We report the detection of three RR Lyrae (RRL) stars (two RRc and one RRab) in the ultra-faint dwarf (UFD) galaxy Centaurus I (Cen I) and two Milky Way (MW) delta Scuti/SX Phoenicis stars based on multi-epoch giz DECam observations. The two RRc stars are located within two times the half-light radius (r ( h )) of Cen I, while the RRab star (CenI-V3) is at similar to 6 r ( h ). The presence of three distant RRL stars clustered this tightly in space represents a 4.7 sigma excess relative to the smooth distribution of RRL in the Galactic halo. Using the newly detected RRL stars, we obtain a distance modulus to Cen I of mu (0) = 20.354 +/- 0.002 mag (sigma = 0.03 mag), a heliocentric distance of D (circle dot) = 117.7 +/- 0.1 kpc (sigma = 1.6 kpc), with systematic errors of 0.07 mag and 4 kpc. The location of the Cen I RRL stars in the Bailey diagram is in agreement with other UFD galaxies (mainly Oosterhoff II). Finally, we study the relative rate of RRc+RRd (RRcd) stars (f (cd)) in UFD and classical dwarf galaxies. The full sample of MW dwarf galaxies gives a mean of f (cd) = 0.28. While several UFD galaxies, such as Cen I, present higher RRcd ratios, if we combine the RRL populations of all UFD galaxies, the RRcd ratio is similar to the one obtained for the classical dwarfs (f (cd) similar to 0.3). Therefore, there is no evidence for a different fraction of RRcd stars in UFD and classical dwarf galaxies.

We present the discovery of a candidate ultra-faint Milky-Way satellite, Eridanus IV (DELVE J0505-0931), detected in photometric data from the DECam Local Volume Exploration survey (DELVE). Eridanus IV is a faint (M-V = - 4.7 +/- 0.2), extended (r(1/2)=75(-13)(+16) pc ), and elliptical (epsilon = 0.54 +/- 0.1) system at a heliocentric distance of 76.7(-6.1)(+4.0)kpc, with a stellar population that is well described by an old, metal-poor isochrone (age of tau similar to 13.0 Gyr and metallicity of [Fe/H] less than or similar to - 2.1 dex). These properties are consistent with the known population of ultra-faint Milky-Way satellite galaxies. Eridanus IV is also prominently detected using proper-motion measurements from Gaia Early Data Release 3, with a systemic proper motion of (mu(alpha) cos delta,mu(delta))=(+0.25 +/- 0.06,-0.10 +/- 0.05) mas yr(-1) measured from its horizontal branch and red-giant-branch member stars. We find that the spatial distribution of likely member stars hints at the possibility that the system is undergoing tidal disruption.

A fully sampled and hitherto highest resolution and sensitivity observation of neutral hydrogen (H I) in the Leo Triplet (NGC 3628, M 65/NGC 3623, and M 66/NGC 3627) reveals six H I structures beyond the three galaxies. We present detailed results of the morphologies and kinematics of these structures, which can be used for future simulations. In particular, we detect a two-arm structure in the plume of NGC 3628 for the first time, which can be explained by a tidal interaction model. The optical counterpart of the plume is mainly associated with the southern arm. The connecting part (base) of the plume (directed eastward) with NGC 3628 is located at the blueshifted (western) side of NGC 3628. Two bases appear to be associated with the two arms of the plume. A clump with a reversed velocity gradient (relative to the velocity gradient of M 66) and a newly detected tail, that is to say M 66SE, is found in the southeast of M 66. We suspect that M 66SE represents gas from NGC 3628, which was captured by M 66 in the recent interaction between the two galaxies. Meanwhile gas is falling toward M 66, resulting in features previously observed in the southeastern part of M 66, such as large line widths and double peaks. An upside-down "Y"-shaped H I gas component (M 65S) is detected in the south of M 65, which suggests that M 65 may also have been involved in the interaction. We strongly encourage modern hydrodynamical simulations of this interacting group of galaxies to reveal the origin of the gaseous debris surrounding all three galaxies.

We present the second public data release (DR2) from the DECam Local Volume Exploration survey (DELVE). DELVE DR2 combines new DECam observations with archival DECam data from the Dark Energy Survey, the DECam Legacy Survey, and other DECam community programs. DELVE DR2 consists of similar to 160,000 exposures that cover >21,000 deg(2) of the high-Galactic-latitude ( divide b divide > 10 degrees) sky in four broadband optical/near-infrared filters (g, r, i, z). DELVE DR2 provides point-source and automatic aperture photometry for similar to 2.5 billion astronomical sources with a median 5 sigma point-source depth of g = 24.3, r = 23.9, i = 23.5, and z = 22.8 mag. A region of similar to 17,000 deg(2) has been imaged in all four filters, providing four-band photometric measurements for similar to 618 million astronomical sources. DELVE DR2 covers more than 4 times the area of the previous DELVE data release and contains roughly 5 times as many astronomical objects. DELVE DR2 is publicly available via the NOIRLab Astro Data Lab science platform.

The geosphere of primitive Earth was the source of life's essential building blocks, and the geochemical interactions among chemical elements can inform the origins of biological roles of each element. Minerals provide a record of the fundamental properties that each chemical element contributes to crustal composition, evolution, and subsequent biological utilization. In this study, we investigate correlations between the mineral species and bulk crustal composition of each chemical element. There are statistically significant correlations between the number of elements that each element forms minerals with (#-mineral-elements) and the log of the number of mineral species that each element occurs in, and between #-mineral-elements and the log of the number of mineral localities of that element. There is a lesser correlation between the log of the crustal percentage of each element and #-mineral-elements. In the crustal percentage vs. #-mineral-elements plot, positive outliers have either important biological roles (S, Cu) or toxic biological impacts (Pb, As), while negative outliers have no biological importance (Sc, Ga, Br, Yb). In particular, S is an important bridge element between organic (e.g., amino acids) and inorganic (metal cofactors) biological components. While C and N rarely form minerals together, the two elements commonly form minerals with H, which coincides with the role of H as an electron donor/carrier in biological nitrogen and carbon fixation. Both abundant crustal percentage vs. #-mineral-elements insiders (elements that follow the correlation) and less abundant outsiders (positive outliers from the correlation) have important biological functions as essential structural elements and catalytic cofactors.

This study presents the first large-scale analysis of plant intact glycopeptides. Using wheat germ agglutinin lectin weak affinity chromatography to enrich modified peptides, followed by electron transfer dissociation (ETD)(1) fragmentation tandem mass spectrometry, glycan compositions on over 1100 glycopeptides from 270 proteins found in Arabidopsis inflorescence tissue were characterized. While some sites were only detected with a single glycan attached, others displayed up to 16 different glycoforms. Among the identified glycopeptides were four modified in nonconsensus glycosylation motifs. While most of the modified proteins are secreted, membrane, endoplasmic reticulum (ER), or Golgi-localized proteins, surprisingly, N-linked sugars were detected on a protein predicted to be cytosolic or nuclear.

Brassinosteroid (BR) homeostasis and signaling are crucial for normal growth and development of plants. BR signaling through cell-surface receptor kinases and intracellular components leads to dephosphorylation and accumulation of the nuclear protein BZR1. How BR signaling regulates gene expression, however, remains unknown. Here we show that BZR1 is a transcriptional repressor that has a previously unknown DNA binding domain and binds directly to the promoters of feed back-regulated BR biosynthetic genes. Microarray analyses identified additional potential targets of BZR1 and illustrated, together with physiological studies, that BZR1 coordinates BR homeostasis and signaling by playing dual roles in regulating BR biosynthesis and downstream growth responses.

Mutation of the immunophilin-like FK506-binding protein TWISTED DWARF1 (FKBP42/TWD1) causes dwarf and twisted-organ phenotypes in Arabidopsis. However, the function of FKBP42 is not fully understood at the molecular level. Using genetic, physiological, and immunological experiments, we show here that FKBP42/TWD1 is necessary for brassinosteroid (BR) signal transduction. The twd1 mutant showed reduced BR sensitivity in growth responses and activation of the BZR1 transcription factor. However, twd1 showed normal responses to an inhibitor of BIN2/GSK3, suggesting that twd1 has a defect upstream of BIN2 in the BR signaling pathway. In vitro and in vivo assays showed that TWD1 interacts physically with the kinase domains of the BR receptor kinases BRI1 and BAK1. TWD1 is not required for normal localization of BRI1-GFP to the plasma membrane or for activation of the flagellin receptor kinase FLS2. Our results suggest that FKBP42/TWD1 plays a specific role in the activation of BRI1 receptor

For maintenance of cellular homeostasis, the actions of growth-promoting hormones must be attenuated when nutrient and energy become limiting. The molecular mechanisms that coordinate hormone-dependent growth responses with nutrient availability remain poorly understood in plants [1, 2]. The target of rapamycin (TOR) kinase is an evolutionarily conserved master regulator that integrates nutrient and energy signaling to regulate growth and homeostasis in both animals and plants [3-7]. Here, we show that sugar signaling through TOR controls the accumulation of the brassinosteroid (BR)-signaling transcription factor BZR1, which is essential for growth promotion by multiple hormonal and environmental signals [8-11]. Starvation, caused by shifting of light-grown Arabidopsis seedlings into darkness, as well as inhibition of TOR by inducible RNAi, led to plant growth arrest and reduced expression of BR-responsive genes. The growth arrest caused by TOR inactivation was partially recovered by BR treatment and the gain-of-function mutation bzr1-1D, which causes accumulation of active forms of BZR1 [12]. Exogenous sugar promoted BZR1 accumulation and seedling growth, but such sugar effects were largely abolished by inactivation of TOR, whereas the effect of TOR inactivation on BZR1 degradation is abolished by inhibition of autophagy and by the bzr1-1D mutation. These results indicate that cellular starvation leads sequentially to TOR inactivation, autophagy, and BZR1 degradation. Such regulation of BZR1 accumulation by glucose-TOR signaling allows carbon availability to control the growth promotion hormonal programs, ensuring supply-demand balance in plant growth.

Plant growth is controlled by integration of hormonal and light-signaling pathways. BZS1 is a B-box zinc finger protein previously characterized as a negative regulator in the brassinosteroid (BR)-signaling pathway and a positive regulator in the light-signaling pathway. However, the mechanisms by which BZS1/BBX20 integrates light and hormonal pathways are not fully understood. Here, using a quantitative proteomic workflow, we identified several BZS1-associated proteins, including light-signaling components COP1 and HY5. Direct interactions of BZS1 with COP1 and HY5 were verified by yeast two-hybrid and co-immunoprecipitation assays. Overexpression of BZS1 causes a dwarf phenotype that is suppressed by the hy5 mutation, while overexpression of BZS1 fused with the SRDX transcription repressor domain (BZS1-SRDX) causes a long-hypocotyl phenotype similar to hy5, indicating that BZS1's function requires HY5. BZS1 positively regulates HY5 expression, whereas HY5 negatively regulates BZS1 protein level, forming a feedback loop that potentially contributes to signaling dynamics. In contrast to BR, strigolactone (SL) increases BZS1 level, whereas the SL responses of hypocotyl elongation, chlorophyll and HY5 accumulation are diminished in the BZS1-SRDX seedlings, indicating that BZS1 is involved in these SL responses. These results demonstrate that BZS1 interacts with HY5 and plays a central role in integrating light and multiple hormone signals for photomorphogenesis in Arabidopsis. Copyright (C) 2016, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, and Genetics Society of China. Published by Elsevier Limited and Science Press. All rights reserved.