Explore the vast range of titles available.

The root microbiota is critical for agricultural yield, with growth-promoting bacteria able to solubilise phosphate, produce plant growth hormones, antagonise pathogens and fix N 2 . Plants control the microorganisms in their immediate environment and this is at least in part through direct selection, the immune system, and interactions with other microorganisms. Considering the importance of the root microbiota for crop yields it is attractive to artificially regulate this environment to optimise agricultural productivity. Towards this aim we express a synthetic pathway for the production of the rhizopine scyllo -inosamine in plants. We demonstrate the production of this bacterial derived signal in both Medicago truncatula and barley and show its perception by rhizosphere bacteria, containing bioluminescent and fluorescent biosensors. This study lays the groundwork for synthetic signalling networks between plants and bacteria, allowing the targeted regulation of bacterial gene expression in the rhizosphere for delivery of useful functions to plants. The root microbiota is critical for promoting crop yield. Here, the authors create a synthetic pathway for the production of the rhizopine scyllo -inosamine in Medicago truncatula and barley, and show its perception by rhizosphere bacteria for targeted regulation of bacterial gene expression.

Reactive oxygen species (ROS) are a diverse group of molecules that serve as both essential signalling mediators and potential drivers of oxidative stress. In tumours, ROS influence critical processes such as proliferation, angiogenesis, metabolic adaptation and therapy resistance. These processes are further modulated by reduced oxygen availability (hypoxia), a defining feature of many solid tumours that can alter redox balance and cellular signalling. The interplay between ROS and hypoxia is highly dynamic, with both factors shaping tumour behaviour in complex and often unpredictable ways. Accurately measuring ROS and tumour oxygenation remains a significant challenge due to their transient nature and variability in levels across different tumour types. In this guide, we provide a comprehensive update on the dynamic interaction between ROS and hypoxia in tumours, evaluate current strategies for ROS detection and discuss emerging therapeutic approaches that target redox vulnerabilities in cancer. Understanding the intricate relationship between ROS and hypoxia is crucial for refining therapeutic strategies and improving patient outcomes. Hypoxia reshapes tumour redox landscapes by altering compartmental ROS production (mitochondria, NOX, ER, peroxisomes). Accurate interpretation requires oxygen‐contextualised measurement (live biosensors, chemical probes, EPR, LC–MS) and awareness of artefacts (reoxygenation, probe specificity). Therapeutic strategies either exploit elevated ROS to induce cell death or target antioxidant adaptations, with efficacy critically dependent on oxygenation and temporal dynamics. Created in BioRender. Hammond, E. (2025). https://BioRender.com/w3i8lv9.

Many solid tumors contain an aggressive hypoxic region that is difficult to treat. This protocol describes how to prepare bioreductive prodrugs that are biologically inactive until they are converted to an active drug by enzymatic reduction in hypoxia. Regions of insufficient oxygen supply—hypoxia—occur in diverse contexts across biology in both healthy and diseased organisms. The difference in the chemical environment between a hypoxic biological system and one with normal oxygen levels provides an opportunity for targeting compound delivery to hypoxic regions by using bioreductive prodrugs. Here we detail a protocol for the efficient synthesis of (1-methyl-2-nitro-1 H -imidazol-5-yl)methanol, which is a key intermediate that can be converted into a range of 1-methyl-2-nitro-1 H -imidazole–based precursors of bioreductive prodrugs. We outline methods for attaching the bioreductive group to a range of functionalities, and we discuss the strategy for positioning of the group on the biologically active parent compound. We have used two parent checkpoint kinase 1 (Chk1) inhibitors to exemplify the protocol. The PROCEDURE also describes a suite of reduction assays, of increasing biological relevance, to validate the bioreductive prodrug. These assays are applied to an exemplar compound, CH-01, which is a bioreductive Chk1 inhibitor. This protocol has broad applications to the development of hypoxia-targeted compounds.

Targeting the Pseudomonas aeruginosa virulence factor LasB is an innovative strategy to treat infections caused by this Gram-negative bacterium while minimizing resistance developing.

A versatile and Lipinski‐compliant DNA‐encoded library (DEL), comprising 366 600 glutamic acid derivatives coupled to oligonucleotides serving as amplifiable identification barcodes is designed, constructed, and characterized. The GB‐DEL library, constructed in single‐stranded DNA format, allows de novo identification of specific binders against several pharmaceutically relevant proteins. Moreover, hybridization of the single‐stranded DEL with a set of known protein ligands of low to medium affinity coupled to a complementary DNA strand results in self‐assembled selectable chemical structures, leading to the identification of affinity‐matured compounds. A single‐stranded DNA‐encoded chemical library (DEL) of 366 600 compounds, based on a stereoisomeric scaffold and on a single‐stranded DNA format, allows the isolation of ligands against multiple protein targets. The library can also be hybridized to a complementary DNA strand equipped with a protein binder, in order to generate affinity‐matured ligands.

Gram negative pathogens are protected against toxic electrophilic compounds by glutathione-gated potassium efflux systems (Kef) that modulate cytoplasmic pH. We have elucidated the mechanism of gating through structural and functional analysis of Escherichia coli KefC. The revealed mechanism can explain how subtle chemical differences in glutathione derivatives can produce opposite effects on channel function. Kef channels are regulated by potassium transport and NAD-binding (KTN) domains that sense both reduced glutathione, which inhibits Kef activity, and glutathione adducts that form during electrophile detoxification and activate Kef. We find that reduced glutathione stabilizes an interdomain association between two KTN folds, whereas large adducts sterically disrupt this interaction. F441 is identified as the pivotal residue discriminating between reduced glutathione and its conjugates. We demonstrate a major structural change on the binding of an activating ligand to a KTN-domain protein. Analysis of the regulatory interactions suggests strategies to disrupt pathogen potassium and pH homeostasis.

The opportunistic pathogen Pseudomonas aeruginosa produces colorful redox-active metabolites called phenazines, which underpin biofilm development, virulence, and clinical outcomes. Although phenazines exist in many forms, the best studied is pyocyanin. Here, we describe pyocyanin demethylase (PodA), a hitherto uncharacterized protein that oxidizes the pyocyanin methyl group to formaldehyde and reduces the pyrazine ring via an unusual tautomerizing demethylation reaction. Treatment with PodA disrupts P. aeruginosa biofilm formation similarly to DNase, suggesting interference with the pyocyanin-dependent release of extracellular DNA into the matrix. PodA-dependent pyocyanin demethylation also restricts established biofilm aggregate populations experiencing anoxic conditions. Together, these results show that modulating extracellular redox-active metabolites can influence the fitness of a biofilm-forming microorganism.

The encoding of chemical compounds with amplifiable DNA tags facilitates the discovery of small-molecule ligands for proteins. To investigate the impact of stereo- and regiochemistry on ligand discovery, we synthesized a DNA-encoded library of 670,752 derivatives based on 2-azido-3-iodophenylpropionic acids. The library was selected against multiple proteins and yielded specific ligands. The selection fingerprints obtained for a set of protein targets of pharmaceutical relevance clearly showed the preferential enrichment of ortho-, meta- or para-regioisomers, which was experimentally verified by affinity measurements in the absence of DNA. The discovered ligands included novel selective enzyme inhibitors and binders to tumour-associated antigens, which enabled conditional chimeric antigen receptor T-cell activation and tumour targeting.A DNA-encoded chemical library based on regio- and stereoisomers of phenylalanine has been synthesized and used for affinity-based selections against multiple target proteins. This approach led to the isolation and validation of potent ligands capable of CAR T-cell activation and tumour targeting.

The 3,5-dimethylisoxazole motif has become a useful and popular acetyl-lysine mimic employed in isoxazole-containing bromodomain and extra-terminal (BET) inhibitors but may introduce the potential for bioactivations into toxic reactive metabolites. As a test, we coupled deep neural models for quinone formation, metabolite structures, and biomolecule reactivity to predict bioactivation pathways for 32 BET inhibitors and validate the bioactivation of select inhibitors experimentally. Based on model predictions, inhibitors were more likely to undergo bioactivation than reported non-bioactivated molecules containing isoxazoles. The model outputs varied with substituents indicating the ability to scale their impact on bioactivation. We selected OXFBD02, OXFBD04, and I-BET151 for more in-depth analysis. OXFBD’s bioactivations were evenly split between traditional quinones and novel extended quinone-methides involving the isoxazole yet strongly favored the latter quinones. Subsequent experimental studies confirmed the formation of both types of quinones for OXFBD molecules, yet traditional quinones were the dominant reactive metabolites. Modeled I-BET151 bioactivations led to extended quinone-methides, which were not verified experimentally. The differences in observed and predicted bioactivations reflected the need to improve overall bioactivation scaling. Nevertheless, our coupled modeling approach predicted BET inhibitor bioactivations including novel extended quinone methides, and we experimentally verified those pathways highlighting potential concerns for toxicity in the development of these new drug leads.