Chain-growth synthesis of extensively cross-conjugated polyenes
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Global food retail environments are increasingly dominated by large chains and linked to the rising prevalence of obesity
Retail food environments influence food purchasing and dietary patterns. A global analysis of the food retail landscape allowing comparisons across geographical regions is therefore needed to tackle diet-related non-communicable diseases. Here we examine trends in retail food environments from 2009 to 2023 across 97 countries, exploring associations with changes in obesity prevalence. Increases were observed in the density of chain outlets, grocery sales from chain retailers, unhealthy food sales per capita and digital grocery sales; non-chain outlet density and the ratio of non-chain to chain outlets declined over time. South Asia and low- and middle-income countries overall experienced the most rapid transformation. Changes in retail environments and the prevalence of obesity were found to be positively correlated. As retail environments become increasingly digital and dominated by large chains, important implications for diets and health should be expected, particularly in lower-income countries.
Rapid growth rate responses of terrestrial bacteria to field warming on the Antarctic Peninsula
Ice-free terrestrial environments of the western Antarctic Peninsula are expanding and subject to colonization by new microorganisms and plants, which control biogeochemical cycling. Measuring growth rates of microbial populations and ecosystem carbon flux is critical for understanding how terrestrial ecosystems in Antarctica will respond to future warming. We implemented a field warming experiment in early (bare soil; +2 °C) and late (peat moss-dominated; +1.2 °C) successional glacier forefield sites on the western Antarctica Peninsula. We used quantitative stable isotope probing with H218O using intact cores in situ to determine growth rate responses of bacterial taxa to short-term (1 month) warming. Warming increased the growth rates of bacterial communities at both sites, even doubling the number of taxa exhibiting significant growth at the early site. Growth responses varied among taxa. Despite that warming induced a similar response for bacterial relative growth rates overall, the warming effect on ecosystem carbon fluxes was stronger at the early successional site—likely driven by increased activity of autotrophs which switched the ecosystem from a carbon source to a carbon sink. At the late-successional site, warming caused a significant increase in growth rate of many Alphaproteobacteria, but a weaker and opposite gross ecosystem productivity response that decreased the carbon sink—indicating that the carbon flux rates were driven more strongly by the plant communities. Such changes to bacterial growth and ecosystem carbon cycling suggest that the terrestrial Antarctic Peninsula can respond fast to increases in temperature, which can have repercussions for long-term elemental cycling and carbon storage.
Enantioselective synthesis of chiroplasmonic helicoidal nanoparticles by nanoconfinement in chiral dielectric shells
Helicoid metal nanoparticles with intrinsic chirality have unveiled tailorable properties and unlocked many chirality-related applications across various fields. Nevertheless, the existing strategies for enantioselective synthesis of helicoid metal nanoparticles have been predominantly limited to gold. Here, we demonstrate a robust and versatile strategy for the enantioselective synthesis of helicoid nanoparticles beyond gold, leveraging chiral nanoconfinement provided by chiral SiO2 or nanoshells. The chiral nanoconfinement strategy enables the decoupling of ligand-directed crystal growth from chiral induction, allowing for the independent tuning of these two critical aspects. As a result, this approach can not only facilitate the replication of chiral shapes from the chiral nanoshells but also allow the generation of alternative chiral shapes. By employing this approach, we demonstrate the enantioselective synthesis of helicoid Pt, Au@Pt, Au@Pd, Au@Ag, and Au@Cu nanoparticles. The chiroplasmonic properties of Pt- and Pd-based chiral nanoparticles have been discovered, and the inversion of chiroplasmonic properties of Ag-based chiral nanoparticles via facet control has been documented and theoretically explained. The chiral nanoconfinement strategy enriches the toolbox for creating chiral nanoparticles and supports their exploration in diverse applications.
Rapid and sensitive protein complex alignment with Foldseek-Multimer
Advances in computational structure prediction will vastly augment the hundreds of thousands of currently available protein complex structures. Translating these into discoveries requires aligning them, which is computationally prohibitive. Foldseek-Multimer computes complex alignments from compatible chain-to-chain alignments, identified by efficiently clustering their superposition vectors. Foldseek-Multimer is 3–4 orders of magnitudes faster than the gold standard, while producing comparable alignments; this allows it to compare billions of complex pairs in 11 h. Foldseek-Multimer is open-source software available at GitHub via https://github.com/steineggerlab/foldseek/, https://search.foldseek.com/search/ and the BFMD database.
γδ T-cell autoresponses to ectopic membrane proteins: a new type of pattern recognition
T-cell receptor (TCR) γδ-expressing cells are conserved lymphocytes of innate immunity involved in first-line defense and immune surveillance. TCRγδ recognizes protein/nonprotein ligands without the help of the major histocompatibility complex (MHC), especially via direct binding to protein ligands, which is dependent primarily on the δ chain complementary determining region 3 (CDR3δ). However, the mechanism of protein‒antigen recognition by human γδ TCRs remains poorly defined. We hypothesize that γδ TCRs recognize self-proteins expressed ectopically on the cell membrane that are derived from intracellular components under stress. Here, we mapped 16 intercellular self-proteins among 21,000 proteins with a huProteinChip as putative ligands for Vδ1/Vδ2 TCRs, 13 for Vδ1 TCRs and 3 for Vδ2 TCRs. Functional tests confirmed that ectopic nucleolin (NCL) is a ligand for the Vδ1 TCR, whereas protein-glutamine γ-glutamyltransferase K (TGM1) is a ligand for the Vδ2 TCR. In the context of radiation exposure, the ectopic expression of intracellular proteins on the tumor cell surface is related to the increased antitumor cytotoxicity of γδ T cells both in vitro and in vivo. In conclusion, the recognition of intracellular proteins that are ectopically expressed on somatic cells by human γδ TCRs is a basic interaction mechanism that enables new types of immune pattern recognition and a novel γδ TCR-ligand-based strategy for tumor immunotherapy.
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