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Today, 12:14 AM
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Nutrition plays a fundamental role in shaping human health across the life course, influencing both host physiology and the composition and function of the gut microbiota. In turn, the gut microbiota modulates the effects of dietary intake, creating complex bidirectional interactions with profound implications for metabolic health. Although the concept of personalized nutrition offering tailored dietary advice based on observable traits, environmental factors, and genotype has gained prominence, growing evidence supports the promise of precision nutrition that also considers individual microbiome profiles. This approach is particularly relevant for addressing diet-related conditions such as obesity and type 2 diabetes, where interindividual variability in response to the same diet is well documented. Advances in high-throughput sequencing, metabolomics, and machine learning are driving predictive models that can forecast personalized dietary outcomes. However, methodological heterogeneity, lack of consistency, and limited representation of diverse populations in current studies present significant barriers. Ethical challenges, including data privacy and equitable access to personalized nutrition tools, also warrant urgent attention. To realize the full potential of microbiome-informed nutrition, greater harmonization of research methods, robust validation across large and diverse cohorts, and an interdisciplinary framework are essential.
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Today, 12:03 AM
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Bacterial growth and respiration are fundamental metabolic processes that affect how energy is used and impact carbon sequestration at the ecosystem scale. However, these traits are usually quantified independently, growth is quantified with endpoint biomass measurements while respiration is quantified by monitoring oxygen or carbon dioxide. Because the two physiological traits are collected at different temporal and volumetric scales (hours-to-days for growth versus minutes-to-hours for respiration), reconciling them is challenging and often introduces scale-mismatch bias, obscuring causal links between metabolism and environmental drivers. In this study, we develop a novel method for quantifying the rates of bacterial growth and respiration concurrently from a single dissolved oxygen time series. Our approach introduces a model that couples exponential biomass growth with biomass-specific respiration, enabling the simultaneous inference of both rates in real time. We applied our high throughput method to 15 bacterial strains isolated from natural environments. Our approach yielded growth estimates in close agreement with measurements based on popular methods using optical density or flow cytometry with no evidence of taxon-specific bias. We also tested our approach in quantifying the effects of temperature on respiration, growth and carbon use-efficiency in Pseudomonas sp. Our method yielded typical unimodal thermal response curves for growth and respiration where rates were highest at moderate temperatures, while carbon-use efficiency increased from cooler temperatures, peaked around the thermal optimum, and declined at high temperature. By quantifying respiration and growth simultaneously and in high throughput, our approach effectively enables measurement of microbial metabolic strategies and adaptations to stress. It offers a non-invasive and scalable tool for high throughput phenotyping and studies of environmental perturbations, enabling a new class of trait-based microbial ecology that links cellular physiology to broader ecosystem function.
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December 10, 11:27 PM
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Host specificity of a plant pathogen is defined by its effector complement. However, it remains unclear whether the full complement is required for pathogenicity. Pseudomonas syringae pv. actinidiae (Psa) is an emerging model pathogen of kiwifruit with over 30 functional effectors, providing a unique opportunity to understand how host-mediated selection shapes pathogen evolution. The majority of Psa’s effectors previously appeared nonessential in single knockout contexts. Why, then, does Psa maintain such a large repertoire? We sought to examine effector requirements, redundancies, and repertoire refinement across host genotypes through a mutated effector-leveraging evolution experiment (MELEE), serially passaging competitive populations of effector knockout strains. Competition suggests that all effectors are collectively required for successful virulence, demonstrated by the dominance of wild-type. Host-specific effector requirements identified may further explain the maintenance of this large effector repertoire, providing important insights into the dynamics of effector redundancy following incursions.
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December 10, 11:20 PM
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Transcription factors (TFs) affect gene expression by binding to their sites (TFBSs) in the genome. As regulation of transcription is essential for the optimization of metabolism, evolution of TFBSs is thought to be restricted by the TF binding preferences. This means that nucleotides important for binding (consensus nucleotides, CNs) experience the pressure of negative selection and, therefore, are highly conserved. However, for some regulated genes, the strongest possible repression or activation may not necessarily be optimal (i.e. provide the highest fitness). Here, we show that, along with CNs, nucleotides causing relatively weaker binding (nonconsensus nucleotides, NCNs) are sometimes preserved by negative selection. We then consider several possible reasons for the conservation of NCNs and demonstrate that NCNs depend epistatically on other loci of the same TFBS for a substantial fraction of TFBSs.
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December 10, 11:01 PM
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Nanopore direct RNA sequencing offers a versatile approach for detecting multiple types of RNA modifications at a single-base resolution. In this study, we systematically evaluate 86 computational tools for detecting six RNA modifications (m6A, Ψ, m5C, A-to-I editing, m7G and m1A) using direct RNA sequencing data from both RNA002 and RNA004 chemistries. We demonstrate that retraining tools with a combination of in vitro transcription and real biological samples notably enhances both accuracy and generalizability over their original implementations, especially for Ψ, m5C and A-to-I. Evaluations on real biological samples reveal that while m6A detection tools generally achieve high accuracy, non-m6A tools struggle with precision–recall balance, quantification accuracy and biological validity. Our findings highlight the importance of incorporating diverse training data and stress the need for tools capable of reliably distinguishing between modification types at single-base resolution. These insights provide a foundation for advancing RNA modification detection. This analysis benchmarked computational tools for RNA modification detection using nanopore direct RNA sequencing and showed that retraining with mixed in vitro transcription and real data improves performance.
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December 10, 10:45 PM
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Biofilms are critical for the environmental persistence, survival, and infectivity of Vibrio cholerae, the causative agent of cholera. Here, we find that GluP, a glutamate-specific TRAP-TAXI protein, is an uncharacterized matrix component that plays a critical role in biofilm architecture. Loss of GluP reduces biofilm corrugation, expands colony size, and disperses cells from microcolonies, arguing that this factor maintains biofilm structure and organization. While GluP does not affect the abundance or localization of known matrix proteins, its absence reduces Vibrio exopolysaccharide (VPS) production. We determined the crystal structure of GluP, which revealed that GluP binds glutamate, and its biofilm-related phenotypes depend on this binding capability. We further examined the role of GluP in V. cholerae growth under defined conditions where L-glutamate serves as a carbon source, nitrogen source, or both. GluP-deficient strains specifically showed reduced growth when glucose was the carbon source and glutamate the nitrogen source. This defect is dependent on glutamate binding by GluP and highlights its role in coordinating nutrient acquisition and biofilm formation. Importantly, both biofilm assembly and growth defects occurred independently of the predicted membrane component of the Glu TRAP-TAXI system, GluQM. These findings indicate that GluP plays a dual role in biofilm assembly and growth, providing insight into its functional importance in V. cholerae physiology.
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December 10, 10:18 PM
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Protein Data Bank in Europe (PDBe) is a founding member of the worldwide Protein Data Bank (wwPDB), delivering open access to experimentally determined macromolecular structures. PDBe also delivers enriched annotations contributed by the PDBe-Knowledge Base (PDBe-KB) consortium. The macromolecular entry pages are the primary interface for millions of users who explore experimental structure data. Here, we describe the redesign of the PDBe entry pages that organize content into logical views, thereby improving usability and facilitating the use of structure models, driving fundamental and applied research, and supporting education. The new design introduces several enhancements, including integrated and central 3D visualization, sequence feature exploration, standardized molecular scenes, AI-driven residue-level annotations from text mining of the literature, and streamlined annotation access via refactored APIs. Importantly, researchers can now upload their own residue-level features and visualize them directly in structural context, displayed alongside PDBe-KB annotations. This functionality enables scientists to interpret unpublished or private data in relation to high-quality structural information, lowering barriers for those without prior expertise in structural biology. Together, these updates create a more accessible, flexible, and scalable framework for interacting with structural data, expanding the resource’s value to both domain specialists and the wider life sciences community.
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December 10, 9:30 PM
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Helical protein–protein interactions underpin transcriptional regulation, signal transduction, and self-assembly, yet their rational design remains challenging. Coiled coils (CCs) are particularly attractive as modular, programmable building blocks in synthetic biology, while also serving as therapeutic targets. Here we present InsiliCoil, a cross-platform software suite that unifies predictive modeling, selective peptide inhibitor discovery, and orthogonal interactome design into a single accessible framework. At its core, isCAN enables high-throughput identification of selective CC inhibitors, while CCIS systematically constructs orthogonal CC networks for synthetic biological circuits and biomaterials. Additional utilities support automatic heptad detection, heptad scanning, constraint analysis, charge block prediction, library generation, and large-scale visualization. Benchmarking against experimental data sets confirms that InsiliCoil reliably recovers validated inhibitors and interactomes, while offering orders-of-magnitude faster throughput than structure-based approaches. By providing a cohesive, user-friendly platform for controlling helix-mediated PPIs, InsiliCoil accelerates both therapeutic discovery and the rational engineering of programmable biological systems.
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December 10, 4:43 PM
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Drug-resistant bacterial infections, exacerbated by antibiotic resistance and biofilm resilience, disrupt tissue repair through dysregulated inflammation and impaired regeneration. Neutrophil extracellular traps (NETs) play a crucial role in endogenous immunity by entrapping and eliminating pathogens, inspiring the development of synthetic biomaterials that replicate this function. However, current synthetic NETs face challenges in complexity, biocompatibility, structural integrity and effectiveness. Here, we present a NETs-mimicking hydrogel composed of reversible lysozyme amyloid flexible nanofibrils (FFs) enabling pathogen elimination and tissue regeneration. The FFs therein self-assemble from natural egg-white lysozyme endowing these nanoNETs with bioactivity against pathogens, and when duly labeled to respond to near-infrared irradiation, they disassemble into unfolded lysozyme monomers with antimicrobial activity. Notably, the hydrogel disassembly is followed by the controlled release of pre-dissolved Mg²⁺ ions, reprogramming macrophages toward a pro-regenerative phenotype and mitigating inflammation. In both murine and porcine models, these biocompatible nanoNETs demonstrate excellent antibacterial performance, accelerating healing of wounds infected by methicillin-resistant Staphylococcus aureus (MRSA). Moreover, these nanoNETs boost in-vivo healing of MRSA-infected periprosthetic joints, preserving osteogenic and regenerative microenvironments. These results build on the reversible nature of flexible amyloids to introduce stimuli-responsive biocompatible nanoNETs with significant potential for antimicrobial and regenerative therapies in bacterial-resistant infections. Drug-resistant bacterial infections hinder tissue repair and regeneration. Here, authors present a lysozyme nanofibril-based hydrogel that mimics neutrophil extracellular traps, enabling pathogen elimination and promoting tissue regeneration.
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December 10, 12:54 PM
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DNA methylation is a crucial epigenetic mechanism that regulates gene expression. Precise editing of DNA methylation has emerged as a promising tool for dissecting its biological function. However, challenges in delivery have limited most applications of DNA methylation editing to in vitro systems. Here, we develop two transgenic mouse lines harboring an inducible dCas9-DNMT3A or dCas9-TET1 editor to enable tissue-specific DNA methylation editing in vivo. We demonstrate that targeted methylation of the Psck9 promoter in the liver of dCas9-DNMT3A mice results in decreased Pcsk9 expression and a subsequent reduction in serum low-density lipoprotein cholesterol level. Targeted demethylation of the Mecp2 promoter in dCas9-TET1 mice reactivates Mecp2 expression from the inactive X chromosome and rescues neuronal nuclear size in Mecp2+/- mice. Genome-wide sequencing analyses reveal minimal transcriptional off-targets, demonstrating the specificity of the system. These results demonstrate the feasibility and versatility of methylation editing, to functionally interrogate DNA methylation in vivo. Precise editing of DNA methylation has emerged as a promising tool in disease biology but most applications are limited to in vitro systems. Here, we develop two transgenic mouse lines harboring an inducible dCas9-DNMT3A or dCas9-TET1 editor to enable tissue-specific DNA methylation editing in vivo.
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December 10, 12:47 PM
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The incidence of cardiometabolic diseases is increasing globally, and both poor diet and the human gut microbiome have been implicated. However, the field lacks large-scale, comprehensive studies exploring these links in diverse populations. Here, in over 34,000 US and UK participants with metagenomic, diet, anthropometric and host health data, we identified known and yet-to-be-cultured gut microbiome species associated significantly with different diets and risk factors. We developed a ranking of species most favorably and unfavorably associated with human health markers, called the ‘ZOE Microbiome Health Ranking 2025’. This system showed strong and reproducible associations between the ranking of microbial species and both body mass index and host disease conditions on more than 7,800 additional public samples. In an additional 746 people from two dietary interventional clinical trials, favorably ranked species increased in abundance and prevalence, and unfavorably ranked species reduced over time. In conclusion, these analyses provide strong support for the association of both diet and microbiome with health markers, and the summary system can be used to inform the basis for future causal and mechanistic studies. It should be emphasized, however, that causal inference is not possible without prospective cohort studies and interventional clinical trials. Comprehensive large-scale studies of multi-national populations identified microbiome species consistently associated with favorable and unfavorable health markers, informing future studies of the human gut microbiome and its association with diet and cardiometabolic conditions.
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December 10, 12:18 PM
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Nanopore sequencing has emerged as a powerful technology for DNA methylation detection, particularly in repetitive genomic regions and at the haplotype scale. However, existing computational methods show inconsistent accuracy across sequence contexts, species, and sequencing chemistries. Here, we present Unimeth, a unified transformer-based framework that simultaneously predicts multi-site methylation from nanopore reads. Unimeth employs a patch-based architecture and a three-phase training strategy, including pre-training, read-level fine-tuning, and site-level calibration, to fully leverage genome-wide methylation information. In comprehensive benchmarks involving 20 samples spanning 13 species, Unimeth consistently outperforms state-of-the-art methods. This unified approach demonstrates superior accuracy and significantly reduced false positives across a wide range of scenarios, including the detection of both 5mC and 6mA, application in organisms from mammals and plants to bacteria, analysis of both wild-type and mutant samples, and use of both R10.4 and R9.4 pore chemistries. Furthermore, Unimeth is demonstrated to be a highly accurate tool for methylation analysis in transposons and centromeric regions.
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December 10, 12:04 PM
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Fluorescent pseudomonads catabolize purines via uric acid and allantoin, a pathway whose end-product is glyoxylate. In this work, we show that in Pseudomonas aeruginosa strain PAO1, the ORFs PA1498–PA1502 encode a pathway that converts the resulting glyoxylate into pyruvate. The expression of this cluster of ORFs was stimulated in the presence of allantoin, and mutants containing transposon insertions in the cluster were unable to grow on allantoin as a sole carbon source. The likely operonic structure of the cluster is elucidated. We also show that the purified proteins encoded by PA1502 and PA1500 have glyoxylate carboligase (Gcl) and tartronate semialdehyde (TSA) reductase (GlxR) activity, respectively, in vitro. Gcl condenses two molecules of glyoxylate to yield TSA, which is then reduced by GlxR to yield d-glycerate. GlxR displayed much greater specificity (kcat/KM) for Gcl-derived TSA than it did for the TSA tautomer, hydroxypyruvate. This is relevant because TSA can potentially spontaneously tautomerize to yield hydroxypyruvate at neutral pH. However, kinetic and [1H]-NMR evidence indicate that PA1501 (which encodes a putative hydroxypyruvate isomerase, Hyi) increases the rate of the Gcl-catalysed reaction, possibly by minimizing the impact of this unwanted tautomerization. Finally, we use X-ray crystallography to show that apo-GlxR is a configurationally flexible enzyme that can adopt two distinct tetrameric assemblies in vitro.
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Today, 12:10 AM
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The synthesis of human genomes and other gigabase-scale genomes will require new strategies. Here, we realized key steps in our pipeline for building synthetic human chromosomes. We established: (i) the facile transfer of human chromosomes from human cells to mouse embryonic stem cells (assembly cells), where they are haploid, are nonessential, and may be operated on; (ii) the transfer of these human chromosomes from monochromosomal hybrids back into human cells to generate defined, synthetic aneuploidies; and (iii) the elimination of the corresponding endogenous human chromosomes to regenerate diploid cells containing a transferred chromosome. All steps were performed in nontransformed cells without chromothripsis and generated minimal structural variants, insertions, deletions, or single-nucleotide variants.
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December 10, 11:44 PM
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R-pyocins are phage tail-like protein complexes produced by Pseudomonas aeruginosa that deliver a single, lethal hit by depolarizing the target cell membrane. Unlike phages, R-pyocins lack capsids and DNA, and their killing is highly specific, being determined by tail fibre proteins that recognize subtype-specific LPS receptors on susceptible strains. Five known subtypes (R1–R5) vary in host range, with R5 displaying the broadest activity. R-pyocin expression is tightly regulated by the SOS response, linking their release to environmental stress. Their non-replicative mechanism and metabolic independence make them especially promising for targeting multidrug-resistant and biofilm-associated P. aeruginosa infections, such as those seen in cystic fibrosis and chronic wounds. Preclinical studies support their therapeutic potential, and bioengineering approaches have extended their target range. With their high specificity, rapid action and adaptability, R-pyocins are strong candidates for next-generation precision antimicrobials.
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December 10, 11:23 PM
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As biology grows increasingly data-driven, so too does the field of phage lysins, enzymes that degrade bacterial cell walls and hold promise as alternatives to traditional antibiotics. Five years ago, we introduced PhaLP, a centralized resource for Phage Lytic Protein sequences and associated metadata to support global research efforts. Here, we present PhaLP 2.0, a significantly enhanced database designed to overcome key challenges in the computational study of lysins by integrating the newly identified lysins obtained from thousands of metagenomes. To expand the known diversity of lysins beyond those from cultured phages, we developed SUBLYME, a protein embedding-based machine learning Software designed to Uncover and classify Bacteriophage Lysins in Metagenomic datasets. Using embeddings derived from the prior well-curated protein sequences of the original PhaLP database, we trained support vector machines to distinguish lysins from non-lysins in viromes and classify them as either endolysins or virion-associated lysins. The models achieved an average F1-score of 98% on held-out lysin clusters. SUBLYME enabled the discovery of 743,000 new lysin sequences from EnVhogDB, a virome-derived protein database, increasing the number of known lysin clusters by a factor of 40, from 1,000 to 40,000. PhaLP 2.0 entries were annotated by integrating Pfam functional predictions to the refined delineations obtained with SPAED, an algorithm that leverages the predicted aligned error matrix from AlphaFold predictions to identify domain boundaries. Both SUBLYME and the PhaLP 2.0 database are accessible online at https://github.com/Rousseau-Team/sublyme and http://phalp.ugent.be, respectively. Together, these advances establish PhaLP 2.0 as a comprehensive and scalable portal for the discovery, classification, and sequence analysis of phage lysins, paving the way for future antibacterial applications and evolutionary insights.
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December 10, 11:04 PM
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Phage therapy has received great attention as a promising antimicrobial treatment, and its core technique, namely predicting phage–bacterium interactions (PBIs), is crucial for understanding infection mechanisms and optimizing therapeutic strategies. However, existing computational methods mainly focus on the species or higher taxonomic levels, and usually neglect the potential of deep embedding representations, limiting their ability to capture complex biological patterns inherent in sequences. This hinders the discovery of rich sequence features, and restricts the clinical application of phage therapy. To address these limitations, we propose a novel deep learning framework (called PBIP) for strain-level PBI prediction. In PBIP, we first identify strain-level interactions through biological infection experiments and sequencing of Klebsiella pneumoniae isolated from the clinical environment of Xiangya Hospital. Then, we utilize a pretrained unified representation model to convert protein sequences of phages and bacteria into deep embeddings. Next, we apply the synthetic minority oversampling technique to generate positive interactions in the embedding space to address the data imbalance issue. Subsequently, we design a deep neural network that uses a convolutional neural network to extract local features, a bi-directional gated recurrent unit to capture global features, and an attention module to highlight significant features. Finally, a fully connected layer integrates this information for PBI prediction. Experimental results show the superiority of PBIP over the state-of-the-art methods in predicting PBIs. The code and datasets are available at https://github.com/a1678019300/PBIP.
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December 10, 10:47 PM
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All genomes have mobile genetic segments called transposable elements (TEs). Here we describe a system, which we term SOS splicing, that protects Caenorhabditis elegans and human genes against DNA-transposon-mediated disruption by excising these TEs from host mRNAs. SOS splicing, which seems to operate independently of the spliceosome, is a pattern-recognition system triggered by the base-pairing of inverted terminal repeat elements, which are a defining feature of DNA transposons. We identify three factors required for SOS splicing in both C. elegans and human cells: AKAP17A, which binds TE-containing mRNAs; the RNA ligase RTCB; and CAAP1, which bridges RTCB and AKAP17A to allow RTCB to ligate mRNA fragments generated by TE excision. We propose that SOS splicing is a previously undescribed conserved and RNA-structure-directed mode of mRNA splicing, and that an identified function of SOS splicing is to genetically buffer animals from the deleterious effects of DNA-transposon-mediated gene perturbation. A new type of mRNA splicing mechanism discovered in Caenorhabditis elegans that detects and removes inverted repeats also occurs in human cells, thereby providing another strategy to protect against the negative effects of transposable elements.
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December 10, 10:36 PM
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Module swapping is an emerging strategy for creating transcriptional regulators with tailored combinations of signal detection and promoter recognition. By hybridizing DNA-binding modules (DBMs) and ligand-binding modules (LBMs) from the same protein family, resulting regulators can be harnessed to establish new genetic connections. This approach has been applied to a range of regulator families; however, a portion of resulting hybrid regulators are poorly functional, which can be due to incompatibility between DBMs and LBMs, as critical module–module interactions are lost after hybridization. To address this issue, we developed an approach to design modular regulators and applied it to the TtgR/AcrR regulator family. Our approach involves identifying key residue pairs for DBM–LBM interactions by statistical analyses of coevolutionary traits among family members and experimental results from hybrid regulator characterization. These residue pairs were harnessed to develop a computational model for predicting compatibility between DBMs and LBMs. Using this predictive model, we designed mutations to reinstall critical interactions, which rescued protein activities. These hybrid regulators were harnessed to construct a genetic circuit for a three-input logic AND operation, demonstrating that our approach is effective for studying and designing new TtgR/AcrR modular regulators.
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December 10, 10:02 PM
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Horizontal gene transfer (HGT) accelerates the spread of antimicrobial resistance (AMR) via mobile genetic elements allowing pathogens to acquire resistance genes across species. This process drives the evolution of multidrug-resistant “superbugs” in clinical settings. Detection of HGT is critical to mitigating AMR, but traditional methods based on sequence assembly or comparative genomics lack resolution for complex transfer events. While machine learning (ML) promises improved detection, several studies in other domains have demonstrated that data representations will strongly influence its performance. There is, however, no clear recommendation on the best data representation for HGT detection. Here, we evaluated 44 genomic data representations using five ML models across four data sets. We demonstrate that ML performance is highly dependent on the genomic data representation. The RCKmer-based representation (k = 7) paired with a support vector machine is found to be optimal (F1: 0.959; MCC: 0.908), outperforming other approaches. Moreover, models trained on multi-species data sets are shown to generalize better. Our findings suggest that genomic surveillance benefits from task-specific genome data representations. This work provides state-of-the-art, fine-tuned models for identifying and annotating genomic islands that will enable proper detection of transfer of AMR-related genes between species.
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December 10, 5:03 PM
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Steroids are among the most valuable and widely used pharmaceuticals. The cholesterol side-chain cleavage enzyme (P450scc) is critical for steroid metabolism and hormone biosynthesis. While mammalian eukaryotic P450scc enzymes are well-characterized, bacterial counterparts remain underexplored despite their industrial promise and potential contributions to bacterial steroid catabolism. Here, we identify a series of CYP204 family P450 enzymes, widely distributed across diverse steroid-degrading bacterial species, that catalyze the side-chain cleavage of cholesterol, phytosterol, and cholestenone to produce pregnenolone and progesterone. Unlike mammalian enzymes, which exhibit strict cholesterol specificity, bacterial P450scc enzymes display relaxed substrate specificity, preferentially converting cholestenone to progesterone—a key precursor in steroid drug semi-synthesis. Structural and mechanistic analyses demonstrate that CYP204 enzymes employ a flexible, dual-regioselective C–H activation mechanism distinct from the sequential hydroxylation of mammalian P450scc enzymes. Iterative saturation mutagenesis identified critical residues for side-chain cleavage, improving catalytic efficiency up to 6.5-fold, and computational analyses clarified sequence–function relationships. This finding of bacterial P450scc enzymes not only underscores their potential function in bacterial steroid catabolism but also lays a foundation for promising biocatalytic strategies for pregnenolone and progesterone synthesis. Genome mining identified bacterial P450 that cleave cholesterol side-chains via dual C-H activation, differing from mammalian P450scc. Engineered CYP204A5 efficiently converts cholestenone to progesterone for biocatalysis.
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December 10, 1:18 PM
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Self-assembly is a fundamental property of living matter that drives the three-dimensional organization of cell collectives such as tissues and organs. Here, the co-assembly of synthetic and natural cells is leveraged to create hybrid living 3D cancer cultures. We screen a range of synthetic cell models for their ability to form augmented tumoroids with artificial but controllable micro-environments, and show that the balance of inter- and extracellular adhesion and synthetic cell surface tension are key material properties driving integrated co-assembly. We demonstrate that synthetic cells based on droplet-supported lipid bilayers can establish artificial tumor immune microenvironments (ART-TIMEs), mimicking immunogenic signals within tumoroids and eliminating the need to integrate complex living immune cells. Using the ART-TIME approach, we identify a AhR-ARNT-mediated co-signaling mechanism between PD-1 and CD2 as a driver in immune evasion of pancreatic ductal adenocarcinoma. Our study advances the field of hybrid organoid engineering, offers opportunities for the construction and modelling of artificial tumour environments, and marks a step towards the design of functional living/non-living cytomimetic materials. Synthetic cells have huge potential in model systems. Here, the authors engineer synthetic–living hybrid tumoroids that replicate tumour-immune interactions in 3D, study synthetic cells integration, and demonstrate systematic studies of immune evasion and T cell engager therapies.
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December 10, 12:49 PM
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Transcription factors regulate gene expression by binding specific DNA motifs, yet only a fraction of putative sites is occupied in vivo. Intrinsically disordered regions have emerged as key contributors to promoter selectivity, but the underlying mechanisms remain incompletely understood. Here, we use single-molecule optical tweezers to dissect how disordered regions influence DNA binding by Msn2, a yeast stress-response regulator. We show that these regions power a search mechanism, facilitating initial non-specific association with DNA and promoting one-dimensional scanning toward target motifs, supported by charge-mediated interactions. Remarkably, this mechanism displays sequence sensitivity, with promoter-derived sequences enhancing both initial binding and scanning rates, demonstrating that Msn2–DNA interactions alone are sufficient to confer promoter selectivity in the absence of chromatin or cofactors. Our findings provide direct mechanistic evidence for how intrinsically disordered regions tune transcription factor search dynamics for Msn2 and expand sequence recognition beyond canonical motifs, supporting promoter selectivity in complex genomic contexts. The study reveals how intrinsically disordered regions enable a yeast transcription factor to locate and selectively bind its target promoters by promoting DNA association outside its motif and sequence-dependent search dynamics.
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December 10, 12:20 PM
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The metal-binding periplasmic protein CusF has been proposed as a bifunctional tag enhancing solubility of recombinant proteins and enabling purification using Cu affinity chromatography. However, evidence for its performance remains limited to a few model proteins. Here, we evaluated CusF as a solubility tag for two heterologous proteins: a putative poly(A)-polymerase from Enterococcus faecalis (Efa PAP) and the red fluorescent protein mCherry. The proteins were fused to CusF, expressed in E. coli BL21 (DE3) pLysS and Rosetta 2 (DE3) strains, and assessed for solubility and IMAC binding. Native Efa PAP was completely insoluble under all tested conditions, and fusion to CusF did not improve its solubility. Similarly, CusF-mCherry accumulated predominantly in the insoluble fraction, with only traces detectable in soluble lysates. Soluble CusF-mCherry did not bind Cu2+-charged IMAC resin, while moderate binding to Ni2+-charged resin was attributable to the vector-encoded His-tag rather than CusF. These results indicate that CusF does not universally enhance protein solubility and may not always bind Cu-based IMAC resin. Our findings expand empirical knowledge on solubility tag performance and emphasize the necessity of testing multiple tags to identify optimal strategies for recombinant protein production.
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December 10, 12:15 PM
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Mannose has wide-ranging applications but microbial fermentation remains underdeveloped compared to biotransformation for its production. The yeast Komagataella phaffii stands out as a premier synthetic biology platform, renowned for its safety profile and exceptional suitability for high-density fermentation. This established chassis organism is ideally positioned for large-scale mannose production through targeted rewiring of its mannose biosynthetic pathway via metabolic engineering. K. phaffii was metabolically engineered for efficient mannose production using a dual carbon source system: glycerol for biomass generation and glucose for mannose synthesis. To redirect carbon flux toward fructose-6-phosphate (F6P) accumulation at the glycolytic node, glycolytic flux was attenuated by knocking out the phosphofructokinase II (pfk2) gene and downregulating phosphofructokinase I (pfk1). Simultaneously, pentose phosphate pathway flux was reduced by downregulating glucose-6-phosphate dehydrogenase (zwf1). To enhance mannose biosynthesis, conversion of F6P into mannose was promoted by suppressing phosphomannose isomerase (PAS_chr3_1115) and overexpressing the Escherichia coli-derived phosphatase gene yniC. Additionally, three genes involved in arabinitol and ribitol production (PAS_chr2–2_0019, PAS_chr4_0754, and PAS_chr4_0988) were deleted to suppress byproduct accumulation. The engineered strain achieved ~ 121.1 g/L mannose in high-cell-density, fed-batch fermentation, representing the highest reported titer via microbial fermentation to date. This study achieved efficient mannose production in K. phaffii by remodeling central metabolism. It not only offers a new route for mannose biosynthesis but also establishes a model framework for engineering K. phaffii to produce other high-value bioactive compounds.
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create an auxotrophic strain by disabling the thyA gene in the WT B. thetaiotaomicron. This gene encodes thymidylate synthase, crucial for DNA synthesis and repair. When disabled, the strain can grow only with added thymidine