The geological units on the floor of Jezero crater, Mars, are part of a wider regional stratigraphy of olivine-rich rocks, which extends well beyond the crater. We investigated the petrology of olivine and carbonate-bearing rocks of the Seitah formation in the floor of Jezero. Using multispectral images and x-ray fluorescence data, acquired by the Perseverance rover, we performed a petrographic analysis of the Bastide and Brac outcrops within this unit. We found that these outcrops are composed of igneous rock, moderately altered by aqueous fluid. The igneous rocks are mainly made of coarsegrained olivine, similar to some martian meteorites. We interpret them as an olivine cumulate, formed by settling and enrichment of olivine through multistage cooling of a thick magma body.

Northwest China has experienced a warming-wetting climate featured by increasing temperature and precipitation during the past six decades. Recent studies suggested that the climate may have shifted from wetting to drying after the 1990s if changes in energy supply were considered. However, how the change in energy supply affects the dryness remains unclear. In this study, we quantified the dryness in Northwest China based on the Standardized Precipitation Evapotranspiration Index (SPEI) which considers the impact of potential evapotranspiration estimated by the Penman-Monteith equation on dryness during 1961-2018. Then, the contributions of changes in meteorological variables (precipitation, temperature, relative humidity, wind speed, and net radiation) to the dryness changes were estimated using a detrending technique. The results indicated that Northwest China experienced a wetting period (1961-1989) and then a drying period (1989-2018). During 1961-1989, increased precipitation and slowed wind were the main drivers of the wetting trend. During 1989-2018, although the increased precipitation and decline in solar radiation favored a wetting condition, warmer temperature, drier air (decrease in relative humidity), together with rebounded wind speed offset the wetting trend and resulted in significantly increasing dryness in Northwest China. The dryness would further increase if current climate trends continue in the future, which may have important implications for water management in Northwest China.

The identification of factors that may be forcing ecological observations to approach the upper boundary provides insight into potential mechanisms affecting driver-response relationships, and can help inform ecosystem management, but has rarely been explored. In this study, we propose a novel framework integrating quantile regression with interpretable machine learning. In the first stage of the framework, we estimate the upper boundary of a driver-response relationship using quantile regression. Next, we calculate "potentials " of the response variable depending on the driver, which are defined as vertical distances from the estimated upper boundary of the relationship to observations in the driver-response variable scatter plot. Finally, we identify key factors impacting the potential using a machine learning model. We illustrate the necessary steps to implement the framework using the total phosphorus (TP)-Chlorophyll a (CHL) relationship in lakes across the continental US. We found that the nitrogen to phosphorus ratio (N:P), annual average precipitation, total nitrogen (TN), and summer average air temperature were key factors impacting the potential of CHL depending on TP. We further revealed important implications of our findings for lake eutrophication management. The important role of N:P and TN on the potential highlights the co-limitation of phosphorus and nitrogen and indicates the need for dual nutrient criteria. Future wetter and/or warmer climate scenarios can decrease the potential which may reduce the efficacy of lake eutrophication management. The novel framework advances the application of quantile regression to identify factors driving observations to approach the upper boundary of driver-response relationships.

The clinical and largely unpredictable heterogeneity of phenotypes in patients with mitochondrial disorders demonstrates the ongoing challenges in the understanding of this semi-autonomous organelle in biology and disease. Previously, we used the gene-breaking transposon to create 1200 transgenic zebrafish strains tagging protein-coding genes (Ichino et al., 2020), including the lrpprc locus. Here, we present and characterize a new genetic revertible animal model that recapitulates components of Leigh Syndrome French Canadian Type (LSFC), a mitochondrial disorder that includes diagnostic liver dysfunction. LSFC is caused by allelic variations in the LRPPRC gene, involved in mitochondrial mRNA polyadenylation and translation. lrpprc zebrafish homozygous mutants displayed biochemical and mitochondrial phenotypes similar to clinical manifestations observed in patients, including dysfunction in lipid homeostasis. We were able to rescue these phenotypes in the disease model using a liver-specific genetic model therapy, functionally demonstrating a previously under-recognized critical role for the liver in the pathophysiology of this disease.

The thermal equation of states for fcc iridium (Ir) is obtained from first-principles molecular dynamics up to 3000 K and 540 GPa. The equation of state (EoS) is globally fitted to a simplified free-energy model and various parameters are derived. The theoretical principal Hugoniot is compared with shock wave experiments, where discrepancy suggests formation of new Ir phases. A few representative EoS parameters, such as bulk modulus KT, thermal expansivity alpha, Gruneisen parameter gamma, constant pressure capacity CP, and Debye temperature OD, are computed to compare with experimental data.

The recent discovery of SPINDLY (SPY)-catalyzed protein O-fucosylation revealed a novel mechanism for regulating nucleocytoplasmic protein functions in plants. Genetic evidence indicates the important roles of SPY in diverse developmental and physiological processes. However, the upstream signal controlling SPY activity and the downstream substrate proteins O-fucosylated by SPY remain largely unknown. Here, we demonstrated that SPY mediates sugar-dependent growth in Arabidopsis (Arabidopsis thaliana). We further identified hundreds of O-fucosylated proteins using lectin affinity chromatography followed by mass spectrometry. All the O-fucosylation events quantified in our proteomic analyses were undetectable or dramatically decreased in the spy mutants, and thus likely catalyzed by SPY. The O-fucosylome includes mostly nuclear and cytosolic proteins. Many O-fucosylated proteins function in essential cellular processes, phytohormone signaling, and developmental programs, consistent with the genetic functions of SPY. The O-fucosylome also includes many proteins modified by O-linked N-acetylglucosamine (O-GlcNAc) and by phosphorylation downstream of the target of rapamycin (TOR) kinase, revealing the convergence of these nutrient signaling pathways on key regulatory functions such as post-transcriptional/translational regulation and phytohormone responses. Our study identified numerous targets of SPY/O-fucosylation and potential nodes of crosstalk among sugar/nutrient signaling pathways, enabling future dissection of the signaling network that mediates sugar regulation of plant growth and development.

The commonalities and convergences shared in apicomplexans and dinoflagellates are continually becoming more andmore apparent, yet researchers across this myzozoan supergroup seldommeet at scientificmeetings. The Conference Jacques Monod meeting entitled `From Parasites to Plankton and Back: Comparative Biology and Ecology of Apicomplexans and Dinoflagellates' sought to change this. Held at the RoscoffMarine Station in France on September 5-9, 2022, researchers spanning organisms, disciplines, and perspectives met to immerse themselves in the latest developments and discoveries across the group. The outcome was an exciting and stimulating view of the synergies, revelations, and opportunities enabled by expanding one's view and network across this vast, spectacular and important biological group. In this TrendsTalk, the conference organizers and several young researchers present a synthesis of the key outcomes of this meeting of minds and biology.

Saturn's moon Enceladus has a potentially habitable subsurface water ocean that contains canonical building blocks of life (organic and inorganic carbon, ammonia, possibly hydrogen sulfide) and chemical energy (disequilibria for methanogenesis). However, its habitability could be strongly affected by the unknown availability of phosphorus (P). Here, we perform thermodynamic and kinetic modeling that simulates P geochemistry based on recent insights into the geochemistry of the ocean-seafloor system on Enceladus. We find that aqueous P should predominantly exist as orthophosphate (e.g., HPO42-), and total dissolved inorganic P could reach 10(-7) to 10(-2) mol/kg H2O, generally increasing with lower pH and higher dissolved CO2, but also depending upon dissolved ammonia and silica. Levels are much higher than <10210 mol/kg H2O from previous estimates and close to or higher than similar to 10(-6) mol/kg H2O in modern Earth seawater. The high P concentration is primarily ascribed to a high (bi)carbonate concentration, which decreases the concentrations of multivalent cations via carbonate mineral formation, allowing phosphate to accumulate. Kinetic modeling of phosphate mineral dissolution suggests that geologically rapid release of P from seafloor weathering of a chondritic rocky core could supply millimoles of total dissolved P per kilogram of H2O within 10(5) y, much less than the likely age of Enceladus's ocean (10(8) to 10(9) y). These results provide further evidence of habitable ocean conditions and show that any oceanic life would not be inhibited by low P availability.

Carbon dioxide (CO2) is a key chemical species that is found in a wide range of planetary atmospheres. In the context of exoplanets, CO2 is an indicator of the metal enrichment (that is, elements heavier than helium, also called 'metallicity')(1-3), and thus the formation processes of the primary atmospheres of hot gas giants(4-6). It is also one of the most promising species to detect in the secondary atmospheres of terrestrial exoplanets(7-9). Previous photometric measurements of transiting planets with the Spitzer Space Telescope have given hints of the presence of CO2, but have not yielded definitive detections owing to the lack of unambiguous spectroscopic identification(10-12). Here we present the detection of CO2 in the atmosphere of the gas giant exoplanet WASP-39b from transmission spectroscopy observations obtained with JWST as part of the Early Release Science programme(13,14). The data used in this study span 3.0-5.5micrometres in wavelength and show a prominent CO2 absorption feature at 4.3micrometres (26-sigma significance). The overall spectrum is well matched by one-dimensional, ten-times solar metallicity models that assume radiative-convective-thermochemical equilibrium and have moderate cloud opacity. These models predict that the atmosphere should have water, carbon monoxide and hydrogen sulfide in addition to CO2, but little methane. Furthermore, we also tentatively detect a small absorption feature near 4.0micrometres that is not reproduced by these models.

Samples of the carbonaceous asteroid (162173) Ryugu were collected and brought to Earth by the Hayabusa2 spacecraft. We investigated the macromolecular organic matter in Ryugu samples and found that it contains aromatic and aliphatic carbon, ketone, and carboxyl functional groups. The spectroscopic features of the organic matter are consistent with those in chemically primitive carbonaceous chondrite meteorites that experienced parent-body aqueous alteration (reactions with liquid water). The morphology of the organic carbon includes nanoglobules and diffuse carbon associated with phyllosilicate and carbonate minerals. Deuterium and/or nitrogen-15 enrichments indicate that the organic matter formed in a cold molecular cloud or the presolar nebula. The diversity of the organic matter indicates variable levels of aqueous alteration on Ryugu's parent body.