The RHIM of the Immune Adaptor Protein TRIF Forms Hybrid Amyloids with Other Necroptosis-Associated Proteins

TIR-domain-containing adapter-inducing interferon-β (TRIF) is an innate immune protein that serves as an adaptor for multiple cellular signalling outcomes in the context of infection. TRIF is activated via ligation of Toll-like receptors 3 and 4. One outcome of TRIF-directed signalling is the activation of the programmed cell death pathway necroptosis, which is governed by interactions between proteins that contain a RIP Homotypic Interaction Motif (RHIM). TRIF contains a RHIM sequence and can interact with receptor interacting protein kinases 1 (RIPK1) and 3 (RIPK3) to initiate necroptosis. Here, we demonstrate that the RHIM of TRIF is amyloidogenic and supports the formation of homomeric TRIF-containing fibrils. We show that the core tetrad sequence within the RHIM governs the supramolecular organisation of TRIF amyloid assemblies, although the stable amyloid core of TRIF amyloid fibrils comprises a much larger region than the conserved RHIM only. We provide evidence that RHIMs of TRIF, RIPK1 and RIPK3 interact directly to form heteromeric structures and that these TRIF-containing hetero-assemblies display altered and emergent properties that likely underlie necroptosis signalling in response to Toll-like receptor activation.     

A new route to triphenylpyridines utilizing ketoximes as building blocks via cascade reactions under iron‐organic framework catalysis

Iron‐based metal–organic framework VNU‐20 was utilized as a heterogeneous catalyst for cascade reactions between ketoximes and dibenzyl ether to produce 2,4,6‐triphenylpyridines. Additionally, benzyl alcohol and (dimethoxymethyl)benzene could be used as an alternative starting materials for the transformation. The oxidant exhibited a remarkable impact on the reactions, and di‐tert‐butylperoxide was the most appropriate candidate. The VNU‐20 displayed higher efficiency than many homogeneous and heterogeneous catalysts. The catalyst was reusable for the cascade reactions without a noticeable deterioration in catalytic activity. This transformation is new, and would offer alternative routes to triphenylpyridines utilizing ketoximes as building blocks.     

Molecular Sieving of Acetylene from Ethylene in a Rigid Ultra-microporous Metal Organic Framework.

Rigid molecular sieving materials are the ideal candidates for gas separation (e. g., C₂H₂/C₂H₄) due to their ultrahigh adsorption selectivity and the absence of gas co-adsorption. However, the absolute molecular sieving effect for C₂H₂/C₂H₄ separation has rarely been realized because of their similar physicochemical properties. Herein, we demonstrate the absolute molecular sieving of C₂H₂ from C₂H₄ by a rigid ultra-microporous metal-organic framework ( F−PYMO−Cu ) with 1D regular channels (pore size of ca. 3.4 Å). F−PYMO−Cu exhibited moderate acetylene uptake (35.5 cm³/cm³), but very low ethylene uptake (0.55 cm³/cm³) at 298 K and 1 bar, yielding the second highest C₂H₂/C₂H₄ uptake ratio of 63.6 up to now. One-step C₂H₄ production from a binary mixture of C₂H₂/C₂H₄ and a ternary mixture of C₂H₂/CO₂/C₂H₄ at 298 K was achieved and verified by dynamic breakthrough experiments. Coupled with excellent thermal and water stability, F−PYMO−Cu could be a promising candidate for industrial C₂ separation tasks.     

Propagation of Perturbations in a Boundary Layer under Strong Hypersonic Interaction

Doklady Physics - Nonstationary processes in a hypersonic boundary layer are studied. A phase shift by propagation of perturbations upstream was found caused by a finite upstream propagation...     

Synthesis of α,β- and β-Unsaturated Acids and Hydroxy Acids by Tandem Oxidation,Epoxidation, and Hydrolysis/Hydrogenation of Bioethanol Derivatives

We report a reaction platform for the synthesis of three different high-value specialty chemical building blocks starting from bio-ethanol, which might have an important impact in the implementation of biorefineries. First, oxidative dehydrogenation of ethanol to acetaldehyde generates an aldehyde-containing stream active for the production of C₄ aldehydes via base-catalyzed aldol-condensation. Then, the resulting C₄ adduct is selectively converted into crotonic acid via catalytic aerobic oxidation (62 % yield). Using a sequential epoxidation and hydrogenation of crotonic acid leads to 29 % yield of β-hydroxy acid (3-hydroxybutanoic acid). By controlling the pH of the reaction media, it is possible to hydrolyze the oxirane moiety leading to 21 % yield of α,β-dihydroxy acid (2,3-dihydroxybutanoic acid). Crotonic acid, 3-hydroxybutanoic acid, and 2,3-dihydroxybutanoic acid are archetypal specialty chemicals used in the synthesis of polyvinyl-co-unsaturated acids resins, pharmaceutics, and bio-degradable/ -compatible polymers, respectively.     

Altered mitochondrial structure and motion dynamics in living cells with energy metabolism defects revealed by real time microscope imaging.

Using the real time microscope (RTM), a system applying new developments in light microscopy, we documented the spatial and temporal dynamics of mitochondrial behavior in human cultured skin fibroblasts. Without the use of stains or probes, we resolved fibroblast mitochondria as dark slender filaments of approximately 0.2 m wide and up to 10 m long, as well as a few smaller ovoid forms. In the living cell, the three most common mitochondrial movements were: (1) small oscillatory movements; (2) larger movements including filament extension, retraction, and branching as well as combinations of these actions; and (3) whole transit movements of single mitochondrial filaments. Skin fibroblasts from patients with mitochondrial complex I deficiency and normal fibroblasts during incubation with rotenone, or antimycin A, contained higher proportions of mitochondria in the swollen filamentous forms, nodal filaments, and ovoid forms rather than the slender filamentous forms in normal cells. Interestingly, decreased motility was observed with the more ovoid mitochondrial forms compared to the filamentous forms. We conclude that mitochondrial morphology and dynamic motion are strongly associated with changes in mitochondrial energy metabolism. Images documenting our observations are presented both at single time points and as QuickTime videos.     

Noise reduction in sputtered W/GaAs Schottky junctions

The noise characteristics of sputtered W/GaAs Schottky diodes, annealed at temperatures up to 700°C, have been investigated. A useful figure of merit for such millimeter and submillimeter mixer diodes is the noise performance at an RF where accurate measurements are available. Noise temperatures measured at a typical mixer intermediate frequency of 4GHz under DC biased conditions have been reduced significantly by rapid thermal annealing. The best noise data have been obtained with an annealing time of 2 minutes at 600°C and are consistent with good mixer performance.     

Résurgence d’un thème de Huygens-Fresnel

Sans résumé Dédié à René Thom.