Background: Jumbo phages, phages with genomes > 200 kbp, contain some unique genes for successful reproduction in their bacterial hosts. Due to complex and massive genomes analogous to those of small-celled bacteria, how jumbo phages complete their life cycle remains largely undefined.
Results: In this study, we assembled 668 high-quality jumbo phage genomes from over 15 terabytes (TB) of intestinal metagenomic data from 955 samples of 5 animal species (cow, sheep, pig, horse, and deer). Within them, we obtained a complete genome of 716 kbp in length, which is the largest phage genome so far reported in the gut environments. Interestingly, 174 out of the 668 jumbo phages were found to encode all genes required for the synthesis of NAD by the salvage pathway or Preiss-Handler pathway, referred to as NAD-jumbo phage. Besides synthesis genes of NAD, these NAD-jumbo phages also encode at least 15 types of NAD-consuming enzyme genes involved in DNA replication, DNA repair, and counterdefense, suggesting that these phages not only have the capacity to synthesize NAD but also redirect NAD metabolism towards phage propagation need in hosts. Phylogenetic analysis and environmental survey indicated NAD-jumbo phages are widely present in the Earth's ecosystems, including the human gut, lakes, salt ponds, mine tailings, and seawater.
Conclusion: In summary, this study expands our understanding of the diversity and survival strategies of phages, and an in-depth study of the NAD-jumbo phages is crucial for understanding their role in ecological regulation. Video Abstract.
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http://dx.doi.org/10.1186/s40168-024-01984-w | DOI Listing |
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC11662467 | PMC |
Microbiome
December 2024
College of Life Sciences, Shihezi University, Shihezi, Xinjiang, 832003, China.
Nucleic Acids Res
December 2024
Department of Microbiology and Immunology, University of Otago, PO Box 56, Dunedin 9054, New Zealand.
The Chimalliviridae family of bacteriophages (phages) form a proteinaceous nucleus-like structure during infection of their bacterial hosts. This phage 'nucleus' compartmentalises phage DNA replication and transcription, and shields the phage genome from DNA-targeting defence systems such as CRISPR-Cas and restriction-modification. Their insensitivity to DNA-targeting defences makes nucleus-forming jumbo phages attractive for phage therapy.
View Article and Find Full Text PDFAntibiotics (Basel)
October 2024
Extension Division, National Veterinary Research Institute NVRI, Vom 930001, Nigeria.
is a bacteria responsible for many hospital-acquired infections. Phages are promising alternatives for treating infections, which are often intrinsically resistant. The combination of phage and antibiotics in clearing bacterial infection holds promise due to increasing reports of enhanced effectiveness when both are used together.
View Article and Find Full Text PDFArch Virol
November 2024
Graduate School of Agricultural Science, Tohoku University, Sendai, Miyagi, 980-0845, Japan.
Microbiol Resour Announc
November 2024
Wound Infections Department, Bacterial Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, Maryland, USA.
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