory imaging. Because the endocardial layer is more vulnerable to ischemia, the assessment of this layer might be useful for detecting ischemic memory. Serial echocardiographic data were acquired from nine dogs with 2 min of coronary occlusion followed by reperfusion. Regional deformation parameters were measured in the risk and normal areas. Using speckle tracking echocardiography, circumferential strain was analyzed in the endocardial, mid-wall, and epicardial layers; and radial strain was analyzed in the inner half, outer half and entire (transmural) layers. In the risk area, peak systolic and end-systolic strain in the circumferential and radial directions significantly decreased during occlusion, but recovered to the baseline levels immediately after reperfusion in all layers. However, circumferential post-systolic strain index (PSI), a parameter of PSS, significantly increased during occlusion, and the significant increases persisted until 20 min after reperfusion in the endocardial and mid-wall layers. Radial PSI tended to increase after reperfusion in the inner half and entire layers but these increases were not significant compared with baseline. In the normal area, systolic strains and PSI in the radial and circumferential directions hardly changed before and after occlusion/reperfusion in all layers. In layer-specific analysis with speckle tracking echocardiography, circumferential PSS in the endocardial and mid-wall layers may be useful for detecting ischemic memory. © 2014 Springer Science+Business Media.This is a post-peer-review, pre-copyedit version of an article published in International Journal of Cardiovascular Imaging. The final authenticated version is available online at: https://doi.org/10.1007/s10554-014-0388-x

Explicitly Multi-Modal Benchmarks for Multi-Objective Optimization

In multi-objective optimization, designing good benchmark problems is an important issue for improving solvers. Although many benchmark problems have been proposed and some of them became de facto standards, designing multimodal problems that have a controllable landscape is still an open problem especially for high-dimensional cases. We thus propose the Benchmark with Explicit Multimodality (BEM), which lets the benchmark designer specify the basins of attraction using a graph structure known as the reachability graph. In this article, we focus on the mathematical formulation of the BEM. We will see that the BEM has preferable characteristics such as (i) realizing user-specified local Pareto set, (ii) allowing high-dimensional design spaces and (iii) possessing nonseparability

Pre-steady-state kinetic studies of redox reactions catalysed by Bacillus subtilis ferredoxin-NADP+ oxidoreductase with NADP+/NADPH and ferredoxin

Ferredoxin-NADP+ oxidoreductase ([EC1.18.1.2], FNR) from Bacillus subtilis (BsFNR) is a homodimeric flavoprotein sharing structural homology with bacterial NADPH-thioredoxin reductase. Pre-steady-state kinetics of the reactions of BsFNR with NADP+, NADPH, NADPD (deuterated form) and B. subtilis ferredoxin (BsFd) using stopped-flow spectrophotometry were studied. Mixing BsFNR with NADP+ and NADPH yielded two types of charge-transfer (CT) complexes, oxidized FNR (FNRox)-NADPH and reduced FNR (FNRred)-NADP+, both having CT absorption bands centered at approximately 600 nm. After mixing BsFNRox with about a 10-fold molar excess of NADPH (forward reaction), BsFNR was almost completely reduced at equilibrium. When BsFNRred was mixed with NADP+, the amount of BsFNRox increased with increasing NADP+ concentration, but BsFNRred remained as the major species at equilibrium even with about 50-fold molar excess NADP+. In both directions, the hydride-transfer was the rate-determining step, where the forward direction rate constant (~ 500 s- 1) was much higher than the reverse one (< 10 s- 1). Mixing BsFdred with BsFNRox induced rapid formation of a neutral semiquinone form. This process was almost completed within 1 ms. Subsequently the neutral semiquinone form was reduced to the hydroquinone form with an apparent rate constant of 50 to 70 s- 1 at 10 °C, which increased as BsFdred increased from 40 to 120 μM. The reduction rate of BsFNRox by BsFdred was markedly decreased by premixing BsFNRox with BsFdox, indicating that the dissociation of BsFdox from BsFNRsq is rate-limiting in the reaction. The characteristics of the BsFNR reactions with NADP+/NADPH were compared with those of other types of FNRs. © 2016 Elsevier B.V. All rights reserved.Embargo Period 12 month

多変量データ解析のための特異ファイバー抽出と可視化

学位の種別: 課程博士審査委員会委員 : （主査）東京大学准教授 江尻 晶, 東京大学教授 杉山 将, 東京大学准教授 佐々木 岳彦, 九州大学教授 佐伯 修, 慶應義塾大学教授 藤代 一成, 会津大学教授 高橋 成雄University of Tokyo(東京大学