Vitamin D receptor regulates methyltransferase like 14 to mitigate colitis-associated colorectal cancer.

Colitis-associated colorectal cancer (CAC), a serious complication of ulcerative colitis (UC), is associated with a poor prognosis. The vitamin D receptor (VDR) is recognized for its protective role in UC and CAC through the maintenance of intestinal barrier integrity and the regulation of inflammation. This study demonstrates a significant reduction in mA-related genes, particularly methyltransferase like 14 (METTL14), in UC and CAC patients and identifies an association between METTL14 and VDR.

Gut microbiome metabolites, molecular mimicry, and species-level variation drive long-term efficacy and adverse event outcomes in lung cancer survivors.

Background: The influence of the gut microbiota on long-term immune checkpoint inhibitor (ICI) efficacy and immune-related adverse events (irAEs) is poorly understood, as are the underlying mechanisms.

Methods: We performed gut metagenome and metabolome sequencing of gut microbiotas from patients with lung cancer initially treated with anti-PD-1/PD-L1 therapy and explored the underlying mechanisms mediating long-term (median follow-up 1167 days) ICI responses and immune-related adverse events (irAEs). Results were validated in external, publicly-available datasets (Routy, Lee, and McCulloch cohorts).

Boosting Chemiexcitation of Phenoxy-1,2-dioxetanes through 7-Norbornyl and Homocubanyl Spirofusion.

The chemiluminescent light-emission pathway of phenoxy-1,2-dioxetane luminophores is increasingly attracting the scientific community's attention. Dioxetane probes that undergo rapid, flash-type chemiexcitation demonstrate higher detection sensitivity than those with a slower, glow-type chemiexcitation rate. This is primarily because the rapid flash-type produces a greater number of photons within a given time.

Chemiexcitation Acceleration of 1,2-Dioxetanes by Spiro-Fused Six-Member Rings with Electron-Withdrawing Motifs.

The chemiluminescent light-emission pathway of phenoxy-1,2-dioxetane luminophores attracts growing interest within the scientific community. Dioxetane probes undergoing rapid flash-type chemiexcitation exhibit higher detection sensitivity than those with a slow glow-type chemiexcitation rate. We discovered that dioxetanes fused to non-strained six-member rings, with hetero atoms or inductive electron-withdrawing groups, present both accelerated chemiexcitation rates and elevated chemical stability compared to dioxetanes fused to four-member strained rings.

Photochemical Skeletal Editing of Pyridines to Bicyclic Pyrazolines and Pyrazoles.

We present an efficient one-pot photochemical skeletal editing protocol for the transformation of pyridines into diverse bicyclic pyrazolines and pyrazoles under mild conditions. The method requires no metals, photocatalysts, or additives and allows for the selective removal of specific carbon atoms from pyridines, allowing for unprecedented versatility. Our approach offers a convenient and efficient means for the late-stage modification of complex drug molecules by replacing the core pyridine skeleton.

Why •CFH is nucleophilic but •CF is electrophilic in reactions with heterocycles.

Radical substitution is a useful method to functionalize heterocycles, as in the venerable Minisci reaction. Empirically observed regiochemistries indicate that the CFH radical has a nucleophilic character similar to alkyl radicals, but the CF radical is electrophilic. While the difference between •CH and •CF is well understood, the reason that one and two Fs make little difference but the third has a large effect is puzzling.

Evaluation of Retro-Aldol vs Retro-Carbonyl-Ene Mechanistic Pathways in a Complexity-Generating C-C Bond Fragmentation.

We report an experimental and computational investigation of the likely mechanism of a cascade reaction. The reaction involves an intramolecular Diels-Alder reaction, followed by a C-C bond cleavage, to afford a complex bridged bicyclic product. As multiple reaction pathways could be envisioned for the latter step, the mechanism of the C-C bond cleavage step was investigated.

Characterizing Hydroxyl Radical Formation from the Light-Driven Fe(II)-Peracetic Acid Reaction, a Key Process for Aerosol-Cloud Chemistry.

The reaction of peracetic acid (PAA) and Fe(II) has recently gained attention due to its utility in wastewater treatment and its role in cloud chemistry. Aerosol-cloud interactions, partly mediated by aqueous hydroxyl radical (OH) chemistry, represent one of the largest uncertainties in the climate system. Ambiguities remain regarding the sources of OH in the cloud droplets.

Spirostrain-Accelerated Chemiexcitation of Dioxetanes Yields Unprecedented Detection Sensitivity in Chemiluminescence Bioassays.

Chemiluminescence is a fascinating phenomenon that involves the generation of light through chemical reactions. The light emission from adamantyl-phenoxy-1,2-dioxetanes can glow from minutes to hours depending on the specific substituent present on the dioxetane molecule. In order to improve the light emission properties produced by these chemiluminescent luminophores, it is necessary to induce the chemiexcitation rate to a flash mode, wherein the bulk of light is emitted instantly rather than slowly over time.

Iron Heme Enzyme-Catalyzed Cyclopropanations with Diazirines as Carbene Precursors: Computational Explorations of Diazirine Activation and Cyclopropanation Mechanism.

The mechanism of cyclopropanations with diazirines as air-stable and user-friendly alternatives to commonly employed diazo compounds within iron heme enzyme-catalyzed carbene transfer reactions has been studied by means of density functional theory (DFT) calculations of model systems, quantum mechanics/molecular mechanics (QM/MM) calculations, and molecular dynamics (MD) simulations of the iron carbene and the cyclopropanation transition state in the enzyme active site. The reaction is initiated by a direct diazirine-diazo isomerization occurring in the active site of the enzyme. In contrast, an isomerization mechanism proceeding via the formation of a free carbene intermediate of a direct, one-step isomerization process was observed for model systems.

A 21st Century View of Allowed and Forbidden Electrocyclic Reactions.

In 1965, Woodward and Hoffmann proposed a theory to predict the stereochemistry of electrocyclic reactions, which, after expansion and generalization, became known as the Woodward-Hoffmann Rules. Subsequently, Longuet-Higgins and Abrahamson used correlation diagrams to propose that the stereoselectivity of electrocyclizations could be explained by the correlation of reactant and product orbitals with the same symmetry. Immediately thereafter, Hoffmann and Woodward applied correlation diagrams to explain the mechanism of cycloadditions.

A Synergistic Antibacterial Study of Copper-Doped Polydopamine on TiCT Nanosheets with Enhanced Photothermal and Fenton-like Activities.

In response to the trend of drug-resistant and super bacteria, the existing single antibacterial methods are not sufficient to kill bacteria, and the development of multifunctional antibacterial nanomaterials is urgent. Our study aims to construct copper-doped polydopamine-coated TiCT (CuPDA@TiCT) with an enhanced photothermal property and Fenton-like activity. The nanocomposite hydrogel consisting of CuPDA@TiCT and alginate can improve the antioxidant activity of two-dimensional MXene nanosheets by coating them with a thin layer of PDA nanofilm.

Genome Mining from Agriculturally Relevant Fungi Led to a d-Glucose Esterified Polyketide with a Terpene-like Core Structure.

Comparison of biosynthetic gene clusters (BGCs) found in devastating plant pathogens and biocontrol fungi revealed an uncharacterized and conserved polyketide BGC. Genome mining identified the associated metabolite to be treconorin, which has a terpene-like, fused 5,7-bicyclic core that is proposed to derive from a (4 + 3) cycloaddition. The core is esterified with d-glucose, which derives from the glycosidic cleavage of a trehalose ester precursor.

Computational Exploration of the Thermal Rearrangement of Basketene: One Forbidden versus Two Allowed Pericyclic Reactions.

The thermal rearrangement of basketene to Nenitzescu's hydrocarbon has been explored using density functional theory (M06-2X and ωB97X-D) and DLPNO-CCSD(T) quantum mechanics. Both the sequential thermally allowed retro Diels-Alder followed by Cope rearrangement and the thermally forbidden retro-[2 + 2] cycloaddition were studied. The controlling role of orbital symmetry rather than reaction thermodynamics is demonstrated.

Enzymatic Benzofuranoindoline Formation in the Biosynthesis of the Strained Bridgehead Bicyclic Dipeptide (+)-Azonazine A.

We uncovered and reconstituted a concise biosynthetic pathway of the strained dipeptide (+)-azonazine A from marine-derived Aspergillus insulicola. Formation of the hexacyclic benzofuranoindoline ring system from cyclo-(l-Trp-N-methyl-l-Tyr) is catalyzed by a P450 enzyme through an oxidative cyclization. Supplementing the producing strain with various indole-substituted tryptophan derivatives resulted in the generation of a series of azonazine A analogs.

Experimental and Theoretical Exploration of the Kinetics and Thermodynamics of the Nucleophile-Induced Fragmentation of Ylidenenorbornadiene Carboxylates.

Ylidenenorbornadienes (YNDs), prepared by [4 + 2] cycloadditions between fulvenes and acetylene carboxylates, react with thiol nucleophiles to yield mixtures of four to eight diastereomers depending on the symmetry of the YND substrate. The mixtures of diastereomers fragment via a retro-[4 + 2] cycloaddition with a large variation in rate, with half-lives ranging from 16 to 11,000 min at 80 °C. The diastereomer-enriched samples of propane thiol adducts [YND-propanethiol (PTs)] were isolated and identified by nuclear Overhauser effect spectroscopy (NOESY) correlations.

New score models for assessing disease activity in Crohn's disease based on bowel ultrasound and biomarkers: Ideal surrogates for endoscopy or imaging.

Disease activity evaluation is important in Crohn's disease (CD). We aimed to establish new disease activity indices for CD based on noninvasive parameters. The data of 110 patients with CD were retrospectively analyzed.

Tandem intermolecular [4 + 2] cycloadditions are catalysed by glycosylated enzymes for natural product biosynthesis.

Tandem Diels-Alder reactions are frequently used in the construction of polycyclic ring systems in complex organic compounds. Unlike the many Diels-Alderases (DAases) that catalyse a single cycloaddition, enzymes for multiple Diels-Alder reactions are rare. Here we demonstrate that two calcium-ion-dependent glycosylated enzymes, EupfF and PycR1, independently catalyse sequential, intermolecular Diels-Alder reactions in the biosynthesis of bistropolone-sesquiterpenes.

Vitamin D Status Is Associated With Immune Checkpoint Inhibitor Efficacy and Immune-related Adverse Event Severity in Lung Cancer Patients: A Prospective Cohort Study.

Vitamin D (VitD) is potentially immunomodulatory, so here we aimed to explore the relationships between serum VitD levels, immune checkpoint inhibitor (ICI) efficacy, and immune-related adverse events (irAEs). Serum 25-hydroxyvitamin D [25(OH)D] levels were quantified before and after ICI treatment in prospectively enrolled patients with advanced lung cancers. Of 77 enrolled patients, 29 developed 42 irAEs.

Dynamic gut microbiota changes in patients with advanced malignancies experiencing secondary resistance to immune checkpoint inhibitors and immune-related adverse events.

Background: Immune checkpoint inhibitors (ICIs) have been a breakthrough in cancer immunotherapy, but secondary resistance (SR) and immune-related adverse events (irAEs) are significant clinical dilemmas. Although the gut microbiota is associated with ICI efficacy and irAEs, the knowledge of longitudinal gut microbiota dynamics during SR and irAE development is still quite limited.

Methods: This was a prospective observational cohort study of cancer patients initially receiving anti-programmed cell death-1 (PD-1) treatment between May 2020 and October 2022.

Improving the Performance of a Triboelectric Nanogenerator by Using an Asymmetric TiO/PDMS Composite Layer.

To improve the output power of the polydimethylsiloxane (PDMS)-based triboelectric nanogenerators (TENGs), we fabricated an asymmetric TiO/PDMS composite film in which a pure PDMS thin film was deposited as a capping layer on a TiO nanoparticles (NPs)-embedded PDMS composite film. Although in the absence of the capping layer, the output power decreased when the content of TiO NPs exceeded a certain value, the asymmetric TiO/PDMS composite films showed that the output power increased with increasing content. The maximum output power density was approximately 0.

Gut microbiota composition in patients with advanced malignancies experiencing immune-related adverse events.

Introduction: The gut microbiota is implicated in the occurrence and severity of immune-related adverse events (irAEs), but the role it plays as well as its causal relationship with irAEs has yet to be established.

Methods: From May 2020 to August 2021, 93 fecal samples were prospectively collected from 37 patients with advanced thoracic cancers treated with anti-PD-1 therapy, and 61 samples were collected from 33 patients with various cancers developing different irAEs. 16S rDNA amplicon sequencing was performed.

Advancing the precision management of inflammatory bowel disease in the era of omics approaches and new technology.

There is great heterogeneity among inflammatory bowel disease (IBD) patients in terms of pathogenesis, clinical manifestation, response to treatment, and prognosis, which requires the individualized and precision management of patients. Many studies have focused on prediction biomarkers and models for assessing IBD disease type, activity, severity, and prognosis. During the era of biologics, how to predict the response and side effects of patients to different treatments and how to quickly recognize the loss of response have also become important topics.