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August 27, 9:53 AM
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Most of our current knowledge about yeast is based on the workhorse Saccharomyces cerevisiae. However, can this yeast represent the vast array of natural yeast life-forms? This review discusses significant recent advances in the study of non-Saccharomyces yeasts, also known as non-conventional yeasts (NCYs). We (a) review recent literature on bioprospecting methodologies and on population genomics that have expanded our understanding of NCY diversity, (b) highlight critical species with industrial applications, and (c) offer insights into how NCYs’ genetic diversity translates into phenotypic plasticity and adaptation to extreme environments. We assess the limitations that are delaying the widespread use of NCYs in biotechnology, including the need for ambitious bioprospecting efforts and robust genetic tools in the scaling up of NCY-based processes for industry. NCYs could offer novel sustainable solutions in the food, beverage, pharmaceutical, and bioenergy sectors and could open a new frontier of commercial opportunities.
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August 27, 12:45 AM
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The dynamics of bacterial population decline at antibiotic concentrations above the minimum inhibitory concentration (MIC) remain poorly characterized. This is because measuring colony-forming units (CFU), the standard assay to quantify inhibition, is too slow, labor-intensive, and costly, and can be unreliable at high drug concentrations. To offer an alternative for high antimicrobial concentrations, we measured the change in light intensity from bioluminescent Escherichia coli over time and compared it with the change in CFU counts as a proxy for population size. Currently, luminescence assays are commonly used below the MIC, but have not yet been evaluated extensively in the super-MIC range. For 12 of the 21 antimicrobials tested, luminescence- and CFU-based rates did not differ significantly. To investigate the source of the discrepancies observed for the remaining 9 antibiotics, we introduced a size-structured population model with a continuum of cell sizes to simulate the impact of filamentation on the light signal, and complemented the findings with microscopy imaging. Discrepancies between the two rates fell into two classes. First, because light intensity tracks biomass more closely than population size, luminescence can indicate a shallower population decline when bacteria filament. Second, CFU-based estimates can indicate a steeper population decline when antimicrobial treatment reduces the number of colonies formed per viable bacterium. This effect can result from changes in clustering behaviour, physiological changes that impair culturability, or antimicrobial carry-over. With these caveats addressed, bioluminescence offers an efficient, high-throughput alternative for quantifying bacterial dynamics at super-MIC concentrations, although its suitability depends on the chosen metric (biomass vs. cell number) and on whether the antimicrobial induces filamentation or affects culturability.
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August 27, 12:26 AM
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Pseudomonas aeruginosa and Klebsiella pneumoniae are Gram-negative opportunistic pathogens that frequently colonize the human body and are major causes of infection. These bacteria are often co-isolated in polymicrobial urinary tract and lung infections, the latter of which is associated with increased disease severity and worse clinical outcomes. Despite their overlapping niches and clinical relevance, little is known about how these two pathogens interact and how those interactions influence human health. Given the growing recognition that microbial interactions are key drivers of disease, we investigated how P. aeruginosa and K. pneumoniae influence one another. We discovered an antagonistic interaction in which P. aeruginosa restricts the growth of K. pneumoniae. This inhibition is driven by phenazine production in P. aeruginosa, specifically the secondary metabolites pyocyanin and pyorubin, which are both necessary and sufficient to suppress K. pneumoniae growth. Using a diverse set of clinical isolates, we found that this antagonism is strain dependent. Both the susceptibility of K. pneumoniae to phenazines and the ability of P. aeruginosa to restrict K. pneumoniae growth varies between strains. Moreover, the necessity of phenazine production is specific to the site of infection. Together, these findings demonstrate that strain background and environmental context are critical determinants of pathogen interactions. Our work underscores the importance of considering these variables when investigating how microbial interactions influence infection and disease outcomes.
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August 27, 12:10 AM
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Studying microbial community dynamics is fundamental to better understand ecosystem stability, resilience and environmental change. Community composition changes with the growth of individual members, yet current methods to estimate microbial growth in communities face substantial limitations. For example, genome sequence-based estimates of maximum growth rates may not reflect growth patterns in the natural environment well, and metagenomic in situ growth prediction requires the availability of reference genomes and shows limited accuracy for slow-growing bacteria. Gene expression data provide an information-rich readout of community activity that could reflect growth, however, cross-species comparisons in community settings remain challenging. An approach using expression signatures of universal, single-copy marker genes provides independence from reference genomes and may thereby enable comparability across species. Here, we present a transcriptomic, marker gene-based growth classifier that predicts the growth states of bacterial strains from different phyla cultivated in diverse conditions. We demonstrate its application in vivo in gnotobiotic mice carrying the same bacterial strains, and in a more complex synthetic community, where predicted growth states align with reported growth inhibition induced by systemic inflammatory response. This approach offers a new method for predicting bacterial growth states across species, with potential for broad application in the study of microbial growth dynamics at the whole community level.
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August 26, 10:40 PM
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Modern chemical manufacturing, on which human quality of life depends, is unsustainable; alternative production routes must be developed. Electrochemical and biological processes offer promise for upgrading waste streams, including recalcitrant carbon dioxide and plastic-derived wastes. However, the inherent heterogeneity and high energy requirements of upcycling the chemical endpoints of the “take-make-waste" economy remain challenging. Cupriavidus necator is an emergent catalyst for complex feedstock valorization because of its extreme metabolic flexibility, which allows it to utilize a wide array of substrates, and its ability to use carbon dioxide via the Calvin-Benson-Bassham cycle. C. necator natively oxidizes hydrogen to power carbon utilization, but its flexibility offers an as-yet unexplored opportunity to couple waste stream oxidation with carbon dioxide utilization instead, potentially enabling carbon conservative waste upcycling. Here, we uncover the constraints on carbon conservative chemical transformation using C. necator as a model. We systematically examine the carbon yield and thermodynamic feasibility of mixotrophic scenarios combining waste-derived carbon sources with hydrogen oxidation to power carbon reassimilation. Then, we evaluate carbon-carbon mixotrophic scenarios, with one carbon source providing electrons in place of hydrogen oxidation. We show that both hydrogen and ethylene glycol are feasible electron sources to drive carbon-neutral or carbon-negative mixotrophic upgrading of waste streams such as acetate or butyrate. In contrast, we find that carbon conservation is likely infeasible for most other waste-derived carbon sources. This work provides a roadmap to establishing novel C. necator strains capable of carbon efficient waste upcycling.
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August 26, 10:02 PM
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Cold seep ecosystems serve as critical hubs in marine carbon cycling through methane emissions and organic matter processing. While terrestrial lignin constitutes a major fraction of persistent organic carbon in cold seep sediments, its microbial transformation pathways in deep-sea cold seep environments remain unexplored. Here, we present the first comprehensive analysis of lignin distribution across sediment horizons at the Haima cold seep, coupled with a multi-omics investigation of microbial lignin metabolism. Laboratory enrichment of sediment communities employing lignin as the exclusive carbon substrate revealed substantial microbial community restructuring dominated by Burkholderiales, Pseudomonadales, and Rhizobiales lineages. Integrated omics resolved 2-tiered metabolic cascades: (a) enzymatic depolymerization via dyP-type peroxidases and LigEFG-mediated β-aryl ether cleavage, targeting syringyl and diarylpropane subunits; (b) funneling of aromatic intermediates through 4,5-/3,4-PDOG (protocatechuate dioxygenase) pathways into central carbon metabolism. Although direct methanogenesis was undetected, methylotrophic potential was evidenced through methane cycle gene expression patterns by lignin decomposers. Phylogenetic surveys further demonstrated the global prevalence of lignin decomposers across 12 major cold seep systems. These decomposers showed marked divergence in enzymatic repertoires compared to degraders from other ecosystems. Our findings establish 3 paradigm shifts: (a) The turnover rates of terrestrial organic carbon are likely underestimated in deep-sea ecosystems; (b) microbial consortia employ combinatorial enzymatic strategies distinct from terrestrial decomposition regimes; (c) methyl shunting from lignin breakdown primes methanogenic precursors, revealing cryptic linkages between refractory carbon cycling and greenhouse gas reservoirs.
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August 26, 4:32 PM
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Bacteria have several nucleotide second messengers, most of which act as global regulators to control a wide range of bacterial physiological processes. Studies usually focus on a single second messenger, and the mechanisms and physiological significance of the cross-regulation between different nucleotide second messengers are often unclear. Here, we show that Shewanella putrefaciens can form biofilms in both nutrient-rich and nutrient-poor media. While both are controlled by c-di-GMP, the regulatory models differ. Under low nutrient conditions, cross-regulation of cAMP-CRP and c-di-GMP occurs at the transcriptional and posttranslational levels, thereby controlling biofilm development. During the early stages of biofilm development, cAMP-CRP directly promotes the transcription of a PDE gene, lrbR, by LrbA. Additionally, cAMP-CRP recruits LrbR to BpfD to suppress early biofilm formation via LrbR-dependent local degradation of c-di-GMP. Finally, as intracellular LrbR levels decrease, cAMP-CRP-BpfD enables a rapid shift to biofilm development and supports biofilm maintenance. Under high nutrient conditions, this cross-regulation does not occur, resulting in a positive correlation between global c-di-GMP levels and biofilm biomass. The identification of distinct modes of biofilm regulation in different nutrients will provide a theoretical basis for future targeted control of biofilm formation in different nutrient environments.
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August 26, 3:00 PM
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As a key bacterial actin-like protein, MreB plays crucial roles in maintaining cell shape, regulating peptidoglycan synthesis, and coordinating chromosome segregation, making it a promising target for novel antibiotics. This review comprehensively explores MreB’s molecular architecture, its assembly into antiparallel protofilaments, and its pivotal roles in bacterial cell morphology and division. We also delve into how MreB interacts with membrane-associated proteins such as RodZ and MreC/D to coordinate cell wall synthesis and respond to environmental signals like ion gradients and temperature changes. Furthermore, we highlight the cooperation and functional divergence between MreB and FtsZ, underscoring the evolutionary adaptability of bacterial cytoskeletal structures. The structural and functional parallels between MreB and eukaryotic cytoskeletal proteins are also examined, offering new insights into the evolution of cytoskeletal systems. By integrating insights from structural biology, synthetic biology, and microbial ecology, this review aims to provide a deeper understanding of MreB’s role in bacterial biology, its dynamic responses to environmental cues, and its implications for therapeutic innovation. This comprehensive analysis not only enhances our knowledge of bacterial self-organization mechanisms but also paves the way for the development of innovative antimicrobial strategies to address the growing challenge of antibiotic resistance.
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August 26, 10:02 AM
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Transfer RNA (tRNA) plays a central role in translation. The simultaneous in vitro synthesis of minimal yet sufficient tRNA species (at least 21) poses a challenge for constructing a self-reproducible artificial cell. A key obstacle is the processing of the 5’ and 3’ ends, which requires a multi-step reaction in the natural cells. In this study, we develop a simplified processing method that allows simultaneous expression of all 21 tRNAs in a reconstituted transcription/translation system (PURE system). We test two methods for 5’-end processing (the leader and 5’-G variants methods) and two methods for 3’-end processing (the direct tRNA linkage and HDVR attachment methods). Finally, by combining the direct tRNA linkage and HDVR attachment methods (newly termed the tRNA array method), we succeed in simultaneously expressing all 21 tRNAs from a single polycistronic DNA template in the PURE system. The tRNA mixture produced by the tRNA array method supports a similar level of translation to the individually synthesized tRNA mixture for luciferase and GFP. This study represents a step toward the realization of self-reproducible artificial cells and also provides an easy method for preparing all tRNAs useful for genetic code engineering. tRNAs are essential for translating genetic information into proteins. Here, the authors develop a method to synthesize all 21 essential tRNAs from a single DNA in vitro, enabling protein production and providing a foundation for artificial cells and genetic code reprogramming.
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August 26, 9:58 AM
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Cell signaling and communication are fundamental to living cellular communities. Over the past two decades, there has been a continuous development of bottom-up engineered synthetic cells, which have become increasingly similar to their natural counterparts. However, we are only scratching the surface with the development of synthetic cellular communities and their integration into natural tissues. Here we review different intercellular communication mechanisms engineered for synthetic cells and classify them based on their resemblance to natural cell signaling mechanisms—autocrine, paracrine and juxtacrine. In particular, we highlight recent advances in molecular tools for intercellular communication strategies and discuss potential applications of engineering synthetic cellular communities and synthetic cell–natural cell communication. With further advances in this area, synthetic cellular communities will be powerful tools for understanding and manipulating cellular functions, thus unlocking potential applications in biosensing, cellular reprogramming and sustainability. Recent advances in engineering bottom-up synthetic cells have created powerful compartmentalized biochemical reactors with cell-like abilities. To push the boundaries of the collective capabilities of synthetic cells and unlock biomedical applications, biomimicry of signaling and communication is imperative. This Review highlights state-of-the-art communication mechanisms between synthetic cells and discusses potential applications.
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August 26, 9:38 AM
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Recent breakthroughs in protein structure prediction have led to a surge in high-quality 3D models, highlighting the need for efficient computational solutions. In our work, we examine the structural clusters from the AlphaFold Protein Structure Database (AFDB), a high-quality subset of ESMAtlas, and the Microbiome Immunity Project (MIP). We create a single cohesive low-dimensional representation of the resulting protein space. We show that, while each database occupies distinct regions, they collectively exhibit significant overlap in their functional profiles. High-level biological functions tend to cluster in particular regions, revealing a shared functional landscape despite the diverse sources of data. By creating a representation of protein structure space, localizing functional annotations within this space, and providing an open-access web-server for exploration, this work offers insights for future research concerning protein sequence-structure-function relationships, enabling biological questions to be asked about taxonomic assignments, environmental factors, or functional specificity. This approach is generalizable, thus enabling further discovery beyond findings presented here. Researchers mapped the protein structure landscape, revealing structural complementarity across databases and functional clustering in specific regions. Their web tool helps explore this space, unlocking new insights into protein roles, evolution, and diversity.
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August 26, 1:27 AM
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Microbial protein is a promising alternative to animal and plant proteins. Aspergillus niger, a generally recognized as safe (GRAS) microorganism, is frequently used for heterologous protein production, although its expression efficiency is constrained by multiple factors, including gene transcription, metabolic flux distribution, protein folding, and secretion pathways. However, constructing universal Aspergillus niger chassis cells for efficient protein production remains challenging due to the diverse properties of different proteins. With advancements in synthetic biology, numerous molecular biology tools and metabolic engineering strategies have been employed to address these issues. This article summarizes and discusses the latest progress in enhancing heterologous protein production from five dimensions: expression systems, secretion pathways, metabolic flux, intelligent fermentation, and systematic optimization through multi-omics integration. Additionally, it prospects the efficient and sustainable production of heterologous proteins by Aspergillus niger.
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August 26, 1:18 AM
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Endophytic bacteria, living symbiotically in plant tissues, have attracted great attention due to their antioxidant potential. These microorganisms are capable of producing bioactive compounds, including enzymes and secondary metabolites, which help reduce oxidative stress in plants and can be cultured in artificial media, opening up broad prospects for future applications. This article provides an overview of the antioxidant potential of plant endophytic bacteria, focusing on spectroscopic analytical techniques: 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) free radical neutralization, 2,2-diphenyl-1-picrylhydrazyl free radical neutralization (DPPH), ferric reducing-antioxidant power (FRAP) and total antioxidant capacity (TAC). These methods collectively highlight the strong antioxidant capacity of endophytic bacteria and underscore their role as a promising source of natural antioxidants for future biotechnological applications.
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August 27, 9:50 AM
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The human microbiome profoundly influences health and disease. Robust computational and statistical tools for identifying causal microbe-disease links are therefore critical to uncovering the mechanistic basis of these associations. Yet benchmarking such tools remains difficult: microbiome datasets are sparse, high-dimensional, and contain complex dependencies, and no gold-standard reference set exists. Realistic simulated data with embedded ground truth are essential for fair evaluation of analytical tools. Current simulators often impose strong assumptions, require hard-to-obtain auxiliary information, or fail to scale to large, high-dimensional datasets. We introduce DeepBioSim, a DEEP-learning framework for BIOlogical SIMulation of microbiome data. DeepBioSim uses variational autoencoders (VAEs) to generate realistic microbiome datasets by sampling directly from the latent distribution of metagenomic or metatranscriptomic count data.The approach is fast, accurate, and scalable, generating highly realistic synthetic microbiome datasets without extensive hyper-parameter tuning or phylogenetic input. Tests on human RNA-seq data confirm versatility of DeepBioSim, showing it can also reliably simulate single-organism omics profiles.
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August 27, 12:38 AM
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Hydrogenotrophic methanogens are of high environmental and biotechnological relevance, as they convert CO2 with H2 into CH4. Despite their common metabolism, variations among these methanogens likely exist. This study therefore determined the H2 thresholds and growth yields of nine different hydrogenotrophic methanogens. The H2 threshold, i.e. the H2 partial pressure at which H2 consumption halts, ranged over two orders of magnitude from 1.0 +/- 0.5 Pa for Methanobrevibacter arboriphilus to 120 +/- 10 Pa for Methanosarcina mazei. Growth yields ranged from 0.51 +/- 0.28 gDCW / mol CH4) for Methanococcus maripaludis to 5.28 +/- 1.25 gDCW / mol CH4. In addition, ATP gains, estimated from both the H2 threshold and growth yield, correlated reasonably well, suggesting that these variations are due to differences in energy conservation strategies. Our results fitted with the classification previously proposed by Thauer, dividing hydrogenotrophic methanogens into two distinct groups: methanogens using cytochromes for energy conservation had a high H2 threshold (> 20 Pa) and high growth yield (> 4.0 gDCW / (mol CH4), whereas all methanogens without cytochromes had a low H2 threshold (< 8 Pa) and low growth yield (< 1.7 gDCW / (mol CH4). Moreover, our H2 thresholds showed significant additional variations within both groups. Overall, this study found strong variations between hydrogenotrophic methanogens, which are important to understand their environmental prevalence and biotechnological applicability.
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August 27, 12:16 AM
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Enzyme promiscuity can be the starting point for the evolution of new enzymatic activities and pathways. Previously Cotton et al. (2020) identified underground isoleucine biosynthesis routes that can replace the canonical route in Escherichia coli, after they deleted the enzymes that catalyze the formation of its precursor 2-ketobutyrate. Using this strain and short-term evolution we identify a new pathway for isoleucine biosynthesis based on the promiscuous activity of the native enzyme acetohydroxyacid synthase II. We demonstrate that this enzyme catalyzes the previously unreported condensation of glyoxylate with pyruvate to generate 2-ketobutyrate in vivo. The gene encoding this enzyme, ilvG, is inactivated by a frameshift mutation in the laboratory model strain E. coli K-12 MG1655. Its evolutionary reactivation we report here points to a potential natural role in isoleucine biosynthesis in E. coli. Isoleucine biosynthesis proceeds with a further condensation step of 2-ketobutyrate with pyruvate, again catalyzed by AHAS, giving the proposed pathway the unusual property of recursivity. The discovered enzyme activity uses glyoxylate and pyruvate as direct central metabolic precursors for isoleucine biosynthesis instead of its canonical ‘indirect’ biosynthesis via the amino acid threonine. Unlike previously discovered underground isoleucine routes by Cotton et al., this route is more likely to play a role in natural isoleucine biosynthesis in E. coli due to the use of ubiquitous metabolites and its activity in aerobic conditions. The discovered route further expands the known metabolic space for isoleucine biosynthesis in E. coli and potentially other organisms, and could find applications in biotechnological isoleucine production.
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August 26, 10:56 PM
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Enzymes are essential biological catalysts that drive nearly all biochemical reactions. Understanding their efficiency and specificity involves studying enzyme kinetics, particularly the parameters kcat and Km. However, there is limited data linking these kinetic parameters with the three-dimensional (3D) structures of enzyme-substrate complexes. Since enzyme function is determined by its structure, such mapping enhances insight into structural basis of enzymatic function and supports applications in enzyme design, synthetic biology and metabolic engineering. To address this critical gap, this work presents SKiD (Structure-oriented Kinetics Dataset), a comprehensive, structured dataset integrating kcat and Km values with the corresponding 3D structural data. This is accomplished by integrating data from existing bioinformatics resources using automated programs to process the data and enhancing it with computational predictions. The erroneous data encountered during data integration is manually resolved. Metadata such as literature and assay conditions (e.g., pH and temperature) are preserved. The 3D coordinates of the modelled enzyme-substrate complexes are provided along with their UniProtKB identifier.
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August 26, 10:29 PM
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Axenic cultures are essential for studying microbial ecology, evolution, and genomics. Despite the importance of pure cultures, public culture collections are biased towards fast-growing copiotrophs, while many abundant aquatic prokaryotes remain uncultured due to uncharacterized growth requirements and oligotrophic lifestyles. Here, we applied high-throughput dilution-to-extinction cultivation using defined media that mimic natural conditions to samples from 14 Central European lakes, yielding 627 axenic strains. These cultures include 15 genera among the 30 most abundant freshwater bacteria identified via metagenomics, collectively representing up to 72% of genera detected in the original samples (average 40%) and are widespread in freshwater systems globally. Genome-sequenced strains are closely related to metagenome-assembled genomes (MAGs) from the same samples, many of which remain undescribed. We propose a classification of several novel families, genera, and species, including many slowly growing, genome-streamlined oligotrophs that are notoriously underrepresented in public repositories. Our large-scale initiative to cultivate the “uncultivated microbial majority” has yielded a valuable collection of abundant freshwater microbes, characterized by diverse metabolic pathways and lifestyles. This culture collection includes promising candidates for oligotrophic model organisms, suitable for a wide array of ecological studies aimed at advancing our ecological and functional understanding of dominant, yet previously uncultured, taxa. A large fraction of aquatic bacteria remains uncultured. Here, the authors cultivated 627 strains of abundant freshwater bacteria from 14 European lakes, thus generating a collection that includes many previously uncultured, oligotrophic bacteria that may serve as model organisms.
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August 26, 4:40 PM
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Uncovering phenotypic heterogeneity is fundamental to understanding processes such as development and stress responses. Due to the low mRNA abundance in single bacteria, determining biologically relevant heterogeneity remains a challenge. Using Microcolony-seq, a methodology that captures inherited heterogeneity by analyzing microcolonies originating from single bacterial cells, we uncover the ubiquitous ability of bacteria to maintain long-term inheritance of the host environment. Notably, we observe that growth to stationary phase erases the epigenetic inheritance. By leveraging this memory within each microcolony, Microcolony-seq combines bulk RNA sequencing (RNA-seq) with whole-genome sequencing and phenotypic assays to detect the distinct subpopulations and their fitness advantages. Applying this directly to infected human samples enables us to uncover a wealth of diverse inherited phenotypes. Our observations suggest that bacterial memory may be a widespread phenomenon in both Gram-negative and Gram-positive bacteria. Microcolony-seq provides potential targets for the rational design of therapies with the power to simultaneously target the coexisting subpopulations.
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August 26, 4:25 PM
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The fungal species Candida albicans and the bacterium Enterococcus faecalis are members of the human gut microbiome. To explore the range of interactions between these two species, we utilized dual RNA-sequencing to transcriptionally profile both C. albicans and E. faecalis during coculture (compared with monoculture controls) under two conditions: 1) an in vitro setting that mimics certain features of the gut environment and 2) a gnotobiotic mouse gut model. RNA-seq analysis revealed a large number of gene expression changes induced by one species in the presence of the other. More specifically, both species highly upregulate citrate-metabolizing genes during coculture: C. albicans upregulates CIT1 (citrate synthase) which produces citrate, while E. faecalis upregulates its cit operon, which breaks down citrate. In vitro analysis showed directly that citrate cross-feeding (production of citrate by C. albicans and breakdown by E. faecalis) enhances growth of E. faecalis. A main byproduct of citrate metabolism in E. faecalis is formate, a short chain fatty acid toxic to fungi. Our RNA profiling revealed that C. albicans upregulates three formate dehydrogenases (FDHs) during coculture; we show that the FDH genes confer a growth advantage to C. albicans when E. faecalis (or simply formate) is present. These findings reveal a metabolically driven cycle between C. albicans and E. faecalis in the mouse gut and in vitro, where cross-feeding of citrate and detoxification of formate facilitates the growth of both species when they are cultured together.
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August 26, 10:23 AM
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Endophytes are beneficial microorganisms that reside within plant tissues, playing a vital role in plant growth and stress tolerance. Endophytes successfully colonize host plants by employing a range of mechanisms, including cell wall modification, modulation of phytohormones, secretion of effector proteins, and the production of antioxidants. Certain endophytes can efficiently break down specific pollutants such as pesticides in the rhizosphere, phyllosphere, and endosphere. These microbes metabolize pesticides or alter their chemical structures using several enzymatic, genetic, or metabolic pathways. This review examines the underlying colonization mechanism of endophytes in plants, as well as their significance in pesticide degradation. The available data will raise many new questions about endophytic colonization dynamics, regulation of different genes involved in establishing endophytic associations and their role in pesticide degradation with a sustainable research perspective.
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August 26, 9:59 AM
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The increasing availability of hybrid sequencing datasets comprising both short and long reads, is radically transforming microbial genomics, with the prospect of obtaining routinely near-complete bacterial genome assemblies. However, the complete assemblies of mobile genetic elements, especially plasmids, still remain challenging. We introduce HyPlAs, an assembly pipeline specifically designed to assemble plasmids from hybrid bacterial sequencing datasets. HyPlAs main novelty is to incorporate the use of a prior classification of short-read contigs as chromosomal or plasmidic. We evaluate HyPlAs on a large set of bacterial samples and demonstrate that it outperforms its competitor Plassembler. Availability. HyPlAs is freely available at https://github.com/cchauve/HyPlAs.
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August 26, 9:44 AM
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Post-translational modifications (PTMs) are critical regulators of protein function, and their disruption is a key mechanism by which missense variants contribute to disease. Accurate PTM site prediction using deep learning can help identify PTM-altering variants, but progress has been limited by the lack of large, high-quality training datasets. Here, we introduce PTMAtlas, a curated compendium of 397,524 PTM sites generated through systematic reprocessing of 241 public mass-spectrometry datasets, and DeepMVP, a deep learning framework trained on PTMAtlas to predict PTM sites for phosphorylation, acetylation, methylation, sumoylation, ubiquitination and N-glycosylation. DeepMVP substantially outperforms existing tools across all six PTM types. Its application to predicting PTM-altering missense variants shows strong concordance with experimental results, validated using literature-curated variants and cancer proteogenomic datasets. Together, PTMAtlas and DeepMVP provide a robust platform for PTM research and a scalable framework for assessing the functional consequences of coding variants through the lens of PTMs. DeepMVP is a deep learning framework for predicting PTM sites and variant-induced alterations across six modification types, including phosphorylation, acetylation, methylation, sumoylation, ubiquitination and N-glycosylation.
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August 26, 1:33 AM
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The integration of biological functions into a single operating system is considered a major challenge in the construction of a synthetic cell. We present autocatalytic selection (ACS) of gene functions as a driver for integrating biological modules in vitro. A gene of interest (GOI) is introduced into a minimal DNA self-replicator based on the φ29 replication machinery and the function of the GOI is linked to transcription, translation or DNA replication through a positive feedback loop. As the encoded function eventually promotes DNA self-replication, the gene variants with greater activity are selected. Using different coupling mechanisms, we demonstrate ACS of three functions: transcription, synthesis of a deoxynucleoside triphosphate for DNA replication, and β-galactosidase activity. The latter example illustrates how a function that is unrelated to the Central Dogma can be selected. This work paves the way for ACS-driven Darwinian evolution of virtually any biomolecule in vitro, streamlining the construction of increasingly complex synthetic cells as well as the engineering of biotechnologically relevant enzymes.
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August 26, 1:26 AM
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Aspergillus niger has become one of the most important hosts for food enzyme production due to its unique food safety characteristics and excellent protein secretion systems. A series of food enzymes such as glucoamylase have been commercially produced by A. niger strains, making this species a suitable platform for the engineered of strains with improved enzyme production. However, difficulties in genetic manipulations and shortage of expression strategies limit the progress in this regard. Moreover, several mycotoxins have recently been detected in some A. niger strains, which raises the necessity for a regulatory approval process for food enzyme production. With robust strains, processing engineering strategies are also needed for producing the enzymes on a large scale, which is also challenging for A. niger, since its culture is aerobic, and non-Newtonian fluid properties are developed during submerged culture, making mixing and aeration very energy-intensive. In this article, the progress and challenges of developing A. niger for the production of food enzymes are reviewed, including its genetic manipulations, strategies for more efficient production of food enzymes, and elimination of mycotoxins for product safety.
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