There is a significant drive to identify alternative materials that exhibit room temperature phosphorescence for technologies including bio-imaging, photodynamic therapy and organic light-emitting ...diodes. Ideally, these materials should be non-toxic and cheap, and it will be possible to control their photoluminescent properties. This was achieved here by embedding carbon nanodots within crystalline particles of alkaline earth carbonates, sulphates and oxalates. The resultant nanocomposites are luminescent and exhibit a bright, sub-second lifetime afterglow. Importantly, the excited state lifetimes, and steady-state and afterglow colours can all be systematically controlled by varying the cations and anions in the host inorganic phase, due to the influence of the cation size and material density on emissive and non-emissive electronic transitions. This simple strategy provides a flexible route for generating materials with specific, phosphorescent properties and is an exciting alternative to approaches relying on the synthesis of custom-made luminescent organic molecules.
There is an urgent need to create novel models using human disease-relevant cells to study severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) biology and to facilitate drug screening. Here, ...as SARS-CoV-2 primarily infects the respiratory tract, we developed a lung organoid model using human pluripotent stem cells (hPSC-LOs). The hPSC-LOs (particularly alveolar type-II-like cells) are permissive to SARS-CoV-2 infection, and showed robust induction of chemokines following SARS-CoV-2 infection, similar to what is seen in patients with COVID-19. Nearly 25% of these patients also have gastrointestinal manifestations, which are associated with worse COVID-19 outcomes
. We therefore also generated complementary hPSC-derived colonic organoids (hPSC-COs) to explore the response of colonic cells to SARS-CoV-2 infection. We found that multiple colonic cell types, especially enterocytes, express ACE2 and are permissive to SARS-CoV-2 infection. Using hPSC-LOs, we performed a high-throughput screen of drugs approved by the FDA (US Food and Drug Administration) and identified entry inhibitors of SARS-CoV-2, including imatinib, mycophenolic acid and quinacrine dihydrochloride. Treatment at physiologically relevant levels of these drugs significantly inhibited SARS-CoV-2 infection of both hPSC-LOs and hPSC-COs. Together, these data demonstrate that hPSC-LOs and hPSC-COs infected by SARS-CoV-2 can serve as disease models to study SARS-CoV-2 infection and provide a valuable resource for drug screening to identify candidate COVID-19 therapeutics.
Iron sulfur (Fe-S) phases have been implicated in the emergence of life on early Earth due to their catalytic role in the synthesis of prebiotic molecules. Similarly, Fe-S phases are currently of ...high interest in the development of green catalysts and energy storage. Here we report the synthesis and structure of a nanoparticulate phase (FeS
) that is a necessary solid-phase precursor to the conventionally assumed initial precipitate in the iron sulfide system, mackinawite. The structure of FeS
contains tetrahedral iron, which is compensated by monosulfide and polysulfide sulfur species. These together dramatically affect the stability and enhance the reactivity of FeS
.
Synthesis of well-defined neoglycopolymer−protein biohybrid materials and a preliminary study focused on their ability of binding mammalian lectins and inducing immunological function is reported. ...Crucial intermediates for their preparation are well-defined maleimide-terminated neoglycopolymers (M n = 8−30 kDa; M w/M n = 1.20−1.28) presenting multiple copies of mannose epitope units, obtained by combination of transition-metal-mediated living radical polymerization (TMM LRP) and Huisgen 2+3 cycloaddition. Bovine serum albumin (BSA) was employed as single thiol-containing model protein, and the resulting bioconjugates were purified following two independent protocols and characterized by circular dichroism (CD) spectroscopy, SDS PAGE, and SEC HPLC. The versatility of the synthetic strategy presented in this work was demonstrated by preparing a small library of conjugating glycopolymers that only differ from each other for their relative epitope density were prepared by coclicking of appropriate mixtures of mannopyranoside and galactopyranoside azides to the same polyalkyne scaffold intermediate. Surface plasmon resonance binding studies carried out using recombinant rat mannose-binding lectin (MBL) showed clear and dose-dependent MBL binding to glycopolymer-conjugated BSA. In addition, enzyme-linked immunosorbent assay (ELISA) revealed that the neoglycopolymer−protein materials described in this work possess significantly enhanced capacity to activate complement via the lectin pathway when compared with native unmodified BSA.
Despite lacking a DNA intermediate, orthomyxoviruses complete their replication cycle in the nucleus and generate multiple transcripts by usurping the host splicing machinery. This biology results in ...dynamic changes of relative viral transcripts over time and dictates the replicative phase of the infection. Here, we demonstrate that the family of archaeal L7Ae proteins uniquely inhibit the splicing biology of influenza A virus, influenza B virus, and Salmon isavirus, revealing a common strategy utilized by
members to achieve this dynamic. L7Ae-mediated inhibition of virus biology was lost with the generation of a splicing-independent strain of influenza A virus and attempts to select for an escape mutant resulted in variants that conformed to host splicing biology at significant cost to their overall fitness. As L7Ae recognizes conventional kink turns in various RNAs, these data implicate the formation of a similar structure as a shared strategy adopted by this virus family to coordinate their replication cycle.
Here, we demonstrate that a family of proteins from archaea specifically inhibit this splicing biology of all tested members of the
family. We show that this inhibition extends to influenza A virus, influenza B virus, and isavirus genera, while having no significant impact on the mammalian transcriptome or proteome. Attempts to generate an escape mutant against L7Ae-mediated inhibition resulted in mutations surrounding the viral splice sites and a significant loss of viral fitness. Together, these findings reveal a unique biology shared among diverse members of the
family that may serve as a means to generate future universal therapeutics.
The α-functionalisation of N -containing compounds is an area of broad interest in synthetic chemistry due to their presence in biologically active substances among others. Visible light-induced ...generation of nucleophilic α-aminoalkyl radicals as reactive intermediates that can be trapped by electron-deficient alkenes presents an attractive and mild approach to achieve said functionalisation. In this work, Fe( iii )(phtmeimb) 2 PF 6 (phtmeimb = phenyl(tris(3-methylimidazol-2-ylidene))borate), an N-heterocyclic carbene (NHC) complex based on Earth-abundant iron, was used as photoredox catalyst to efficiently drive the formation of α-aminoalkyl radicals from a range of different α-trimethylsilylamines and their subsequent addition to a number of electron-deficient alkenes under green light irradiation. Mechanistic investigations elucidated the different reaction steps of the complete photocatalytic cycle. In terms of yields and substrate scope, we show that Fe( iii )(phtmeimb) 2 PF 6 can compete with noble metal photoredox catalysts, for instance outcompeting archetypal Ru(bpy) 3 Cl 2 under comparable reaction conditions, illustrating that iron photocatalysts can efficiently facilitate photoredox reactions of synthetic value.
Micron-sized lipid-stabilised bubbles of heavy gas have been utilised as contrast agents for diagnostic ultrasound (US) imaging for many years. Typically bubbles between 1 and 8 μm in diameter are ...produced to enhance imaging in US by scattering sound waves more efficiently than surrounding tissue. A potential area of interest for Contrast Enhanced Ultrasound (CEUS) are bubbles with diameters <1 μm or 'nanobubbles.' As bubble diameter decreases, ultrasonic resonant frequency increases, which could lead to an improvement in resolution for high-frequency imaging applications when using nanobubbles. In addition, current US contrast agents are limited by their size to the vasculature in vivo. However, molecular-targeted nanobubbles could penetrate into the extra-vascular space of cancerous tissue providing contrast in regions inaccessible to traditional microbubbles. This paper reports a new microfluidic method for the generation of sub-micron sized lipid stabilised particles containing perfluorocarbon (PFC). The nanoparticles are produced in a unique atomisation-like flow regime at high production rates, in excess of 10(6) particles per s and at high concentration, typically >10(11) particles per mL. The average particle diameter appears to be around 100-200 nm. These particles, suspected of being a mix of liquid and gaseous C4F10 due to Laplace pressure, then phase convert into nanometer sized bubbles on the application of US. In vitro ultrasound characterisation from these nanoparticle populations showed strong backscattering compared to aqueous filled liposomes of a similar size. The nanoparticles were stable upon injection and gave excellent contrast enhancement when used for in vivo imaging, compared to microbubbles with an equivalent shell composition.
Microbubbles (MBs) have a multitude of applications including as contrast agents in ultrasound imaging and as therapeutic drug delivery vehicles, with further scope for combining their diagnostic and ...therapeutic properties (known as theranostics). MBs used clinically are commonly made by mechanical agitation or sonication methods, which offer little control over population size and dispersity. Furthermore, clinically used MBs are yet to be used therapeutically and further research is needed to develop these theranostic agents. In this paper, we present our MB production instrument "Horizon," which is a robust, portable, and user-friendly instrument, integrating the key components for producing MBs using microfluidic flow-focusing devices. In addition, we present the system design and specifications of Horizon and the optimized protocols that have so far been used to produce MBs with specific properties. These include MBs with tailored size and low dispersity (monodisperse); MBs with a diameter of ∼2 μm, which are more disperse but also produced in higher concentration; nanobubbles with diameters of 100-600 nm; and therapeutic MBs with drug payloads for targeted delivery. Multiplexed chips were able to improve production rates up to 16-fold while maintaining production stability. This work shows that Horizon is a versatile instrument with potential for mass production and use across many research facilities, which could begin to bridge the gap between therapeutic MB research and clinical use.
Michigan InfraRed Combiner-eXeter (MIRC-X) is a new highly sensitive six-telescope interferometric imager installed at the CHARA Array that provides an angular resolution equivalent of up to a 330 m ...diameter baseline telescope in J- and H-band wavelengths ( mas). We upgraded the original Michigan InfraRed Combiner (MIRC) instrument to improve sensitivity and wavelength coverage in two phases. First, a revolutionary sub-electron noise and fast-frame-rate C-RED ONE camera based on an SAPHIRA detector was installed. Second, a new-generation beam combiner was designed and commissioned to (i) maximize sensitivity, (ii) extend the wavelength coverage to J band, and (iii) enable polarization observations. A low-latency and fast-frame-rate control software enables high-efficiency observations and fringe tracking for the forthcoming instruments of the CHARA Array. Since mid-2017, MIRC-X has been offered to the community and has demonstrated best-case H-band sensitivity down to 8.2 correlated magnitude. MIRC-X uses single-mode fibers to coherently combine the light from six telescopes simultaneously with an image-plane combination scheme and delivers a visibility precision better than 1%, and closure phase precision better than 1°. MIRC-X aims at (i) imaging protoplanetary disks, (ii) detecting exoplanets with precise astrometry, and (iii) imaging stellar surfaces and starspots at an unprecedented angular resolution in the near-infrared. In this paper, we present the instrument design, installation, operation, and on-sky results, and demonstrate the imaging capability of MIRC-X on the binary system Peg. The purpose of this paper is to provide a solid reference for studies based on MIRC-X data and to inspire future instruments in optical interferometry.
Distinguishing independent primary tumors from intrapulmonary metastases in non-small-cell carcinoma remains a clinical dilemma with significant clinical implications. Using next-generation DNA ...sequencing, we developed a chromosomal rearrangement-based approach to differentiate multiple primary tumors from metastasis.
Tumor specimens from patients with known independent primary tumors and metastatic lesions were used for lineage test development, which was then applied to multifocal tumors. Laser capture microdissection was performed separately for each tumor. Genomic DNA was isolated using direct in situ whole-genome amplification methodology, and next-generation sequencing was performed using an Illumina mate-pair library protocol. Sequence reads were mapped to the human genome, and primers spanning the fusion junctions were used for validation polymerase chain reaction.
A total of 41 tumor samples were sequenced (33 adenocarcinomas ADs and eight squamous cell carcinomas SQCCs), with a range of three to 276 breakpoints per tumor identified. Lung tumors predicted to be independent primary tumors based on different histologic subtype did not share any genomic rearrangements. In patients with lung primary tumors and paired distant metastases, shared rearrangements were identified in all tumor pairs, emphasizing the patient specificity of identified breakpoints. Multifocal AD and SQCC samples were reviewed independently by two pulmonary pathologists. Concordance between histology and genomic data occurred in the majority of samples. Discrepant tumor samples were resolved by genome sequencing.
A diagnostic lineage test based on genomic rearrangements from mate-pair sequencing demonstrates promise for distinguishing independent primary from metastatic disease in lung cancer.
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