1,756 research outputs found
Identification of Novel miRNAs and miRNA Dependent Developmental Shifts of Gene Expression in Arabidopsis thaliana
microRNAs (miRNAs) are small, endogenous RNAs of 20∼25 nucleotides, processed from stem-loop regions of longer RNA precursors. Plant miRNAs act as negative regulators of target mRNAs predominately by slicing target transcripts, and a number of miRNAs play important roles in development. We analyzed a number of published datasets from Arabidopsis thaliana to characterize novel miRNAs, novel miRNA targets, and miRNA-regulated developmental changes in gene expression. These data include microarray profiling data and small RNA (sRNA) deep sequencing data derived from miRNA biogenesis/transport mutants, microarray profiling data of mRNAs in a developmental series, and computational predictions of conserved genomic stem-loop structures. Our conservative analyses identified five novel mature miRNAs and seven miRNA targets, including one novel target gene. Two complementary miRNAs that target distinct mRNAs were encoded by one gene. We found that genes targeted by known miRNAs, and genes up-regulated or down-regulated in miRNA mutant inflorescences, are highly expressed in the wild type inflorescence. In addition, transcripts upregulated within the mutant inflorescences were abundant in wild type leaves and shoot meristems and low in pollen and seed. Downregulated transcripts were abundant in wild type pollen and seed and low in shoot meristems, roots and leaves. Thus, disrupting miRNA function causes the inflorescence transcriptome to resemble the leaf and meristem and to differ from pollen and seed. Applications of our computational approach to other species and the use of more liberal criteria than reported here will further expand the number of identified miRNAs and miRNA targets. Our findings suggest that miRNAs have a global role in promoting vegetative to reproductive transitions in A. thaliana
The Lantern Vol. 20, No. 2, Spring 1952
• Linda Rellah, A Modern Fairy Tale With A Moral • Phantasy • Maiden Flight • Death of the Tired Ford • The Wall • Trolley Travellers • Aubade • To a Classmate • Substitute • Recital • Airborne • New England Summer • Mississippi Summer • Western Wind, When Wilt Thou • When? • College, I Love It! • Today! • Daily Things • The Wily Old Philosopher • Modern Verse • Faded • Have You Everhttps://digitalcommons.ursinus.edu/lantern/1056/thumbnail.jp
The Lantern Vol. 21, No. 1, Fall 1952
• Dolly and Manny • The Man on the Stoop • Just a Plain, Simple Girl • If Damon Runyon Had Reviewed George Meredith\u27s Novel, The Ordeal of Richard Feverel • Two Before Dinner • A Treatise on the Noble Art of Warfare • My Neighbor, Zakeya • Elegy • What\u27s This Card For, Offisser? • Winter\u27s Loneliness • Birth • Of Thee I Sting • For Your Knowing • Beauty Defined • Daybreak at Home • Mood • Leaves • Love Recaptured • Awake Again • Silence • Sea-Song • The City • The Voice of Autumn Earthhttps://digitalcommons.ursinus.edu/lantern/1058/thumbnail.jp
RNA Interference Can Rebalance the Nitrogen Sink of Maize Seeds without Losing Hard Endosperm
Background: One of the goals of plant breeding is to create crops to provide better nutrition for humans and livestock. Insufficient intake of protein is one of the most severe factors affecting the growth and development of children in developing countries. More than a century ago, in 1896, Hopkins initiated the well-known Illinois long-term selection for maize seed protein concentration, yielding four protein strains. By continuously accumulating QTLs, Illinois High Protein (IHP) reached a protein level 2.5-fold higher than normal maize, with the most increased fraction being the zein protein, which was shown to contain no lysine soon after the long-term selection program initiated. Therefore, IHP is of little value for feeding humans and monogastric animals. Although high-lysine lines of non-vitreous mutants were based on reduced zeins, the kernel soft texture precluded their practical use. Kernel hardness in opaque 2 (o2) could be restored in quality protein maize (QPM) with quantitative trait loci called o2 modifiers (Mo2s), but those did not increase total protein levels. Methods: The most predominant zeins are the 22- and 19-kDa a-zeins. To achieve a combination of desired traits, we used RNA interference (RNAi) against both a-zeins in IHP and evaluated the silencing effect by SDS-PAGE. Total protein, amino acid composition and kernel texture were analyzed. Conclusions: The a-zeins were dramatically reduced, but the high total seed protein level remained unchanged by complementary increase of non-zein proteins. Moreover, the residual zein levels still allowed for a vitreous hard seed. Suc
Performance of a Kinetic Inductance Phonon-Mediated Detector at the NEXUS Cryogenic Facility
Microcalorimeters that leverage microwave kinetic inductance detectors to
read out phonon signals in the particle-absorbing target, referred to as
kinetic inductance phonon-mediated (KIPM) detectors, offer an attractive
detector architecture to probe dark matter (DM) down to the fermionic thermal
relic mass limit. A prototype KIPM detector featuring a single aluminum
resonator patterned onto a 1-gram silicon substrate was operated in the NEXUS
low-background facility at Fermilab for characterization and evaluation of this
detector architecture's efficacy for a dark matter search. An energy
calibration was performed by exposing the bare substrate to a pulsed source of
470 nm photons, resulting in a baseline resolution on the energy absorbed by
the phonon sensor of eV, a factor of two better than the current
state-of-the-art, enabled by millisecond-scale quasiparticle lifetimes.
However, due to the sub-percent phonon collection efficiency, the resolution on
energy deposited in the substrate is limited to eV. We
further model the signal pulse shape as a function of device temperature to
extract quasiparticle lifetimes, as well as the observed noise spectra, both of
which impact the baseline resolution of the sensor
Activated monocytes in peritumoral stroma of hepatocellular carcinoma foster immune privilege and disease progression through PD-L1
Macrophages (Mφ) are prominent components of solid tumors and exhibit distinct phenotypes in different microenvironments. We have recently found that tumors can alter the normal developmental process of Mφ to trigger transient activation of monocytes in peritumoral stroma. We showed that a fraction of monocytes/Mφ in peritumoral stroma, but not in cancer nests, expresses surface PD-L1 (also termed B7-H1) molecules in tumors from patients with hepatocellular carcinoma (HCC). Monocytes activated by tumors strongly express PD-L1 proteins with kinetics similar to their activation status, and significant correlations were found between the levels of PD-L1+ and HLA-DRhigh on tumor-infiltrating monocytes. Autocrine tumor necrosis factor α and interleukin 10 released from activated monocytes stimulated monocyte expression of PD-L1. The PD-L1+ monocytes effectively suppressed tumor-specific T cell immunity and contributed to the growth of human tumors in vivo; the effect could be reversed by blocking PD-L1 on those monocytes. Moreover, we found that PD-L1 expression on tumor-infiltrating monocytes increased with disease progression, and the intensity of the protein was associated with high mortality and reduced survival in the HCC patients. Thus, expression of PD-L1 on activated monocytes/Mφ may represent a novel mechanism that links the proinflammatory response to immune tolerance in the tumor milieu
Search for a Technicolor omega_T Particle in Events with a Photon and a b-quark Jet at CDF
If the Technicolor omega_T particle exists, a likely decay mode is omega_T ->
gamma pi_T, followed by pi_T -> bb-bar, yielding the signature gamma bb-bar. We
have searched 85 pb^-1 of data collected by the CDF experiment at the Fermilab
Tevatron for events with a photon and two jets, where one of the jets must
contain a secondary vertex implying the presence of a b quark. We find no
excess of events above standard model expectations. We express the result of an
exclusion region in the M_omega_T - M_pi_T mass plane.Comment: 14 pages, 2 figures. Available from the CDF server (PS with figs):
http://www-cdf.fnal.gov/physics/pub98/cdf4674_omega_t_prl_4.ps
FERMILAB-PUB-98/321-
Observation of Hadronic W Decays in t-tbar Events with the Collider Detector at Fermilab
We observe hadronic W decays in t-tbar -> W (-> l nu) + >= 4 jet events using
a 109 pb-1 data sample of p-pbar collisions at sqrt{s} = 1.8 TeV collected with
the Collider Detector at Fermilab (CDF). A peak in the dijet invariant mass
distribution is obtained that is consistent with W decay and inconsistent with
the background prediction by 3.3 standard deviations. From this peak we measure
the W mass to be 77.2 +- 4.6 (stat+syst) GeV/c^2. This result demonstrates the
presence of two W bosons in t-tbar candidates in the W (-> l nu) + >= 4 jet
channel.Comment: 20 pages, 4 figures, submitted to PR
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