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Reply to Lü: Aerophilic interfaces across scales
GPIHBP1 on oligodendrocytes binds lipoprotein lipase within the human brain
In peripheral tissues, lipoprotein lipase (LPL) is secreted by parenchymal cells (adipocytes, myocytes) into the interstitial spaces, where it is captured by GPIHBP1 (a glycosylphosphatidylinositol-anchored protein of capillary endothelial cells) and escorted to the luminal surface of capillaries. The LPL inside capillaries hydrolyzes glycerolipids in the plasma lipoproteins, releasing fatty acids for parenchymal cells. In the central nervous system, LPL is synthesized by multiple cell types [e.g., microglia, oligodendrocyte precursor cells (OPCs)] and secreted into the interstitium, but a binding site for the LPL has never been identified. By examining single nuclei RNA-seq databases of the human brain, we found that GPIHBP1 is expressed by oligodendrocytes but not by OPCs. This gene-expression profile (high in oligodendrocytes, low in OPCs) is also observed in genes for myelin structural proteins, fatty acid binding and transport proteins, and lipid biosynthetic enzymes. GPIHBP1 expression in oligodendrocytes was confirmed by in situ hybridization studies of human brain and by immunohistochemical staining. Of note, GPIHBP1 and LPL are colocalized on oligodendrocytes in the human brain. Our findings identify GPIHBP1 as a principal binding site for interstitial LPL in the human brain and suggest that GPIHBP1-bound LPL could hydrolyze interstitial lipids and thereby supply oligodendrocytes with fatty acid nutrients.
Damselflies overcome color saturation barriers of photonic glasses via pigment loading and refractive index modulation
Biological strategies for manipulating light have revealed new concepts in light scattering, inspiring the design of sustainable photonic materials. While iridescent optical systems have been extensively studied, many applications require noniridescent structural colors which are much more difficult to achieve. Photonic glasses, comprising randomly arranged dielectric spheres, offer a promising solution toward such structural colors. However, their intrinsic disorder and particle size polydispersity typically lead to poor color saturation. Here, we identify two strategies employed by certain damselflies to generate unexpectedly vivid, tunable angle-independent colors from a photonic glass. First, doping of transparent pteridine nanospheres with yellow pigments strengthens blue–green reflectance resonances by simultaneously absorbing off-resonant wavelengths and enhancing the refractive-index near the reflectance band. Second, the refractive index of the nanospheres is modulated, via changes in crystallinity, to be almost exactly inversely correlated with nanosphere size. Thus, variations in nanosphere size, that ordinarily broaden reflectance resonances, resulting in poor color saturation, are compensated for by a correlated change in their refractive index. This ensures that even in a polydisperse ensemble, a consistent Mie scattering size parameter is maintained, strengthening short-range correlations and Mie scattering resonances. Finally, we show how damselflies tune these structural colors during maturation by precisely modulating the average size of the nanospheres, which arises naturally during the development of the pigment cells due to the densification and crystallization of the nanospheres. These findings reveal design strategies for overcoming limitations in the saturation of disordered photonic systems.
Highly Excited Electronic States of the Dicarbon Molecule: From Spectroscopy to Dynamics
ABSTRACT The dicarbon molecule (C 2 ) serves not only as a benchmark for studying chemical bonding, but also as an elementary building block in the bottom‐up synthesis of carbon materials, and a key species in astrochemistry. The spectroscopic and dynamic studies of C 2 have lasted for longer than two centuries, which provide invaluable insights into its complex electronic structure manifested as dense manifolds of low‐lying electronic states, quasi‐degenerate frontier orbitals, and significant multi‐configurational characters. From a materials perspective, spectroscopic and dynamical insights into the excited states of C 2 are pivotal for controlling the non‐equilibrium carbon chemistry in chemical vapor deposition (CVD) processes, where C 2 acts as a primary building block. Here, we present a comprehensive review of recent progress on the spectroscopic and dynamic study of C 2 , focusing on its highly excited states near or above the lowest dissociation threshold. These advances not only led to the identification of several new highly excited states but also provided important information on the decay dynamics in excited states, including state‐specific lifetimes and predissociation dynamics. Despite these advances, our understanding of the predissociation dynamics of C 2 remains limited; thus, several future prospects are proposed, and implications for the precise controlled synthesis of carbon materials are also mentioned.
Animals have expanded the evolutionary legacy of unicellular ancestors in blood cells
Blood cells are common and unique to animals, enabling them to address critical challenges of defense and transport. Thus, their evolution represents a defining innovation in metazoan multicellular life. However, their evolutionary trajectory about how blood cells emerged and diversified throughout animal history remains unclear. Here, we present a combination of bioinformatics and functional data that demonstrate that the metazoan blood cell program most likely originated through the repurposing of an ancestral premetazoan toolkit governed by Fos . This primordial program established the macrophage-like initial blood cells at the metazoan root. Then, the first lineage bifurcation at the origin of Bilateria drove the emergence of a specialized mast/killer lineage, characterized by acquisition of granular proteases for antiparasitic defense. Subsequent deuterostome/vertebrate innovations branched T/NK and erythrocyte/thrombocyte lineages from mast cells while B cells derived from macrophages. Our data also show that a prototypic thymus formed at the gill edges of a chordate ancestor. In line with the evolutionary history, the modern hematopoietic pathway shows a vestige of the phylogeny; differentiation potentials of phylogenetically old cell lineages expressing Fos such as macrophages and mast cells are widely retained, and ancient HSCs with limited lineage potentials have been inherited as origo-lineage progenitors. Our framework provides the history of blood cells showing an adaptive innovation built upon ancient unicellular foundations.
Chemical modulation of chloroplast de- and redifferentiation reveals a role for the SAL1–PAP retrograde pathway in facilitating plastid transitions
Plastids are dynamic organelles that remodel their composition, ultrastructure, and function according to developmental and environmental demands. The synthetic molecule X57 induces the conversion of leaf chloroplasts into tocopherol-rich plastids lacking thylakoids and containing proliferating plastoglobules. Removal of X57 triggers chloroplast redifferentiation, enabling precise spatial–temporal dissection of these transitions. X57 directly binds and inhibits the phosphatase SAL1, causing accumulation of its substrate 3′-phosphoadenosine 5′-phosphate (PAP), a retrograde signal that modulates nuclear gene expression. SAL1 inhibition activates a cascade that depletes cytokinins and down-regulates GOLDEN2-LIKE1 (GLK1) and other transcription factors involved in chloroplast biogenesis. SAL1-defective mutants fail to undergo this signaling pathway. The SAL1–PAP–mediated weakening of chloroplast identity preconditions plastids for their eventual conversion into storage-type organelles upon X57-promoted SAL1-independent accumulation of tocopherols. After X57 withdrawal, photosynthetic gene expression and chloroplast functions are restored. This framework identifies key molecular mechanisms underlying chloroplast plasticity, a central process in biology.
Langmuir-Hinshelwood pathway enables 1000-h stable nitrate-to-ammonia electroreduction at 1 A cm−2
Structural and functional characterisation of the Crimean-Congo haemorrhagic fever virus RNA dependent RNA polymerase
Abstract Crimean-Congo Haemorrhagic Fever Virus (CCHFV) is found across Africa, Asia, and the Middle East where it can cause Haemorrhagic outbreaks with high case fatality rates. Central to the viral life cycle is the viral L-protein, a crucial and multifunctional protein which both transcribes and replicates the viral genome. Here, we present the cryoEM structures of an RNA free and a 5′ promoter bound complex, describing the core catalytic RNA-dependent RNA polymerase (RdRp). We observe an RdRp that is substantially larger than related L-proteins and contains domain insertions unique to the nairovirus family. The 5′ RNA promoter is found in a tight RNA hairpin stabilised by a single base pair, with 5′ binding triggering the closure of protein over the RNA. Functional analysis of the endonuclease and RdRp activities reveals an enzyme which is capable of both activities and demonstrate RdRp inhibition by known antiviral nucleosides. These data advance our understanding of the molecular mechanisms behind genome replication and transcription, that will help inform future antiviral development.
Uniform nanoporous zirconia composite membrane enabling high-performance alkaline water electrolysis
Cell-to-cell variability and gain of methylation at polycomb CpG islands as a hallmark of aging
Fermi-level depinning achieved by high-work-function Au1-xSex alloy contacts for high-performance p-type WSe2 transistors
LRP4 is an entry receptor for multiple encephalitic alphaviruses
Sulfur-engineered rhenium single-atoms on borides for tunable syngas and lactic acid co-production
Constructing high-density active sites on hollow covalent organic polymers for efficient oxygen electrocatalysis
Abstract Creating efficient catalytic sites on covalent organic polymers (COPs) is a promising approach for green energy conversion and industrial catalysis. Although the post-synthetic modification of COPs has made progress in constructing single-atom sites and metal nanoparticles, this method remains limited in terms of the types, quantities, and overall performance of the constructing sites. To address these limitations, we develop a template-source construction strategy for catalytic site establishment. This strategy successfully yields hollow COPs with a high content of Co-O active species (H-COP-Co), demonstrating high activity as oxygen electrocatalysts. Comparing to traditional post-synthetically modified COPs with single Co sites (S-COP-Co), H-COP-Co demonstrates an increase in active metal content, from 2.96% to 56.86%, with enhanced catalytic activity for oxygen evolution reaction (OER). Unlike single Co sites that operate via the adsorbate evolution mechanism (AEM), comprehensive spectroscopic characterization and theoretical calculations reveal that the initial and reconstructed Co oxide nanoparticles in COPs operate via the oxide path mechanism, serving as the origin of the superior OER performance. These findings provide valuable insights into the design of multifunctional composite COP materials, underscoring the importance of intrinsically structural designing and modulating reaction mechanisms to enhance energy conversion efficiency.