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.
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).
Project description:Human scalp hair follicles were snapfrozen directly after surgery or organ-cultured in the presence/absence of SEP1 phages. After treatment total RNA was isolated and prepared for RNA-seq
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.