Proposals for achieving net-zero emissions by 2050 include scaling-up electrolytic hydrogen production, however, this poses technical, economic, and environmental challenges. One such challenge is for policymakers to ensure a sustainable future for the environment including freshwater and land resources while facilitating low-carbon hydrogen production using renewable wind and solar energy. We establish a country-by-country reference scenario for hydrogen demand in 2050 and compare it with land and water availability. Our analysis highlights countries that will be constrained by domestic natural resources to achieve electrolytic hydrogen self-sufficiency in a net-zero target. Depending on land allocation for the installation of solar panels or wind turbines, less than 50% of hydrogen demand in 2050 could be met through a local production without land or water scarcity. Our findings identify potential importers and exporters of hydrogen or, conversely, exporters or importers of industries that would rely on electrolytic hydrogen. The abundance of land and water resources in Southern and Central-East Africa, West Africa, South America, Canada, and Australia make these countries potential leaders in hydrogen export.

Isotopic studies of meteorites suggest that planetesimals were formed as two distinct populations: noncarbonaceous (NC) and carbonaceous (CC) reservoirs. A recent model explains this dichotomy by considering planetesimal formation at the snowline during its migration in the protoplanetary disk, suggesting that NC planetesimals were formed during the outward migration and CC planetesimals were formed during the inward migration. This model has been suggested to contradict meteorite observations because planetesimals formed at the snowline are expected to be rich in H2O and, therefore, develop more oxidizing environments than those inferred from NC iron meteorites. However, if the accreted ice sublimates into vapor without transitioning into a liquid state, the planetesimals may lose most water without being oxidized because reactions between vapor and solids are negligibly slow at temperatures relevant to direct ice sublimation. Here, we investigate the transport of vapor inside a planetesimal and suggest that the pore pressure would have been sufficiently low for direct ice sublimation if (1) the planetesimals were formed during the outward snowline migration (such that they lay inside the snowline after formation and had surfaces permeable to water vapor), (2) these planetesimals were formed by dust-aggregate boulders through "streaming instabilities" instead of being formed directly by submicrometer dust grains, and (3) the boulders were between a few centimeters to similar to 10 m in size. With these results, the snowline model for NC/CC planetesimal formation may be reconciled with the observations of iron meteorite oxidation states.

Zebrafish are an ideal model organism to study lipid metabolism and to elucidate the molecular underpinnings of human lipid-associated disorders. In this study, we provide an improved protocol to assay the impact of a high-cholesterol diet (HCD) on zebrafish lipid deposition and lipoprotein regulation. Fish fed HCD developed hypercholesterolemia as indicated by significantly elevated ApoB-containing lipoproteins (ApoB-LP) and increased plasma levels of cholesterol and cholesterol esters. Feeding of the HCD to larvae (8 days followed by a 1 day fast) and adult female fish (2 weeks, followed by 3 days of fasting) was also associated with a fatty liver phenotype that presented as severe hepatic steatosis. The HCD feeding paradigm doubled the levels of liver triacylglycerol (TG), which was striking because our HCD was only supplemented with cholesterol. The accumulated liver TG was unlikely due to increased de novo lipogenesis or inhibited -oxidation since no differentially expressed genes in these pathways were found between the livers of fish fed the HCD versus control diets. However, fasted HCD fish had significantly increased lipogenesis gene fasn in adipose tissue and higher free fatty acids (FFA) in plasma. This suggested that elevated dietary cholesterol resulted in lipid accumulation in adipocytes, which supplied more FFA during fasting, promoting hepatic steatosis. In conclusion, our HCD zebrafish protocol represents an effective and reliable approach for studying the temporal characteristics of the physiological and biochemical responses to high levels of dietary cholesterol and provides insights into the mechanisms that may underlie fatty liver disease.

BRASSINAZONE RESISTANT 1 (BZR1) is a key transcription factor of the brassinosteroid signaling pathway but also a signaling hub that integrates diverse signals that modulate plant growth. Previous studies have shown that starvation causes BZR1 degradation, but the underlying mechanisms are not understood. Here we performed quantitative proteomic analysis of BZR1 interactome under starvation conditions and identified two BZR1-interacting ubiquitin ligases, BAF1 and UPL3. Compared to the wild type, the upl3 mutants show long hypocotyl and increased BZR1 levels when grown under sugar starvation conditions but not when grown on sugar-containing media, indicating a role of UPL3 in BZR1 degradation specifically under starvation conditions. The upl3 mutants showed a reduced survival rate after starvation treatment, supporting the importance of UPL3-mediated BZR1 degradation and growth arrest for starvation survival. Treatments with inhibitors of TARGET of RAPAMYCIN and autophagy altered BZR1 level in the wild type but were less effective in upl3, suggesting that UPL3 mediates the TOR-regulated and autophagy-dependent degradation of BZR1. Further, the UPL3 protein level is increased posttranscriptionally by starvation but decreased by sugar treatment. Our study identifies UPL3 as a key component that mediates sugar regulation of hormone signaling pathways, important for optimal growth and survival in plants.

There is concern that the time taken to publish academic papers in microbiological science has significantly increased in recent years. While the data do not specifically support this, evidence suggests that editors are having to invite more and more reviewers to identify those willing to perform peer review.

Subduction related to the ancient supercontinent cycle is poorly constrained by mantle samples. Sublithospheric diamond crystallization records the release of melts from subducting oceanic lithosphere at 300-700 km depths(1,2) and is especially suited to tracking the timing and effects of deep mantle processes on supercontinents. Here we show that four isotope systems (Rb-Sr, Sm-Nd, U-Pb and Re-Os) applied to Fe-sulfide and CaSiO3 inclusions within 13 sublithospheric diamonds from Juina (Brazil) and Kankan (Guinea) give broadly overlapping crystallization ages from around 450 to 650 million years ago. The intracratonic location of the diamond deposits on Gondwana and the ages, initial isotopic ratios, and trace element content of the inclusions indicate formation from a peri-Gondwanan subduction system. Preservation of these Neoproterozoic-Palaeozoic sublithospheric diamonds beneath Gondwana until its Cretaceous breakup, coupled with majorite geobarometry(3,4,) suggests that they accreted to and were retained in the lithospheric keel for more than 300 Myr during supercontinent migration. We propose that this process of lithosphere growth-with diamonds attached to the supercontinent keel by the diapiric uprise of depleted buoyant material and pieces of slab crust-could have enhanced supercontinent stability.

Animal regeneration requires coordinated responses of many cell types throughout the animal body. In animals carrying endosymbionts, cells from the other species may also participate in regeneration, but how cellular responses are integrated across species is yet to be unraveled. Here, we study the acoel Convolutriloba longifissura, which hosts symbiotic Tetraselmis green algae and can regenerate entire bodies from small tissue fragments. We show that animal injury leads to a decline in the photosynthetic efficiency of the symbiotic algae and concurrently induces upregulation of a cohort of photosynthesis-related genes. A deeply conserved animal transcription factor, runt, is induced after injury and required for the acoel regeneration. Knockdown of runt also dampens algal transcriptional responses to the host injury, particularly in photosynthesis related pathways, and results in further reduction of photosynthetic efficiency post-injury. Our results suggest that the runt-dependent animal regeneration program coordinates wound responses across the symbiotic partners and regulates photosynthetic carbon assimilation in this metaorganism.