オクタマ ニ オケル シンヨウジュジンコウリン ト コウヨウジュニジリンナイ デノ ノネズミルイコタイグンドウタイ

森林施業に関わる野ネズミ類の役割を明らかにする一環として,林相の異なる針葉樹人工林と広葉樹二次林を跨ぐ形で林内に生息する野ネズミ類を捕獲・放獣する方法により2006年から2009年まで個体群の変動を調査した。その結果,調査対象としたアカネズミ(Apodemus speciosus),ヒメネズミ(Apodemus argenteus)の捕獲個体数は2006年9月には延べワナ数675個で157個体,422回と最高の高密度状態を記録したが,11月から急激な減少が認められ,その後は1年以上ひと月の捕獲個体が数頭という低密度で推移したことから,野ネズミ類個体群にクラッシュが生じたものと判断した。アカネズミとヒメネズミの捕獲個体数の変動を比較すると,それぞれの生息特性を反映して急減の時期に3か月の時間的差異が見られた。しかし,全体的な変動の傾向は両種とも同様の推移を示した。針葉樹林と広葉樹林での生息状況を見ると,アカネズミでは広葉樹林の利用頻度が高く,秋季から冬季にかけて針葉樹林の依存度が増す傾向にあった。ヒメネズミでは針葉樹林のみの利用個体が多いものの,年によっては夏季に広葉樹林のみ利用する個体が増加した。また,いずれの種とも両方の林分を同時に利用している個体は少ないという傾向を得た。行動範囲に関しては,高密度下では大きく,ランダムに分布し,低密度下では小さく,限定的になる傾向が見られた。As a part of clarifying up the role of the forest field mouse, we investigated the fluctuation of the mouse population at an area between a coniferous plantation and a broad-leaved secondary forest in Okutama area, Tokyo. We attempted the capture-recapture method from 2006 to 2009. In September 2006, the captured number of the Apodemus speciosus and A. argenteus surveyed recorded the maximum (157 individuals, 422 caputures in 675 trap night ), but it started decreasing suddenly from November. We judged that a sudden drop occurred in the field mouse population because the captured number of these mice remained low over the next year. Start of the drop in A. argenteus was delayed three months compared to that of A. speciosus. However, both species had a similar population fluctuation tendency. A. speciosus generally used the broad-leaved forest frequently, and they showed increased dependence on the coniferous forest in fall. A. argenteus generally preferred the coniferous forest, but in summer some individuals of both species used only the broad-leaved forest. There were not many individuals whose home ranges extended across both kinds of forests. Home ranges of the field mice tended to be wide and random under a high density situation, but they became narrow and clustered under a low density situation

The Quiescent Intracluster Medium in the Core of the Perseus Cluster

Clusters of galaxies are the most massive gravitationally-bound objects in the Universe and are still forming. They are thus important probes of cosmological parameters and a host of astrophysical processes. Knowledge of the dynamics of the pervasive hot gas, which dominates in mass over stars in a cluster, is a crucial missing ingredient. It can enable new insights into mechanical energy injection by the central supermassive black hole and the use of hydrostatic equilibrium for the determination of cluster masses. X-rays from the core of the Perseus cluster are emitted by the 50 million K diffuse hot plasma filling its gravitational potential well. The Active Galactic Nucleus of the central galaxy NGC1275 is pumping jetted energy into the surrounding intracluster medium, creating buoyant bubbles filled with relativistic plasma. These likely induce motions in the intracluster medium and heat the inner gas preventing runaway radiative cooling; a process known as Active Galactic Nucleus Feedback. Here we report on Hitomi X-ray observations of the Perseus cluster core, which reveal a remarkably quiescent atmosphere where the gas has a line-of-sight velocity dispersion of 164+/-10 km/s in a region 30-60 kpc from the central nucleus. A gradient in the line-of-sight velocity of 150+/-70 km/s is found across the 60 kpc image of the cluster core. Turbulent pressure support in the gas is 4% or less of the thermodynamic pressure, with large scale shear at most doubling that estimate. We infer that total cluster masses determined from hydrostatic equilibrium in the central regions need little correction for turbulent pressure.Comment: 31 pages, 11 Figs, published in Nature July

Adult Neurogenesis Transiently Generates Oxidative Stress

An increasing body of evidence suggests that alterations in neurogenesis and oxidative stress are associated with a wide variety of CNS diseases, including Alzheimer’s disease, schizophrenia and Parkinson’s disease, as well as routine loss of function accompanying aging. Interestingly, the association between neurogenesis and the production of reactive oxidative species (ROS) remains largely unexamined. The adult CNS harbors two regions of persistent lifelong neurogenesis: the subventricular zone and the dentate gyrus (DG). These regions contain populations of quiescent neural stem cells (NSCs) that generate mature progeny via rapidly-dividing progenitor cells. We hypothesized that the energetic demands of highly proliferative progenitors generates localized oxidative stress that contributes to ROS-mediated damage within the neuropoietic microenvironment. In vivo examination of germinal niches in adult rodents revealed increases in oxidized DNA and lipid markers, particularly in the subgranular zone (SGZ) of the dentate gyrus. To further pinpoint the cell types responsible for oxidative stress, we employed an in vitro cell culture model allowing for the synchronous terminal differentiation of primary hippocampal NSCs. Inducing differentiation in primary NSCs resulted in an immediate increase in total mitochondria number and overall ROS production, suggesting oxidative stress is generated during a transient window of elevated neurogenesis accompanying normal neurogenesis. To confirm these findings in vivo, we identified a set of oxidation-responsive genes, which respond to antioxidant administration and are significantly elevated in genetic- and exercise-induced model of hyperactive hippocampal neurogenesis. While no direct evidence exists coupling neurogenesis-associated stress to CNS disease, our data suggest that oxidative stress is produced as a result of routine adult neurogenesis

Integrative Annotation of 21,037 Human Genes Validated by Full-Length cDNA Clones

The human genome sequence defines our inherent biological potential; the realization of the biology encoded therein requires knowledge of the function of each gene. Currently, our knowledge in this area is still limited. Several lines of investigation have been used to elucidate the structure and function of the genes in the human genome. Even so, gene prediction remains a difficult task, as the varieties of transcripts of a gene may vary to a great extent. We thus performed an exhaustive integrative characterization of 41,118 full-length cDNAs that capture the gene transcripts as complete functional cassettes, providing an unequivocal report of structural and functional diversity at the gene level. Our international collaboration has validated 21,037 human gene candidates by analysis of high-quality full-length cDNA clones through curation using unified criteria. This led to the identification of 5,155 new gene candidates. It also manifested the most reliable way to control the quality of the cDNA clones. We have developed a human gene database, called the H-Invitational Database (H-InvDB; http://www.h-invitational.jp/). It provides the following: integrative annotation of human genes, description of gene structures, details of novel alternative splicing isoforms, non-protein-coding RNAs, functional domains, subcellular localizations, metabolic pathways, predictions of protein three-dimensional structure, mapping of known single nucleotide polymorphisms (SNPs), identification of polymorphic microsatellite repeats within human genes, and comparative results with mouse full-length cDNAs. The H-InvDB analysis has shown that up to 4% of the human genome sequence (National Center for Biotechnology Information build 34 assembly) may contain misassembled or missing regions. We found that 6.5% of the human gene candidates (1,377 loci) did not have a good protein-coding open reading frame, of which 296 loci are strong candidates for non-protein-coding RNA genes. In addition, among 72,027 uniquely mapped SNPs and insertions/deletions localized within human genes, 13,215 nonsynonymous SNPs, 315 nonsense SNPs, and 452 indels occurred in coding regions. Together with 25 polymorphic microsatellite repeats present in coding regions, they may alter protein structure, causing phenotypic effects or resulting in disease. The H-InvDB platform represents a substantial contribution to resources needed for the exploration of human biology and pathology

Hitomi (ASTRO-H) X-ray Astronomy Satellite

The Hitomi (ASTRO-H) mission is the sixth Japanese x-ray astronomy satellite developed by a large international collaboration, including Japan, USA, Canada, and Europe. The mission aimed to provide the highest energy resolution ever achieved at E  >  2  keV, using a microcalorimeter instrument, and to cover a wide energy range spanning four decades in energy from soft x-rays to gamma rays. After a successful launch on February 17, 2016, the spacecraft lost its function on March 26, 2016, but the commissioning phase for about a month provided valuable information on the onboard instruments and the spacecraft system, including astrophysical results obtained from first light observations. The paper describes the Hitomi (ASTRO-H) mission, its capabilities, the initial operation, and the instruments/spacecraft performances confirmed during the commissioning operations for about a month