The maintenance and differentiation of highly potent animal stem cells generates an epigenetic cycle that underlies development. Drosophila female germline stem cells (GSC) produce cystoblast daughters that differentiate into nurse cells and oocytes. Developmental chromatin analysis profiling the differentiation of GSCs into cystoblasts and nCs of increasing ploidy shows that cystoblasts start developing by forming heterochromatin while in a transient syncytial state, the germline cyst, reminiscent of early embryonic cells. The open GSC chromatin state is further restricted by Polycomb repression of targets that include testis expressed genes briefly active in early female germ cells. like other highly potent stem cells, GSC metabolism is reprogrammed and Myc-dependent growth is upregulated by altering mitochondrial membrane transport, gluconeogenesis and other processes. Thus, the animal generational cycle comprises similar but distinct maternal and zygotic stem cell epigenetic cycles. We propose that the pluripotent stem cell state and daughter cell differentiation were shaped by the pressure to resist transposon activity over evolutionary time scales. In this GEO submission, we present data and analyses pertaining to H3K27ac, H3K27me3, and H3K9me3 ChIPseq, ATACseq, and RnAseq of Germline Stem Cells (GSCs) and nurse Cells (nCs) from Drosophila melanogaster ovaries.

Aubrites and enstatite chondrites (ECs) are isotopically similar to the Earth and therefore may resemble the primary materials that accreted to form our planet. Recent bulk H elemental and isotopic analyses of ECs and the Norton County aubrite suggest that enstatite-rich materials are H-rich and may represent a significant source of terrestrial water, with measured values of 3000 & PLUSMN;2000 & mu;g/g H2O and 5300 & PLUSMN;900 & mu;g/g H2O in the bulk and enstatite fractions of Norton County (Piani et al., Science, 2020). Here, we present a detailed investigation of in situ H2O concentrations in enstatite, diopside, forsterite, and plagioclase from a suite of main group aubrites, including Norton County, and Shallowater. We find that enstatite (4 & PLUSMN;2 & mu;g/g H2O), diopside (4.8 & PLUSMN;0.5 & mu;g/g H2O), and forsterite (5 & PLUSMN;3 & mu;g/g H2O) have similar H2O concentrations, and all are significantly lower than plagioclase (24 & PLUSMN;3 & mu;g/g H2O). We combine our in situ analyses of H2O contents with equilibrium partition coefficients and bulk mineralogies to estimate the bulk H2O content of our samples. We compare these first order estimates with bulk volatile analyses conducted using sample pyrolysis and find that the previous bulk H2O analyses of aubrites predominantly reflect terrestrial contamination and alteration. If our conclusion that the reported bulk H2O analyses of Norton County primarily reflect terrestrial contamination and alteration extends to bulk analyses of ECs, then EC-like material may not be a significant source of terrestrial water. Our results support the hypothesis that thermal metamorphism, melting, and differentiation leads to efficient desiccation of planetesimals relative to chondrites, and that differentiated planetesimals contributed, at most, trace amounts to Earth's water budget.& COPY; 2023 Elsevier B.V. All rights reserved.

The dominant benthic primary producers in coral reef ecosystems are complex holobionts with diverse microbiomes and metabolomes. In this study, we characterize the tissue metabolomes and microbiomes of corals, macroalgae, and crustose coralline algae via an intensive, replicated synoptic survey of a single coral reef system (Waimea Bay, OModified Letter Turned Commaahu, Hawaii) and use these results to define associations between microbial taxa and metabolites specific to different hosts. Our results quantify and constrain the degree of host specificity of tissue metabolomes and microbiomes at both phylum and genus level. Both microbiome and metabolomes were distinct between calcifiers (corals and CCA) and erect macroalgae. Moreover, our multi-omics investigations highlight common lipid-based immune response pathways across host organisms. In addition, we observed strong covariation among several specific microbial taxa and metabolite classes, suggesting new metabolic roles of symbiosis to further explore.

AgClO4 has been studied under compression by x-ray diffraction and density functional theory calculations. Experimental evidence of a structural phase transition from the tetragonal structure of AgClO4 to an orthorhombic barite-type structure has been found at 5.1 GPa. The transition is supported by total-energy calculations. In addition, a second transition to a monoclinic structure is theoretically proposed to take place beyond 17 GPa. The equation of state of the different phases is reported as well as the calculated Raman-active phonons and their pressure evolution. Finally, we provide a description of all the structures of AgClO4 and discuss their relationships. The structures are also compared with those of AgCl in order to explain the structural sequence determined for AgClO4.

An unexpected superconductivity enhancement is reported in decompressed In2Se3. The onset of superconductivity in In2Se3 occurs at 41.3 GPa with a critical temperature (T-c) of 3.7 K, peaking at 47.1 GPa. The striking observation shows that this layered chalcogenide remains superconducting in decompression down to 10.7 GPa. More surprisingly, the highest T-c that occurs at lower decompression pressures is 8.2 K, a twofold increase in the same crystal structure as in compression. It is found that the evolution of T-c is driven by the pressure-induced R-3m to I-43d structural transition and significant softening of phonons and gentle variation of carrier concentration combined in the pressure quench. The novel decompression-induced superconductivity enhancement implies that it is possible to maintain pressure-induced superconductivity at lower or even ambient pressures with better superconducting performance.

Yttrium and rare earth elements (REY) in aqueous environments have been intensively studied because they record important geochemical information. For example, the cerium anomaly, measured in marine sedimentary rocks, has been widely applied as a paleoredox indicator. Marine carbonates are the main substrate used to reconstruct REY signal in paleo-oceans with the underlying assumption that REY incorporated into carbonate minerals preserve the authigenic seawater signal. However, extracting authigenic REY signals from carbonate rocks are challenging. It requires dissolving carbonate phases using acid leaching procedures without contamination from other non-carbonate phases such as Mn/Fe oxides (hydroxides), clay minerals, siliciclastic and organic phases. Multiple dissolution protocols, especially partial leaching, were proposed to eliminate potential contaminations. Yet, the efficiency lof these procedures in reducing contamination remains ambiguous. Additionally, no systematic study on how each non-carbonate phase can modify the authigenic REY signal from carbonates. First, we systematically investigated the efficiency of using ammonium acetate buffer pre-treatment to remove exchangeable ions prior to dissolution. We tested a range of concentration, pH, and reaction time of the buffer and we found that ammonium acetate of 1 M with a pH slightly < 7, and 30 mins for reaction time works best for efficiency. Second, we tested a range of acid species and molarity to dissolve common non-carbonate contamination phases including USGS standards NOD-A-1 (manganese nodule) and SBC-1 (Brush Creek shale), as well as montmorillonite, kaolinite, illite from the Clay Minerals Society. We used three batches of acetic and nitric acids with different molarity and found that both the acid species and molarity are key parameters to avoid leaching of non-carbonate phases. We observed a negative Ce anomaly during leaching of Mn nodule using acetic acid versus a positive anomaly using nitric acid suggesting that nitric acid may introduce false positive Ce anomalies into samples. We also demonstrated that it is essential to filter the leachate to prevent the later dissolution of floating particles. For instance, Mn oxides, which carry positive Ce anomalies, can overprint the carbonate REY signal because the nitric acid (i.e. 2% v/v) used during later ICP-MS analysis could dissolve tetravalent Ce. Third, we conducted a series of leaching experiments on mixed samples consisting of 80% pure modern limestone and 20% mixed pure contaminants to identify the best protocol to avoid contamination. We demonstrate that using acetic acid with a molarity lower than 0.5 M is sufficient to avoid contaminations from Mn oxides, clay minerals, and siliciclastic phases. Finally, we present a new sequential leaching protocol for calcite ( > 75% CaCO3) using two steps of ammonium acetate pre-leaching followed by three steps of 0.3 M acetic acid leaching.

In the modern ocean, U reduction and incorporation into anoxic sediments imparts a large isotopic fractionation of approximately vertical bar 0.6 parts per thousand that shifts the seawater delta U-238 value (U-238/U-235, expressed as delta U-238 per mil deviation relative to CRM-112a) relative to continental runoff. Given the long residence time of U in the modern oceans (similar to 400 kyr), the isotopic composition of carbonates (taken as a proxy for seawater) reflects the global balance between anoxic and other sinks. The U isotopic composition of open-marine carbonates has thus emerged as a proxy for reconstructing past changes in the redox state of the global ocean. A tenet of this approach is that the delta U-238 values of seawater and anoxic sediments should always be fractionated by the same amount.