3,838 research outputs found
Identification of WRKY transcription factors associated with leaf and corolla senescence in Petunia hybrida
Several families of transcription factors (TFs) control the progression of senescence. Many key TFs belonging to the WRKY family have been described to play crucial roles in the regulation of leaf senescence, mainly in Arabidopsis. However, little is known about senescence-associated WRKY members in floricultural species. Delay of senescence in leaves and petals of Petunia hybrida, a worldwide ornamental crop are highly appreciated traits. In this work, starting from 28 differentially expressed WRKY genes of Arabidopsis during the progression of leaf senescence, we identified the orthologous in P. hybrida and explored the expression profiles of 20 PhWRKY genes during the progression of natural (age-related) leaf and corolla senescence as well as in the corollas of flowers undergoing pollination-induced senescence. Simultaneous visualization showed consistent and similar expression profiles of PhWRKYs during natural leaf and corolla senescence, although weak expression changes were observed during pollination-induced senescence. Comparable expression trends between PhWRKYs and the corresponding genes of Arabidopsis were observed during leaf senescence, although more divergences were found in petals of pollinated petunia flowers. Integration of expression data with phylogenetics, conserved motif and cis-regulatory element analyses were used to establish a list of solid candidates that could regulate more than one senescence process. Our results suggest that several members of the WRKY family of TFs are tightly linked to the regulation of senescence in P. hybrida.Fil: Astigueta, Francisco Horacio. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Agrobiotecnología y Biología Molecular. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Agrobiotecnología y Biología Molecular; ArgentinaFil: Baigorria, Amilcar H.. Universidad Nacional de San Martín; ArgentinaFil: Garcia, Martín Nahuel. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación En Ciencias Veterinarias y Agronómicas. Instituto de Agrobiotecnología y Biología Molecular. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Agrobiotecnología y Biología Molecular; ArgentinaFil: Delfosse, Verónica Cecilia. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación En Ciencias Veterinarias y Agronómicas. Instituto de Agrobiotecnología y Biología Molecular. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Agrobiotecnología y Biología Molecular; ArgentinaFil: González, Sergio Alejandro. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación En Ciencias Veterinarias y Agronómicas. Instituto de Agrobiotecnología y Biología Molecular. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Agrobiotecnología y Biología Molecular; ArgentinaFil: Perez de la Torre, Mariana Cecilia. Instituto Nacional de Tecnología Agropecuaria; ArgentinaFil: Moschen, Sebastián Nicolás. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación En Ciencias Veterinarias y Agronómicas. Instituto de Agrobiotecnología y Biología Molecular. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Agrobiotecnología y Biología Molecular; ArgentinaFil: Lia, Verónica Viviana. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación En Ciencias Veterinarias y Agronómicas. Instituto de Agrobiotecnología y Biología Molecular. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Agrobiotecnología y Biología Molecular; ArgentinaFil: Heinz, Ruth Amelia. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación En Ciencias Veterinarias y Agronómicas. Instituto de Agrobiotecnología y Biología Molecular. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Agrobiotecnología y Biología Molecular; ArgentinaFil: Fernandez, Paula del Carmen. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación En Ciencias Veterinarias y Agronómicas. Instituto de Agrobiotecnología y Biología Molecular. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Agrobiotecnología y Biología Molecular; ArgentinaFil: Trupkin, Santiago Ariel. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación En Ciencias Veterinarias y Agronómicas. Instituto de Agrobiotecnología y Biología Molecular. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Agrobiotecnología y Biología Molecular; Argentin
zCOSMOS 20k: Satellite galaxies are the main drivers of environmental effects in the galaxy population at least to z~0.7
We explore the role of environment in the evolution of galaxies over
0.1<z<0.7 using the final zCOSMOS-bright data set. Using the red fraction of
galaxies as a proxy for the quenched population, we find that the fraction of
red galaxies increases with the environmental overdensity and with the stellar
mass, consistent with previous works. As at lower redshift, the red fraction
appears to be separable in mass and environment, suggesting the action of two
processes: mass and environmental quenching. The parameters describing these
appear to be essentially the same at z~0.7 as locally. We explore the relation
between red fraction, mass and environment also for the central and satellite
galaxies separately, paying close attention to the effects of impurities in the
central-satellite classification and using carefully constructed samples
matched in stellar mass. There is little evidence for a dependence of the red
fraction of centrals on overdensity. Satellites are consistently redder at all
overdensities, and the satellite quenching efficiency increases with
overdensity at 0.1<z<0.4. This is less marked at higher redshift, but both are
nevertheless consistent with the equivalent local measurements. At a given
stellar mass, the fraction of galaxies that are satellites also increases with
the overdensity. At a given overdensity and mass, the obtained relation between
the environmental quenching and the satellite fraction agrees well with the
satellite quenching efficiency, demonstrating that the environmental quenching
in the overall population is consistent with being entirely produced through
the satellite quenching process at least up to z=0.7. However, despite the
unprecedented size of our high redshift samples, the associated statistical
uncertainties are still significant and our statements should be understood as
approximations to physical reality, rather than physically exact formulae.Comment: 22 pages, 19 figures, submitted to MNRA
Smelling the dark proteome: Functional characterization of PITH domain-containing protein 1 (C1orf128) in olfactory metabolism
The Human Proteome Project (HPP) consortium aims to functionally characterize the dark proteome. On the basis of the relevance of olfaction in early neurodegeneration, we have analyzed the dark proteome using data mining in public resources and omics data sets derived from the human olfactory system. Multiple dark proteins localize at synaptic terminals and may be involved in amyloidopathies such as Alzheimer’s disease (AD). We have characterized the dark PITH domain-containing protein 1 (PITHD1) in olfactory metabolism using bioinformatics, proteomics, in vitro and in vivo studies, and neuropathology. PITHD1–/– mice exhibit olfactory bulb (OB) proteome changes related to synaptic transmission, cognition, and memory. OB PITHD1 expression increases with age in wild-type (WT) mice and decreases in Tg2576 AD mice at late stages. The analysis across 6 neurological disorders reveals that olfactory tract (OT) PITHD1 is specifically upregulated in human AD. Stimulation of olfactory neuroepithelial (ON) cells with PITHD1 alters the ON phosphoproteome, modifies the proliferation rate, and induces a pro-inflammatory phenotype. This workflow applied by the Spanish C-HPP and Human Brain Proteome Project (HBPP) teams across the ON-OB-OT axis can be adapted as a guidance to decipher functional features of dark proteins. Data are available via ProteomeXchange with identifiers PXD018784 and PXD021634
The VIMOS VLT Deep Survey :Evolution of the major merger rate since z~1 from spectroscopicaly confirmed galaxy pairs
From the VIMOS VLT Deep Survey we use a sample of 6447 galaxies with I_{AB} <
24 to identify 251 pairs of galaxies, each member with a secure spectroscopic
redshift, which are close in both projected separation and in velocity. We find
that at z ~ 0.9, 10.9 +/- 3.2 % of galaxies with M_B(z) < -18-Qz are in pairs
with separations dr < 20 kpc/h, dv < 500 km/s, and with dM_B < 1.5,
significantly larger than 3.76 +/- 1.71 % at z ~ 0.5; we find that the pair
fraction evolves as (1+z)^m with m = 2.49 +/- 0.56. For brighter galaxies with
M_B(z=0) < -18.77, the pair fraction is higher and its evolution with redshift
is somewhat flatter with m=1.88 \pm 0.40, a property also observed for galaxies
with increasing stellar masses. Early type, dry mergers, pairs increase their
relative fraction from 3 % at z ~ 0.9 to 12 % at z ~ 0.5. We find that the
merger rate evolves as N_{mg}=(9.05 +/- 3.76) * 10^{-4}) * (1+z)^{2.43 +/-
0.76}. We find that the merger rate of galaxies with M_B(z) < -18-Qz has
significantly evolved since z ~ 1. The merger rate is increasing more rapidly
with redshift for galaxies with decreasing luminosities, indicating that the
flat evolution found for bright samples is not universal. The merger rate is
also strongly dependent on the spectral type of galaxies involved, late type
mergers being more frequent in the past, while early type mergers are more
frequent today, contributing to the rise in the local density of early type
galaxies. About 20 % of the stellar mass in present day galaxies with
log(M/M_{sun}) > 9.5 has been accreted through major merging events since z ~
1, indicating that major mergers have contributed significantly to the growth
in stellar mass density of bright galaxies over the last half of the life of
the Universe.Comment: 22 pages, 19 figures, accepted in A&
Recommended from our members
Erratum to: 36th International Symposium on Intensive Care and Emergency Medicine: Brussels, Belgium. 15-18 March 2016.
[This corrects the article DOI: 10.1186/s13054-016-1208-6.]
Obscured AGN at z~1 from the zCOSMOS-Bright Survey I. Selection and Optical Properties of a [Ne v]-selected sample
A sample of 94 narrow line AGN with 0.65<z<1.20 has been selected from the
20k-Bright zCOSMOS galaxy sample by detection of the high-ionization [NeV]3426
line. Taking advantage of the large amount of data available in the COSMOS
field, the properties of the [NeV]-selected Type-2 AGN have been investigated,
focusing on their host galaxies, X-ray emission, and optical line flux ratios.
Finally, the diagnostic developed by Gilli et al. (2010), based on the X-ray to
[NeV] luminosity ratio, has been exploited to search for the more heavily
obscured AGN. We found that [Ne v]-selected narrow line AGN have Seyfert 2-like
optical spectra, although with emission line ratios diluted by a star-forming
component. The ACS morphologies and stellar component in the optical spectra
indicate a preference for our Type-2 AGN to be hosted in early-spirals with
stellar masses greater than 10^(9.5-10)Msun, on average higher than those of
the galaxy parent sample. The fraction of galaxies hosting [NeV]-selected
obscured AGN increases with the stellar mass, reaching a maximum of about 3% at
2x10^11 Msun. A comparison with other selection techniques at z~1 shows that
the detection of the [Ne v] line is an effective method to select AGN in the
optical band, in particular the most heavily obscured ones, but can not provide
by itself a complete census of AGN2. Finally, the high fraction of
[NeV]-selected Type-2 AGN not detected in medium-deep Chandra observations
(67%) is suggestive of the inclusion of Compton-thick sources in our sample.
The presence of a population of heavily obscured AGN is corroborated by the
X-ray to [NeV] ratio; we estimated, by mean of X-ray stacking technique and
simulations, that the Compton-thick fraction in our sample of Type-2 AGN is
43+-4%, in good agreement with standard assumptions by the XRB synthesis
models.Comment: 14 pages, 12 figures, accepted for publication in A&
A group-galaxy cross-correlation function analysis in zCOSMOS
We present a group-galaxy cross-correlation analysis using a group catalog
produced from the 16,500 spectra from the optical zCOSMOS galaxy survey. Our
aim is to perform a consistency test in the redshift range 0.2 < z < 0.8
between the clustering strength of the groups and mass estimates that are based
on the richness of the groups. We measure the linear bias of the groups by
means of a group-galaxy cross-correlation analysis and convert it into mass
using the bias-mass relation for a given cosmology, checking the systematic
errors using realistic group and galaxy mock catalogs. The measured bias for
the zCOSMOS groups increases with group richness as expected by the theory of
cosmic structure formation and yields masses that are reasonably consistent
with the masses estimated from the richness directly, considering the scatter
that is obtained from the 24 mock catalogs. An exception are the richest groups
at high redshift (estimated to be more massive than 10^13.5 M_sun), for which
the measured bias is significantly larger than for any of the 24 mock catalogs
(corresponding to a 3-sigma effect), which is attributed to the extremely large
structure that is present in the COSMOS field at z ~ 0.7. Our results are in
general agreement with previous studies that reported unusually strong
clustering in the COSMOS field.Comment: 13 pages, 9 figures, published in Ap
The zCOSMOS 20k Group Catalog
We present an optical group catalog between 0.1 < z < 1 based on 16,500
high-quality spectroscopic redshifts in the completed zCOSMOS-bright survey.
The catalog published herein contains 1498 groups in total and 192 groups with
more than five observed members. The catalog includes both group properties and
the identification of the member galaxies. Based on mock catalogs, the
completeness and purity of groups with three and more members should be both
about 83% with respect to all groups that should have been detectable within
the survey, and more than 75% of the groups should exhibit a one-to-one
correspondence to the "real" groups. Particularly at high redshift, there are
apparently more galaxies in groups in the COSMOS field than expected from mock
catalogs. We detect clear evidence for the growth of cosmic structure over the
last seven billion years in the sense that the fraction of galaxies that are
found in groups (in volume-limited samples) increases significantly with cosmic
time. In the second part of the paper, we develop a method for associating
galaxies that only have photo-z to our spectroscopically identified groups. We
show that this leads to improved definition of group centers, improved
identification of the most massive galaxies in the groups, and improved
identification of central and satellite galaxies, where we define the former to
be galaxies at the minimum of the gravitational potential wells. Subsamples of
centrals and satellites in the groups can be defined with purities up to 80%,
while a straight binary classification of all group and non-group galaxies into
centrals and satellites achieves purities of 85% and 75%, respectively, for the
spectroscopic sample.Comment: 26 pages, 21 figures, published in ApJ (along with machine-readable
tables
The XMM-Newton Wide-Field Survey in the COSMOS field (XMM-COSMOS): demography and multiwavelength properties of obscured and unobscured luminous AGN
We report the final optical identifications of the medium-depth (~60 ksec),
contiguous (2 deg^2) XMM-Newton survey of the COSMOS field. XMM-Newton has
detected ~800 X-ray sources down to limiting fluxes of ~5x10^{-16},
~3x10^{-15}, and ~7x10^{-15} erg/cm2/s in the 0.5-2 keV, 2-10 keV and 5-10 keV
bands, respectively. The work is complemented by an extensive collection of
multi-wavelength data from 24 micron to UV, available from the COSMOS survey,
for each of the X-ray sources, including spectroscopic redshifts for ~50% of
the sample, and high-quality photometric redshifts for the rest. The XMM and
multiwavelength flux limits are well matched: 1760 (98%) of the X-ray sources
have optical counterparts, 1711 (~95%) have IRAC counterparts, and 1394 (~78%)
have MIPS 24micron detections. Thanks to the redshift completeness (almost
100%) we were able to constrain the high-luminosity tail of the X-ray
luminosity function confirming that the peak of the number density of
logL_X>44.5 AGN is at z~2. Spectroscopically-identified obscured and unobscured
AGN, as well as normal and starforming galaxies, present well-defined optical
and infrared properties. We devised a robust method to identify a sample of
~150 high redshift (z>1), obscured AGN candidates for which optical
spectroscopy is not available. We were able to determine that the fraction of
the obscured AGN population at the highest (L_X>10^{44} erg s^{-1}) X-ray
luminosity is ~15-30% when selection effects are taken into account, providing
an important observational constraint for X-ray background synthesis. We
studied in detail the optical spectrum and the overall spectral energy
distribution of a prototypical Type 2 QSO, caught in a stage transitioning from
being starburst dominated to AGN dominated, which was possible to isolate only
thanks to the combination of X-ray and infrared observations.Comment: ApJ, in press. 59 pages, 14 figures, 2 Tables. A few typos corrected
and a reference added. Table 2 is also available at
http://www.mpe.mpg.de/XMMCosmos/xmm53_release ; a version of the paper in ApJ
format (27 pages) is available at
http://www.mpe.mpg.de/XMMCosmos/xmm53_release/brusa_xmmcosmos_optid.pd
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