Many proteins regulate the expression of genes by binding to specific regions encoded in the genome
. Here we introduce a new data set of RNA elements in the human genome that are recognized by ...RNA-binding proteins (RBPs), generated as part of the Encyclopedia of DNA Elements (ENCODE) project phase III. This class of regulatory elements functions only when transcribed into RNA, as they serve as the binding sites for RBPs that control post-transcriptional processes such as splicing, cleavage and polyadenylation, and the editing, localization, stability and translation of mRNAs. We describe the mapping and characterization of RNA elements recognized by a large collection of human RBPs in K562 and HepG2 cells. Integrative analyses using five assays identify RBP binding sites on RNA and chromatin in vivo, the in vitro binding preferences of RBPs, the function of RBP binding sites and the subcellular localization of RBPs, producing 1,223 replicated data sets for 356 RBPs. We describe the spectrum of RBP binding throughout the transcriptome and the connections between these interactions and various aspects of RNA biology, including RNA stability, splicing regulation and RNA localization. These data expand the catalogue of functional elements encoded in the human genome by the addition of a large set of elements that function at the RNA level by interacting with RBPs.
The last 2500 years of activity at Kīlauea Volcano (Hawai‘i) have been characterized by centuries-long periods dominated by either effusive or explosive eruptions. The most recent period of explosive ...activity produced the Keanakāko‘i Tephra (KT; ca. 1500–1820 C.E.) and occurred after the collapse of the summit caldera (1470–1510 C.E.). Previous studies suggest that KT magmas may have ascended rapidly to the surface, bypassing storage in crustal reservoirs. The storage conditions and rapid ascent hypothesis are tested here using chemical zoning in olivine crystals and thermodynamic modeling. Forsterite contents (Fo; Mg/(Mg + Fe) × 100) of olivine core and rim populations are used to identify melt components in Kīlauea’s prehistoric (i.e., pre-1823) plumbing system. Primitive (≥Fo
88
) cores occur throughout the 300+ years of the KT period; they originated from mantle-derived magmas that were first mixed and stored in a deep crustal reservoir. Bimodal olivine populations (≥Fo
88
and Fo
83–84
) record repeated mixing of primitive magmas and more differentiated reservoir components shallower in the system, producing a hybrid composition (Fo
85–87
). Phase equilibria modeling using MELTS shows that liquidus olivine is not stable at depths >17 km. Thus, calculated timescales likely record mixing and storage within the crust. Modeling of Fe–Mg and Ni zoning patterns (normal, reverse, complex) reveal that KT magmas were mixed and stored for a few weeks to several years before eruption, illustrating a more complex storage history than direct and rapid ascent from the mantle as previously inferred for KT magmas. Complexly zoned crystals also have smoothed compositional reversals in the outer 5–20 µm rims that are out of Fe–Mg equilibrium with surrounding glasses. Diffusion models suggest that these rims formed within a few hours to a few days, indicating that at least one additional, late-stage mixing event may have occurred shortly prior to eruption. Our study illustrates that the lifetimes of KT magmas are more complex than previously proposed, and that most KT magmas did not rise rapidly from the mantle without modification during shallow crustal storage.
Kauaʻi shield‐stage lavas are central to understanding the origin of the distinct Kea and Loa Hawaiian geochemical trends in Hawaiian basalts. These trends reflect two geochemically distinct sides in ...the Hawaiian plume, with Loa to the southwest and Kea to the northeast. The geochemistry and Sr‐Nd‐Hf isotopic compositions of shield‐stage lavas from Kauaʻi show a transition from Kea to Loa across the island with the Loa mantle source becoming dominant as the volcano grew. This geochemical transition is gradual from west to east Kauaʻi and supports the hypothesis that the Kauaʻi volcano sampled both sides of the bilateral Hawaiian plume, a phenomenon that is unusual for a Hawaiian volcano. Notably, Kauaʻi marks the arrival of progressively larger volumes of Loa compositions within the Hawaiian mantle plume. The new data from Kauaʻi, combined with an updated and comprehensive database of Hawaiian shield‐stage major element oxides, trace element concentrations, and isotopic compositions normalized to the same standard values, allows for the Pb‐Sr‐Nd‐Hf isotopic compositions of the Average Loa (‘ALOA’) common geochemical component to be estimated. Despite the bilateral Loa‐Kea geochemical trend beginning at Molokaʻi, Loa compositions dominate the erupted volume of Hawaiian volcanoes younger than 3 Ma, validating the volumetric importance of the Loa source in the lower mantle portion of the Hawaiian plume.
Plain Language Summary
Hawaiian volcanoes are arranged along two parallel geographic trends named Loa and Kea. Volcanoes belonging to either trend have distinct geochemical compositions that are linked to their deep mantle sources as sampled by the Hawaiian mantle plume. The Kea composition has been present in shield‐stage basalts for ∼81 Ma, however the Loa composition is relatively new and has mainly been measured in volcanoes formed since 3–4 Ma. We used the geochemistry and isotopic compositions of shield‐stage basalts from the island of Kauaʻi to show that Loa compositions began to appear in larger amounts in the Hawaiian plume around 5 Ma. These new data, combined with a large and carefully curated geochemical data set of Hawaiian samples, has allowed us to estimate the average composition of Loa and its associated isotopic end‐member compositions. This work demonstrates that Loa was an important mantle source for the older Hawaiian volcanoes such as Kauaʻi and dominates shield lavas along the Hawaiian chain. Notably, the geochemistry of Kauaʻi’s volcanic rocks represents the long‐term establishment of Loa compositions in the Hawaiian plume.
Key Points
Radiogenic (Sr‐Nd‐Hf, and Pb) isotopic compositions change from west to east across Kauaʻi and broadly correlate with age
Kauaʻi records the first large‐scale and long‐lasting occurrence of Loa‐trend Hawaiian compositions
The average Loa composition is constrained in Pb‐Sr‐Nd‐Hf isotopes and dominates compositions along the Hawaiian chain
We report here the first occurrence of celestine (SrSO4) in recent oceanic basalts. Celestine was found in moderately altered accidental volcanic blocks from Ka'ula Island, a rejuvenated tuff cone in ...the northern Hawaiian Islands. This occurrence is novel not only for the presence of celestine but also for the absence of barite, the sulfate mineral most commonly found in oceanic hydrothermal deposits. Celestine was found lining vesicles and partially fillings voids within the matrix of several high Sr (2200-6400 ppm) Ka'ula basalts. High-quality wavelength-dispersive microprobe analyses of celestine are reported here for near end-member celestine (>90%). The Ka'ula celestine deposits are compositionally heterogeneous with large variations in Ba content (0.9-7.5 wt%) within single mineral aggregates. The most likely source of the Sr for celestine in the Ka'ula basalts was the host basalt, which contains ∼1200 ppm. This is about 10 times higher than normally found in mid-ocean ridge basalts and 4 times greater than commonly observed in Hawaiian basalts. Hydrothermal alteration by S-bearing fluids related to the eruption that transported these accidentally fragments probably mobilized Sr in the blocks. These S-rich solutions later precipitated celestine during or following the eruption. We were unable to confirm the origin for the Sr via Sr isotope measures because the Ka'ula celestine was too fine grained, friable, and widely dispersed to be concentrated for Sr isotope analyses. Future studies of basalts from active volcanoes on oceanic islands, especially for basalts with elevated Sr contents (>1000 ppm), should be aware of the possible presence of celestine in moderately altered lavas.
To describe the outcomes of hospitalized patients in a multicenter, international coronavirus disease 2019 registry.
Cross-sectional observational study including coronavirus disease 2019 patients ...hospitalized with laboratory-confirmed severe acute respiratory syndrome coronavirus-2 infection between February 15, 2020, and November 30, 2020, according to age and type of organ support therapies.
About 168 hospitals in 16 countries within the Society of Critical Care Medicine's Discovery Viral Infection and Respiratory Illness University Study coronavirus disease 2019 registry.
Adult hospitalized coronavirus disease 2019 patients who did and did not require various types and combinations of organ support (mechanical ventilation, renal replacement therapy, vasopressors, and extracorporeal membrane oxygenation).
None.
Primary outcome was hospital mortality. Secondary outcomes were discharge home with or without assistance and hospital length of stay. Risk-adjusted variation in hospital mortality for patients receiving invasive mechanical ventilation was assessed by using multilevel models with hospitals as a random effect, adjusted for age, race/ethnicity, sex, and comorbidities. Among 20,608 patients with coronavirus disease 2019, the mean (± sd) age was 60.5 (±17), 11,1887 (54.3%) were men, 8,745 (42.4%) were admitted to the ICU, and 3,906 (19%) died in the hospital. Hospital mortality was 8.2% for patients receiving no organ support (n = 15,001). The most common organ support therapy was invasive mechanical ventilation (n = 5,005; 24.3%), with a hospital mortality of 49.8%. Mortality ranged from 40.8% among patients receiving only invasive mechanical ventilation (n =1,749) to 71.6% for patients receiving invasive mechanical ventilation, vasoactive drugs, and new renal replacement therapy (n = 655). Mortality was 39% for patients receiving extracorporeal membrane oxygenation (n = 389). Rates of discharge home ranged from 73.5% for patients who did not require organ support therapies to 29.8% for patients who only received invasive mechanical ventilation, and 8.8% for invasive mechanical ventilation, vasoactive drugs, and renal replacement; 10.8% of patients older than 74 years who received invasive mechanical ventilation were discharged home. Median hospital length of stay for patients on mechanical ventilation was 17.1 days (9.7-28 d). Adjusted interhospital variation in mortality among patients receiving invasive mechanical ventilation was large (median odds ratio 1.69).
Coronavirus disease 2019 prognosis varies by age and level of organ support. Interhospital variation in mortality of mechanically ventilated patients was not explained by patient characteristics and requires further evaluation.
An ongoing challenge in studies of the oceanic upper mantle is how intraplate hotspots impact the thermal structure of the lithosphere. To address this issue at the Hawaiian hotspot, we analyze ...mineral compositions for a petrographically diverse suite of garnet pyroxenite xenoliths from the Salt Lake Crater (SLC) rejuvenation stage, volcanic tuff ring in Honolulu. Garnet‐clinopyroxene geobarometry and two‐pyroxene geothermometry indicate equilibrium pressures of 13–18 kbar and temperatures of 1000°C–1100°C. These pressures place the xenoliths at mid‐lithospheric depths of 45–55 km, with temperatures 200°C–300°C hotter than expected for normal 90‐Myr‐old oceanic lithosphere. Garnet and clinopyroxene occur as discrete primary grains, as well as exsolution blebs and lamellae, with lateral dimensions up to several hundred microns. Compositions within garnet and pyroxene grains are remarkably uniform and display no systematic variation with distance to grain boundaries. Together, these observations indicate that the calculated pressures and temperatures reflect the thermal state of the lithosphere under which the xenoliths last equilibrated. We attribute the elevated lithospheric temperatures under Honolulu primarily to the heating by magma as it penetrated the lithosphere during rejuvenation magmatism and the voluminous shield magmatic stage. We anticipate such magmatic heating to be common among all Hawaiian volcanoes, supporting conclusions of a recent study of earthquakes beneath Hawai‘i Island. This local lithospheric thermal anomaly may also contribute to the enigmatically weak flexural response of the lithosphere due to volcano loading along the Hawaiian hotspot chain.
Plain Language Summary
The Hawaiian‐Emperor volcano chain in the Pacific Ocean is one of the most well‐known surface expressions of a mantle hotspot, having persisted over the past 82 Myrs. This continued influx of magma and heat has impacted the thermal structure of the Pacific tectonic plate to an unknown degree. This study directly addresses this issue using rocks (xenoliths) that originated in the lithospheric plate, but became engulfed in magma as it passed through the plate and eventually erupted at Salt Lake Crater, a late‐stage volcanic ring tuff on the island of O‘ahu. We use the chemical compositions of the minerals, as well as their modes of occurrence found in the mantle xenoliths to calculate the temperatures and pressures (i.e., depths) at which the xenoliths equilibrated. We find that the xenoliths equilibrated at depths where temperature was significantly higher than expected for normal oceanic lithosphere having the same age as the Hawaiian lithosphere. We infer that these anomalous temperatures were introduced by magma that rose from the hot mantle through the lithospheric plate during the volcanic construction of the island of O‘ahu. Such magmatic heating may impact how the plate flexes and faults due to the enormous weight of this and the other Hawaiian volcanoes.
Key Points
Revised geothermometer and new geobarometer calculations place the xenoliths at mid‐lithospheric depths of 45–55 km
The temperatures at these depths are 200°C–300°C warmer than expected for normal lithosphere beneath 90‐Myr‐old seafloor
The adjacent lithosphere is inferred to have been reheated rapidly during the voluminous Ko'olau shield volcano magmatism
The deep mantle carbon content and flux are fundamental quantities in understanding global volatile cycles and distributions. Here, we present CO2 concentrations measured in 407 olivine-hosted melt ...inclusions from Hualalai, Kilauea, Koolau, Loihi, and Mauna Loa to constrain the Hawaiian mantle CO2 content and flux. Quantification of melt inclusion CO2 is complicated by the ubiquitous presence of vapor or “shrinkage” bubbles. The contribution from exsolved shrinkage bubble CO2 was determined from the measured bubble size and a CO2 equation of state, and added to the dissolved CO2 to reconstruct total melt inclusion CO2 concentrations. Bubbles typically contain ∼90% of melt inclusion C, much of which may be sequestered in precipitated phases on bubble walls, and thus not amenable to measurement by Raman spectroscopy. Based on our dataset of total (dissolved + bubble) CO2 concentrations, we estimate that parental melts from the five Hawaiian volcanoes have CO2 concentrations ranging from 3900 to 10,000 ppm CO2. Among the active volcanoes, CO2 concentrations decrease to the northwest, likely reflecting mantle source heterogeneity, although differences in CO2 degassing related to the relative depths of the magma chambers may also play a role. Mantle sources of the Hawaiian volcanoes range from 380 to 480 ppm CO2 suggesting that the Hawaiian plume is at least a factor of ∼4 more C-rich than the upper mantle sampled by mid-ocean ridge basalts. This enrichment is likely due to the presence of recycled surficial C and/or C-rich primitive material in the Hawaiian mantle.
Photocatalytic hydrogen atom transfer is a very powerful strategy for the regioselective C(sp3)–H functionalization of organic molecules. Herein, we report on the unprecedented combination of ...decatungstate hydrogen atom transfer photocatalysis with the oxidative radical–polar crossover concept to access the direct net‐oxidative C(sp3)–H heteroarylation. The present methodology demonstrates a high functional group tolerance (40 examples) and is scalable when using continuous‐flow reactor technology. The developed protocol is also amenable to the late‐stage functionalization of biologically relevant molecules such as stanozolol, (−)‐ambroxide, podophyllotoxin, and dideoxyribose.
The combination of decatungstate photocatalysis with oxidative radical–polar crossover is reported. This strategy enables the C(sp3)–H heteroarylation under mild conditions with excellent functional group tolerance. It was also adopted to enable late‐stage functionalization of valuable compounds. Microflow technology reduced reaction times and boosted productivity of the transformation.
Olivine in Hawaiian tholeiitic lavas have high NiO at given forsterite (Fo) contents (e.g., 0.25-0.60 wt% at Fo88) compared to MORB (e.g., 0.10-0.28 wt% at Fo88). This difference is commonly related ...to source variables such as depth and temperature of melting and/or lithology. Hawaiian olivine NiO contents are also highly variable and can range from 0.25-0.60 wt% at a given Fo. Here we examine the effects of crustal processes (fractional crystallization, magma mixing, diffusive re-equilibration) on the Ni content in olivine from Hawaiian basalts. Olivine compositions for five major Hawaiian volcanoes can be subdivided at ≥Fo88 into high-Ni (0.25-0.60 wt% NiO; Ko'olau, Mauna Loa, and Mauna Kea) and low-Ni (0.25-0.45 wt% NiO; Kilauea and Lo'ihi), groups that are unrelated to major isotopic trends (e.g., Loa and Kea). Within each group, individual volcanoes show up to 2.5× variation in olivine NiO contents at a given Fo. Whole-rock Ni contents from Ko'olau, Mauna Loa, Mauna Kea, and Kilauea lavas overlap significantly and do not correlate with differences in olivine NiO contents. However, inter-volcano variations in parental melt polymerization (NBO/T) and nickel partition coefficients (DNiOl/melt), caused by variable melt SiO2, correlate with observed differences in olivine NiO at Fo90, indicating that an olivine-free source lithology does not produce the inter-volcano groups. Additionally, large intra-volcano variations in olivine NiO can occur with minimal variation in lava SiO2 and NBO/T. Minor variations in parental melt NiO contents (0.09-0.11 wt%) account for the observed range of NiO in ≥Fo88 olivine. High-precision electron microprobe analyses of olivine from Kilauea eruptions (1500-2010 C.E.) show that the primary controls on <Fo88 olivine NiO contents are fractional crystallization, magma mixing, and diffusive re-equilibration. Core-rim transects of normally zoned olivine crystals reveal marked differences in Fo and NiO zoning patterns that cannot be related solely to fractional crystallization. These Fo-NiO profiles usually occur in olivine with <Fo88 and are common in mixed magmas, although they are not restricted to lavas with obvious petrographic signs of mixing. Three-dimensional numerical diffusion models show that diffusive re-equilibration decouples the growth zoning signatures of faster diffusing Fe-Mg (Fo) from the somewhat slower Ni. This diffusive "decoupling" overprints the chemical relationships of Fe-Mg, Ni, and Mn inherited from crystal growth and influences the calculated fraction of pyroxenite-derived melt (Xpx). Sections of numerical olivine that have been affected by diffusive re-equilibration indicate that larger phenocrysts (800 µm along c-axis) are >50% more likely to preserve original Xpx compared to smaller phenocrysts (400 µm along c-axis) which rarely (6%) recover original Xpx. Sections that are parallel or sub-parallel to the c-axis and/or pass near the core of the crystal best preserve growth signatures. Thus, diffusive re-equilibration, crystal size, and sectioning effects can strongly influence the characterization of mantle source lithologies for Hawaiian volcanoes.
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