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A Discrete Language of Protein Words for Functional Discovery and Design | brvai

A Discrete Language of Protein Words for Functional Discovery and Design | brvai | RMH | Scoop.it

Proteins function through hierarchical modules, yet conventional models treat sequences as linear strings of residues, overlooking the recurrent multi-residue patterns-or "Protein Words"-that govern biological architecture. We introduce a physics-aware framework that discretizes protein space into a learnable vocabulary derived from the evolutionary record. By encoding proteins as sequences of discrete "words," our model captures higher-order structural and functional signals inaccessible to residue-level models, achieving highly competitive performance against widely established baselines in remote homology and mutation effect prediction. Analysis across 54 species reveals that these words track evolutionary complexity, specifically identifying the expansion of eukaryotic disordered regions. We demonstrate the discovery potential of this semantic axis by identifying ADMAP1 as a previously uncharacterized regulator of sperm motility, validated via CRISPR-Cas9 knockout mice. Finally, this vocabulary enables programmable design, generating functional cofilin variants despite high sequence divergence. This work establishes a linguistically inspired framework for deciphering the dark proteome and engineering biological function.

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Particle-associated diazotrophs drive nitrogen fixation in Arctic subsurface waters of the Barents Sea | Ncm

Particle-associated diazotrophs drive nitrogen fixation in Arctic subsurface waters of the Barents Sea | Ncm | RMH | Scoop.it

Biological dinitrogen (N2) fixation sustains productivity in oligotrophic oceans and is now also thought to contribute substantially to the nitrogen supply in the warming Arctic. Here we demonstrate significant N2 fixation by particle-associated diazotrophs in subsurface waters of the Barents Sea. Comparing our findings with subtropical studies reveals particle-associated non-cyanobacterial diazotrophs as the primary N2 fixers in subsurface Arctic waters of the Barents Sea, contrasting with diverse communities in warmer regions. As the Arctic shifts towards oligotrophication, understanding the magnitude and controls of particle-associated N2 fixation will provide critical insights into future nitrogen supply required to sustain productivity in the rapidly changing Arctic Ocean. However, particle-associated N2 fixation may be a distinctive feature of the Barents Sea, where in contrast to other Arctic shelves the seasonal and long-term trends in nitrogen dynamics are heterogeneously determined by changes in the external Atlantic Water supply, sea-ice extent, and terrestrial inputs. In this context, the role of particle-associated N2 fixation across the wider Arctic Ocean will require further investigation. The study shows that particle-associated non-cyanobacterial diazotrophs dominate nitrogen fixation in subsurface Barents Sea waters, contrasting with warmer oceans and highlighting an important Arctic source of new nitrogen for productivity.

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Immune protection and persistence in Pseudomonas aeruginosa infections by pyruvate cross-feeding | Ncm

Immune protection and persistence in Pseudomonas aeruginosa infections by pyruvate cross-feeding | Ncm | RMH | Scoop.it

Chronic infections by Pseudomonas aeruginosa in people with cystic fibrosis are characterized by persistent inflammation and oxidative stress, yet the mechanisms enabling bacterial persistence are not fully understood. Here, we identify a persistence mechanism mediated by pyruvate secretion resulting from mutations in the pyruvate dehydrogenase complex in clinical isolates of P. aeruginosa, with putative analogous mutations also identified in Staphylococcus aureus, Haemophilus influenzae and Stenotrophomonas maltophilia. These mutations lead to elevated extracellular pyruvate, which dampens host inflammatory responses and favors bacterial persistence. Pyruvate exerts multiple roles: scavenges reactive oxygen species such as H2O2, suppresses host immune activation both in airway epithelial cells and macrophages, and increases bacterial survival during phagocytosis. This metabolic crosstalk promotes bacterial persistence while reducing epithelial and macrophage inflammatory responses. Our findings reveal pyruvate as a bacterial immunometabolite that mimics host antioxidant defenses, reshaping the infection niche to favor long-term colonization. This work highlights the broader role of secreted metabolites in host-pathogen interactions and suggests new strategies targeting metabolic pathways to manage chronic infections. The study shows that metabolic mutations in Pseudomonas aeruginosa lead to pyruvate secretion, which reduces oxidative stress, dampens immune responses, promoting bacterial survival and persistence in chronic airway infection.

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Structural and Functional Characterization of Heterologous Nitrogenase Complexes | acs

Structural and Functional Characterization of Heterologous Nitrogenase Complexes | acs | RMH | Scoop.it

Nitrogenase is the only known enzyme that catalyzes the reduction of dinitrogen to ammonia. The most prevalent isozyme, molybdenum nitrogenase, comprises the catalytic molybdenum–iron protein (MoFeP) and the ATP-dependent reductase iron protein (FeP). Although Mo-nitrogenases are widespread across bacteria and archaea and appear to share conserved mechanistic and structural features, FeP and MoFeP show considerable sequence variability across diazotrophs. This raises questions about the conservation of chemomechanical mechanisms coupling FeP-dependent ATP hydrolysis and electron transfer to MoFeP, and about the functional compatibility of nitrogenase components from divergent species. Previous studies showed that some heterologous FeP−MoFeP pairs can functionally complement each other, whereas other pairs lack catalytic activity, but the absence of structural information on such heterologous pairs has limited mechanistic understanding. To this end, we investigated the functional and structural compatibility of FeP and MoFeP from Azotobacter vinelandii (Av) and Gluconacetobacter diazotrophicus (Gd), two phylogenetically and ecologically distinct species. Building on our prior work with Gd-nitrogenase and recently developed cryogenic electron microscopy (cryoEM) protocols, we determined the ADP·BeFx-trapped structure of the homologous GdFeP–GdMoFeP complex and showed that it adopted the same geometry as its Av counterpart. Activity measurements showed that heterologous Gd/Av combinations retained 60–80% of homologous catalytic activities despite 30–50% sequence divergence in FeP and MoFeP. High-resolution cryoEM structures of GdFeP–AvMoFeP and AvFeP–GdMoFeP corroborated these activities and revealed that functional complementation tolerates substantial sequence variation when the core structural elements supporting ATP binding/hydrolysis, protein–protein interaction, electron transfer, and substrate reduction are conserved.

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chimera

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Polyhydroxyalkanoate-Based Fertilizers for Phosphorus Slow Release | acs

The exploration and use of biodegradable polymers to develop both environmentally and agronomically efficient slow-release fertilizers are rapidly growing. Polyhydroxyalkanoates (PHAs) are biodegradable polymers produced by microorganisms. Among agricultural soil-treatment solutions, they are mainly used as carrier agents for pesticide and herbicide formulations. In this study, PHA-based orthophosphate (OrthoP) fertilizers were developed using extrusion to enable slow release of P. The pellets were characterized in terms of elemental composition, morphology, specific gravity and bulk density, water vapor sorption, and attrition resistance. The P release kinetics in water was monitored, and the effects of extruded pellets on the germination index and dry biomass of tomato, as well as their disintegration in the soil, were assessed. The results demonstrated mechanical performance enhanced by more than 10% and water half-release times ranging from 0.5 h for the initial pellet to 140 h for the slowest-releasing pellet. These improvements could optimize P fertilizer efficiency under field conditions, aligning with the principles of precision agriculture.

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phb

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A Genetically Encoded Fluorescent Sensor for Protein Arginine Phosphorylation | acs

A Genetically Encoded Fluorescent Sensor for Protein Arginine Phosphorylation | acs | RMH | Scoop.it

Protein arginine phosphorylation (pArg) is an important but underexplored post-translational modification (PTM). In Gram-positive bacteria, pArg serves as a “degron” to guide damaged proteins for degradation by the ClpCP protease. Accordingly, enzymes that regulate pArg have been investigated as potential therapeutic targets against drug-resistant bacteria. Despite its importance, monitoring pArg dynamics remains technically challenging due to the chemical instability of pArg, with no methods available for live-cell studies. To address this, we developed a genetically encoded fluorescent sensor, FLAP (FLuorescent Arg Phosphorylation sensor), based on FRET to monitor the activity of the arginine kinase McsB and the pArg phosphatase YwlE. FLAP exhibited reversible, real-time FRET changes upon arginine phosphorylation and dephosphorylation in vitro. In an orthogonal E. coli system, FLAP successfully detected McsB-dependent pArg formation upon expression of active McsB. These results establish FLAP as a genetically encoded platform for studying pArg-writing and pArg-erasing enzymes in vitro and provide a proof of concept for live-cell detection of Arg phosphorylation.

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1str, kinase sensor

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A Fungal Bioluminescent Pathway (FBP)-Based Yeast Biosensor for Caffeic Acid Quantification in Food and Beverages | acs

A Fungal Bioluminescent Pathway (FBP)-Based Yeast Biosensor for Caffeic Acid Quantification in Food and Beverages | acs | RMH | Scoop.it

Caffeic acid is a natural hydroxycinnamic acid widely distributed in plant tissues and abundant in the human diet through fruits, vegetables, and a variety of plant-based beverages. This compound exhibits strong antioxidant, metal-chelating, and biological activities, being one of the most studied phenylpropanoids for therapeutic and biotechnological applications. The discovery of the fungal bioluminescent pathway (FBP), which converts caffeic acid into visible light through enzymatic luciferin biosynthesis followed by luciferase-catalyzed oxidation, has opened new opportunities for bioanalytical applications. In this work, we developed a simple, fast, and low-cost methodology to detect and quantify caffeic acid using Komagataella phaffii cells expressing the FBP enzymes. The system is based on bioluminescent light emission and, under optimized assay conditions with the working buffer (50 mM phosphate buffer containing 1% YPD, pH 6.0, and a yeast cell density of OD600 = 5), achieved LODs ranging from 1.4 to 19.1 μM and LOQs ranging from 4.3 to 57.9 μM in six commercial beverage matrices. Using only a few microliters of sample, we rapidly quantified caffeic acid in roasted coffee (0.05 mg/g) and yerba mate (Ilex paraguariensis, 11.1 mg/g) infusions; red and white wines (8.9–15.4 and 3.6–6.3 mg/L, respectively); wildflower honey (11.6 mg/kg); and grape juice (6.5–8.5 mg/L). The whole-cell bioluminescent approach for caffeic acid quantification provides a sustainable and accessible alternative to conventional chromatographic or electrochemical methods, reducing environmental impact while preserving analytical reliability.

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caffeic acid sensor

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BiMba: using Vision Mamba to predict protein sites that bind other proteins | bft

BiMba: using Vision Mamba to predict protein sites that bind other proteins | bft | RMH | Scoop.it

Identifying protein binding sites in protein–protein complexes is a central challenge in structural biology. Binding sites, consisting of groups of residues, govern how proteins recognize, and interact with protein partners. Thus, identifying them is essential for understanding biological function and guiding the design of effective biomolecules and even drug molecules. Despite major progress in computational approaches, their performance remains limited because most models underrepresent the combined influence of surface properties and residue-level information, leaving room for improvement. Recent advances in state-space models and vision-based deep learning offer an opportunity to address these limitations by efficiently modeling long-range spatial dependencies on protein surfaces. Here, we introduce BiMba (protein Binding site prediction using Vision Mamba), a state-space–driven deep learning framework that leverages the efficient long-range modeling capability of the Vision Mamba architecture to learn from three-dimensional (3D) protein surfaces represented as two-dimensional (2D) geometric or physicochemical grids. BiMba integrates complementary sources of information, capturing geometric and physicochemical determinants of molecular recognition as surface patches, encoded as 2D images, along with residue-level descriptors, yielding a unified representation that couples spatial topology with biochemical context. BiMba demonstrates competitive performance across diverse and specialized benchmark datasets, often outperforming existing state-of-the-art methods. In addition, BiMba incorporates perturbation-based and gradient-based interpretability analyses by extracting hidden attentions from Mamba layers, enabling visualization of feature relevance and biologically meaningful residue clusters. Overall, our findings establish state-space models as efficient, interpretable, and scalable architectures for molecular surface learning, advancing the application of deep learning in structural bioinformatics.

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ppi

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Discovery of potent low-toxicity antimicrobial peptides through diffusion modeling | Ncm

Discovery of potent low-toxicity antimicrobial peptides through diffusion modeling | Ncm | RMH | Scoop.it

The rapid emergence of multidrug-resistant bacteria has created an urgent need for improved antimicrobial discovery and screening platforms. Here, we present ARCADIAMP, a generative and virtual screening platform that couples an iterative-learning discrete denoising diffusion probabilistic model with a two-stage Evolutionary Scale Modeling 2 (ESM2)-based antibacterial activity classifier to generate, classify, and prioritize potent AMPs with high activity, low toxicity, and favorable serum stability. Eight of the ten experimentally screened peptide candidates showed antimicrobial activity (MIC ≤ 32 μg/mL), while one generated candidate, Arcinin, demonstrated strong activity against ESKAPE pathogens (MIC 8–32 μg/mL), low hemolytic activity (LC50 > 512 μg/mL for human red blood cells), and strong serum-retained activity (MIC 32 μg/mL in 50% bovine serum for four ESKAPE species). Electron microscopy, membrane depolarization assays, time-kill kinetics, and molecular dynamics simulations showed that Arcinin acts through sub-microsecond insertion and penetration consistent with the behavior of other well-known AMPs. In a bacteria-infected wound murine model, Arcinin achieved a 4-log reduction in bacterial burden, which facilitated subsequent re-epithelialization and wound recovery. By framing antimicrobial discovery as an AI-assisted iterative optimization problem, ARCADIAMP links activity, toxicity, and efficacy and provides a scalable template for discovering therapeutically promising biologics. In this study, Markakis et al. use a generative AI model to design antimicrobial peptides that are both potent and safe. Their lead candidate, Arcinin, kills drug-resistant bacteria, spares human cells, and clears infection in a mouse wound model.

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generate amp

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QutRNA2: robust tRNA modification discovery from Nanopore direct tRNA sequencing | nar

QutRNA2: robust tRNA modification discovery from Nanopore direct tRNA sequencing | nar | RMH | Scoop.it

Transfer RNAs (tRNAs) are essential for protein synthesis and are extensively modified to ensure their structure and function. Direct RNA sequencing with Oxford Nanopore Technologies enables positional modification analysis but is challenged by tRNAs’ short length, redundancy, and dense modifications. We present QutRNA2, a scalable workflow that includes GPU-accelerated local alignment, statistical filtering, pairwise error profile comparison, and customizable visualization. Achieving up to 25-fold speed gains over CPU methods, QutRNA2 identifies enzyme-dependent modifications in nuclear- and mitochondrial-encoded tRNAs, demonstrated in high-volume human and mouse samples. This open-source solution provides a comprehensive, multiplexing-compatible framework for tRNA analysis, addressing a key gap in current tools. QutRNA2 is released under Apache-2.0 license and is available at https://github.com/dieterich-lab/QutRNA2.

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Efficient CRISPR-Cas9 delivery and transgene-free multiplex genome editing in plants using cymbidium mosaic virus-derived vectors | tpj

Efficient CRISPR-Cas9 delivery and transgene-free multiplex genome editing in plants using cymbidium mosaic virus-derived vectors | tpj | RMH | Scoop.it

Virus-induced genome editing (VIGE) has become a useful method by enabling transient delivery of gene-editing reagents; however, many viral systems face limitations in cargo size, host range, or reliance on transgenic Cas9-expressing plants. In this study, we developed a cymbidium mosaic virus (CymMV)-based VIGE platform that enables simultaneous expression of Streptococcus pyogenes Cas9 (SpCas9) and one or more guide RNAs (gRNAs) from a single viral RNA. In Nicotiana benthamiana, this system induced editing in the Phytoene desaturase (PDS) gene, with indel rates exceeding 50% within 6 days after inoculation, outperforming traditional delivery methods by about fivefold. Notably, over 80% of regenerated plants contained targeted mutations, and 82% of these were both transgene- and virus-free, including tetra-allelic knockouts directly in the M0 generation. Adding a Ruby-based visual counterselection marker enabled rapid, reliable identification of transgene-free, edited plants without antibiotic selection. When adapted to Phalaenopsis aphrodite orchids, the platform efficiently edited the PaPDS gene, achieving a 47% indel frequency at 20 days post-inoculation, with visible bleaching in leaf tissue from inoculated protocorm-like bodies. Additionally, expressing multiple gRNAs from a single CymMV replicon enabled multiplex editing in orchid tissues, demonstrating the system's versatility for complex, polyploid crops. Our findings broaden the use of VIGE in orchids and provide a reliable framework for precision plant breeding.

mhryu@live.com's insight:

plant genome editing methods, (1) An infectious CymMV clone encoding SpCas9 + gRNA is introduced into Agrobacterium by electroporation. (2) Agroinfiltration delivers the viral cDNA into tissues of Nicotiana benthamiana or Phalaenopsis aphrodite. (3) Following viral replication in plant cells, subgenomic RNA transcription drives SpCas9 expression, while gRNA is concurrently produced from the viral replicon. (4) Cas9 associates with gRNA to form a ribonucleoprotein (RNP) complex that is transported into the nucleus, where it induces a double-strand break at the target locus. DNA repair via non-homologous end joining (NHEJ) results in indel mutations. (5) Edited tissues are regenerated. (6) Regenerated plants can be recovered as transgene-free and virus-free genome-edited lines. Detectable somatic editing occurs approximately 6 days post-inoculation in N. benthamiana and 20 days in P. aphrodite.

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Thermodynamically programmed one-pot CRISPR platform for point-of-care SNP genotyping | Ncm

Thermodynamically programmed one-pot CRISPR platform for point-of-care SNP genotyping | Ncm | RMH | Scoop.it

One-pot CRISPR diagnostics face a fundamental incompatibility: isothermal nucleic acid amplification enables rapid target accumulation, whereas CRISPR activation irreversibly consumes those substrates, destabilizing reaction kinetics. Here we show that reaction order can be programmed into DNA primers through thermodynamic design. Differences in primer-binding strength create two sequential amplification stages, delaying CRISPR activation until enough amplicons have accumulated without physical separation or external control. The design also introduces the protospacer adjacent motif (PAM), a short sequence required for CRISPR recognition, through the primer rather than relying on its presence in the native target, expanding target accessibility while retaining single-nucleotide discrimination. An ordinary differential equation model captures the threshold behavior and establishes a predictable framework for primer design. Building on this principle, we develop Thermodynamically Encoded Molecular Programming for One-pot diagnostics (TEMPO), which achieves attomolar sensitivity within 30 min and enables sequencing-concordant SNP genotyping and pathogen detection in a single-step microfluidic format. One-pot CRISPR diagnostics are limited by kinetic conflict between isothermal amplification and CRISPR detection. By thermodynamically programming reaction order into DNA primers, the authors create staged amplification enabling rapid, sensitive, single-step nucleic acid testing.

mhryu@live.com's insight:

once Cas12a recognizes a PAM-containing double-stranded amplicon, it undergoes "PAM-dependent cis-cleavage, followed by trans-cleavage of the reporter for signal generation. 
problem: one-pot RPA+Cas12a reaction, amplification and CRISPR activation happen simultaneously and compete for the same DNA molecules. As soon as any PAM-containing amplicon exists, Cas12a activates and starts destroying substrate via trans-cleavage
solution: FP (fully complementary primer): binds the target strongly and drives fast, efficient amplification, but produces PAM-free amplicons. This lets the reaction rapidly build up template concentration with zero competition from CRISPR activity.  FPP (mismatched primer): deliberately designed to bind more weakly (higher hybridization free energy penalty) and carries the PAM sequence. Because of the mismatch penalty, FPP can't compete for template until template concentration rises high enough that, per their thermodynamic relationship

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ThermoFusion: A Multimodal Deep Learning Framework for Generalizable Prediction of Enzyme Thermostability | brvai

Protein thermostability is a critical property for both industrial and biomedical enzyme applications, yet experimental evaluation of mutation-induced stability changes remains laborious and costly. Here, we present ThermoFusion, a hybrid deep learning framework that integrates 3D protein structure embeddings from ThermoMPNN with sequence-based embeddings from the pretrained protein language model ESM2 to predict the effects of single-point mutations on protein stability (ΔΔG). ThermoFusion exhibits robust generalization, maintaining high predictive accuracy across out of distribution sequences with low identity to the training set -- a scenario where many other machine learning models, including ThermoMPNN and state-of-the-art tools, perform poorly due to reliance on memorization. Benchmarking on a curated enzyme dataset comprising of 105 enzymes and 3144 mutations shows that ThermoFusion reliably identifies stabilizing mutations while accurately predicting stability for enzymes beyond its training set. These results establish ThermoFusion as a powerful tool for rational enzyme design beyond its training set.

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thermo

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Cas12a-Targeted Multiplexed Nanopore Sequencing | brvt

Cas12a-Targeted Multiplexed Nanopore Sequencing | brvt | RMH | Scoop.it

Targeted long read sequencing (LRS) of native genomic DNA (gDNA) using Oxford Nanopore Technologies (ONT) is an economically and computationally accessible method for sequencing selected genomic regions without the limitations associated with amplification-based approaches. At present, efficiency, multiplexing, and scalability remain key challenges for existing targeted LRS. We have developed Cas12a-Targeted Multiplexed Nanopore Sequencing (CTM-nSeq), which combines Cas12a-targeting, DNA fragment enrichment, and optimized adapter ligation using T7 DNA ligase. Unlike previously established protocols, CTM-nSeq is compatible with the latest ONT flow cell chemistry. Performing CTM-nSeq on a single sample with an R10.4 MinION flow cell routinely yields hundreds of on-target reads. Furthermore, CTM-nSeq enables targeting of multiple loci and is the first targeted ONT sequencing method, allowing reliable, barcode-assisted multiplexing. CTM-nSeq is an efficient and accessible method for sequencing native gDNA and analysing DNA methylation, repeat expansions, and sequence integrity. As such, CTM-nSeq has a wide range of analytical and diagnostic applications.

mhryu@live.com's insight:

sequence enrichment,
Dephosphorylate gDNA → cut the target sites with Cas12a (leaving new phosphorylated sticky ends) → run cut DNA on a low-percent agarose gel and excise/recover the desired fragment size range → ligate a custom linker matching the Cas12a overhang, using T7 ligase so only those cohesive ends get joined → ligate the ONT sequencing adapter onto the linker → load and sequence, so only the target fragment carries a usable adapter and gets read efficiently.

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Translation initiation by the Kozak mRNA sequence is based on a conformational readout on the ribosome | Ncm

Translation initiation by the Kozak mRNA sequence is based on a conformational readout on the ribosome | Ncm | RMH | Scoop.it

The recognition mechanism of Kozak mRNA, typically comprising purines in the −3 and +4 positions flanking the AUG start codon, has remained enigmatic for decades. To address this fundamental function in eukaryotes during translation initiation, we analysed several cryo-EM structures of human 48S preinitiation complexes with mRNA sequences differing in Kozak activity revealing distinct modes of recognition. The pre-codon triplet forms a fan-like intercalation into the 18S ribosomal RNA (rRNA), while a −3 pyrimidine destabilizes ternary complex positioning. Specificity towards the +4 purine is achieved beyond a single residue recognition by mutual conformational adaptations of eIF1A, mRNA and rRNA that involve the insertion of a reading head in which decoding residue A1825 (rRNA) stacks with the A-site codon to stabilize the fully accommodated state. Hence, instead of relying on base pairing as in bacteria, the specific recognition of the Kozak sequence on eukaryotic ribosomes is based on an induced-fit mechanism that triggers a conformational readout of the mRNA. The Kozak mRNA sequence is critical for protein synthesis in eukaryotes. Here, authors reveal that the molecular recognition of the Kozak sequence on the ribosome relies on an induced-fit mechanism that triggers a conformational readout of the mRNA.

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Engineering Modular Cargo Loading Strategies for Carboxysome-Derived Protein Particles | asb

Engineering Modular Cargo Loading Strategies for Carboxysome-Derived Protein Particles | asb | RMH | Scoop.it

Bacterial microcompartments (BMCs) are a diverse and widespread class of self-assembling protein-based organelles consisting of a semipermeable protein shell encapsulating an enzymatic core. Isolated BMC shell proteins have been shown to assemble into alternative superstructures such as flat sheets and nanotubes. The self-assembly and modularity of BMC shell proteins make them of great interest as modular platforms for applications involving scaffolding, immobilization, and compartmentalization. While the assembly of BMC shell proteins into higher-order structures has been well-studied, the design of controllable and modular cargo loading is underdeveloped in comparison. Recently, we reported the pH-controlled assembly of CcmK2, the major hexameric shell protein of the β-carboxysome BMC, into monodisperse mesh-like microscale particles. Here, we develop a suite of encapsulation strategies for stochastic or targeted loading of various cargos, as well as the direct conjugation of cargo to CcmK2 particles. Our systematic analysis demonstrates that cargo loading and particle assembly can be modulated by the choice of recruitment strategy and the order of cargo introduction. Our findings also reveal a cooperative cargo loading mechanism during assembly that influences particle sizing and apparent morphology. Our study serves as a blueprint for the rational design of tunable cargo loading into engineered BMC-derived microcompartment systems for diverse biotechnological applications.

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Microbiome-Based Framework for Achieving Simultaneous Efficient Transformation of Persistent Organic Pollutants and Restored Biogeochemical Cycling | acs

Microbiome-Based Framework for Achieving Simultaneous Efficient Transformation of Persistent Organic Pollutants and Restored Biogeochemical Cycling | acs | RMH | Scoop.it

Persistent organic pollutants (POPs), prevalent across diverse environmental matrices, are highly hazardous and recalcitrant compounds that can be transformed into low-toxicity compounds by diverse microorganisms. Many transformation processes of POPs could intricately interface with elemental biogeochemical cycles, which are fundamental drivers of ecosystem function. While microbial pathways of POPs transformation have been extensively studied, their integration into broader element turnover in the environment remains fragmented. Here, we review the relationship between POPs metabolism and biogeochemical cycles, spanning from single-species enzymatic coupling to multispecies syntrophic interactions. We contend that POPs transformation is not an isolated microbial event but is deeply embedded within elemental metabolism through direct mechanisms of electron transfer and cross-feeding, or indirect modulation of quorum sensing and mineral-interface interactions. Across levels from gene expression to community level-energy and material exchange, microorganisms in the environment mediate POPs transformation while maintaining elemental balance through dynamic metabolic regulation. Furthermore, we propose a strategic framework that leverages functional compensation and integrative strategies of native and engineered microbiomes to reinforce POPs degradation and coordinate element cycling. Future research should focus on integrating microbiome-based approaches with omics analyses, systems modeling, and ecological engineering. These efforts facilitate the predictable regulation of pollutant–element interactions, ultimately restoring ecosystem multifunctionality within POPs-contaminated sites.

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The Mycorrhizal Advantage: Boosting Medicinal Plant Bioactivities through Rhizosphere Enrichment | acs

The Mycorrhizal Advantage: Boosting Medicinal Plant Bioactivities through Rhizosphere Enrichment | acs | RMH | Scoop.it

The application of arbuscular mycorrhizal fungi represents a sustainable biotechnological approach to enhance plant anabolism, particularly the accumulation of bioactive metabolites that modulate the biological activities of plant-derived extracts. Despite the well-documented role of arbuscular mycorrhizal fungi in promoting secondary metabolite production, a comprehensive evaluation regarding the bioactivity of extracts from mycorrhizal plants remains lacking. This review consolidates 26 studies to identify trends in plant parts utilized, prevalent AMF inoculants, and assessed biological activities, including antifungal, antibacterial, antidiabetic, antiestrogenic, antityrosinase, cytotoxic, genotoxic, and larvicidal properties, as well as Sun Protection Factor enhancement. Considerations concerning the potential of mycorrhizal technology for generating plant raw material with outstanding biological activities, the relevance of establishing partnerships for research on this topic, and future assays to be carried out were addressed.

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Engineering Guide RNAs for CRISPR-Based Biosensors | acs

Engineering Guide RNAs for CRISPR-Based Biosensors | acs | RMH | Scoop.it

CRISPR-Cas systems, with their programmable nucleic acid-targeting capabilities, represent an ideal platform for constructing next-generation, highly sensitive biosensors. However, the clinical translation of these platforms is hindered by key limitations inherent to native single-guide RNAs (sgRNAs), including insufficient stability, potential immunogenicity, and off-target effects. To address these challenges, engineering sgRNAs has emerged as a central strategy to overcome such barriers and enhance overall biosensor performance. In this review, we provide a systematic overview of the field, beginning with the classification, molecular mechanisms, and structural features of representative CRISPR-Cas effector proteins to establish their foundational role as sensing elements. We then examine the specific limitations of native sgRNAs in biosensing applications. Building on this analysis, we highlight recent advances in sgRNA engineering strategies, which encompass three major approaches, including chemical modifications, structural remodeling, and modular functional integration. Furthermore, we review the integration of these engineered sgRNAs into advanced biosensor platforms, including microfluidic paper-based devices, centrifugal platforms, wearable patches, microneedles, and point-of-care testing (POCT) systems, and present a comparative table summarizing their performance in terms of detection signals, limits of detection, and other key metrics. Finally, we discuss persistent challenges such as the fine control of off-target effects, in vivo delivery bottlenecks, and system robustness in complex environments, and outline future directions toward amplification-free, multiplexed, and clinically translatable CRISPR-based biosensors. Overall, the engineering of sgRNAs offers a powerful means to systematically enhance the stability, specificity, and reliability of CRISPR-based biosensors, thereby accelerating their practical deployment in clinical diagnostics.

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Role of starvation survival response mechanisms on ribosome integrity, antibiotic tolerances, and virulence of Pseudomonas aeruginosa biofilms | npj

Bacterial biofilms contain physiologically diverse subpopulations of cells, including cells that are nutrient stressed or dormant. We determined how two dormancy pathways, ribosome hibernation and the stringent response, contribute to the survival and antibiotic tolerance of Pseudomonas aeruginosa biofilms. Analyses of whole biofilms and single cells showed that these pathways have differing effects on biofilm cell physiology. Ribosome hibernation, mediated by hibernation promoting factor (HPF), is essential for optimal survival and resuscitation of starved biofilm cells. In the absence of HPF, starved cells progressively lose ribosome integrity. However, loss of HPF does not increase the sensitivity of P. aeruginosa biofilm cells to ciprofloxacin or tobramycin. In contrast, the stringent response, mediated by RelA and SpoT, is not required for viability or ribosome integrity in starved biofilm cells, but does affect biofilm antibiotic tolerance. In a plant model of biofilm infection, disruption of either ribosome hibernation or the stringent response reduced bacterial virulence. The results show that ribosome hibernation preserves ribosomal integrity necessary for recovery from starvation and for pathogenesis, while the stringent response is required for growth arrest, antibiotic tolerance, and pathogenesis. These two ribosome-mediated pathways play distinct yet complementary roles in regulating dormancy and persistence of P. aeruginosa biofilms.

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PhageMind: generalized strain-level phage host range prediction via meta-learning | bft

PhageMind: generalized strain-level phage host range prediction via meta-learning | bft | RMH | Scoop.it

Bacteriophages are key regulators of bacterial populations and hold great promise for applications such as phage therapy, biocontrol, and industrial fermentation. The success of these applications depends on accurately determining phage host range, which is often specific at the strain level rather than the species level. However, existing computational approaches face major limitations: many rely on genus-specific features that do not generalize across taxa, while others require large amounts of training data that are unavailable for most bacterial lineages. These challenges create a critical need for methods that can accurately predict strain-level phage–host interactions across diverse bacterial genera, particularly under data-limited conditions.  We present PhageMind, a learning framework designed to address this challenge by enabling efficient transfer of knowledge across bacterial genera. PhageMind is trained to identify shared principles of phage–bacterium interactions from well-studied systems and to rapidly adapt these principles to new genera using only a small number of known interactions. To reflect the biological basis of infection, we represent phage–host relationships using a knowledge graph that explicitly incorporates phage tail fiber proteins and bacterial O-antigen biosynthesis gene clusters, and we use this representation to guide interaction prediction. Across four bacterial genera (Escherichia, Klebsiella, Vibrio, and Alteromonas), PhageMind achieves high prediction accuracy and shows strong adaptability to new lineages. In particular, in leave-one-genus-out evaluations, the model maintains robust performance when only limited reference data are available, demonstrating its potential as a scalable and practical tool for studying phage–host interactions across the global phageome.

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Self-generated hydrogel ejects bacterial cells for localized biofilm dispersion | Nmb

Self-generated hydrogel ejects bacterial cells for localized biofilm dispersion | Nmb | RMH | Scoop.it

Bacteria residing in biofilms are embedded in an extracellular matrix. Whereas biofilm formation is well studied, less is known about biofilm dispersion, although enzymatic extracellular matrix degradation is suspected to play a key role. Here we show that Bacillus subtilis biofilms can alternatively eject a specific cell type, locally and anisotropically, using mechanical forces arising from a self-generated hydrogel. Single-cell resolution imaging combined with mathematical modelling, and chemical and genetic perturbations, show that the production of the extracellular poly-γ-glutamic acid (γ-PGA) polymer is necessary to drive this cell ejection. Specifically, osmotic pressure from the γ-PGA hydrogel propels interior cells through the outer layers to break free from the biofilm. We demonstrate control over this process through γ-PGA modulation such that biofilm dispersion can be either inhibited or promoted. Forceful ejection driven by γ-PGA has so far only been described in marine organisms such as jellyfish. Our discovery of biofilm cell ejection via γ-PGA thus reveals not only a previously uncharacterized biofilm dispersion mechanism but also an unexpected mechanistic parallel to evolutionarily distant Cnidaria. Bacillus subtilis biofilms locally disperse by ejecting motile cells through osmotic pressure generated by their poly-γ-glutamic acid hydrogel, a mechanism resembling that through which Cnidaria eject nematocysts.

mhryu@live.com's insight:

suel gm, During biofilm development, cells inside the biofilm differentiate into two mutually exclusive cell types: motile cells and matrix cells. Motile cells are known to produce γ-PGA. Matrix cells are known to produce various ECM components that hold the biofilm together. 

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D-Amino Acids in Marine and Terrestrial Environments: Diversity and Uniformity of Their Microbial Catabolism | emb

D-Amino Acids in Marine and Terrestrial Environments: Diversity and Uniformity of Their Microbial Catabolism | emb | RMH | Scoop.it

D-amino acids (DAAs), once considered minor enantiomers, are now recognised as abundant and dynamic components of marine and terrestrial organic matter. While they do not participate in ribosomal protein synthesis, they play crucial roles in microbial physiology, particularly in bacterial cell wall structure. This review systematically synthesises the current understanding of DAA sources, distribution and fate, with a central focus on the microbial catabolic pathways that drive their recycling in marine and terrestrial environments. We show that, despite differences in DAA distribution and bioavailability between marine and terrestrial ecosystems, the core catabolic strategies adopted by bacteria—conversion to α-keto acids, L-amino acids (LAAs) or Gly—are largely conserved. We also evaluate limitations in current studies and major knowledge gaps, including the unclear role of marine fungi in DAA turnover and the relative lack of systematic studies on DAA-catabolising taxa and pathways in terrestrial microbial communities. This review highlights the ecological significance of microbial-mediated DAA recycling in marine and terrestrial environments, offering a better understanding of the global biogeochemical cycling of DAAs.

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Genomically integrated orthogonal translation system in Escherichia coli enables production of functional modified [NiFe]-hydrogenases | Mcf

Genomically integrated orthogonal translation system in Escherichia coli enables production of functional modified [NiFe]-hydrogenases | Mcf | RMH | Scoop.it

The functional diversification of O2-tolerant [NiFe]-hydrogenases using orthogonal translation systems (OTSs) offers a promising strategy for developing advanced biocatalysts and biohybrid energy platforms. However, plasmid-based OTSs frequently impose metabolic burdens and suffer from plasmid instability during fermentation, particularly when co-produced with complex metalloenzymes. To overcome these bioprocess limitations, we employed CRISPR/Cas9-mediated genome editing to integrate a psychrophilic pyrrolysyl-tRNA synthetase/tRNA pair into the E. coli BL21 genome. The resulting strain provided a plasmid-free orthogonal translation background that supported amber suppression-mediated expression of the regulatory [NiFe]-hydrogenase (RH) of Cupriavidus necator. Using this genomically integrated OTS, we achieved the production of a full-length, catalytically active RH variant. Our results demonstrate that chromosomal OTS is compatible with the efficient production and maturation of complex metalloenzymes. The present work lays the groundwork for the bio-orthogonal engineering of hydrogenases and related hybrid biocatalysts.

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M. burtonii pyrolysyl tRNA synthetase (MburPylRS) and M. alaskense tRNACUA under control of the constitutive promoters lpp and proK, respectively

a ncAA (Sac, a small "clickable" amino acid) at a specific spot on HoxB, near the end of that electron-relay chain, so that a synthetic redox catalyst or electrode to later be chemically attached there via click chemistry

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Shedding light on bacterial fitness in a tug-of-war with liquid crystal emulsions | Ncm

Shedding light on bacterial fitness in a tug-of-war with liquid crystal emulsions | Ncm | RMH | Scoop.it

Rapid and reliable quantification of bacterial dynamics at the cellular level is critical for pathogen sensing, live-dead bacterial assays, and monitoring of bacteria fitness and viability. Here, we demonstrate bacterial fitness quantification by capturing individual cells on topological defects of micro-scale liquid crystal emulsion droplets. The emulsion droplets are composed of phase-separated nematic liquid crystal and fluorocarbon components and exhibit an asymmetric mass distribution. A topological singularity in the director field of the liquid crystal phase localizes tailormade surfactants that tether a single bacterium per droplet. Active motion of the bacterium induces a tilt and azimuthal rotation of the droplet trap, which is counteracted by gravity acting on the droplet center of mass. By comparing the observed dynamics of a tethered bacterium’s stochastic movement to a computational model of bacterial motion on spherical surfaces that is based on the classical Ornstein-Uhlenbeck process, we quantify the fitness of bacteria subjected to starvation over several days. This pathogen fitness sensing concept, which relies on the scalable chemical design of single bacterial cell traps, a robust optical readout, and a theoretical understanding of bacterial dynamics on spherical surfaces, offers opportunities for rapid pathogen activity assessment, micro-biological sensing, and biologically powered micro-actuator systems. The ability to rapidly and accurately assess bacterial fitness is crucial for effective pathogen detection and monitoring. Here, authors develop a method using microscale liquid crystal emulsion droplets to capture individual bacteria, enabling real time quantification of their fitness through the analysis of droplet dynamics influenced by bacterial motion.

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1str, methods,

Individual bacteria are captured at the apex of a droplet, where the bacterial binding groups are located at the liquid crystal phase’s topological defect. The stochastic run-and-tumble motion of a bacterium anchored to a droplet tilts the droplet out of its equilibrium position, defined by the symmetry axis n of the droplet, until the force generated by the bacterium is balanced by the gravitational force acting on the droplet. The droplet tilt can be quantified by tracking its transmitted light intensity (A live bacterium is stuck to one spot on the droplet, but it keeps trying to swim in different directions. Since it can't actually go anywhere, that swimming effort instead pushes and spins the whole droplet. Gravity pulls the droplet back toward its resting position, so you get a constant push-pull)

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Systematic engineering and machine learning analysis of intrinsic terminators reveal crucial nucleotides directly upstream of the terminator hairpin | brvbe

Systematic engineering and machine learning analysis of intrinsic terminators reveal crucial nucleotides directly upstream of the terminator hairpin | brvbe | RMH | Scoop.it

Transcriptional termination efficiency is considered an important parameter for fine tuning bacterial gene expression. Still, the design principles that determine transcription termination efficiency remain poorly understood. In this study, we aimed to investigate the impact of the 3′ untranslated region (3′UTR) on gene expression in Escherichia coli and other bacteria. First, 3′UTR variant sequences were generated, with randomized 30 bp sequences inserted between the STOP-codon and an intrinsic terminator, consisting of a GC-rich hairpin and a downstream poly(U)-tail. Using three reporter genes, it was found that different 3′UTR sequences resulted in an up to five-fold difference in protein production, independent of the upstream coding sequence. The highest protein production was achieved when an adenosine was present directly upstream of the terminator hairpin. This was consolidated by systematic substitution of key nucleotides of the terminator and assessing their effect on mRNA and protein levels. Subsequently, we developed a predictive random forest machine learning model trained on the termination efficiency of different natural and synthetic terminator sequences, revealing an important role for the nucleotides directly upstream of the terminator hairpin. Altogether, this study showed that an additional adenosine nucleotide upstream of the terminator hairpin leads to improved protein production while reducing terminator read-through.

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oost, claassens

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