Bacteroides phage SHe-2020a
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ABSTRACT:
PROVIDER: PRJNA638235 | ENA |
REPOSITORIES: ENA
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Project description:isolation of 42 skin isolated phages
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Project description:Retrons are bacterial genetic elements that encode a reverse transcriptase and, in combination with toxic effector proteins, can serve as antiphage defense systems. However, the mechanisms of action of most retron effectors, and how phages evade retrons, are not well understood. Here, we show that some phages can evade retrons and other defense systems by producing specific tRNAs. We find that expression of retron-Eco7 effector proteins (PtuA and PtuB) leads to degradation of tRNA-Tyr and abortive infection. The genomes of T5 phages that evade retron-Eco7 include a tRNA-rich region, including a highly expressed tRNA-Tyr gene, which confers protection against retron-Eco7. Furthermore, we show that other phages (T1, T7) can use a similar strategy, expressing a tRNA-Lys, to counteract a tRNA anticodon defense system (PrrC170).
2024-09-12 | GSE229290 | GEO
Project description:Virulent bacteriophages (or phages) are viruses that specifically infect and lyse a bacterial host. When multiple phages co-infect a bacterial host, the extent of lysis, dynamics of bacteria-phage and phage-phage interactions are expected to vary. The objective of this study is to identify the factors influencing the interaction of two virulent phages with different Pseudomonas aeruginosa growth states (planktonic, an infected epithelial cell line, and biofilm) by measuring the bacterial time-kill and individual phage replication kinetics. A single administration of phages effectively reduced P. aeruginosa viability in planktonic conditions and infected human lung cell cultures, but phage-resistant variants subsequently emerged. In static biofilms, the phage combination displayed initial inhibition of biofilm dispersal, but sustained control was achieved only by combining phages and meropenem antibiotic. In contrast, adherent biofilms showed tolerance to phage and/or meropenem, suggesting a spatiotemporal variation in the phage-bacterial interaction. The kinetics of adsorption of each phage to P. aeruginosa during single- or co-administration were comparable. However, the phage with the shorter lysis time depleted bacterial resources early and selected a specific nucleotide polymorphism that conferred a competitive disadvantage and cross-resistance to the second phage. The extent and strength of this phage-phage competition and genetic loci conferring phage resistance, are, however, P. aeruginosa genotype dependent. Nevertheless, adding phages sequentially resulted in their unimpeded replication with no significant increase in bacterial host lysis. These results highlight the interrelatedness of phage-phage competition, phage resistance and specific bacterial growth state (planktonic/biofilm) in shaping the interplay among P. aeruginosa and virulent phages.
2024-07-17 | GSE271537 | GEO
Project description:Success of phage therapies is limited by bacterial defenses against phages. While a variety of anti-phage defense mechanisms has been characterized, how expression of these systems is distributed across individual cells and how their combined activities translate into protection from phages has not been studied. Using bacterial single-cell RNA sequencing, we profiled the transcriptomes of ~50,000 cells from cultures of a human pathobiont, Bacteroides fragilis, infected with a lytic bacteriophage. We quantified the asynchronous progression of phage infection in single bacterial cells and reconstructed the infection timeline, characterizing both host and phage transcriptomic changes as infection unfolded. We discovered subpopulations of bacteria that remained uninfected and heterogeneously expressed protective factors. Each cell’s vulnerability to phage infection was defined by combinatorial expression of multiple genetic loci, including phase-variable capsular polysaccharide (CPS) biosynthesis pathways, restriction-modification systems (RM), and a novel operon predicted to encode fimbrial genes. Acting in concert, these heterogeneously expressed anti-phage defense mechanisms create a phenotypic landscape where distinct protective combinations enable the survival and re-growth of bacteria expressing these phenotypes without acquiring additional mutations. The emerging model of complementary action of multiple protective mechanisms heterogeneously expressed across an isogenic bacterial population showcases the potent role of phase variation and stochasticity in bacterial anti-phage defenses.
2026-02-09 | GSE318809 | GEO
Project description:Phages are viruses that infect prokaryotes and can shape microbial communitiesby lysis, thus offering applications in various fields. However, challengesexist in sampling, isolation and accurate prediction of the host specificity ofphages as well as in the identification of newly replicated virions in response toenvironmental challenges. A new workflow using biorthogonal non-canonicalamino acid tagging (BONCAT) and click chemistry (CC) allowed combinedanalysis of phages and their hosts, the identification of newly replicated virions,and the specific tagging of phages with biotin for affinity chromatography.Replication of phage λ in Escherichia coli was selected as a model for workflowdevelopment. Specific labeling of phage λ proteins with the non-canonicalamino acid 4-azido-L-homoalanine (AHA) during phage development in E. coliwas confirmed by LC–MS/MS. Subsequent tagging of AHA with fluorescentdyes via CC allowed the visualization of phages adsorbed to the cell surfaceby fluorescence microscopy. Flow cytometry enabled the automated detectionof these fluorescent phage-host complexes. Alternatively, AHA-labeled phageswere tagged with biotin for purification by affinity chromatography. Despitebiotinylation the tagged phages could be purified and were infectious afterpurification. Applying this approach to environmental samples would enablehost screening without cultivation. A flexible and powerful workflow for thedetection and enrichment of phages and their hosts in pure cultures has beenestablished. The developed method lays the groundwork for future workflowsthat could enable the isolation of phage-host complexes from diverse complexmicrobial communities using fluorescence-activated cell sorting or biotinpurification. The ability to expand and customize the workflow through thegrowing range of compounds for CC offers the potential to develop a versatiletoolbox in phage research. This work provides a starting point for these furtherstudies by providing a comprehensive standard operating procedure.
2024-08-29 | PXD044316 | Pride
Project description:The interactions between lytic phages and their hosts are typically studied in bulk culture, which obscures cell-cell differences in infection susceptibility or expression of protective factors. Here, we use bacterial single-cell RNA sequencing to profile the transcriptomes of ~50,000 cells from cultures of a human pathobiont, Bacteroides fragilis, infected with a lytic bacteriophage. From a single sampling, we quantified the asynchronous progression of phage infection in individual bacterial cells and reconstructed the infection timeline, characterizing both host and phage transcriptomic changes as infection unfolded. Further, we discovered phenotypic subpopulations of bacteria that remained uninfected. Each cell's vulnerability to phage infection was influenced by expression of multiple genetic loci, most prominently phase-variable capsular polysaccharide (CPS) biosynthesis pathways and an operon predicted to encode fimbrial genes. These findings uncovered genome-wide phase variation and stochasticity that enable bacterial survival and re-growth without acquiring additional mutations. Overall, we establish bacterial single-cell RNA sequencing as a powerful platform for investigating the dynamics of host-phage interactions and revealing the roles of phase variation and stochasticity in bacterial defenses.
2026-01-15 | GSE309504 | GEO
Project description:The efficacy of bacteriophages in treating bacterial infections largely depends on the phages’ vitality, which is impaired when they are naturally released from their hosts, as well as by culture media, manufacturing processes and other insults. Here, by wrapping phage-invaded bacteria individually with a polymeric nanoscale coating to preserve the microenvironment on phage-induced bacterial lysis, we show that, compared with naturally released phages, which have severely degraded proteins in their tail, the vitality of phages isolated from polymer-coated bacteria is maintained. Such latent phages could also be better amplified, and they more efficiently bound and lysed bacteria when clearing bacterial biofilms. In mice with bacterially induced enteritis and associated arthritis, latent phages released from orally administered bacteria coated with a polymer that dissolves at neutral pH had higher bioavailability and led to substantially better therapeutic outcomes than the administration of uncoated phages.
2025-02-05 | PXD054755 | Pride
Project description:By entering a reversible state of reduced metabolic activity, dormant microorganisms are able to contend with suboptimal conditions that would otherwise reduce their fitness. In addition, certain types of dormancy like sporulation, can serve as a refuge from parasitic infections. Phages are unable to attach to spores, but their genomes can be entrapped in the resting structures and are able to resume infection upon host germination. Thus, dormancy has the potential to affect both the reproductive and survival components of phage fitness. Here, we characterized the distribution and diversity of sigma factors in nearly 3,500 phage genomes. Homologs of bacterial sigma factors that are responsible for directing transcription during sporulation were preferentially recovered in phages that infect spore-forming hosts. While non-essential for lytic infection, when expressed in Bacillus subtilis, we demonstrate that phage-encoded sigma factors activated sporulation gene networks and reduced spore yield. Our findings suggest that the acquisition of host-like transcriptional regulators may allow phages to manipulate the expression of complex traits, like the transitions involved in bacterial dormancy.
2021-11-05 | GSE187004 | GEO
Project description:Many, if not all, bacteria use quorum sensing (QS) to control gene expression and collective behaviours, and more recently QS has also been discovered in bacteriophages (phages). Phages can produce communication molecules of their own, or “listen in” on the host’s communication processes, in order to switch between lytic and lysogenic modes of infection. In this project, we studied the interaction of Vibrio cholerae, the causative agent of cholera disease, with the lysogenic vibriophage VP882. The lytic cycle of VP882 is induced by the QS molecule DPO (3,5-dimethylpyrazin-2-ol), however, the global regulatory consequences of DPO-mediated VP882 activation have remained unclear.
2023-11-23 | GSE247770 | GEO
Project description:Pseudomonas phage LTe-2020a Genome sequencing and assembly
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