35 research outputs found
An Intermediate-band imaging survey for high-redshift Lyman Alpha Emitters: The Mahoroba-11
We present results of our intermediate-band optical imaging survey for
high- Ly emitters (LAEs) using the prime focus camera, Suprime-Cam,
on the 8.2m Subaru Telescope. In our survey, we use eleven filters; four
broad-band filters (, , , and ) and seven
intermediate-band filters covering from 500 nm to 720 nm; we call this imaging
program as the Mahoroba-11. The seven intermediate-band filters are selected
from the IA filter series that is the Suprime-Cam intermediate-band filter
system whose spectral resolution is . Our survey has been made in a
sky area in the Subaru XMM Newton Deep Survey
field. We have found 409 IA-excess objects that provide us a large photometric
sample of strong emission-line objects. Applying the photometric redshift
method to this sample, we obtained a new sample of 198 LAE candidates at . We found that there is no evidence for evolution of the number density
and the star formation rate density for LAEs with between and 5.Comment: 46 pages, 15 figures, PASJ, Vol.57, No.6, in pres
Are Two z~6 Quasars Gravitationally Lensed ?
Several high-z (z > 5.7) quasars have been found in the course of Sloan
Digital Sky Survey. The presence of such very high-z quasars is expected to
give constraints on early structure formation. On one hand, it is suggested
that these most luminous objects at high redshift are biased toward the highly
magnified objects by gravitational lensing. To clarify the effect of
gravitational lensing on the high-z quasars, we began the imaging survey of
intervening lensing galaxies. Indeed our previous optical image showed that
SDSSp J104433.04+012502.2 at z=5.74 is gravitationally magnified by a factor 2.
In this paper, we report our new optical imaging of other two high-z quasars,
SDSSp J103027.10+052455.0 at z=6.28 and SDSSp J130608.26+035626.3 at z=5.99.
Since we find neither intervening galaxy nor counter image with i^{\prime} <
25.4-25.8 around each quasar, we conclude that they are not strongly magnified
regardless that a lens galaxy is dusty.Comment: 10 pages, 8 figures, Accepted for PAS
The Halpha Luminosity Function of the Galaxy Cluster Abell 521 at z = 0.25
We present an optical multicolor-imaging study of the galaxy cluster Abell
521 at , using Suprime-Cam on the Subaru Telescope, covering an area
of arcmin ( Mpc at ). Our imaging data taken with both a narrow-band filter,
(\AA and \AA), and broad-band filters,
, and allow us to find 165 H
emitters. We obtain the H luminosity function (LF) for the cluster
galaxies within 2 Mpc; the Schechter parameters are ,
Mpc, and erg s. Although the faint end slope, , is consistent with
that of the local cluster H LFs, the characteristic luminosity,
, is about 6 times (or mag) brighter. This strong
evolution implies that Abell 521 contains more active star-forming galaxies
than the local clusters, being consistent with the observed Butcher-Oemler
effect. However, the bright of Abell 521 may be, at least in part,
due to the dynamical condition of this cluster.Comment: 21 pages, 7 figures, ApJ, Part 1, in pres
A Subaru Search for Lyman-Alpha Emitters at z=5.8 with an Intermediate-Band Filter
We present the results of a survey for Ly-alpha emitters at z ~ 5.8 using a
new intermediate-band filter centered at lambda_c = 8275 AA with
Delta-lambda_FWHM = 340 AA (i.e., the spectroscopic resolution is R ~ 23) with
a combination with a traditional narrow-band centered at lambda_c = 8150 AA
with
Delta-lambda_FWHM = 120 AA (R ~ 68). Our observations were made with use of
the Subaru Prime Focus Camera, Suprime-Cam, on the 8.2 m Subaru telescope in a
sky area surrounding the high redshift quasar, SDSSp J104433.04-012522.2 at
z=5.74, covering an effective sky area with ~ 720 arcmin^2. In this survey, we
have found four Ly-alpha-emitter candidates from the intermediate-band image (z
\~ 5.8 with Delta z ~ 0.3). Combined with our previous results based on the
NB816 imaging, we discuss the star formation activity in galaxies between z ~
5.7 and z ~ 5.9.Comment: 8 pages, 8 figures. Accepted for publication in PAS
A Subaru Search for Lyman Emitters at Redshift 5.7
We present the results of a survey for Ly emitters at
based on optical narrow-band ( \AA ~ and \AA), and broad-band (, , , and )
observations of the field surrounding the high redshift quasar, SDSSp
J104433.04012522.2, on the 8.2 m Subaru Telescope with the Subaru Prime
Focus Camera, Suprime-Cam. This survey covers a sky area of
arcmin and a co-moving volume of
Mpc. We have found 20 candidates of Ly emitters at 5.7
with . Two of them have been confirmed star-forming
galaxies at and from our follow-up optical spectroscopy. We
discuss star-formation properties of the 20 objects from a statistical point of
view. Our survey leads to a new estimate of the star formation rate density at
, yr
Mpc.Comment: 18 pages, 19 figures, accepted for A
Extreme deformability of insect cell membranes is governed by phospholipid scrambling
昆虫の細胞は柔らかい! --細胞膜を柔らかくするタンパク質を発見--. 京都大学プレスリリース. 2021-06-09.Organization of dynamic cellular structure is crucial for a variety of cellular functions. In this study, we report that Drosophila and Aedes have highly elastic cell membranes with extremely low membrane tension and high resistance to mechanical stress. In contrast to other eukaryotic cells, phospholipids are symmetrically distributed between the bilayer leaflets of the insect plasma membrane, where phospholipid scramblase (XKR) that disrupts the lipid asymmetry is constitutively active. We also demonstrate that XKR-facilitated phospholipid scrambling promotes the deformability of cell membranes by regulating both actin cortex dynamics and mechanical properties of the phospholipid bilayer. Moreover, XKR-mediated construction of elastic cell membranes is essential for hemocyte circulation in the Drosophila cardiovascular system. Deformation of mammalian cells is also enhanced by the expression of Aedes XKR, and thus phospholipid scrambling may contribute to formation of highly deformable cell membranes in a variety of living eukaryotic cells
The whole blood transcriptional regulation landscape in 465 COVID-19 infected samples from Japan COVID-19 Task Force
「コロナ制圧タスクフォース」COVID-19患者由来の血液細胞における遺伝子発現の網羅的解析 --重症度に応じた遺伝子発現の変化には、ヒトゲノム配列の個人差が影響する--. 京都大学プレスリリース. 2022-08-23.Coronavirus disease 2019 (COVID-19) is a recently-emerged infectious disease that has caused millions of deaths, where comprehensive understanding of disease mechanisms is still unestablished. In particular, studies of gene expression dynamics and regulation landscape in COVID-19 infected individuals are limited. Here, we report on a thorough analysis of whole blood RNA-seq data from 465 genotyped samples from the Japan COVID-19 Task Force, including 359 severe and 106 non-severe COVID-19 cases. We discover 1169 putative causal expression quantitative trait loci (eQTLs) including 34 possible colocalizations with biobank fine-mapping results of hematopoietic traits in a Japanese population, 1549 putative causal splice QTLs (sQTLs; e.g. two independent sQTLs at TOR1AIP1), as well as biologically interpretable trans-eQTL examples (e.g., REST and STING1), all fine-mapped at single variant resolution. We perform differential gene expression analysis to elucidate 198 genes with increased expression in severe COVID-19 cases and enriched for innate immune-related functions. Finally, we evaluate the limited but non-zero effect of COVID-19 phenotype on eQTL discovery, and highlight the presence of COVID-19 severity-interaction eQTLs (ieQTLs; e.g., CLEC4C and MYBL2). Our study provides a comprehensive catalog of whole blood regulatory variants in Japanese, as well as a reference for transcriptional landscapes in response to COVID-19 infection
DOCK2 is involved in the host genetics and biology of severe COVID-19
「コロナ制圧タスクフォース」COVID-19疾患感受性遺伝子DOCK2の重症化機序を解明 --アジア最大のバイオレポジトリーでCOVID-19の治療標的を発見--. 京都大学プレスリリース. 2022-08-10.Identifying the host genetic factors underlying severe COVID-19 is an emerging challenge. Here we conducted a genome-wide association study (GWAS) involving 2, 393 cases of COVID-19 in a cohort of Japanese individuals collected during the initial waves of the pandemic, with 3, 289 unaffected controls. We identified a variant on chromosome 5 at 5q35 (rs60200309-A), close to the dedicator of cytokinesis 2 gene (DOCK2), which was associated with severe COVID-19 in patients less than 65 years of age. This risk allele was prevalent in East Asian individuals but rare in Europeans, highlighting the value of genome-wide association studies in non-European populations. RNA-sequencing analysis of 473 bulk peripheral blood samples identified decreased expression of DOCK2 associated with the risk allele in these younger patients. DOCK2 expression was suppressed in patients with severe cases of COVID-19. Single-cell RNA-sequencing analysis (n = 61 individuals) identified cell-type-specific downregulation of DOCK2 and a COVID-19-specific decreasing effect of the risk allele on DOCK2 expression in non-classical monocytes. Immunohistochemistry of lung specimens from patients with severe COVID-19 pneumonia showed suppressed DOCK2 expression. Moreover, inhibition of DOCK2 function with CPYPP increased the severity of pneumonia in a Syrian hamster model of SARS-CoV-2 infection, characterized by weight loss, lung oedema, enhanced viral loads, impaired macrophage recruitment and dysregulated type I interferon responses. We conclude that DOCK2 has an important role in the host immune response to SARS-CoV-2 infection and the development of severe COVID-19, and could be further explored as a potential biomarker and/or therapeutic target