46 research outputs found
Central and Enteric Neuroprotective Effects by Eucommia ulmoides Extracts on Neurodegeneration in Rotenone-induced Parkinsonian Mouse
Parkinson’s disease (PD) is a progressive neurodegenerative disease of both the central and peripheral / enteric nervous systems. Oxidative stress and neuroinflammation are associated with the pathogenesis of PD, suggesting that anti-oxidative and anti-inflammatory compounds could be neuroprotective agents for PD. Eucommia ulmoides (EU) is a traditional herbal medicine which exerts neuroprotective effects by anti-inflammatory and anti-oxidative properties. Our previous study showed that treatment with chlorogenic acid, a component of EU, protected against neurodegeneration in the central and enteric nervous systems in a PD model. In this study, we examined the effects of EU extract (EUE) administration on dopaminergic neurodegeneration, glial response and α-synuclein expression in the substantia nigra pars compacta (SNpc), and intestinal enteric neurodegeneration in low-dose rotenone-induced PD model mice. Daily oral administration of EUE ameliorated dopaminergic neurodegeneration and α-synuclein accumulation in the SNpc. EUE treatment inhibited rotenone- induced decreases in the number of total astrocytes and in those expressing the antioxidant molecule metallothionein. EUE also prevented rotenone-induced microglial activation. Furthermore, EUE treatment exerted protective effects against intestinal neuronal loss in the PD model. These results suggest that EU exerts neuroprotective effects in the central and enteric nervous systems of rotenone-induced parkinsonism mice, in part by glial modification
Peptide barcoding for one-pot evaluation of sequence–function relationships of nanobodies
遊離型抗体の構造活性相関解析を迅速に評価可能とする新手法を開発. 京都大学プレスリリース. 2021-11-08.Optimisation of protein binders relies on laborious screening processes. Investigation of sequence–function relationships of protein binders is particularly slow, since mutants are purified and evaluated individually. Here we developed peptide barcoding, a high-throughput approach for accurate investigation of sequence–function relationships of hundreds of protein binders at once. Our approach is based on combining the generation of a mutagenised nanobody library fused with unique peptide barcodes, the formation of nanobody–antigen complexes at different ratios, their fine fractionation by size-exclusion chromatography and quantification of peptide barcodes by targeted proteomics. Applying peptide barcoding to an anti-GFP nanobody as a model, we successfully identified residues important for the binding affinity of anti-GFP nanobody at once. Peptide barcoding discriminated subtle changes in KD at the order of nM to sub-nM. Therefore, peptide barcoding is a powerful tool for engineering protein binders, enabling reliable one-pot evaluation of sequence–function relationships
Strange filamentary structures ("fireballs") around a merger galaxy in the Coma cluster of galaxies
We found an unusual complex of narrow blue filaments, bright blue knots, and
H-alpha emitting filaments and clouds, which morphologically resembled a
complex of ``fireballs,'' extending up to 80 kpc south from an E+A galaxy RB199
in the Coma cluster. The galaxy has a highly disturbed morphology indicative of
a galaxy--galaxy merger remnant. The narrow blue filaments extend in straight
shapes toward the south from the galaxy, and several bright blue knots are
located at the southern ends of the filaments. The Rc band absolute magnitudes,
half light radii and estimated masses of the bright knots are -12 - -13 mag,
200 - 300 pc and 10^6-7 Msolar, respectively. Long, narrow H-alpha emitting
filaments are connected at the south edge of the knots. The average color of
the fireballs is B - Rc = 0.5, which is bluer than RB199 (B - R = 0.99),
suggesting that most of the stars in the fireballs were formed within several
times 10^8 yr. The narrow blue filaments exhibit almost no H-alpha emission.
Strong H-alpha and UV emission appear in the bright knots. These
characteristics indicate that star formation recently ceased in the blue
filaments and now continues in the bright knots. The gas stripped by some
mechanism from the disk of RB199 may be traveling in the intergalactic space,
forming stars left along its trajectory. The most plausible fireball formation
mechanism is ram pressure stripping by high-speed collision between the galaxy
and the hot intra-cluster medium. The fireballs may be a snapshot of diffuse
intra-cluster population formation, or halo star population formation in a
cluster galaxy.Comment: 13 pages, 14 figures, submitted to Ap
A star-bursting proto-cluster in making associated to a radio galaxy at z=2.53 discovered by H_alpha imaging
We report a discovery of a proto-cluster in vigorous assembly and hosting
strong star forming activities, associated to a radio galaxy USS 1558-003 at
z=2.53, as traced by a wide-field narrow-band H_alpha imaging with MOIRCS on
Subaru Telescope. We find 68 H_alpha emitters with dust-uncorrected SFRs down
to 8.6 Msun/yr. Their spatial distribution indicates that there are three
prominent clumps of H_alpha emitters, one surrounding the radio galaxy and
another located at ~1.5 Mpc away to the south-west, and the other located in
between the two. These contiguous three systems are very likely to merge
together in the near future and may grow to a single more massive cluster at
later times. Whilst most H_alpha emitters reside in the "blue cloud" on the
color--magnitude diagram, some emitters have very red colors with
J-Ks>1.38(AB). Interestingly, such red H_alpha emitters are located towards the
faint end of the red sequence, and they tend to be located in the high density
clumps. We do not see any statistically significant difference in the
distributions of individual star formation rates or stellar masses of the
H_alpha emitters between the dense clumps and the other regions, suggesting
that this is one of the notable sites where the progenitors of massive galaxies
in the present-day clusters were in their vigorous formation phase. Finally, we
find that H_alpha emission of the radio galaxy is fairly extended spatially
over ~4.5 arcsec. However it is not as widespread as its Lya halo, meaning that
the Lya emission is indeed severely extended by resonant scattering.Comment: 14 pages, 11 figures, 3 tables, accepted for publication in Ap
High star formation activity in the central region of a distant cluster at z=1.46
We present an unbiased deep [OII] emission survey of a cluster XMMXCS
J2215.9-1738 at z=1.46, the most distant cluster to date with a detection of
extended X-ray emission. With wide-field optical and near-infrared cameras
(Suprime-Cam and MOIRCS, respectively) on Subaru telescope, we performed deep
imaging with a narrow-band filter NB912 (lambda_c=9139A, Delta_lambda=134A) as
well as broad-band filters (B, z', J and Ks). From the photometric catalogues,
we have identified 44 [OII] emitters in the cluster central region of 6'x6'
down to a dust-free star formation rate of 2.6 Msun/yr (3 sigma).
Interestingly, it is found that there are many [OII] emitters even in the
central high density region. In fact, the fraction of [OII] emitters to the
cluster members as well as their star formation rates and equivalent widths
stay almost constant with decreasing cluster-centric distance up to the cluster
core. Unlike clusters at lower redshifts (z<1) where star formation activity is
mostly quenched in their central regions, this higher redshift 2215 cluster
shows its high star formation activity even at its centre, suggesting that we
are beginning to enter the formation epoch of some galaxies in the cluster core
eventually. Moreover, we find a deficit of galaxies on the red sequence at
magnitudes fainter than ~M*+0.5 on the colour-magnitude diagram. This break
magnitude is brighter than that of lower redshift clusters, and it is likely
that we are seeing the formation phase of more massive red galaxies in the
cluster core at z~1. These results may indicate inside-out and down-sizing
propagation of star formation activity in the course of cluster evolution.Comment: 12 pages, 9 figures, 1 table, accepted for publication in MNRA
A large scale structure traced by [OII] emitters hosting a distant cluster at z=1.62
We present a panoramic narrow-band imaging survey of [OII] emitters in and
around the ClG J0218.3-0510 cluster at z=1.62 with Suprime-Cam on Subaru
telescope. 352 [OII] emitters were identified on the basis of narrow-band
excesses and photometric redshifts. We discovered a huge filamentary structure
with some clumps traced by [OII] emitters and found that the ClG J0218.3-0510
cluster is embedded in an even larger super-structure than the one reported
previously. 31 [OII] emitters were spectroscopically confirmed with the
detection of H-alpha and/or [OIII] emission lines by FMOS observations. In the
high density regions such as cluster core and clumps, star-forming [OII]
emitters show a high overdensity by a factor of more than 10 compared to the
field region. Although the star formation activity is very high even in the
cluster core, some massive quiescent galaxies also exits at the same time.
Furthermore, the properties of the individual [OII] emitters, such as star
formation rates, stellar masses and specific star formation rates, do not show
a significant dependence on the local density, either. Such lack of
environmental dependence is consistent with our earlier result by Hayashi et
al. (2011) on a z=1.5 cluster and its surrounding region. The fact that the
star-forming activity of galaxies in the cluster core is as high as that in the
field at z~1.6 may suggest that the star-forming galaxies are probably just in
a transition phase from a starburst mode to a quiescent mode, and are thus
showing comparable level of star formation rates to those in lower density
environments. We may be witnessing the start of the reversal of the local
SFR--density relation due to the "biased" galaxy formation and evolution in
high density regions at high this redshift, beyond which massive galaxies would
be forming vigorously in a more biased way in proto-cluster cores.Comment: 11 pages, 9 figures, 1 table, accepted for publication in MNRA
Properties of star-forming galaxies in a cluster and its surrounding structure at z=1.46
We conduct a narrow-band imaging survey of [OII] emitters over a 32'x23' area
in and around the XMMXCS J2215.9-1738 cluster at z=1.46 with
Subaru/Suprime-Cam, and select 380 [OII] emitting galaxies down to 1.4E-17
erg/s/cm2. Among them, 16 [OII] emitters in the cluster central region are
confirmed by NIR spectroscopy with Subaru/MOIRCS. We find that [OII] emitters
are distributed along filamentary large-scale structures around the cluster.
The z'-K vs K colour-magnitude diagram shows that a significantly higher
fraction of [OII] emitters is seen on the red sequence in the cluster core than
in other environments we define in this paper. It is likely that these red
galaxies are nearly passively evolving galaxies which host [OII] emitting AGNs,
rather than dust-reddened star-forming galaxies. We argue therefore that AGN
feedback may be one of the critical processes to quench star formation in
massive galaxies in high density regions. We also find that the cluster has
experienced high star formation activities at rates comparable to that in the
field at z=1.46. In addition, a mass-metallicity relation exists in the cluster
at z=1.46, which is similar to that of star-forming galaxies in the field at
z~2. These results all suggest that at z~1.5 star formation activity in the
cluster core becomes as high as those in low density environments and there is
apparently not yet a strong environmental dependence, except for the red
emitters.Comment: 19 pages, 17 figures, 4 tables, accepted for publication in MNRA
Mapping dusty star formation in and around a cluster at z=0.81 by wide-field imaging with AKARI
We present environmental dependence of dusty star forming activity in and
around the cluster RXJ1716.4+6708 at z=0.81 based on wide-field and
multi-wavelength observations with Suprime-Cam on the Subaru telescope and IRC
onboard the AKARI satellite. Our optical data shows that the optical colour
distribution of galaxies starts to dramatically change from blue to red at the
medium-density environment such as cluster outskirts, groups and filaments. By
combining with infrared data, we find that 15 micron galaxies tend to have
optical colours between the red sequence and the blue cloud with a tail into
the red sequence.
The spatial distribution of the 15 micron galaxies over ~200 arcmin^2 around
the cluster reveals that few 15 micron galaxies are detected in the cluster
central region. This is probably due to the low star forming activity in the
cluster core. However, interestingly, the fraction of 15 micron galaxies in the
medium-density environments is as high as in the low-density field, despite the
fact that the optical colours start to change in the medium-density
environments. Furthermore, we find that 15 micron galaxies which have optically
red colours (candidates for dusty red galaxies) and galaxies with high specific
star formation rates are also concentrated in the medium-density environment.
These results imply that the star forming activity in galaxies in groups and
filaments is enhanced due to some environmental effects specific to the
medium-density environment, and such a phenomenon is probably directly
connected to the truncation of star forming activity in galaxies seen as the
dramatic change in optical colours in such environments.Comment: 15 pages, 14 figures, accepted for publication in MNRA