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mhryu@live.com
Today, 3:20 PM
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Extremophiles are microorganisms that thrive in environments previously thought to be uninhabitable, including extreme temperature, salinity, pH, pressure, and radiation. These organisms, found in Archaea, Bacteria, and Eukarya, exhibit distinct structural, metabolic, and genetic adaptations, such as enhanced enzyme stability, efficient DNA repair mechanisms, and robust stress-response systems that enable survival under extreme conditions. Understanding these adaptation mechanisms is key to engineering similar traits in mesophilic organisms. This review discusses the diversity of extremophiles and presents phylogenetic and comparative genomic insights which may provide insights into the origins and evolution of early life on Earth We highlight recent advances in CRISPR/Cas-based genome editing, genome-scale metabolic modeling (GEM), and synthetic biology that have expanded the use of extremophiles in sustainable industrial biotechnology. The exceptional stability and catalytic efficiency of extremozymes under harsh conditions underscore their potential in various biotechnological applications. Finally, we discuss the ecological significance of extremophiles in climate change mitigation and outline current challenges and future directions in extremophile research.
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mhryu@live.com
Today, 2:40 PM
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The advent of nano-technology has revolutionized approaches to identifying and combating bacterial infections. This review highlights the latest applications of nanoparticles (NPs) for bacterial detection and treatment, with a focus on their translational potential in clinical settings. We discuss advanced nanotechnology-enabled biosensing platforms that offer ultra-sensitive, rapid and precise diagnostics capabilities crucial for addressing antibiotic-resistant pathogens. In addition to detection, various nanoparticles demonstrate multiple antibacterial mechanisms and function as targeted drug-delivery vehicles. The review also examines current clinical trials involving nanoparticle-based therapeutics, underscoring their promise for overcoming antimicrobial resistance.
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mhryu@live.com
Today, 9:48 AM
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The “magic spot” nucleotides (MSNs) ppGpp and pppGpp constitute bacterial alarmones that orchestrate the conserved stringent response, a global regulatory mechanism enabling bacteria to adapt to nutrient deprivation and other environmental stresses. Current strategies to manipulate MSN levels rely mainly on genetic or environmental approaches, which are slow and lack temporal control. Chemical tools such as photocaged MSN analogues could provide such temporal control over MSN levels. However, the high negative charge of MSNs prevents spontaneous passage through the complex bacterial cell envelope. Here, we report the synthesis of photocaged, clickable, and isotope-labeled MSN analogues and their delivery into E. coli comparing different approaches. A cyclodextrin-based synthetic nucleotide transporter facilitated uptake. Upon 400 nm irradiation, these probes were photo-released inside living cells, where we tracked their conversion from pppGpp to ppGpp by capillary electrophoresis mass spectrometry and demonstrated their ability to alter growth in a (p)ppGpp0 mutant. These probes lay the foundation for spatially and temporally controlled studies of MSN function and of other highly negatively charged metabolites in vivo.
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mhryu@live.com
Today, 12:10 AM
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1,5-Pentanediol (1,5-PDO) is a high-value chemical with broad uses in polymer, cosmetic, and pharmaceutical industries. Although diverse biosynthetic pathways have been constructed, current recombinant strains typically rely on plasmid-based overexpression, which necessitates antibiotics and hinders industrial-scale production. We developed a robust, plasmid-free E. coli platform for de novo 1,5-PDO synthesis by integrating pathway genes (davB, davA, gabT, yahK, car, sfp and yqhD) into the chromosome of a lysine-hyperproducing strain via CRISPR/Cas9. Screening of carboxylic acid reductases identified Nocardia iowensis CAR-Ni as the most effective, yielding a base strain (D13) that produced 0.672 g/L 1,5-PDO. Integrated analysis confirmed the alcohol dehydrogenase (ADH)-mediated reduction of 5-hydroxypentanal (5-HP) as an underappreciated bottleneck. We subsequently screened ten endogenous ADHs and selected YjgB for computational optimization. Docking-guided saturation mutagenesis at position E205 yielded the variant YjgB(E205C), which exhibited a 3.34-fold increase in in vitro activity, reduced 5-HP accumulation, and elevated the titer to 0.935 g/L. Enhancing NADPH supply by integrating pntAB further raised the shake-flask titer to 1.5 g/L. In a 5-L fed-batch bioreactor, the final strain (D91) achieved 12.1 g/L 1,5-PDO (yield of 0.225 mol/mol glucose) without antibiotics or inducers. To our knowledge, this is the highest reported 1,5-PDO titer in E. coli. This study establishes a scalable, sustainable biosynthetic platform through synergistic metabolic engineering and computational enzyme optimization.
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February 26, 10:45 PM
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Experimental evolution is a powerful method that has been instrumental for revealing core mechanisms of adaptation and coevolution. It has mostly been used in very simple settings of one or two species. Yet, it is now increasingly being employed in more complex community settings that include indirect effects, higher-order interactions, and multidimensional selection typical of natural communities. Here we synthesize the emerging field of experimental evolution in communities and show how community context reshapes selection and evolutionary trajectories, beyond what single-species or pairwise designs predict. We conducted a systematic literature survey targeting multi-species, multi-generation evolution, identifying 100 such studies with the number increasing recently. Despite this progress, most experiments are biased toward microbial systems and competitive interactions, leaving major gaps for predicting evolution in realistic communities. We discuss community ecology concepts in the light of experimental evolution, together with designs that address these concepts. We emphasize three main research areas: indirect and higher-order interactions that make selection multidimensional, eco-evolutionary feedbacks linking trait change to community dynamics, and genetic constraints that shape responses across interaction networks. We then discuss routes to increase ecological realism with field experiments and conclude by outlining key research fronts for experimental evolution in communities.
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mhryu@live.com
February 26, 4:40 PM
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Biosensor-assisted growth-coupled screening facilitates the directed evolution of enzymes. However, antibiotic resistance-dependent screening tools generally suffer from declining selection pressure. To overcome this limitation, we developed a toxin-antitoxin-based high-throughput screening platform (TASP) for engineering d-allulose 3-epimerase (DAE), driven by a redesigned d-allulose-responsive biosensor (DB). Engineering the pPsiA promoter expanded its dynamic range to 150 mM d-allulose and enhanced signal-to-noise ratio by 14.2-fold. The TASP incorporates the toxin-antitoxin (AtaT-AtaR) as a sustainable and cell-autonomous selection pressure, where mCherry is used as a reporter gene. This design precisely links DAE catalytic activity to cell growth phenotypes, enabling both visul monitoring and quantitative analysis to rapidly identify variants. Using TASP, we identified the mutant M4–2 (W14C/G67A/L151Y/F245 K), which exhibits a 5.2-fold increase in catalytic activity and a 3.5-fold increase in half-life at 60 °C. This work establishes a reliable platform for high-throughput screening of DAE variants and advances the development of growth-coupled selection strategies.
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mhryu@live.com
February 26, 4:31 PM
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Oxford Nanopore technology (ONT) enables rapid, portable pathogen identification and detection of antimicrobial resistance (AMR). Still, the reliability of downstream genomic analyses is highly dependent on DNA extraction quality, particularly in resource-limited settings. This study comparatively evaluated four portable bacterial DNA extraction protocols, derived from three commercial kits, to determine their impact on nanopore sequencing performance, bioinformatics workflow completion, and field deployability. Six Gram-negative bacterial isolates (Escherichia coli, n= 4; Pseudomonas sp., n= 1; and Salmonella sp., n= 1) were processed using four extraction protocols: SwiftX DNA, SwiftX DNA with proteinase K (ProtK), SwiftX ParaBact, and NucleoSpin Microbial. Twenty-four DNA extracts (6 isolates x 4 protocols) were sequenced on a single multiplexed MinION R10.4.1 flow cell. Sequencing data were analysed using validated Galaxy-based generic and species-specific pipelines, with workflow completion defined as successful progression through quality control, assembly, virulence, plasmid and AMR detection modules. DNA purity varied substantially by extraction protocol and was strongly associated with workflow success. NucleoSpin Microbial achieved 100% workflow completion, SwiftX ParaBact achieved 83%, while both SwiftX DNA-based protocols failed to complete full workflows. Higher A260/A280 ratios were strongly correlated with successful workflow completion (Spearman’s ρ = 0.767, p < 0.0001). Importantly, key AMR genes required to classify isolates as multidrug resistant were consistently detected using both NucleoSpin Microbial and SwiftX ParaBact extractions. However, NucleoSpin Microbial assemblies showed significantly higher contiguity and enabled broader and more complete detection of virulence factors, pathogenicity islands, plasmid replicons, and accessory AMR genes, reflecting enhanced genomic resolution.
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mhryu@live.com
February 26, 4:16 PM
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Genetically encoded biosensors represent cutting-edge biosensors due to their capabilities in real-time monitoring and precise control in living cells. However, the development of eukaryotic genetically encoded biosensors for new analytes is constrained by the shortage of signal–receptor pairs. Bacterial biosensors have been transferred to eukaryotes to expand the signal detection space, which has achieved remarkable success. However, due to the significant differences between eukaryotic and prokaryotic gene expression systems, optimizing bacterial biosensors has proven challenging. Successful cases indicate that developing orthogonal signal–receptor pairs directly from eukaryotic systems may offer a viable solution. Indeed, the potential of filamentous fungi—a highly diverse group of organisms that share conserved as well as specific signaling and metabolic pathways with yeast and mammalian cells—has been largely overlooked in biosensor development. In this review, we systematically examine biosensing systems in filamentous fungi, summarize their signal recognition receptors, signal transduction pathways, responsive transcription factors, and provide an overview of the biosensors and synthetic tools developed from them. Finally, we highlight the promise and challenges of biosensor development from filamentous fungi and discuss their potential applications.
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February 26, 3:46 PM
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RNA pseudouridylation is one of the most prevalent post-transcriptional modifications, occurring universally across all organisms. Although pseudouridines have been extensively studied in bacterial tRNAs and rRNAs, their presence and role in bacterial mRNA remain poorly characterized. Here, we used a bisulfite-based deep sequencing approach to provide a comprehensive and quantitative measurement of bacterial pseudouridines using E. coli, to provide proof of concept. We identified 1,954 high-confidence sites in 1,331 transcripts, which is 29 times above previous estimates and representing almost 30% of the transcriptome. Furthermore, pseudouridines were significantly associated with mRNA stability and enriched in transcripts associated with secondary metabolite production and adaptation to diverse environments. Finally, we mapped pseudouridines in oral microbiome samples of human subjects, demonstrating the broad applicability of our approach in complex microbiomes. This way, we observe that, although uridines are required for modification, mRNAs from GC-rich bacteria harbored more pseudouridine sites than AT-rich genomes in our dataset. Altogether, our work highlights the advantages of mapping bacterial pseudouridines and provides a tool to study posttranscription regulation in microbial communities. Pseudouridines are RNA modifications occurring in all organisms. Here, Sharma et al. identify and quantify pseudouridines in E. coli bacteria, where this modification is associated with mRNA stability, and map pseudouridines in human oral microbiome samples.
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mhryu@live.com
February 26, 3:34 PM
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The rise of antimicrobial-resistant pathogens has outpaced the traditional methods of drug discovery and development, emphasizing a need for new and innovative approaches to identifying novel antibiotics. Artificial intelligence (AI) poses new opportunities to overcome the challenges in traditional drug discovery by accelerating the identification, design, and optimization of bioactive small molecules and antimicrobial peptides. AI-driven genome mining allows for the identification and prioritization of biosynthetic gene clusters, while advanced AI models facilitate molecular property prediction, predicted binding interactions, and novel structure design. This review explores the advancements that AI has enabled in antimicrobial discovery and design, as well as its current limitations.
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mhryu@live.com
February 26, 3:16 PM
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In natural environments, bacteria often encounter low concentrations of nutrient mixtures that are continuously replenished by physical processes such as fluid flow. Studying bacterial physiology under such conditions is experimentally challenging because it is difficult to maintain steady, low nutrient concentrations with rapid renewal. Most studies on nutrient limitation have used approaches such as the chemostat, which rely on long renewal times to sustain low concentrations. We developed a Millifluidic Continuous Culture Device (MCCD), inspired by microfluidics, that enables bacterial cultivation in nutrient mixtures at low micromolar concentrations with rapid renewal driven by fluid flow. Unlike microfluidic systems, the MCCD retains sufficient culture volume to support batch-scale ‘omic analyses. Using the MCCD, we cultured E. coli in a mixture of amino acids and nucleobases at three concentration ranges spanning a fivefold difference in growth rates. Surprisingly, at the lowest concentration range, cells exhibited proteomic signatures of iron limitation despite equal total ferrous iron across conditions. Uptake experiments with labeled iron–histidine and iron–cysteine complexes confirmed that amino acids facilitated ferrous iron acquisition. Under continuous flow, siderophores were washed out, rendering this pathway ineffective and revealing a previously unrecognized mechanism of iron acquisition via soluble ferrous iron–amino acid complexes. These findings highlight the importance of studying bacterial physiology at low nutrient concentrations and also suggest a broader role for other organic substrates capable of complexing iron as potential iron sources in environments with rapid renewal.
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mhryu@live.com
February 26, 12:55 PM
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Hyperspectral imaging (HSI) is an advanced sensing modality that captures spatial and spectral information simultaneously, enabling non-invasive and label-free characterization of material, chemical and biological properties. This Primer overviews HSI, with an emphasis on the imaging workflow and data processing pipeline. We introduce the essential physical principles and sensor architectures, using Earth observation HSI systems as a representative example. Key steps in data acquisition, calibration and correction that determine data structure and quality are discussed. We summarize common hyperspectral data forms and highlight core analytical techniques, including dimensionality reduction, classification and spectral unmixing, together with emerging artificial intelligence-based methods that increasingly influence current HSI research. Six representative application fields are briefly surveyed to illustrate how HSI enables sub-visual feature extraction for quantitative interpretation and decision-making. We also discuss persistent challenges, including hardware trade-offs, acquisition variability and high-dimensional complexity alongside promising advances such as computational imaging, physics-guided modelling, cross-modal fusion and scalable learning frameworks. Best practices for dataset sharing, reproducibility and metadata documentation to support transparent research are included. Scalable, real-time and embedded HSI, enabled by sensor miniaturization and artificial intelligence, will push HSI into a cross-disciplinary platform for transformative scientific and societal impact. This Primer introduces hyperspectral imaging (HSI) through a concise, imaging-centric perspective, linking sensor platforms, data types and representative datasets across application domains. It highlights how platform characteristics shape data properties and downstream analysis, providing a unified reference for understanding and comparing HSI systems and data.
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mhryu@live.com
February 26, 12:48 PM
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In vitro reconstitution of protein systems—e.g., metabolic pathways, genetic circuits or biosensors—often requires optimization to enhance their activity. Combinatorial DNA libraries that simultaneously target multiple genes allow for a holistic optimization strategy by studying the interplay between the systems′ components, which may reveal DNA variants that would be hidden when testing each element in isolation. Here, we screen large populations of synthetic vesicles that express combinatorial DNA variants of a DNA self-replicator or a phospholipid synthesis pathway. We simultaneously vary the strengths of multiple RBSs or synonymously mutate the first codons of multiple genes to explore the effects of the protein translation rates directly on the functionality of the two core synthetic cell modules. We isolated high performers through DNA self-selection or functional screening by fluorescence-activated cell sorting. Long-read sequencing of the fittest variants informed on the optimal RBS strengths and base substitutions in the first codons and indicated which genes were most impactful in regulating the functionality of the protein systems. Single-mutation data were used to predict the fitness of combinatorial variants, which was compared with the experimental fitness observed. The theoretical fitness of combinatorial variants was extremely predictive for the two-gene library of the DNA replicator but less for the larger pathway library. Altogether, our approach exemplifies how combinatorial testing can be expanded from single proteins to multiprotein systems, which can in the future be extended to the evolutionary engineering of even larger genetic and metabolic networks, and eventually an entire artificial cell.
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mhryu@live.com
Today, 3:18 PM
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Both fungi and bacteria contribute to the efficiency of activated sludge processes. However, fungal degradability has historically been overlooked in the anaerobic fermentation of waste-activated sludge (WAS). This study investigated the role of an enriched microbial consortium of degrading fungi (MCDF) in WAS fermentation. MCDF was initially enriched using a mixture of WAS and two mesophilic anaerobic sludges with chitin as the substrate. Fungal diversity and key cell wall polysaccharides, including chitin, mannan, and glucans, were identified in WAS. The addition of enriched MCDF to WAS significantly increased methane production by 35% and disrupted the floc structure through degradation of native fungi. The enriched MCDF also utilized fungal polysaccharides from four fungal species (Candida albicans, Trichosporon asahii, Geotrichum sp., and Magnusiomyces capitatus) and facilitated the release of intracellular organics. Proteinophilum and Petrimonas were identified as the main producers of chitinase (EC 3.2.1.14). Additional microbial producers were identified for mannanase (EC 3.2.1.78), β−1,4-glucanase (EC 3.2.1.4), and β−1,3-glucanase (EC 3.2.1.6). The relative activities of these four hydrolases in WAS were only 0.01%–12.3% of those in enriched MCDF. These results highlight the multifunctional potential of MCDF enrichment in WAS digestion, including degradation of fungal cell wall polysaccharides, release of intracellular fungal organics, and hydrolysis of bacterial extracellular organics. Overall, this study demonstrates that the destruction of native fungi in WAS provides a promising approach to enhance methane production and anaerobic digestion efficiency in wastewater treatment plants.
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mhryu@live.com
Today, 2:25 PM
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Listeriosis is a foodborne infection caused by Listeria monocytogenes that causes febrile gastroenteritis and central nervous system infections and that can often lead to fatality. Upon consumption of contaminated food, Listeria is able to survive a number of gastrointestinal stressors, including competition with the host microbiota. The emergence of antibiotic-resistant clones of L. monocytogenes, together with the side effects of antibiotic treatment, highlights the need for alternatives or additives for its treatment and prevention. Saccharomyces boulardii is a probiotic yeast that is often used alongside antibiotics to minimize side effects since it is not affected by them as a result of its eukaryotic nature. Furthermore, it can be engineered to produce a wide range of molecules. We previously engineered Saccharomyces cerevisiae through CRISPR-Cas9 integration to produce Ply511, a bacteriophage endolysin active against L. monocytogenes, showing the potential of engineered yeast to produce endolysins for biocontrol. In this study, we extended this approach to the probiotic yeast S. boulardii and directly compared the two yeasts as secretion hosts for Ply511. Using a simulated human gastrointestinal environment, we evaluated their ability to retain endolysin activity and reduce L. monocytogenes levels. We then tested the cell extracts from both yeasts in a bacterial consortium termed SImplified HUman intestinal MIcrobiota (SIHUMI), confirming a specificity for Listeria. Finally, we evaluated their activity in a simulated intestinal fermentation using fecal samples from human donors. Overall, this study demonstrates the potential of delivering endolysins to the gut via engineered probiotic S. boulardii. Key points CRISPR-Cas9-engineered S. boulardii and S. cerevisiae were compared, both allowing the expression and activity of endolysin Ply511 against L. monocytogenes. Endolysin Ply511 retained its activity against L. monocytogenes in simulated gastrointestinal digestion and was specific against Listeria in a bacterial consortium termed SImplified HUman intestinal MIcrobiota (SIHUMI). Using fecal samples from human donors, the anti-Listeria effect was reduced potentially due to the lower metabolic activity of S. boulardii and the higher competition with the intestinal microbiome. Graphical Abstract
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mhryu@live.com
Today, 9:34 AM
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Microbial synthesis of chemicals still faces low production due to the complicated metabolic networks, which generally cannot be tackled by rational engineering strategies. In this study, we report on a workflow, biosensor-guided indexing of genome evolution (BRIDGE), to obtain marker-free engineered strains with improved chemical production. We adopt the BRIDGE system to achieve high-level protocatechuic acid (PCA) production in Pseudomonas putida, reaching 4.67 g l−1 in shake flasks. Transcriptomics analysis reveals a synergy between metabolic pathway activation and the secretion system, allowing PCA overproduction. Furthermore, we demonstrate that the engineered P. putida can serve as a platform for de novo synthesis of other chemicals with high titers, achieving 2.97 g l−1 cis,cis-muconate in shake flasks. Since the BRIDGE system gives marker-free engineered strains, it would greatly favor downstream industrial applications. Considering the great variety of available biosensors, we envision that our BRIDGE approach will accelerate other microbial synthesis processes with enhanced productivity.
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mhryu@live.com
Today, 12:07 AM
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Bio-surfactants produced by microorganisms play essential roles in ecosystem function and hold significance promise for biotechnological applications. However, their diversity and distribution remain poorly depicted due to the limitations of culture-based approaches. In this study, we conducted a large-scale genomic data mining of 142,135 microbial genomes of putative biosurfactant-producing taxa, spanning 21 distinct ecosystems, to systematically profile gene association with 10 major biosurfactant classes. Using a list of 18 key functional genes, we mapped their taxonomic and ecological distribution and analyzed patterns of gene co-occurrence. We found that rhamnolipid biosynthesis genes are nearly ubiquitous across microbial lineages, reflecting their fundamental role in microbial adaptation. In contrast, emulsan and serrawettin pathways are more restricted to plant-associated and fungal ecosystems. The highest diversity of biosurfactant-related genes was found in genomes recovered from nutrient-rich habitats, including plant-associated, algal, and wastewater ecosystems. Co-occurrence network analysis revealed two distinct organizational strategies: a rare, conserved core cluster of genes associated with fengycin, surfactin, iturin lichenysin and plipastatin production, and a widespread, modular periphery linked to rhamnolipid, emulsan, and serrawettin W1 pathways, that are likely driven by the need to adapt to environmental complexity. Notably, we identified previously unreported genomes with biosurfactant production potential, significantly expanding the known biodiversity and ecological range of potential producers. Our findings establish biosurfactant production as a key microbial trait shaped by habitat, with broad implications for microbial ecology, ecosystem monitoring and sustainable biotechnology. This work provides comprehensive genomic resource for biosurfactant research, laying the foundation for targeted bioprospecting and integrative functional studies.
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February 26, 5:18 PM
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Ensuring information flow (heredity) and metabolic processes (catalysis) are two important prerequisites for early evolution. The widely accepted “RNA world” theory proposes that ancient RNAs ensured both heredity and catalysis during the transition from prebiotic to biotic evolution. However, alternative hypothetical molecules and processes have also been proposed, suggesting that catalytic peptides may have existed before polynucleotides, and that their sequences were later reverse translated into genes. Our objective was to experimentally address these alternative theories by asking whether the steps required for the hypothetical conversion of peptide sequences into DNA could be catalyzed by the existing molecular kit. The reactions we tested comprise i) step-wise degradation of peptides by a processive amino peptidase, sequentially releasing amino acids, ii) matching the identity of released amino acids to codons by aptazymes (RNA adapters that recognize amino acids and self-cleave and release specific codon triplets in response), and iii) ligating codon triplets into longer RNAs that can be reverse-transcribed into DNA. In a hypothetical processive system based on these reactions, the resulting DNA sequence would match the sequence of amino acids in the starting peptide. Our results suggest that all these steps can be catalyzed, and therefore the possibility of reverse translation occurring at some point in early evolution should not be disregarded.
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February 26, 4:36 PM
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RNA interference (RNAi)-based molecular biopesticides represent a transformative approach to sustainable crop protection. By harnessing a natural gene silencing mechanism, these next-generation pesticides offer unparalleled species specificity, potentially overcoming the limitations of broad-spectrum chemicals. This review systematically outlines the research and development framework for RNA biopesticides. We explore the core processes of target gene discovery, RNA design with the use of computational tools, and scalable production methods. A significant focus is placed on delivery strategies, including nanocarriers and carrier-free systems. Furthermore, we critically discuss the biosafety considerations and ecological impacts of deploying RNAi agents in the environment. This review synthesizes how RNA biopesticides, inspired by nature and refined by scientific precision, can be integrated into agricultural ecosystems for harmonious and effective crop protection.
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mhryu@live.com
February 26, 4:27 PM
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Diatoms are microscopic marine algae that are critical for global primary production, carbon sequestration, and fisheries productivity. However, select diatoms may form harmful algal blooms, which threaten marine ecosystems and the fisheries they sustain. Rapidly identifying harmful blooms is necessary to effectively manage marine resources, yet current identification methods are limited by expensive and labor-intensive in situ point sampling. Hyperspectral remote sensing enables scalable monitoring, but its ability to resolve taxonomic shifts within phytoplankton groups (e.g. diatoms) is largely unknown. To investigate this uncertainty, we cultured four dominant diatom genera from the California Current upwelling system, including this systems' most abundant harmful algae, Pseudo-nitzschia. The hyperspectral absorption and backscatter of these taxa were measured and used to model spectral reflectances that remote sensing platforms (satellites/drones) might detect. Differences between fingerprints of these taxa were quantified using vector-based and statistical analyses. Mean spectral differences of 48% were observed between the most dominant diatom, Thalassiosira, and the most toxic diatom, Pseudo-nitzschia. Differences of approximately 30% were found between Pseudo-nitzschia and the second and third most abundant diatoms, Chaetoceros and Asterionellopsis. Successful identification of Pseudo-nitzschia's reflectance fingerprint was driven by the presence of a unique feature around 560 nm. The distinct spectral fingerprint of Pseudo-nitzschia indicates that it can be distinguished from benign diatom blooms using hyperspectral remote sensing platforms.
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mhryu@live.com
February 26, 4:12 PM
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Phages employ sophisticated transcriptional regulatory networks to optimize replication. Recently, Silverman et al. used RIL-seq (RNA interaction by ligation and sequencing) to reveal an additional layer of regulation and uncovered the Hfq-mediated posttranscriptional regulon of the model phage lambda.
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mhryu@live.com
February 26, 3:39 PM
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Accurate characterization of multi-state protein conformations is crucial for understanding their functional mechanisms and advancing targeted therapies. Extracting coevolutionary constraints from homologous sequences helps reveal protein structure and function, which can be automatically captured by MSA Transformer leveraging attention mechanisms. Making use of the multi-conformational coevolutionary signals captured by MSA Transformer, we introduce in this study EvoSplit to disentangle coevolutionary signals associated with distinct conformations to guide protein structure predictions. EvoSplit outperforms AF-Cluster on 85 fold-switching proteins and successfully models the conformations of proteins beyond AlphaFold2’s training set. We then identify 54 candidates with potential conformational diversity for cancer-related human proteins. Notably, for five GTPases, EvoSplit consistently predicts two conformations, one of which has not been previously reported. As an important example, the protein–protein interaction analysis provides new insights into novel HRAS function-associated conformations. Furthermore, the validity of these newly identified conformations is examined by evolutionary analysis and extensive molecular dynamics simulations. Understanding multi-state protein conformations is essential for elucidating their functions and developing targeted therapies. Here, the authors introduce EvoSplit, leveraging MSA Transformer to disentangle coevolutionary signals associated with distinct conformations, outperforming AF-Cluster in modeling fold-switching proteins and identifying new conformations of GTPases and HRAS.
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February 26, 3:33 PM
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Raman spectroscopy can be used to predict cellular physiology and proteome composition in E. coli.
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February 26, 2:21 PM
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In P. aeruginosa chronic infections heme is a primary source of the essential micronutrient iron. The cytoplasmic heme-binding protein, PhuS, regulates extracellular heme flux through its interaction with the iron-regulated heme oxygenase (HemO). Additionally, in its apo-state PhuS modulates iron homeostasis through transcriptional regulation of the prrF1,2 sRNA genes. These two functions are mutually exclusive and dependent on the conformational rearrangement of PhuS upon heme binding and coordination. Herein, we characterize a PhuS R25A variant that shows similar heme binding kinetics and transfer of heme to HemO as PhuS WT, while DNA-binding to the prrF1 promoter is completely lost, successfully uncoupling the two functions. HDX-MS analysis revealed an overall decrease in conformational dynamics of the apo- and holo-PhuS R25A compared to their WT PhuS counterparts, demonstrating the importance of conformational flexibility for DNA-binding. qRT-PCR and Northern blot analysis comparing the phuSR25A allelic mutant strain to the PAO1 WT showed a significant decrease in PrrF and PrrH levels and revealed PhuS-dependent differences in regulation over PrrF1 and PrrF2, altering the relative ratio of these two sRNAs in a heme specific manner that is distinct from iron. By removing its DNA-binding function, we elucidated the direct effects of PhuS binding on PrrF expression, separate from its effects on heme transfer and utilization. The contrasting effects on gene expression of the tandem sRNAs PrrF1 and PrrF2 in iron and heme and the resulting distinct mRNA profiles may allow the bacteria a fitness advantage in establishing chronic infection.
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mhryu@live.com
February 26, 12:52 PM
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CRISPR-Cas12a has emerged as a versatile alternative to Cas9, offering distinct advantages, such as recognition of thymine-rich protospacer adjacent motifs, generation of staggered 5′ DNA breaks, simplified guide RNA architecture, and collateral (trans) single-stranded DNA cleavage. These features have enabled applications ranging from gene regulation to ultrasensitive nucleic-acid detection. However, Cas12a is typically activated immediately upon target engagement and may lack intrinsic mechanisms for restricting activity in time or space, which can increase off-target effects, systemic exposure, and loss of tissue specificity in certain contexts. Consequently, strategies that enable precise spatiotemporal control of Cas12a activity are increasingly important. Recent advances, including photocaged repeat-recognition sequence-based designs, split-crRNA architectures, chemically inducible systems, and kinetic optimization approaches, provide effective means to modulate Cas12a activation with improved precision. In diagnostic settings, temporal gating enhances signal fidelity by reducing background and false-positive readouts, while in therapeutic applications, controlled activation may enable tissue-restricted editing and safer, reversible gene regulation. This review summarizes current strategies for programmable spatiotemporal control of Cas12a, integrating mechanistic insights with emerging translational considerations, and outlines remaining challenges and opportunities for advancing safe and precise genome engineering.
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bacterial luciferase must associate cotranslationally to form the native αβ heterodimer; without cotranslational assembly, off-pathway ββ homodimers form (41). More recently, Günter Kramer, Bernd Bukau, and their coworkers (106) tested the impact of gene proximity on successful luciferase assembly by placing the α- and β-luciferase subunits either close together or far apart from one another on the bacterial chromosome.