Systems Biology
ALLTogether recommendations for biobanking samples from patients with acute lymphoblastic leukaemia: a modified Delphi study
Br J Cancer. 2025 Feb 22. doi: 10.1038/s41416-025-02958-x. Online ahead of print.
ABSTRACT
Acute lymphoblastic leukaemia (ALL) is a rare and heterogeneous disease. The ALLTogether consortium has implemented a treatment protocol to improve outcome and reduce treatment-related toxicity across much of Europe. The consortium provides the opportunity to design translational research on patient material stored in national biobanks. However, there are currently no standardized guidelines for the types of material, processing, and storage for leukaemia biobanking. To address this gap, we conducted a modified Delphi survey among 53 experts in different roles related to leukaemia. The first round consisted of 63 statements asking for level of agreement. The second round refined some to reach consensus, using yes-no and multiple-option answers. Key recommendations include cryopreservation of cells from diagnosis, post-induction, post-consolidation, and relapse, with at least two aliquots of plasma and serum, and cerebrospinal fluid from diagnosis, day15, and post-induction. It was advised to distribute cells across multiple vials for various research projects, and to collect data on sample processing, cell viability, and blast percentage. Quality monitoring and user feedback were strongly recommended. The Delphi survey resulted in strong recommendations that can be used by national biobanks to harmonize storage of samples from patients with ALL and ensure high-quality cryopreserved cells for research studies.
PMID:39987377 | DOI:10.1038/s41416-025-02958-x
Fokker-Planck diffusion maps of microglial transcriptomes reveal radial differentiation into substates associated with Alzheimer's pathology
Commun Biol. 2025 Feb 22;8(1):279. doi: 10.1038/s42003-025-07594-y.
ABSTRACT
The identification of microglia subtypes is important for understanding the role of innate immunity in neurodegenerative diseases. Current methods of unsupervised cell type identification assume a small noise-to-signal ratio of transcriptome measurements to produce well-separated cell clusters. However, identification of subtypes can be obscured by gene expression noise, which diminishes the distances in transcriptome space between distinct cell types, blurs boundaries, and reduces reproducibility. Here we use Fokker-Planck (FP) diffusion maps to model cellular differentiation as a stochastic process whereby cells settle into local minima that correspond to cell subtypes, in a potential landscape constructed from transcriptome data using a nearest neighbor graph approach. By applying critical transition fields, we identify individual cells on the verge of transitioning between subtypes, revealing microglial cells in an inactivated, homeostatic state before radially transitioning into various specialized subtypes. Specifically, we show that cells from Alzheimer's disease patients are enriched in a microglia subtype associated to antigen presentation and T-cell recruitment, and are depleted in an anti-inflammatory subtype.
PMID:39987247 | DOI:10.1038/s42003-025-07594-y
Multiomic QTL mapping reveals phenotypic complexity of GWAS loci and prioritizes putative causal variants
Cell Genom. 2025 Feb 16:100775. doi: 10.1016/j.xgen.2025.100775. Online ahead of print.
ABSTRACT
Most GWAS loci are presumed to affect gene regulation; however, only ∼43% colocalize with expression quantitative trait loci (eQTLs). To address this colocalization gap, we map eQTLs, chromatin accessibility QTLs (caQTLs), and histone acetylation QTLs (haQTLs) using molecular samples from three early developmental-like tissues. Through colocalization, we annotate 10.4% (n = 540) of GWAS loci in 15 traits by QTL phenotype, temporal specificity, and complexity. We show that integration of chromatin QTLs results in a 2.3-fold higher annotation rate of GWAS loci because they capture distal GWAS loci missed by eQTLs, and that 5.4% (n = 13) of GWAS colocalizing eQTLs are early developmental specific. Finally, we utilize the iPSCORE multiomic QTLs to prioritize putative causal variants overlapping transcription factor motifs to elucidate the potential genetic underpinnings of 296 GWAS-QTL colocalizations.
PMID:39986281 | DOI:10.1016/j.xgen.2025.100775
Divergence in the effects of sugar feedback regulation on the major gene regulatory network and metabolism of photosynthesis in leaves between the two founding Saccharum species
Plant J. 2025 Feb;121(4):e70019. doi: 10.1111/tpj.70019.
ABSTRACT
Sugarcane is a crop that accumulates sucrose with high photosynthesis efficiency. Therefore, the feedback regulation of sucrose on photosynthesis is crucial for improving sugarcane yield. Saccharum spontaneum and Saccharum officinarum are the two founding Saccharum species for modern sugarcane hybrids. S. spontaneum exhibits a higher net photosynthetic rate but lower sucrose content than S. officinarum. However, the mechanism underlying the negative feedback regulation of photosynthesis by sucrose remains poorly understood. This study investigates the effects of exogenous sucrose treatment on S. spontaneum and S. officinarum. Exogenous sucrose treatment increases sucrose content in the leaf base but inhibits photosynthetic efficiency and the expression of photosynthesis-related pathway genes (including RBCS and PEPC) in both species. However, gene expression patterns differed significantly, with few differentially expressed genes (DEGs) shared between the two species, indicating a differential response to exogenous sucrose. The expression networks of key genes involved in sugar metabolism, sugar transport, and PEPC and RBCS showed divergence between two species. Additionally, DEGs involved in the pentose phosphate pathway and the metabolism of alanine, aspartate, and glutamate metabolism were uniquely enriched in S. spontaneum, potentially contributing to the differential changes in sucrose content in the tip between the two species. We propose a model of the mechanisms underlying the negative feedback regulation of photosynthesis by sucrose in the leaves of S. spontaneum and S. officinarum. Our findings enhance the understanding of sucrose feedback regulation on photosynthesis and provide insights into the divergent molecular mechanisms of sugar accumulation in Saccharum.
PMID:39985806 | DOI:10.1111/tpj.70019
Enhancing Functional Protein Design Using Heuristic Optimization and Deep Learning for Anti-Inflammatory and Gene Therapy Applications
Proteins. 2025 Feb 22. doi: 10.1002/prot.26810. Online ahead of print.
ABSTRACT
Protein sequence design is a highly challenging task, aimed at discovering new proteins that are more functional and producible under laboratory conditions than their natural counterparts. Deep learning-based approaches developed to address this problem have achieved significant success. However, these approaches often do not adequately emphasize the functional properties of proteins. In this study, we developed a heuristic optimization method to enhance key functionalities such as solubility, flexibility, and stability, while preserving the structural integrity of proteins. This method aims to reduce laboratory demands by enabling a design that is both functional and structurally sound. This approach is particularly valuable for the synthetic production of proteins with anti-inflammatory properties and those used in gene therapy. The designed proteins were initially evaluated for their ability to preserve natural structures using recovery and confidence metrics, followed by assessments with the AlphaFold tool. Additionally, natural protein sequences were mutated using a genetic algorithm and compared with those designed by our method. The results demonstrate that the protein sequences generated by our method exhibit much greater similarity to native protein sequences and structures. The code and sequences for the designed proteins are available at https://github.com/aysenursoyturk/HMHO.
PMID:39985803 | DOI:10.1002/prot.26810
Protocol for the purification and crystallization of the Drosophila melanogaster Cfp1<sup>PHD</sup> domain in complex with an H3K4me3 peptide
STAR Protoc. 2025 Feb 21;6(1):103649. doi: 10.1016/j.xpro.2025.103649. Online ahead of print.
ABSTRACT
The tri-methylation of histone H3 on K4 (H3K4me3) is a key epigenetic modification that is predominantly found at active gene promoters and is deposited by the complex of proteins associated with SET1 (COMPASS). CXXC zinc finger protein 1 (Cfp1) regulates this process by recruiting SET1 to chromatin and recognizing H3K4me3 via its plant homeodomain (Cfp1PHD). Here, we present a protocol for the purification and crystallization of the Drosophila melanogaster Cfp1PHD domain in complex with an H3K4me3 peptide (PDB: 9C0O). We describe steps for obtaining highly pure Cfp1PHD and diffraction-quality crystals. We then detail procedures for rapidly identifying crystals containing the H3K4me3-bound form of the Cfp1PHD domain. For complete details on the use and execution of this protocol, please refer to Grégoire et al.1.
PMID:39985772 | DOI:10.1016/j.xpro.2025.103649
Impaired mitochondrial integrity and compromised energy production underscore the mechanism underlying CoASY protein-associated neurodegeneration
Cell Mol Life Sci. 2025 Feb 22;82(1):84. doi: 10.1007/s00018-025-05576-1.
ABSTRACT
Coenzyme A (CoA) is a crucial metabolite involved in various biological processes, encompassing lipid metabolism, regulation of mitochondrial function, and membrane modeling. CoA deficiency is associated with severe human diseases, such as Pantothenate Kinase-Associated Neurodegeneration (PKAN) and CoASY protein-associated neurodegeneration (CoPAN), which are linked to genetic mutations in Pantothenate Kinase 2 (PANK2) and CoA Synthase (CoASY). Although the association between CoA deficiency and mitochondrial dysfunction has been established, the underlying molecular alterations and mechanisms remain largely elusive. In this study, we investigated the detailed changes resulting from the functional decline of CoASY using the Drosophila model. Our findings revealed that a reduction of CoASY in muscle and brain led to degenerative phenotypes and apoptosis, accompanied by impaired mitochondrial integrity. The release of mitochondrial DNA was notably augmented, while the assembly and activity of mitochondrial electron transport chain (ETC) complexes, particularly complex I and III, were diminished. Consequently, this resulted in decreased ATP generation, rendering the fly more susceptible to energy insufficiency. Our findings suggest that compromised mitochondrial integrity and energy supply play a crucial role in the pathogenesis associated with CoA deficiency, thereby implying that enhancing mitochondrial integrity can be considered a potential therapeutic strategy in future interventions.
PMID:39985665 | DOI:10.1007/s00018-025-05576-1
Engineered <em>Vibrio natriegens</em> with a Toxin-Antitoxin System for High-Productivity Biotransformation of l-Lysine to Cadaverine
J Agric Food Chem. 2025 Feb 22. doi: 10.1021/acs.jafc.4c12616. Online ahead of print.
ABSTRACT
Vibrio natriegens, a fast-growing bacterium, is an emerging chassis of next-generation industrial biotechnology capable of thriving under open and continuous culture conditions. Cadaverine, a valuable industrial C5 platform chemical, has various chemical and biological activities. This study found that V. natriegens exhibited superior tolerance to lysine, the substrate of cadaverine production. For the first time, a cadaverine synthesis pathway was introduced into V. natriegens for whole-cell catalysis of cadaverine from lysine. A high-efficiency cadaverine-producing strain harboring a toxin-antitoxin system, V. natriegens (pSEVA341-pTac-ldcC-pHbpBC-hbpBC) with lysE (PN96_RS17440) inactivation, was constructed. In 7 L bioreactors, the cadaverine titer increased from 115 g/L in the original strain to 158 g/L within 11 h of biotransformation, exhibiting a 37% increase in production. Its productivity reached 14.4 g/L/h with a conversion rate as high as 90%. These results confirm V. natriegens as an exceptional chassis for effective cadaverine bioproduction.
PMID:39985470 | DOI:10.1021/acs.jafc.4c12616
Concerning Modern System Biology Materials Discussed at the Scientific Conference «Assessment of Quality of Life in Cancer Patients Covered in Experimental and Clinical Oncology Publications: Challenges and Opportunities», October 3-4, 2024, Kyiv, Ukraine
Exp Oncol. 2025 Feb 20;46(4):408-409. doi: 10.15407/exp-oncology.2024.04.408.
ABSTRACT
The Conference was organized on the initiative of the R.E. Kavetsky Institute of Experimental Pathology, Oncology and Radiobiology of the National Academy of Sciences of Ukraine, the State Institution "SP Grigoriev Institute of Medical Radiology and Oncology of the National Academy of Medical Sciences of Ukraine", and public organizations "National Association of Oncologists of Ukraine" and "Ukrainian Society for Cancer Research". The cancer patient's health and the quality of life (QoL) was put in the focus of this conference. Various edges of cancer research were discussed by researchers together with medical doctors, clinical scientists, specialists in demography, economics, law, and the general public.
PMID:39985343 | DOI:10.15407/exp-oncology.2024.04.408
Oral delivery of therapeutic proteins by engineered bacterial type zero secretion system
Nat Commun. 2025 Feb 21;16(1):1862. doi: 10.1038/s41467-025-57153-6.
ABSTRACT
Genetically engineered commensal bacteria are promising living drugs, however, their therapeutic molecules are frequently confined to their colonization sites. Herein, we report an oral protein delivery technology utilizing an engineered bacterial type zero secretion system (T0SS) via outer membrane vesicles (OMVs). We find that OMVs produced in situ by Escherichia coli Nissle 1917 (EcN) can penetrate the intact gut epithelial barrier to enter the circulation and that epithelial transcytosis involves pinocytosis and dynamin-dependent pathways. EcN is engineered to endogenously load various enzymes into OMVs, and the secreted enzyme-loaded OMVs are able to stably catalyze diverse detoxification reactions against digestive fluid and even enter the circulation. Using hyperuricemic mice and uricase delivery as a demonstration, we demonstrate that the therapeutic efficacy of our engineered EcN with a modified T0SS outperforms that with a direct protein secretion apparatus. The enzyme-loaded OMVs also effectively detoxify human serum samples, highlighting the potential for the clinical treatment of metabolic disorders.
PMID:39984501 | DOI:10.1038/s41467-025-57153-6
The physical roles of different posterior tissues in zebrafish axis elongation
Nat Commun. 2025 Feb 21;16(1):1839. doi: 10.1038/s41467-025-56334-7.
ABSTRACT
Shaping embryonic tissues requires spatiotemporal changes in genetic and signaling activity as well as in tissue mechanics. Studies linking specific molecular perturbations to changes in the tissue physical state remain sparse. Here we study how specific genetic perturbations affecting different posterior tissues during zebrafish body axis elongation change their physical state, the resulting large-scale tissue flows, and posterior elongation. Using a custom analysis software to reveal spatiotemporal variations in tissue fluidity, we show that dorsal tissues are most fluid at the posterior end, rigidify anterior of this region, and become more fluid again yet further anteriorly. In the absence of notochord (noto mutants) or when the presomitic mesoderm is substantially reduced (tbx16 mutants), dorsal tissues elongate normally. Perturbations of posterior-directed morphogenetic flows in dorsal tissues (vangl2 mutants) strongly affect the speed of elongation, highlighting the essential role of dorsal cell flows in delivering the necessary material to elongate the axis.
PMID:39984461 | DOI:10.1038/s41467-025-56334-7
Exploring the principles behind antibiotics with limited resistance
Nat Commun. 2025 Feb 21;16(1):1842. doi: 10.1038/s41467-025-56934-3.
ABSTRACT
Antibiotics that target multiple cellular functions are anticipated to be less prone to bacterial resistance. Here we hypothesize that while dual targeting is crucial, it is not sufficient in preventing resistance. Only those antibiotics that simultaneously target membrane integrity and block another cellular pathway display reduced resistance development. To test the hypothesis, we focus on three antibiotic candidates, POL7306, Tridecaptin M152-P3 and SCH79797, all of which fulfill the above criteria. Here we show that resistance evolution against these antibiotics is limited in ESKAPE pathogens, including Escherichia coli, Klebsiella pneumoniae, Acinetobacter baumannii and Pseudomonas aeruginosa, while dual-target topoisomerase antibiotics are prone to resistance. We discover several mechanisms restricting resistance. First, de novo mutations result in only a limited elevation in resistance, including those affecting the molecular targets and efflux pumps. Second, resistance is inaccessible through gene amplification. Third, functional metagenomics reveal that mobile resistance genes are rare in human gut, soil and clinical microbiomes. Finally, we detect rapid eradication of bacterial populations upon toxic exposure to membrane targeting antibiotics. We conclude that resistance mechanisms commonly found in natural bacterial pathogens provide only limited protection to these antibiotics. Our work provides guidelines for the future development of antibiotics.
PMID:39984459 | DOI:10.1038/s41467-025-56934-3
Modified Decision Tree with Custom Splitting Logic Improves Generalization across Multiple Brains' Proteomic Data Sets of Alzheimer's Disease
J Proteome Res. 2025 Feb 21. doi: 10.1021/acs.jproteome.4c00677. Online ahead of print.
ABSTRACT
Many factors negatively affect a generalization of the findings in discovery proteomics. They include differentiation between patient cohorts, a variety of experimental conditions, etc. We presented a machine-learning-based workflow for proteomics data analysis, aiming at improving generalizability across multiple data sets. In particular, we customized the decision tree model by introducing a new parameter, min_groups_leaf, which regulates the presence of the samples from each data set inside the model's leaves. Further, we analyzed a trend for the feature importance's curve as a function of the novel parameter for feature selection to a list of proteins with significantly improved generalization. The developed workflow was tested using five proteomic data sets obtained for post-mortem human brain samples of Alzheimer's disease. The data sets consisted of 535 LC-MS/MS acquisition files. The results were obtained for two different pipelines of data processing: (1) MS1-only processing based on DirectMS1 search engine and (2) a standard MS/MS-based one. Using the developed workflow, we found seven proteins with expression patterns that were unique for asymptomatic Alzheimer patients. Two of them, Serotransferrin TRFE and DNA repair nuclease APEX1, may be potentially important for explaining the lack of dementia in patients with the presence of neuritic plaques and neurofibrillary tangles.
PMID:39984290 | DOI:10.1021/acs.jproteome.4c00677
Computational insights into fucoidan-receptor binding: implications for fucoidan-based targeted drug delivery
Drug Discov Today. 2025 Feb 19:104315. doi: 10.1016/j.drudis.2025.104315. Online ahead of print.
ABSTRACT
Fucoidan, a polysaccharide from seaweed, holds promise as a drug delivery system and immune modulator; however, its exact mechanism of action remains unclear. As various carbohydrates play key roles in immune responses by binding to carbohydrate-binding proteins like lectins, fucoidan is hypothesized to interact with immune receptors, potentially driving its anticancer activities. However, structural variability, extraction-induced heterogeneity, and weak binding affinities pose challenges to research. Computational tools offer valuable insights into fucoidan-receptor interactions, addressing these challenges and enabling the design of more effective therapies. This review examines fucoidan's therapeutic activities, drug delivery potential, and receptor interactions, emphasizing computational approaches to advance immune modulation and anticancer applications using carbohydrate polymers.
PMID:39984116 | DOI:10.1016/j.drudis.2025.104315
Deciphering the digenic architecture of congenital heart disease using trio exome sequencing data
Am J Hum Genet. 2025 Feb 18:S0002-9297(25)00044-8. doi: 10.1016/j.ajhg.2025.01.024. Online ahead of print.
ABSTRACT
Congenital heart disease (CHD) is the most common congenital anomaly and a leading cause of infant morbidity and mortality. Despite extensive exploration of the monogenic causes of CHD over the last decades, ∼55% of cases still lack a molecular diagnosis. Investigating digenic interactions, the simplest form of oligogenic interactions, using high-throughput sequencing data can elucidate additional genetic factors contributing to the disease. Here, we conducted a comprehensive analysis of digenic interactions in CHD by utilizing a large CHD trio exome sequencing cohort, comprising 3,910 CHD and 3,644 control trios. We extracted pairs of presumably deleterious rare variants observed in CHD-affected and unaffected children but not in a single parent. Burden testing of gene pairs derived from these variant pairs revealed 29 nominally significant gene pairs. These gene pairs showed a significant enrichment for known CHD genes (p < 1.0 × 10-4) and exhibited a shorter average biological distance to known CHD genes than expected by chance (p = 3.0 × 10-4). Utilizing three complementary biological relatedness approaches including network analyses, biological distance calculations, and candidate gene prioritization methods, we prioritized 10 final gene pairs that are likely to underlie CHD. Analysis of bulk RNA-sequencing data showed that these genes are highly expressed in the developing embryonic heart (p < 1 × 10-4). In conclusion, our findings suggest the potential role of digenic interactions in CHD pathogenesis and provide insights into unresolved molecular diagnoses. We suggest that the application of the digenic approach to additional disease cohorts will significantly enhance genetic discovery rates.
PMID:39983722 | DOI:10.1016/j.ajhg.2025.01.024
TGF-β signaling controls neural crest developmental plasticity via SMAD2/3
Dev Cell. 2025 Feb 18:S1534-5807(25)00059-0. doi: 10.1016/j.devcel.2025.01.018. Online ahead of print.
ABSTRACT
The neural crest is a highly plastic stem cell population that represents an exception to the germ layer theory. Despite being of ectodermal origin, cranial neural crest cells can differentiate into skeletal derivatives typically formed by mesoderm. Here, we report that SMAD2/3-mediated transforming growth factor β (TGF-β) signaling enhances neural crest developmental potential in the chicken embryo. Our results show that TGF-β signaling modulates neural crest axial identity and directly controls the gene circuits that support skeletal differentiation. Cooperation between TGF-β and low levels of WNT signaling in the embryonic head activates cranial-specific cis-regulatory elements. Activation of TGF-β signaling reprogrammed trunk neural crest cells into adopting an anterior identity and led to the development of an improved protocol for the generation of human cranial neural crest cells. Our findings indicate TGF-β signaling is required for the specification of cranial neural crest cells, endowing them with the potential to give rise to the craniofacial skeleton.
PMID:39983721 | DOI:10.1016/j.devcel.2025.01.018
Plasmodesmata act as unconventional membrane contact sites regulating intercellular molecular exchange in plants
Cell. 2025 Feb 20;188(4):958-977.e23. doi: 10.1016/j.cell.2024.11.034.
ABSTRACT
Membrane contact sites (MCSs) are fundamental for intracellular communication, but their role in intercellular communication remains unexplored. We show that in plants, plasmodesmata communication bridges function as atypical endoplasmic reticulum (ER)-plasma membrane (PM) tubular MCSs, operating at cell-cell interfaces. Similar to other MCSs, ER-PM apposition is controlled by a protein-lipid tethering complex, but uniquely, this serves intercellular communication. Combining high-resolution microscopy, molecular dynamics, and pharmacological and genetic approaches, we show that cell-cell trafficking is modulated through the combined action of multiple C2 domains transmembrane domain proteins (MCTPs) 3, 4, and 6 ER-PM tethers and phosphatidylinositol-4-phosphate (PI4P) lipid. Graded PI4P amounts regulate MCTP docking to the PM, their plasmodesmata localization, and cell-cell permeability. SAC7, an ER-localized PI4P-phosphatase, regulates MCTP4 accumulation at plasmodesmata and modulates cell-cell trafficking capacity in a cell-type-specific manner. Our findings expand MCS functions in information transmission from intracellular to intercellular cellular activities.
PMID:39983675 | DOI:10.1016/j.cell.2024.11.034
Reduction of the geomagnetic field to hypomagnetic field modulates tomato (Solanum lycopersicum L. cv Microtom) gene expression and metabolomics during plant development
J Plant Physiol. 2025 Feb 15;306:154453. doi: 10.1016/j.jplph.2025.154453. Online ahead of print.
ABSTRACT
An interesting aspect that links the geomagnetic field (GMF) to the evolution of life lies in how plants respond to the reduction of the GMF, also known as hypomagnetic field (HMF). In this work, tomato plants (Solanum lycopersicum cv Microtom) were exposed either to GMF or HMF and were studied during the development of leaves and fruit set. Changes of expression of genes encoding for primary and secondary metabolites, including Reactive Oxygen Species (ROS), proteins, fatty acids, polyphenols, chlorophylls, carotenoids and phytohormones were assessed by qRT-PCR, while the corresponding metabolite levels were quantified by GC-MS and HPLC-MS. Two tomato homologs of the fruit fly magnetoreceptor MagR, Isca-like 1 and erpA 2, were modulated by HMF, as were numerous tomato genes under investigation. In tomato leaves, positive correlations were observed with most of the genes associated with phytohormones production, ROS scavenging and production, and lipid metabolism, whereas an almost reversed trend was found in flowers and fruits. Interestingly, downregulation of Isca-like 1 and erpA 2 was found to correlate with an upregulation of most unripe fruit genes. Exposure to HMF reduced chlorophyll and carotenoid content, decreased photosynthetic efficiency and increased non-photochemical quenching. Auxins, gibberellins, cytokinins, abscisic acid, jasmonic acid and salicylic acid content and the expression of genes related to their metabolism correlated with tomato ISCA modulation. The results here reported suggest that Isca-like 1 and erpA 2 might be important players in tomato magnetoreception.
PMID:39983659 | DOI:10.1016/j.jplph.2025.154453
Isolation and characterization of 24 phages infecting the plant growth-promoting rhizobacterium Klebsiella sp. M5al
PLoS One. 2025 Feb 21;20(2):e0313947. doi: 10.1371/journal.pone.0313947. eCollection 2025.
ABSTRACT
Bacteriophages largely impact bacterial communities via lysis, gene transfer, and metabolic reprogramming and thus are increasingly thought to alter nutrient and energy cycling across many of Earth's ecosystems. However, there are few model systems to mechanistically and quantitatively study phage-bacteria interactions, especially in soil systems. Here, we isolated, sequenced, and genomically characterized 24 novel phages infecting Klebsiella sp. M5al, a plant growth-promoting, nonencapsulated rhizosphere-associated bacterium, and compared many of their features against all 565 sequenced, dsDNA Klebsiella phage genomes. Taxonomic analyses revealed that these Klebsiella phages belong to three known phage families (Autographiviridae, Drexlerviridae, and Straboviridae) and two newly proposed phage families (Candidatus Mavericviridae and Ca. Rivulusviridae). At the phage family level, we found that core genes were often phage-centric proteins, such as structural proteins for the phage head and tail and DNA packaging proteins. In contrast, genes involved in transcription, translation, or hypothetical proteins were commonly not shared or flexible genes. Ecologically, we assessed the phages' ubiquity in recent large-scale metagenomic datasets, which revealed they were not widespread, as well as a possible direct role in reprogramming specific metabolisms during infection by screening their genomes for phage-encoded auxiliary metabolic genes (AMGs). Even though AMGs are common in the environmental literature, only one of our phage families, Straboviridae, contained AMGs, and the types of AMGs were correlated at the genus level. Host range phenotyping revealed the phages had a wide range of infectivity, infecting between 1-14 of our 22 bacterial strain panel that included pathogenic Klebsiella and Raoultella strains. This indicates that not all capsule-independent Klebsiella phages have broad host ranges. Together, these isolates, with corresponding genome, AMG, and host range analyses, help build the Klebsiella model system for studying phage-host interactions of rhizosphere-associated bacteria.
PMID:39982899 | DOI:10.1371/journal.pone.0313947
ChIP provides 10-fold microbial DNA enrichment from tissue while minimizing bias
Mol Biol Rep. 2025 Feb 21;52(1):258. doi: 10.1007/s11033-025-10330-8.
ABSTRACT
BACKGROUND: Host DNA depletion is a critical tool for accessing the microbiomes of samples that have a small amount of microbial DNA contained in a high host background. Of critical practical importance is the ability to identify microbial DNA sequences in frozen tissue specimens. Here, we compare four existing commercial methods and two newly introduced methods involving chromatin immunoprecipitation (ChIP) on frozen human and pig intestinal biopsies.
RESULTS: We find that all methods that rely on differential lysis of host and microbial cells introduce substantial biases as assessed by 16 S rRNA gene amplicon profiling. However, ChIP enables 10-fold enrichment of microbial DNA while introducing less bias, sufficient to make assessment possible against background, in both pigs and humans.
CONCLUSIONS: We recommend ChIP in situations where host depletion is important but where minimizing taxonomic bias is essential, and the MolYsis or Zymo kit for situations where host depletion level is more important than taxonomic bias.
CONCLUSIONS: We recommend ChIP in situations where host depletion is important but where minimizing taxonomic bias is essential, and the MolYsis or Zymo kit for situations where host depletion level is more important than taxonomic bias.
PMID:39982577 | DOI:10.1007/s11033-025-10330-8