Translation plays an important role in plant adaptation to different abiotic and biotic stresses; however, the mechanisms involved in translational regulation during each specific response and their ...effect in translation are poorly understood in plants. In this work, we show that GCN2 promotes eIF2α phosphorylation upon contact with
spores, and that this phosphorylation is required for the proper establishment of plant defense against the fungus. In fact, independent
mutants display an enhanced susceptibility to
infection, which is highlighted by an increased cell death and reduced expression of ethylene- and jasmonic-related genes in the
mutants. eIF2α phosphorylation is not only triggered in the presence of the fungus, but interestingly, is also achieved in the sole presence of the microbe-associated molecular pattern (MAMP) chitin. Moreover, analysis of de novo protein synthesis by
Met-
Cys incorporation indicates that chitin treatment promotes a global inhibition of translation. Taken together, these results suggest that eIF2α phosphorylation by GCN2 is promoted in the presence of chitin and plays an important role in plant defense against
infection.
Protein-protein interactions discovered by yeast two-hybrid systems must be confirmed in vivo in a homologous system. In the case of plants, one of the easiest and fastest methods to validate protein ...interactions in vivo is the transient expression of the proteins in Nicotiana benthamiana leaves followed by coimmunoprecipitation. This method consists of the following steps: growth of the appropriate Agrobacterium tumefaciens cultures, preparation of the infiltration mixtures, infiltration into N. benthamiana leaves, protein extraction and immunoprecipitation. The utilization of epitope tags to immunoprecipitate and detect the proteins of interest is very useful in this procedure. In this chapter we describe a standard protocol to coimmunoprecipitate proteins expressed in N. benthamiana leaves.
Abstract
We present the first James Webb Space Telescope/NIRCam-led determination of 7 <
z
< 9 galaxy properties based on broadband imaging from 0.8 to 5
μ
m as part of the GLASS-JWST Early Release ...Science program. This is the deepest data set acquired at these wavelengths to date, with an angular resolution ≲0.″14. We robustly identify 13 galaxies with signal-to-noise ratio ≳ 8 in F444W from 8 arcmin
2
of data at
m
AB
≤ 28 from a combination of dropout and photometric redshift selection. From simulated data modeling, we estimate the dropout sample purity to be ≳90%. We find that the number density of these F444W-selected sources is broadly consistent with expectations from the UV luminosity function determined from Hubble Space Telescope data. We characterize galaxy physical properties using a Bayesian spectral energy distribution fitting method, finding a median stellar mass of 10
8.5
M
⊙
and age 140 Myr, indicating they started ionizing their surroundings at redshift
z
> 9.5. Their star formation main sequence is consistent with predictions from simulations. Lastly, we introduce an analytical framework to constrain main-sequence evolution at
z
> 7 based on galaxy ages and basic assumptions, through which we find results consistent with expectations from cosmological simulations. While this work only gives a glimpse of the properties of typical galaxies that are thought to drive the reionization of the universe, it clearly shows the potential of JWST to unveil unprecedented details of galaxy formation in the first billion years.
We present new ALMA observations of the O iii88 μm line and high angular resolution observations of the C ii158 μm line in a normal star forming galaxy at z = 7.1. Previous C ii observations of this ...galaxy had detected C ii emission consistent with the Lyα redshift but spatially slightly offset relative to the optical (UV-rest frame) emission. The new C ii observations reveal that the C ii emission is partly clumpy and partly diffuse on scales larger than about 1 kpc. O iii emission is also detected at high significance, offset relative to the optical counterpart in the same direction as the C ii clumps, but mostly not overlapping with the bulk of the C ii emission. The offset between different emission components (optical/UV and different far-IR tracers) is similar to that which is observed in much more powerful starbursts at high redshift. We show that the O iii emitting clump cannot be explained in terms of diffuse gas excited by the UV radiation emitted by the optical galaxy, but it requires excitation by in-situ (slightly dust obscured) star formation, at a rate of about 7 M⊙ yr-1. Within 20 kpc from the optical galaxy the ALMA data reveal two additional O iii emitting systems, which must be star forming companions. We discuss that the complex properties revealed by ALMA in the z ~ 7.1 galaxy are consistent with expectations by recent models and cosmological simulations, in which differential dust extinction, differential excitation and different metal enrichment levels, associated with different subsystems assembling a galaxy, are responsible for the various appearance of the system when observed with distinct tracers.
Abstract
We exploit James Webb Space Telescope (JWST) NIRCam observations from the GLASS-JWST-Early Release Science program to investigate galaxy stellar masses at
z
> 7. We first show that JWST ...observations reduce the uncertainties on the stellar mass by a factor of at least 5–10, when compared with the highest-quality data sets available to date. We then study the UV mass-to-light ratio, finding that galaxies exhibit a a two orders of magnitude range of
M
/
L
UV
values for a given luminosity, indicative of a broad variety of physical conditions and star formation histories. As a consequence, previous estimates of the cosmic stellar-mass density—based on an average correlation between UV luminosity and stellar mass—can be biased by as much as a factor of ∼6. Our first exploration demonstrates that JWST represents a new era in our understanding of stellar masses at
z
> 7 and, therefore, of the growth of galaxies prior to cosmic reionization.
We present new results from our search for z ~ 7 galaxies from deep spectroscopic observations of candidate z dropouts in the CANDELS fields. Despite the extremely low flux limits achieved by our ...sensitive observations, only two galaxies have robust redshift identifications, one from its Ly alpha emission line at z = 6.65, the other from its Lyman break, i.e., the continuum discontinuity at the Ly alpha wavelength consistent with a redshift of 6.42 but with no emission line. In addition, for 23 galaxies we present deep limits in the Ly alpha equivalent width derived from the nondetections in ultradeep observations. Using this new data as well as previous samples, we assemble a total of 68 candidate z ~ 7 galaxies with deep spectroscopic observations, of which 12 have a line detection. With this much enlarged sample we can place solid constraints on the declining fraction of Ly alpha emission in z ~ 7 Lyman-break galaxies compared to z ~ 6, both for bright and faint galaxies. Applying a simple analytical model, we show that the present data favor a patchy reionization process rather than a smooth one.
Summary
Root development and its response to environmental changes is crucial for whole plant adaptation. These responses include changes in transcript levels. Here, we show that the alternative ...polyadenylation (APA) of mRNA is important for root development and responses. Mutations in FIP1, a component of polyadenylation machinery, affects plant development, cell division and elongation, and response to different abiotic stresses. Salt treatment increases the amount of poly(A) site usage within the coding region and 5′ untranslated regions (5′‐UTRs), and the lack of FIP1 activity reduces the poly(A) site usage within these non‐canonical sites. Gene ontology analyses of transcripts displaying APA in response to salt show an enrichment in ABA signaling, and in the response to stresses such as salt or cadmium (Cd), among others. Root growth assays show that fip1‐2 is more tolerant to salt but is hypersensitive to ABA or Cd. Our data indicate that FIP1‐mediated alternative polyadenylation is important for plant development and stress responses.
Significance Statement
Genome information is transcribed into cells through mRNA transcription. This information can be amplified by post‐transcriptional mechanisms such as alternative splicing or polyadenylation. Genome‐wide analyses of poly(A) usage in response to salt revealed that FIP1‐mediated polyadenylation is needed for plant development and responses to stress.
Objectives
Patients with severe haemophilia A (HA) receive factor VIII (FVIII) replacement therapy as prophylaxis. myPKFiT®is an online medical application that allows authorized users to simulate ...dosing regimens with patient pharmacokinetic (PK) profiles based on only 2 blood samples. Our aim was to assess the impact of using this medical device in routine practice in terms of FVIII consumption and clinical outcomes.
Methods
Thirty‐six patients with severe HA on prophylaxis with Advate® were recruited in 3 centres in Spain. Annual bleeding rate (ABR), annual joint bleeding rate (AJBR) and annual FVIII consumption before and after adjustment were obtained using the patient’s clinical history (12 months before) and prospectively recorded data (12 months after), respectively. Adjustment was based on PK parameters provided by myPKFiT®, joint status and relative risk associated with physical activity and bleeding phenotype.
Results
ABR and AJBR were significantly reduced after adjustment in the overall sample (−2.2 ± 1.3, P = .018 and −1.9 ± 1.2, P = .012, respectively) and in patients aged >15 years (−2.6 ± 1.4, P = .011 and −2.0 ± 1.2, P = .005, respectively). Adjustment had an effect on the individual FVIII consumption of most patients: annual amount was reduced in 18 cases and increased in 14. There was no significant effect on the mean amount (198 784 ± 110 387) compared to that used the year prior to myPKFiT®‐adjusted prophylaxis (199 466 ± 103 670; P = .737).
Discussion
Our results suggest that PK‐guided prophylaxis using myPKFiT® improved clinical outcomes and optimized FVIII consumption in the study population. This personalized approach may reduce bleeding rates without significantly increasing the overall cost of FVIII therapy.
We present deep spectroscopic observations of a Lyman break galaxy (LBG) candidate (hereafter MACS1149-JD) at z ∼ 9.5 with the Hubble Space Telescope (HST) WFC3/IR grisms. The grism observations were ...taken at four distinct position angles, totaling 34 orbits with the G141 grism, although only 19 of the orbits are relatively uncontaminated along the trace of MACS1149-JD. We fit a three-parameter (z, F160W mag, and Ly equivalent width EW) LBG template to the three least contaminated grism position angles using a Markov chain Monte Carlo approach. The grism data alone are best fit with a redshift of (68% confidence), in good agreement with our photometric estimate of (68% confidence). Our analysis rules out Ly emission from MACS1149-JD above a 3 EW of 21 , consistent with a highly neutral IGM. We explore a scenario where the red Spitzer/IRAC 3.6-4.5 color of the galaxy previously pointed out in the literature is due to strong rest-frame optical emission lines from a very young stellar population rather than a 4000 break. We find that while this can provide an explanation for the observed IRAC color, it requires a lower redshift (z 9.1), which is less preferred by the HST imaging data. The grism data are consistent with both scenarios, indicating that the red IRAC color can still be explained by a 4000 break, characteristic of a relatively evolved stellar population. In this interpretation, the photometry indicates that a Myr stellar population is already present in this galaxy only ∼500 Myr after the big bang.
Abstract
Star-forming galaxies can exhibit strong morphological differences between the rest-frame far-UV and optical, reflecting inhomogeneities in star formation and dust attenuation. We exploit ...deep, high-resolution, NIRCAM seven-band observations to take a first look at the morphology of galaxies in the epoch of reionization (
z
> 7), and its variation in the rest-frame wavelength range between Ly
α
and 6000–4000 Å, at
z
= 7–12. We find no dramatic variations in morphology with wavelength—of the kind that would have overturned anything we have learned from the Hubble Space Telescope. No significant trends between morphology and wavelengths are detected using standard quantitative morphology statistics. We detect signatures of mergers/interactions in 4/19 galaxies. Our results are consistent with a scenario in which Lyman-break galaxies—observed when the universe is only 400–800 Myr old—are growing via a combination of rapid, galaxy-scale star formation supplemented by the accretion of star-forming clumps and interactions.
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